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| -rwxr-xr-x | src/compatibility/4.0/android-4.0-cdd.pdf | bin | 196829 -> 296639 bytes | |||
| -rw-r--r-- | src/compatibility/4.1/android-4.1-cdd.pdf | bin | 206285 -> 312797 bytes | |||
| -rwxr-xr-x | src/compatibility/4.2/android-4.2-cdd.pdf | bin | 215120 -> 331741 bytes | |||
| -rw-r--r-- | src/compatibility/android-4.0-cdd.pdf | bin | 196829 -> 296639 bytes | |||
| -rw-r--r--[-rwxr-xr-x] | src/compatibility/android-4.1-cdd.pdf | bin | 206285 -> 312797 bytes | |||
| -rw-r--r--[-rwxr-xr-x] | src/compatibility/android-4.2-cdd.pdf | bin | 215120 -> 331741 bytes | |||
| -rw-r--r-- | src/devices/audio_preprocessing.jd | 111 | ||||
| -rw-r--r-- | src/devices/audio_terminology.jd | 39 | ||||
| -rw-r--r-- | src/source/code-style.jd | 2 |
9 files changed, 40 insertions, 112 deletions
diff --git a/src/compatibility/4.0/android-4.0-cdd.pdf b/src/compatibility/4.0/android-4.0-cdd.pdf Binary files differindex f6c06a57..3de021a2 100755 --- a/src/compatibility/4.0/android-4.0-cdd.pdf +++ b/src/compatibility/4.0/android-4.0-cdd.pdf diff --git a/src/compatibility/4.1/android-4.1-cdd.pdf b/src/compatibility/4.1/android-4.1-cdd.pdf Binary files differindex 46b64822..270a2d0e 100644 --- a/src/compatibility/4.1/android-4.1-cdd.pdf +++ b/src/compatibility/4.1/android-4.1-cdd.pdf diff --git a/src/compatibility/4.2/android-4.2-cdd.pdf b/src/compatibility/4.2/android-4.2-cdd.pdf Binary files differindex 10addf35..f61708d4 100755 --- a/src/compatibility/4.2/android-4.2-cdd.pdf +++ b/src/compatibility/4.2/android-4.2-cdd.pdf diff --git a/src/compatibility/android-4.0-cdd.pdf b/src/compatibility/android-4.0-cdd.pdf Binary files differindex f6c06a57..3de021a2 100644 --- a/src/compatibility/android-4.0-cdd.pdf +++ b/src/compatibility/android-4.0-cdd.pdf diff --git a/src/compatibility/android-4.1-cdd.pdf b/src/compatibility/android-4.1-cdd.pdf Binary files differindex 46b64822..270a2d0e 100755..100644 --- a/src/compatibility/android-4.1-cdd.pdf +++ b/src/compatibility/android-4.1-cdd.pdf diff --git a/src/compatibility/android-4.2-cdd.pdf b/src/compatibility/android-4.2-cdd.pdf Binary files differindex 10addf35..f61708d4 100755..100644 --- a/src/compatibility/android-4.2-cdd.pdf +++ b/src/compatibility/android-4.2-cdd.pdf diff --git a/src/devices/audio_preprocessing.jd b/src/devices/audio_preprocessing.jd deleted file mode 100644 index 4beb7e0d..00000000 --- a/src/devices/audio_preprocessing.jd +++ /dev/null @@ -1,111 +0,0 @@ -page.title=Audio Warmup -@jd:body - -<!-- - Copyright 2010 The Android Open Source Project - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. ---> -<div id="qv-wrapper"> - <div id="qv"> - <h2>In this document</h2> - <ol id="auto-toc"> - </ol> - </div> -</div> - -<p>Audio warmup is the time for the audio amplifier circuit in your device to -be fully powered and reach its normal operation state. The major contributors -to audio warmup time are power management and any "de-pop" logic to stabilize -the circuit. -</p> - -<p>This document describes how to measure audio warmup time and possible ways to decrease -warmup time.</p> - -<h2 id="measuringOutput">Measuring Output Warmup</h2> - -<p> - AudioFlinger's FastMixer thread automatically measures output warmup - and reports it as part of the output of the <code>dumpsys media.audio_flinger</code> command. - At warmup, FastMixer calls <code>write()</code> - repeatedly until the time between two <code>write()</code>s is the amount expected. - FastMixer determines audio warmup by seeing how long a HAL <code>write()</code> takes to stabilize. -</p> - -<p>To measure audio warmup, do the following -steps for the built-in speaker and wired headphones and at different times after booting. -Warmup times are usually different for each output device and right after booting the device:</p> - -<ol> - <li>Ensure that FastMixer is enabled.</li> - <li>Enable touch sounds by selecting <b>Settings > Sound > Touch sounds</b> on the device.</li> - <li>Ensure that audio has been off for at least three seconds. Five seconds or more is better, because - the hardware itself might have its own power logic beyond the three seconds that AudioFlinger has.</li> - <li>Press Home, and you should hear a click sound.