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

[Michael Koch]

Am 27.03.2020 um 10:29 schrieb Paul B Mahol:
> On 3/27/20, Michael Koch <astroelectronic at t-online.de> wrote:
>> 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.
>>
> Look at realtime filter.

That's not what the OP wanted. He 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."

Michael