Endless buffering after temporary network outage

[zangue]

Have you read the FAQ and checked for duplicate open issues?
Yes

What version of Shaka Player are you using?
v4.3.5-uncompiled

Can you reproduce the issue with our latest release version?
Yes

Can you reproduce the issue with the latest code from main?
Yes

Are you using the demo app or your own custom app?
Demo app

If custom app, can you reproduce the issue using our demo app?
Yes

What browser and OS are you using?
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

For embedded devices (smart TVs, etc.), what model and firmware version are you using?
n/a

What are the manifest and license server URIs?

https://shaka-player-demo.appspot.com/demo/#audiolang=en-GB;textlang=en-GB;uilang=en-GB;asset=https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps.mpd;panel=CUSTOM%20CONTENT;build=uncompiled

What configuration are you using? What is the output of player.getConfiguration()?

'{"drm":{"retryParameters":{"maxAttempts":2,"baseDelay":1000,"backoffFactor":2,"fuzzFactor":0.5,"timeout":30000,"stallTimeout":5000,"connectionTimeout":10000},"servers":{},"clearKeys":{},"advanced":{"com.widevine.alpha":{"distinctiveIdentifierRequired":false,"persistentStateRequired":false,"videoRobustness":"","audioRobustness":"","sessionType":"","serverCertificate":{},"serverCertificateUri":"","individualizationServer":""},"com.microsoft.playready":{"distinctiveIdentifierRequired":false,"persistentStateRequired":false,"videoRobustness":"","audioRobustness":"","sessionType":"","serverCertificate":{},"serverCertificateUri":"","individualizationServer":""},"com.apple.fps":{"distinctiveIdentifierRequired":false,"persistentStateRequired":false,"videoRobustness":"","audioRobustness":"","sessionType":"","serverCertificate":{},"serverCertificateUri":"","individualizationServer":""},"com.adobe.primetime":{"distinctiveIdentifierRequired":false,"persistentStateRequired":false,"videoRobustness":"","audioRobustness":"","sessionType":"","serverCertificate":{},"serverCertificateUri":"","individualizationServer":""},"org.w3.clearkey":{"distinctiveIdentifierRequired":false,"persistentStateRequired":false,"videoRobustness":"","audioRobustness":"","sessionType":"","serverCertificate":{},"serverCertificateUri":"","individualizationServer":""}},"delayLicenseRequestUntilPlayed":false,"logLicenseExchange":false,"updateExpirationTime":1,"preferredKeySystems":[],"keySystemsMapping":{},"parseInbandPsshEnabled":false},"manifest":{"retryParameters":{"maxAttempts":2,"baseDelay":1000,"backoffFactor":2,"fuzzFactor":0.5,"timeout":30000,"stallTimeout":5000,"connectionTimeout":10000},"availabilityWindowOverride":null,"disableAudio":false,"disableVideo":false,"disableText":false,"disableThumbnails":false,"defaultPresentationDelay":0,"segmentRelativeVttTiming":false,"dash":{"clockSyncUri":"https://shaka-player-demo.appspot.com/time.txt","ignoreDrmInfo":false,"disableXlinkProcessing":false,"xlinkFailGracefully":false,"ignoreMinBufferTime":false,"autoCorrectDrift":true,"initialSegmentLimit":1000,"ignoreSuggestedPresentationDelay":false,"ignoreEmptyAdaptationSet":false,"ignoreMaxSegmentDuration":false,"keySystemsByURI":{"urn:uuid:1077efec-c0b2-4d02-ace3-3c1e52e2fb4b":"org.w3.clearkey","urn:uuid:e2719d58-a985-b3c9-781a-b030af78d30e":"org.w3.clearkey","urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed":"com.widevine.alpha","urn:uuid:9a04f079-9840-4286-ab92-e65be0885f95":"com.microsoft.playready","urn:uuid:79f0049a-4098-8642-ab92-e65be0885f95":"com.microsoft.playready","urn:uuid:f239e769-efa3-4850-9c16-a903c6932efb":"com.adobe.primetime"},"sequenceMode":false},"hls":{"ignoreTextStreamFailures":false,"ignoreImageStreamFailures":false,"defaultAudioCodec":"mp4a.40.2","defaultVideoCodec":"avc1.42E01E","ignoreManifestProgramDateTime":false,"mediaPlaylistFullMimeType":"video/mp2t; codecs=\\"avc1.42E01E, mp4a.40.2\\"","useSafariBehaviorForLive":true,"liveSegmentsDelay":3}},"streaming":{"retryParameters":{"maxAttempts":2,"baseDelay":1000,"backoffFactor":2,"fuzzFactor":0.5,"timeout":30000,"stallTimeout":5000,"connectionTimeout":10000},"rebufferingGoal":2,"bufferingGoal":10,"bufferBehind":30,"ignoreTextStreamFailures":false,"alwaysStreamText":false,"startAtSegmentBoundary":false,"gapDetectionThreshold":0.5,"durationBackoff":1,"forceTransmux":false,"safeSeekOffset":5,"stallEnabled":true,"stallThreshold":1,"stallSkip":0.1,"useNativeHlsOnSafari":true,"inaccurateManifestTolerance":2,"lowLatencyMode":false,"autoLowLatencyMode":false,"forceHTTPS":false,"preferNativeHls":false,"updateIntervalSeconds":1,"dispatchAllEmsgBoxes":false,"observeQualityChanges":false,"maxDisabledTime":30,"parsePrftBox":false},"mediaSource":{"sourceBufferExtraFeatures":""},"offline":{"usePersistentLicense":true,"numberOfParallelDownloads":5},"abr":{"enabled":true,"useNetworkInformation":true,"defaultBandwidthEstimate":1000000,"switchInterval":8,"bandwidthUpgradeTarget":0.85,"bandwidthDowngradeTarget":0.95,"restrictions":{"minWidth":0,"maxWidth":null,"minHeight":0,"maxHeight":null,"minPixels":0,"maxPixels":null,"minFrameRate":0,"maxFrameRate":null,"minBandwidth":0,"maxBandwidth":null},"advanced":{"minTotalBytes":128000,"minBytes":16000,"fastHalfLife":2,"slowHalfLife":5},"restrictToElementSize":false,"restrictToScreenSize":false,"ignoreDevicePixelRatio":false},"autoShowText":3,"preferredAudioLanguage":"en-GB","preferredTextLanguage":"en-GB","preferredVariantRole":"","preferredTextRole":"","preferredAudioChannelCount":2,"preferredVideoCodecs":[],"preferredAudioCodecs":[],"preferForcedSubs":false,"preferredDecodingAttributes":[],"restrictions":{"minWidth":0,"maxWidth":null,"minHeight":0,"maxHeight":null,"minPixels":0,"maxPixels":null,"minFrameRate":0,"maxFrameRate":null,"minBandwidth":0,"maxBandwidth":null},"playRangeStart":0,"playRangeEnd":null,"cmcd":{"enabled":false,"sessionId":"","contentId":"","useHeaders":false},"lcevc":{"enabled":false,"dynamicPerformanceScaling":true,"logLevel":0,"drawLogo":false}}'

