AudioTrack: fix head position after restore
The head position transfered to the new track
by restoreTrack_l() must take into account the frames that
are dropped from the old track to avoid a non recoverable
offset in the playback head position returned to applications.
Bug: 11230062.
Change-Id: I51143a08b95e8f264ed709ae2054360315f2b8b1
diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h
index fe258ad..395f164 100644
--- a/include/private/media/AudioTrackShared.h
+++ b/include/private/media/AudioTrackShared.h
@@ -256,6 +256,8 @@
return mEpoch;
}
+ size_t getFramesFilled();
+
private:
size_t mEpoch;
};
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index 37d50cf..507f9bc 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -1662,7 +1662,9 @@
// if the new IAudioTrack is created, createTrack_l() will modify the
// following member variables: mAudioTrack, mCblkMemory and mCblk.
// It will also delete the strong references on previous IAudioTrack and IMemory
- size_t position = mProxy->getPosition();
+
+ // take the frames that will be lost by track recreation into account in saved position
+ size_t position = mProxy->getPosition() + mProxy->getFramesFilled();
mNewPosition = position + mUpdatePeriod;
size_t bufferPosition = mStaticProxy != NULL ? mStaticProxy->getBufferPosition() : 0;
result = createTrack_l(mStreamType,
diff --git a/media/libmedia/AudioTrackShared.cpp b/media/libmedia/AudioTrackShared.cpp
index 4fd92b2..da73d65 100644
--- a/media/libmedia/AudioTrackShared.cpp
+++ b/media/libmedia/AudioTrackShared.cpp
@@ -316,6 +316,27 @@
(mFrameCountP2 - 1);
}
+size_t ClientProxy::getFramesFilled() {
+ audio_track_cblk_t* cblk = mCblk;
+ int32_t front;
+ int32_t rear;
+
+ if (mIsOut) {
+ front = android_atomic_acquire_load(&cblk->u.mStreaming.mFront);
+ rear = cblk->u.mStreaming.mRear;
+ } else {
+ rear = android_atomic_acquire_load(&cblk->u.mStreaming.mRear);
+ front = cblk->u.mStreaming.mFront;
+ }
+ ssize_t filled = rear - front;
+ // pipe should not be overfull
+ if (!(0 <= filled && (size_t) filled <= mFrameCount)) {
+ ALOGE("Shared memory control block is corrupt (filled=%d); shutting down", filled);
+ return 0;
+ }
+ return (size_t)filled;
+}
+
// ---------------------------------------------------------------------------
void AudioTrackClientProxy::flush()