Same fragments loaded multiple times

[mbUSC]

What version of Hls.js are you using?

1.5.11

What browser (including version) are you using?

Chrome 126.0.6478.127 (Mac M2)

What OS (including version) are you using?

MacOS

Test stream

http://djsso3aok5lkq.cloudfront.net/test.html

Configuration

{
      debug: true
}

Additional player setup steps

No response

Checklist

• The issue observed is not already reported by searching on Github under https://github.com/video-dev/hls.js/issues
• The issue occurs in the stable client (latest release) on https://hlsjs.video-dev.org/demo and not just on my page
• The issue occurs in the latest client (main branch) on https://hlsjs-dev.video-dev.org/demo and not just on my page
• 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

Steps to reproduce

1. Open http://djsso3aok5lkq.cloudfront.net/test.html with Chrome / Firefox

It seems like the problem is worse if the connection is fast (e.g. when hosting on localhost).
The problem does not happen with Safari.

Expected behaviour

Each segment downloaded only once

What actually happened?

Same segments downloaded many times

Console output

The following output is repeated over and over:

[log] > [transmuxer-interface, main]: Starting new transmux session for sn: 2 p: -1 level: 2 id: 1
        discontinuity: false
        trackSwitch: false
        contiguous: false
        accurateTimeOffset: true
        timeOffset: 20.138666666666666
        initSegmentChange: false
hls.js@1:1 [log] > [stream-controller]: Loaded fragment 2 of level 2
hls.js@1:1 [log] > [mp4-remuxer]: reset next timestamp
hls.js@1:1 [log] > [stream-controller]: FRAG_LOADING->PARSING
hls.js@1:1 [warn] > [buffer-operation-queue]: Exception executing "video" SourceBuffer operation: QuotaExceededError: Failed to execute 'appendBuffer' on 'SourceBuffer': The SourceBuffer is full, and cannot free space to append additional buffers.
e.executeNext @ hls.js@1:1
e.append @ hls.js@1:1
e.onBufferAppending @ hls.js@1:1
o.emit @ hls.js@1:1
e.emit @ hls.js@1:1
e.trigger @ hls.js@1:1
r.bufferFragmentData @ hls.js@1:1
r._handleTransmuxComplete @ hls.js@1:1
r.handleTransmuxComplete @ hls.js@1:1
r.onWorkerMessage @ hls.js@1:1
onwmsg @ hls.js@1:1
hls.js@1:1 [log] > [stream-controller]: Reset loading state
hls.js@1:1 [log] > [stream-controller]: PARSING->IDLE
hls.js@1:1 [log] > [transmuxer.ts]: Flushed fragment 2 of level 2
hls.js@1:1 [log] > [stream-controller]: Loading fragment 2 cc: 0 of [0-63] level: 2, target: 20.139
hls.js@1:1 [log] > [stream-controller]: IDLE->FRAG_LOADING
hls.js@1:1 [log] > [transmuxer-interface, main]: Starting new transmux session for sn: 2 p: -1 level: 2 id: 1
        discontinuity: false
        trackSwitch: false
        contiguous: false
        accurateTimeOffset: true
        timeOffset: 20.138666666666666
        initSegmentChange: false
hls.js@1:1 [log] > [stream-controller]: Loaded fragment 2 of level 2
hls.js@1:1 [log] > [mp4-remuxer]: reset next timestamp
hls.js@1:1 [log] > [stream-controller]: FRAG_LOADING->PARSING
hls.js@1:1 [warn] > [buffer-operation-queue]: Exception executing "video" SourceBuffer operation: QuotaExceededError: Failed to execute 'appendBuffer' on 'SourceBuffer': The SourceBuffer is full, and cannot free space to append additional buffers.
e.executeNext @ hls.js@1:1
e.append @ hls.js@1:1
e.onBufferAppending @ hls.js@1:1
o.emit @ hls.js@1:1
e.emit @ hls.js@1:1
e.trigger @ hls.js@1:1
r.bufferFragmentData @ hls.js@1:1
r._handleTransmuxComplete @ hls.js@1:1
r.handleTransmuxComplete @ hls.js@1:1
r.onWorkerMessage @ hls.js@1:1
onwmsg @ hls.js@1:1
hls.js@1:1 [log] > [stream-controller]: Reset loading state
hls.js@1:1 [log] > [stream-controller]: PARSING->IDLE
hls.js@1:1 [log] > [transmuxer.ts]: Flushed fragment 2 of level 2
hls.js@1:1 [log] > [stream-controller]: Loading fragment 2 cc: 0 of [0-63] level: 2, target: 20.139
hls.js@1:1 [log] > [stream-controller]: IDLE->FRAG_LOADING
hls.js@1:1

Chrome media internals output

No response

[robwalch]

This is reproducing in v1.5.12 with the fix for #6537. Limiting the max buffer length to the current forward length isn't enough to stop streaming while paused.

[robwalch]

It's worth noting that the peak bitrate for the highest tier in the reproduction vector is vastly under reported:

$ curl https://[...]/playlist.m3u8
[...]
#EXT-X-STREAM-INF:BANDWIDTH=2800000,RESOLUTION=1280x720
big_buck_bunny_43000k.m3u8
[...]

$ mediastreamvalidator https://[...]/playlist.m3u8
[...]
Error: Measured peak bitrate compared to multivariant playlist declared value exceeds error tolerance
--> Detail:  Measured: 97473.55 kb/s, Multivariant playlist: 2800.00 kb/s, Error: 3381.20%
--> Source:  https://djsso3aok5lkq.cloudfront.net/playlist.m3u8
--> Compare: big_buck_bunny_43000k.m3u8
[...]

Correcting this or adding abrMaxWithRealBitrate: true to the config prevents this issue from reproducing.