DXVA2 Deinterlacing

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With the addition of DXVA2 decoding is there any chance that DXVA2 
deinterlacing could also be added? Hardware deinterlacing in the video decoder 
is very appealing, but I don't have an NVIDIA GPU.

Original issue reported on code.google.com by mikegros...@gmail.com on 17 Feb 2012 at 12:27

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This is not viable because its too slow on anything but NVIDIA.

Original comment by h.lepp...@gmail.com on 17 Feb 2012 at 8:10

• Changed state: WontFix

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I'm not sure that's true. MadVR does DXVA2 deinterlacing on ATI cards in 
realtime. Obviously it's not also decoding the video on the GPU, but does it 
really make such a big difference; or is there some other reason it would be 
slower in lavfilters than madVR?

Original comment by mikegros...@gmail.com on 17 Feb 2012 at 3:06

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madVR does not require to copy the image back from the GPU to system memory, 
which is the slow part.

Original comment by h.lepp...@gmail.com on 17 Feb 2012 at 3:29

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That makes sense; what about the native DXVA2 that's being worked on, which as 
I understand it omits the copy back?

Original comment by mikegros...@gmail.com on 17 Feb 2012 at 6:37

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Sure, but whats the point of adding deinterlacing there?
The native DXVA only works with EVR based renderers to begin with, and in that 
case the renderer will perform the same hardware based deinterlacing.

Original comment by h.lepp...@gmail.com on 18 Feb 2012 at 12:35

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Ideally the deinterlacing would work when used in avisynth for encoding. That 
is to say one could use lav video decoder in a graph, then use 
DirectShowSource(graph) in a script and get hardware accelerated deinterlacing 
(and decoding I suppose).

I've never seen an avisynth filter that uses DXVA2 for any video processing, so 
maybe it's not possible. I've also never written a DirectShow filter either, 
much less one that uses DXVA2, so I don't really know how feasible it is. 
http://msdn.microsoft.com/en-us/library/windows/desktop/cc307941.aspx just 
piqued my interest because of this paragraph:

"In DXVA 1, the software decoder must access the API through the video 
renderer. There is no way to use the DXVA 1 API without calling into the video 
renderer. This limitation has been removed with DXVA 2. Using DXVA 2, the host 
decoder (or any application) can access the API directly, through the 
IDirectXVideoDecoderService interface."

Of course that only mentions the VideoDecoderService, not the 
VideoProcessorService. So if it won't work without a renderer, then I agree 
there's not much point; just let the renderer deinterlace. If it could work 
without the renderer though, then I definitely think it would be worth 
implementing.

Original comment by mikegros...@gmail.com on 18 Feb 2012 at 5:31

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Of course its possible, but like i said its just too slow on AMD.

Original comment by h.lepp...@gmail.com on 18 Feb 2012 at 6:53

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Well realtime playback doesn't really matter for encoding. It just has to be 
faster than software deinterlacing, and getting the same results as hardware 
deinterlacing with software can mean performance as bad as a few fps currently. 
So the feature definitely still has some value even if it's slow.

Original comment by mikegros...@gmail.com on 19 Feb 2012 at 4:03

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With AMD it would be 3-5 fps, if even that fast.
For that, its not worth doing.

Original comment by h.lepp...@gmail.com on 19 Feb 2012 at 10:26