Cannot append video files together to MP4 due to unsupported audio tracks

[Shooter71]

I have used multiple versions of avidemux successfully for the past few years to append MP4 video clips together using the Video Output - Copy, Audio Output - Copy, and Output Format - MP4v2 Muxer in v2.7.1, or just MP4 Muxer in later versions. I have been using the same video camera and video format for the MP4 file types and never had any issues/pop-up messages when trying to save the combined file. I believe started when I upgraded to v2.7.5, I started receiving a message (see 2.7.5 Pop-Up image) where there was a question about the video using non-IDR recovery points.  I did not understand what the issue was really about so I just said "Yes" and continue to combine the file. I have checked my combined files before and after the point of where the files were combined and  video/audio were still in sync so I just continued to combine videos this way. Recently, I tried to combine a couple of recent video clips all made from the same camera, and not the combined video will not play at all.  I updated to v2.8.1 and using the same video clips, I get a different error (see image 2.8.1 Pop-Up) of unsupported audio tracks and it will not let me continue to combine the video clips. I have downloaded back to vers 2.7.1 and tried combine the same video clips and get the same unsupported audio track error.  Any suggestions on what may be causing my issues? I have used Avidemux for a number of years without any problems of combining files and now I cannot combine any.

[szlldm]

The non-IDR recovery points warning is not about "video/audio were still in sync", but that there might be video corruption around the cut in the output video (this only applies when using Copy mode).

The error message simply tells, that the selected output container (in this case MP4) cannot accept the audio format that is in the source video. Your options are: 1) select a different container (preferably MKV), or 2) re-encode the audio (eg. change Copy to some of the listed codec (AAC, AC3, ...))

[therube]

back to vers 2.7.1 and tried combine the same video clips and get the same unsupported audio track error.

In what format is the audio of the source files?
And while you're there, in what format is the video of the source files?

[Shooter71]

I used mediainfo to pull in believe the requested information. Audio is in PCM and Video is AVC if I am reading this correctly.  I am still interested in why this worked well for years and using all the same camera and recording settings it is not working now.



(Unrelated but I did not receives notification of replies even though I checked that box on my post so apologize in the delay - maybe there is something else I need to do to get this to work)

[Shooter71]

The error message simply tells, that the selected output container (in this case MP4) cannot accept the audio format that is in the source video. Your options are: 1) select a different container (preferably MKV), or 2) re-encode the audio (eg. change Copy to some of the listed codec (AAC, AC3, ...))

Back in an older version, I know I had to use MP4v2 Muxer vs just the MP4 output format to get my joined clips to combine correctly.  The new version just has a single MP4 version and for the most part it was working ok as far I could tell except lately file types that it combined fine will not combine at all; did not notice any corruption mode but I guess I never specifically looked at just the cut areas. Anyway, I am not that familiar with MKV format as I generally understand MP4 to be the most universal so that is why I was staying with that format.  In my other reply with the audio format being PCM, does that help explain what may have changed on how PCM is handled in the software vs that past? I don't believe my Sony camera give me an option to change the audio record format.

[szlldm]

Probably in the past there was no compatibility check, so it just allowed incompatible audio track (e.g. PCM) into MP4.
You can re-encode audio track, by selecting an audio output other than "Copy" (one of the listed: AAC, AC3, etc.).

[eumagga0x2a]

Some old 2.7.x Avidemux versions silently output MOV format with mp4 filename extension when they encountered an (L)PCM audio track. In current versions, please select the MOV muxer explicitly. (L)PCM is illegal in MP4, but Sony doesn't care.

[Shooter71]

Thank you szlldm and eumagga0x2a for the responses. For my further knowledge, would you be able to clarify any understanding you have about incompatibility of PCM in MP4? The Sony 4K video camera output file container is MP4 and within that container they are using AVC video format and PCM audio format as can be seen in my image in Response #3. Therefore, it is not clear why PCM is considered incompatible to MP4. I can understand eumagga0x2a if it illegal to use PCM in MP4 without an appropriate license, but that seems more an a license issue vs incompatibility issue.

At the end of the day, my goal has always been to join my Sony MP4 video clips together into a single video clip without any transcoding to keep the combined video as highest quality as possible. I understand generally transcoding into different formats and can have some quality loss and takes longer time. Therefore, Avidemux was always the fastest and easiest way to join my video clips like they were all shot in a single recording.

[eumagga0x2a]

"Illegal" in sense of "not covered by technical specification" and therefore not supported by the FFmpeg library (libavformat) which does all the magic writing ISO (MP4/MOV), Matroska and MPEG-TS/PS containers in Avidemux.

No laws have been harmed in this post ;-)

[therube]

I understand generally transcoding into different formats and can have some quality loss and takes longer time.

You are speaking of transcoding using a different audio or video codec.

Moving between containers; like between mp4 & mov (& assuming the codecs are supported between each) would be lossless.

So, if with older versions you were saving as ".mp4" (& where presumably it was only .mp4 in name), actually saving as .mov, now, & assuming it works, specifically saving now as .mov, should not affect anything at all. (Of course you'll want to verify that.)


That said, I guess you need to take a look at "XAVC".
https://www.divergentmedia.com/blog/understand-xavc/
https://videoconverter.wondershare.com/convert-hd-3d/avchd-vs-mp4.html

So it seems, with Sony, with XAVC, a .mp4 container can contain LPCM audio.