audio glitch with multiple AAC audio track since 20.1

[pat147]

audio glitch with multiple AAC audio track since 20.1

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[CrystalP]

Please attach a debug log (turn on debugging, restart Kodi, play the file, upload the kodi.log of the user data folder to paste.kodi.tv and add the link here) so that the non-compliance tag can be removed

[pat147]

https://paste.kodi.tv/hajadarezo.kodi without the sync activated
https://paste.kodi.tv/utufigikoc.kodi with the sync activated

[CrystalP]

Reproduced on Windows using sample provided in forum. It's a multiplatform issue.
Bisection shows it comes from #22796 later backported as #22870 to nexus

[thexai]

Basically i'm muxing in a mkv file both french and english audio, both are coming from video : Pal for french (25 fps) and ntsc for english (23.976 fps)
The original file is a mkv with x65 video (23.976 fps) and AAC english audio.

You can not take an audio of 25.0 fps video and remux (add) to other 23.976 fps video because time stamps not match.

This is not possible to fix at the remux level (i.e. adding a delay).

You need use some tool like eac3to to convert audio first:
https://forum.doom9.org/showthread.php?t=125966

-slowdown convert 25.000 and 24.000 content to 23.976 fps
-speedup convert 23.976 and 24.000 content to 25.000 fps

That Kodi works poorly with a file that is incorrect is not a bug.

[thexai]

To disable a/v sync "self-learning" algo you can use this in advancedsettings.xml

<advancedsettings>
  <audio>
    <maxpassthroughoffsyncduration>11</maxpassthroughoffsyncduration>
  </audio>
</advancedsettings>

This should result in almost same behavior that older Kodi versions.

Or even try other fixed values up to 100 (if you not want Kodi try to fix a/v sync errors up to 100 ms)

[thexai]

Closed as this file is bad:
https://forum.kodi.tv/showthread.php?tid=376539&pid=3186962#pid3186962

[pat147]

Hi, i try with the advancedsettings.xml but don't works.

You can not take an audio of 25.0 fps video and remux (add) to other 23.976 fps video because time stamps not match

As explained, even if the audio file has not the right side, it's not a pb : if the video is longer : the video continue with sound, if the video is shorter : the player stops the file.

This is not possible to fix at the remux level (i.e. adding a delay).

was working perfectly before kodi 20.1.
and you can do both : strecth the audio and add a delay with Mkvtoolnix in the audio track.

https://forum.doom9.org/showthread.php?t=125966
i was using this before but then i found what I explain above.

anyway, i found a player doing the trick perfectly : smplayer on debian. and on windows MPC-BE

[CrystalP]

As far as I know mkvtoolnix alters the timestamps when using the delay/stretch parameters so the file is probably not "incorrect".
But that would put the burden on the player to maintain a/v sync either by stretching/shrinking the audio (sync playback to display ON) or by skipping/duplicating video frames here and there (sync playback to display OFF).
VLC has the same problem as Kodi, mpv does a good job with the sample it seems.

[thexai]

Google is your friend:
https://forum.videohelp.com/threads/312812-25fps-source-Ac3-to-23-976fps

especially:
https://forum.videohelp.com/threads/312812-25fps-source-Ac3-to-23-976fps/page2#post2347972

As far as I know mkvtoolnix alters the timestamps when using the delay/stretch parameters so the file is probably not "incorrect".

Yes, is INCORRECT

Probably with older Kodi versions was obtained perfect audio and micro-stuttering video (incorrect anyway).

[CrystalP]

See https://gitlab.com/mbunkus/mkvtoolnix/-/wikis/Stretch-or-shrink-audio-tracks
It does scale the timecodes. Adjusting the video stream is recommended instead.