[FFmpeg-user] Fwd: OBS and OBS Portable Recording Into Same File Simultaneously

Gyan Doshi ffmpeg at gyani.pro
Fri Jun 26 12:22:36 EEST 2020

On 26-06-2020 02:08 pm, Moritz Barsnick wrote:
> You could try to observe at which point ffmpeg detects the first errors
> (the showinfo filter will indicate the byte position ffmpeg is
> operating on), and from there remove blocks of 512, 1024, 2048 bytes,
> hoping that after removal of some of them, you hit a proper block
> again, and ffmpeg will no longer "lose sync" at that point, until again
> a later point in the file.

showinfo operates upon decoded frames. This inspection will have to be 
done at the container level using a forensic tool which can identify 
start and end of block structures in Matroska. This assumes that the two 
write operations didn't write on top of each other. One saving grace 
could be that OBS, like ffmpeg, flushes data to files in blocks of 256 
kB, although I don't know if this is the case.


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