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

[Michael Niedermayer]

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


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

The bravest are surely those who have the clearest vision
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notwithstanding go out to meet it. -- Thucydides
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