First release

node_modules/mux.js/cjs/partial/audio-segment-stream.js

@@ -0,0 +1,141 @@
+'use strict';
+
+var Stream = require('../utils/stream.js');
+
+var mp4 = require('../mp4/mp4-generator.js');
+
+var audioFrameUtils = require('../mp4/audio-frame-utils');
+
+var trackInfo = require('../mp4/track-decode-info.js');
+
+var ONE_SECOND_IN_TS = require('../utils/clock').ONE_SECOND_IN_TS;
+
+var AUDIO_PROPERTIES = require('../constants/audio-properties.js');
+/**
+ * Constructs a single-track, ISO BMFF media segment from AAC data
+ * events. The output of this stream can be fed to a SourceBuffer
+ * configured with a suitable initialization segment.
+ */
+
+
+var AudioSegmentStream = function AudioSegmentStream(track, options) {
+  var adtsFrames = [],
+      sequenceNumber = 0,
+      earliestAllowedDts = 0,
+      audioAppendStartTs = 0,
+      videoBaseMediaDecodeTime = Infinity,
+      segmentStartPts = null,
+      segmentEndPts = null;
+  options = options || {};
+  AudioSegmentStream.prototype.init.call(this);
+
+  this.push = function (data) {
+    trackInfo.collectDtsInfo(track, data);
+
+    if (track) {
+      AUDIO_PROPERTIES.forEach(function (prop) {
+        track[prop] = data[prop];
+      });
+    } // buffer audio data until end() is called
+
+
+    adtsFrames.push(data);
+  };
+
+  this.setEarliestDts = function (earliestDts) {
+    earliestAllowedDts = earliestDts;
+  };
+
+  this.setVideoBaseMediaDecodeTime = function (baseMediaDecodeTime) {
+    videoBaseMediaDecodeTime = baseMediaDecodeTime;
+  };
+
+  this.setAudioAppendStart = function (timestamp) {
+    audioAppendStartTs = timestamp;
+  };
+
+  this.processFrames_ = function () {
+    var frames, moof, mdat, boxes, timingInfo; // return early if no audio data has been observed
+
+    if (adtsFrames.length === 0) {
+      return;
+    }
+
+    frames = audioFrameUtils.trimAdtsFramesByEarliestDts(adtsFrames, track, earliestAllowedDts);
+
+    if (frames.length === 0) {
+      // return early if the frames are all after the earliest allowed DTS
+      // TODO should we clear the adtsFrames?
+      return;
+    }
+
+    track.baseMediaDecodeTime = trackInfo.calculateTrackBaseMediaDecodeTime(track, options.keepOriginalTimestamps);
+    audioFrameUtils.prefixWithSilence(track, frames, audioAppendStartTs, videoBaseMediaDecodeTime); // we have to build the index from byte locations to
+    // samples (that is, adts frames) in the audio data
+
+    track.samples = audioFrameUtils.generateSampleTable(frames); // concatenate the audio data to constuct the mdat
+
+    mdat = mp4.mdat(audioFrameUtils.concatenateFrameData(frames));
+    adtsFrames = [];
+    moof = mp4.moof(sequenceNumber, [track]); // bump the sequence number for next time
+
+    sequenceNumber++;
+    track.initSegment = mp4.initSegment([track]); // it would be great to allocate this array up front instead of
+    // throwing away hundreds of media segment fragments
+
+    boxes = new Uint8Array(moof.byteLength + mdat.byteLength);
+    boxes.set(moof);
+    boxes.set(mdat, moof.byteLength);
+    trackInfo.clearDtsInfo(track);
+
+    if (segmentStartPts === null) {
+      segmentEndPts = segmentStartPts = frames[0].pts;
+    }
+
+    segmentEndPts += frames.length * (ONE_SECOND_IN_TS * 1024 / track.samplerate);
+    timingInfo = {
+      start: segmentStartPts
+    };
+    this.trigger('timingInfo', timingInfo);
+    this.trigger('data', {
+      track: track,
+      boxes: boxes
+    });
+  };
+
+  this.flush = function () {
+    this.processFrames_(); // trigger final timing info
+
+    this.trigger('timingInfo', {
+      start: segmentStartPts,
+      end: segmentEndPts
+    });
+    this.resetTiming_();
+    this.trigger('done', 'AudioSegmentStream');
+  };
+
+  this.partialFlush = function () {
+    this.processFrames_();
+    this.trigger('partialdone', 'AudioSegmentStream');
+  };
+
+  this.endTimeline = function () {
+    this.flush();
+    this.trigger('endedtimeline', 'AudioSegmentStream');
+  };
+
+  this.resetTiming_ = function () {
+    trackInfo.clearDtsInfo(track);
+    segmentStartPts = null;
+    segmentEndPts = null;
+  };
+
+  this.reset = function () {
+    this.resetTiming_();
+    adtsFrames = [];
+    this.trigger('reset');
+  };
+};
+
+AudioSegmentStream.prototype = new Stream();
+module.exports = AudioSegmentStream;