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-rw-r--r--dom/media/AudioCaptureTrack.cpp97
1 files changed, 97 insertions, 0 deletions
diff --git a/dom/media/AudioCaptureTrack.cpp b/dom/media/AudioCaptureTrack.cpp
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+++ b/dom/media/AudioCaptureTrack.cpp
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+/* -*- 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 "MediaTrackGraph.h"
+#include "MediaTrackListener.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/Unused.h"
+
+#include "AudioSegment.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Attributes.h"
+#include "AudioCaptureTrack.h"
+#include "ImageContainer.h"
+#include "AudioNodeEngine.h"
+#include "AudioNodeTrack.h"
+#include "AudioNodeExternalInputTrack.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;
+
+AudioCaptureTrack::AudioCaptureTrack(TrackRate aRate)
+ : ProcessedMediaTrack(aRate, MediaSegment::AUDIO, new AudioSegment()),
+ mStarted(false) {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_COUNT_CTOR(AudioCaptureTrack);
+}
+
+AudioCaptureTrack::~AudioCaptureTrack() { MOZ_COUNT_DTOR(AudioCaptureTrack); }
+
+void AudioCaptureTrack::Start() {
+ QueueControlMessageWithNoShutdown(
+ [self = RefPtr{this}, this] { mStarted = true; });
+}
+
+void AudioCaptureTrack::ProcessInput(GraphTime aFrom, GraphTime aTo,
+ uint32_t aFlags) {
+ if (!mStarted) {
+ return;
+ }
+
+ uint32_t inputCount = mInputs.Length();
+
+ if (mEnded) {
+ return;
+ }
+
+ // If the captured track is connected back to a object on the page (be it an
+ // HTMLMediaElement with a track as source, or an AudioContext), a cycle
+ // situation occur. This can work if it's an AudioContext with at least one
+ // DelayNode, but the MTG will mute the whole cycle otherwise.
+ if (InMutedCycle() || inputCount == 0) {
+ GetData<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++) {
+ MediaTrack* s = mInputs[i]->GetSource();
+ AudioSegment* inputSegment = s->GetData<AudioSegment>();
+ TrackTime inputStart = s->GraphTimeToTrackTimeWithBlocking(aFrom);
+ TrackTime inputEnd = s->GraphTimeToTrackTimeWithBlocking(aTo);
+ AudioSegment toMix;
+ if (s->Ended() && inputSegment->GetDuration() <= inputStart) {
+ toMix.AppendNullData(aTo - aFrom);
+ } else {
+ toMix.AppendSlice(*inputSegment, inputStart, inputEnd);
+ // Care for tracks blocked in the [aTo, aFrom] range.
+ if (inputEnd - inputStart < aTo - aFrom) {
+ toMix.AppendNullData((aTo - aFrom) - (inputEnd - inputStart));
+ }
+ }
+ toMix.Mix(mMixer, MONO, Graph()->GraphRate());
+ }
+ AudioChunk* mixed = mMixer.MixedChunk();
+ MOZ_ASSERT(mixed->ChannelCount() == MONO);
+ // Now we have mixed data, simply append it.
+ GetData<AudioSegment>()->AppendAndConsumeChunk(std::move(*mixed));
+ }
+}
+
+uint32_t AudioCaptureTrack::NumberOfChannels() const {
+ return GetData<AudioSegment>()->MaxChannelCount();
+}
+
+} // namespace mozilla