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

[Michael Koch]

Am 27.03.2020 um 10:10 schrieb Paul B Mahol:
> On 3/27/20, foxtail mega <foxtailmegadeveloper at gmail.com> wrote:
>> Actually I meant when ffmpeg is running, I want to send parameters to that
>> running ffmpeg instance and that should change the filter_complex overlay
>> parameters in the next frame of processing.
>>
>> Using expression is like hard coding parameters into ffmpeg command. I need
>> something where I can send the variable parameters when I need it without
>> stopping the current running ffmpeg command.
> Please stop top posting.
>
> There is sendcmd filter for this, but I think overlay filter does not
> support commands,
> but that could be easily fixed.

The overlay filter does already support commands. There is an example in 
chapter 2.61 of my book:
http://www.astro-electronic.de/FFmpeg_Book.pdf

But I think the question was if the parameters can be changed in 
real-time while ffmpeg is running. I don't know if this is possible.

Michael