[FFmpeg-user] How to change overlay parameter at runtime

Gyan Doshi ffmpeg at gyani.pro
Fri Mar 27 14:59:33 EET 2020

On 27-03-2020 03:37 pm, foxtail mega wrote:
> Clarification regarding information (x,y for overlay filter).
> I am using ffmpeg for mobile devices so i am using flutter-ffmpeg. Now
> i am using dart language for supplying x and y co-ordinates to ffmpeg
> instance. Issue is, after i run the ffmpeg command, there is no way i
> am able to change the coordinates, so i have to stop running ffmpeg
> instance, and then re-run ffmpeg with changed coordinates.
> I guess i will check for suggested solution of realtime filter and
> sendcmd. I am not sure if that would work though.

realtime filter is irrelevant here since you're using -re.  sendcmd 
parses its argument once at init, so can't be used to add or change 

What you can do is send directives to ffmpeg via stdin. One of the 
directives is 'c' to send commands to filters which support commands. 
While running ffmpeg, press ? to see list and syntax of available 


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