[mythtv-users] HDTV performance in 0.18

Pete Buelow pete at putzin.net
Tue Apr 19 03:07:22 UTC 2005

David Wood wrote:

> Does anyone find it strange to not have enough horsepower to render 
> HDTV in 0.18 on an Athlon XP 3000+ with 1GB of RAM? (Caveat: this is 
> rendering to 800x600 24-bit S-Video on an fx5200.) XV and OpenGL work, 
> renderaccel is true, AGP functional, and by the way, xine can play 
> HDTV with Xv no problem.
> I'm using libmpeg2 and suid/realtime, and the system can just _barely_ 
> handle it without deinterlacing. It's pegged at 95% CPU, and still 
> drops occasional frames. If I turn on deinterlacing, then it's real 
> bad, dropping frames every few seconds.
> As before, toggling libmpeg, realtime, and opengl appear to have zero 
> effect on performance, despite log output from the frontend suggesting 
> they're working.
> I keep finding references to people who are doing HDTV with 2100's and 
> 2400's and so forth. I wonder what the difference is - rendering to a 
> different screen resolution or color depth perhaps?
> Saving grace is that in 0.18 XvMC finally works, almost. I still get 
> ugly flicker and stutter from the OSD, and so far am averaging about 1 
> hard-lock (reboot required) per day... A major improvement.
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>mythtv-users at mythtv.org
I've found that libmpeg doesn't do much good if you're using Xv, but it 
does suck CPU (you said doesn't change much, but it was about 5-10% on 
mine). Other things like making sure AGP 4x or 8x is enabled, and the 
having latest Nvidia drivers make a big diff. I was getting horrendous 
HD performance with 7167, and 7174 improved the situation quite a bit. 
Also, RenderAccel seems to cause problems in some situations, but that's 
hard to qualify. You can check some of this stuff by doing a 'cat 
/proc/drivers/nvidia/agp/status' to see what the system thinks of the 
agp status, and also 'glxinfo' which will detail dri and glx info. 
Sometimes you think one thing, but the system thinks another. I've got 
an amd64 3000 with 512 and a 5200 and I get passable (~85% cpu decoding 
1920x1080i without deint) performance. I'm watching for the fixes to 
XvMC with breathless anticipation.

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