shaka-player
Version:
DASH/EME video player library
220 lines (181 loc) • 6.4 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.media.Transmuxer');
goog.require('goog.asserts');
goog.require('shaka.util.BufferUtils');
goog.require('shaka.util.Error');
goog.require('shaka.util.IDestroyable');
goog.require('shaka.util.ManifestParserUtils');
goog.require('shaka.util.PublicPromise');
goog.require('shaka.util.Uint8ArrayUtils');
goog.require('shaka.dependencies');
/**
* Transmuxer provides all operations for transmuxing from Transport
* Stream to MP4.
*
* @implements {shaka.util.IDestroyable}
*/
shaka.media.Transmuxer = class {
/** */
constructor() {
/** @private {?muxjs} */
this.muxjs_ = shaka.dependencies.muxjs();
/** @private {muxjs.mp4.Transmuxer} */
this.muxTransmuxer_ = new this.muxjs_.mp4.Transmuxer({
'keepOriginalTimestamps': true,
});
/** @private {shaka.util.PublicPromise} */
this.transmuxPromise_ = null;
/** @private {!Array.<!Uint8Array>} */
this.transmuxedData_ = [];
/** @private {!Array.<muxjs.mp4.ClosedCaption>} */
this.captions_ = [];
/** @private {!Array.<muxjs.mp4.Metadata>} */
this.metadata_ = [];
/** @private {boolean} */
this.isTransmuxing_ = false;
this.muxTransmuxer_.on('data', (segment) => this.onTransmuxed_(segment));
this.muxTransmuxer_.on('done', () => this.onTransmuxDone_());
}
/**
* @override
*/
destroy() {
this.muxTransmuxer_.dispose();
this.muxTransmuxer_ = null;
return Promise.resolve();
}
/**
* Check if the content type is Transport Stream, and if muxjs is loaded.
* @param {string} mimeType
* @param {string=} contentType
* @return {boolean}
*/
static isSupported(mimeType, contentType) {
const Transmuxer = shaka.media.Transmuxer;
if (!shaka.dependencies.muxjs() || !Transmuxer.isTsContainer(mimeType)) {
return false;
}
if (contentType) {
return MediaSource.isTypeSupported(
Transmuxer.convertTsCodecs(contentType, mimeType));
}
const ContentType = shaka.util.ManifestParserUtils.ContentType;
const audioMime = Transmuxer.convertTsCodecs(ContentType.AUDIO, mimeType);
const videoMime = Transmuxer.convertTsCodecs(ContentType.VIDEO, mimeType);
return MediaSource.isTypeSupported(audioMime) ||
MediaSource.isTypeSupported(videoMime);
}
/**
* Check if the mimetype contains 'mp2t'.
* @param {string} mimeType
* @return {boolean}
*/
static isTsContainer(mimeType) {
return mimeType.toLowerCase().split(';')[0].split('/')[1] == 'mp2t';
}
/**
* For transport stream, convert its codecs to MP4 codecs.
* @param {string} contentType
* @param {string} tsMimeType
* @return {string}
*/
static convertTsCodecs(contentType, tsMimeType) {
const ContentType = shaka.util.ManifestParserUtils.ContentType;
let mp4MimeType = tsMimeType.replace(/mp2t/i, 'mp4');
if (contentType == ContentType.AUDIO) {
mp4MimeType = mp4MimeType.replace('video', 'audio');
}
// Handle legacy AVC1 codec strings (pre-RFC 6381).
// Look for "avc1.<profile>.<level>", where profile is:
// 66 (baseline => 0x42)
// 77 (main => 0x4d)
// 100 (high => 0x64)
// Reference: https://bit.ly/2K9JI3x
const match = /avc1\.(66|77|100)\.(\d+)/.exec(mp4MimeType);
if (match) {
let newCodecString = 'avc1.';
const profile = match[1];
if (profile == '66') {
newCodecString += '4200';
} else if (profile == '77') {
newCodecString += '4d00';
} else {
goog.asserts.assert(profile == '100',
'Legacy avc1 parsing code out of sync with regex!');
newCodecString += '6400';
}
// Convert the level to hex and append to the codec string.
const level = Number(match[2]);
goog.asserts.assert(level < 256,
'Invalid legacy avc1 level number!');
newCodecString += (level >> 4).toString(16);
newCodecString += (level & 0xf).toString(16);
mp4MimeType = mp4MimeType.replace(match[0], newCodecString);
}
return mp4MimeType;
}
/**
* Transmux from Transport stream to MP4, using the mux.js library.
* @param {BufferSource} data
* @return {!Promise.<{data: !Uint8Array,
* captions: !Array.<!muxjs.mp4.ClosedCaption>,
* metadata: !Array.<!Object>}>}
*/
transmux(data) {
goog.asserts.assert(!this.isTransmuxing_,
'No transmuxing should be in progress.');
this.isTransmuxing_ = true;
this.transmuxPromise_ = new shaka.util.PublicPromise();
this.transmuxedData_ = [];
this.captions_ = [];
this.metadata_ = [];
const dataArray = shaka.util.BufferUtils.toUint8(data);
this.muxTransmuxer_.push(dataArray);
this.muxTransmuxer_.flush();
// Workaround for https://bit.ly/Shaka1449 mux.js not
// emitting 'data' and 'done' events.
// mux.js code is synchronous, so if onTransmuxDone_ has
// not been called by now, it's not going to be.
// Treat it as a transmuxing failure and reject the promise.
if (this.isTransmuxing_) {
this.transmuxPromise_.reject(new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.MEDIA,
shaka.util.Error.Code.TRANSMUXING_FAILED));
}
return this.transmuxPromise_;
}
/**
* Handles the 'data' event of the transmuxer.
* Extracts the cues from the transmuxed segment, and adds them to an array.
* Stores the transmuxed data in another array, to pass it back to
* MediaSourceEngine, and append to the source buffer.
*
* @param {muxjs.mp4.Transmuxer.Segment} segment
* @private
*/
onTransmuxed_(segment) {
this.captions_ = segment.captions;
this.metadata_ = segment.metadata;
this.transmuxedData_.push(
shaka.util.Uint8ArrayUtils.concat(segment.initSegment, segment.data));
}
/**
* Handles the 'done' event of the transmuxer.
* Resolves the transmux Promise, and returns the transmuxed data.
* @private
*/
onTransmuxDone_() {
const output = {
data: shaka.util.Uint8ArrayUtils.concat(...this.transmuxedData_),
captions: this.captions_,
metadata: this.metadata_,
};
this.transmuxPromise_.resolve(output);
this.isTransmuxing_ = false;
}
};