DASH: Be more optimistic on the buffer depth of DASH contents

src/parsers/manifest/dash/common/__tests__/manifest_bounds_calculator.test.ts

@@ -9,9 +9,9 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
       availabilityStartTime: 0,
       serverTimestampOffset: undefined,
     });
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(undefined);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(undefined);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(undefined);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(undefined);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(3)).toEqual(undefined);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(5)).toEqual(undefined);
   });
 
   it("should return 0 through `getEstimatedMinimumSegmentTime` for a static content", () => {
@@ -21,10 +21,10 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
       availabilityStartTime: 0,
       serverTimestampOffset: 555555,
     });
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(0);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(0);
     manifestBoundsCalculator.setLastPosition(5555, 2135);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(0);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(0);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(4)).toEqual(0);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(5)).toEqual(0);
   });
 
   it("should return 0 through `getEstimatedMinimumSegmentTime` if the `serverTimestampOffset` was never set nor the last position for a dynamic content with no timeShiftBufferDepth", () => {
@@ -34,9 +34,9 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
       availabilityStartTime: 0,
       serverTimestampOffset: undefined,
     });
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(0);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(0);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(0);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(0);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(5)).toEqual(0);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(28)).toEqual(0);
   });
 
   it("should return `false` through `lastPositionIsKnown` if `setLastPositionOffset` was never called", () => {
@@ -47,7 +47,7 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
       serverTimestampOffset: undefined,
     });
     expect(manifestBoundsCalculator.lastPositionIsKnown()).toEqual(false);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(undefined);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(undefined);
     expect(manifestBoundsCalculator.lastPositionIsKnown()).toEqual(false);
   });
 
@@ -86,9 +86,10 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
     });
     manifestBoundsCalculator.setLastPosition(1000, 10);
     performanceNow = 25000;
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(1010);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(1010);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(50)).toEqual(960);
     performanceNow = 35000;
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(1020);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(1020);
     mockPerformanceNow.mockRestore();
   });
 
@@ -104,18 +105,27 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
       serverTimestampOffset: 7000,
     });
     manifestBoundsCalculator.setLastPosition(3000, 10);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(
       7 + 5 - 4 - 3,
     );
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(4)).toEqual(
+      7 + 5 - 4 - 3 - 4,
+    );
     performanceNow = 25000;
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(
       7 + 25 - 4 - 3,
     );
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(10)).toEqual(
+      7 + 25 - 4 - 3 - 10,
+    );
     performanceNow = 35000;
     manifestBoundsCalculator.setLastPosition(84546464, 5642);
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(
       7 + 35 - 4 - 3,
     );
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(5)).toEqual(
+      7 + 35 - 4 - 3 - 5,
+    );
     mockPerformanceNow.mockRestore();
   });
 
@@ -132,10 +142,12 @@ describe("DASH parsers - ManifestBoundsCalculator", () => {
     });
     manifestBoundsCalculator.setLastPosition(1000, 0);
     performanceNow = 50000;
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(1045);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(1045);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(40)).toEqual(1005);
     manifestBoundsCalculator.setLastPosition(0, 0);
     performanceNow = 55000;
-    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime()).toEqual(50);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(0)).toEqual(50);
+    expect(manifestBoundsCalculator.getEstimatedMinimumSegmentTime(40)).toEqual(10);
     mockPerformanceNow.mockRestore();
   });
 

src/parsers/manifest/dash/common/indexes/template.ts

@@ -557,7 +557,9 @@ export default class TemplateRepresentationIndex implements IRepresentationIndex
     }
 
     const { duration, timescale } = this._index;
-    const firstPosition = this._manifestBoundsCalculator.getEstimatedMinimumSegmentTime();
+    const firstPosition = this._manifestBoundsCalculator.getEstimatedMinimumSegmentTime(
+      duration / timescale,
+    );
     if (firstPosition === undefined) {
       return undefined;
     }

src/parsers/manifest/dash/common/indexes/timeline/timeline_representation_index.ts

@@ -796,7 +796,9 @@ export default class TimelineRepresentationIndex implements IRepresentationIndex
     if (!this._isDynamic) {
       return;
     }
-    const firstPosition = this._manifestBoundsCalculator.getEstimatedMinimumSegmentTime();
+    const firstPosition = this._manifestBoundsCalculator.getEstimatedMinimumSegmentTime(
+      (this._index.timeline[0]?.duration ?? 0) / this._index.timescale,
+    );
     if (isNullOrUndefined(firstPosition)) {
       return; // we don't know yet
     }

src/parsers/manifest/dash/common/manifest_bounds_calculator.ts

@@ -109,10 +109,14 @@ export default class ManifestBoundsCalculator {
   /**
    * Estimate a minimum bound for the content from the last set segment time
    * and buffer depth.
-   * Consider that it is only an estimation, not the real value.
+   * Consider that it is only an estimate, not the real value.
+   * @param {number} segmentDuration - In DASH, the buffer depth actually also
+   * depend on a corresponding's segment duration (e.g. a segment become
+   * unavailable once the `timeShiftBufferDepth` + its duration has elapsed).
+   * This argument can thus be set the approximate duration of a segment.
    * @return {number|undefined}
    */
-  getEstimatedMinimumSegmentTime(): number | undefined {
+  getEstimatedMinimumSegmentTime(segmentDuration: number): number | undefined {
     if (!this._isDynamic || this._timeShiftBufferDepth === null) {
       return 0;
     }
@@ -121,7 +125,7 @@ export default class ManifestBoundsCalculator {
     if (maximumBound === undefined) {
       return undefined;
     }
-    const minimumBound = maximumBound - this._timeShiftBufferDepth;
+    const minimumBound = maximumBound - (this._timeShiftBufferDepth + segmentDuration);
     return minimumBound;
   }
 

