.mov file with blank in it

[Bobi]

Hi people,

first of all, thanks to you for the work you put in this software program.

I use Avidemux 2.8.1 Release. Sorry if it is not the right place to post this message (I know I am in Main version 2.6 topic, but I did not know where to post this).

My problem is with the .mov file I link here:
https://drive.google.com/file/d/1yHISF3ekMDxve-XPtXQUfDwLT57kYUAc/view?usp=sharing

I generated using Avidemux MOV muxer.
When I open the file in Avidemux: it reads as I intended it to read it.
When I open the file VLC media player, it starts the same way, but between the seconds '2' and '3', there is a blank. No sound. Then the file is read correctly.
When I open the file in Windows Media Player, the sound is not synchronized at all with the image.

Do you people know what is going on ? Is it something worth to say to you, or because the .mov is read correctly in Avidemux, it does not concern you ? My concern is that I might share videos with people who do not have Avidemux on their machine, and so they will have a degraded version of the video.

To provide a bit of context of how I generated the .mov file:
I play the guitar and record myself with a microphone and audacity: I have a .wav file.
At the same time, I filmed myself with a webcam: I have a .mp4 file.
   
I load the mp4 file in Avidemux, and I replace the audio: Audio ==> Select Track ==> I replace Track 1 with a .wav file.
I synchronize the .wav music with the video, by tickling the "Shift" box, and typing in let's say +9200ms
I extract only a subpart of the video using the A and B marker.
I save the file as a .mov using the MOV Muxer.


Thanks for your time
Please tell me if I can do something so you can help me better.

[Elstar`]

Well, it works in MPC-HC (K-Lite codec pack) on Windows, but you can try to save in more compatible format, for example audio as AAC in mp4 container, then try playing the results.

And there is indeed no sound, but between seconds 0 and 1.591

[Bobi]

Hi,

I am not sure if I understood correctly what you proposed:
"Well, it works in MPC-HC (K-Lite codec pack) on Windows"
->
So it is stuff that I could download for instance from here: https://codecguide.com/download_kl.htm
to help me read this stuff ? But I am afraid that it is too complicated to expect this from people when I share the video.

"but you can try to save in more compatible format, for example audio as AAC in mp4 container, then try playing the results."
->
I opened the .mov file in avidemux, and tried to export it as mp4 (using MP4 Muxer): is this what you suggested ?
I got the following error: see screenshot.


"And there is indeed no sound, but between seconds 0 and 1.591"
->
Well, indeed I do not start playing right away. This "no sound" is normal, but what surprises me is that when I read the file using VLC, the sound "jitters", it stops between 2 and 3 secondes.

Thanks for your time

[eumagga0x2a]

Oops, thank you for the sample, current Avidemux nightlies got the number of channels wrong. This bug (regression?) is fixed now, the fix will be available in future builds.

The only video player on my system which seems to be able to handle edit lists (the QuickTime container feature Avidemux is using to delay too short audio) in an actually useful way, is the ffplay tool from FFmpeg: it skips right to the start of audio. Other players begin to play from the start of the video and fail, which is depressing. I can only recommend either to skip the silent part (i.e. start saving from the moment audio is present) or to add silence to the start of audio e.g. in Audacity before importing external audio track in Avidemux.

I opened the .mov file in avidemux, and tried to export it as mp4 (using MP4 Muxer): is this what you suggested ?

WAV (LPCM) audio, fully legal in MOV, is not allowed in MP4 (many camera manufacturers ignore that). "Elstar`" meant re-encoding the audio track to AAC, which is compatible with both. When using Avidemux built from the latest git (don't try nightlies from before Sep 8 2024, they don't have the number of channels fix), this indeed results in a file where video and audio have roughly identical duration which masks the issues many players have with edit lists.