Playback stucks for multi-period dash, DVR and buffer time not strictly increasing

[chanyk-joseph]

Environment

• The MPD passes the DASH-IF Conformance Tool on https://conformance.dashif.org/
• The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream
• The issue observed is not mentioned on https://github.com/Dash-Industry-Forum/dash.js/wiki/FAQ
• The issue occurs in the latest reference client on http://reference.dashif.org/dash.js/ and not just on my page

• Link to playable MPD file: https://4-dot-android-player-265006.uc.r.appspot.com/asset=dashif_issue_ng46534_patched_minimumUpdatePeriod_timeShiftBufferDepth_suggestedPresentationDelay,version=v1,user=harmonic-internal/acheung-desktop.nebula.video_20212/Content/DASH/Live/channel(clear)/manifest.mpd
• Dash.js version: 3.1.3 / 3.1.4
• Browser name/version: Chrome 87.0.4280.66 (Official Build) (64-bit)
• OS name/version: Win10

Steps to reproduce

• Start the playback on chrome
• The playback starts looping the last few frames at ~45s, then stucks at around ~60s
• Always reproducible (100%)

Observed behaviour

• The DVR windows freeze for some time
  
• The DVR windows endtime is not strictly increasing

	Line 1550: 11:02:55.075 ​ [60119][PlaybackController] Checking DVR window for at 76908.681027 with DVR window range 76880.2292214 - 76910.2925881 
	Line 1584: 11:02:56.266 ​ [61310][PlaybackController] Checking DVR window for at 76909.873032 with DVR window range 76880.2292214 - 76910.2925881 
	Line 1585: 11:02:56.267 ​ [61311][PlaybackController] Checking DVR window for at 76909.873032 with DVR window range 76880.2292214 - 76910.2925881 
	Line 1630: 11:02:57.464 ​ [62508][PlaybackController] Checking DVR window for at 76911.069702 with DVR window range 76915.2308548 - 76924.0396548 
	Line 1634: 11:02:57.465 ​ [62509][PlaybackController] Checking DVR window for at 76915.230854 with DVR window range 76915.2308548 - 76924.0396548 
	Line 2167: 11:02:58.665 ​ [63709][PlaybackController] Checking DVR window for at 76915.231463 with DVR window range 76910.2925881 - 76915.2308548 
	Line 2171: 11:02:58.666 ​ [63710][PlaybackController] Checking DVR window for at 76910.334279 with DVR window range 76910.2925881 - 76915.2308548 
	Line 2187: 11:02:58.670 ​ [63714][PlaybackController] Checking DVR window for at 76910.334279 with DVR window range 76880.2292214 - 76910.2925881 
	Line 2191: 11:02:58.672 ​ [63716][PlaybackController] Checking DVR window for at 76910.334279 with DVR window range 76880.2292214 - 76910.2925881 

• The buffered range's end & current time is not strictly increasing

	Line 1358: 11:02:52.400 ​ [57444][BufferController][video] Buffered range: 76877.993654 - 76915.230854, currentTime =  76906.008272 
	Line 1426: 11:02:53.067 ​ [58111][BufferController][audio] Buffered range: 76876.115613 - 76915.230858, currentTime =  76906.675225 
	Line 1479: 11:02:53.787 ​ [58831][BufferController][audio] Buffered range: 76876.115613 - 76918.056945, currentTime =  76907.395299 
	Line 1506: 11:02:53.958 ​ [59001][BufferController][video] Buffered range: 76877.993654 - 76918.033654, currentTime =  76907.565432 
	Line 1512: 11:02:54.371 ​ [59415][BufferController][video] Buffered range: 76877.993654 - 76920.035654, currentTime =  76907.978505 
	Line 1528: 11:02:55.028 ​ [60072][BufferController][audio] Buffered range: 76876.115613 - 76920.062279, currentTime =  76908.635496 
	Line 2075: 11:02:57.477 ​ [62521][BufferController][video] Buffered range: 76910.292588 - 76920.035654, currentTime =  76915.230854 
	Line 2078: 11:02:57.477 ​ [62521][BufferController][audio] Buffered range: 76910.334279 - 76920.062279, currentTime =  76915.230854 
	Line 2103: 11:02:57.479 ​ [62523][BufferController][video] Buffered range: 76910.292588 - 76915.714671, currentTime =  76915.230854 
	Line 2106: 11:02:57.480 ​ [62524][BufferController][audio] Buffered range: 76910.334279 - 76915.752945, currentTime =  76915.230854 
	Line 2111: 11:02:57.481 ​ [62525][BufferController][video] Buffered range: 76910.292588 - 76915.714671, currentTime =  76915.230854 
	Line 2115: 11:02:57.482 ​ [62526][BufferController][audio] Buffered range: 76910.334279 - 76915.752945, currentTime =  76915.230854 
	Line 2118: 11:02:57.482 ​ [62526][BufferController][audio] Buffered range: 76910.334279 - 76915.752945, currentTime =  76915.230982 
	Line 2120: 11:02:57.482 ​ [62526][BufferController][video] Buffered range: 76910.292588 - 76915.714671, currentTime =  76915.231216 
	Line 2660: 11:02:58.692 ​ [63736][BufferController][audio] Buffered range: 76908.030279 - 76910.292591, currentTime =  76910.292588 
	Line 2701: 11:02:59.105 ​ [64149][BufferController][video] Buffered range: 76908.023654 - 76910.292587, currentTime =  76910.292588 

Console output

reference.dashif.org-1606187004655.log

Notes

• The same asset can be played on shaka-player
• Manually convert the asset to static, The playback works fine
• Manually stitch the init with the m4v, and the pts time is strictly increasing
• Tested with https://reference.dashif.org/dash.js/fix-multiperiod/samples/dash-if-reference-player/index.html from Live MultiPeriod $Time$+SegmentTimeline stalls at period boundary #2946 (comment). The playback does not get stuck. So probably a regression issue due to latest update?

