944167 - Updating of return value of opensl_stream_get_position() is not often in gonk

Status: RESOLVED INACTIVE

(Core :: Audio/Video: Playback, defect)

Description

[Sotaro Ikeda [:sotaro]]

+++ This bug was initially created as a clone of Bug #933376 +++

This bug is created based on Bug 933376 Comment 24.

AudioClock::GetPosition() uses opensl_stream_get_position() to control audio clock. And opensl_stream_get_position() internally uses AudioTrack::getPosition() to get played audio duration.  AudioTrack::getPosition()'s value is used for audio clock. Therefore the value needs to be updated often. But in gonk, it's update is not often. Updated just release the audio buffer.

On ICS, it is tringger by AudioFlinger::ThreadBase::TrackBase::releaseBuffer(). 

http://androidxref.com/4.0.4/xref/frameworks/base/services/audioflinger/AudioFlinger.cpp#3289

Comment 1

[Sotaro Ikeda [:sotaro]]

This is a known problem in android.

Comment 2

[Sotaro Ikeda [:sotaro]]

Therefore android stagefright compensate audio time between buffer releases by using system time. It is done in AudioPlayer::getMediaTimeUs().
http://androidxref.com/4.4_r1/xref/frameworks/av/media/libstagefright/AudioPlayer.cpp#741

To do it, client side need to detect audio buffer release timing. AudioTrack provides this api. But I ma not sure OpenSLES API provide this capability.

Comment 3

[Jason Smith [:jsmith]]

What's the user impact of this bug? Is it a regression?

Comment 4

[Sotaro Ikeda [:sotaro]]

This is not a regression. It is same as in v1.1. It could affect to precise audio timing control. In current use cases this problem does not make a big problem. After supporting WebAudio, music and game applications/contents are going to use audio capability more. And it could affect to the audio control's quality.

I think it is not urgent necessity. So, I changed the '1.3?' to 'madai?'.

Comment 5

[Sotaro Ikeda [:sotaro]]

(In reply to Sotaro Ikeda [:sotaro] from comment #2)
> 
> To do it, client side need to detect audio buffer release timing. AudioTrack
> provides this api. But I ma not sure OpenSLES API provide this capability.

bufferqueue_callback() might be used if gecko do a similar thing.
http://mxr.mozilla.org/mozilla-central/source/media/libcubeb/src/cubeb_opensl.c

Comment 6

[Wayne Chang [:wchang]]

Retiring the madai flag, updating nomination for triage.

Comment 7

[Jason Smith [:jsmith]]

This has been around for multiple releases, so we will not block on this.

Comment 8

[Naoki Hirata :nhirata (please use needinfo instead of cc)]

Would this cause a crash?

https://crash-stats.mozilla.com/report/index/08e78fd5-3c7a-406d-b6ae-672752140630

Comment 9

[Nils Ohlmeier [:drno]]

Mass closing do to inactivity.
Feel free to re-open if still needed.