Encoding input videos created by MS Teams corrupt output audio - unless PCM/copy

[Grobe]

Related thread regarding UI, but not same issue so hoping it's ok I make a new topic on this
gui warning (feature request)

Avidemux v2.8.2 (241212_ce994de41a6)

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Compiler: GCC 13.3.0
Build Target: Microsoft Windows (x86-64)
User Interface: Qt (5.15.15)
Operating System: Microsoft Windows (6.2.9200; 64-bit)
Time: Wed Jan 08 14:25:30 2025

0: C:\Users\keirg\tools\portable\avidemux_64\avidemux.exe

ffprobe output of the input video file (should give at least as detailed output as mediainfo, doesn't need any installing as it is pre-installed on my Linux Fedora KDE computer at home)

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$ ffprobe Grunnopplæring.mp4 -hide_banner
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Grunnopplæring.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2
    creation_time   : 2024-10-09T11:15:22.000000Z
  Duration: 01:47:04.64, start: 0.000000, bitrate: 424 kb/s
  Stream #0:0[0x2](eng): Video: h264 (libopenh264) (Baseline) (avc1 / 0x31637661), yuv420p(progressive), 1920x1080, 371 kb/s, 16 fps, 16 tbr, 10k tbn (default)
      Metadata:
        creation_time   : 2024-10-09T11:15:22.000000Z
        vendor_id       : [0][0][0][0]
  Stream #0:1[0x1](eng): Audio: aac (libfdk_aac) (mp4a / 0x6134706D), 16000 Hz, mono, s16, 51 kb/s (default)
      Metadata:
        creation_time   : 2024-10-09T11:15:22.000000Z
        vendor_id       : [0][0][0][0]

Different practical output tests to see what works and what does not work

• setContainer = MKV ; audioCodec = FDK_AAC ; Corrupted audo
• setContainer = MKV ; audioCodec = PCM ; Normal audible audo
• setContainer = MKV ; audioCodec = AC3 ; Error message, unable to continue
• setContainer = MKV ; audioCodec = Copy ; Normal audible audo

Error message when selecting AC3 audio format (cannot copy plain text in W11)
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Set of sample py files - file name indicate success or not (forum wouldn't allow me to upload the last one with pcm, but the cut time stamps where the same as the others)
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Edit: Idea about possible reason for this issue
Ok, so I just litterally did the ffprobe command a couple of minutes before I posted the thread. I now realize the audio bitrate of the original audio track is way lower (51 kb/s) than what I specified as output.
Can this be the sole cause of the issue I ran into ?

[eumagga0x2a]

The problem is likely related to audio track being Mono (and something not yet identified as monaural tracks I created locally work just fine). You might try enabling remixing to Stereo. Also please test the lavc (libavcodec) AAC encoder rather than that by FDK.