Re: [FFmpeg-devel] [PATCH] avcodec/vvcdec: fix seeking for open GOP

[Nuo Mi <nuomi2021@gmail.com>]

On Sat, Feb 3, 2024 at 8:21 PM James Almer <jamrial@gmail.com> wrote:

> On 2/3/2024 9:17 AM, Nuo Mi wrote:
> > On Sat, Feb 3, 2024 at 7:54 PM James Almer <jamrial@gmail.com> wrote:
> >
> >> On 2/3/2024 7:34 AM, Nuo Mi wrote:
> >>> how to reproduce:
> >>> wget https://media.xiph.org/video/derf/y4m/students_cif.y4m
> >>> vvencapp --input students_cif.y4m --preset faster --output students.266
> >>> MP4Box -add students.266:fps=30000/1001:par=12:11 -new students.mp4
> >>
> >> Can't you do this with ffmpeg? mp4 muxing support was added recently,
> >> and we have a parser to find frame boundaries from raw bitstreams.
> >>
> >> Yes, we can
> > ffmpeg -i students.266 -c:v copy students.mp4
> > But the reporter used the mp4box
> > see:  https://github.com/ffvvc/FFmpeg/issues/190#issuecomment-1924169765
>
> That's ok, just wanted to know why not use ffmpeg for this. If it
> couldn't remux the file, then that'd be something we should fix.
>
Ts demux has an issue for both HEVC and VVC. If you use ffplay on a TS
file, you will see corrupted frames after a seek.
The main reason is that the demuxer does not send the key frame after a
seek; instead, it sends many frames before the key frame.
Not sure if it's a feature or a bug in the demuxer

you can reproduce it with
wget https://s3.amazonaws.com/x265.org/video/Tears_400_x265.mp4 && ffmpeg
-i Tears_400_x265.mp4 -c:v copy tos.ts
ffplay tos.ts

> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".