[mythtv-users] CPU for a frontend

[William Powers]

On Sun, Feb 26, 2012 at 10:16 AM, dave cunningham <ml at upsilon.org.uk> wrote:

> Thanks, this is useful information.
>
>  From reading the board over the last while I have the impression that
> quality wise NVidia + VDPAU is still quite a bit ahead of the rest
> (de-interlacing quality, refresh rates, EDID support, general
> stability).
>
> This is the sole reason I am planning to use the GT430. Is this still
> the case? If I can avoid the discrete card then I will be glad to do so.
> (FYI WAF is probably the most important factor here).

Well, I'll tell you what I know and what I don't know.  In terms of
general stability, I would say NVidia + VDPAU is probably still ahead.
 In order to get OpenGL playback working on Intel HD Graphics I had to
patch and recompile the mesa RPM's.  I had never remade rpm's from
source before; I'm more familiar with patching and recompiling the
original tar ball.  Still, it only took me about 30 minutes, following
instructions I found on this list and by Googling.  The distros are
already starting to pick up that patch and so a recompile may no
longer be required.  It's been a couple of years since I had to patch
things to get VDPAU to work, so it's probably a fair statement to say
that Intel graphics support for Myth is somewhat less stable at this
point.  Still, once I got the capability working, it has been rock
solid for me.

I'm probably not the best person to ask about deinterlacers because,
for the life of me, I can't see any difference between VDPAU
Advanced,2x and VDPAU Temporal,2x.  It's been reported on this list
that basketball is a good example so I recorded a Syracuse game in
1080i a couple weeks ago and watched various portions of it using both
deinterlacers.  After all of that I still couldn't see any difference
on my 55" Sony and the only definite conclusion I came to is that I'd
rather watch basketball in 720p.

I did a fairly extensive evaluation of the OpenGL hardware-assisted
deinterlacers and I really didn't like any of them.  Linear blend
(2x,HW) is the only one that didn't stutter with a G620 but I didn't
like the results.  Kernel (2x,HW) stuttered with a G620 but worked ok
with an i3-2105.  The results were better but still not as good as I
was used to with VDPAU Temporal,2x.  Interlaced (2x,HW) didn't work
for me at all and Yadif (2x,HW) turned everything into green blobs.

Since I wasn't happy with the OpenGL deinterlacers, I tried the
software deinterlacers and,GreedyHighMotion,2x produced results that
look to my untrained eye as good as VDPAU Temporal,2x.  It does take a
fair amount of CPU:  The G620's run ~ 50% CPU while displaying 1080i
content, but there is no glitching and plenty of margin.

Some people prefer the GT430 for its audio over HDMI bitstreaming
capabilities.  I have read that Intel HD Graphics supports
bitstreaming as well but my system only supports 5.1 audio so all I
can personally vouch for is that 5.1 audio over HDMI works for me with
Intel HD Graphics.

I can't speak to EDID - I wasn't even aware there was a connection.

One could, of course, try Intel HD Graphics and, if you're less than
completely happy with it, it's easy to fall back on the GT430 and
VDPUA.