First release

node_modules/mux.js/cjs/mp4/track-decode-info.js

@@ -0,0 +1,108 @@
+"use strict";
+
+/**
+ * mux.js
+ *
+ * Copyright (c) Brightcove
+ * Licensed Apache-2.0 https://github.com/videojs/mux.js/blob/master/LICENSE
+ */
+var ONE_SECOND_IN_TS = require('../utils/clock').ONE_SECOND_IN_TS;
+/**
+ * Store information about the start and end of the track and the
+ * duration for each frame/sample we process in order to calculate
+ * the baseMediaDecodeTime
+ */
+
+
+var collectDtsInfo = function collectDtsInfo(track, data) {
+  if (typeof data.pts === 'number') {
+    if (track.timelineStartInfo.pts === undefined) {
+      track.timelineStartInfo.pts = data.pts;
+    }
+
+    if (track.minSegmentPts === undefined) {
+      track.minSegmentPts = data.pts;
+    } else {
+      track.minSegmentPts = Math.min(track.minSegmentPts, data.pts);
+    }
+
+    if (track.maxSegmentPts === undefined) {
+      track.maxSegmentPts = data.pts;
+    } else {
+      track.maxSegmentPts = Math.max(track.maxSegmentPts, data.pts);
+    }
+  }
+
+  if (typeof data.dts === 'number') {
+    if (track.timelineStartInfo.dts === undefined) {
+      track.timelineStartInfo.dts = data.dts;
+    }
+
+    if (track.minSegmentDts === undefined) {
+      track.minSegmentDts = data.dts;
+    } else {
+      track.minSegmentDts = Math.min(track.minSegmentDts, data.dts);
+    }
+
+    if (track.maxSegmentDts === undefined) {
+      track.maxSegmentDts = data.dts;
+    } else {
+      track.maxSegmentDts = Math.max(track.maxSegmentDts, data.dts);
+    }
+  }
+};
+/**
+ * Clear values used to calculate the baseMediaDecodeTime between
+ * tracks
+ */
+
+
+var clearDtsInfo = function clearDtsInfo(track) {
+  delete track.minSegmentDts;
+  delete track.maxSegmentDts;
+  delete track.minSegmentPts;
+  delete track.maxSegmentPts;
+};
+/**
+ * Calculate the track's baseMediaDecodeTime based on the earliest
+ * DTS the transmuxer has ever seen and the minimum DTS for the
+ * current track
+ * @param track {object} track metadata configuration
+ * @param keepOriginalTimestamps {boolean} If true, keep the timestamps
+ *        in the source; false to adjust the first segment to start at 0.
+ */
+
+
+var calculateTrackBaseMediaDecodeTime = function calculateTrackBaseMediaDecodeTime(track, keepOriginalTimestamps) {
+  var baseMediaDecodeTime,
+      scale,
+      minSegmentDts = track.minSegmentDts; // Optionally adjust the time so the first segment starts at zero.
+
+  if (!keepOriginalTimestamps) {
+    minSegmentDts -= track.timelineStartInfo.dts;
+  } // track.timelineStartInfo.baseMediaDecodeTime is the location, in time, where
+  // we want the start of the first segment to be placed
+
+
+  baseMediaDecodeTime = track.timelineStartInfo.baseMediaDecodeTime; // Add to that the distance this segment is from the very first
+
+  baseMediaDecodeTime += minSegmentDts; // baseMediaDecodeTime must not become negative
+
+  baseMediaDecodeTime = Math.max(0, baseMediaDecodeTime);
+
+  if (track.type === 'audio') {
+    // Audio has a different clock equal to the sampling_rate so we need to
+    // scale the PTS values into the clock rate of the track
+    scale = track.samplerate / ONE_SECOND_IN_TS;
+    baseMediaDecodeTime *= scale;
+    baseMediaDecodeTime = Math.floor(baseMediaDecodeTime);
+  }
+
+  return baseMediaDecodeTime;
+};
+
+module.exports = {
+  clearDtsInfo: clearDtsInfo,
+  calculateTrackBaseMediaDecodeTime: calculateTrackBaseMediaDecodeTime,
+  collectDtsInfo: collectDtsInfo
+};