[Open-graphics] Nvidia has 100% decode of h.264

[James Richard Tyrer]

Tim Schmidt wrote:
> On 4/29/07, Dieter <netbsd at sopwith.solgatos.com> wrote:
>> "H.264 offload is absolutely necessary for good Blu-ray/HD-DVD playback."
> 
> Exactly the situation when DVD on the PC premiered circa 1998.  Now,
> 10 years later, $60 motherboards that integrate graphics, audio,
> networking, all the regular motherboard stuff, and a CPU - again, for
> $60 - can decode a DVD in software without so much as a single dropped
> frame.  Anything more expensive does it with single digit CPU load.
> Hardware h.264 acceleration is an early-adopter problem.

Perhaps you are correct.  When we can buy a motherboard with 2 quad core 
CPUs running at 3 GHz, then decoding H.264 should be no problem. 
Actually, you will be able to do so in a few months but the price will 
be rather high.

But ... (tm)

The question is how much of the system's power will be required to do 
this.  If it takes over 50%, this is still going to slow down whatever 
else you are doing on your system.

So, no matter how powerful your PC (within reason) it is still going to 
be useful to have hardware that will do DCT/IDCT and YUV <> RGB 
conversion since such hardware will always be more efficient at doing 
these specialized tasks.  The same technology that makes the 2 X 4 CPU 
computer affordable will also allow 8x8 DCT/IDCT and YUV <> RGB with a 
latency of a few clocks (get it down to the theoretical minimum).  You 
should be able to get YUV <> RGB down to 3  clocks since it is a [3 
vector] * [3 x 3 matrix] + a [3 vector] -- 3 multipliers and 3 adders 
per color (you can do this today but it is too expensive).  Still 
haven't found my DSP text book so I don't know what the theoretical 
minimum would be for the DCT/IDCT

If wavelets become the standard method of compression then hardware that 
is good at performing a 2D FIR filter will be the next thing.

-- 
JRT