feat: Add experimentalExactManifestTimings which forgoes TIME_FUDGE_F…

…ACTOR during segment choice (#1165)
videojs · Jul 27, 2021 · 67a1201 · 67a1201
1 parent a0c0359
commit 67a1201
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Showing 7 changed files with 568 additions and 542 deletions.
diff --git a/index.html b/index.html
@@ -84,6 +84,10 @@ <h3>Options</h3>
       <input id=buffer-water type="checkbox">
       [EXPERIMENTAL] Use Buffer Level for ABR (reloads player)
     </label>
+    <label>
+      <input id=exact-manifest-timings type="checkbox">
+      [EXPERIMENTAL] Use exact manifest timings for segment choices (reloads player)
+    </label>
     <label>
       <input id=pixel-diff-selector type="checkbox">
       [EXPERIMENTAL] Use the Pixel difference resolution selector (reloads player)

diff --git a/scripts/index-demo-page.js b/scripts/index-demo-page.js
@@ -245,6 +245,7 @@
     'type',
     'keysystems',
     'buffer-water',
+    'exact-manifest-timings',
     'pixel-diff-selector',
     'override-native',
     'preload',
@@ -285,7 +286,8 @@
       'buffer-water',
       'override-native',
       'liveui',
-      'pixel-diff-selector'
+      'pixel-diff-selector',
+      'exact-manifest-timings'
     ].forEach(function(name) {
       stateEls[name].addEventListener('change', function(event) {
         saveState();
@@ -350,6 +352,7 @@
               overrideNative: getInputValue(stateEls['override-native']),
               experimentalBufferBasedABR: getInputValue(stateEls['buffer-water']),
               experimentalLLHLS: getInputValue(stateEls.llhls),
+              experimentalExactManifestTimings: getInputValue(stateEls['exact-manifest-timings']),
               experimentalLeastPixelDiffSelector: getInputValue(stateEls['pixel-diff-selector'])
             }
           }

diff --git a/src/master-playlist-controller.js b/src/master-playlist-controller.js
@@ -234,7 +234,8 @@ export class MasterPlaylistController extends videojs.EventTarget {
       inbandTextTracks: this.inbandTextTracks_,
       cacheEncryptionKeys,
       sourceUpdater: this.sourceUpdater_,
-      timelineChangeController: this.timelineChangeController_
+      timelineChangeController: this.timelineChangeController_,
+      experimentalExactManifestTimings: options.experimentalExactManifestTimings
     };
 
     // The source type check not only determines whether a special DASH playlist loader

diff --git a/src/playlist.js b/src/playlist.js
@@ -382,7 +382,8 @@ export const getMediaInfoForTime = function({
   currentTime,
   startingSegmentIndex,
   startingPartIndex,
-  startTime
+  startTime,
+  experimentalExactManifestTimings
 }) {
 
   let time = currentTime - startTime;
@@ -415,19 +416,23 @@ export const getMediaInfoForTime = function({
 
         time += partAndSegment.duration;
 
-        // TODO: consider not using TIME_FUDGE_FACTOR at all here
-        if ((time + TIME_FUDGE_FACTOR) > 0) {
-          return {
-            partIndex: partAndSegment.partIndex,
-            segmentIndex: partAndSegment.segmentIndex,
-            startTime: startTime - sumDurations({
-              defaultDuration: playlist.targetDuration,
-              durationList: partsAndSegments,
-              startIndex,
-              endIndex: i
-            })
-          };
+        if (experimentalExactManifestTimings) {
+          if (time < 0) {
+            continue;
+          }
+        } else if ((time + TIME_FUDGE_FACTOR) <= 0) {
+          continue;
         }
+        return {
+          partIndex: partAndSegment.partIndex,
+          segmentIndex: partAndSegment.segmentIndex,
+          startTime: startTime - sumDurations({
+            defaultDuration: playlist.targetDuration,
+            durationList: partsAndSegments,
+            startIndex,
+            endIndex: i
+          })
+        };
       }
     }
 
@@ -446,6 +451,7 @@ export const getMediaInfoForTime = function({
   if (startIndex < 0) {
     for (let i = startIndex; i < 0; i++) {
       time -= playlist.targetDuration;
+
       if (time < 0) {
         return {
           partIndex: partsAndSegments[0] && partsAndSegments[0].partIndex || null,
@@ -464,19 +470,24 @@ export const getMediaInfoForTime = function({
 
     time -= partAndSegment.duration;
 
-    // TODO: consider not using TIME_FUDGE_FACTOR at all here
-    if ((time - TIME_FUDGE_FACTOR) < 0) {
-      return {
-        partIndex: partAndSegment.partIndex,
-        segmentIndex: partAndSegment.segmentIndex,
-        startTime: startTime + sumDurations({
-          defaultDuration: playlist.targetDuration,
-          durationList: partsAndSegments,
-          startIndex,
-          endIndex: i
-        })
-      };
+    if (experimentalExactManifestTimings) {
+      if (time > 0) {
+        continue;
+      }
+    } else if ((time - TIME_FUDGE_FACTOR) >= 0) {
+      continue;
     }
+
+    return {
+      partIndex: partAndSegment.partIndex,
+      segmentIndex: partAndSegment.segmentIndex,
+      startTime: startTime + sumDurations({
+        defaultDuration: playlist.targetDuration,
+        durationList: partsAndSegments,
+        startIndex,
+        endIndex: i
+      })
+    };
   }
 
   // We are out of possible candidates so load the last one...

diff --git a/src/segment-loader.js b/src/segment-loader.js
@@ -539,6 +539,7 @@ export default class SegmentLoader extends videojs.EventTarget {
     this.timelineChangeController_ = settings.timelineChangeController;
     this.shouldSaveSegmentTimingInfo_ = true;
     this.parse708captions_ = settings.parse708captions;
+    this.experimentalExactManifestTimings = settings.experimentalExactManifestTimings;
 
     // private instance variables
     this.checkBufferTimeout_ = null;
@@ -1404,6 +1405,7 @@ export default class SegmentLoader extends videojs.EventTarget {
     } else {
       // Find the segment containing the end of the buffer or current time.
       const {segmentIndex, startTime, partIndex} = Playlist.getMediaInfoForTime({
+        experimentalExactManifestTimings: this.experimentalExactManifestTimings,
         playlist: this.playlist_,
         currentTime: this.fetchAtBuffer_ ? bufferedEnd : this.currentTime_(),
         startingPartIndex: this.syncPoint_.partIndex,

diff --git a/src/videojs-http-streaming.js b/src/videojs-http-streaming.js
@@ -682,6 +682,7 @@ class VhsHandler extends Component {
       'experimentalBufferBasedABR',
       'liveRangeSafeTimeDelta',
       'experimentalLLHLS',
+      'experimentalExactManifestTimings',
       'experimentalLeastPixelDiffSelector'
     ].forEach((option) => {
       if (typeof this.source_[option] !== 'undefined') {