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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 */
#ifndef MediaEncoder_h_
#define MediaEncoder_h_
#include "ContainerWriter.h"
#include "CubebUtils.h"
#include "MediaQueue.h"
#include "MediaTrackGraph.h"
#include "MediaTrackListener.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/UniquePtr.h"
#include "nsIMemoryReporter.h"
#include "TrackEncoder.h"
namespace mozilla {
class DriftCompensator;
class Muxer;
class Runnable;
class TaskQueue;
namespace dom {
class AudioNode;
class AudioStreamTrack;
class MediaStreamTrack;
class VideoStreamTrack;
} // namespace dom
class DriftCompensator;
class MediaEncoder;
class MediaEncoderListener {
virtual void Initialized() = 0;
virtual void DataAvailable() = 0;
virtual void Error() = 0;
virtual void Shutdown() = 0;
virtual ~MediaEncoderListener() = default;
* MediaEncoder is the framework of encoding module, it controls and manages
* procedures between ContainerWriter and TrackEncoder. ContainerWriter packs
* the encoded track data with a specific container (e.g. ogg, webm).
* AudioTrackEncoder and VideoTrackEncoder are subclasses of TrackEncoder, and
* are responsible for encoding raw data coming from MediaTrackGraph.
* MediaEncoder solves threading issues by doing message passing to a TaskQueue
* (the "encoder thread") as passed in to the constructor. Each
* MediaStreamTrack to be recorded is set up with a MediaTrackListener.
* Typically there are a non-direct track listeners for audio, direct listeners
* for video, and there is always a non-direct listener on each track for
* time-keeping. The listeners forward data to their corresponding TrackEncoders
* on the encoder thread.
* The MediaEncoder listens to events from all TrackEncoders, and in turn
* signals events to interested parties. Typically a MediaRecorder::Session.
* The event that there's data available in the TrackEncoders is what typically
* drives the extraction and muxing of data.
* MediaEncoder is designed to be a passive component, neither does it own or is
* in charge of managing threads. Instead this is done by its owner.
* For example, usage from MediaRecorder of this component would be:
* 1) Create an encoder with a valid MIME type.
* => encoder = MediaEncoder::CreateEncoder(aMIMEType);
* It then creates a ContainerWriter according to the MIME type
* 2) Connect a MediaEncoderListener to be notified when the MediaEncoder has
* been initialized and when there's data available.
* => encoder->RegisterListener(listener);
* 3) Connect the sources to be recorded. Either through:
* => encoder->ConnectAudioNode(node);
* or
* => encoder->ConnectMediaStreamTrack(track);
* These should not be mixed. When connecting MediaStreamTracks there is
* support for at most one of each kind.
* 4) When the MediaEncoderListener is notified that the MediaEncoder has
* data available, we can encode data. This also encodes metadata on its
* first invocation.
* => encoder->GetEncodedData(...);
* 5) To stop encoding, there are multiple options:
* 5.1) Stop() for a graceful stop.
* => encoder->Stop();
* 5.2) Cancel() for an immediate stop, if you don't need the data currently
* buffered.
* => encoder->Cancel();
* 5.3) When all input tracks end, the MediaEncoder will automatically stop
* and shut down.
class MediaEncoder {
class AudioTrackListener;
class VideoTrackListener;
class EncoderListener;
MediaEncoder(TaskQueue* aEncoderThread,
RefPtr<DriftCompensator> aDriftCompensator,
UniquePtr<ContainerWriter> aWriter,
AudioTrackEncoder* aAudioEncoder,
VideoTrackEncoder* aVideoEncoder, TrackRate aTrackRate,
const nsAString& aMIMEType);
* Called on main thread from MediaRecorder::Pause.
void Suspend();
* Called on main thread from MediaRecorder::Resume.
void Resume();
* Stops the current encoding, and disconnects the input tracks.
void Stop();
* Connects an AudioNode with the appropriate encoder.
void ConnectAudioNode(dom::AudioNode* aNode, uint32_t aOutput);
* Connects a MediaStreamTrack with the appropriate encoder.
void ConnectMediaStreamTrack(dom::MediaStreamTrack* aTrack);
* Removes a connected MediaStreamTrack.
void RemoveMediaStreamTrack(dom::MediaStreamTrack* aTrack);
* Creates an encoder with a given MIME type. Returns null if we are unable
* to create the encoder. For now, default aMIMEType to "audio/ogg" and use
* Ogg+Opus if it is empty.
static already_AddRefed<MediaEncoder> CreateEncoder(
TaskQueue* aEncoderThread, const nsAString& aMIMEType,
uint32_t aAudioBitrate, uint32_t aVideoBitrate, uint8_t aTrackTypes,
TrackRate aTrackRate);
* Encodes raw data for all tracks to aOutputBufs. The buffer of container
* data is allocated in ContainerWriter::GetContainerData().
