[mythtv-users] How to minimize CPU usage

[Kevin Kuphal]

Jerry Rubinow wrote:
> I would think that the GPU on the video card is being used for the
> heavy lifting of decompression, as you say.  But is the buffer holding
> the output of those calculations on the video card or system RAM?  And
> if it is on the video card, does it have to travel back to the system
> first before being sent to the video card's output buffer, or does it
> go directly there without traveling back and forth over the bus first?
>
> I would guess for the first question that the GPU only operates on
> memory on the video card.  For the second question, it depends on how
> sophisticated the code is and the algorithm.
It seems to me after thinking about it that it has to go:

HDTV caputre (MPEG-2) -> disk (MPEG-2) -> MythTV (MPEG-2) -> XvMC 
libraries (MPEG-2) -> hardware GPU (MPEG-2) to video buffer (raw)

It would seem illogical that anywhere in the chain are the MPEG-2 frames 
decoded by the application or the libraries because XvMC offloads this 
decoding to the GPU.

In that case, the load on the PCI bus from disk to card should be the 
same as from capture card to disk and we within the specifications of PCI.

Kevin