[Mesa-dev] 10bit HEVC decoding for RadeonSI

[Christian König]

Hi Peter,

Am 25.01.2017 um 19:45 schrieb Peter Frühberger:
>
>
>     Peter, Rainer any idea what I'm missing here? Do you guys use some
>     modified ffmpeg for Kodi or how does that work for you?
>
>
> do you set the format correctly, e.g.: 
> https://github.com/FernetMenta/kodi-agile/blob/master/xbmc/cores/VideoPlayer/DVDCodecs/Video/VAAPI.cpp#L2697 
> to create the surfaces?

Well the problem here is that the VA-API interface is not consistent and 
I'm not sure how to implement it correctly.

See your code for example:
> VASurfaceAttrib attribs[1], *attrib;
>
> attrib = attribs;
>
> attrib->flags = VA_SURFACE_ATTRIB_SETTABLE;
>
> attrib->type = VASurfaceAttribPixelFormat;
>
> attrib->value.type = VAGenericValueTypeInteger;
>
> attrib->value.value.i = VA_FOURCC_NV12;
>
>

First Kodi specifies that NV12 should be used which implies that this is 
a 8bit surface.

> // create surfaces
>
> VASurfaceID surfaces[32];
>
> unsigned int format = VA_RT_FORMAT_YUV420;
>
> if (m_config.profile == VAProfileHEVCMain10)
>
> format = VA_RT_FORMAT_YUV420_10BPP;
But then Kodi requests a 10bit surface. Now what is the correct thing to 
do here?

I can either create an NV12 surface, which would be 8bit but would 
result in either an error message or only 8bit dithering during decode.

Or I can promote the surface to 10bit, which would result in a P010 or 
rather P016 format.

Or and that is actually what I think would be best the VA-API driver 
should trow an error indicating that the application requested something 
impossible.

>
> afterwards we just do drm / egl interop, via:
> https://github.com/FernetMenta/kodi-agile/blob/master/xbmc/cores/VideoPlayer/DVDCodecs/Video/VAAPI.cpp#L1374 
>

I'm not sure if that will ever work correctly. The problem is that 
VA-API leaks to the application what the data layout in the surface is. 
As soon as we turn on tilling that will only work with rather crude hacks.

I will try to get it working, but probably need help from you guys as well.

Regards,
Christian.

> You need ffmpeg 3.2.
>
> If you use vaPutSurface it will end up as RGBA32 or something, which 
> is why we use the above way.
>
> Best regards
> Peter
>
>
>     Cheers,
>     Christian.
>
>
>
>
>
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