The task is to apply a customized watermark to a user when downloading content (samename why).
There are nuances:
— apply as quickly as possible on video file (say 5 seconds starting from the N-th)
not reconverting video is processed (an important factor for time while putting the video file and used resources to reconvert)
From I read of the manuals should be that ffmpeg and mplayer do not know how.
There are more options quick overlay vatermarki the video file at the moment of impact?