[mpeg2] Re: Fw: hello

[Warren Young <warren@etr-usa.com>]

Mark Cuss wrote:
> 
> the Radeon's MPEG2 encoding on the fly ability is what one might call
> "hardware assisted" 

I suppose it's possible, but I have been unable to find out what,
precisely, is meant by "hardware assistance".  It could be as little as
converting the video data to 4:2:0 format, or as complicated as things
like computing motion estimation vectors.

> I have a Radeon in my PC at home
> (a Pentium II 400), and I am able to encode full frame rate 640x480 with
> very few dropped frames.  

Is that full IPB video?  I've done a number of tests of this board on
multiple machines, and I haven't ever approached full IPB VGA-size
encoding on such a slow box.

> However, my experience with software encoders on
> my work test machine (a loaded PIII 1 GHz) is that I can only get 2 or 3
> frames a second at the most at 640x480.

The ATI encoder is quite good, given its price and speed, but if you
study its output carefully, it's obviously got several limitations.  I
think these stem from intentional optimizations favoring speed over
correctness.  Those software encoders you're using are favoring
correctness over speed.

Consider Ligos's encoders: they have at least three different encoders
(not counting variations like CQ, VBR and CBR modes within a single
encoder), each with different characteristics.  One of these is a
real-time encoder, but Ligos hasn't replaced their other two encoders'
engines with this real-time engine.

> This indication would help confirm my previous thoughts on the Radeon
> having "hardware assisted" compression...  I will try to find some more
> information if anyone is interested....

Well, I'd be glad to know what "hardware assistance" means, exactly.  I
would put that info in my AIW Radeon review.  (See link below.)
-- 
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