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 <title>Android ANDROID_VERSION Compatibility Definition</title>
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 <body>

 <h6>Table of Contents</h6>

 <div id="toc">

 <div id="toc_left">

 <p class="toc_h1"><a href="#1_introduction">1. Introduction</a></p>

 <p class="toc_h1"><a href="#2_device_types">2. Device Types</a></p>

 <p class="toc_h2"><a href="#2_1_device_configurations">2.1 Device Configurations</a></p>

 <p class="toc_h1"><a href="#3_software">3. Software</a></p>

 <p class="toc_h2"><a href="#3_1_managed_api_compatibility">3.1. Managed API Compatibility</a></p>

 <p class="toc_h2"><a href="#3_2_soft_api_compatibility">3.2. Soft API Compatibility</a></p>

 <p class="toc_h3"><a href="#3_2_1_permissions">3.2.1. Permissions</a></p>

 <p class="toc_h3"><a href="#3_2_2_build_parameters">3.2.2. Build Parameters</a></p>

 <p class="toc_h3"><a href="#3_2_3_intent_compatibility">3.2.3. Intent Compatibility</a></p>

 <p class="toc_h4"><a href="#3_2_3_1_core_application_intents">3.2.3.1. Core Application Intents</a></p>

 <p class="toc_h4"><a href="#3_2_3_2_intent_overrides">3.2.3.2. Intent Overrides</a></p>

 <p class="toc_h4"><a href="#3_2_3_3_intent_namespaces">3.2.3.3. Intent Namespaces</a></p>

 <p class="toc_h4"><a href="#3_2_3_4_broadcast_intents">3.2.3.4. Broadcast Intents</a></p>

 <p class="toc_h4"><a href="#3_2_3_5_default_app_settings">3.2.3.5. Default App Settings</a></p>

 <p class="toc_h2"><a href="#3_3_native_api_compatibility">3.3. Native API Compatibility</a></p>

 <p class="toc_h3"><a href="#3_3_1_application_binary_interfaces">3.3.1. Application Binary Interfaces</a></p>

 <p class="toc_h3"><a href="#3_3_2_32-bit_arm_native_code_compatibility">3.3.2. 32-bit ARM Native Code Compatibility</a></p>

 <p class="toc_h2"><a href="#3_4_web_compatibility">3.4. Web Compatibility</a></p>

 <p class="toc_h3"><a href="#3_4_1_webview_compatibility">3.4.1. WebView Compatibility</a></p>

 <p class="toc_h3"><a href="#3_4_2_browser_compatibility">3.4.2. Browser Compatibility</a></p>

 <p class="toc_h2"><a href="#3_5_api_behavioral_compatibility">3.5. API Behavioral Compatibility</a></p>

 <p class="toc_h2"><a href="#3_6_api_namespaces">3.6. API Namespaces</a></p>

 <p class="toc_h2"><a href="#3_7_runtime_compatibility">3.7. Runtime Compatibility</a></p>

 <p class="toc_h2"><a href="#3_8_user_interface_compatibility">3.8. User Interface Compatibility</a></p>

 <p class="toc_h3"><a href="#3_8_1_launcher_home_screen">3.8.1. Launcher (Home Screen)</a></p>

 <p class="toc_h3"><a href="#3_8_2_widgets">3.8.2. Widgets</a></p>

 <p class="toc_h3"><a href="#3_8_3_notifications">3.8.3. Notifications</a></p>

 <p class="toc_h3"><a href="#3_8_4_search">3.8.4. Search</a></p>

 <p class="toc_h3"><a href="#3_8_5_toasts">3.8.5. Toasts</a></p>

 <p class="toc_h3"><a href="#3_8_6_themes">3.8.6. Themes</a></p>

 <p class="toc_h3"><a href="#3_8_7_live_wallpapers">3.8.7. Live Wallpapers</a></p>

 <p class="toc_h3"><a href="#3_8_8_activity_switching">3.8.8. Activity Switching</a></p>

 <p class="toc_h3"><a href="#3_8_9_input_management">3.8.9. Input Management</a></p>

 <p class="toc_h3"><a href="#3_8_10_lock_screen_media_control">3.8.10. Lock Screen Media Control</a></p>

 <p class="toc_h3"><a href="#3_8_11_dreams">3.8.11. Dreams</a></p>

 <p class="toc_h3"><a href="#3_8_12_location">3.8.12. Location</a></p>

 <p class="toc_h3"><a href="#3_8_13_unicode_and_font">3.8.13. Unicode and Font</a></p>


 </div>

 <div id="toc_right"><br>


 <p class="toc_h2"><a href="#3_9_device_administration">3.9. Device Administration</a></p>

 <p class="toc_h3"><a href="#3_9_1_device_provisioning">3.9.1 Device Provisioning</a></p>

 <p class="toc_h4"><a href="#3_9_1_2_device_owner_provisioning">3.9.1.1 Device Owner provisioning</a></p>

 <p class="toc_h4"><a href="#3_9_1_2_managed_profile_provisioning">3.9.1.2 Managed profile provisioning</a></p>

 <p class="toc_h2"><a href="#3_10_accessibility">3.10. Accessibility</a></p>

 <p class="toc_h2"><a href="#3_11_text-to-speech">3.11. Text-to-Speech</a></p>

 <p class="toc_h2"><a href="#3_12_tv_input_framework">3.12. TV Input Framework</a></p>

 <p class="toc_h1"><a href="#4_application_packaging_compatibility">4. Application Packaging Compatibility</a></p>

 <p class="toc_h1"><a href="#5_multimedia_compatibility">5. Multimedia Compatibility</a></p>

 <p class="toc_h2"><a href="#5_1_media_codecs">5.1. Media Codecs</a></p>

 <p class="toc_h3"><a href="#5_1_1_audio_codecs">5.1.1. Audio Codecs</a></p>

 <p class="toc_h3"><a href="#5_1_2_image_codecs">5.1.2. Image Codecs</a></p>

 <p class="toc_h3"><a href="#5_1_3_video_codecs">5.1.3. Video Codecs</a></p>

 <p class="toc_h2"><a href="#5_2_video_encoding">5.2. Video Encoding</a></p>

 <p class="toc_h2"><a href="#5_3_video_decoding">5.3. Video Decoding</a></p>

 <p class="toc_h2"><a href="#5_4_audio_recording">5.4. Audio Recording</a></p>

 <p class="toc_h3"><a href="#5_4_1_raw_audio_capture">5.4.1. Raw Audio Capture</a></p>

 <p class="toc_h3"><a href="#5_4_2_capture_for_voice_recognition">5.4.2. Capture for Voice Recognition</a></p>

 <p class="toc_h3"><a href="#5_4_3_capture_for_rerouting_of_playback">5.4.3. Capture for Rerouting of Playback</a></p>

 <p class="toc_h2"><a href="#5_5_audio_playback">5.5. Audio Playback</a></p>

 <p class="toc_h3"><a href="#5_5_1_raw_audio_playback">5.5.1. Raw Audio Playback</a></p>

 <p class="toc_h3"><a href="#5_5_2_audio_effects">5.5.2. Audio Effects</a></p>

 <p class="toc_h3"><a href="#5_5_3_audio_output_volume">5.5.3. Audio Output Volume</a></p>

 <p class="toc_h2"><a href="#5_6_audio_latency">5.6. Audio Latency</a></p>

 <p class="toc_h2"><a href="#5_7_network_protocols">5.7. Network Protocols</a></p>

 <p class="toc_h2"><a href="#5_8_secure_media">5.8. Secure Media</a></p>

 <p class="toc_h2"><a href="#5_9_midi">5.9. Musical Instrument Digital Interface (MIDI)</a></p>

 <p class="toc_h2"><a href="#5_10_pro_audio">5.10. Professional Audio</a></p>

 <p class="toc_h1"><a href="#6_developer_tools_and_options_compatibility">6. Developer Tools and Options Compatibility</a></p>

 <p class="toc_h2"><a href="#6_1_developer_tools">6.1. Developer Tools</a></p>

 <p class="toc_h2"><a href="#6_2_developer_options">6.2. Developer Options</a></p>

 <p class="toc_h1"><a href="#7_hardware_compatibility">7. Hardware Compatibility</a></p>

 <p class="toc_h2"><a href="#7_1_display_and_graphics">7.1. Display and Graphics</a></p>

 <p class="toc_h3"><a href="#7_1_1_screen_configuration">7.1.1. Screen Configuration</a></p>

 <p class="toc_h4"><a href="#7_1_1_1_screen_size">7.1.1.1. Screen Size</a></p>

 <p class="toc_h4"><a href="#7_1_1_2_screen_aspect_ratio">7.1.1.2. Screen Aspect Ratio</a></p>

 <p class="toc_h4"><a href="#7_1_1_3_screen_density">7.1.1.3. Screen Density</a></p>


 </div>

 <div style="clear: both; page-break-after:always; height:1px"></div>


 <div id="toc_left_2">

 <p class="toc_h3"><a href="#7_1_2_display_metrics">7.1.2. Display Metrics</a></p>

 <p class="toc_h3"><a href="#7_1_3_screen_orientation">7.1.3. Screen Orientation</a></p>

 <p class="toc_h3"><a href="#7_1_4_2d_and_3d_graphics_acceleration">7.1.4. 2D and 3D Graphics Acceleration</a></p>

 <p class="toc_h3"><a href="#7_1_5_legacy_application_compatibility_mode">7.1.5. Legacy Application Compatibility Mode</a></p>

 <p class="toc_h3"><a href="#7_1_6_screen_technology">7.1.6. Screen Technology</a></p>

 <p class="toc_h3"><a href="#7_1_7_external_displays">7.1.7. Secondary Displays</a></p>

 <p class="toc_h2"><a href="#7_2_input_devices">7.2. Input Devices</a></p>

 <p class="toc_h3"><a href="#7_2_1_keyboard">7.2.1. Keyboard</a></p>

 <p class="toc_h3"><a href="#7_2_2_non-touch_navigation">7.2.2. Non-touch Navigation</a></p>

 <p class="toc_h3"><a href="#7_2_3_navigation_keys">7.2.3. Navigation Keys</a></p>

 <p class="toc_h3"><a href="#7_2_4_touchscreen_input">7.2.4. Touchscreen Input</a></p>

 <p class="toc_h3"><a href="#7_2_5_fake_touch_input">7.2.5. Fake Touch Input</a></p>

 <p class="toc_h3"><a href="#7_2_6_game_controller_support">7.2.6. Game Controller Support</a></p>

 <p class="toc_h4"><a href="#7_2_6_1_button_mapping">7.2.6.1. Button Mappings</a></p>

 <p class="toc_h3"><a href="#7_2_7_remote_control">7.2.7. Remote Control</a></p>

 <p class="toc_h2"><a href="#7_3_sensors">7.3. Sensors</a></p>

 <p class="toc_h3"><a href="#7_3_1_accelerometer">7.3.1. Accelerometer</a></p>

 <p class="toc_h3"><a href="#7_3_2_magnetometer">7.3.2. Magnetometer</a></p>

 <p class="toc_h3"><a href="#7_3_3_gps">7.3.3. GPS</a></p>

 <p class="toc_h3"><a href="#7_3_4_gyroscope">7.3.4. Gyroscope</a></p>

 <p class="toc_h3"><a href="#7_3_5_barometer">7.3.5. Barometer</a></p>

 <p class="toc_h3"><a href="#7_3_6_thermometer">7.3.6. Thermometer</a></p>

 <p class="toc_h3"><a href="#7_3_7_photometer">7.3.7. Photometer</a></p>

 <p class="toc_h3"><a href="#7_3_8_proximity_sensor">7.3.8. Proximity Sensor</a></p>

 <p class="toc_h2"><a href="#7_4_data_connectivity">7.4. Data Connectivity</a></p>

 <p class="toc_h3"><a href="#7_4_1_telephony">7.4.1. Telephony</a></p>

 <p class="toc_h3"><a href="#7_4_2_ieee_80211_wi-fi">7.4.2. IEEE 802.11 (Wi-Fi)</a></p>

 <p class="toc_h4"><a href="#7_4_2_1_wi-fi_direct">7.4.2.1. Wi-Fi Direct</a></p>

 <p class="toc_h4"><a href="#7_4_2_2_wi-fi-tunneled-direct-link-setup">7.4.2.2. Wi-Fi Tunneled Direct Link Setup</a></p>

 <p class="toc_h3"><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></p>

 <p class="toc_h3"><a href="#7_4_4_near-field_communications">7.4.4. Near-Field Communications</a></p>

 <p class="toc_h3"><a href="#7_4_5_minimum_network_capability">7.4.5. Minimum Network Capability</a></p>

 <p class="toc_h3"><a href="#7_4_6_sync_settings">7.4.6. Sync Settings</a></p>

 <p class="toc_h2"><a href="#7_5_cameras">7.5. Cameras</a></p>

 <p class="toc_h3"><a href="#7_5_1_rear-facing_camera">7.5.1. Rear-Facing Camera</a></p>

 <p class="toc_h3"><a href="#7_5_2_front-facing_camera">7.5.2. Front-Facing Camera</a></p>

 <p class="toc_h3"><a href="#7_5_3_external_camera">7.5.3. External Camera</a></p>

 <p class="toc_h3"><a href="#7_5_4_camera_api_behavior">7.5.4. Camera API Behavior</a></p>


 </div>

 <div id="toc_right_2">

 <p class="toc_h3"><a href="#7_5_5_camera_orientation">7.5.5. Camera Orientation</a></p>

 <p class="toc_h2"><a href="#7_6_memory_and_storage">7.6. Memory and Storage</a></p>

 <p class="toc_h3"><a href="#7_6_1_minimum_memory_and_storage">7.6.1. Minimum Memory and Storage</a></p>

 <p class="toc_h3"><a href="#7_6_2_application_shared_storage">7.6.2. Application Shared Storage</a></p>

 <p class="toc_h2"><a href="#7_7_usb">7.7. USB</a></p>

 <p class="toc_h2"><a href="#7_8_audio">7.8. Audio</a></p>

 <p class="toc_h3"><a href="#7_8_1_microphone">7.8.1. Microphone</a></p>

 <p class="toc_h3"><a href="#7_8_2_audio_output">7.8.2. Audio Output</a></p>

 <p class="toc_h4"><a href="#7_8_2_1_analog_audio_ports">7.8.2.1. Analog Audio Ports</a></p>

 <p class="toc_h1"><a href="#8_performance_compatibility">8. Performance Compatibility</a></p>

 <p class="toc_h2"><a href="#8_1_user_experience_consistency">8.1. User Experience Consistency</a></p>

 <p class="toc_h2"><a href="#8_2_memory_performance">8.2. Memory Performance</a></p>

 <p class="toc_h1"><a href="#9_security_model_compatibility">9. Security Model Compatibility</a></p>

 <p class="toc_h2"><a href="#9_1_permissions">9.1. Permissions</a></p>

 <p class="toc_h2"><a href="#9_2_uid_and_process_isolation">9.2. UID and Process Isolation</a></p>

 <p class="toc_h2"><a href="#9_3_filesystem_permissions">9.3. Filesystem Permissions</a></p>

 <p class="toc_h2"><a href="#9_4_alternate_execution_environments">9.4. Alternate Execution Environments</a></p>

 <p class="toc_h2"><a href="#9_5_multi-user_support">9.5. Multi-User Support</a></p>

 <p class="toc_h2"><a href="#9_6_premium_sms_warning">9.6. Premium SMS Warning</a></p>

 <p class="toc_h2"><a href="#9_7_kernel_security_features">9.7. Kernel Security Features</a></p>

 <p class="toc_h2"><a href="#9_8_privacy">9.8. Privacy</a></p>

 <p class="toc_h2"><a href="#9_9_full-disk-encryption">9.9. Full-Disk Encryption</a></p>

 <p class="toc_h2"><a href="#9_10_verified_boot">9.10. Verified Boot</a></p>

 <p class="toc_h1"><a href="#10_software_compatibility_testing">10. Software Compatibility Testing</a></p>

