Transcoding fail for mp4 with multiple aac audio channels

[TommasoCostanzo]

Describe the bug

I am using the latest nextcloud-aio with the go-vod (external memories transcoder) activated and properly working for the majority of files. However, the transcoding is failing for ripped DVD files that are in mp4 container, 1 h264 video and multiple aac audio channels. While opening the file in a browser reports at the top "audio append of xxxxxxx failed for segment #0 in playlist 0-480.m3u8". Nothing is obvious in the logs of the external decoder container. I tried to run the same command inside the container to produce a file and ffprobe on the produced file report:
Not detecting m3u8/hls with non standard extension and non standard mime type
Last message repeated 1 times
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x559e023ef640] Format mov,mp4,m4a,3gp,3g2,mj2 detected only with low score of 1, misdetection possible!
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x559e023ef640] moov atom not found
/tmp/Test.mp4: Invalid data found when processing input

In the past there were no problems with the same file, and also if I run inside the container a minimalized ffmpeg command it works without any problem.
this are the flags present in the original command used by memories after the input file path that are not working:
-copyts -fflags +genpts -vf "format=nv12|vaapi,hwupload,scale_vaapi=force_original_aspect_ratio=decrease:format=nv12" -map "0:v:0" "-c:v" h264_vaapi -global_quality 24 -map "0:a:0?" "-c:a" aac -start_number 0 -avoid_negative_ts disabled -f hls -hls_flags split_by_time -hls_time 3 -hls_segment_type mpegts -hls_segment_filename /tmp/go-vod/4e0r5b8m0i80-485858818/max-%06d.ts -force_key_frames "expr:gte(t,n_forced*3)" test_out.mp4

When I reduced to just this:
-copyts -fflags +genpts -vf "format=nv12|vaapi,hwupload,scale_vaapi=force_original_aspect_ratio=decrease:format=nv12" -map "0:v:0" "-c:v" h264_vaapi -global_quality 24 -map "0:a:0?" "-c:a" aac test_out.mp4
The output file has no problem, and ffprobe reports no issues.

Unfortunately, I am not an expert of all these hls flags used in ffmpeg, but I guess they cannot be used in files with more then 1 audio channel.

I also take the opportunity to thank you for the amazing memories app!
I hope this can be easily fixed.
Best

Steps To Reproduce

No response

Platform

- OS:Arch Linux
- Browser:Firefox
- Memories Version: 7.8.2
- Nextcloud Version:32.0.6 (nextcloud-aio)
- PHP Version:

Screenshots

No response

Additional context

• Any errors in the JS console?
• Any errors in the Nextcloud server logs?