[FFmpeg-user] ffmpeg -i reports a video of length 03:17.53, but splitting into frames at 2 fps only results in one frame

Gyan ffmpeg at gyani.pro
Tue Jul 16 21:59:59 EEST 2019

On 17-07-2019 12:08 AM, Stéphane Chauveau wrote:
> It seems that the pts value depends of the stream time_base so the 
> formula 'N*30' is probably not valid in the general case.
> So if FR is not available in you meg file then I propose the following:
> Find the time_base value with
> ffprobe -hide_banner -show_streams -select_streams v  input.mpg | grep 
> time_base
> For example, that could be 1/1000
> Then use the formula 'N/(30*(1/1000))' assuming fps=30 and 
> time_base=1/1000
> If you get the right formula then the frame n=30 should have 
> pts_time=1.00  in the showinfo dump.

The constant TB is available, so to retime the stream as a 30 fps 
stream, it would be

     -vf setpts=N/30/TB

If a framerate value has been set then

     -vf setpts=N/FR/TB


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