 <p class="toc_h2"><a href="#10_1_compatibility_test_suite">10.1. Compatibility Test Suite</a></p>

 <p class="toc_h2"><a href="#10_2_cts_verifier">10.2. CTS Verifier</a></p>

 <p class="toc_h1"><a href="#11_updatable_software">11. Updatable Software</a></p>

 <p class="toc_h1"><a href="#12_document_changelog">12. Document Changelog</a></p>

 <p class="toc_h1"><a href="#13_contact_us">13. Contact Us</a></p>

 <p class="toc_h1"><a href="#14_resources">14. Resources</a></p>

 </div>

 </div>

 <div style="clear: both"></div>

 <div id="main">

 <h1 id="1_introduction">1. Introduction</h1>


 <p>This document enumerates the requirements that must be met in order for devices
 to be compatible with Android ANDROID_VERSION.</p>

 <p>The use of &ldquo;MUST&rdquo;, &ldquo;MUST NOT&rdquo;, &ldquo;REQUIRED&rdquo;, &ldquo;SHALL&rdquo;, &ldquo;SHALL NOT&rdquo;, &ldquo;SHOULD&rdquo;,&ldquo;SHOULD NOT&rdquo;, &ldquo;RECOMMENDED&rdquo;, &ldquo;MAY&rdquo;, and &ldquo;OPTIONAL&rdquo; is per the IETF standard
 defined in RFC2119 [<a href="http://www.ietf.org/rfc/rfc2119.txt">Resources, 1</a>].</p>

 <p>As used in this document, a &ldquo;device implementer&rdquo; or &ldquo;implementer&rdquo; is a person
 or organization developing a hardware/software solution running Android ANDROID_VERSION. A
 &ldquo;device implementation&rdquo; or &ldquo;implementation is the hardware/software solution
 so developed.</p>

 <p>To be considered compatible with Android ANDROID_VERSION, device implementations MUST meet
 the requirements presented in this Compatibility Definition, including any
 documents incorporated via reference.</p>

 <p>Where this definition or the software tests described in <a href="#10_software_compatibility_testing">section 10</a> is silent, ambiguous, or incomplete, it is the responsibility of the device
 implementer to ensure compatibility with existing implementations.</p>

 <p>For this reason, the Android Open Source Project [<a href="http://source.android.com/">Resources, 2</a>] is both the reference and preferred implementation of Android. Device
 implementers are strongly encouraged to base their implementations to the
 greatest extent possible on the &ldquo;upstream&rdquo; source code available from the
 Android Open Source Project. While some components can hypothetically be
 replaced with alternate implementations this practice is strongly discouraged,
 as passing the software tests will become substantially more difficult. It is
 the implementer&rsquo;s responsibility to ensure full behavioral compatibility with
 the standard Android implementation, including and beyond the Compatibility
 Test Suite. Finally, note that certain component substitutions and
 modifications are explicitly forbidden by this document.</p>

 <p>Many of the resources listed in <a href="#14_resources">section 14</a> are derived directly or indirectly from the Android SDK, and will be
 functionally identical to the information in that SDK&rsquo;s documentation. For any
 case where this Compatibility Definition or the Compatibility Test Suite
 disagrees with the SDK documentation, the SDK documentation is considered
 authoritative. Any technical details provided in the references included in <a href="#14_resources">section 14</a> are considered by inclusion to be part of this Compatibility Definition. </p>

 <h1 id="2_device_types">2. Device Types</h1>


 <p>While the Android Open Source Project has been used in the implementation of a
 variety of device types and form factors, many aspects of the architecture and
 compatibility requirements were optimized for handheld devices. Starting from
 Android 5.0, the Android Open Source Project aims to embrace a wider variety of
 device types as described in this section.</p>

 <p><strong>Android Handheld device</strong> refers to an Android device implementation that is typically used by holding
 it in the hand, such as mp3 players, phones, and tablets. Android Handheld
 device implementations:</p>

 <ul>
   <li>MUST have a touchscreen embedded in the device.</li>
   <li>MUST have a power source that provides mobility, such as a battery.</li>
 </ul>

 <p><strong>Android Television device</strong> refers to an Android device implementation that is an entertainment interface
 for consuming digital media, movies, games, apps, and/or live TV for users
 sitting about ten feet away (a &ldquo;lean back&rdquo; or &ldquo;10-foot user interface&rdquo;).
 Android Television devices:</p>

 <ul>
   <li>MUST have an embedded screen OR include a video output port, such as VGA, HDMI,
 or a wireless port for display.</li>
   <li>MUST declare the features android.software.leanback and
 android.hardware.type.television [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK">Resources, 3</a>].</li>
 </ul>

 <p><strong>Android Watch device</strong> refers to an Android device implementation intended to be worn on the body,
 perhaps on the wrist, and:</p>

 <ul>
   <li>MUST have a screen with the physical diagonal length in the range from 1.1 to
 2.5 inches.</li>
   <li>MUST declare the feature android.hardware.type.watch.</li>
   <li>MUST support uiMode = UI_MODE_TYPE_WATCH [<a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH">Resources, 4</a>].</li>
 </ul>

 <p><strong>Android Automotive implementation</strong> refers to a vehicle head
 unit running Android as an operating system for part or all of the system and/or
 infotainment functionality. Android Automotive implementations MUST support
 uiMode = UI_MODE_TYPE_CAR [<a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR">Resources, 111</a>].</p>

 <p>All Android device implementations that do not fit into any of the above device
 types still MUST meet all requirements in this document to be Android ANDROID_VERSION
 compatible, unless the requirement is explicitly described to be only
 applicable to a specific Android device type from above.</p>

 <h2 id="2_1_device_configurations">2.1 Device Configurations</h2>


 <p>This is a summary of major differences in hardware configuration by device
 type. (Empty cells denote a &ldquo;MAY&rdquo;). Not all configurations are covered in this
 table; see relevant hardware sections for more detail.</p>
 <table>
  <tr>
     <th>Category</th>
     <th>Feature</th>
     <th>Section</th>
     <th>Handheld</th>
     <th>Television</th>
     <th>Watch</th>
     <th>Automotive</th>
     <th>Other</th>
  </tr>
  <tr>
     <td rowspan="3">Input</td>
     <td>D-pad</td>
     <td><a href="#7_2_2_non-touch-navigation">7.2.2. Non-touch Navigation</a></td>
     <td></td>
     <td>MUST</td>
     <td></td>
     <td></td>
     <td></td>
  </tr>
  <tr>
     <td>Touchscreen </td>
     <td><a href="#7_2_4_touchscreen_input">7.2.4. Touchscreen input</a></td>
     <td>MUST</td>
     <td></td>
     <td>MUST</td>
     <td></td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>Microphone </td>
     <td><a href="#7_8_1_microphone">7.8.1. Microphone</a></td>
     <td>MUST</td>
     <td>SHOULD </td>
     <td>MUST</td>
     <td>MUST</td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td rowspan="2">Sensors</td>
     <td>Accelerometer </td>
     <td><a href="#7_3_1_accelerometer">7.3.1 Accelerometer</a></td>
     <td>SHOULD</td>
     <td></td>
     <td>SHOULD</td>
     <td></td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>GPS</td>
     <td><a href="#7_3_3_gps">7.3.3. GPS</a></td>
     <td>SHOULD</td>
     <td></td>
     <td></td>
     <td>SHOULD</td>
     <td></td>
  </tr>
  <tr>
     <td rowspan="5">Connectivity</td>
     <td>Wi-Fi</td>
     <td><a href="#7_4_2_ieee_802.11">7.4.2. IEEE 802.11</a></td>
     <td>SHOULD</td>
     <td> MUST</td>
     <td></td>
     <td>SHOULD</td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>Wi-Fi Direct</td>
     <td><a href="#7_4_2_1_wi-fi-direct">7.4.2.1. Wi-Fi Direct</a></td>
     <td>SHOULD</td>
     <td>SHOULD</td>
     <td></td>
     <td></td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>Bluetooth</td>
     <td><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></td>
     <td>SHOULD</td>
     <td>MUST</td>
     <td>MUST</td>
     <td>MUST</td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>Bluetooth Low Energy</td>
     <td><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></td>
     <td>SHOULD</td>
     <td>MUST</td>
     <td>SHOULD</td>
     <td>SHOULD</td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>USB peripheral/host mode</td>
     <td><a href="#7_7_usb">7.7. USB</a></td>
     <td>SHOULD</td>
     <td></td>
     <td></td>
     <td>SHOULD</td>
     <td>SHOULD</td>
  </tr>
  <tr>
     <td>Output</td>
     <td>Speaker and/or Audio output ports</td>
     <td><a href="#7_8_2_audio_output">7.8.2. Audio Output</a></td>
     <td>MUST</td>
     <td>MUST</td>
     <td></td>
     <td>MUST</td>
     <td>MUST</td>
  </tr>
 </table>


 <h1 id="3_software">3. Software</h1>


 <h2 id="3_1_managed_api_compatibility">3.1. Managed API Compatibility</h2>


 <p>The managed Dalvik bytecode execution environment is the primary vehicle for
 Android applications. The Android application programming interface (API) is
 the set of Android platform interfaces exposed to applications running in the
 managed runtime environment. Device implementations MUST provide complete
 implementations, including all documented behaviors, of any documented API
 exposed by the Android SDK [<a href="http://developer.android.com/reference/packages.html">Resources, 5</a>] or any API decorated with the &ldquo;@SystemApi&rdquo; marker in the upstream Android
 source code. </p>

 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces or
 signatures, deviate from the documented behavior, or include no-ops, except
 where specifically allowed by this Compatibility Definition.</p>

 <p>This Compatibility Definition permits some types of hardware for which Android
 includes APIs to be omitted by device implementations. In such cases, the APIs
 MUST still be present and behave in a reasonable way. See <a href="#7_hardware_compatibility">section 7</a> for specific requirements for this scenario.</p>

 <h2 id="3_2_soft_api_compatibility">3.2. Soft API Compatibility</h2>


 <p>In addition to the managed APIs from <a href="#3_1_managed_api_compatibility">section 3.1</a>, Android also includes a significant runtime-only &ldquo;soft&rdquo; API, in the form of
 such things as intents, permissions, and similar aspects of Android
 applications that cannot be enforced at application compile time.</p>

 <h3 id="3_2_1_permissions">3.2.1. Permissions</h3>


 <p>Device implementers MUST support and enforce all permission constants as
 documented by the Permission reference page [<a href="http://developer.android.com/reference/android/Manifest.permission.html">Resources, 6]</a>. Note that <a href="#9_security_model_compatibility">section 9</a> lists additional requirements related to the Android security model.</p>

 <h3 id="3_2_2_build_parameters">3.2.2. Build Parameters</h3>


 <p>The Android APIs include a number of constants on the android.os.Build class [<a href="http://developer.android.com/reference/android/os/Build.html">Resources, 7</a>] that are intended to describe the current device. To provide consistent,
 meaningful values across device implementations, the table below includes
 additional restrictions on the formats of these values to which device
 implementations MUST conform.</p>
 <table>
  <tr>
     <th>Parameter</th>
     <th>Details</th>
  </tr>
  <tr>
     <td>VERSION.RELEASE</td>
     <td>The version of the currently-executing Android system, in human-readable
 format. This field MUST have one of the string values defined in [<a href="http://source.android.com/compatibility/ANDROID_VERSION/versions.html">Resources, 8]</a>.</td>
  </tr>
  <tr>
     <td>VERSION.SDK</td>
     <td>The version of the currently-executing Android system, in a format accessible
 to third-party application code. For Android ANDROID_VERSION, this field MUST have the
 integer value ANDROID_VERSION_INT.</td>
  </tr>
  <tr>
     <td>VERSION.SDK_INT</td>
     <td>The version of the currently-executing Android system, in a format accessible
 to third-party application code. For Android ANDROID_VERSION, this field MUST have the
 integer value ANDROID_VERSION_INT.</td>
  </tr>
  <tr>
     <td>VERSION.INCREMENTAL</td>
     <td>A value chosen by the device implementer designating the specific build of the
 currently-executing Android system, in human-readable format. This value MUST
 NOT be reused for different builds made available to end users. A typical use
 of this field is to indicate which build number or source-control change
 identifier was used to generate the build. There are no requirements on the
 specific format of this field, except that it MUST NOT be null or the empty
 string ("").</td>
  </tr>
  <tr>
     <td>BOARD</td>
     <td>A value chosen by the device implementer identifying the specific internal
 hardware used by the device, in human-readable format. A possible use of this
 field is to indicate the specific revision of the board powering the device.
 The value of this field MUST be encodable as 7-bit ASCII and match the regular
 expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
  </tr>
  <tr>
     <td>BRAND</td>
     <td>A value reflecting the brand name associated with the device as known to the
 end users. MUST be in human-readable format and SHOULD represent the
 manufacturer of the device or the company brand under which the device is
 marketed. The value of this field MUST be encodable as 7-bit ASCII and match
 the regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
  </tr>
  <tr>
     <td>SUPPORTED_ABIS</td>
     <td>The name of the instruction set (CPU type + ABI convention) of native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
  </tr>
  <tr>
     <td>SUPPORTED_32_BIT_ABIS</td>
     <td>The name of the instruction set (CPU type + ABI convention) of native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
  </tr>
  <tr>
     <td>SUPPORTED_64_BIT_ABIS</td>
     <td>The name of the second instruction set (CPU type + ABI convention) of native
 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
  </tr>
  <tr>
     <td>CPU_ABI</td>
     <td>The name of the instruction set (CPU type + ABI convention) of native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
  </tr>
  <tr>
     <td>CPU_ABI2</td>
     <td>The name of the second instruction set (CPU type + ABI convention) of native
 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
  </tr>
  <tr>
     <td>DEVICE</td>
     <td>A value chosen by the device implementer containing the development name or
 code name identifying the configuration of the hardware features and industrial
 design of the device. The value of this field MUST be encodable as 7-bit ASCII
 and match the regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
  </tr>
  <tr>
     <td>FINGERPRINT</td>
     <td>A string that uniquely identifies this build. It SHOULD be reasonably
 human-readable. It MUST follow this template:</p>

 <p class="small">$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</p>

 <p>For example: acme/myproduct/mydevice:ANDROID_VERSION/LMYXX/3359:userdebug/test-keys</p>

