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/*! @license | ||
* Shaka Player | ||
* Copyright 2016 Google LLC | ||
* SPDX-License-Identifier: Apache-2.0 | ||
*/ | ||
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goog.provide('shaka.transmuxer.Ec3'); | ||
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goog.require('shaka.util.ExpGolomb'); | ||
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/** | ||
* EC3 utils | ||
*/ | ||
shaka.transmuxer.Ec3 = class { | ||
/** | ||
* @param {!Uint8Array} data | ||
* @param {!number} offset | ||
* @return {?{sampleRate: number, channelCount: number, | ||
* audioConfig: !Uint8Array, frameLength: number}} | ||
*/ | ||
static parseFrame(data, offset) { | ||
if (offset + 8 > data.length) { | ||
// not enough bytes left | ||
return null; | ||
} | ||
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if (!shaka.transmuxer.Ec3.probe(data, offset)) { | ||
return null; | ||
} | ||
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const gb = new shaka.util.ExpGolomb(data.subarray(offset + 2)); | ||
// Skip stream_type | ||
gb.skipBits(2); | ||
// Skip sub_stream_id | ||
gb.skipBits(3); | ||
const frameLength = (gb.readBits(11) + 1) << 1; | ||
let samplingRateCode = gb.readBits(2); | ||
let sampleRate = null; | ||
let numBlocksCode = null; | ||
if (samplingRateCode == 0x03) { | ||
samplingRateCode = gb.readBits(2); | ||
sampleRate = [24000, 22060, 16000][samplingRateCode]; | ||
numBlocksCode = 3; | ||
} else { | ||
sampleRate = [48000, 44100, 32000][samplingRateCode]; | ||
numBlocksCode = gb.readBits(2); | ||
} | ||
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const channelMode = gb.readBits(3); | ||
const lowFrequencyEffectsChannelOn = gb.readBits(1); | ||
const bitStreamIdentification = gb.readBits(5); | ||
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if (offset + frameLength > data.byteLength) { | ||
return null; | ||
} | ||
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const channelsMap = [2, 1, 2, 3, 3, 4, 4, 5]; | ||
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const numBlocksMap = [1, 2, 3, 6]; | ||
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const numBlocks = numBlocksMap[numBlocksCode]; | ||
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const dataRateSub = | ||
Math.floor((frameLength * sampleRate) / (numBlocks * 16)); | ||
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const config = new Uint8Array([ | ||
((dataRateSub & 0x1FE0) >> 5), | ||
((dataRateSub & 0x001F) << 3), // num_ind_sub = zero | ||
(sampleRate << 6) | (bitStreamIdentification << 1) | (0 << 0), | ||
(0 << 7) | (0 << 4) | | ||
(channelMode << 1) | (lowFrequencyEffectsChannelOn << 0), | ||
(0 << 5) | (0 << 1) | (0 << 0), | ||
]); | ||
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return { | ||
sampleRate: sampleRate, | ||
channelCount: channelsMap[channelMode] + lowFrequencyEffectsChannelOn, | ||
audioConfig: config, | ||
frameLength: frameLength, | ||
}; | ||
} | ||
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/** | ||
* @param {!Uint8Array} data | ||
* @param {!number} offset | ||
* @return {boolean} | ||
*/ | ||
static probe(data, offset) { | ||
// search 16-bit 0x0B77 syncword | ||
const syncword = (data[offset] << 8) | (data[offset + 1] << 0); | ||
if (syncword === 0x0B77) { | ||
return true; | ||
} else { | ||
return false; | ||
} | ||
} | ||
}; | ||
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/** | ||
* @const {number} | ||
*/ | ||
shaka.transmuxer.Ec3.EC3_SAMPLES_PER_FRAME = 1536; |
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/*! @license | ||
* Shaka Player | ||
* Copyright 2016 Google LLC | ||
* SPDX-License-Identifier: Apache-2.0 | ||
*/ | ||
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goog.provide('shaka.transmuxer.Ec3Transmuxer'); | ||
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goog.require('shaka.media.Capabilities'); | ||
goog.require('shaka.transmuxer.Ec3'); | ||
goog.require('shaka.transmuxer.TransmuxerEngine'); | ||
goog.require('shaka.util.BufferUtils'); | ||
goog.require('shaka.util.Error'); | ||
goog.require('shaka.util.Id3Utils'); | ||
goog.require('shaka.util.ManifestParserUtils'); | ||
goog.require('shaka.util.Mp4Generator'); | ||
goog.require('shaka.util.Uint8ArrayUtils'); | ||
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/** | ||
* @implements {shaka.extern.Transmuxer} | ||
* @export | ||
*/ | ||
shaka.transmuxer.Ec3Transmuxer = class { | ||
/** | ||
* @param {string} mimeType | ||
*/ | ||
constructor(mimeType) { | ||
/** @private {string} */ | ||
this.originalMimeType_ = mimeType; | ||
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/** @private {number} */ | ||
this.frameIndex_ = 0; | ||
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/** @private {!Map.<number, !Uint8Array>} */ | ||
this.initSegments = new Map(); | ||
} | ||
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/** | ||
* @override | ||
* @export | ||
*/ | ||
destroy() { | ||
this.initSegments.clear(); | ||
} | ||
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/** | ||
* Check if the mime type and the content type is supported. | ||
* @param {string} mimeType | ||
