[FFmpeg-user] Please help with weird video problems

[Anatoly]

On Tue, 7 Feb 2023 22:00:35 +0300
Alexander Gribanov <sunrisecoder at gmail.com> wrote:

> Hello!
> 
> Here is a downloaded Facebook Livestream video which I'm trying to
> process:
> https://drive.google.com/file/d/1mVkQbzVSzhOlQbT2mB1J2yvPFV5kl5Dq/view?usp=share_link
> 
> I can play it correctly in MPC-HC Media Player Classic, but when I
> try to add this video to Adobe Premiere 2022, there around 3:00:00
> position audio is about 40 seconds ahead of video...
> 
> I tried to remux and re-encode this video using ffmpeg, it showed a
> lot of warnings like this:
> [aac @ 000001c1bfe68e40] env_facs_q 254 is invalid
> 
> I tried different options like "-vsync cfr", "-fps_mode drop" and some
> other stuff which I don't remember already, but nothing helped :( In
> MPC-HC it was ok, but in Adobe Premiere still 40-seconds a/v unsync.
> 
> I assume that the problem is with timestamps on the audio track.
> 
> I would like to make using ffmpeg just a simple cfr video 29.97 fps /
> audio 48kHz without any timestamp gaps and offsets.
> 
> Could anybody please help me to understand how to analyze and
> diagnose such problems in such videos to be sure what the exact
> problem is?
> 
> Could You please help me find the solution (i.e. options or
> subcommands to ffmpeg).
> 
> Thank You very much in advance :)

Maybe re-encode it with constant framerate using 'framerate' filter?
ffmpeg -i in.mp4 -vf framerate=fps=29.97 -c:a copy -c:v libx264 -b:v
800k out.mp4