What did you do?

1. Follow link above
2. Open developer tools and switch to network tab
3. Start playback
4. From the network tab select a request and block associated domain
5. Wait
6. Unblock request domain as soon as the video start buffering (buffering animation visible)
7. You should see segment download resuming (HTTP 200) in the network tab.

What did you expect to happen?
Playback resumes after domain is unblocked

What actually happened?

Video remains buffering forever although new segments have been downloaded

[zangue]

This issue relates to #5055 and both are side effects of #4189. I'm working on a PR to address it.

[zangue]

The PR is going to introduce some changes and I’d like to discuss them here first as per the contribution guidelines.

When trying to upgrade from Shaka 3 to Shaka 4 we noticed couple of issues related the newly added feature in #4189. The two main issues we have are documented here and in #5055.

Furthermore, we could identify following issues with the current implementation:

• When a stream fails due to network error we currently only disable the active variant. However, a stream may be present in multiple variants. Thus, to properly disableba stream we should disable all variants containing it.
• Also, we think it makes sense to disable a stream only if we have an alternative stream we can switch to. Else we may end up disabling all variants. This point is not considered in the current implementation.
• When a network error is successfully recovered no error is forwarded to the application. We think the a recoverable network error should be sent in case we recovered (This is of interest for player analytics purposes)
• The (active) check-variants-timer is reseted each time a variant is disabled (https://github.com/shaka-project/shaka-player/blob/v4.3.5/lib/player.js#L6105). This may cause a previous stream to be disabled much longer than configured time.

Finally, should a temporarily disabled variant be selectable (via selectVariantTrack()) or should it be removed from the variant list? I’m not sure about the best strategy but imo temporarily disabled variant should remain selectable.

I’d be happy to get some feedback.