If you just want a ffmpeg command, try
1 2 3 4 5 6 7 8 |
ffmpeg -i input.mov -i overlay.mov \ -filter_complex "[1:v]setpts=PTS-10/TB[a]; \ [0:v][a]overlay=enable=gte(t\,5):shortest=1[out]" \ -map [out] -map 0:a \ -c:v libx264 -crf 18 -pix_fmt yuv420p \ -c:a copy \ output.mov |
This starts the overlay at 5 seconds with the overlaid video start point being 00:15
.
setpts=PTS-10/TB
is setpts=PTS+(overlay_delay-video_trim_in)/TB
overlay=enable=gte(t\,5)
is overlay=enable=gte(t\,overlay_delay)