[mythtvnz] CPU required for Freeview HD

[Steven Ellis]

On 20/08/2008, at 2:27 PM, Barry Clearwater wrote:

> I take the point that a high def signal is getting heavily compressed,
> but we *are* talking about well known compression algorithms are we  
> not?
> Should somebody be writing a more optimised piece decompression  
> code, or
> in a lower level language? (cough - assembler anybody!!??)
> ITs just a 2D picture, our systems are capable of rendering 3D on the
> fly...
> I must be missing the point and over simplifying it somewhere.
> <pride speaking>
> No way should windows boxes out-compute a gnu/linux system.
> </pride>



The H264 decode flatlines all OSs if done in software due to the  
complexity of the decode when dealing with our broadcast streams.

I've compared Linux and Mac software decode on the same hardware,  
EyeTV vs MPlayer, and they appear to use similar amounts of CPU.

The best windows codec for software decode is CoreAVC which is a  
proprietary commercial codec.

Until we get a way to accelerate some of the decode on the GPU we are  
going to lag behind Windows users who have hardware accelerated decode  
via the main graphics card vendors.

As to STBs, as mentioned they have chips designed to accelerate the  
decode in hardware. If you have had a play with the Zinwell STB you  
would notice that it can get very hot due to the load.

Steve


Steven Ellis - Technical Director
OpenMedia Limited
email   - steven at openmedia.co.nz
website - http://www.openmedia.co.nz

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