 <p>The fingerprint MUST NOT include whitespace characters. If other fields
 included in the template above have whitespace characters, they MUST be
 replaced in the build fingerprint with another character, such as the
 underscore ("_") character. The value of this field MUST be encodable as 7-bit
 ASCII.</td>
  </tr>
  <tr>
     <td>HARDWARE</td>
     <td>The name of the hardware (from the kernel command line or /proc). It SHOULD be
 reasonably human-readable. The value of this field MUST be encodable as 7-bit
 ASCII and match the regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;. </td>
  </tr>
  <tr>
     <td>HOST</td>
     <td>A string that uniquely identifies the host the build was built on, in
 human-readable format. There are no requirements on the specific format of this
 field, except that it MUST NOT be null or the empty string ("").</td>
  </tr>
  <tr>
     <td>ID</td>
     <td>An identifier chosen by the device implementer to refer to a specific release,
 in human-readable format. This field can be the same as
 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently
 meaningful for end users to distinguish between software builds. The value of
 this field MUST be encodable as 7-bit ASCII and match the regular expression &ldquo;^[a-zA-Z0-9._-]+$&rdquo;.</td>
  </tr>
  <tr>
     <td>MANUFACTURER</td>
     <td>The trade name of the Original Equipment Manufacturer (OEM) of the product.
 There are no requirements on the specific format of this field, except that it
 MUST NOT be null or the empty string ("").</td>
  </tr>
  <tr>
     <td>MODEL</td>
     <td>A value chosen by the device implementer containing the name of the device as
 known to the end user. This SHOULD be the same name under which the device is
 marketed and sold to end users. There are no requirements on the specific
 format of this field, except that it MUST NOT be null or the empty string ("").</td>
  </tr>
  <tr>
     <td>PRODUCT</td>
     <td>A value chosen by the device implementer containing the development name or
 code name of the specific product (SKU) that MUST be unique within the same
 brand. MUST be human-readable, but is not necessarily intended for view by end
 users. The value of this field MUST be encodable as 7-bit ASCII and match the
 regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
  </tr>
  <tr>
     <td>SERIAL</td>
     <td>A hardware serial number, which MUST be available and unique across
 devices with the same MODEL and MANUFACTURER. The value of this field MUST
 be encodable as 7-bit ASCII and match the regular expression &ldquo;^([a-zA-Z0-9]{6,20})$&rdquo;.</td>
  </tr>
  <tr>
     <td>TAGS</td>
     <td>A comma-separated list of tags chosen by the device implementer that further
 distinguishes the build. This field MUST have one of the values corresponding
 to the three typical Android platform signing configurations: release-keys,
 dev-keys, test-keys. </td>
  </tr>
  <tr>
     <td>TIME</td>
     <td>A value representing the timestamp of when the build occurred.</td>
  </tr>
  <tr>
     <td>TYPE</td>
     <td>A value chosen by the device implementer specifying the runtime configuration
 of the build. This field MUST have one of the values corresponding to the three
 typical Android runtime configurations: user, userdebug, or eng.</td>
  </tr>
  <tr>
     <td>USER</td>
     <td>A name or user ID of the user (or automated user) that generated the build.
 There are no requirements on the specific format of this field, except that it
 MUST NOT be null or the empty string ("").</td>
  </tr>
 </table>


 <h3 id="3_2_3_intent_compatibility">3.2.3. Intent Compatibility</h3>


 <p>Device implementations MUST honor Android&rsquo;s loose-coupling intent system, as
 described in the sections below. By&ldquo;honored &rdquo; it is meant that the device
 implementer MUST provide an Android Activity or Service that specifies a
 matching intent filter that binds to and implements correct behavior for each
 specified intent pattern.</p>

 <h4 id="3_2_3_1_core_application_intents">3.2.3.1. Core Application Intents</h4>


 <p>Android intents allow application components to request functionality from
 other Android components. The Android upstream project includes a list of
 applications considered core Android applications, which implements several
 intent patterns to perform common actions. The core Android applications are:</p>

 <ul>
   <li>Desk Clock</li>
   <li>Browser</li>
   <li>Calendar</li>
   <li>Contacts</li>
   <li>Gallery</li>
   <li>GlobalSearch</li>
   <li>Launcher</li>
   <li>Music</li>
   <li>Settings</li>
 </ul>

 <p>Device implementations SHOULD include the core Android applications as
 appropriate but MUST include a component implementing the same intent patterns
 defined by all the &ldquo;public&rdquo; Activity or Service components of these core
 Android applications. Note that Activity or Service components are considered
 &ldquo;public&rdquo; when the attribute android:exported is absent or has the value true.</p>

 <h4 id="3_2_3_2_intent_overrides">3.2.3.2. Intent Overrides</h4>


 <p>As Android is an extensible platform, device implementations MUST allow each
 intent pattern referenced in <a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a> to be overridden by third-party applications. The upstream Android open source
 implementation allows this by default; device implementers MUST NOT attach
 special privileges to system applications' use of these intent patterns, or
 prevent third-party applications from binding to and assuming control of these
 patterns. This prohibition specifically includes but is not limited to
 disabling the&ldquo;Chooser&rdquo; user interface that allows the user to select between
 multiple applications that all handle the same intent pattern.</p>

 <p>However, device implementations MAY provide default activities for specific URI
 patterns (eg. http://play.google.com) if the default activity provides a more
 specific filter for the data URI. For example, an intent filter specifying the
 data URI &ldquo;http://www.android.com&rdquo; is more specific than the browser filter for&ldquo;http://&rdquo;. Device implementations MUST provide a user interface for users to
 modify the default activity for intents.</p>

 <h4 id="3_2_3_3_intent_namespaces">3.2.3.3. Intent Namespaces</h4>


 <p>Device implementations MUST NOT include any Android component that honors any
 new intent or broadcast intent patterns using an ACTION, CATEGORY, or other key
 string in the android.* or com.android.* namespace. Device implementers MUST
 NOT include any Android components that honor any new intent or broadcast
 intent patterns using an ACTION, CATEGORY, or other key string in a package
 space belonging to another organization. Device implementers MUST NOT alter or
 extend any of the intent patterns used by the core apps listed in <a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>. Device implementations MAY include intent patterns using namespaces clearly
 and obviously associated with their own organization. This prohibition is
 analogous to that specified for Java language classes in <a href="#3_6_api_namespaces">section 3.6</a>.</p>

 <h4 id="3_2_3_4_broadcast_intents">3.2.3.4. Broadcast Intents</h4>


 <p>Third-party applications rely on the platform to broadcast certain intents to
 notify them of changes in the hardware or software environment.
 Android-compatible devices MUST broadcast the public broadcast intents in
 response to appropriate system events. Broadcast intents are described in the
 SDK documentation.</p>

 <h4 id="3_2_3_5_default_app_settings">3.2.3.5. Default App Settings</h4>


 <p>Android includes settings that provide users an easy way to select their
 default applications, for example for Home screen or SMS. Where it makes sense,
 device implementations MUST provide a similar settings menu and be compatible
 with the intent filter pattern and API methods described in the SDK
 documentation as below.</p>

 <p>Device implementations:</p>

 <ul>
   <li>MUST honor the android.settings.HOME_SETTINGS intent to show a default app
 settings menu for Home Screen, if the device implementation reports
 android.software.home_screen [<a href="http://developer.android.com/reference/android/provider/Settings.html">Resources, 10]</a></li>
   <li>MUST provide a settings menu that will call the
 android.provider.Telephony.ACTION_CHANGE_DEFAULT intent to show a dialog to
 change the default SMS application, if the device implementation reports
 android.hardware.telephony [<a href="http://developer.android.com/reference/android/provider/Telephony.Sms.Intents.html">Resources, 9</a>]</li>
   <li>MUST honor the android.settings.NFC_PAYMENT_SETTINGS intent to show a default
 app settings menu for Tap and Pay, if the device implementation reports
 android.hardware.nfc.hce [<a href="http://developer.android.com/reference/android/provider/Settings.html">Resources, 10]</a></li>
 </ul>

 <h2 id="3_3_native_api_compatibility">3.3. Native API Compatibility</h2>


 <h3 id="3_3_1_application_binary_interfaces">3.3.1. Application Binary Interfaces</h3>


 <p>Managed Dalvik bytecode can call into native code provided in the application
 .apk file as an ELF .so file compiled for the appropriate device hardware
 architecture. As native code is highly dependent on the underlying processor
 technology, Android defines a number of Application Binary Interfaces (ABIs) in
 the Android NDK. Device implementations MUST be compatible with one or more
 defined ABIs, and MUST implement compatibility with the Android NDK, as below.</p>

 <p>If a device implementation includes support for an Android ABI, it:</p>

 <ul>
   <li>MUST include support for code running in the managed environment to call into
 native code, using the standard Java Native Interface (JNI) semantics</li>
   <li>MUST be source-compatible (i.e. header compatible) and binary-compatible (for
 the ABI) with each required library in the list below</li>
   <li>MUST support the equivalent 32-bit ABI if any 64-bit ABI is supported</li>
   <li>MUST accurately report the native Application Binary Interface (ABI) supported
 by the device, via the android.os.Build.SUPPORTED_ABIS,
 android.os.Build.SUPPORTED_32_BIT_ABIS, and
 android.os.Build.SUPPORTED_64_BIT_ABIS parameters, each a comma separated list
 of ABIs ordered from the most to the least preferred one</li>
   <li>MUST report, via the above parameters, only those ABIs documented and
 described in the latest version of the Android NDK ABI Management documentation
 [<a href="https://developer.android.com/ndk/guides/abis.html">Resources, XX</a>],
 and MUST include support for the Advanced SIMD (a.k.a. NEON)
 [<a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html">Resources,XX</a>]
 extension
   </li>
   <li>SHOULD be built using the source code and header files available in the
 upstream Android Open Source Project</li>
 </ul>

 <p>The following native code APIs MUST be available to apps that include native
 code:</p>

 <ul>
   <li>libc (C library)</li>
   <li>libm (math library)</li>
   <li>Minimal support for C++</li>
   <li>JNI interface</li>
   <li>liblog (Android logging)</li>
   <li>libz (Zlib compression)</li>
   <li>libdl (dynamic linker)</li>
   <li>libGLESv1_CM.so (OpenGL ES 1.x)</li>
   <li>libGLESv2.so (OpenGL ES 2.0)</li>
   <li>libGLESv3.so (OpenGL ES 3.x)</li>
   <li>libEGL.so (native OpenGL surface management)</li>
   <li>libjnigraphics.so</li>
   <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li>
   <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li>
   <li>libandroid.so (native Android activity support)</li>
   <li>libmediandk.so (native media APIs support)</li>
   <li>Support for OpenGL, as described below</li>
 </ul>

 <p>Note that future releases of the Android NDK may introduce support for
 additional ABIs. If a device implementation is not compatible with an existing
 predefined ABI, it MUST NOT report support for any ABIs at all.</p>

 <p>Note that device implementations MUST include libGLESv3.so and it MUST symlink
 (symbolic link) to libGLESv2.so. in turn, MUST export all the OpenGL ES 3.1 and
 Android Extension Pack [<a href="http://developer.android.com/guide/topics/graphics/opengl.html#aep">Resources, 11</a>] function symbols as defined in the NDK release android-21. Although all the
 symbols must be present, only the corresponding functions for OpenGL ES
 versions and extensions actually supported by the device must be fully
 implemented.</p>

 <p>Native code compatibility is challenging. For this reason, device implementers
 are <strong>very strongly encouraged</strong> to use the implementations of the libraries listed above from the upstream
 Android Open Source Project. </p>

 <h3 id="3_3_2_32-bit_arm_native_code_compatibility">
 3.3.2. 32-bit ARM Native Code Compatibility
 </h3>

 <p>The ARMv8 architecture deprecates several CPU operations, including some
 operations used in existing native code.  On 64-bit ARM devices, the following
 deprecated operations MUST remain available to 32-bit native ARM code, either
 through native CPU support or through software emulation:</p>

 <ul>
 <li>SWP and SWPB instructions</li>
 <li>SETEND instruction</li>
 <li>CP15ISB, CP15DSB, and CP15DMB barrier operations</li>
 </ul>

 <p>Legacy versions of the Android NDK used /proc/cpuinfo to discover CPU features
 from 32-bit ARM native code. For compatibility with applications built using this
 NDK, devices MUST include the following lines in /proc/cpuinfo when it is read
 by 32-bit ARM applications:</p>

 <ul>
 <li>&quot;Features: &quot;, followed by a list of any optional ARMv7 CPU features
 supported by the device</li>
 <li>&quot;CPU architecture: &quot;, followed by an integer describing the device's
 highest supported ARM architecture (e.g., &quot;8&quot; for ARMv8 devices)</li>
 </ul>

 <p>These requirements only apply when /proc/cpuinfo is read by 32-bit ARM
 applications. Devices SHOULD not alter /proc/cpuinfo when read by 64-bit ARM or
 non-ARM applications.</p>

 <h2 id="3_4_web_compatibility">3.4. Web Compatibility</h2>


 <h3 id="3_4_1_webview_compatibility">3.4.1. WebView Compatibility</h3>

 <div class="note">
 <p>Android Watch devices MAY, but all other device implementations MUST provide
 a complete implementation of the android.webkit.Webview API.</p>
 </div>


 <p>The platform feature android.software.webview MUST be reported on any device
 that provides a complete implementation of the android.webkit.WebView API, and
 MUST NOT be reported on devices without a complete implementation of the API.
 The Android Open Source implementation uses code from the Chromium Project to
 implement the android.webkit.WebView [<a href="http://developer.android.com/reference/android/webkit/WebView.html">Resources, 12</a>]. Because it is not feasible to develop a comprehensive test suite for a web
 rendering system, device implementers MUST use the specific upstream build of
 Chromium in the WebView implementation. Specifically:</p>

 <ul>
   <li>Device android.webkit.WebView implementations MUST be based on the Chromium
 build from the upstream Android Open Source Project for Android ANDROID_VERSION. This build
 includes a specific set of functionality and security fixes for the WebView [<a href="http://www.chromium.org/">Resources, 13</a>].</li>
   <li>The user agent string reported by the WebView MUST be in this format:
 <p>Mozilla/5.0 (Linux; Android $(VERSION); $(MODEL) Build/$(BUILD); wv)
 AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 $(CHROMIUM_VER) Mobile
 Safari/537.36</p>
   <ul>
     <li>The value of the $(VERSION) string MUST be the same as the value for
 android.os.Build.VERSION.RELEASE.</li>
     <li>The value of the $(MODEL) string MUST be the same as the value for
 android.os.Build.MODEL.</li>
     <li>The value of the $(BUILD) string MUST be the same as the value for
 android.os.Build.ID.</li>
     <li>The value of the $(CHROMIUM_VER) string MUST be the version of Chromium in the
 upstream Android Open Source Project.</li>
     <li>Device implementations MAY omit Mobile in the user agent string.</li>
   </ul></li></ul>

 <p>The WebView component SHOULD include support for as many HTML5 features as
 possible and if it supports the feature SHOULD conform to the HTML5
 specification [<a href="http://html.spec.whatwg.org/multipage/">Resources, 14</a>].</p>

 <h3 id="3_4_2_browser_compatibility">3.4.2. Browser Compatibility</h3>

 <div class="note">
 <p>Android Television, Watch, and Android Automotive implementations MAY omit a
 browser application, but MUST support the public intent patterns as described in
 <a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>. All other types
 of device implementations MUST include a standalone Browser application for
 general user web browsing.</p>
 </div>

 <p>The standalone Browser MAY be based on a browser technology other than WebKit.
 However, even if an alternate Browser application is used, the
 android.webkit.WebView component provided to third-party applications MUST be
 based on WebKit, as described in <a href="#3_4_1_webview_compatibility">section 3.4.1</a>.</p>

 <p>Implementations MAY ship a custom user agent string in the standalone Browser
 application.</p>

 <p>The standalone Browser application (whether based on the upstream WebKit
 Browser application or a third-party replacement) SHOULD include support for as
 much of HTML5 [<a href="http://html.spec.whatwg.org/multipage/">Resources, 14</a>] as possible. Minimally, device implementations MUST support each of these
 APIs associated with HTML5:</p>

 <ul>
   <li>application cache/offline operation [<a href="http://www.w3.org/html/wg/drafts/html/master/browsers.html#offline">Resources, 15</a>]</li>
   <li>the &#60;video&#62; tag [<a href="http://www.w3.org/html/wg/drafts/html/master/semantics.html#video">Resources, 16</a>]</li>
   <li>geolocation [<a href="http://www.w3.org/TR/geolocation-API/">Resources, 17</a>]</li>
 </ul>

 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage API
 [<a href="http://www.w3.org/TR/webstorage/">Resources, 18</a>], and SHOULD support the HTML5/W3C IndexedDB API [<a href="http://www.w3.org/TR/IndexedDB/">Resources, 19</a>]. Note that as the web development standards bodies are transitioning to favor
 IndexedDB over webstorage, IndexedDB is expected to become a required component
 in a future version of Android.</p>

 <h2 id="3_5_api_behavioral_compatibility">3.5. API Behavioral Compatibility</h2>


 <p>The behaviors of each of the API types (managed, soft, native, and web) must be
 consistent with the preferred implementation of the upstream Android Open
 Source Project [<a href="http://source.android.com/">Resources, 2</a>]. Some specific areas of compatibility are:</p>

