| ContainerWriter.h |
ContainerWriter packs encoded track data into a specific media container.
|
2619 |
| EncodedFrame.h |
|
2206 |
| MediaEncoder.cpp |
|
37460 |
| MediaEncoder.h |
MediaEncoder is the framework of encoding module, it controls and manages
procedures between Muxer, ContainerWriter and TrackEncoder. ContainerWriter
writes the encoded track data into a specific container (e.g. ogg, webm).
AudioTrackEncoder and VideoTrackEncoder are subclasses of TrackEncoder, and
are responsible for encoding raw data coming from MediaStreamTracks.
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 MediaEncoder automatically encodes incoming data, muxes it, writes it
into a container and stores the container data into a MutableBlobStorage.
It is timeslice-aware so that it can notify listeners when it's time to
expose a blob due to filling the timeslice.
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. Note that there are more
configuration options, see the docs on MediaEncoder::CreateEncoder.
=> encoder = MediaEncoder::CreateEncoder(aMIMEType);
It then creates track encoders and the appropriate ContainerWriter
according to the MIME type
2) Connect handlers through MediaEventListeners to the MediaEncoder's
MediaEventSources, StartedEvent(), DataAvailableEvent(), ErrorEvent() and
ShutdownEvent().
=> listener = encoder->DataAvailableEvent().Connect(mainThread, &OnBlob);
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) MediaEncoder automatically encodes data from the connected tracks, muxes
them and writes it all into a blob, including metadata. When the blob
contains at least `timeslice` worth of data it notifies the
DataAvailableEvent that was connected in step 2.
=> void OnBlob(RefPtr<BlobImpl> aBlob) {
=> DispatchBlobEvent(Blob::Create(GetOwnerGlobal(), aBlob));
=> };
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.
|
14550 |
| moz.build |
|
1159 |
| Muxer.cpp |
|
6568 |
| Muxer.h |
|
2583 |
| OpusTrackEncoder.cpp |
|
16400 |
| OpusTrackEncoder.h |
The encoder lookahead at 48k rate.
|
3215 |
| TrackEncoder.cpp |
|
26561 |
| TrackEncoder.h |
Called when the TrackEncoder has received its first real data.
|
15231 |
| TrackMetadataBase.h |
|
2495 |
| VP8TrackEncoder.cpp |
std::min(10U, mKeyFrameInterval / 200) |
25141 |
| VP8TrackEncoder.h |
VP8TrackEncoder implements VideoTrackEncoder by using the libvpx library.
We implement a realtime and variable frame rate encoder. In order to achieve
that, there is a frame-drop encoding policy implemented in Encode().
|
5794 |