[FFmpeg-devel] [PATCH v4 03/11] libavutil/hwcontext_d3d11va: adding more texture information to the D3D11 hwcontext API

[Artem Galin]

On Sat, 9 May 2020 at 22:29, Soft Works <softworkz at hotmail.com> wrote:

> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > Max Dmitrichenko
> > Sent: Saturday, May 9, 2020 10:42 PM
> > To: FFmpeg development discussions and patches <ffmpeg-
> > devel at ffmpeg.org>
> > Subject: Re: [FFmpeg-devel] [PATCH v4 03/11] libavutil/hwcontext_d3d11va:
> > adding more texture information to the D3D11 hwcontext API
> >
> > > You can document that wherever you want, but for existing users,
> > > command lines that have always been working before will stop working
> > > in a significant number of cases.
> > >
> > >
> > not sure where it goes:  if a user uses new version - there are new
> aspects to
> > consider
>
> Is that so?  Whether or not that is acceptable for ffmpeg is not up to me
> to decide, though. I'm just trying to illustrate the consequences.
>
>
> > > But still, even with your patch: What will happen when DX11 is not
> > > available?
> > >
> > > Will it
> > >
>
Please read the patch

> > > 1. fail?
>
Yes

> > > 2. or will it use D3D9 instead?
>
No automatic fallback to D3D9, D3D9 is selected by explicit command line
only

> > >
> > >
> > there should be no secrets here - implementation is available, do you see
> > fallback implementation?
>
> Yes, I'm seeing that indeed:
>
> Mark Thompson asked:
> >> > +    mfxIMPL          impl = MFX_IMPL_AUTO_ANY | MFX_IMPL_VIA_D3D11;
> >>
> >> Does that still do the right thing on systems where only D3D9 works?
>
yes, it works with DX9. This flag is mandatory only for DX11.

>
> You replied:
> > yes, it is only a hint for D11 when possible.
>
> I would understand 'when possible' in a way that D3D9 would be used
> 'when not possible'.
>
> If that's true, it means, that an ffmpeg user executing a command line
> cannot be sure whether D3D9 or DX11 will be used. That would mean
> that the behavior is not deterministic.
>
This is not true, it is your assumptions.
Behavior is deterministic:
DX11 by default.
DX9 if user selects it explicitly via command line.

>
> Regards,
> softworkz
>
>
>
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Regards,
Artem.