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- "use strict";
- /**
- * mux.js
- *
- * Copyright (c) Brightcove
- * Licensed Apache-2.0 https://github.com/videojs/mux.js/blob/master/LICENSE
- */
- var highPrefix = [33, 16, 5, 32, 164, 27];
- var lowPrefix = [33, 65, 108, 84, 1, 2, 4, 8, 168, 2, 4, 8, 17, 191, 252];
- var zeroFill = function zeroFill(count) {
- var a = [];
- while (count--) {
- a.push(0);
- }
- return a;
- };
- var makeTable = function makeTable(metaTable) {
- return Object.keys(metaTable).reduce(function (obj, key) {
- obj[key] = new Uint8Array(metaTable[key].reduce(function (arr, part) {
- return arr.concat(part);
- }, []));
- return obj;
- }, {});
- };
- var silence;
- module.exports = function () {
- if (!silence) {
- // Frames-of-silence to use for filling in missing AAC frames
- var coneOfSilence = {
- 96000: [highPrefix, [227, 64], zeroFill(154), [56]],
- 88200: [highPrefix, [231], zeroFill(170), [56]],
- 64000: [highPrefix, [248, 192], zeroFill(240), [56]],
- 48000: [highPrefix, [255, 192], zeroFill(268), [55, 148, 128], zeroFill(54), [112]],
- 44100: [highPrefix, [255, 192], zeroFill(268), [55, 163, 128], zeroFill(84), [112]],
- 32000: [highPrefix, [255, 192], zeroFill(268), [55, 234], zeroFill(226), [112]],
- 24000: [highPrefix, [255, 192], zeroFill(268), [55, 255, 128], zeroFill(268), [111, 112], zeroFill(126), [224]],
- 16000: [highPrefix, [255, 192], zeroFill(268), [55, 255, 128], zeroFill(268), [111, 255], zeroFill(269), [223, 108], zeroFill(195), [1, 192]],
- 12000: [lowPrefix, zeroFill(268), [3, 127, 248], zeroFill(268), [6, 255, 240], zeroFill(268), [13, 255, 224], zeroFill(268), [27, 253, 128], zeroFill(259), [56]],
- 11025: [lowPrefix, zeroFill(268), [3, 127, 248], zeroFill(268), [6, 255, 240], zeroFill(268), [13, 255, 224], zeroFill(268), [27, 255, 192], zeroFill(268), [55, 175, 128], zeroFill(108), [112]],
- 8000: [lowPrefix, zeroFill(268), [3, 121, 16], zeroFill(47), [7]]
- };
- silence = makeTable(coneOfSilence);
- }
- return silence;
- };
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