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Issue 3032913: improve AudioTrack recovery time

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This issue showed that when an AudioTrack underruns during a too long period
of time and is therefore disabled by audioflinger mixer, it takes an additional
delay of up to 3 seconds to recover.
This fix adds a simple mechanism to recover immediately when the client application
is ready to write data again in the AudioTrack buffer

Also throttle warnings on record overflows

Change-Id: I8b2c71578dd134b9e60a15ee4d91b70f3799cb3d
This commit is contained in:
Eric Laurent
2010-09-30 16:12:31 -07:00
parent 0a972acf85
commit 4712baab81
3 changed files with 26 additions and 6 deletions
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7
include/private/media/AudioTrackShared.h
View File

@@ -42,8 +42,11 @@ namespace android {
#define CBLK_FORCEREADY_ON 0x0004 // track is considered ready immediately by AudioFlinger
#define CBLK_FORCEREADY_OFF 0x0000 // track is ready when buffer full
#define CBLK_INVALID_MSK 0x0008
#define CBLK_INVALID_ON 0x0008 // track buffer is invalidated by AudioFlinger: must be re-created
#define CBLK_INVALID_OFF 0x0000
#define CBLK_INVALID_ON 0x0008 // track buffer is invalidated by AudioFlinger:
#define CBLK_INVALID_OFF 0x0000 // must be re-created
#define CBLK_DISABLED_MSK 0x0010
#define CBLK_DISABLED_ON 0x0010 // track disabled by AudioFlinger due to underrun:
#define CBLK_DISABLED_OFF 0x0000 // must be re-started
struct audio_track_cblk_t
{

8
media/libmedia/AudioTrack.cpp
View File

@@ -316,6 +316,7 @@ void AudioTrack::start()
mNewPosition = mCblk->server + mUpdatePeriod;
mCblk->bufferTimeoutMs = MAX_STARTUP_TIMEOUT_MS;
mCblk->waitTimeMs = 0;
mCblk->flags &= ~CBLK_DISABLED_ON;
if (t != 0) {
t->run("AudioTrackThread", THREAD_PRIORITY_AUDIO_CLIENT);
} else {
@@ -842,6 +843,13 @@ create_new_track:
cblk->lock.unlock();
}
// restart track if it was disabled by audioflinger due to previous underrun
if (cblk->flags & CBLK_DISABLED_MSK) {
cblk->flags &= ~CBLK_DISABLED_ON;
LOGW("obtainBuffer() track %p disabled, restarting", this);
mAudioTrack->start();
}
cblk->waitTimeMs = 0;
if (framesReq > framesAvail) {

17
services/audioflinger/AudioFlinger.cpp
View File

@@ -1856,6 +1856,8 @@ uint32_t AudioFlinger::MixerThread::prepareTracks_l(const SortedVector< wp<Track
if (--(track->mRetryCount) <= 0) {
LOGV("BUFFER TIMEOUT: remove(%d) from active list on thread %p", track->name(), this);
tracksToRemove->add(track);
// indicate to client process that the track was disabled because of underrun
cblk->flags |= CBLK_DISABLED_ON;
} else if (mixerStatus != MIXER_TRACKS_READY) {
mixerStatus = MIXER_TRACKS_ENABLED;
}
@@ -2790,7 +2792,7 @@ AudioFlinger::ThreadBase::TrackBase::TrackBase(
mBuffer = (char*)mCblk + sizeof(audio_track_cblk_t);
memset(mBuffer, 0, frameCount*channelCount*sizeof(int16_t));
// Force underrun condition to avoid false underrun callback until first data is
// written to buffer
// written to buffer (other flags are cleared)
mCblk->flags = CBLK_UNDERRUN_ON;
} else {
mBuffer = sharedBuffer->pointer();
@@ -2813,7 +2815,7 @@ AudioFlinger::ThreadBase::TrackBase::TrackBase(
mBuffer = (char*)mCblk + sizeof(audio_track_cblk_t);
memset(mBuffer, 0, frameCount*channelCount*sizeof(int16_t));
// Force underrun condition to avoid false underrun callback until first data is
// written to buffer
// written to buffer (other flags are cleared)
mCblk->flags = CBLK_UNDERRUN_ON;
mBufferEnd = (uint8_t *)mBuffer + bufferSize;
}
@@ -3794,6 +3796,8 @@ bool AudioFlinger::RecordThread::threadLoop()
AudioBufferProvider::Buffer buffer;
sp<RecordTrack> activeTrack;
nsecs_t lastWarning = 0;
// start recording
while (!exitPending()) {
@@ -3935,8 +3939,13 @@ bool AudioFlinger::RecordThread::threadLoop()
}
// client isn't retrieving buffers fast enough
else {
if (!mActiveTrack->setOverflow())
LOGW("RecordThread: buffer overflow");
if (!mActiveTrack->setOverflow()) {
nsecs_t now = systemTime();
if ((now - lastWarning) > kWarningThrottle) {
LOGW("RecordThread: buffer overflow");
lastWarning = now;
}
}
// Release the processor for a while before asking for a new buffer.
// This will give the application more chance to read from the buffer and
// clear the overflow.