[FFmpeg-user] Framerate automatically increased while cropping

[Gyan Doshi]

On 2021-08-23 10:45 am, Adam Nielsen via ffmpeg-user wrote:
>> why is the framerate automatically changed here from 29.98 fps to 120
>> fps, and how can I prevent from this ?
>>
>>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 2508 kb/s, 29.98 fps, 120 tbr, 90k tbn, 2k tbc (default)
>  From what I can find, "tbr" is the target framerate the media is
> indicating it wants.  So ffmpeg is just respecting that value.
>
> I guess you could use the -r option to override this and force a
> specific framerate if you want something different?  Or you could fix
> the metadata in the source file to have the correct target framerate to
> begin with.

`-tbr` is the framerate required to retain the smallest interval between 
frames in the jnput.

You can add `-fpsmax 30` with v4.4 or newer. This will limit output rate 
to 30 if the input is higher else keep the original rate.

Regards,
Gyan