134 lines
3.9 KiB
JavaScript
134 lines
3.9 KiB
JavaScript
/**
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* mux.js
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*
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* Copyright (c) Brightcove
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* Licensed Apache-2.0 https://github.com/videojs/mux.js/blob/master/LICENSE
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*/
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'use strict';
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var tagTypes = {
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0x08: 'audio',
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0x09: 'video',
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0x12: 'metadata'
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},
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hex = function hex(val) {
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return '0x' + ('00' + val.toString(16)).slice(-2).toUpperCase();
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},
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hexStringList = function hexStringList(data) {
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var arr = [],
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i;
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while (data.byteLength > 0) {
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i = 0;
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arr.push(hex(data[i++]));
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data = data.subarray(i);
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}
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return arr.join(' ');
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},
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parseAVCTag = function parseAVCTag(tag, obj) {
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var avcPacketTypes = ['AVC Sequence Header', 'AVC NALU', 'AVC End-of-Sequence'],
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compositionTime = tag[1] & parseInt('01111111', 2) << 16 | tag[2] << 8 | tag[3];
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obj = obj || {};
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obj.avcPacketType = avcPacketTypes[tag[0]];
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obj.CompositionTime = tag[1] & parseInt('10000000', 2) ? -compositionTime : compositionTime;
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if (tag[0] === 1) {
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obj.nalUnitTypeRaw = hexStringList(tag.subarray(4, 100));
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} else {
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obj.data = hexStringList(tag.subarray(4));
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}
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return obj;
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},
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parseVideoTag = function parseVideoTag(tag, obj) {
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var frameTypes = ['Unknown', 'Keyframe (for AVC, a seekable frame)', 'Inter frame (for AVC, a nonseekable frame)', 'Disposable inter frame (H.263 only)', 'Generated keyframe (reserved for server use only)', 'Video info/command frame'],
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codecID = tag[0] & parseInt('00001111', 2);
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obj = obj || {};
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obj.frameType = frameTypes[(tag[0] & parseInt('11110000', 2)) >>> 4];
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obj.codecID = codecID;
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if (codecID === 7) {
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return parseAVCTag(tag.subarray(1), obj);
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}
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return obj;
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},
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parseAACTag = function parseAACTag(tag, obj) {
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var packetTypes = ['AAC Sequence Header', 'AAC Raw'];
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obj = obj || {};
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obj.aacPacketType = packetTypes[tag[0]];
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obj.data = hexStringList(tag.subarray(1));
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return obj;
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},
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parseAudioTag = function parseAudioTag(tag, obj) {
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var formatTable = ['Linear PCM, platform endian', 'ADPCM', 'MP3', 'Linear PCM, little endian', 'Nellymoser 16-kHz mono', 'Nellymoser 8-kHz mono', 'Nellymoser', 'G.711 A-law logarithmic PCM', 'G.711 mu-law logarithmic PCM', 'reserved', 'AAC', 'Speex', 'MP3 8-Khz', 'Device-specific sound'],
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samplingRateTable = ['5.5-kHz', '11-kHz', '22-kHz', '44-kHz'],
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soundFormat = (tag[0] & parseInt('11110000', 2)) >>> 4;
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obj = obj || {};
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obj.soundFormat = formatTable[soundFormat];
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obj.soundRate = samplingRateTable[(tag[0] & parseInt('00001100', 2)) >>> 2];
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obj.soundSize = (tag[0] & parseInt('00000010', 2)) >>> 1 ? '16-bit' : '8-bit';
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obj.soundType = tag[0] & parseInt('00000001', 2) ? 'Stereo' : 'Mono';
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if (soundFormat === 10) {
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return parseAACTag(tag.subarray(1), obj);
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}
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return obj;
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},
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parseGenericTag = function parseGenericTag(tag) {
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return {
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tagType: tagTypes[tag[0]],
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dataSize: tag[1] << 16 | tag[2] << 8 | tag[3],
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timestamp: tag[7] << 24 | tag[4] << 16 | tag[5] << 8 | tag[6],
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streamID: tag[8] << 16 | tag[9] << 8 | tag[10]
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};
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},
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inspectFlvTag = function inspectFlvTag(tag) {
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var header = parseGenericTag(tag);
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switch (tag[0]) {
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case 0x08:
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parseAudioTag(tag.subarray(11), header);
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break;
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case 0x09:
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parseVideoTag(tag.subarray(11), header);
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break;
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case 0x12:
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}
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return header;
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},
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inspectFlv = function inspectFlv(bytes) {
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var i = 9,
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// header
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dataSize,
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parsedResults = [],
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tag; // traverse the tags
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i += 4; // skip previous tag size
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while (i < bytes.byteLength) {
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dataSize = bytes[i + 1] << 16;
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dataSize |= bytes[i + 2] << 8;
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dataSize |= bytes[i + 3];
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dataSize += 11;
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tag = bytes.subarray(i, i + dataSize);
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parsedResults.push(inspectFlvTag(tag));
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i += dataSize + 4;
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}
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return parsedResults;
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},
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textifyFlv = function textifyFlv(flvTagArray) {
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return JSON.stringify(flvTagArray, null, 2);
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};
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module.exports = {
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inspectTag: inspectFlvTag,
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inspect: inspectFlv,
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textify: textifyFlv
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}; |