[FFmpeg-devel] [PATCH] nvenc: Compensate for hardware trying to mess with aspect ratio of DVD content.

[Michael Niedermayer]

On Sun, Jan 18, 2015 at 01:28:36PM +0000, Kieran Kunhya wrote:
> On 18 January 2015 at 12:22, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Sun, Jan 18, 2015 at 02:52:59AM +0100, Hendrik Leppkes wrote:
> >> On Sun, Jan 18, 2015 at 1:02 AM, Nicolas George <george at nsup.org> wrote:
> >>
> >> > L'octidi 28 nivôse, an CCXXIII, Kieran Kunhya a écrit :
> >> > > Oops I misunderstood, you mean the software must comply with the users
> >> > wishes.
> >> >
> >> > Yes.
> >> >
> >> > > Anyway my argument is that BT601 should be the default for the these
> >> > > resolutions.
> >> >
> >> > If you want, but that must happen immediately when the contents enters into
> >> > FFmpeg's data structure, not at a random point in the processing chain.
> >> >
> >> >
> >> Without arguing for or against BT.601 behaviour...
> >>
> >> nvenc should behave the same as libx264, or any other video encoder, if
> >> this patch makes it do that, then it should be applied.
> >
> > Yes, and AFAICS an earlier mail from philip indicates this is the case
> > "
> >     Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 720x576
> >     [SAR 64:45 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
> >
> >     With libx264, I get the same SAR and DAR out.
> >
> >     With nvenc, I get:
> >
> >     sample_aspect_ratio=16:11
> >     display_aspect_ratio=20:11
> > "
> >
> > In above example the user asks for a NON BT.601 format 720x576 at
> > SAR 64:45 and a DAR related to 720x576 NOT 702 or 704x576 of 16:9
> > yet nvenc gives her something else
> 
> Here's the point where I give up and start my own fork where things
> are done properly.

please elaborate about where you disagree

I think theres a misunderstanding between people on what some of the
aspect ratios mean and what they refer to

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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