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

[Soft Works]

> -----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
> >
> > 1. fail?
> > 2. or will it use D3D9 instead?
> >
> >
> 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?

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.

Regards,
softworkz