fix: only append/request init segments when they change (#1128)

src/segment-loader.js

@@ -2096,9 +2096,8 @@ export default class SegmentLoader extends videojs.EventTarget {
  // we can re-append the init segment in the event that we get data from a new
  // playlist. Discontinuities and track changes are handled in other sections.
  this.playlistOfLastInitSegment_[type] = playlist;
- // we should only be appending the next init segment if we detect a change, or if
- // the segment has a map
- this.appendInitSegment_[type] = map ? true : false;
+ // Disable future init segment appends for this type. Until a change is necessary.
+ this.appendInitSegment_[type] = false;
 
  // we need to clear out the fmp4 active init segment id, since
  // we are appending the muxer init segment
@@ -2368,6 +2367,19 @@ export default class SegmentLoader extends videojs.EventTarget {
 
  this.logger_(`Requesting ${segmentInfoString(segmentInfo)}`);
 
+ // If there's an init segment associated with this segment, but it is not cached (identified by a lack of bytes),
+ // then this init segment has never been seen before and should be appended.
+ //
+ // At this point the content type (audio/video or both) is not yet known, but it should be safe to set
+ // both to true and leave the decision of whether to append the init segment to append time.
+ if (simpleSegment.map && !simpleSegment.map.bytes) {
+ this.logger_('going to request init segment.');
+ this.appendInitSegment_ = {
+ video: true,
+ audio: true
+ };
+ }
+
  segmentInfo.abortRequests = mediaSegmentRequest({
  xhr: this.vhs_.xhr,
  xhrOptions: this.xhrOptions_,

test/segment-loader.test.js

@@ -3079,7 +3079,7 @@ QUnit.module('SegmentLoader', function(hooks) {
  origAppendToSourceBuffer(config);
  };
 
- const playlist = playlistWithDuration(30);
+ const playlist = playlistWithDuration(40);
 
  playlist.segments[0].map = {
  resolvedUri: 'init.mp4',
@@ -3096,6 +3096,11 @@ QUnit.module('SegmentLoader', function(hooks) {
  byterange: { length: Infinity, offset: 0 }
  };
 
+ playlist.segments[3].map = {
+ resolvedUri: 'init.mp4',
+ byterange: { length: Infinity, offset: 0 }
+ };
+
  loader.playlist(playlist);
  loader.load();
  this.clock.tick(1);
@@ -3142,6 +3147,9 @@ QUnit.module('SegmentLoader', function(hooks) {
  appends[1].initSegment,
  'appended a different init segment'
  );
+ // force init segment append to prove that init segments are not
+ // re-requested, but will be re-appended when needed.
+ loader.appendInitSegment_.audio = true;
 
  // no init segment request, as it should be the same (and cached) segment
  standardXHRResponse(this.requests.shift(), mp4AudioSegment());
@@ -3150,6 +3158,7 @@ QUnit.module('SegmentLoader', function(hooks) {
  loader.one('error', reject);
  });
  }).then(() => {
+ this.clock.tick(1);
 
  assert.equal(appends.length, 3, 'one more append');
  assert.equal(appends[2].type, 'audio', 'appended to audio buffer');
@@ -3159,6 +3168,17 @@ QUnit.module('SegmentLoader', function(hooks) {
  appends[2].initSegment,
  'reused the init segment'
  );
+
+ // no init segment request, as it should be the same (and cached) segment
+ standardXHRResponse(this.requests.shift(), mp4AudioSegment());
+ return new Promise((resolve, reject) => {
+ loader.one('appended', resolve);
+ loader.one('error', reject);
+ });
+ }).then(() => {
+ assert.equal(appends.length, 4, 'one more append');
+ assert.equal(appends[3].type, 'audio', 'appended to audio buffer');
+ assert.notOk(appends[3].initSegment, 'did not append audio init segment');
  });
  });
 
@@ -3176,7 +3196,7 @@ QUnit.module('SegmentLoader', function(hooks) {
  origAppendToSourceBuffer(config);
  };
 
- const playlist = playlistWithDuration(30);
+ const playlist = playlistWithDuration(40);
 
  playlist.segments[0].map = {
  resolvedUri: 'init.mp4',
@@ -3193,6 +3213,11 @@ QUnit.module('SegmentLoader', function(hooks) {
  byterange: { length: Infinity, offset: 0 }
  };
 
+ playlist.segments[3].map = {
+ resolvedUri: 'init.mp4',
+ byterange: { length: Infinity, offset: 0 }
+ };
+
  loader.playlist(playlist);
  loader.load();
  this.clock.tick(1);
@@ -3229,13 +3254,18 @@ QUnit.module('SegmentLoader', function(hooks) {
  'appended a different init segment'
  );
 
+ // force init segment append to prove that init segments are not
+ // re-requested, but will be re-appended when needed.
+ loader.appendInitSegment_.video = true;
+
  // no init segment request, as it should be the same (and cached) segment
  standardXHRResponse(this.requests.shift(), mp4VideoSegment());
  return new Promise((resolve, reject) => {
  loader.one('appended', resolve);
  loader.one('error', reject);
  });
  }).then(() => {
+ this.clock.tick(1);
 
  assert.equal(appends.length, 3, 'one more append');
  assert.equal(appends[2].type, 'video', 'appended to video buffer');
@@ -3245,6 +3275,17 @@ QUnit.module('SegmentLoader', function(hooks) {
  appends[2].initSegment,
  'reused the init segment'
  );
+
+ // no init segment request, as it should be the same (and cached) segment
+ standardXHRResponse(this.requests.shift(), mp4VideoSegment());
+ return new Promise((resolve, reject) => {
+ loader.one('appended', resolve);
+ loader.one('error', reject);
+ });
+ }).then(() => {
+ assert.equal(appends.length, 4, 'one more append');
+ assert.equal(appends[3].type, 'video', 'appended to video buffer');
+ assert.notOk(appends[3].initSegment, 'did not append video init segment');
  });
  });