* On its first call, metadata is also encoded. TrackEncoders must have been
* initialized before this is called.
nsresult GetEncodedData(nsTArray<nsTArray<uint8_t>>* aOutputBufs);
* Asserts that Shutdown() has been called. Reasons are encoding
* complete, encounter an error, or being canceled by its caller.
void AssertShutdownCalled() { MOZ_ASSERT(mShutdownPromise); }
* Cancels the encoding and shuts down the encoder using Shutdown().
RefPtr<GenericNonExclusivePromise::AllPromiseType> Cancel();
bool HasError();
static bool IsWebMEncoderEnabled();
const nsString& MimeType() const;
* Notifies listeners that this MediaEncoder has been initialized.
void NotifyInitialized();
* Notifies listeners that this MediaEncoder has data available in some
* TrackEncoders.
void NotifyDataAvailable();
* Registers a listener to events from this MediaEncoder.
* We hold a strong reference to the listener.
void RegisterListener(MediaEncoderListener* aListener);
* Unregisters a listener from events from this MediaEncoder.
* The listener will stop receiving events synchronously.
bool UnregisterListener(MediaEncoderListener* aListener);
* Measure the size of the buffer, and heap memory in bytes occupied by
* mAudioEncoder and mVideoEncoder.
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf);
* Set desired video keyframe interval defined in milliseconds.
void SetVideoKeyFrameInterval(uint32_t aVideoKeyFrameInterval);
* Sets mGraphTrack if not already set, using a new stream from aTrack's
* graph.
void EnsureGraphTrackFrom(MediaTrack* aTrack);
* Takes a regular runnable and dispatches it to the graph wrapped in a
* ControlMessage.
void RunOnGraph(already_AddRefed<Runnable> aRunnable);
* Shuts down the MediaEncoder and cleans up track encoders.
* Listeners will be notified of the shutdown unless we were Cancel()ed first.
RefPtr<GenericNonExclusivePromise::AllPromiseType> Shutdown();
* Sets mError to true, notifies listeners of the error if mError changed,
* and stops encoding.
void SetError();
const RefPtr<TaskQueue> mEncoderThread;
const RefPtr<DriftCompensator> mDriftCompensator;
UniquePtr<Muxer> mMuxer;
RefPtr<AudioTrackEncoder> mAudioEncoder;
RefPtr<AudioTrackListener> mAudioListener;
RefPtr<VideoTrackEncoder> mVideoEncoder;
RefPtr<VideoTrackListener> mVideoListener;
RefPtr<EncoderListener> mEncoderListener;
nsTArray<RefPtr<MediaEncoderListener>> mListeners;
// The AudioNode we are encoding.
// Will be null when input is media stream or destination node.
RefPtr<dom::AudioNode> mAudioNode;
// Pipe-track for allowing a track listener on a non-destination AudioNode.
// Will be null when input is media stream or destination node.
RefPtr<AudioNodeTrack> mPipeTrack;
// Input port that connect mAudioNode to mPipeTrack.
// Will be null when input is media stream or destination node.
RefPtr<MediaInputPort> mInputPort;
// An audio track that we are encoding. Will be null if the input stream
// doesn't contain audio on start() or if the input is an AudioNode.
RefPtr<dom::AudioStreamTrack> mAudioTrack;
// A video track that we are encoding. Will be null if the input stream
// doesn't contain video on start() or if the input is an AudioNode.
RefPtr<dom::VideoStreamTrack> mVideoTrack;
// A stream to keep the MediaTrackGraph alive while we're recording.
RefPtr<SharedDummyTrack> mGraphTrack;
TimeStamp mStartTime;
const nsString mMIMEType;
bool mInitialized;
bool mCompleted;
bool mError;
// Set when shutdown starts.
RefPtr<GenericNonExclusivePromise::AllPromiseType> mShutdownPromise;
// Get duration from create encoder, for logging purpose
double GetEncodeTimeStamp() {
TimeDuration decodeTime;
decodeTime = TimeStamp::Now() - mStartTime;
return decodeTime.ToMilliseconds();
} // namespace mozilla