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Fix selection with small samples and exceptions after destroy #7939

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Merged
robwalch merged 1 commit into from
Jul 20, 2026
+64 −33
Merged

Fix selection with small samples and exceptions after destroy #7939

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90 changes: 59 additions & 31 deletions src/controller/abr-controller.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,7 @@ import type { Level, VideoRange } from '../types/level';
import type { LoaderStats } from '../types/loader';

class AbrController extends Logger implements AbrComponentAPI {
protected hls: Hls;
protected hls: Hls; // TODO: Make nullable in v1.8 | null;
private lastLevelLoadSec: number = 0;
private lastLoadedFragLevel: number = -1;
private firstSelection: number = -1;
Expand Down Expand Up @@ -63,6 +63,9 @@ class AbrController extends Logger implements AbrComponentAPI {
}

public resetEstimator(abrEwmaDefaultEstimate?: number) {
if (!this.hls) {
return;
}
if (abrEwmaDefaultEstimate) {
this.log(`setting initial bwe to ${abrEwmaDefaultEstimate}`);
this.hls.config.abrEwmaDefaultEstimate = abrEwmaDefaultEstimate;
Expand All @@ -72,7 +75,7 @@ class AbrController extends Logger implements AbrComponentAPI {
}

private initEstimator(): EwmaBandWidthEstimator {
const config = this.hls.config;
const config = this.hls!.config;
return new EwmaBandWidthEstimator(
config.abrEwmaSlowVoD,
config.abrEwmaFastVoD,
Expand All @@ -81,7 +84,7 @@ class AbrController extends Logger implements AbrComponentAPI {
}

protected registerListeners() {
const { hls } = this;
const hls = this.hls!;
hls.on(Events.MANIFEST_LOADING, this.onManifestLoading, this);
hls.on(Events.FRAG_LOADING, this.onFragLoading, this);
hls.on(Events.FRAG_LOADED, this.onFragLoaded, this);
Expand Down Expand Up @@ -114,7 +117,11 @@ class AbrController extends Logger implements AbrComponentAPI {
this.clearTimer();
// @ts-ignore
this.hls = this._abandonRulesCheck = this.supportedCache = null;
this.fragCurrent = this.partCurrent = null;
this.audioTracksByGroup =
this.codecTiers =
this.fragCurrent =
this.partCurrent =
null;
}

protected onManifestLoading(
Expand Down Expand Up @@ -217,7 +224,7 @@ class AbrController extends Logger implements AbrComponentAPI {
}

protected onLevelLoaded(event: Events.LEVEL_LOADED, data: LevelLoadedData) {
const config = this.hls.config;
const config = this.hls!.config;
const { loading } = data.stats;
const timeLoadingMs = loading.end - loading.first;
if (Number.isFinite(timeLoadingMs)) {
Expand All @@ -239,6 +246,9 @@ class AbrController extends Logger implements AbrComponentAPI {
*/
private _abandonRulesCheck = (levelLoaded?: Level) => {
const { fragCurrent: frag, partCurrent: part, hls } = this;
if (!hls) {
return;
}
const { autoLevelEnabled, media } = hls;
if (!frag || !media) {
return;
Expand Down Expand Up @@ -415,9 +425,10 @@ class AbrController extends Logger implements AbrComponentAPI {
const abortAndSwitch = () => {
// Are nextLoadLevel details available or is stream-controller still in "WAITING_LEVEL" state?
this.clearTimer();
const hls = this.hls!;
if (
this.fragCurrent === frag &&
this.hls.loadLevel === nextLoadLevel &&
hls.loadLevel === nextLoadLevel &&
nextLoadLevel > 0
) {
const bufferStarvationDelay = this.getStarvationDelay();
Expand All @@ -429,7 +440,7 @@ class AbrController extends Logger implements AbrComponentAPI {
this.fragCurrent = this.partCurrent = null;
if (nextLoadLevel > minAutoLevel) {
let lowestSwitchLevel = this.findBestLevel(
this.hls.levels[minAutoLevel].bitrate,
hls.levels[minAutoLevel].bitrate,
minAutoLevel,
nextLoadLevel,
0,
Expand All @@ -440,12 +451,9 @@ class AbrController extends Logger implements AbrComponentAPI {
if (lowestSwitchLevel === -1) {
lowestSwitchLevel = minAutoLevel;
}
this.hls.nextLoadLevel = this.hls.nextAutoLevel = lowestSwitchLevel;
this.firstAutoFloor = Math.min(
lowestSwitchLevel,
this.hls.firstLevel,
);
this.resetEstimator(this.hls.levels[lowestSwitchLevel].bitrate);
hls.nextLoadLevel = hls.nextAutoLevel = lowestSwitchLevel;
this.firstAutoFloor = Math.min(lowestSwitchLevel, hls.firstLevel);
this.resetEstimator(hls.levels[lowestSwitchLevel].bitrate);
}
}
};
Expand Down Expand Up @@ -479,7 +487,7 @@ class AbrController extends Logger implements AbrComponentAPI {
this.firstSelection = -1;

