[FFmpeg-user] Hello. Gurus. Regarding PNG image overlay with alpha transparency change

[Lee Mitchell]

Hi. Paul.

 Sorry for the late reply since it verified just now
that working with '-loop 1 -i input_png' right in front filter_complex param
by your reminder. Thanks.

Have a nice rest of the day, Paul.


2024년 6월 7일 (금) 오후 12:54, Lee Mitchell <npdmailing at gmail.com>님이 작성:

> Hi.
>
> What I know is alpha change for another video clip pon base video like as
> "-filter_complex
> "[1:v]geq=r='r(X,Y)':a='if(between(t,0,9),alpha(X,Y)*(T/9),0)'[alpha];"
> which works very well as time goes by.
>
> But it is not working for a PNG image file as time goes by. It only sets
> alpha when the overlay starts which does not change while playing.
> How to change PNG alpha by base video clip's time?
> Could you guys advise me or hint me on keywords?
>
> Thank you in advance.
>