 <ul>
   <li>Devices MUST NOT change the behavior or semantics of a standard intent.</li>
   <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular
 type of system component (such as Service, Activity, ContentProvider, etc.).</li>
   <li>Devices MUST NOT change the semantics of a standard permission.</li>
 </ul>

 <p>The above list is not comprehensive. The Compatibility Test Suite (CTS) tests
 significant portions of the platform for behavioral compatibility, but not all.
 It is the responsibility of the implementer to ensure behavioral compatibility
 with the Android Open Source Project. For this reason, device implementers
 SHOULD use the source code available via the Android Open Source Project where
 possible, rather than re-implement significant parts of the system.</p>

 <h2 id="3_6_api_namespaces">3.6. API Namespaces</h2>


 <p>Android follows the package and class namespace conventions defined by the Java
 programming language. To ensure compatibility with third-party applications,
 device implementers MUST NOT make any prohibited modifications (see below) to
 these package namespaces:</p>

 <ul>
   <li>java.*</li>
   <li>javax.*</li>
   <li>sun.*</li>
   <li>android.*</li>
   <li>com.android.*</li>
 </ul>

 <p><strong>Prohibited modifications include</strong>:</p>

 <ul>
   <li>Device implementations MUST NOT modify the publicly exposed APIs on the Android
 platform by changing any method or class signatures, or by removing classes or
 class fields.</li>
   <li>Device implementers MAY modify the underlying implementation of the APIs, but
 such modifications MUST NOT impact the stated behavior and Java-language
 signature of any publicly exposed APIs.</li>
   <li>Device implementers MUST NOT add any publicly exposed elements (such as classes
 or interfaces, or fields or methods to existing classes or interfaces) to the
 APIs above.</li>
 </ul>

 <p>A &ldquo;publicly exposed element&rdquo; is any construct which is not decorated with the&ldquo;@hide&rdquo; marker as used in the upstream Android source code. In other words,
 device implementers MUST NOT expose new APIs or alter existing APIs in the
 namespaces noted above. Device implementers MAY make internal-only
 modifications, but those modifications MUST NOT be advertised or otherwise
 exposed to developers.</p>

 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a
 namespace owned by or referring to another organization. For instance, device
 implementers MUST NOT add APIs to the com.google.* or similar namespace: only
 Google may do so. Similarly, Google MUST NOT add APIs to other companies'
 namespaces. Additionally, if a device implementation includes custom APIs
 outside the standard Android namespace, those APIs MUST be packaged in an
 Android shared library so that only apps that explicitly use them (via the
 lt;uses-librarygt; mechanism) are affected by the increased memory usage of such
 APIs.</p>

 <p>If a device implementer proposes to improve one of the package namespaces above
 (such as by adding useful new functionality to an existing API, or adding a new
 API), the implementer SHOULD visit <a href="http://source.android.com/">source.android.com</a> and begin the process for contributing changes and code, according to the
 information on that site.</p>

 <p>Note that the restrictions above correspond to standard conventions for naming
 APIs in the Java programming language; this section simply aims to reinforce
 those conventions and make them binding through inclusion in this Compatibility
 Definition.</p>

 <h2 id="3_7_runtime_compatibility">3.7. Runtime Compatibility</h2>


 <p>Device implementations MUST support the full Dalvik Executable (DEX) format and
 Dalvik bytecode specification and semantics [<a href="https://android.googlesource.com/platform/dalvik/+/lollipop-release/docs/">Resources, 20</a>]. Device implementers SHOULD use ART, the reference upstream implementation of
 the Dalvik Executable Format, and the reference implementation&rsquo;s package
 management system.</p>

 <p>Device implementations MUST configure Dalvik runtimes to allocate memory in
 accordance with the upstream Android platform, and as specified by the
 following table. (See <a href="#7_1_1_screen_configuration">section 7.1.1</a> for screen size and screen density definitions.)</p>

 <p>Note that memory values specified below are considered minimum values and
 device implementations MAY allocate more memory per application.</p>

 <table>
  <tr>
     <th>Screen Layout</th>
     <th>Screen Density</th>
     <th>Minimum Application Memory</th>
  </tr>
  <tr>
     <td rowspan="10">small/normal</td>
     <td>120 dpi (ldpi)</td>
     <td rowspan="2">32MB</td>
  </tr>
  <tr>
     <td>160 dpi (mdpi)</td>
  </tr>
  <tr>
     <td>213 dpi (tvdpi)</td>
     <td rowspan="3">48MB</td>
  </tr>
  <tr>
     <td>240 dpi (hdpi)</td>
  </tr>
  <tr>
     <td>280 dpi (280dpi)</td>
  </tr>
  <tr>
     <td>320 dpi (xhdpi)</td>
     <td>80MB</td>
  </tr>
  <tr>
     <td>400 dpi (400dpi)</td>
     <td>96MB</td>
  </tr>
  <tr>
     <td>480 dpi (xxhdpi)</td>
     <td>128MB</td>
  </tr>
  <tr>
     <td>560 dpi (560dpi)</td>
     <td>192MB</td>
  </tr>
  <tr>
     <td>640 dpi (xxxhdpi)</td>
     <td>256MB</td>
  </tr>
  <tr>
     <td rowspan="10">large</td>
     <td>120 dpi (ldpi)</td>
     <td>32MB</td>
  </tr>
  <tr>
     <td>160 dpi (mdpi)</td>
     <td>48MB</td>
  </tr>
  <tr>
     <td>213 dpi (tvdpi)</td>
     <td rowspan="2">80MB</td>
  </tr>
  <tr>
     <td>240 dpi (hdpi)</td>
  </tr>
  <tr>
     <td>280 dpi (280dpi)</td>
     <td>96MB</td>
  </tr>
  <tr>
     <td>320 dpi (xhdpi)</td>
     <td>128MB</td>
  </tr>
  <tr>
     <td>400 dpi (400dpi)</td>
     <td>192MB</td>
  </tr>
  <tr>
     <td>480 dpi (xxhdpi)</td>
     <td>256MB</td>
  </tr>
  <tr>
     <td>560 dpi (560dpi)</td>
     <td>384MB</td>
  </tr>
  <tr>
     <td>640 dpi (xxxhdpi)</td>
     <td>512MB</td>
  </tr>
  <tr>
     <td rowspan="10">xlarge</td>
     <td>120 dpi (ldpi)</td>
     <td>48MB</td>
  </tr>
  <tr>
     <td>160 dpi (mdpi)</td>
     <td>80MB</td>
  </tr>
  <tr>
     <td>213 dpi (tvdpi)</td>
     <td rowspan="2">96MB</td>
  </tr>
  <tr>
     <td>240 dpi (hdpi)</td>
  </tr>
  <tr>
     <td>280 dpi (280dpi)</td>
     <td>144MB</td>
  </tr>
  <tr>
     <td>320 dpi (xhdpi)</td>
     <td>192MB</td>
  </tr>
  <tr>
     <td>400 dpi (400dpi)</td>
     <td>288MB</td>
  </tr>
  <tr>
     <td>480 dpi (xxhdpi)</td>
     <td>384MB</td>
  </tr>
  <tr>
     <td>560 dpi (560dpi)</td>
     <td>576MB</td>
  </tr>
  <tr>
     <td>640 dpi (xxxhdpi)</td>
     <td>768MB</td>
  </tr>
 </table>


 <h2 id="3_8_user_interface_compatibility">3.8. User Interface Compatibility</h2>


 <h3 id="3_8_1_launcher_home_screen">3.8.1. Launcher (Home Screen)</h3>


 <p>Android includes a launcher application (home screen) and support for
 third-party applications to replace the device launcher (home screen). Device
 implementations that allow third-party applications to replace the device home
 screen MUST declare the platform feature android.software.home_screen.</p>

 <h3 id="3_8_2_widgets">3.8.2. Widgets</h3>

 <div class="note">
 <p>Widgets are optional for all Android device implementations, but SHOULD be
 supported on Android Handheld devices.</p>
 </div>


 <p>Android defines a component type and corresponding API and lifecycle that
 allows applications to expose an &ldquo;AppWidget&rdquo; to the end user [<a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">Resources, 21</a>] a feature that is strongly RECOMMENDED to be supported on Handheld Device
 implementations. Device implementations that support embedding widgets on the
 home screen MUST meet the following requirements and declare support for
 platform feature android.software.app_widgets.</p>

 <ul>
   <li>Device launchers MUST include built-in support for AppWidgets, and expose user
 interface affordances to add, configure, view, and remove AppWidgets directly
 within the Launcher.</li>
   <li>Device implementations MUST be capable of rendering widgets that are 4 x 4 in
 the standard grid size. See the App Widget Design Guidelines in the Android SDK
 documentation [<a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">Resources, 21</a>] for details.</li>
   <li>Device implementations that include support for lock screen MAY support
 application widgets on the lock screen.</li>
 </ul>

 <h3 id="3_8_3_notifications">3.8.3. Notifications</h3>


 <p>Android includes APIs that allow developers to notify users of notable events [<a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">Resources, 22</a>], using hardware and software features of the device.</p>

 <p>Some APIs allow applications to perform notifications or attract attention
 using hardware&#8212;specifically sound, vibration, and light. Device implementations
 MUST support notifications that use hardware features, as described in the SDK
 documentation, and to the extent possible with the device implementation
 hardware. For instance, if a device implementation includes a vibrator, it MUST
 correctly implement the vibration APIs. If a device implementation lacks
 hardware, the corresponding APIs MUST be implemented as no-ops. This behavior
 is further detailed in <a href="#7_hardware_compatibility">section 7</a>.</p>

 <p>Additionally, the implementation MUST correctly render all resources (icons, animation files
 etc.) provided for in the APIs
 [<a href="https://developer.android.com/guide/topics/resources/available-resources.html">Resources, 23</a>],
 or in the Status/System Bar icon style guide
 [<a href="http://developer.android.com/design/style/iconography.html">Resources, 24</a>],
 which in the case of an Android Television device includes the possibility to not display the
 notifications. Device implementers MAY provide an alternative user experience for
 notifications than that provided by the reference Android Open Source
 implementation; however, such alternative notification systems MUST support
 existing notification resources, as above. </p>

 <p>Android includes support for various notifications, such as:</p>

 <ul>
   <li><strong>Rich notifications</strong>. Interactive Views for ongoing notifications.</li>
   <li><strong>Heads-up notifications</strong>. Interactive Views users can act on or dismiss without leaving the current app.</li>
   <li><strong>Lockscreen notifications</strong>. Notifications shown over a lock screen with granular control on visibility.</li>
 </ul>

 <p>Android device implementations, when such notifications are made visible, MUST properly execute
 Rich and Heads-up notifications and include the title/name, icon, text as documented in the Android
 APIs <a href="https://developer.android.com/design/patterns/notifications.html">[Resources, 25]</a>.
 </p>

 <p>Android includes Notification Listener Service APIs that allow apps (once
 explicitly enabled by the user) to receive a copy of all notifications as they
 are posted or updated. Device implementations MUST correctly and promptly send
 notifications in their entirety to all such installed and user-enabled listener
 services, including any and all metadata attached to the Notification object.</p>

 <h3 id="3_8_4_search">3.8.4. Search</h3>


 <p>Android includes APIs [<a href="http://developer.android.com/reference/android/app/SearchManager.html">Resources, 26</a>] that allow developers to incorporate search into their applications, and
 expose their application&rsquo;s data into the global system search. Generally
 speaking, this functionality consists of a single, system-wide user interface
 that allows users to enter queries, displays suggestions as users type, and
 displays results. The Android APIs allow developers to reuse this interface to
 provide search within their own apps, and allow developers to supply results to
 the common global search user interface.</p>

 <p>Android device implementations SHOULD include global search, a single, shared,
 system-wide search user interface capable of real-time suggestions in response
 to user input. Device implementations SHOULD implement the APIs that allow
 developers to reuse this user interface to provide search within their own
 applications. Device implementations that implement the global search interface
 MUST implement the APIs that allow third-party applications to add suggestions
 to the search box when it is run in global search mode. If no third-party
 applications are installed that make use of this functionality, the default
 behavior SHOULD be to display web search engine results and suggestions.</p>

 <h3 id="3_8_5_toasts">3.8.5. Toasts</h3>


 <p>Applications can use the &ldquo;Toast&rdquo; API to display short non-modal strings to the
 end user, that disappear after a brief period of time [<a href="http://developer.android.com/reference/android/widget/Toast.html">Resources, 27</a>]. Device implementations MUST display Toasts from applications to end users in
 some high-visibility manner.</p>

 <h3 id="3_8_6_themes">3.8.6. Themes</h3>


 <p>Android provides &ldquo;themes&rdquo; as a mechanism for applications to apply styles
 across an entire Activity or application.</p>

 <p>Android includes a &ldquo;Holo&rdquo; theme family as a set of defined styles for
 application developers to use if they want to match the Holo theme look and
 feel as defined by the Android SDK [<a href="http://developer.android.com/guide/topics/ui/themes.html">Resources, 28</a>]. Device implementations MUST NOT alter any of the Holo theme attributes
 exposed to applications [<a href="http://developer.android.com/reference/android/R.style.html">Resources, 29</a>].</p>

 <p>Android includes a &ldquo;Material&rdquo; theme family as a set of defined styles for
 application developers to use if they want to match the design theme&rsquo;s look and
 feel across the wide variety of different Android device types. Device
 implementations MUST support the &ldquo;Material&rdquo; theme family and MUST NOT alter any
 of the Material theme attributes or their assets exposed to applications [<a href="http://developer.android.com/reference/android/R.style.html#Theme_Material">Resources, 30</a>].</p>

 <p>Android also includes a &ldquo;Device Default&rdquo; theme family as a set of defined
 styles for application developers to use if they want to match the look and
 feel of the device theme as defined by the device implementer. Device
 implementations MAY modify the Device Default theme attributes exposed to
 applications [<a href="http://developer.android.com/reference/android/R.style.html">Resources, 29</a>].</p>

 <p>Android supports a new variant theme with translucent system bars, which allows
 application developers to fill the area behind the status and navigation bar
 with their app content. To enable a consistent developer experience in this
 configuration, it is important the status bar icon style is maintained across
 different device implementations. Therefore, Android device implementations
 MUST use white for system status icons (such as signal strength and battery
 level) and notifications issued by the system, unless the icon is indicating a
 problematic status [<a href="http://developer.android.com/reference/android/R.style.html">Resources, 29</a>].</p>

 <h3 id="3_8_7_live_wallpapers">3.8.7. Live Wallpapers</h3>


 <p>Android defines a component type and corresponding API and lifecycle that
 allows applications to expose one or more &ldquo;Live Wallpapers&rdquo; to the end user [<a href="http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html">Resources, 31</a>]. Live wallpapers are animations, patterns, or similar images with limited
 input capabilities that display as a wallpaper, behind other applications.</p>

 <p>Hardware is considered capable of reliably running live wallpapers if it can
 run all live wallpapers, with no limitations on functionality, at a reasonable
 frame rate with no adverse effects on other applications. If limitations in the
 hardware cause wallpapers and/or applications to crash, malfunction, consume
 excessive CPU or battery power, or run at unacceptably low frame rates, the
 hardware is considered incapable of running live wallpaper. As an example, some
 live wallpapers may use an OpenGL 2.0 or 3.x context to render their content.
 Live wallpaper will not run reliably on hardware that does not support multiple
 OpenGL contexts because the live wallpaper use of an OpenGL context may
 conflict with other applications that also use an OpenGL context.</p>

 <p>Device implementations capable of running live wallpapers reliably as described
 above SHOULD implement live wallpapers, and when implemented MUST report the
 platform feature flag android.software.live_wallpaper.</p>

 <h3 id="3_8_8_activity_switching">3.8.8. Activity Switching</h3>

 <div class="note">
 <p>As the Recent function navigation key is OPTIONAL, the requirements to
 implement the overview screen is OPTIONAL for Android Television devices and
 Android Watch devices.</p>
 </div>


