This is actually part of nVidia's VDPAU (Video Decode and Presentation for
Unix), which is an API that anyone can use to accelerate decoding.
There are some caveats to this..
The 8800 Ultra, GTS, and GTX only have VP1, same as the 5/6/7 series and are
not supported by VDPAU. Every other kind save for the 8400 has a GPU w/
"VP2".
The 8400 GS is the best 8-series card to use for video acceleration, and the
worst to use for 3D acceleration. This is the only VP3 GPU (save for some
IGP stuff).
The brand new GT200 series cards based on the GT215/216/218 are better yet
(G210, GT220, GT240) with VP4.
VP2 - Full H.264 acceleration, partial MPEG-1, MPEG-2, VC-1, WMV9
VP3 - Full acceleration for everything the VP2 cards can do partially, with
some caveats on widths for H.264
VP4 - VP3 + MPEG-4
GeForce 6 introduced some acceleration, but only through XvMC and only for a
few video types that you're not likely to be playing.
There would be a significant difference in CPU usage between say an 8400GS
and an 8800GS for decoding VC-1, with the 8400GS being the winner (and
available as cheap as $30 straight up!). The 210 cards are even better and
can be found as cheap as $30 after mail in rebate.. and they have the
advantage of a faster core clock and memory which would give better
theoretical desktop performance. The 210 also usually has HDMI/DVI/VGA
while the 8400s are usually DVI/VGA combos.
Phoronix did a test a while ago with an 8400GS doing video decoding with
IIRC a ~2GHz AMD single core with very low CPU usage, it wouldn't be
unreasonable to expect an underclocked/undervolted current gen CPU @ 800MHz
to be able to play even copy-protected HD video with an 8400GS or
G210/GT220/GT240. An Atom could really shine here, the Ion chipset is a 9400
+ VP3! There are also Atom boards with PCI-E x16 slots (ECS 945GCD-M comes
to mind).
As far as encoding, hopefully there will be a CUDA-accelerated encoder
(better yet would be OpenCL of course, but who knows what will be available
first? If it's CUDA you better have an nVidia card!) for Linux soon. If you
can record raw video, it shouldn't really matter how long it takes to
encode/compress as that can be done in the background. But you may find you
use less power with a faster 4-core processor (higher flop/watt efficiency
than a lower power CPU, so you max it out for a shorter time then it can
sit in an idle/low power state). But you don't NEED anything more than the
cheapest CPU you can find. Transcoding in real-time will take some real
processing power..
Disclaimer: My knowledge of encoders for Linux is extremely limited, there
may already be one that supports GPGPU acceleration for encoding.
-Frank
--------------------------------------------------
From: "Matthias" <[email protected]>
Sent: Wednesday, December 30, 2009 10:46 PM
To: <[email protected]>
Subject: Re: [mhvlug] Mythbuntu or Mythdora
I don't recall if it was mentioned but i believe one feature the new
release of myth supports is decoding of HD content on the gpu for nvidia
cards 8000 and up. From what I remember you can watch HD content on a
800 MHz processor with this option.
Matthias Johnson
Sent from my iPod
_______________________________________________
Mid-Hudson Valley Linux Users Group http://mhvlug.org
http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug
Upcoming Meetings (6pm - 8pm) MHVLS Auditorium
Dec 2 - MythTV
Jan 6 - Git
_______________________________________________
Mid-Hudson Valley Linux Users Group http://mhvlug.org
http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug
Upcoming Meetings (6pm - 8pm) MHVLS Auditorium
Dec 2 - MythTV
Jan 6 - Git
