[FFmpeg-user] Way to encode and crop dynamically by keyboard

[Lou Logan]

On Tue, Jun 5, 2018, at 1:06 PM, David Barbassat wrote:
> Dear All, 
> 
> I am looking for a way to encode by ffmpeg a video but with a dynamic
> crop provided by shell variables 
> 
> For example is it possible to use ${x} and ${y} in the command line and
> change them during the encoding process without launch the encoding each
> time ? 
> 
> Like a crop motion :) 

Should be possible with the zmq filter:
https://ffmpeg.org/ffmpeg-filters.html#zmq_002c-azmq

crop supports the following commands usable by (a)zmq and (a)sendcmd:
https://ffmpeg.org/ffmpeg-filters.html#Commands-12