 <p>The upstream Android source code includes the overview screen [<a href="http://developer.android.com/guide/components/recents.html">Resources, 32</a>], a system-level user interface for task switching and displaying recently
 accessed activities and tasks using a thumbnail image of the application&rsquo;s
 graphical state at the moment the user last left the application. Device
 implementations including the recents function navigation key as detailed in <a href="#7_2_3_navigation_keys">section 7.2.3</a>, MAY alter the interface but MUST meet the following requirements:</p>

 <ul>
   <li>MUST display affiliated recents as a group that moves together.</li>
   <li>MUST support at least up to 20 displayed activities.</li>
   <li>MUST at least display the title of 4 activities at a time.</li>
   <li>SHOULD display highlight color, icon, screen title in recents.</li>
   <li>MUST implement the screen pinning behavior [<a href="http://developer.android.com/about/versions/android-5.0.html#ScreenPinning">Resources, 33</a>] and provide the user with a settings menu to toggle the feature.</li>
   <li>SHOULD display a closing affordance ("x") but MAY delay this until user
 interacts with screens.</li>
 </ul>

 <p>Device implementations are STRONGLY ENCOURAGED to use the upstream Android user
 interface (or a similar thumbnail-based interface) for the overview screen.</p>

 <h3 id="3_8_9_input_management">3.8.9. Input Management</h3>


 <p>Android includes support for Input Management and support for third-party input
 method editors [<a href="http://developer.android.com/guide/topics/text/creating-input-method.html">Resources, 34</a>]. Device implementations that allow users to use third-party input methods on
 the device MUST declare the platform feature android.software.input_methods and
 support IME APIs as defined in the Android SDK documentation.</p>

 <p>Device implementations that declare the android.software.input_methods feature
 MUST provide a user-accessible mechanism to add and configure third-party input
 methods. Device implementations MUST display the settings interface in response
 to the android.settings.INPUT_METHOD_SETTINGS intent.</p>

 <h3 id="3_8_10_lock_screen_media_control">3.8.10. Lock Screen Media Control</h3>


 <p>The Remote Control Client API is deprecated from Android 5.0 in favor of the
 Media Notification Template that allows media applications to integrate with
 playback controls that are displayed on the lock screen [<a href="http://developer.android.com/reference/android/app/Notification.MediaStyle.html">Resources, 35</a>].
 Device implementations that support a lock screen, unless an Android Automotive or Watch
 implementation, MUST display the Lockscreen Notifications including the Media Notification
 Template.</p>

 <h3 id="3_8_11_dreams">3.8.11. Dreams</h3>


 <p>Android includes support for interactive screensavers called Dreams [<a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">Resources, 36</a>]. Dreams allows users to interact with applications when a device connected to
 a power source is idle or docked in a desk dock. Android Watch devices MAY
 implement Dreams, but other types of device implementations SHOULD include
 support for Dreams and provide a settings option for users to configure Dreams
 in response to the android.settings.DREAM_SETTINGS intent.</p>

 <h3 id="3_8_12_location">3.8.12. Location</h3>


 <p>When a device has a hardware sensor (e.g. GPS) that is capable of providing the
 location coordinates, location modes MUST be displayed in the Location menu
 within Settings [<a href="http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE">Resources, 37</a>].</p>

 <h3 id="3_8_13_unicode_and_font">3.8.13. Unicode and Font</h3>


 <p>Android includes support for color emoji characters. When Android device
 implementations include an IME, devices SHOULD provide an input method to the
 user for the Emoji characters defined in Unicode 6.1 [<a href="http://www.unicode.org/versions/Unicode6.1.0/">Resources, 38</a>]. All devices MUST be capable of rendering these emoji characters in color glyph.</p>

 <p>Android includes support for Roboto 2 font with different
 weights&mdash;sans-serif-thin, sans-serif-light, sans-serif-medium, sans-serif-black,
 sans-serif-condensed, sans-serif-condensed-light&mdash;which MUST all be included for
 the languages available on the device and full Unicode 7.0 coverage of Latin,
 Greek, and Cyrillic, including the Latin Extended A, B, C, and D ranges, and
 all glyphs in the currency symbols block of Unicode 7.0.</p>

 <h2 id="3_9_device_administration">3.9. Device Administration</h2>

 <p>Android includes features that allow security-aware applications to perform
 device administration functions at the system level, such as enforcing password
 policies or performing remote wipe, through the Android Device Administration
 API [<a href="http://developer.android.com/guide/topics/admin/device-admin.html">Resources, 39</a>].
 Device implementations MUST provide an implementation of the DevicePolicyManager class
 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">Resources, 40</a>].
 Device implementations that include support for PIN (numeric) or PASSWORD
 (alphanumeric) based lock screens MUST support the full range of device
 administration policies defined in the Android SDK documentation
 [<a href="http://developer.android.com/guide/topics/admin/device-admin.html">Resources, 39</a>]
 and report the platform feature android.software.device_admin.</p>

 <h3 id="3_9_1_device_provisioning">3.9.1 Device Provisioning</h3>
 <h4 id="3_9_1_1_device_owner_provisioning">3.9.1.1 Device owner provisioning</h4>
 <p>If a device implementation declares the android.software.device_admin feature,
 the out of box setup flow MUST make it possible to enroll a Device Policy
 Controller (DPC) application as the Device Owner app
 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)">
 Resources, XX</a>]. Device implementations MAY have a preinstalled application
 performing device administration functions but this application MUST NOT be set
 as the Device Owner app without explicit consent or action from the user or the
 administrator of the device.</p>

 <p>The device owner provisioning process (the flow initiated by
 android.app.action.PROVISION_MANAGED_DEVICE
 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE">
 Resources, XX</a>]) user experience MUST align with the AOSP implementation</p>

 <p>If the device implementation reports android.hardware.nfc, it MUST have NFC
 enabled, even during the out-of-box setup flow, in order to allow for NFC
 provisioning of Device owners
 <a href="https://source.android.com/devices/tech/admin/provision.html#device_owner_provisioning_via_nfc">[Resources, XX]</a>.
 </p>

 <h4 id="3_9_1_2_managed_profile_provisioning">3.9.1.2 Managed profile provisioning</h4>
 <p>If a device implementation declares the android.software.managed_users,
 it MUST be possible to enroll a Device Policy Controller (DPC) application
 as the owner of a new Managed Profile
 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)">
 Resources, XX</a>]</p>

 <p>The managed profile provisioning process (the flow initiated by
 android.app.action.PROVISION_MANAGED_PROFILE
 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE">
 Resources, XX</a>]) user experience MUST align with the AOSP implementation
 </p>

 <h2 id="3_10_accessibility">3.10. Accessibility</h2>


 <p>Android provides an accessibility layer that helps users with disabilities to
 navigate their devices more easily. In addition, Android provides platform APIs
 that enable accessibility service implementations to receive callbacks for user
 and system events and generate alternate feedback mechanisms, such as
 text-to-speech, haptic feedback, and trackball/d-pad navigation [<a href="http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html">Resources, 42</a>].</p>

 <p>Device implementations include the following requirements:</p>

 <ul>
 <li>Android Automotive implementations SHOULD provide an implementation of the
 Android accessibility framework consistent with the default Android
 implementation.</li>
 <li>Device implementations (Android Automotive excluded) MUST provide an
 implementation of the Android accessibility framework consistent with the
 default Android implementation.</li>
 <li>Device implementations (Android Automotive excluded) MUST support
 third-party accessibility service implementations through the
 android.accessibilityservice APIs
 [<a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">Resources, 43</a>]</li>
 <li>Device implementations (Android Automotive excluded) MUST generate
 AccessibilityEvents and deliver these events to all registered
 AccessibilityService implementations in a manner consistent with the default
 Android implementation</li>
 <li> Device implementations (Android Automotive and Android Watch devices with
 no audio output excluded), MUST provide a user-accessible mechanism to enable
 and disable accessibility services, and MUST display this interface in response
 to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS intent.</li>
 </ul>

 <p>Additionally, device implementations SHOULD provide an implementation of an
 accessibility service on the device, and SHOULD provide a mechanism for users
 to enable the accessibility service during device setup. An open source
 implementation of an accessibility service is available from the Eyes Free
 project [<a href="http://code.google.com/p/eyes-free/">Resources, 44</a>].</p>

 <h2 id="3_11_text-to-speech">3.11. Text-to-Speech</h2>


 <p>Android includes APIs that allow applications to make use of text-to-speech
 (TTS) services and allows service providers to provide implementations of TTS
 services [<a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">Resources, 45</a>]. Device implementations reporting the feature android.hardware.audio.output
 MUST meet these requirements related to the Android TTS framework. </p>

 <p>Android Automotive implementations:</p>
 <ul>
 <li>MUST support the Android TTS framework APIs.</li>
 <li>MAY support installation of third-party TTS engines. If supported, partners
 MUST provide a user-accessible interface that allows the user to select a TTS
 engine for use at system level.</li>
 </ul>

 <p>All other device implementations:</p>

 <ul>
   <li> MUST support the Android TTS framework APIs and SHOULD include a TTS engine
 supporting the languages available on the device. Note that the upstream
 Android open source software includes a full-featured TTS engine
 implementation.
   <li> MUST support installation of third-party TTS engines
   <li> MUST provide a user-accessible interface that allows users to select a TTS
 engine for use at the system level
 </ul>

 <h2 id="3_12_tv_input_framework">3.12. TV Input Framework</h2>


 <p>The Android Television Input Framework (TIF) simplifies the delivery of live
 content to Android Television devices. TIF provides a standard API to create
 input modules that control Android Television devices. Android Television
 device implementations MUST support Television Input Framework [<a href="http://source.android.com/devices/tv/index.html">Resources, 46</a>].</p>

 <p>Device implementations that support TIF MUST declare the platform feature
 android.software.live_tv.</p>

 <h1 id="4_application_packaging_compatibility">4. Application Packaging Compatibility</h1>


 <p>Device implementations MUST install and run Android &ldquo;.apk&rdquo; files as generated
 by the &ldquo;aapt&rdquo; tool included in the official Android SDK [<a href="http://developer.android.com/tools/help/index.html">Resources, 47</a>].</p>

 <p>Devices implementations MUST NOT extend either the .apk [<a href="http://developer.android.com/guide/components/fundamentals.html">Resources, 48</a>], Android Manifest [<a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">Resources, 49</a>], Dalvik bytecode [<a href="https://android.googlesource.com/platform/dalvik/+/lollipop-release/docs/">Resources, 20</a>], or RenderScript bytecode formats in such a way that would prevent those
 files from installing and running correctly on other compatible devices.</p>

 <h1 id="5_multimedia_compatibility">5. Multimedia Compatibility</h1>


 <h2 id="5_1_media_codecs">5.1. Media Codecs</h2>


 <p>Device implementations MUST support the core media formats specified in the
 Android SDK documentation [<a href="http://developer.android.com/guide/appendix/media-formats.html">Resources, 50</a>] except where explicitly permitted in this document. Specifically, device
 implementations MUST support the media formats, encoders, decoders, file types,
 and container formats defined in the tables below and reported via MediaCodecList
 [<a href="http://developer.android.com/reference/android/media/MediaCodecList.html">Resources,112</a>].
 Device implementations MUST also be able to decode all profiles reported in its CamcorderProfile
 [<a href="http://developer.android.com/reference/android/media/CamcorderProfile.html">Resources,
 113</a>].

 All of these codecs are
 provided as software implementations in the preferred Android implementation
 from the Android Open Source Project.</p>

 <p>Please note that neither Google nor the Open Handset Alliance make any
 representation that these codecs are free from third-party patents. Those
 intending to use this source code in hardware or software products are advised
 that implementations of this code, including in open source software or
 shareware, may require patent licenses from the relevant patent holders.</p>

 <h3 id="5_1_1_audio_codecs">5.1.1. Audio Codecs</h3>

 <table>
  <tr>
     <th>Format/Codec</th>
     <th>Encoder</th>
     <th>Decoder</th>
     <th>Details</th>
     <th>Supported File Types/Container Formats</th>
  </tr>
  <tr>
     <td>MPEG-4 AAC Profile</p>

 <p>(AAC LC)</td>
     <td>REQUIRED<sup>1</sup></td>
     <td>REQUIRED</td>
     <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard sampling rates from 8 to
 48 kHz.</td>
     <td>
     <ul>
     <li class="table_list">3GPP (.3gp)</li>
     <li class="table_list">MPEG-4 (.mp4, .m4a)</li>
     <li class="table_list">ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not
 supported)</li>
     <li class="table_list">MPEG-TS (.ts, not seekable, Android 3.0+)</li></ul></td>
  </tr>
  <tr>
     <td>MPEG-4 HE AAC Profile (AAC+)</td>
     <td>REQUIRED<sup>1</sup><br>(Android 4.1+)</td>
     <td>REQUIRED</td>
     <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard sampling rates from 16
 to 48 kHz.</td>
     <td></td>
  </tr>
  <tr>
     <td>MPEG-4 HE AACv2</p>

 <p>Profile (enhanced AAC+)</td>
     <td> </td>
     <td>REQUIRED</td>
     <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard sampling rates from 16
 to 48 kHz.</td>
     <td></td>
  </tr>
  <tr>
     <td>AAC ELD (enhanced low delay AAC)</td>
     <td>REQUIRED<sup>1</sup> </p>

 <p>(Android 4.1+)</td>
     <td>REQUIRED</p>

 <p>(Android 4.1+)</td>
     <td>Support for mono/stereo content with standard sampling rates from 16 to 48 kHz.</td>
     <td></td>
  </tr>
  <tr>
     <td>AMR-NB</td>
     <td>REQUIRED<sup>3</sup></td>
     <td>REQUIRED<sup>3</sup></td>
     <td>4.75 to 12.2 kbps sampled @ 8kHz</td>
     <td>3GPP (.3gp)</td>
  </tr>
  <tr>
     <td>AMR-WB</td>
     <td>REQUIRED<sup>3</sup></td>
     <td>REQUIRED<sup>3</sup></td>
     <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td>
     <td></td>
  </tr>
  <tr>
     <td>FLAC</td>
     <td></td>
     <td>REQUIRED <br>(Android 3.1+)</td>
     <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 kHz is
 recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz downsampler
 does not include a low-pass filter). 16-bit recommended; no dither applied for
 24-bit.</td>
     <td>FLAC (.flac) only</td>
  </tr>
  <tr>
     <td>MP3</td>
     <td></td>
     <td>REQUIRED</td>
     <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bitrate (VBR)</td>
     <td>MP3 (.mp3)</td>
  </tr>
  <tr>
     <td>MIDI</td>
     <td></td>
     <td>REQUIRED</td>
     <td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for
 ringtone formats RTTTL/RTX, OTA, and iMelody</td>
     <td><ul>
     <li class="table_list">Type 0 and 1 (.mid, .xmf, .mxmf)</li>
     <li class="table_list">RTTTL/RTX (.rtttl, .rtx)</li>
     <li class="table_list">OTA (.ota)</li>
     <li class="table_list">iMelody (.imy)</li></ul></td>
  </tr>
  <tr>
     <td>Vorbis</td>
     <td></td>
     <td>REQUIRED</td>
     <td></td>
     <td><ul>
     <li class="table_list">Ogg (.ogg)</li>
     <li class="table_list">Matroska (.mkv, Android 4.0+)</li></ul></td>
  </tr>
  <tr>
     <td>PCM/WAVE</td>
     <td>REQUIRED<sup>4</sup><br> (Android 4.1+)</td>
     <td>REQUIRED</td>
     <td>16-bit linear PCM (rates up to limit of hardware). Devices MUST support
 sampling rates for raw PCM recording at 8000, 11025, 16000, and 44100 Hz
 frequencies.</td>
     <td>WAVE (.wav)</td>
  </tr>
  <tr>
     <td>Opus</td>
     <td></td>
     <td>REQUIRED<br> (Android 5.0+)</td>
     <td></td>
     <td>Matroska (.mkv)</td>
  </tr>
 </table>


