Concatenate mp4 files from AMB82-mini fails

Technical Discussion
1

I was attempting to concatenate a number of individual mp4 files recorded with AMB82-mini using ffmpeg. However, the operation failed with error ‘Invalid NAL size’. Is this a known limitation of the mp4 file structure used by AMB82-mini? Is there a quick way to combine the files? Thanks.

2

Hi @Barryn56,

I am able to concatenate 2 or more mp4 files via ffmpeg.

I am using this command ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "[0:v:0][1:v:0]concat=n=2:v=1:a=0[outv]" -map "[outv]" output.mp4.

For this command, I saved two mp4 files that consists only of video and no audio (using our Arduino example.)

There is probably a faster way which is to remux the mp4s to mpeg-ts and then concatenate using ffmpeg.

Thank you.

3

Thanks for the quick response, Kelvin - I shall try that out.
Barry