First release

node_modules/mux.js/lib/flv/coalesce-stream.js

@@ -0,0 +1,151 @@
+/**
+ * mux.js
+ *
+ * Copyright (c) Brightcove
+ * Licensed Apache-2.0 https://github.com/videojs/mux.js/blob/master/LICENSE
+ */
+'use strict';
+
+var Stream = require('../utils/stream.js');
+
+/**
+ * The final stage of the transmuxer that emits the flv tags
+ * for audio, video, and metadata. Also tranlates in time and
+ * outputs caption data and id3 cues.
+ */
+var CoalesceStream = function(options) {
+  // Number of Tracks per output segment
+  // If greater than 1, we combine multiple
+  // tracks into a single segment
+  this.numberOfTracks = 0;
+  this.metadataStream = options.metadataStream;
+
+  this.videoTags = [];
+  this.audioTags = [];
+  this.videoTrack = null;
+  this.audioTrack = null;
+  this.pendingCaptions = [];
+  this.pendingMetadata = [];
+  this.pendingTracks = 0;
+  this.processedTracks = 0;
+
+  CoalesceStream.prototype.init.call(this);
+
+  // Take output from multiple
+  this.push = function(output) {
+    // buffer incoming captions until the associated video segment
+    // finishes
+    if (output.text) {
+      return this.pendingCaptions.push(output);
+    }
+    // buffer incoming id3 tags until the final flush
+    if (output.frames) {
+      return this.pendingMetadata.push(output);
+    }
+
+    if (output.track.type === 'video') {
+      this.videoTrack = output.track;
+      this.videoTags = output.tags;
+      this.pendingTracks++;
+    }
+    if (output.track.type === 'audio') {
+      this.audioTrack = output.track;
+      this.audioTags = output.tags;
+      this.pendingTracks++;
+    }
+  };
+};
+
+CoalesceStream.prototype = new Stream();
+CoalesceStream.prototype.flush = function(flushSource) {
+  var
+    id3,
+    caption,
+    i,
+    timelineStartPts,
+    event = {
+      tags: {},
+      captions: [],
+      captionStreams: {},
+      metadata: []
+    };
+
+  if (this.pendingTracks < this.numberOfTracks) {
+    if (flushSource !== 'VideoSegmentStream' &&
+        flushSource !== 'AudioSegmentStream') {
+      // Return because we haven't received a flush from a data-generating
+      // portion of the segment (meaning that we have only recieved meta-data
+      // or captions.)
+      return;
+    } else if (this.pendingTracks === 0) {
+      // In the case where we receive a flush without any data having been
+      // received we consider it an emitted track for the purposes of coalescing
+      // `done` events.
+      // We do this for the case where there is an audio and video track in the
+      // segment but no audio data. (seen in several playlists with alternate
+      // audio tracks and no audio present in the main TS segments.)
+      this.processedTracks++;
+
+      if (this.processedTracks < this.numberOfTracks) {
+        return;
+      }
+    }
+  }
+
+  this.processedTracks += this.pendingTracks;
+  this.pendingTracks = 0;
+
+  if (this.processedTracks < this.numberOfTracks) {
+    return;
+  }
+
+  if (this.videoTrack) {
+    timelineStartPts = this.videoTrack.timelineStartInfo.pts;
+  } else if (this.audioTrack) {
+    timelineStartPts = this.audioTrack.timelineStartInfo.pts;
+  }
+
+  event.tags.videoTags = this.videoTags;
+  event.tags.audioTags = this.audioTags;
+
+  // Translate caption PTS times into second offsets into the
+  // video timeline for the segment, and add track info
+  for (i = 0; i < this.pendingCaptions.length; i++) {
+    caption = this.pendingCaptions[i];
+    caption.startTime = caption.startPts - timelineStartPts;
+    caption.startTime /= 90e3;
+    caption.endTime = caption.endPts - timelineStartPts;
+    caption.endTime /= 90e3;
+    event.captionStreams[caption.stream] = true;
+    event.captions.push(caption);
+  }
+
+  // Translate ID3 frame PTS times into second offsets into the
+  // video timeline for the segment
+  for (i = 0; i < this.pendingMetadata.length; i++) {
+    id3 = this.pendingMetadata[i];
+    id3.cueTime = id3.pts - timelineStartPts;
+    id3.cueTime /= 90e3;
+    event.metadata.push(id3);
+  }
+  // We add this to every single emitted segment even though we only need
+  // it for the first
+  event.metadata.dispatchType = this.metadataStream.dispatchType;
+
+  // Reset stream state
+  this.videoTrack = null;
+  this.audioTrack = null;
+  this.videoTags = [];
+  this.audioTags = [];
+  this.pendingCaptions.length = 0;
+  this.pendingMetadata.length = 0;
+  this.pendingTracks = 0;
+  this.processedTracks = 0;
+
+  // Emit the final segment
+  this.trigger('data', event);
+
+  this.trigger('done');
+};
+
+module.exports = CoalesceStream;