</li> - <li>Run the following command to receive the measured warmup: - <pre>adb shell dumpsys media.audio_flinger | grep measuredWarmup</code></pre> - -<p> -You should see output like this: -</p> - -<pre> -sampleRate=44100 frameCount=256 measuredWarmup=X ms, warmupCycles=X -</pre> - -<p> - The <code>measuredWarmup=X</code> is X number of milliseconds - it took for the first set of HAL <code>write()</code>s to complete. -</p> - -<p> - The <code>warmupCycles=X</code> is how many HAL write requests it took - until the execution time of <code>write()</code> matches what is expected. -</p> -</li> -<li> - Take five measurements and report them all, as well as the mean. - If they are not all approximately the same, - then it’s likely that a measurement is incorrect. - For example, if you don’t wait long enough after the audio has been off, - you will see a lower warmup time than the mean value. -</li> -</ol> - - -<h2 id="measuringInput">Measuring Input Warmup</h2> - -<p> - There are currently no tools provided for measuring audio input warmup. - However, input warmup time can be estimated by observing - the time required for <a href="http://developer.android.com/reference/android/media/AudioRecord.html#startRecording()">startRecording()</a> - to return. -</p> - - -<h2 id="reducing">Reducing Warmup Time</h2> - -<p> - Warmup time can usually be reduced by a combination of: - <ul> - <li>Good circuit design</li> - <li>Accurate time delays in kernel device driver</li> - <li>Performing independent warmup operations concurrently rather than sequentially</li> - <li>Leaving circuits powered on or not reconfiguring clocks (increases idle power consumption). - <li>Caching computed parameters</li> - </ul> - However, beware of excessive optimization. You may find that you - need to tradeoff between low warmup time versus - lack of popping at power transitions. -</p> diff --git a/src/devices/audio_terminology.jd b/src/devices/audio_terminology.jd index f6258502..eee03aaa 100644 --- a/src/devices/audio_terminology.jd +++ b/src/devices/audio_terminology.jd @@ -23,6 +23,13 @@ These are audio terms that are widely used, with their conventional meanings. <dl> +<dt>acoustics</dt> +<dd> +The study of the mechanical properties of sound, for example how the +physical placement of transducers such as speakers and microphones on +a device affects perceived audio quality. +</dd> + <dt>bits per sample or bit depth</dt> <dd> Number of bits of information per sample. @@ -45,6 +52,16 @@ The number of frames handed from one module to the next at once; for example the audio HAL interface uses this concept. </dd> +<dt>Hz</dt> +<dd> +The units for sample rate or frame rate. +</dd> + +<dt>latency</dt> +<dd> +Time delay as a signal passes through a system. +</dd> + <dt>mono</dt> <dd> One channel. @@ -89,6 +106,13 @@ to the kernel audio framework and drivers, not to the user-mode API. See tinyalsa. </dd> +<dt>AudioEffect</dt> +<dd> +An API and implementation framework for output (post-processing) effects +and input (pre-processing) effects. The API is defined at +<a class="external-link" href="http://developer.android.com/reference/android/media/audiofx/AudioEffect.html" target="_android">android.media.audiofx.AudioEffect</a> +</dd> + <dt>AudioFlinger</dt> <dd> The sound server implementation for Android. AudioFlinger @@ -166,6 +190,13 @@ A higher-level client API than AudioTrack, for playing either encoded content, or content which includes multi-media audio and video tracks. </dd> +<dt>media.log</dt> +<dd> +An AudioFlinger debugging feature, available in custom builds only, +for logging audio events to a circular buffer where they can then be +dumped retroactively when needed. +</dd> + <dt>mediaserver</dt> <dd> An Android system process that contains a number of media-related @@ -201,6 +232,14 @@ among threads. Whereas NBAIO is used to pass data, StateQueue is used to pass control information. </dd> +<dt>tee sink</dt> +<dd> +An AudioFlinger debugging feature, available in custom builds only, +for retaining a short fragment of recent audio for later analysis. +This permits comparison between what was actually played or recorded +vs. what was expected. +</dd> + <dt>tinyalsa</dt> <dd> A small user-mode API above ALSA kernel with BSD license, recommended diff --git a/src/source/code-style.jd b/src/source/code-style.jd index bb633fbe..99bfbb32 100644 --- a/src/source/code-style.jd +++ b/src/source/code-style.jd @@ -378,7 +378,7 @@ extra engineering effort.</p> <p>The use and location of static imports have been mildly controversial issues. Some people would prefer static imports to be interspersed with the remaining imports, some would prefer them reside above or below all other -imports. Additinally, we have not yet come up with a way to make all IDEs use +imports. Additionally, we have not yet come up with a way to make all IDEs use the same ordering.</p> <p>Since most people consider this a low priority issue, just use your judgement and please be consistent.</p> |