Merge "docs: Add article on batterstats, create power dir."
diff --git a/src/devices/audio/index.jd b/src/devices/audio/index.jd
index b658e85..bfa616d 100644
--- a/src/devices/audio/index.jd
+++ b/src/devices/audio/index.jd
@@ -25,88 +25,106 @@
</div>
</div>
-<img style="float: right; margin: 0px 15px 15px 15px;" src="images/ape_fwk_hal_audio.png" alt="Android Audio HAL icon"/>
+<img style="float: right; margin: 0px 15px 15px 15px;"
+src="images/ape_fwk_hal_audio.png" alt="Android Audio HAL icon"/>
+
<p>
- Android's audio Hardware Abstraction Layer (HAL) connects the higher-level, audio-specific
- framework APIs in <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> to the underlying audio driver and hardware. This section includes implementation instructions and tips for improving performance.</p>
+Android's audio Hardware Abstraction Layer (HAL) connects the higher-level,
+audio-specific framework APIs in <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> to the underlying audio driver and
+hardware. This section includes implementation instructions and tips for
+improving performance.
</p>
+
<h2 id="Architecture">Audio Architecture</h2>
<p>
- The following figure and list describe how audio functionality is implemented and the relevant
- source code that is involved in the implementation:
+Android audio architecture defines how audio functionality is implemented and
+points to the relevant source code involved in the implementation.
</p>
- <img src="images/ape_fwk_audio.png" alt="Audio architecture" id="figure1" />
+
+<img src="images/ape_fwk_audio.png" alt="Audio architecture" id="figure1" />
+
<p class="img-caption">
- <strong>Figure 1.</strong> Android audio architecture
+<strong>Figure 1.</strong> Android audio architecture
</p>
+
<dl>
- <dt>
- Application framework
- </dt>
- <dd>
- At the application framework level is the app code, which utilizes the
- <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a>
- APIs to interact with the audio hardware. Internally, this code calls corresponding JNI glue
- classes to access the native code that interacts with the audio hardware.
- </dd>
- <dt>
- JNI
- </dt>
- <dd>
- The JNI code associated with <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> is located in the
- <code>frameworks/base/core/jni/</code> and <code>frameworks/base/media/jni</code> directories.
- This code calls the lower level native code to obtain access to the audio hardware.
- </dd>
- <dt>
- Native framework
- </dt>
- <dd>
- The native framework is defined in <code>frameworks/av/media/libmedia</code> and provides a
- native equivalent to the <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> package. The native framework calls the Binder
- IPC proxies to obtain access to audio-specific services of the media server.
- </dd>
- <dt>
- Binder IPC
- </dt>
- <dd>
- The Binder IPC proxies facilitate communication over process boundaries. They are located in
- the <code>frameworks/av/media/libmedia</code> directory and begin with the letter "I".
- </dd>
- <dt>
- Media Server
- </dt>
- <dd>
- The audio services in the media server, located in
- <code>frameworks/av/services/audioflinger</code>, is the actual code that interacts with your
- HAL implementations.
- </dd>
- <dt>
- HAL
- </dt>
- <dd>
- The HAL defines the standard interface that audio services call into
- and that you must implement to have your audio hardware function correctly. The audio HAL
- interfaces are located in
-<code>hardware/libhardware/include/hardware</code>. See <a
-href="{@docRoot}devices/halref/audio_8h_source.html"><hardware/audio.h></a> for additional details.
- </dd>
- <dt>
- Kernel Driver
- </dt>
- <dd>
- The audio driver interacts with the hardware and your implementation of the HAL. You can choose
- to use ALSA, OSS, or a custom driver of your own at this level. The HAL is driver-agnostic.
- <p>
- <strong>Note:</strong> If you do choose ALSA, we recommend using <code>external/tinyalsa</code>
- for the user portion of the driver because of its compatible licensing (The standard user-mode
- library is GPL licensed).
-</p>
- </dd>
-</dl>
-<p>
-Not shown: Android native audio based on OpenSL ES.
+
+<dt>
+Application framework
+</dt>
+<dd>
+The application framework includes the app code, which uses the <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> APIs to
+interact with audio hardware. Internally, this code calls corresponding JNI glue
+classes to access the native code that interacts with audio hardware.
+</dd>
+
+<dt>
+JNI
+</dt>
+<dd>
+The JNI code associated with <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> calls lower level native code to access audio
+hardware. JNI is located in <code>frameworks/base/core/jni/</code> and
+<code>frameworks/base/media/jni</code>.
+</dd>
+
+<dt>
+Native framework
+</dt>
+<dd>
+The native framework provides a native equivalent to the <a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a> package, calling
+Binder IPC proxies to access the audio-specific services of the media server.
+Native framework code is located in <code>frameworks/av/media/libmedia</code>.
+</dd>
+
+<dt>
+Binder IPC
+</dt>
+<dd>
+Binder IPC proxies facilitate communication over process boundaries. Proxies are
+located in <code>frameworks/av/media/libmedia</code> and begin with the letter
+"I".
+</dd>
+
+<dt>
+Media server
+</dt>
+<dd>
+The media server contains audio services, which are the actual code that
+interacts with your HAL implementations. The media server is located in
+<code>frameworks/av/services/audioflinger</code>.
+</dd>
+
+<dt>
+HAL
+</dt>
+<dd>
+The HAL defines the standard interface that audio services call into and that
+you must implement for your audio hardware to function correctly. The audio HAL
+interfaces are located in <code>hardware/libhardware/include/hardware</code>.
+For details, see <a
+href="{@docRoot}devices/halref/audio_8h_source.html">hardware/audio.h</a>.
+</dd>
+
+<dt>
+Kernel driver
+</dt>
+<dd>
+The audio driver interacts with your hardware and HAL implementation. You can
+use Advanced Linux Sound Architecture (ALSA), Open Sound System (OSS), or a
+custom driver (HAL is driver-agnostic).
+<p class="note"><strong>Note</strong>: If you use ALSA, we recommend
+<code>external/tinyalsa</code> for the user portion of the driver because of its
+compatible licensing (the standard user-mode library is GPL-licensed).</p>
+</dd>
+
+<dt>
+Android native audio based on Open SL ES <em>(not shown)</em>
+</dt>
+<dd>
This API is exposed as part of
-<a href="https://developer.android.com/tools/sdk/ndk/index.html">Android NDK</a>,
+<a href="https://developer.android.com/tools/sdk/ndk/index.html">Android NDK</a>
and is at the same architecture level as
<a href="http://developer.android.com/reference/android/media/package-summary.html">android.media</a>.
-</p>
\ No newline at end of file
+</dd>
+
+</dl>
\ No newline at end of file