 <p class="table_footnote"> 1 Required for device implementations that define android.hardware.microphone
 but optional for Android Watch device implementations.</p>

 <p class="table_footnote">2 Only downmix of 5.0/5.1 content is required; recording or rendering more than
 2 channels is optional.</p>

 <p class="table_footnote">3 Required for Android Handheld device implementations. </p>

 <p class="table_footnote">4 Required for device implementations that define android.hardware.microphone,
 including Android Watch device implementations.</p>

 <h3 id="5_1_2_image_codecs">5.1.2. Image Codecs</h3>

 <table>
  <tr>
     <th>Format/Codec</th>
     <th>Encoder</th>
     <th>Decoder</th>
     <th>Details</th>
     <th>Supported File Types/Container Formats</th>
  </tr>
  <tr>
     <td>JPEG</td>
     <td>REQUIRED</td>
     <td>REQUIRED</td>
     <td>Base+progressive</td>
     <td>JPEG (.jpg)</td>
  </tr>
  <tr>
     <td>GIF</td>
     <td></td>
     <td>REQUIRED</td>
     <td></td>
     <td>GIF (.gif)</td>
  </tr>
  <tr>
     <td>PNG</td>
     <td>REQUIRED</td>
     <td>REQUIRED</td>
     <td></td>
     <td>PNG (.png)</td>
  </tr>
  <tr>
     <td>BMP</td>
     <td></td>
     <td>REQUIRED</td>
     <td></td>
     <td>BMP (.bmp)</td>
  </tr>
  <tr>
     <td>WebP</td>
     <td>REQUIRED</td>
     <td>REQUIRED</td>
     <td></td>
     <td>WebP (.webp)</td>
  </tr>
 </table>


 <h3 id="5_1_3_video_codecs">5.1.3. Video Codecs</h3>

 <p>Video codecs are optional for Android Watch device implementations.</p>

 <table>
  <tr>
     <th>Format/Codec</th>
     <th>Encoder</th>
     <th>Decoder</th>
     <th>Details</th>
     <th>Supported File Types/<br>Container Formats</th>
  </tr>
  <tr>
     <td>H.263</td>
     <td>REQUIRED<sup>1</sup></td>
     <td>REQUIRED<sup>2</sup></td>
     <td></td>
     <td><ul>
     <li class="table_list">3GPP (.3gp)</li>
     <li class="table_list">MPEG-4 (.mp4)</li></ul></td>
  </tr>
  <tr>
     <td>H.264 AVC</td>
     <td>REQUIRED<sup>2</sup></td>
     <td>REQUIRED<sup>2</sup></td>
     <td>See <a href="#5_2_video_encoding">section 5.2 </a>and <a href="#5_3_video_decoding">5.3</a> for details</td>
     <td><ul>
     <li class="table_list">3GPP (.3gp)</li>
     <li class="table_list">MPEG-4 (.mp4)</li>
     <li class="table_list">MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)</li></ul></td>
  </tr>
  <tr>
     <td>H.265 HEVC</td>
     <td></td>
     <td>REQUIRED<sup>5</sup></td>
     <td>See <a href="#5_3_video_decoding">section 5.3</a> for details</td>
     <td>MPEG-4 (.mp4)</td>
  </tr>
  <tr>
     <td>MPEG-4 SP</td>
     <td></td>
     <td>REQUIRED<sup>2</sup></td>
     <td></td>
     <td>3GPP (.3gp)</td>
  </tr>
  <tr>
     <td>VP8<sup>3</sup></td>
     <td>REQUIRED<sup>2</sup></p>

 <p>(Android 4.3+)</td>
     <td>REQUIRED<sup>2</sup></p>

 <p>(Android 2.3.3+)</td>
     <td>See <a href="#5_2_video_encoding">section 5.2</a> and <a href="#5_3_video_decoding">5.3</a> for details</td>
     <td><ul>
     <li class="table_list">WebM (.webm) [<a href="http://www.webmproject.org/">Resources, 110</a></li>
     <li class="table_list">Matroska (.mkv, Android 4.0+)<sup>4</sup></li></ul></td>
  </tr>
  <tr>
     <td>VP9</td>
     <td></td>
     <td>REQUIRED<sup>2</sup><br> (Android 4.4+)</td>
     <td>See <a href="#5_3_video_decoding">section 5.3</a> for details</td>
     <td><ul>
     <li class="table_list">WebM (.webm) [<a href="http://www.webmproject.org/">Resources, 110</a>]</li>
     <li class="table_list">Matroska (.mkv, Android 4.0+)<sup>4</sup></li></ul></td>
  </tr>
 </table>


 <p class="table_footnote">1 Required for device implementations that include camera hardware and define
 android.hardware.camera or android.hardware.camera.front.</p>

 <p class="table_footnote">2 Required for device implementations except Android Watch devices. </p>

 <p class="table_footnote">3 For acceptable quality of web video streaming and video-conference services,
 device implementations SHOULD use a hardware VP8 codec that meets the
 requirements in [<a href="http://www.webmproject.org/hardware/rtc-coding-requirements/">Resources, 51</a>].</p>

 <p class="table_footnote">4 Device implementations SHOULD support writing Matroska WebM files.</p>

 <p class="table_footnote">5 Strongly recommended for Android Automotive, optional for Android Watch, and required for all other device types.</p>

 <h2 id="5_2_video_encoding">5.2. Video Encoding</h2>

 <div class="note">
 <p>Video codecs are optional for Android Watch device implementations.</p>
 </div>


 <p>Android device implementations with H.264 codec support, MUST support Baseline
 Profile Level 3 and the following SD (Standard Definition) video encoding
 profiles and SHOULD support Main Profile Level 4 and the following HD (High
 Definition) video encoding profiles. Android Television devices are STRONGLY
 RECOMMENDED to encode HD 1080p video at 30 fps.</p>
 <table>
  <tr>
     <th></th>
     <th>SD (Low quality)</th>
     <th>SD (High quality)</th>
     <th>HD 720p1</th>
     <th>HD 1080p1</th>
  </tr>
  <tr>
     <th>Video resolution</th>
     <td>320 x 240 px</td>
     <td>720 x 480 px</td>
     <td>1280 x 720 px</td>
     <td>1920 x 1080 px</td>
  </tr>
  <tr>
     <th>Video frame rate</th>
     <td>20 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
  </tr>
  <tr>
     <th>Video bitrate</th>
     <td>384 Kbps</td>
     <td>2 Mbps</td>
     <td>4 Mbps</td>
     <td>10 Mbps</td>
  </tr>
 </table>


 <p class="table_footnote">1 When supported by hardware, but STRONGLY RECOMMENDED for Android Television
 devices.</p>

 <p>Android device implementations with VP8 codec support MUST support the SD video
 encoding profiles and SHOULD support the following HD (High Definition) video
 encoding profiles.</p>
 <table>
  <tr>
     <th></th>
     <th>SD (Low quality)</th>
     <th>SD (High quality)</th>
     <th>HD 720p1</th>
     <th>HD 1080p1</th>
  </tr>
  <tr>
     <th>Video resolution</th>
     <td>320 x 180 px</td>
     <td>640 x 360 px</td>
     <td>1280 x 720 px</td>
     <td>1920 x 1080 px</td>
  </tr>
  <tr>
     <th>Video frame rate</th>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
  </tr>
  <tr>
     <th>Video bitrate</th>
     <td>800 Kbps </td>
     <td>2 Mbps</td>
     <td>4 Mbps</td>
     <td>10 Mbps</td>
  </tr>
 </table>

 <p class="table_footnote">1 When supported by hardware.</p>

 <h2 id="5_3_video_decoding">5.3. Video Decoding</h2>

 <div class="note">
 <p>Video codecs are optional for Android Watch device implementations.</p>
 </div>


 <p>Device implementations MUST support dynamic video resolution switching within
 the same stream for all VP8, VP9, H.264, and H.265 codecs exposed through the
 standard Android APIs.</p>

 <p>Android device implementations with H.264 decoders, MUST support Baseline
 Profile Level 3 and the following SD video decoding profiles and SHOULD support
 the HD decoding profiles. Android Television devices MUST support High Profile
 Level 4.2 and the HD 1080p decoding profile.</p>
 <table>
  <tr>
     <th></th>
     <th>SD (Low quality)</th>
     <th>SD (High quality)</th>
     <th>HD 720p1</th>
     <th>HD 1080p1</th>
  </tr>
  <tr>
     <th>Video resolution</th>
     <td>320 x 240 px</td>
     <td>720 x 480 px</td>
     <td>1280 x 720 px</td>
     <td>1920 x 1080 px</td>
  </tr>
  <tr>
     <th>Video frame rate</th>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps / 60 fps2</td>
     <td>30 fps / 60 fps2</td>
  </tr>
  <tr>
     <th>Video bitrate</th>
     <td>800 Kbps </td>
     <td>2 Mbps</td>
     <td>8 Mbps</td>
     <td>20 Mbps</td>
  </tr>
 </table>


 <p class="table_footnote">1 Required for Android Television device implementations, but for other device
 types only when supported by hardware.</p>

 <p class="table_footnote">2 Required for Android Television device implementations.</p>

 <p>Android device implementations when supporting VP8 codec as described in <a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the following SD decoding profiles and SHOULD support the HD
 decoding profiles. Android Television devices MUST support the HD 1080p
 decoding profile.  </p>
 <table>
  <tr>
     <th></th>
     <th>SD (Low quality)</th>
     <th>SD (High quality)</th>
     <th>HD 720p1</th>
     <th>HD 1080p1</th>
  </tr>
  <tr>
     <th>Video resolution</th>
     <td>320 x 180 px</td>
     <td>640 x 360 px</td>
     <td>1280 x 720 px</td>
     <td>1920 x 1080 px</td>
  </tr>
  <tr>
     <th>Video frame rate</th>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps / 60 fps2</td>
     <td>30 / 60 fps2</td>
  </tr>
  <tr>
     <th>Video bitrate</th>
     <td>800 Kbps </td>
     <td>2 Mbps</td>
     <td>8 Mbps</td>
     <td>20 Mbps</td>
  </tr>
 </table>


 <p class="table_footnote">1 Required for Android Television device implementations, but for other type of
 devices only when supported by hardware.</p>

 <p class="table_footnote">2 Required for Android Television device implementations.</p>

 <p>Android device implementations, when supporting VP9 codec as described in <a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the following SD video decoding profiles and SHOULD support the
 HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to
 support the HD 1080p decoding profile and SHOULD support the UHD decoding
 profile. When the UHD video decoding profile is supported, it MUST support 8
 bit color depth.</p>
 <table>
  <tr>
     <th></th>
     <th>SD (Low quality)</th>
     <th>SD (High quality)</th>
     <th>HD 720p 1</th>
     <th>HD 1080p 2</th>
     <th>UHD 2</th>
  </tr>
  <tr>
     <th>Video resolution</th>
     <td>320 x 180 px</td>
     <td>640 x 360 px</td>
     <td>1280 x 720 px</td>
     <td>1920 x 1080 px</td>
     <td>3840 x 2160 px</td>
  </tr>
  <tr>
     <th>Video frame rate</th>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
  </tr>
  <tr>
     <th>Video bitrate</th>
     <td>600 Kbps </td>
     <td>1.6 Mbps</td>
     <td>4 Mbps</td>
     <td>10 Mbps</td>
     <td>20 Mbps</td>
  </tr>
 </table>


 <p class="table_footnote">1 Required for Android Television device implementations, but for other type of
 devices only when supported by hardware.</p>

 <p class="table_footnote">2 STRONGLY RECOMMENDED for Android Television device implementations when
 supported by hardware.</p>

 <p>Android device implementations, when supporting H.265 codec as described in <a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the Main Profile Level 3 Main tier and the following SD video
 decoding profiles and SHOULD support the HD decoding profiles. Android
 Television devices MUST support the Main Profile Level 4.1 Main tier and the HD
 1080p decoding profile and SHOULD support Main10 Level 5 Main Tier profile and
 the UHD decoding profile.</p>
 <table>
  <tr>
     <th></th>
     <th>SD (Low quality)</th>
     <th>SD (High quality)</th>
     <th>HD 720p </strong>1 </td>
     <th>HD 1080p </strong>1 </td>
     <th>UHD </strong>2</td>
  </tr>
  <tr>
     <th>Video resolution</th>
     <td>352 x 288 px</td>
     <td>640 x 360 px</td>
     <td>1280 x 720 px</td>
     <td>1920 x 1080 px</td>
     <td>3840 x 2160 px</td>
  </tr>
  <tr>
     <th>Video frame rate</th>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
     <td>30 fps</td>
  </tr>
  <tr>
     <th>Video bitrate</th>
     <td>600 Kbps </td>
     <td>1.6 Mbps</td>
     <td>4 Mbps</td>
     <td>10 Mbps</td>
     <td>20 Mbps</td>
  </tr>
 </table>


 <p class="table_footnote">1 Required for Android Television device implementation, but for other type of
 devices only when supported by hardware.</p>

 <p class="table_footnote">2 Required for Android Television device implementations when supported by
 hardware.</p>

 <h2 id="5_4_audio_recording">5.4. Audio Recording</h2>


 <p>While some of the requirements outlined in this section are stated as SHOULD
 since Android 4.3, the Compatibility Definition for a future version is planned
 to change these to MUST. Existing and new Android devices are <strong>very strongly encouraged</strong> to meet these requirements, or they will not be able to attain Android
 compatibility when upgraded to the future version.</p>

 <h3 id="5_4_1_raw_audio_capture">5.4.1. Raw Audio Capture</h3>


 <p>Device implementations that declare android.hardware.microphone MUST allow
 capture of raw audio content with the following characteristics:</p>

 <ul>
   <li><strong>Format</strong>: Linear PCM, 16-bit
   <li><strong>Sampling rates</strong>: 8000, 11025, 16000, 44100
   <li><strong>Channels</strong>: Mono
 </ul>

 <p>Device implementations that declare android.hardware.microphone SHOULD allow
 capture of raw audio content with the following characteristics:</p>

 <ul>
   <li><strong>Format</strong>: Linear PCM, 16-bit
   <li><strong>Sampling rates</strong>: 22050, 48000
   <li><strong>Channels</strong>: Stereo
 </ul>

 <h3 id="5_4_2_capture_for_voice_recognition">5.4.2. Capture for Voice Recognition</h3>


 <p>In addition to the above recording specifications, when an application has
 started recording an audio stream using the
 android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:</p>

 <ul>
   <li>The device SHOULD exhibit approximately flat amplitude versus frequency
 characteristics: specifically, ±3 dB, from 100 Hz to 4000 Hz.
   <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level (SPL)
 source at 1000 Hz yields RMS of 2500 for 16-bit samples.
   <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least a 30
 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.
   <li>Total harmonic distortion SHOULD be less than 1% for 1Khz at 90 dB SPL input
 level at the microphone.
   <li>Noise reduction processing, if present, MUST be disabled.
   <li>Automatic gain control, if present, MUST be disabled
 </ul>

 <p>If the platform supports noise suppression technologies tuned for speech
 recognition, the effect MUST be controllable from the
 android.media.audiofx.NoiseSuppressor API. Moreover, the UUID field for the
 noise suppressor&rsquo;s effect descriptor MUST uniquely identify each implementation
 of the noise suppression technology.</p>

 <h3 id="5_4_3_capture_for_rerouting_of_playback">5.4.3. Capture for Rerouting of Playback</h3>


 <p>The android.media.MediaRecorder.AudioSource class includes the REMOTE_SUBMIX
 audio source. Devices that declare android.hardware.audio.output MUST properly
 implement the REMOTE_SUBMIX audio source so that when an application uses the
 android.media.AudioRecord API to record from this audio source, it can capture
 a mix of all audio streams except for the following:</p>

