88 lines
2.6 KiB
JavaScript
88 lines
2.6 KiB
JavaScript
const { parseTrun } = require("../tools/mp4-inspector");
|
|
const { findBox } = require("./probe");
|
|
var window = require('global/window');
|
|
|
|
/**
|
|
* Utility function for parsing data from mdat boxes.
|
|
* @param {Array<Uint8Array>} segment the segment data to create mdat/traf pairs from.
|
|
* @returns mdat and traf boxes paired up for easier parsing.
|
|
*/
|
|
var getMdatTrafPairs = function(segment) {
|
|
var trafs = findBox(segment, ['moof', 'traf']);
|
|
var mdats = findBox(segment, ['mdat']);
|
|
|
|
var mdatTrafPairs = [];
|
|
|
|
// Pair up each traf with a mdat as moofs and mdats are in pairs
|
|
mdats.forEach(function(mdat, index) {
|
|
var matchingTraf = trafs[index];
|
|
mdatTrafPairs.push({
|
|
mdat: mdat,
|
|
traf: matchingTraf
|
|
});
|
|
});
|
|
|
|
return mdatTrafPairs;
|
|
};
|
|
|
|
/**
|
|
* Parses sample information out of Track Run Boxes and calculates
|
|
* the absolute presentation and decode timestamps of each sample.
|
|
*
|
|
* @param {Array<Uint8Array>} truns - The Trun Run boxes to be parsed
|
|
* @param {Number|BigInt} baseMediaDecodeTime - base media decode time from tfdt
|
|
@see ISO-BMFF-12/2015, Section 8.8.12
|
|
* @param {Object} tfhd - The parsed Track Fragment Header
|
|
* @see inspect.parseTfhd
|
|
* @return {Object[]} the parsed samples
|
|
*
|
|
* @see ISO-BMFF-12/2015, Section 8.8.8
|
|
**/
|
|
var parseSamples = function(truns, baseMediaDecodeTime, tfhd) {
|
|
var currentDts = baseMediaDecodeTime;
|
|
var defaultSampleDuration = tfhd.defaultSampleDuration || 0;
|
|
var defaultSampleSize = tfhd.defaultSampleSize || 0;
|
|
var trackId = tfhd.trackId;
|
|
var allSamples = [];
|
|
|
|
truns.forEach(function(trun) {
|
|
// Note: We currently do not parse the sample table as well
|
|
// as the trun. It's possible some sources will require this.
|
|
// moov > trak > mdia > minf > stbl
|
|
var trackRun = parseTrun(trun);
|
|
var samples = trackRun.samples;
|
|
|
|
samples.forEach(function(sample) {
|
|
if (sample.duration === undefined) {
|
|
sample.duration = defaultSampleDuration;
|
|
}
|
|
if (sample.size === undefined) {
|
|
sample.size = defaultSampleSize;
|
|
}
|
|
sample.trackId = trackId;
|
|
sample.dts = currentDts;
|
|
if (sample.compositionTimeOffset === undefined) {
|
|
sample.compositionTimeOffset = 0;
|
|
}
|
|
|
|
if (typeof currentDts === 'bigint') {
|
|
sample.pts = currentDts + window.BigInt(sample.compositionTimeOffset);
|
|
currentDts += window.BigInt(sample.duration);
|
|
|
|
} else {
|
|
sample.pts = currentDts + sample.compositionTimeOffset;
|
|
currentDts += sample.duration;
|
|
}
|
|
});
|
|
|
|
allSamples = allSamples.concat(samples);
|
|
});
|
|
|
|
return allSamples;
|
|
};
|
|
|
|
module.exports = {
|
|
getMdatTrafPairs,
|
|
parseSamples
|
|
};
|