I have a full time old mp4 video and a newest video, I want to trim frames from old video, then merge new to old trimed to build a new full video, can I do it in one ffmpeg command without reencode?
Something like oldFull.mp4 – lastFrames) + new.mp4 = newFull,mp4
If old full frames are oldFrames, and want to remove last frames as removeFrames, how can I merge new.mp4 to OUT?

ffmpeg -i IN -c copy -bsf:v noise=drop=between(n,removeFrames,oldFrames) OUT