// compute level average bitrate
if (this.hls.config.abrMaxWithRealBitrate) {
if (this.hls?.config.abrMaxWithRealBitrate) {
const duration = part ? part.duration : frag.duration;
const level = this.hls.levels[frag.level];
const loadedBytes =
Expand Down Expand Up @@ -520,8 +528,11 @@ class AbrController extends Logger implements AbrComponentAPI {
// Use the difference between parsing and request instead of buffering and request to compute fragLoadingProcessing;
// rationale is that buffer appending only happens once media is attached. This can happen when config.startFragPrefetch
// is used. If we used buffering in that case, our BW estimate sample will be very large.
// Except with low-bitrate (< 100 kbps) where round-trip worker parse time inflates samples.
const processingEnd =
(frag.bitrate || 0) >= 100000 ? stats.parsing.end : stats.loading.end;
const processingMs =
stats.parsing.end -
processingEnd -
stats.loading.start -
Math.min(
stats.loading.first - stats.loading.start,
Expand Down Expand Up @@ -552,22 +563,27 @@ class AbrController extends Logger implements AbrComponentAPI {
}

public get firstAutoLevel(): number {
const { maxAutoLevel, minAutoLevel } = this.hls;
const { hls } = this;
if (!hls) {
return 0;
}
const { maxAutoLevel, minAutoLevel } = hls;
const bwEstimate = this.getBwEstimate();
const maxStartDelay = this.hls.config.maxStarvationDelay;
const bufferStarvationDelay = this.getStarvationDelay();
const maxStartDelay = hls.config.maxStarvationDelay;
const abrAutoLevel = this.findBestLevel(
bwEstimate,
minAutoLevel,
maxAutoLevel,
0,
bufferStarvationDelay / 2,
maxStartDelay,
1,
1,
);
if (abrAutoLevel > -1) {
return abrAutoLevel;
}
const firstLevel = this.hls.firstLevel;
const firstLevel = hls.firstLevel;
const firstAutoFloor =
this.firstAutoFloor === -1 ? Infinity : this.firstAutoFloor;
const clamped = Math.min(
Expand All @@ -590,6 +606,9 @@ class AbrController extends Logger implements AbrComponentAPI {

// return next auto level
public get nextAutoLevel(): number {
if (!this.hls) {
return -1;
}
const forcedAutoLevel = this.forcedAutoLevel;
const bwEstimator = this.bwEstimator;
const useEstimate = bwEstimator.canEstimate();
Expand Down Expand Up @@ -634,6 +653,9 @@ class AbrController extends Logger implements AbrComponentAPI {

private getNextABRAutoLevel(): number {
const { fragCurrent, partCurrent, hls } = this;
if (!hls) {
return -1;
}
if (hls.levels.length <= 1) {
return hls.loadLevel;
}
Expand Down Expand Up @@ -727,7 +749,7 @@ class AbrController extends Logger implements AbrComponentAPI {

private getStarvationDelay(): number {
const hls = this.hls;
const media = hls.media;
const media = hls?.media;
if (!media) {
return Infinity;
}
Expand All @@ -740,9 +762,7 @@ class AbrController extends Logger implements AbrComponentAPI {
}