src/parsers/manifest/dash/common/parse_mpd.ts

@@ -258,6 +258,7 @@ function parseCompleteIntermediateRepresentation(
     args.referenceDateTime,
   );
   const timeShiftBufferDepth = rootAttributes.timeShiftBufferDepth;
+  const maxSegmentDuration = rootAttributes.maxSegmentDuration;
   const { externalClockOffset: clockOffset, unsafelyBaseOnPreviousManifest } = args;
 
   const { externalClockOffset } = args;
@@ -279,7 +280,6 @@ function parseCompleteIntermediateRepresentation(
     manifestBoundsCalculator,
     manifestProfiles: mpdIR.attributes.profiles,
     receivedTime: args.manifestReceivedTime,
-    timeShiftBufferDepth,
     unsafelyBaseOnPreviousManifest,
     xlinkInfos,
     xmlNamespaces: mpdIR.attributes.namespaces,
@@ -381,6 +381,20 @@ function parseCompleteIntermediateRepresentation(
     // can go even lower in terms of depth
     minimumTime = minimumSafePosition;
     timeshiftDepth = timeShiftBufferDepth ?? null;
+    if (timeshiftDepth !== null) {
+      // The DASH spec implies that a segment is still available after a given
+      // `timeShiftBufferDepth` for a time equal to its duration
+      // (What I interpret from "ISO/IEC 23009-1 fifth edition 2022-08
+      // A.3.4 Media Segment list restrictions).
+      //
+      // This `timeshiftDepth` property is global for the whole Manifest (and
+      // not per segment), thus we cannot do exactly that, but we can take the
+      // anounced `maxSegmentDuration` by default instead. This may be a little
+      // too optimistic, but would in reality not lead to a lot of issues as
+      // this `timeshiftDepth` property is not the one that should be relied on
+      // to know which segment can or cannot be requested anymore.
+      timeshiftDepth += maxSegmentDuration ?? 0;
+    }
     if (
       timeshiftDepth !== null &&
       minimumTime !== undefined &&

tests/integration/scenarios/dash_live.test.js

@@ -250,8 +250,8 @@ describe("DASH live content (SegmentTimeline)", function () {
       });
 
       expect(manifestLoaderCalledTimes).to.equal(1);
-      await checkAfterSleepWithBackoff(null, () => {
-        expect(player.getMinimumPosition()).to.be.closeTo(1527507768, 1);
+      await checkAfterSleepWithBackoff({ maxTimeMs: 2000 }, () => {
+        expect(player.getMinimumPosition()).to.be.closeTo(1527507763, 1);
       });
     });
   });

tests/integration/scenarios/dash_live_multi_periods.test.js

@@ -57,7 +57,7 @@ describe("DASH live content multi-periods (SegmentTemplate)", function () {
     const maxPos = player.getMaximumPosition();
     expect(maxPos).to.be.closeTo(now, 2);
     const minPos = player.getMinimumPosition();
-    expect(minPos).to.be.closeTo(now - manifestInfos.tsbd, 2);
+    expect(minPos).to.be.closeTo(now - manifestInfos.tsbd - 2, 2);
     expect(manifestLoaderCalledTimes).to.equal(1);
   });
 });

tests/integration/scenarios/dash_live_utc_timings.test.js

@@ -31,7 +31,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1553521448, 3);
+            expect(player.getMinimumPosition()).to.be.closeTo(1553521446, 3);
             expect(player.getMaximumPosition()).to.be.closeTo(1553521748, 3);
           },
           untilSuccess() {
@@ -56,7 +56,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1553521748, 1);
+            expect(player.getMinimumPosition()).to.be.closeTo(1553521746, 1);
             expect(player.getMaximumPosition()).to.be.closeTo(1553522048, 1);
           },
           untilSuccess() {
@@ -95,7 +95,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1558791848, 3);
+            expect(player.getMinimumPosition()).to.be.closeTo(1558791846, 3);
           },
           untilSuccess() {
             expect(player.getMinimumPosition()).to.equal(null);
@@ -119,7 +119,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1553521748, 1);
+            expect(player.getMinimumPosition()).to.be.closeTo(1553521746, 1);
             expect(player.getMaximumPosition()).to.be.closeTo(1553522048, 1);
           },
           untilSuccess() {
@@ -158,7 +158,7 @@ describe("DASH live - UTCTimings", () => {
               Date.now() / 1000 - manifestInfos.availabilityStartTime;
             const minimumPosition = maximumPosition - timeShiftBufferDepth;
 
-            expect(player.getMinimumPosition()).to.be.closeTo(minimumPosition, 3);
+            expect(player.getMinimumPosition()).to.be.closeTo(minimumPosition - 2, 3);
             expect(player.getMaximumPosition()).to.be.closeTo(maximumPosition, 3);
           },
           untilSuccess() {
@@ -184,7 +184,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1553521748, 1);
+            expect(player.getMinimumPosition()).to.be.closeTo(1553521746, 1);
             expect(player.getMaximumPosition()).to.be.closeTo(1553522048, 1);
           },
           untilSuccess() {
@@ -218,7 +218,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1553521448, 3);
+            expect(player.getMinimumPosition()).to.be.closeTo(1553521446, 3);
           },
           untilSuccess() {
             expect(player.getMinimumPosition()).to.equal(null);
@@ -242,7 +242,7 @@ describe("DASH live - UTCTimings", () => {
         { maxTimeMs: 1000 },
         {
           resolveWhen() {
-            expect(player.getMinimumPosition()).to.be.closeTo(1553521748, 1);
+            expect(player.getMinimumPosition()).to.be.closeTo(1553521746, 1);
             expect(player.getMaximumPosition()).to.be.closeTo(1553522048, 1);
           },
           untilSuccess() {