1 files changed, 169 insertions, 0 deletions
diff --git a/dom/media/AudioCaptureStream.cpp b/dom/media/AudioCaptureStream.cpp
new file mode 100644
index 000000000..c381ac621
--- /dev/null
+++ b/dom/media/AudioCaptureStream.cpp
@@ -0,0 +1,169 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaStreamGraphImpl.h"
+#include "MediaStreamListener.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/Unused.h"
+
+#include "AudioSegment.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Attributes.h"
+#include "AudioCaptureStream.h"
+#include "ImageContainer.h"
+#include "AudioNodeEngine.h"
+#include "AudioNodeStream.h"
+#include "AudioNodeExternalInputStream.h"
+#include "webaudio/MediaStreamAudioDestinationNode.h"
+#include <algorithm>
+#include "DOMMediaStream.h"
+
+using namespace mozilla::layers;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+
+namespace mozilla
+{
+
+// We are mixing to mono until PeerConnection can accept stereo
+static const uint32_t MONO = 1;
+
+AudioCaptureStream::AudioCaptureStream(TrackID aTrackId)
+  : ProcessedMediaStream(), mTrackId(aTrackId), mStarted(false), mTrackCreated(false)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_COUNT_CTOR(AudioCaptureStream);
+  mMixer.AddCallback(this);
+}
+
+AudioCaptureStream::~AudioCaptureStream()
+{
+  MOZ_COUNT_DTOR(AudioCaptureStream);
+  mMixer.RemoveCallback(this);
+}
+
+void
+AudioCaptureStream::Start()
+{
+  class Message : public ControlMessage {
+  public:
+    explicit Message(AudioCaptureStream* aStream)
+      : ControlMessage(aStream), mStream(aStream) {}
+
+    virtual void Run()
+    {
+      mStream->mStarted = true;
+    }
+
+  protected:
+    AudioCaptureStream* mStream;
+  };
+  GraphImpl()->AppendMessage(MakeUnique<Message>(this));
+}
+
+void
+AudioCaptureStream::ProcessInput(GraphTime aFrom, GraphTime aTo,
+                                 uint32_t aFlags)
+{
+  if (!mStarted) {
+    return;
+  }
+
+  uint32_t inputCount = mInputs.Length();
+  StreamTracks::Track* track = EnsureTrack(mTrackId);
+  // Notify the DOM everything is in order.
+  if (!mTrackCreated) {
+    for (uint32_t i = 0; i < mListeners.Length(); i++) {
+      MediaStreamListener* l = mListeners[i];
+      AudioSegment tmp;
+      l->NotifyQueuedTrackChanges(
+        Graph(), mTrackId, 0, TrackEventCommand::TRACK_EVENT_CREATED, tmp);
+      l->NotifyFinishedTrackCreation(Graph());
+    }
+    mTrackCreated = true;
+  }
+
+  if (IsFinishedOnGraphThread()) {
+    return;
+  }
+
+  // If the captured stream is connected back to a object on the page (be it an
+  // HTMLMediaElement with a stream as source, or an AudioContext), a cycle
+  // situation occur. This can work if it's an AudioContext with at least one
+  // DelayNode, but the MSG will mute the whole cycle otherwise.
+  if (InMutedCycle() || inputCount == 0) {
+    track->Get<AudioSegment>()->AppendNullData(aTo - aFrom);
+  } else {
+    // We mix down all the tracks of all inputs, to a stereo track. Everything
+    // is {up,down}-mixed to stereo.
+    mMixer.StartMixing();
+    AudioSegment output;
+    for (uint32_t i = 0; i < inputCount; i++) {
+      MediaStream* s = mInputs[i]->GetSource();
+      StreamTracks::TrackIter track(s->GetStreamTracks(), MediaSegment::AUDIO);
+      if (track.IsEnded()) {
+        // No tracks for this input. Still we append data to trigger the mixer.
+        AudioSegment toMix;
+        toMix.AppendNullData(aTo - aFrom);
+        toMix.Mix(mMixer, MONO, Graph()->GraphRate());
+      }
+      for (; !track.IsEnded(); track.Next()) {
+        AudioSegment* inputSegment = track->Get<AudioSegment>();
+        StreamTime inputStart = s->GraphTimeToStreamTimeWithBlocking(aFrom);
+        StreamTime inputEnd = s->GraphTimeToStreamTimeWithBlocking(aTo);
+        AudioSegment toMix;
+        if (track->IsEnded() && inputSegment->GetDuration() <= inputStart) {
+          toMix.AppendNullData(aTo - aFrom);
+        } else {
+          toMix.AppendSlice(*inputSegment, inputStart, inputEnd);
+          // Care for streams blocked in the [aTo, aFrom] range.
+          if (inputEnd - inputStart < aTo - aFrom) {
+            toMix.AppendNullData((aTo - aFrom) - (inputEnd - inputStart));
+          }
+        }
+        toMix.Mix(mMixer, MONO, Graph()->GraphRate());
+      }
+    }
+    // This calls MixerCallback below
+    mMixer.FinishMixing();
+  }
+
+  // Regardless of the status of the input tracks, we go foward.
+  mTracks.AdvanceKnownTracksTime(GraphTimeToStreamTimeWithBlocking((aTo)));
+}
+
+void
+AudioCaptureStream::MixerCallback(AudioDataValue* aMixedBuffer,
+                                  AudioSampleFormat aFormat, uint32_t aChannels,
+                                  uint32_t aFrames, uint32_t aSampleRate)
+{
+  AutoTArray<nsTArray<AudioDataValue>, MONO> output;
+  AutoTArray<const AudioDataValue*, MONO> bufferPtrs;
+  output.SetLength(MONO);
+  bufferPtrs.SetLength(MONO);
+
+  uint32_t written = 0;
+  // We need to copy here, because the mixer will reuse the storage, we should
+  // not hold onto it. Buffers are in planar format.
+  for (uint32_t channel = 0; channel < aChannels; channel++) {
+    AudioDataValue* out = output[channel].AppendElements(aFrames);
+    PodCopy(out, aMixedBuffer + written, aFrames);
+    bufferPtrs[channel] = out;
+    written += aFrames;
+  }
+  AudioChunk chunk;
+  chunk.mBuffer = new mozilla::SharedChannelArrayBuffer<AudioDataValue>(&output);
+  chunk.mDuration = aFrames;
+  chunk.mBufferFormat = aFormat;
+  chunk.mVolume = 1.0f;
+  chunk.mChannelData.SetLength(MONO);
+  for (uint32_t channel = 0; channel < aChannels; channel++) {
+    chunk.mChannelData[channel] = bufferPtrs[channel];
+  }
+
+  // Now we have mixed data, simply append it to out track.
+  EnsureTrack(mTrackId)->Get<AudioSegment>()->AppendAndConsumeChunk(&chunk);
+}
+}