AudioTrack: get/setStartThresholdInFrames
setStartThresholdInFrames is used to set the start threshold
in frames for streaming AudioTrack playback.
Normally this is the entire buffer capacity in frames
but may be reduced for low latency playback,
compressed formats, and direct tracks.
Test: atest AudioTrackTest#testStartThresholdInFrames
Test: atest AudioTrackTest#testStartThresholdInFramesExceptions
Bug: 183003720
Merged-In: Iae10764130160de2380477134df27c5b139468bc
Change-Id: Iae10764130160de2380477134df27c5b139468bc
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index eec01ec..fb43a6e 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -638,7 +638,6 @@
mOpPlayAudioMonitor(OpPlayAudioMonitor::createIfNeeded(
uid, attr, id(), streamType, opPackageName)),
// mSinkTimestamp
- mFrameCountToBeReady(frameCountToBeReady),
mFastIndex(-1),
mCachedVolume(1.0),
/* The track might not play immediately after being active, similarly as if its volume was 0.
@@ -672,6 +671,7 @@
mFrameSize, sampleRate);
}
mServerProxy = mAudioTrackServerProxy;
+ mServerProxy->setStartThresholdInFrames(frameCountToBeReady); // update the Cblk value
// only allocate a fast track index if we were able to allocate a normal track name
if (flags & AUDIO_OUTPUT_FLAG_FAST) {
@@ -999,7 +999,10 @@
}
size_t bufferSizeInFrames = mServerProxy->getBufferSizeInFrames();
- size_t framesToBeReady = std::min(mFrameCountToBeReady, bufferSizeInFrames);
+ // Note: mServerProxy->getStartThresholdInFrames() is clamped.
+ const size_t startThresholdInFrames = mServerProxy->getStartThresholdInFrames();
+ const size_t framesToBeReady = std::clamp( // clamp again to validate client values.
+ std::min(startThresholdInFrames, bufferSizeInFrames), size_t(1), mFrameCount);
if (framesReady() >= framesToBeReady || (mCblk->mFlags & CBLK_FORCEREADY)) {
ALOGV("%s(%d): consider track ready with %zu/%zu, target was %zu)",