 <ul>
   <li>STREAM_RING
   <li>STREAM_ALARM
   <li>STREAM_NOTIFICATION
 </ul>

 <h2 id="5_5_audio_playback">5.5. Audio Playback</h2>


 <p>Device implementations that declare android.hardware.audio.output MUST conform
 to the requirements in this section.</p>

 <h3 id="5_5_1_raw_audio_playback">5.5.1. Raw Audio Playback</h3>


 <p>The device MUST allow playback of raw audio content with the following
 characteristics:</p>

 <ul>
   <li><strong>Format</strong>: Linear PCM, 16-bit</li>
   <li><strong>Sampling rates</strong>: 8000, 11025, 16000, 22050, 32000, 44100</li>
   <li><strong>Channels</strong>: Mono, Stereo</li>
 </ul>

 <p>The device SHOULD allow playback of raw audio content with the following
 characteristics:</p>

 <ul>
   <li><strong>Sampling rates</strong>: 24000, 48000</li>
 </ul>

 <h3 id="5_5_2_audio_effects">5.5.2. Audio Effects</h3>


 <p>Android provides an API for audio effects for device implementations [<a href="http://developer.android.com/reference/android/media/audiofx/AudioEffect.html">Resources, 52</a>]. Device implementations that declare the feature
 android.hardware.audio.output:</p>

 <ul>
   <li>MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER
 implementations controllable through the AudioEffect subclasses Equalizer,
 LoudnessEnhancer.</li>
   <li>MUST support the visualizer API implementation, controllable through the
 Visualizer class.</li>
   <li>SHOULD support the EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_ENV_REVERB,
 EFFECT_TYPE_PRESET_REVERB, and EFFECT_TYPE_VIRTUALIZER implementations
 controllable through the AudioEffect sub-classes BassBoost,
 EnvironmentalReverb, PresetReverb, and Virtualizer.</li>
 </ul>

 <h3 id="5_5_3_audio_output_volume">5.5.3. Audio Output Volume</h3>


 <p>Android Television device implementations MUST include support for system
 Master Volume and digital audio output volume attenuation on supported outputs,
 except for compressed audio passthrough output (where no audio decoding is done
 on the device).</p>

 <h2 id="5_6_audio_latency">5.6. Audio Latency</h2>


 <p>Audio latency is the time delay as an audio signal passes through a system.
 Many classes of applications rely on short latencies, to achieve real-time
 sound effects.</p>

 <p>For the purposes of this section, use the following definitions:</p>

 <ul>
   <li><strong>output latency</strong>. The interval between when an application writes a frame of PCM-coded data and
 when the corresponding sound can be heard by an external listener or observed
 by a transducer.</li>
   <li><strong>cold output latency</strong>. The output latency for the first frame, when the audio output system has been
 idle and powered down prior to the request.</li>
   <li><strong>continuous output latency</strong>. The output latency for subsequent frames, after the device is playing audio.</li>
   <li><strong>input latency</strong>. The interval between when an external sound is presented to the device and
 when an application reads the corresponding frame of PCM-coded data.</li>
   <li><strong>cold input latency</strong>. The sum of lost input time and the input latency for the first frame, when the
 audio input system has been idle and powered down prior to the request.</li>
   <li><strong>continuous input latency</strong>. The input latency for subsequent frames, while the device is capturing audio.</li>
   <li><strong>cold output jitter</strong>. The variance among separate measurements of cold output latency values.</li>
   <li><strong>cold input jitter</strong>. The variance among separate measurements of cold input latency values.</li>
   <li><strong>continuous round-trip latency</strong>. The sum of continuous input latency plus continuous output latency plus
   one buffer period.
   The buffer period term allows processing time for the app and for the app to
   mitigate phase difference between input and output streams.
   </li>
   <li><strong>OpenSL ES PCM buffer queue API</strong>. The set of PCM-related OpenSL ES APIs within Android NDK; see
 NDK_root/docs/opensles/index.html.</li>
 </ul>

 <p>Device implementations that declare android.hardware.audio.output are STRONGLY ENCOURAGED to meet
 or exceed these audio output requirements:</p>

 <ul>
   <li>cold output latency of 100 milliseconds or less</li>
   <li>continuous output latency of 45 milliseconds or less</li>
   <li>minimize the cold output jitter</li>
 </ul>

 <p>If a device implementation meets the requirements of this section after any
 initial calibration when using the OpenSL ES PCM buffer queue API, for
 continuous output latency and cold output latency over at least one supported
 audio output device, it MAY report support for low-latency audio, by reporting
 the feature android.hardware.audio.low_latency via the
 android.content.pm.PackageManager class [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 53</a>]. Conversely, if the device implementation does not meet these requirements it
 MUST NOT report support for low-latency audio.</p>

 <p>Device implementations that include android.hardware.microphone are STRONGLY ENCOURAGED to meet
 these input audio requirements:</p>

 <ul>
   <li>cold input latency of 100 milliseconds or less</li>
   <li>continuous input latency of 30 milliseconds or less</li>
   <li>continuous round-trip latency of 50 milliseconds or less</li>
   <li>minimize the cold input jitter</li>
 </ul>

 <h2 id="5_7_network_protocols">5.7. Network Protocols</h2>


 <p>Devices MUST support the media network protocols for audio and video playback
 as specified in the Android SDK documentation [<a href="http://developer.android.com/guide/appendix/media-formats.html">Resources, 50</a>]. Specifically, devices MUST support the following media network protocols:</p>

 <ul>
   <li>RTSP (RTP, SDP)</li>
   <li>HTTP(S) progressive streaming</li>
   <li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">Resources, 54</a>]</li>
 </ul>

 <h2 id="5_8_secure_media">5.8. Secure Media</h2>


 <p>Device implementations that support secure video output and are capable of
 supporting secure surfaces MUST declare support for Display.FLAG_SECURE. Device
 implementations that declare support for Display.FLAG_SECURE, if they support a
 wireless display protocol, MUST secure the link with a cryptographically strong
 mechanism such as HDCP 2.x or higher for Miracast wireless displays. Similarly
 if they support a wired external display, the device implementations MUST
 support HDCP 1.2 or higher. Android Television device implementations MUST
 support HDCP 2.2 for devices supporting 4K resolution and HDCP 1.4 or above for
 lower resolutions. The upstream Android open source implementation includes
 support for wireless (Miracast) and wired (HDMI) displays that satisfies this
 requirement.</p>

 <h2 id="5_9_midi">5.9. Musical Instrument Digital Interface (MIDI)</h2>

 <p>
 If a device implementation supports the inter-app MIDI software transport
 (virtual MIDI devices), and it supports MIDI over
 <em>all</em> of the following MIDI-capable hardware transports
 for which it provides generic non-MIDI connectivity, it MAY report
 support for feature android.software.midi via the
 android.content.pm.PackageManager class
 [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 53</a>].
 </p>

 <p>The MIDI-capable hardware transports are:</p>
 <ul>
   <li>USB host mode (section 7.7 USB)</li>
   <li>USB peripheral mode (section 7.7 USB)</li>
 </ul>

 <p>
 Conversely, if the device implementation provides generic non-MIDI connectivity over a particular
 MIDI-capable hardware transport listed above, but does not support MIDI over that hardware transport,
 it MUST NOT report support for feature android.software.midi.
 </p>

 <p>
 MIDI over Bluetooth LE acting in central role (section 7.4.3 Bluetooth)
 is in trial use status.  A device implementation that reports
 feature android.software.midi, and which provides generic non-MIDI connectivity
 over Bluetooth LE, SHOULD support MIDI over Bluetooth LE.
 </p>

 <h2 id="5_10_pro_audio">5.10. Professional Audio</h2>

 <p>
 If a device implementation meets <em>all</em> of the following requirements,
 it MAY report support for feature android.hardware.audio.pro via the
 android.content.pm.PackageManager class
 [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 53</a>].
 </p>

 <ul>

 <li>
 The device implementation MUST report support for feature android.hardware.audio.low_latency.
 </li>

 <li> The continuous round-trip audio latency, as defined in section 5.6 Audio Latency,
 MUST be 20 milliseconds or less and SHOULD be 10 milliseconds or less over at least one
 supported path.
 </li>

 <li>
 If the device includes a 4 conductor 3.5mm audio jack,
 the continuous round-trip audio latency MUST be 20 milliseconds or less over the audio jack path,
 and SHOULD be 10 milliseconds or less over at the audio jack path.
 </li>

 <li>
 The device implementation MUST include a USB port(s) supporting USB host mode and
 USB peripheral mode.
 </li>

 <li>
 The USB host mode MUST implement the USB audio class.
 </li>

 <li>
 If the device includes an HDMI port, the device implementation
 MUST support output in stereo and eight channels
 at 20-bit or 24-bit depth and 192 kHz without bit-depth loss or resampling.
 </li>

 <li>
 The device implementation MUST report support for feature android.software.midi.
 </li>

 <li>
 If the device includes a 4 conductor 3.5mm audio jack,
 the device implementation is STRONGLY ENCOURAGED to comply with section
 <a href="https://source.android.com/accessories/headset/specification.html#mobile_device_jack_specifications">Mobile device (jack) specifications</a>
 of the
 <a href="https://source.android.com/accessories/headset/specification.html">Wired Audio Headset Specification (v1.1)</a>.
 </li>

 </ul>

 <h1 id="6_developer_tools_and_options_compatibility">6. Developer Tools and Options Compatibility</h1>

 <h2 id="6_1_developer_tools">6.1. Developer Tools</h2>

 <p>Device implementations MUST support the Android Developer Tools provided in the
 Android SDK. Android compatible devices MUST be compatible with:</p>

 <ul>
   <li><strong>Android Debug Bridge (adb)</strong> [<a href="http://developer.android.com/tools/help/adb.html">Resources, 55</a>]</li>
 </ul>

 <p>Device implementations MUST support all adb functions as documented in the
 Android SDK including dumpsys [<a href="https://source.android.com/devices/input/diagnostics.html">Resources, 56</a>]. The device-side adb daemon MUST be inactive by default and there MUST be a
 user-accessible mechanism to turn on the Android Debug Bridge. If a device
 implementation omits USB peripheral mode, it MUST implement the Android Debug
 Bridge via local-area network (such as Ethernet or 802.11). </p>

 <p>Android includes support for secure adb. Secure adb enables adb on known
 authenticated hosts. Device implementations MUST support secure adb.</p>

 <ul>
   <li><strong>Dalvik Debug Monitor Service (ddms)</strong> [<a href="http://developer.android.com/tools/debugging/ddms.html">Resources, 57</a>]</li>
 </ul>

 <p>Device implementations MUST support all ddms features as documented in the
 Android SDK. As ddms uses adb, support for ddms SHOULD be inactive by default,
 but MUST be supported whenever the user has activated the Android Debug Bridge,
 as above.</p>

 <ul>
   <li><strong>Monkey</strong> [<a href="http://developer.android.com/tools/help/monkey.html">Resources, 58</a>]</li>
 </ul>

 <p>Device implementations MUST include the Monkey framework, and make it available
 for applications to use.</p>

 <ul>
   <li><strong>SysTrace</strong> [<a href="http://developer.android.com/tools/help/systrace.html">Resources, 59</a>]</li>
 </ul>

 <p>Device implementations MUST support systrace tool as documented in the Android
 SDK. Systrace must be inactive by default, and there MUST be a user-accessible
 mechanism to turn on Systrace.</p>

 <p>Most Linux-based systems and Apple Macintosh systems recognize Android devices
 using the standard Android SDK tools, without additional support; however
 Microsoft Windows systems typically require a driver for new Android devices.
 (For instance, new vendor IDs and sometimes new device IDs require custom USB
 drivers for Windows systems.) If a device implementation is unrecognized by the
 adb tool as provided in the standard Android SDK, device implementers MUST
 provide Windows drivers allowing developers to connect to the device using the
 adb protocol. These drivers MUST be provided for Windows XP, Windows Vista,
 Windows 7, Windows 8, and Windows 9 in both 32-bit and 64-bit versions.</p>

 <h2 id="6_2_developer_options">6.2. Developer Options</h2>


 <p>Android includes support for developers to configure application
 development-related settings. Device implementations MUST honor the
 android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show application
 development-related settings [<a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">Resources, 60</a>]. The upstream Android implementation hides the Developer Options menu by
 default and enables users to launch Developer Options after pressing seven (7)
 times on the <strong>Settings</strong> > <strong>About Device</strong> > <strong>Build Number</strong> menu item. Device implementations MUST provide a consistent experience for
 Developer Options. Specifically, device implementations MUST hide Developer
 Options by default and MUST provide a mechanism to enable Developer Options
 that is consistent with the upstream Android implementation.</p>

 <h1 id="7_hardware_compatibility">7. Hardware Compatibility</h1>


 <p>If a device includes a particular hardware component that has a corresponding
 API for third-party developers, the device implementation MUST implement that
 API as described in the Android SDK documentation. If an API in the SDK
 interacts with a hardware component that is stated to be optional and the
 device implementation does not possess that component:</p>

 <ul>
   <li>Complete class definitions (as documented by the SDK) for the component APIs
 MUST still be presented.
   <li>The API&rsquo;s behaviors MUST be implemented as no-ops in some reasonable fashion.
   <li>API methods MUST return null values where permitted by the SDK documentation.
   <li>API methods MUST return no-op implementations of classes where null values are
 not permitted by the SDK documentation.
   <li>API methods MUST NOT throw exceptions not documented by the SDK documentation.
 </ul>

 <p>A typical example of a scenario where these requirements apply is the telephony
 API: even on non-phone devices, these APIs must be implemented as reasonable
 no-ops.</p>

 <p>Device implementations MUST consistently report accurate hardware configuration
 information via the getSystemAvailableFeatures() and hasSystemFeature(String)
 methods on the android.content.pm.PackageManager class for the same build
 fingerprint. [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 53]</a></p>

 <h2 id="7_1_display_and_graphics">7.1. Display and Graphics</h2>


 <p>Android includes facilities that automatically adjust application assets and UI
 layouts appropriately for the device, to ensure that third-party applications
 run well on a variety of hardware configurations [<a href="http://developer.android.com/guide/practices/screens_support.html">Resources, 61</a>]. Devices MUST properly implement these APIs and behaviors, as detailed in
 this section.</p>

 <p>The units referenced by the requirements in this section are defined as
 follows:</p>

 <ul>
   <li><strong>physical diagonal size</strong>. The distance in inches between two opposing corners of the illuminated portion
 of the display.</li>
   <li><strong>dots per inch (dpi)</strong>. The number of pixels encompassed by a linear horizontal or vertical span of
 1&rdquo;. Where dpi values are listed, both horizontal and vertical dpi must fall
 within the range.</li>
   <li><strong>aspect ratio</strong>. The ratio of the pixels of the longer dimension
   to the shorter dimension of the screen. For example, a display of 480x854 pixels
   would be 854/480 = 1.779, or roughly &ldquo;16:9&rdquo;.</li>
   <li><strong>density-independent pixel (dp)</strong> The virtual pixel unit normalized to a 160 dpi screen, calculated as: pixels =
 dps * (density/160).</li>
 </ul>

 <h3 id="7_1_1_screen_configuration">7.1.1. Screen Configuration</h3>


 <h4 id="7_1_1_1_screen_size">7.1.1.1. Screen Size</h4>

 <div class="note">
 <p>Android Watch devices (detailed in <a href="#2_device_types">section 2</a>) MAY have smaller screen sizes as described in this section.</p>
 </div>

 <p>The Android UI framework supports a variety of different screen sizes, and
 allows applications to query the device screen size (aka &ldquo;screen layout") via
 android.content.res.Configuration.screenLayout with the SCREENLAYOUT_SIZE_MASK.
 Device implementations MUST report the correct screen size as defined in the
 Android SDK documentation [<a href="http://developer.android.com/guide/practices/screens_support.html">Resources, 61</a>] and determined by the upstream Android platform. Specifically, device
 implementations MUST report the correct screen size according to the following
 logical density-independent pixel (dp) screen dimensions.</p>

