5.5. Audio Playback

Android includes the support to allow apps to playback audio through the audio output peripheral as defined in section 7.8.2.

5.5.1. Raw Audio Playback

If device implementations declare android.hardware.audio.output, they:

• [C-1-1] MUST allow playback of raw audio content with the following characteristics:

  • Source formats: Linear PCM, 16-bit, 8-bit, float
  • Channels: Mono, Stereo, valid multichannel configurations with up to 8 channels
  • Sampling rates (in Hz):
    • 8000, 11025, 16000, 22050, 32000, 44100, 48000 at the channel configurations listed above
    • 96000 in mono and stereo

• SHOULD allow playback of raw audio content with the following characteristics:

  • Sampling rates: 24000, 48000

5.5.2. Audio Effects

Android provides an API for audio effects for device implementations.

If device implementations declare the feature android.hardware.audio.output, they:

• [C-1-1] MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER implementations controllable through the AudioEffect subclasses Equalizer and LoudnessEnhancer.
• [C-1-2] MUST support the visualizer API implementation, controllable through the Visualizer class.
• [C-1-3] MUST support the EFFECT_TYPE_DYNAMICS_PROCESSING implementation controllable through the AudioEffect subclass DynamicsProcessing.
• 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.
• [C-SR] Are STRONGLY RECOMMENDED to support effects in floating-point and multichannel.

5.5.3. Audio Output Volume

Automotive device implementations:

• SHOULD allow adjusting audio volume separately per each audio stream using the content type or usage as defined by AudioAttributes and car audio usage as publicly defined in android.car.CarAudioManager.