[mythtv-users] vdpau - more than just decoding?

[Raymond Wagner]

jansenj wrote:
> Just a random question:
>
> I know the new nvidia cores have the vdpau api now for faster decoding 
> of video streams.  I don't know enough about the api, but will we be 
> seeing the ability to transcode and even commercial scan in the future 
> for these cards (maybe distant future)?  Kind of like the badaboom 
> encoder?  Or is the CUDA api available for linux and make this sort of 
> thing available under linux?
VDPAU is nothing more than a hardware decoder.  There is indication that 
decoded 'textures' can be pulled back to the system after decoding, but 
something else will still have to be used for encoding.
> Then are all graphics cards series 8 and above created equal (put 
> build and component quality aside) when it comes to vdpau?  Or are 
> some going to run better than others for say 1080p mpeg2 or h264?  Is 
> 64bit 256MB VRAM enough for this application?  I'll never be doing 
> anything 3d with this card?
256MB cards used to cause problems decoding in MythTV, but I believe 
that has been resolved.  There are two variants of decoding on the 8+ 
series cards, the primary difference being hardware decoding of the VC1 
entropy coding.  Since driver revision 180.35, this has been supplanted 
with decoding that within the driver.  Whether than is done on the CPU 
or GPU, I don't know.  Deinterlace filters are run on the GPU, rather 
than the video decoder, and the x400 cards are too slow for the more 
complex filters.