docs: adding content on persistent audioeffects. b/17508564
and fixing "exlains" typo in first para
and adding content on audio attributes (new page)
Change-Id: Id2322c0950dcbacfc66f249f41225ffb8d6d1257
diff --git a/src/devices/audio_implement.jd b/src/devices/audio_implement.jd
index 26aa5f5..0829e12 100644
--- a/src/devices/audio_implement.jd
+++ b/src/devices/audio_implement.jd
@@ -25,7 +25,7 @@
</div>
<p>
- This page exlains how to implement the audio Hardware Abstraction Layer (HAL)
+ This page explains how to implement the audio Hardware Abstraction Layer (HAL)
and configure the shared library.
</p>
@@ -194,7 +194,7 @@
</ul>
-<p>Pre-processing effects are always paired with the use case mode in which the pre-processing is requested. In Android
+<p>Pre-processing effects are paired with the use case mode in which the pre-processing is requested. In Android
app development, a use case is referred to as an <code>AudioSource</code>; and app developers
request to use the <code>AudioSource</code> abstraction instead of the actual audio hardware device.
The Android Audio Policy Manager maps an <code>AudioSource</code> to the actual hardware with <code>AudioPolicyManagerBase::getDeviceForInputSource(int
@@ -211,11 +211,11 @@
<li><code>android.media.MediaRecorder.AudioSource.DEFAULT</code></li>
</ul>
-<p>The default pre-processing effects that are applied for each <code>AudioSource</code> are
+<p>The default pre-processing effects applied for each <code>AudioSource</code> are
specified in the <code>/system/etc/audio_effects.conf</code> file. To specify
your own default effects for every <code>AudioSource</code>, create a <code>/system/vendor/etc/audio_effects.conf</code> file
-and specify any pre-processing effects that you need to turn on. For an example,
-see the implementation for the Nexus 10 in <code>device/samsung/manta/audio_effects.conf</code></p>
+and specify the pre-processing effects to turn on. For an example,
+see the implementation for the Nexus 10 in <code>device/samsung/manta/audio_effects.conf</code>. AudioEffect instances acquire and release a session when created and destroyed, enabling the effects (such as the Loudness Enhancer) to persist throughout the duration of the session.<p>
<p class="warning"><strong>Warning:</strong> For the <code>VOICE_RECOGNITION</code> use case, do not enable
the noise suppression pre-processing effect. It should not be turned on by default when recording from this audio source,