Wine GPU decoding

[Henri Verbeet]

On 1 April 2014 15:50, Michael Müller <michael at fds-team.de> wrote:
>> Which APIs did you consider for this? What were the various issues?
>> What made you choose VAAPI in the end? Do you have tests for how the
>> dxva / d3d9 interface is supposed to work?
>
> I mostly considered VAAPI and VDPAU for this as they both offer support for
> multiple vendors.
>
> VDPAU has native support for nvidia, amd (only open source driver) and S3
> but not for intel. There is a OpenGL backend for VDPAU which can be used on
> Intel graphic cards but I expect the video decode engine of Intel to reach a
> better performance than an implementation which is completely based on
> OpenGL.
>
> VAAPI has native support for intel, crystal HD decoder, S3 and can also use
> VDPAU and the amds proprietary XvBA  interface. It simply supports
> everything VDPAU does plus Intel and the proprietary AMD driver. I think
> that a library which offers support for the most graphic cards is the best
> possible option for Wine as we do not want to implement these decoders
> multiple times.
>
I don't have a particularly strong preference for one or the other,
provided it works with the free drivers, but I was hoping for more of
an analysis of the actual APIs, and how well they fit with DXVA. That
does require figuring out all the D3D / DXVA interactions first, of
course. In terms of vendor support, if it comes down to it, I don't
think fglrx support is a very convincing argument, and I'm sure Intel
would happily accept patches for e.g. VDPAU support. Did you look into
OpenMAX at all?

> There are currently no tests so far. The reason for this is that mingw does
> not support the dxva header files and you can not use the hardware decoder
> in a VM. So I basically wrote some test code in MSVC and tested it on an old
> laptop which is running Windows 7 with a nvidia 9800 GTS.
>
> VLC wrote some header files for mingw which they use to cross compile VLC,
> but it does not offer everything we need (
> http://www.videolan.org/developers/vlc/modules/codec/avcodec/dxva2.c ).
> Maybe whe can use the wine header file or ship a more complete version to
> allow cross compiling.
>
I'm not sure how you're currently writing tests, but unless you have a
good reason not to, you probably should be using "make crosstest".