Bug 1207915 - Apply the fix of bug 1052206 to DecodedStream. r=roc.

dom/media/mediasink/DecodedStream.cpp

@@ -605,6 +605,9 @@ SendStreamAudio(DecodedStreamData* aStream, int64_t aStartTime,
                 MediaData* aData, AudioSegment* aOutput,
                 uint32_t aRate, double aVolume)
 {
+  // The amount of audio frames that is used to fuzz rounding errors.
+  static const int64_t AUDIO_FUZZ_FRAMES = 1;
+
   MOZ_ASSERT(aData);
   AudioData* audio = aData->As<AudioData>();
   // This logic has to mimic AudioSink closely to make sure we write
@@ -616,11 +619,11 @@ SendStreamAudio(DecodedStreamData* aStream, int64_t aStartTime,
   if (!audioWrittenOffset.isValid() ||
       !frameOffset.isValid() ||
       // ignore packet that we've already processed
-      frameOffset.value() + audio->mFrames <= audioWrittenOffset.value()) {
+      frameOffset.value() < audioWrittenOffset.value()) {
     return;
   }
 
-  if (audioWrittenOffset.value() < frameOffset.value()) {
+  if (audioWrittenOffset.value() + AUDIO_FUZZ_FRAMES < frameOffset.value()) {
     int64_t silentFrames = frameOffset.value() - audioWrittenOffset.value();
     // Write silence to catch up
     AudioSegment silence;
@@ -630,20 +633,17 @@ SendStreamAudio(DecodedStreamData* aStream, int64_t aStartTime,
     aOutput->AppendFrom(&silence);
   }
 
-  MOZ_ASSERT(audioWrittenOffset.value() >= frameOffset.value());
-
-  int64_t offset = audioWrittenOffset.value() - frameOffset.value();
-  size_t framesToWrite = audio->mFrames - offset;
-
+  // Always write the whole sample without truncation to be consistent with
+  // DecodedAudioDataSink::PlayFromAudioQueue()
   audio->EnsureAudioBuffer();
   nsRefPtr<SharedBuffer> buffer = audio->mAudioBuffer;
   AudioDataValue* bufferData = static_cast<AudioDataValue*>(buffer->Data());
   nsAutoTArray<const AudioDataValue*, 2> channels;
   for (uint32_t i = 0; i < audio->mChannels; ++i) {
-    channels.AppendElement(bufferData + i * audio->mFrames + offset);
+    channels.AppendElement(bufferData + i * audio->mFrames);
   }
-  aOutput->AppendFrames(buffer.forget(), channels, framesToWrite);
-  aStream->mAudioFramesWritten += framesToWrite;
+  aOutput->AppendFrames(buffer.forget(), channels, audio->mFrames);
+  aStream->mAudioFramesWritten += audio->mFrames;
   aOutput->ApplyVolume(aVolume);
 
   aStream->mNextAudioTime = audio->GetEndTime();