private getBwEstimate(): number {
return this.bwEstimator.canEstimate()
? this.bwEstimator.getEstimate()
: this.hls.config.abrEwmaDefaultEstimate;
return this.bwEstimator.getEstimate();
}

private findBestLevel(
Expand All @@ -754,17 +774,20 @@ class AbrController extends Logger implements AbrComponentAPI {
bwFactor: number,
bwUpFactor: number,
): number {
const { hls, lastLoadedFragLevel, fragCurrent, partCurrent } = this;
if (!hls) {
return -1;
}
const maxFetchDuration: number = bufferStarvationDelay + maxStarvationDelay;
const lastLoadedFragLevel = this.lastLoadedFragLevel;
const selectionBaseLevel =
lastLoadedFragLevel === -1 ? this.hls.firstLevel : lastLoadedFragLevel;
const { fragCurrent, partCurrent } = this;
const { levels, allAudioTracks, loadLevel, config } = this.hls;
lastLoadedFragLevel === -1 ? hls.firstLevel : lastLoadedFragLevel;
const { levels, allAudioTracks, loadLevel, latestLevelDetails, config } =
hls;
if (levels.length === 1) {
return 0;
}
const level = levels[selectionBaseLevel] as Level | undefined;
const live = !!this.hls.latestLevelDetails?.live;
const live = !!latestLevelDetails?.live;
const firstSelection = loadLevel === -1 || lastLoadedFragLevel === -1;
let currentCodecSet: string | undefined;
let currentVideoRange: VideoRange | undefined = 'SDR';
Expand Down Expand Up @@ -926,7 +949,9 @@ class AbrController extends Logger implements AbrComponentAPI {
const avgDuration =
(partCurrent
? levelDetails?.partTarget
: levelDetails?.averagetargetduration) || currentFragDuration;
: levelDetails?.averagetargetduration) ||
currentFragDuration ||
1;

let adjustedbw: number;
// follow algorithm captured from stagefright :
Expand Down Expand Up @@ -961,7 +986,7 @@ class AbrController extends Logger implements AbrComponentAPI {
// no level change, new level has no error history or penalty expired because error happened a while ago
(i === lastLoadedFragLevel ||
(levelInfo.loadError === 0 && levelInfo.fragmentError === 0) ||
isPenaltyExpired(levelInfo, this.hls.config.errorPenaltyExpireMs)) &&
isPenaltyExpired(levelInfo, config.errorPenaltyExpireMs)) &&
// fragment fetchDuration unknown OR live stream OR fragment fetchDuration less than max allowed fetch duration, then this level matches
// we don't account for max Fetch Duration for live streams, this is to avoid switching down when near the edge of live sliding window ...
// special case to support startLevel = -1 (bitrateTest) on live streams : in that case we should not exit loop so that findBestLevel will return -1
Expand Down Expand Up @@ -1021,7 +1046,10 @@ class AbrController extends Logger implements AbrComponentAPI {
}
}

protected deriveNextAutoLevel(nextLevel: number) {
protected deriveNextAutoLevel(nextLevel: number): number {
if (!this.hls) {
return -1;
}
const { maxAutoLevel, minAutoLevel } = this.hls;
return Math.min(Math.max(nextLevel, minAutoLevel), maxAutoLevel);
}
Expand Down
7 changes: 5 additions & 2 deletions src/utils/ewma-bandwidth-estimator.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,13 @@ class EwmaBandWidthEstimator {
}

sample(durationMs: number, numBytes: number) {
durationMs = Math.max(durationMs, this.minDelayMs_);
if (numBytes <= 0) {
return;
}
const minDelay = Math.min(this.minDelayMs_, numBytes / 100000);
const numBits = 8 * numBytes;
// weight is duration in seconds
const durationS = durationMs / 1000;
const durationS = Math.max(durationMs, minDelay) / 1000;
// value is bandwidth in bits/s
const bandwidthInBps = numBits / durationS;
this.fast_.sample(durationS, bandwidthInBps);
Expand Down
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