[FFmpeg-user] Is there a way to cut a video at an exact time ?

[bbb]

Sorry for bothering you. It only behaves like this when I use "-codec 
copy". Without that option it accepts the exact time I've specified.

On 4/13/24 13:47, bbb wrote:
> I want to cut off the start of a video. When I tell ffmpeg to start at 
> an exact time, it refuses to do so and instead starts at a time that's 
> somehow "convenient" for ffmpeg. I can only assume that it's probably 
> depending on something like a keyframe or an important frame for the 
> compression algorithm but I don't really know.
>
> the command:
> ffmpeg -ss 0:32.08 -i video.mkv -codec copy -map 0 video.cut.mkv
> makes the output start around 0:31 (even when I change the parameter 
> value a bit, the result is exactly the same).
>
> Is there a way to make ffmpeg start at the exact time that I specified?
> Does it maybe depend on the codec and would it help if I recode it 
> before cutting?
>
> It would be even better if I were able to start at a specific frame 
> number but I didn't find a parameter to set that. To set a frame 
> offset seems only possible when you're exporting to images.
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