[dsilhavy]

Can you please check if playback works as expected when you set calcSegmentAvailabilityRangeFromTimeline to false. An example how to adjust settings can be found here: http://reference.dashif.org/dash.js/nightly/samples/advanced/settings.html

[chanyk-joseph]

Hi @dsilhavy , I have tested the nightly build with calcSegmentAvailabilityRangeFromTimeline=false
The player still stucks after ~60s

$ JSON.stringify(player.getSettings(), null, 3)
"{
   "debug": {
      "logLevel": 5
   },
   "streaming": {
      "metricsMaxListDepth": 50,
      "abandonLoadTimeout": 10000,
      "liveDelayFragmentCount": null,
      "liveDelay": null,
      "scheduleWhilePaused": true,
      "fastSwitchEnabled": true,
      "flushBufferAtTrackSwitch": false,
      "calcSegmentAvailabilityRangeFromTimeline": false,
      "bufferPruningInterval": 10,
      "bufferToKeep": 20,
      "jumpGaps": true,
      "jumpLargeGaps": true,
      "smallGapLimit": 1.5,
      "stableBufferTime": -1,
      "bufferTimeAtTopQuality": 30,
      "bufferTimeAtTopQualityLongForm": 60,
      "longFormContentDurationThreshold": 600,
      "wallclockTimeUpdateInterval": 50,
      "lowLatencyEnabled": false,
      "keepProtectionMediaKeys": false,
      "useManifestDateHeaderTimeSource": true,
      "useSuggestedPresentationDelay": true,
      "useAppendWindow": true,
      "manifestUpdateRetryInterval": 100,
      "liveCatchUpMinDrift": 0.02,
      "liveCatchUpMaxDrift": 0,
      "liveCatchUpPlaybackRate": 0.5,
      "liveCatchupLatencyThreshold": null,
      "lastBitrateCachingInfo": {
         "enabled": true,
         "ttl": 360000
      },
      "lastMediaSettingsCachingInfo": {
         "enabled": true,
         "ttl": 360000
      },
      "cacheLoadThresholds": {
         "video": 50,
         "audio": 5
      },
      "trackSwitchMode": {
         "audio": "alwaysReplace",
         "video": "neverReplace"
      },
      "selectionModeForInitialTrack": "highestBitrate",
      "fragmentRequestTimeout": 0,
      "retryIntervals": {
         "MPD": 500,
         "XLinkExpansion": 500,
         "MediaSegment": 1000,
         "InitializationSegment": 1000,
         "BitstreamSwitchingSegment": 1000,
         "IndexSegment": 1000,
         "other": 1000,
         "lowLatencyReductionFactor": 10
      },
      "retryAttempts": {
         "MPD": 3,
         "XLinkExpansion": 1,
         "MediaSegment": 3,
         "InitializationSegment": 3,
         "BitstreamSwitchingSegment": 3,
         "IndexSegment": 3,
         "other": 3,
         "lowLatencyMultiplyFactor": 5
      },
      "abr": {
         "movingAverageMethod": "slidingWindow",
         "ABRStrategy": "abrDynamic",
         "bandwidthSafetyFactor": 0.9,
         "useDefaultABRRules": true,
         "useDeadTimeLatency": true,
         "limitBitrateByPortal": false,
         "usePixelRatioInLimitBitrateByPortal": false,
         "maxBitrate": {
            "audio": -1,
            "video": -1
         },
         "minBitrate": {
            "audio": -1,
            "video": -1
         },
         "maxRepresentationRatio": {
            "audio": 1,
            "video": 1
         },
         "initialBitrate": {
            "audio": -1,
            "video": -1
         },
         "initialRepresentationRatio": {
            "audio": -1,
            "video": -1
         },
         "autoSwitchBitrate": {
            "audio": true,
            "video": true
         }
      },
      "cmcd": {
         "enabled": false,
         "sid": null,
         "cid": null
      }
   }
}

From the log, the buffered range is not strictly increasing

Details console log:
reference.dashif.org-1606288856252.log

[dsilhavy]

@chanyk-joseph Can you please check if your problem is fixed in 4.0 alpha: https://reference.dashif.org/dash.js/v4.0.0-alpha/samples/dash-if-reference-player/index.html

[chanyk-joseph]

Hi @dsilhavy , the playback is smooth on the 4.0 alpha build

[dsilhavy]

Fixed in 4.0:
http://reference.dashif.org/dash.js/nightly/samples/dash-if-reference-player/index.html