I'm trying to cut a video (a debate on TV) with ffmpeg without re-encoding, and I need to cut between 2 sentences a guy pronounce. I think the precise moment is between two keyframes, because whatever the timestamp I try to cut at, I always get too much sound (and video) or too few. Here is my ffmpeg command line :
ffmpeg -i video.mp4 -ss 0:0:0.9 -vcodec copy -acodec copy videoB.mp4 -y
I'm aware that the position of the -ss option in the command line matters : here, it is supposed to give me all the accuracy ffmpeg can offer. I know I'm probably trying to cut my video neither on a I frame, nor on P or B frames.
So is there a way to get the closest (P or B) frame, doing some calculations with the preceding I frame to generate a new I frame, then start the video with this brand new I frame and no sound, until the correct timestamp is reached. Then the video could go on normally.
I really don't want to bother me with re-encoding (which is an use of ffmpeg I don't master on command line). I'm using ffmpeg version 2.5.8-0ubuntu0.15.04.1.