[mythtv-users] Any advantage to compiling with XvMC?

[Jarod C. Wilson]

On Friday, Sep 12, 2003, at 06:42 US/Pacific, Joseph A. Caputo wrote:
>> On Thursday, Sep 11, 2003, at 03:25 US/Pacific, Steven Sartorius 
>> wrote:
>>
>>> Are there any advantages to compiling mythtv with support for XvMC?
>>> There
>>> was a blurb about this on the web site the other day but no real 
>>> info.
>>>  What
>>> exactly does XvMC do?  I've got a GeForce 4 MX and the libXvMCNVIDIA
>>> library....

>> Jarod wrote:
>> XvMC = X-video Motion Compensation.
>>
>> There's a section on it in nVidia's readme for their Linux drivers.
>
> Yes, I understand *what* it is, but what does it mean for Myth?  How 
> will it
> affect my picture quality/CPU load?  Is Myth offloading some 
> processing to
> my GF4MX, or is it merely an output enhancement that I couldn't get 
> before?
> Sorry if this questions seems stupid, but I've never seen any 
> explanation of
> just *how* Myth uses XvMC to its benefit.
>
> -JAC

Sorry, I thought the question was primarily asking what XvMC was/does, 
which is pretty self-explanatory from X-video Motion Compensation. With 
that understanding already in hand, I'm afraid I don't know exactly how 
much benefit you'll see from Myth compiled to use XvMC, as far as 
picture quality and CPU load.

My assumption is that it is primarily an output enhancement, but one 
that is done mostly in hardware, so it requires very little extra CPU 
(if any) and provides a definite improvement in video quality, reducing 
the ghosting effects some people see in high-motion scenes. Not sure if 
it would also help w/stock ticker jitter...

As always, someone please correct me if I'm way off my rocker. I 
haven't actually tried it out myself just yet, either...

Oh, and remember that only the GF4MX and GF4FX cards support the full 
range of XvMC capabilities provided by the nVidia driver. The GF4Ti 
cards only support parts of it.

--Jarod