[Bug] [HLS] IA chooses the wrong audio stream - Ignoring the AUDIO / group-id

[matthuisman]

Describe the problem

With the below, IA will try to use the "233" audio even though the single video stream has AUDIO="234"
With ffmpeg will use and only show the single "234" audio stream.

It might only happen when there is a single video stream.
As if I pass the entire manifest through - IA has the 2nd audio stream listed first and it uses that.
However, it then keeps in-correctly using that for the lowest quality video stream that should use "233"

Possible fix

Remove / ignore audio streams without a matching group-id to the currently playing video stream

Steps to reproduce

1. Create a HLS manifest with 2x audio streams with GROUP-ID="1" and GROUP-ID="2" in that order
   Have DEFAULT NO and AUTOSELECT YES on both
2. Add single video stream with AUDIO="2"
3. Play the HLS
4. Observe IA will just select the first audio stream - when it should use the 2nd
5. ffmpeg doesn't even show the first audio stream

Debug log

..

Stream manifest file(s)

#EXTM3U
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-MEDIA:URI="https://example.com/audio/playlist/233.m3u8",TYPE="AUDIO",GROUP-ID="233",NAME="Default",DEFAULT="NO",AUTOSELECT="YES"
#EXT-X-MEDIA:URI="https://example.com/audio/playlist/234.m3u8",TYPE="AUDIO",GROUP-ID="234",NAME="Default",DEFAULT="NO",AUTOSELECT="YES"
#EXT-X-STREAM-INF:BANDWIDTH=7171631,CODECS="avc1.64002A,mp4a.40.2",RESOLUTION=1920x1080,FRAME-RATE=60,VIDEO-RANGE=SDR,AUDIO="234",CLOSED-CAPTIONS=NONE
https://manifest.googlevideo.com/api/manifest/hls_playlist/expire/1787380794/playlist/video.m3u8

Additional info

No response

Operating system(s)

Windows

Operating system version(s)

11

InputStream Adaptive version(s)

22.3.20

Kodi version(s)

22

[CastagnaIT]

i see that you written kodi 21.5.23, have you tested on v22?
i would like to avoid wasting time figuring out if it works on v22

[matthuisman]

Oh i was in Kodi 22 - but maybe IA hadn't updated.
Ill try again

[matthuisman]

I tried on 22 and it still selects the first audio stream instead of the one for its own group.
I did update my proxy to remove audio streams with group that dont match so it matches ffmpeg behaviour.

The first audio stream does actually work in 22 - but it takes about 10-15 seconds for it to start.
If i change audio stream - it starts working immediately.
Suspect this be an issue with HE-AAC
I might open an issue for that too - as the lower quality streams have this as there default stream and the delay is "odd"
ffmpeg doesnt have such a delay

Id like to keep this issue towards the audio stream behaviour though as I think thats valid?

[matthuisman]

Ill create a new ticket for the slow audio start on HE-ACC

I have reworked this ticket to just be about the chosen audio stream :)

[CastagnaIT]

HLS parser dont take in account of Group ID to "select" streams, its used only to retrieve tracks info
in your case have two tracks with same attributes
so there is no way to know the differences between these tracks while parsing the manifest metadata, and so in playback will choose the first one

i think one solution consist in to collect all EXT-X-STREAM-INF GROUP ID's (audio and subs renditions) and then delete all renditions not defined in any variants

[matthuisman]

Is this because you can't add/remove audio tracks during Kodi playback?

I was thinking you'd only enable the matching audio group tracks for the currently playing video

I guess as ffmpeg doesn't do adaptive, it only picks a single video so can remove the other audios.

I guess at a minimum maybe could set the default or order so the matching audio comes first?

That won't help when you switch video tracks but should at least always pick the correct audio on start?