Bug 2065821 - Clear SoundTouch state when discarding future audio r=media-playback-reviewers,karlt

ClearFutureData discards raw decoded samples but previously retained
SoundTouch output derived from them. Clear its internal state too, so pause,
seek, and reset do not continue playing discarded audio.

Differential Revision: https://phabricator.services.mozilla.com/D320704

dom/media/mediasink/AudioDecoderInputTrack.cpp

@@ -353,6 +353,9 @@ void AudioDecoderInputTrack::HandleSPSCData(SPSCData& aData) {
   if (aData.IsClearFutureData()) {
     LOG("Clear future data");
     mBufferedData.Clear();
+    if (mTimeStretcher) {
+      mTimeStretcher->clear();
+    }
     if (!Ended()) {
       LOG("Clear EOS");
       mReceivedEOS = false;

media/libsoundtouch/src/RLBoxSoundTouch.cpp

@@ -151,6 +151,10 @@ uint RLBoxSoundTouch::receiveSamples(AudioDataValue* aOutput,
   return numWrittenSamples;
 }
 
+void RLBoxSoundTouch::clear() {
+  return mSandbox.invoke_sandbox_function(Clear, mTimeStretcher);
+}
+
 void RLBoxSoundTouch::flush() {
   return mSandbox.invoke_sandbox_function(Flush, mTimeStretcher);
 }

media/libsoundtouch/src/RLBoxSoundTouch.h

@@ -74,6 +74,8 @@ class RLBoxSoundTouch {
   RLBOX_SOUNDTOUCH_API
   uint receiveSamples(mozilla::AudioDataValue* aOutput, uint aMaxSamples);
   RLBOX_SOUNDTOUCH_API
+  void clear();
+  RLBOX_SOUNDTOUCH_API
   void flush();
 
   RLBOX_SOUNDTOUCH_API

media/libsoundtouch/src/RLBoxSoundTouchFactory.cpp

@@ -56,5 +56,7 @@ uint ReceiveSamples(SoundTouch* mTimeStretcher, SAMPLETYPE* output,
   return mTimeStretcher->receiveSamples(output, maxSamples);
 }
 
+void Clear(SoundTouch* mTimeStretcher) { mTimeStretcher->clear(); }
+
 void Flush(SoundTouch* mTimeStretcher) { return mTimeStretcher->flush(); }
 }

media/libsoundtouch/src/RLBoxSoundTouchFactory.h

@@ -22,5 +22,6 @@ void PutSamples(soundtouch::SoundTouch* mTimeStretcher,
                 const soundtouch::SAMPLETYPE* samples, uint numSamples);
 uint ReceiveSamples(soundtouch::SoundTouch* mTimeStretcher,
                     soundtouch::SAMPLETYPE* output, uint maxSamples);
+void Clear(soundtouch::SoundTouch* mTimeStretcher);
 void Flush(soundtouch::SoundTouch* mTimeStretcher);
 }