[mythtv-users] New Computer Advice

[Anthony Spinoza]

--- john roberts <homepagez at lycos.com> wrote:
> 
> I'm driving a Samsung 50inch DLP - which is a
> Progress Scan display running 1280x760 (If my memory
> is correct).
> 
> The Myth box is a Gentoo box with:
> 
> - 2.6.7 kernel
> - Latest Chris Kennedy patches for IVTV (0.10.x)
> - Latest nVidia drivers (6106)
> - Latest (stock) mythtv (0.15.1)
> - Running the XvMC performance patch from Daniel)
> - P4/HT 2.6G 800 FSB
> - two 160G drives
> - PVR-250
> - pcHDTV card
> - FX5500 video card

Very similar to my setup, minus the PVR-250 and the
XvMC performance patch. ( it's the only one of
Daniel's patches I didn't install. )

> Things look great for me as well.  But I get some
> studder when I first change the channel (ATSC we're
> talking here).  I also get some studder when I hit
> "i" to find out what I'm watching/etc.

Exactly what my system does, what is your CPU usage?,
use "xosview" or something similar, when an OSD is on
the screen, and what it is not? I am not at 100% CPU,
and I can't imagine a 2.6P4 would be either. I don't
believe these problems are related to CPU speed.

in mplayer I can play a 1080i stream with around 40%
CPU usage with "ffmpeg12mc"

> Nothing worked well without XvMC enabled.  So -
> after recompiling with march=pentium4 and with XvMC
> enabled - things were much better.

Same here, compiled with march=athlon-xp

> I would say the system is "usable/watchable" right
> now.  I think I have things pretty tweaked out for
> performance.  I'm running a very thin X window Mgr
> (can't think of the name of it right now) and I have
> enabled the 4k kernel stack option to help with
> performance.

hmmmm, I'm just running Gnome, and I haven't compiled
back to 4k stacks since the latest Nvidia driver which
fixed that issue came out. I'm going to try that, see
if it makes a difference.

> So - as I said - the PVR-250 running NTSC was not an
> issue... the CPU was over-kill as many have said
> here in this thread.  It was when I moved to ATSC
> (720p/1080i) content where my CPU had an issue.
> 
> Just my experience...

Are you driving the Samsung with 1080i timings, or
720p timings. I find that scaling causes lots of
studder, even though it's Xv scaling (probably taking
up bandwidth XvMC could use), if you match the ATSC
mode with the HDTV mode, and let the TV do the work
things are much happier. There is a patch someone
wrote that allows this with multiple modes.

How do you like DLP technology? ;)

-vito




		
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