[mythtv-users] mythtv-vid opengl and new nvidia card

[Mark Kendall]

On 10/1/07, gad at jetcom.org <gad at jetcom.org> wrote:
> Now that the mythtv-vid branch is in trunk, I'm interested in using
> the opengl renderer. This seems to fix a problem that I've had for a
> long time with my 16:10 display and interlacing/tearing. However my
> fx5200 doesn't have the ooomph to render the HD realtime.
>
> Being that 7xxx or 8xxx series nvidia cards can be obtained for less
> than $100, it seems to make sense to pick up one of these newer cards
> to replace the aging 5200.
>
> Does anyone have recommendations on which class/card?  Obviously I
> don't intend to spend $500 here, or get something too hot, bulky.
>
> Does anyone use the opengl renderer with HD streams?  What kind of
> horsepower does it require?

For reference, I use a passively cooled 7600GS.

I've just done a double check playing back a 1080i demo recording from
Canal+ at 1080i using the Interlaced opengl deinterlacer. Apart from
some stuttering if osd fade is enabled, it seems to cope perfectly
well (I'd challenge anyone to tell me that it doesn't match set-top
box  quality)

The 'Interlaced' deinterlacer is not demanding though and using
something like a 2x HW kernel deinterlacer will not work at this
resolution with this card.

It's also worth mentioning that playback with these settings is more
demanding than 1080p playback. The renderer is throwing out just as
many frames with the added burden of deinterlacing.

... and, also worth reminding anyone working with 60fps sources (ie
NTSC/ATSC) that my sources are 50fps - so you'll need an extra 20% of
grunt!

> Does the opengl renderer use less cpu processor time? Presummaly it
> would, although sometimes X takes quite a bit for no reason. I'd
> rather utilize my cores for more simultaneous commflagging, rather
> than playback :)

Unfortunately, and for reasons I've never quite worked out, the opengl
renderer uses more cpu than standard Xv output. I think it's down to
some memory juggling/alignment that the driver is doing before sending
textures to the card.

Regards

Mark