limitBitrateByPortal option misbehaves for unsorted Representation mpd files

[francox9]

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: unrelated
• Dash.js version: 4.1.0 (4.4.0 failed too)
• Browser name/version: unrelated
• OS name/version: unrelated

Steps to reproduce

1. Use a mpd file with unsorted (in terms of bandwidth / width) Representation, sample:

<Representation id="1" width="852" height="480" frameRate="25/1" bandwidth="1196651" codecs="avc1.64001E">
</Representation>
<Representation id="2" width="1920" height="1080" frameRate="25/1" bandwidth="5354565" codecs="avc1.640028">
</Representation>
<Representation id="3" width="1280" height="720" frameRate="25/1" bandwidth="2629619" codecs="avc1.64001F">
</Representation>
<Representation id="4" width="960" height="540" frameRate="25/1" bandwidth="1414873" codecs="avc1.64001F">
</Representation>
<Representation id="5" width="640" height="360" frameRate="25/1" bandwidth="600000" codecs="avc1.4D401E">
</Representation>

2. Enable streaming.abr.limitBitrateByPortal option

Observed behavior

Resize window and notice abr is not functioning as expected - the minimum bandwidth that has a width larger than current portal size

It seems the reason behind is in AbrController, _checkPortalSize just assumes representation is a sorted array (source) based on bandwith/width from smaller to larger. However representation can be unsorted - it comes from adapter.getAdaptationForType(streamInfo.index, type, streamInfo).Representation (source).

Dash'll need to use adapter.getAdaptationForType(streamInfo.index, type, streamInfo).Representation_asArray instead. And this change solves the issue for me in my local testing.

The other occurrence of the Representation will probably need the same change (source)

Console output

Paste the contents of the browser console here.
You may need to enable debug logging in dash.js by calling player.updateSettings({ 'debug': { 'logLevel': dashjs.Debug.LOG_LEVEL_DEBUG }}) if you are using your own page.

Unrelated

Expected behavior

limitBitrateByPortal should behave correctly for mpd with unsorted Representations

[francox9]

I'll be happy to add in some testing & make out of it a PR if confirmed a proper fix.

[dsilhavy]

@francox9 Thank you for sharing this observation. I implemented the solution you proposed here: #3970 . Can you confirm that this fixes the issue?

[dsilhavy]

Fixed in #3970

[francox9]

@francox9 Thank you for sharing this observation. I implemented the solution you proposed here: #3970 . Can you confirm that this fixes the issue?

thank you!