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| author | Clay Murphy <claym@google.com> | 2013-09-25 16:13:40 -0700 |
|---|---|---|
| committer | Clay Murphy <claym@google.com> | 2013-09-25 16:13:40 -0700 |
| commit | c28f237dd66f3826b36b51dbdea57411b9585869 (patch) | |
| tree | 4a295c73957b9b4b6192789825886f0fcfddf538 /src/devices/audio_warmup.jd | |
| parent | 8936ac54f3ee3ba25efe901b1667fcaf402cb0c7 (diff) | |
| download | source.android.com-c28f237dd66f3826b36b51dbdea57411b9585869.tar.gz | |
Docs: Starting updates for the K release.
Bug: 9391856
Staging location: http://claym.mtv.corp.google.com:8088/devices/audio.html
Change-Id: I58629ae54270ec949a47258ce63eae9643843deb
Diffstat (limited to 'src/devices/audio_warmup.jd')
| -rw-r--r-- | src/devices/audio_warmup.jd | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/src/devices/audio_warmup.jd b/src/devices/audio_warmup.jd index 4beb7e0d..ba1217cd 100644 --- a/src/devices/audio_warmup.jd +++ b/src/devices/audio_warmup.jd @@ -40,12 +40,13 @@ warmup time.</p> 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. + FastMixer determines audio warmup by seeing how long a Hardware Abstraction +Layer (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> +<p>To measure audio warmup, follow these 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> @@ -75,7 +76,7 @@ sampleRate=44100 frameCount=256 measuredWarmup=X ms, warmupCycles=X </p> </li> <li> - Take five measurements and report them all, as well as the mean. + Take five measurements and record 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, @@ -102,7 +103,7 @@ sampleRate=44100 frameCount=256 measuredWarmup=X ms, warmupCycles=X <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>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 |