 <ul>
   <li>Devices MUST have screen sizes of at least 426 dp x 320 dp (&lsquo;small&rsquo;), unless it
 is an Android Watch device.</li>
   <li>Devices that report screen size &lsquo;normal&rsquo; MUST have screen sizes of at least 480
 dp x 320 dp.</li>
   <li>Devices that report screen size &lsquo;large&rsquo; MUST have screen sizes of at least 640
 dp x 480 dp.</li>
   <li>Devices that report screen size &lsquo;xlarge&rsquo; MUST have screen sizes of at least 960
 dp x 720 dp.</li>
 </ul>

 <p>In addition, </p>

 <ul>
   <li>Android Watch devices MUST have a screen with the physical diagonal size in the
 range from 1.1 to 2.5 inches.</li>
   <li>Other types of Android device implementations, with a physically integrated
 screen, MUST have a screen at least 2.5 inches in physical diagonal size.</li>
 </ul>

 <p>Devices MUST NOT change their reported screen size at any time.</p>

 <p>Applications optionally indicate which screen sizes they support via the
 &lt;supports-screens&gt; attribute in the AndroidManifest.xml file. Device
 implementations MUST correctly honor applications' stated support for small,
 normal, large, and xlarge screens, as described in the Android SDK
 documentation.</p>

 <h4 id="7_1_1_2_screen_aspect_ratio">7.1.1.2. Screen Aspect Ratio</h4>

 <div class="note">
 <p>Android Watch devices MAY have an aspect ratio of 1.0 (1:1).</p>
 </div>


 <p>The screen aspect ratio MUST be a value from 1.3333 (4:3) to 1.86 (roughly
 16:9), but Android Watch devices MAY have an aspect ratio of 1.0 (1:1) because
 such a device implementation will use a UI_MODE_TYPE_WATCH as the
 android.content.res.Configuration.uiMode.</p>

 <h4 id="7_1_1_3_screen_density">7.1.1.3. Screen Density</h4>


 <p>The Android UI framework defines a set of standard logical densities to help
 application developers target application resources. Device implementations
 MUST report only one of the following logical Android framework densities
 through the android.util.DisplayMetrics APIs, and MUST execute applications at
 this standard density and MUST NOT change the value at at any time for the
 default display.</p>

 <ul>
   <li>120 dpi (ldpi)</li>
   <li>160 dpi (mdpi)</li>
   <li>213 dpi (tvdpi)</li>
   <li>240 dpi (hdpi)</li>
   <li>280 dpi (280dpi)</li>
   <li>320 dpi (xhdpi)</li>
   <li>400 dpi (400dpi)</li>
   <li>480 dpi (xxhdpi)</li>
   <li>560 dpi (560dpi)</li>
   <li>640 dpi (xxxhdpi)</li>
 </ul>

 <p>Device implementations SHOULD define the standard Android framework density
 that is numerically closest to the physical density of the screen, unless that
 logical density pushes the reported screen size below the minimum supported. If
 the standard Android framework density that is numerically closest to the
 physical density results in a screen size that is smaller than the smallest
 supported compatible screen size (320 dp width), device implementations SHOULD
 report the next lowest standard Android framework density.</p>

 <h3 id="7_1_2_display_metrics">7.1.2. Display Metrics</h3>


 <p>Device implementations MUST report correct values for all display metrics
 defined in android.util.DisplayMetrics [<a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">Resources, 62</a>] and MUST report the same values regardless of whether the embedded or
 external screen is used as the default display.</p>

 <h3 id="7_1_3_screen_orientation">7.1.3. Screen Orientation</h3>


 <p>Devices MUST report which screen orientations they support
 (android.hardware.screen.portrait and/or android.hardware.screen.landscape) and
 MUST report at least one supported orientation. For example, a device with a
 fixed orientation landscape screen, such as a television or laptop, SHOULD only
 report android.hardware.screen.landscape.</p>

 <p>Devices that report both screen orientations MUST support dynamic orientation
 by applications to either portrait or landscape screen orientation. That is,
 the device must respect the application&rsquo;s request for a specific screen
 orientation. Device implementations MAY select either portrait or landscape
 orientation as the default.</p>

 <p>Devices MUST report the correct value for the device&rsquo;s current orientation,
 whenever queried via the android.content.res.Configuration.orientation,
 android.view.Display.getOrientation(), or other APIs.</p>

 <p>Devices MUST NOT change the reported screen size or density when changing
 orientation.</p>

 <h3 id="7_1_4_2d_and_3d_graphics_acceleration">7.1.4. 2D and 3D Graphics Acceleration</h3>


 <p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied and
 detailed in the Android SDK documentations. Device implementations SHOULD
 support OpenGL ES 3.0 or 3.1 on devices capable of supporting it. Device
 implementations MUST also support Android RenderScript, as detailed in the
 Android SDK documentation [<a href="http://developer.android.com/guide/topics/renderscript/">Resources, 63</a>].</p>

 <p>Device implementations MUST also correctly identify themselves as supporting
 OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0 or OpenGL 3.1. That is:</p>

 <ul>
   <li>The managed APIs (such as via the GLES10.getString() method) MUST report support
 for OpenGL ES 1.0 and OpenGL ES 2.0.</li>
   <li>The native C/C++ OpenGL APIs (APIs available to apps via libGLES_v1CM.so,
 libGLES_v2.so, or libEGL.so) MUST report support for OpenGL ES 1.0 and OpenGL
 ES 2.0.</li>
   <li>Device implementations that declare support for OpenGL ES 3.0 or 3.1 MUST
 support the corresponding managed APIs and include support for native C/C++
 APIs. On device implementations that declare support for OpenGL ES 3.0 or 3.1,
 libGLESv2.so MUST export the corresponding function symbols in addition to the
 OpenGL ES 2.0 function symbols.</li>
 </ul>

 <p>In addition to OpenGL ES 3.1, Android provides an extension pack with Java
 interfaces [<a href="https://developer.android.com/reference/android/opengl/GLES31Ext.html">Resources, 64</a>] and native support for advanced graphics functionality such as tessellation
 and the ASTC texture compression format. Android device implementations MAY
 support this extension pack, and&mdash;only if fully implemented&mdash;MUST identify the
 support through the android.hardware.opengles.aep feature flag.</p>

 <p>Also, device implementations MAY implement any desired OpenGL ES extensions.
 However, device implementations MUST report via the OpenGL ES managed and
 native APIs all extension strings that they do support, and conversely MUST NOT
 report extension strings that they do not support.</p>

 <p>Note that Android includes support for applications to optionally specify that
 they require specific OpenGL texture compression formats. These formats are
 typically vendor-specific. Device implementations are not required by Android
 to implement any specific texture compression format. However, they SHOULD
 accurately report any texture compression formats that they do support, via the
 getString() method in the OpenGL API.</p>

 <p>Android includes a mechanism for applications to declare that they want to
 enable hardware acceleration for 2D graphics at the Application, Activity,
 Window, or View level through the use of a manifest tag
 android:hardwareAccelerated or direct API calls [<a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">Resources, 65</a>].</p>

 <p>Device implementations MUST enable hardware acceleration by default, and MUST
 disable hardware acceleration if the developer so requests by setting
 android:hardwareAccelerated="false&rdquo; or disabling hardware acceleration directly
 through the Android View APIs.</p>

 <p>In addition, device implementations MUST exhibit behavior consistent with the
 Android SDK documentation on hardware acceleration [<a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">Resources, 65</a>].</p>

 <p>Android includes a TextureView object that lets developers directly integrate
 hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy.
 Device implementations MUST support the TextureView API, and MUST exhibit
 consistent behavior with the upstream Android implementation.</p>

 <p>Android includes support for EGL_ANDROID_RECORDABLE, an EGLConfig attribute
 that indicates whether the EGLConfig supports rendering to an ANativeWindow
 that records images to a video. Device implementations MUST support
 EGL_ANDROID_RECORDABLE extension [<a href="https://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt">Resources, 66</a>].</p>

 <h3 id="7_1_5_legacy_application_compatibility_mode">7.1.5. Legacy Application Compatibility Mode</h3>


 <p>Android specifies a &ldquo;compatibility mode&rdquo; in which the framework operates in a
 'normal' screen size equivalent (320dp width) mode for the benefit of legacy
 applications not developed for old versions of Android that pre-date
 screen-size independence.</p>

 <ul>
 <li>Android Automotive does not support legacy compatibility mode.</li>
 <li>All other device implementations MUST include support for legacy application
 compatibility mode as implemented by the upstream Android open source code. That
 is, device implementations MUST NOT alter the triggers or thresholds at which
 compatibility mode is activated, and MUST NOT alter the behavior of the
 compatibility mode itself.</li>
 </ul>

 <h3 id="7_1_6_screen_technology">7.1.6. Screen Technology</h3>


 <p>The Android platform includes APIs that allow applications to render rich
 graphics to the display. Devices MUST support all of these APIs as defined by
 the Android SDK unless specifically allowed in this document. </p>

 <ul>
   <li>Devices MUST support displays capable of rendering 16-bit color graphics and
 SHOULD support displays capable of 24-bit color graphics.</li>
   <li>Devices MUST support displays capable of rendering animations.</li>
   <li>The display technology used MUST have a pixel aspect ratio (PAR) between 0.9
 and 1.15. That is, the pixel aspect ratio MUST be near square (1.0) with a 10 ~
 15% tolerance.</li>
 </ul>

 <h3 id="7_1_7_external_displays">7.1.7. Secondary Displays</h3>


 <p>Android includes support for secondary display to enable media sharing
 capabilities and developer APIs for accessing external displays. If a device
 supports an external display either via a wired, wireless, or an embedded
 additional display connection then the device implementation MUST implement the
 display manager API as described in the Android SDK documentation [<a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">Resources, 67</a>].</p>

 <h2 id="7_2_input_devices">7.2. Input Devices</h2>

 <p>Devices MUST support a touchscreen or meet the requirements listed in 7.2.2
 for non-touch navigation.</p>

 <h3 id="7_2_1_keyboard">7.2.1. Keyboard</h3>

 <div class="note">
 <p>Android Watch and Android Automotive implementations MAY implement a soft
 keyboard. All other device implementations MUST implement a soft keyboard and:</p>
 </div>


 <p>Device implementations:</p>

 <ul>
   <li>MUST include support for the Input Management Framework (which allows
 third-party developers to create Input Method Editors&mdash;i.e. soft keyboard) as
 detailed at <a href="http://developer.android.com">http://developer.android.com</a>.</li>
   <li>MUST provide at least one soft keyboard implementation (regardless of whether a
 hard keyboard is present) except for Android Watch devices where the screen
 size makes it less reasonable to have a soft keyboard.</li>
   <li>MAY include additional soft keyboard implementations.</li>
   <li>MAY include a hardware keyboard.</li>
   <li>MUST NOT include a hardware keyboard that does not match one of the formats
 specified in android.content.res.Configuration.keyboard [<a href="http://developer.android.com/reference/android/content/res/Configuration.html">Resources, 68</a>] (QWERTY or 12-key).</li>
 </ul>

 <h3 id="7_2_2_non-touch_navigation">7.2.2. Non-touch Navigation</h3>

 <div class="note">
 <p>Android Television devices MUST support D-pad.</p>
 </div>

 <p>Device implementations:</p>

 <ul>
   <li>MAY omit a non-touch navigation option (trackball, d-pad, or wheel) if the
 device implementation is not an Android Television device.</li>
   <li>MUST report the correct value for android.content.res.Configuration.navigation
 [<a href="http://developer.android.com/reference/android/content/res/Configuration.html">Resources, 68</a>].</li>
   <li>MUST provide a reasonable alternative user interface mechanism for the
 selection and editing of text, compatible with Input Management Engines. The
 upstream Android open source implementation includes a selection mechanism
 suitable for use with devices that lack non-touch navigation inputs.</li>
 </ul>

 <h3 id="7_2_3_navigation_keys">7.2.3. Navigation Keys</h3>

 <div class="note">
 <p>The availability and visibility requirement of the Home, Recents, and Back
 functions differ between device types as described in this section.</p>
 </div>

 <p>The Home, Recents, and Back functions (mapped to the key events KEYCODE_HOME,
 KEYCODE_APP_SWITCH, KEYCODE_BACK, respectively) are essential to the Android
 navigation paradigm and therefore:</p>

 <ul>
   <li>Android Handheld device implementations MUST provide the Home, Recents, and
 Back functions.</li>
   <li>Android Television device implementations MUST provide the Home and Back
 functions.</li>
   <li>Android Watch device implementations MUST have the Home function available to
 the user, and the Back function except for when it is in UI_MODE_TYPE_WATCH.</li>
   <li>Android Automotive implementations MUST provide the Home function and MAY
 provide Back and Recent functions.</li>
   <li>All other types of device implementations MUST provide the Home and Back
 functions.</li>
 </ul>

 <p>These functions MAY be implemented via dedicated physical buttons (such as
 mechanical or capacitive touch buttons), or MAY be implemented using dedicated
 software keys on a distinct portion of the screen, gestures, touch panel, etc.
 Android supports both implementations. All of these functions MUST be
 accessible with a single action (e.g. tap, double-click or gesture) when
 visible.</p>

 <p>Recents function, if provided, MUST have a visible button or icon unless hidden
 together with other navigation functions in full-screen mode. This does not
 apply to devices upgrading from earlier Android versions that have physical
 buttons for navigation and no recents key.</p>

 <p> The Home and Back functions, if provided, MUST each have a visible button or
 icon unless hidden together with other navigation functions in full-screen mode
 or when the uiMode UI_MODE_TYPE_MASK is set to UI_MODE_TYPE_WATCH.</p>

 <p>The Menu function is deprecated in favor of action bar since Android 4.0.
 Therefore the new device implementations shipping with Android ANDROID_VERSION and later MUST NOT
 implement a dedicated physical button for the Menu function. Older device
 implementations SHOULD NOT implement a dedicated physical button for the Menu
 function, but if the physical Menu button is implemented and the device is
 running applications with targetSdkVersion > 10, the device implementation:</p>

 <ul>
   <li>MUST display the action overflow button on the action bar when it is visible
 and the resulting action overflow menu popup is not empty. For a device
 implementation launched before Android 4.4 but upgrading to Android ANDROID_VERSION, this
 is RECOMMENDED.</li>
   <li>MUST NOT modify the position of the action overflow popup displayed by
 selecting the overflow button in the action bar.</li>
   <li>MAY render the action overflow popup at a modified position on the screen when
 it is displayed by selecting the physical menu button.</li>
 </ul>

 <p>For backwards compatibility, device implementations MUST make the Menu function
 available to applications when targetSdkVersion is less than 10, either by a physical
 button, a software key, or gestures. This Menu function should be presented
 unless hidden together with other navigation functions.</p>

 <p>Android supports Assist action [<a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">Resources, 69</a>]. Android device implementations except for Android Watch devices MUST make
 the Assist action available to the user at all times when running applications.
 The Assist action SHOULD be implemented as a long-press on the Home button or a
 swipe-up gesture on the software Home key. This function MAY be implemented via
 another physical button, software key, or gesture, but MUST be accessible with
 a single action (e.g. tap, double-click, or gesture) when other navigation keys
 are visible.</p>

 <p>Device implementations MAY use a distinct portion of the screen to display the
 navigation keys, but if so, MUST meet these requirements:</p>

 <ul>
   <li>Device implementation navigation keys MUST use a distinct portion of the
 screen, not available to applications, and MUST NOT obscure or otherwise
 interfere with the portion of the screen available to applications.</li>
   <li>Device implementations MUST make available a portion of the display to
 applications that meets the requirements defined in <a href="#7_1_1_screen_configuration">section 7.1.1</a>.</li>
   <li>Device implementations MUST display the navigation keys when applications do
 not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE.</li>