чт, 4 июл. 2024 г., 02:39 Mark Filipak <markfilipak.i...@gmail.com>:
> H.264 appears to have made I- P- & B-frames obsolete. > > Everyone's probably seen my DTS-PTS diagrams. > > Closed GOP > PTS order I B B P B B P.. > / ______/ ______/ > / / / > DTS order I P B B P B B.. > > Open GOP > PTS order ..B B I B B P.. > ______/ ______/ > / / > DTS order ..I B B P B B.. > open Bs > > where the open Bs are actually part of the previous GOP. > > Well, H.264 references the past & future in the same way, but on a > picture-slice basis. There are > I-slices, P-slices, and B-slices. The way to visualize that is to imagine > that above the I- P- & > B-frames you can see the frame's slices. Imagine there are links for those > slices to past & future > slices in other frames, even 'crossing' an I-frame's PTS. > > Such a diagram would look like a spider web with many lines going every > which way from every frame. > > An IDR frame is an I-frame where the spider web is collapsed/missing on > its left (in the past) so > that no I-frame slices reference any slices in the past, and likewise for > all the P- & B-frames to > the I-frame's right. > > That effectively means there are only two types of frames: IDR and > non-IDR. That effectively > obsolutes P- & B-frames -- they no longer have any meaning. > > If I am wrong, please let me know. It's what I've sussed out from H.264, > but H.264 is not human > readable. > > --Mark. > I also noticed some new answers at https://github.com/mifi/lossless-cut/issues/126#issue-comment-box discussing -segment command line switch for ffmpeg for cutting mp4 video. https://github.com/mifi/lossless-cut/issues/126#issuecomment-2059432251 note that this only said to be working for mp4 container and not matroska. _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
