fix(playback-watcher): ignore subtitles (#980)

It's possible that a subtitle track will have segments without any text
in them depending on how the subtitles and captions were created.
Therefor, we should ignore it in the playback-watcher where we're
checking for excessive downloads.

src/playback-watcher.js

@@ -11,7 +11,6 @@
 import window from 'global/window';
 import * as Ranges from './ranges';
 import logger from './util/logger';
-import videojs from 'video.js';
 
 // Set of events that reset the playback-watcher time check logic and clear the timeout
 const timerCancelEvents = [
@@ -220,14 +219,6 @@ export default class PlaybackWatcher {
  this.tech_.trigger({type: 'usage', name: `vhs-${type}-download-exclusion`});
 
  if (type === 'subtitle') {
- // TODO: Is there anything else that we can do here?
- // removing the track and disabling could have accesiblity implications.
- const track = loader.track();
- const label = track.label || track.language || 'Unknown';
-
- videojs.log.warn(`Text track "${label}" is not working correctly. It will be disabled and excluded.`);
- track.mode = 'disabled';
- this.tech_.textTracks().removeTrack(track);
  return;
  }
 

test/playback-watcher.test.js

@@ -933,64 +933,64 @@ QUnit.module('PlaybackWatcher download detection', {
 });
 
 loaderTypes.forEach(function(type) {
- QUnit.test(`detects ${type} appends without buffer changes and excludes`, function(assert) {
- this.setup();
- const loader = this.mpc[`${type}SegmentLoader_`];
- const track = {label: 'foobar', mode: 'showing'};
+ if (type !== 'subtitle') {
+ QUnit.test(`detects ${type} appends without buffer changes and excludes`, function(assert) {
+ this.setup();
+ const loader = this.mpc[`${type}SegmentLoader_`];
+ const track = {label: 'foobar', mode: 'showing'};
 
- if (type === 'subtitle') {
- loader.track = () => track;
- sinon.stub(this.player.tech_.textTracks(), 'removeTrack');
- }
+  if (type === 'subtitle') {
+  loader.track = () => track;
+  sinon.stub(this.player.tech_.textTracks(), 'removeTrack');
+  }
 
- this.setBuffered(videojs.createTimeRanges([[0, 30]]));
+  this.setBuffered(videojs.createTimeRanges([[0, 30]]));
 
- for (let i = 0; i <= EXCLUDE_APPEND_COUNT; i++) {
- loader.trigger('appendsdone');
- if (i === EXCLUDE_APPEND_COUNT) {
- assert.equal(this.playbackWatcher[`${type}StalledDownloads_`], 0, `append #${i} resets stalled downloads to 0`);
- } else {
- assert.equal(this.playbackWatcher[`${type}StalledDownloads_`], i, `append #${i + 1} ${i} stalled downloads`);
+ for (let i = 0; i <= EXCLUDE_APPEND_COUNT; i++) {
+ loader.trigger('appendsdone');
+ if (i === EXCLUDE_APPEND_COUNT) {
+ assert.equal(this.playbackWatcher[`${type}StalledDownloads_`], 0, `append #${i} resets stalled downloads to 0`);
+ } else {
+ assert.equal(this.playbackWatcher[`${type}StalledDownloads_`], i, `append #${i + 1} ${i} stalled downloads`);
+ }
  }
- }
 
- const expectedUsage = {};
+  const expectedUsage = {};
 
- expectedUsage[`vhs-${type}-download-exclusion`] = 1;
+  expectedUsage[`vhs-${type}-download-exclusion`] = 1;
 
- if (type !== 'subtitle') {
- expectedUsage['vhs-rendition-blacklisted'] = 1;
- expectedUsage['hls-rendition-blacklisted'] = 1;
- }
+  if (type !== 'subtitle') {
+  expectedUsage['vhs-rendition-blacklisted'] = 1;
+  expectedUsage['hls-rendition-blacklisted'] = 1;
+  }
 
- assert.deepEqual(this.usageEvents, expectedUsage, 'usage as expected');
+  assert.deepEqual(this.usageEvents, expectedUsage, 'usage as expected');
 
- if (type !== 'subtitle') {
- const message = 'Playback cannot continue. No available working or supported playlists.';
+  if (type !== 'subtitle') {
+  const message = 'Playback cannot continue. No available working or supported playlists.';
 
- assert.equal(this.mpcErrors, 1, 'one mpc error');
- assert.equal(this.mpc.error, message, 'mpc error set');
- assert.equal(this.player.error().message, message, 'player error set');
- assert.equal(this.env.log.error.callCount, 1, 'player error logged');
- assert.equal(this.env.log.error.args[0][1], message, 'error message as expected');
+  assert.equal(this.mpcErrors, 1, 'one mpc error');
+  assert.equal(this.mpc.error, message, 'mpc error set');
+  assert.equal(this.player.error().message, message, 'player error set');
+  assert.equal(this.env.log.error.callCount, 1, 'player error logged');
+  assert.equal(this.env.log.error.args[0][1], message, 'error message as expected');
 
- this.env.log.error.resetHistory();
- } else {
- const message = 'Text track "foobar" is not working correctly. It will be disabled and excluded.';
+  this.env.log.error.resetHistory();
+  } else {
+  const message = 'Text track "foobar" is not working correctly. It will be disabled and excluded.';
 
- assert.equal(this.mpcErrors, 0, 'no mpc error set');
- assert.notOk(this.player.error(), 'no player error set');
- assert.equal(this.player.textTracks().removeTrack.callCount, 1, 'text track remove called');
- assert.equal(this.player.textTracks().removeTrack.args[0][0], track, 'text track remove called with expected');
- assert.equal(track.mode, 'disabled', 'mode set to disabled now');
- assert.equal(this.env.log.warn.callCount, 1, 'warning logged');
- assert.equal(this.env.log.warn.args[0][0], message, 'warning message as expected');
+  assert.equal(this.mpcErrors, 0, 'no mpc error set');
+  assert.notOk(this.player.error(), 'no player error set');
+  assert.equal(this.player.textTracks().removeTrack.callCount, 1, 'text track remove called');
+  assert.equal(this.player.textTracks().removeTrack.args[0][0], track, 'text track remove called with expected');
+  assert.equal(track.mode, 'disabled', 'mode set to disabled now');
+  assert.equal(this.env.log.warn.callCount, 1, 'warning logged');
+  assert.equal(this.env.log.warn.args[0][0], message, 'warning message as expected');
 
- this.env.log.warn.resetHistory();
- }
- });
+  this.env.log.warn.resetHistory();
+  }
+  });
 
- if (type !== 'subtitle') {
  QUnit.test(`detects ${type} appends without buffer changes and excludes many playlists`, function(assert) {
  this.setup({src: 'multipleAudioGroupsCombinedMain.m3u8', type: 'application/vnd.apple.mpegurl'});