* @param {string=} contentType | ||
* @return {boolean} | ||
* @override | ||
* @export | ||
*/ | ||
isSupported(mimeType, contentType) { | ||
const Capabilities = shaka.media.Capabilities; | ||
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if (!this.isEc3Container_(mimeType)) { | ||
return false; | ||
} | ||
const ContentType = shaka.util.ManifestParserUtils.ContentType; | ||
return Capabilities.isTypeSupported( | ||
this.convertCodecs(ContentType.AUDIO, mimeType)); | ||
} | ||
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/** | ||
* Check if the mimetype is 'audio/ec3'. | ||
* @param {string} mimeType | ||
* @return {boolean} | ||
* @private | ||
*/ | ||
isEc3Container_(mimeType) { | ||
return mimeType.toLowerCase().split(';')[0] == 'audio/ec3'; | ||
} | ||
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/** | ||
* @override | ||
* @export | ||
*/ | ||
convertCodecs(contentType, mimeType) { | ||
if (this.isEc3Container_(mimeType)) { | ||
return 'audio/mp4; codecs="ec-3"'; | ||
} | ||
return mimeType; | ||
} | ||
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/** | ||
* @override | ||
* @export | ||
*/ | ||
getOrginalMimeType() { | ||
return this.originalMimeType_; | ||
} | ||
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/** | ||
* @override | ||
* @export | ||
*/ | ||
transmux(data, stream, reference, duration) { | ||
const Ec3 = shaka.transmuxer.Ec3; | ||
const Uint8ArrayUtils = shaka.util.Uint8ArrayUtils; | ||
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const uint8ArrayData = shaka.util.BufferUtils.toUint8(data); | ||
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const id3Data = shaka.util.Id3Utils.getID3Data(uint8ArrayData); | ||
let offset = id3Data.length; | ||
for (; offset < uint8ArrayData.length; offset++) { | ||
if (Ec3.probe(uint8ArrayData, offset)) { | ||
break; | ||
} | ||
} | ||
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let timestamp = reference.endTime * 1000; | ||
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const frames = shaka.util.Id3Utils.getID3Frames(id3Data); | ||
if (frames.length && reference) { | ||
const metadataTimestamp = frames.find((frame) => { | ||
return frame.description === | ||
'com.apple.streaming.transportStreamTimestamp'; | ||
}); | ||
if (metadataTimestamp) { | ||
timestamp = /** @type {!number} */(metadataTimestamp.data); | ||
} | ||
} | ||
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/** @type {number} */ | ||
let sampleRate = 0; | ||
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/** @type {!Uint8Array} */ | ||
let audioConfig = new Uint8Array([]); | ||
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/** @type {!Array.<shaka.util.Mp4Generator.Mp4Sample>} */ | ||
const samples = []; | ||
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while (offset < uint8ArrayData.length) { | ||
const frame = Ec3.parseFrame(uint8ArrayData, offset); | ||
if (!frame) { | ||
return Promise.reject(new shaka.util.Error( | ||
shaka.util.Error.Severity.CRITICAL, | ||
shaka.util.Error.Category.MEDIA, | ||
shaka.util.Error.Code.TRANSMUXING_FAILED)); | ||
} | ||
stream.audioSamplingRate = frame.sampleRate; | ||
stream.channelsCount = frame.channelCount; | ||
sampleRate = frame.sampleRate; | ||
audioConfig = frame.audioConfig; | ||
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const frameData = uint8ArrayData.subarray( | ||
offset, offset + frame.frameLength); | ||
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samples.push({ | ||
data: frameData, | ||
size: frame.frameLength, | ||
duration: Ec3.EC3_SAMPLES_PER_FRAME, | ||
cts: 0, | ||
flags: { | ||
isLeading: 0, | ||
isDependedOn: 0, | ||
hasRedundancy: 0, | ||
degradPrio: 0, | ||
dependsOn: 2, | ||
isNonSync: 0, | ||
}, | ||
}); | ||
offset += frame.frameLength; | ||
} | ||
/** @type {number} */ | ||
const baseMediaDecodeTime = Math.floor(timestamp * sampleRate / 1000); | ||
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/** @type {shaka.util.Mp4Generator.StreamInfo} */ | ||
const streamInfo = { | ||
timescale: sampleRate, | ||
duration: duration, | ||
videoNalus: [], | ||
audioConfig: audioConfig, | ||
data: { | ||
sequenceNumber: this.frameIndex_, | ||
baseMediaDecodeTime: baseMediaDecodeTime, | ||
samples: samples, | ||
}, | ||
stream: stream, | ||
}; | ||
const mp4Generator = new shaka.util.Mp4Generator(streamInfo); | ||
let initSegment; | ||
if (!this.initSegments.has(stream.id)) { | ||
initSegment = mp4Generator.initSegment(); | ||
this.initSegments.set(stream.id, initSegment); | ||
} else { | ||
initSegment = this.initSegments.get(stream.id); | ||
} | ||
const segmentData = mp4Generator.segmentData(); | ||
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this.frameIndex_++; | ||
const transmuxData = Uint8ArrayUtils.concat(initSegment, segmentData); | ||
return Promise.resolve(transmuxData); | ||
} | ||
}; | ||
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shaka.transmuxer.TransmuxerEngine.registerTransmuxer( | ||
'audio/ec3', | ||
() => new shaka.transmuxer.Ec3Transmuxer('audio/ec3'), | ||
shaka.transmuxer.TransmuxerEngine.PluginPriority.FALLBACK); |
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