[FFmpeg-user] Why are these different?

[Paul B Mahol]

On Sun, Feb 11, 2024 at 8:50 PM Mark Filipak <markfilipak.imdb at gmail.com>
wrote:

> On 11/02/2024 14.28, Paul B Mahol wrote:
> > On Sun, Feb 11, 2024 at 7:12 PM Mark Filipak <markfilipak.imdb at gmail.com
> >
> > wrote:
> >
> >> On 11/02/2024 13.09, Bouke / Videotoolshed wrote:
> >>> So do you, so why ask the question?
> >>> Now go away!
> >>
> >> I do not know the answer.
> >>
> >
> > In most cases you will get in most times different results for those 2
> > variants.
>
> Help me to understand, Paul.
>
> If '-ss' precedes '-i', then one set of code is run, but if '-i' precedes
> '-ss', then a differing
> set of code is run.
>
> Is that statement correct?
>

Yes, such statement is correct.


>
> > Only for perfect containers and perfect implementations it will give same
> > result in every case.
>
> Well, I wish I knew how to test whether the M2TS that's on disc is a
> perfect stream, and if not, how
> to fix it before doing any trimming.
>

Real seeking (-ss before -i) in M2TS with libavformat is not always
frame-accurate.
Answering if it can be made frame-accurate is beyond my current knowledge.


>
> Aside: Though the actual source file is called 00305.m2ts, it appears to
> have only a program stream
> (PS); it does not contain a TS header. I checked other M2TS files on other
> discs. None of them
> actually have TSs.
>
> Regards,
> Mark.
>
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
>