Re:LosslessCut: lossless video/audio editing
by Gordonjcp on Tuesday December 13, 2022 @12:25PM
(#33972215)
You can't do that at all in long-GOP formats without re-encoding.
What happens is that every so often it sends a complete image - the intra frame - and then sends differences to show what changes from frame to frame. This is a complete and utter pain in the tits to edit with, so most people transcode to an intraframe codec like DNxHR or ProRes although there's absolutely nothing wrong with MJPEG or MPEG2 intra-only.
If you don't re-encode, you're limited to cutting at an intra frame because that's where it starts drawing from. If you don't you get all this weird "ghost trail" stuff happening.
What happens is that every so often it sends a complete image - the intra frame - and then sends differences to show what changes from frame to frame. This is a complete and utter pain in the tits to edit with, so most people transcode to an intraframe codec like DNxHR or ProRes although there's absolutely nothing wrong with MJPEG or MPEG2 intra-only.
If you don't re-encode, you're limited to cutting at an intra frame because that's where it starts drawing from. If you don't you get all this weird "ghost trail" stuff happening.