[mythtv-users] HDTV playback specs?

Matt Goebel matt at goebelnet.com
Sat Sep 2 20:08:19 UTC 2006

I've just upgraded to an HDTV DCT6200 cable box from my cable company.  
Using firewire and MythTV's built in DCT6200 support I'm able to 
watch/record all my HDTV channels, premium (HBO/Showtime/Etc) and 
otherwise, as well as all the regular SD and digital channels.  The 
problem.. while HDTV playback is *almost* smooth it still shudders, gets 
out of sync with audio, and sometimes there is that "snowy" pixel 
effect.  It not that bag, but even a little makes things annoying.  Here 
are my system specs:

AMD 64 2000+
1GB PC2100
DFI nForce 2 based motherboard
NVidia FX5200 /w 128MB (AGP)
Generic firewire card (NEC chipset)
Onboard gigabit NIC - (100Mb connected but could be 1Gb, don't see a 
point since SD recording only used 5Mb/s per tuner, even if HDTV is 10x 
that... ???)
80GB ATA/133 drive (all recording on a NFS 4 network share.)

All this system does is MythTV.

Watching HDTV my CPU usage runs anywhere from 35% to 85%.  The norm is 
~75%.  Memory and disk i/o is almost nill.  This is with XvMC enabled, 
Bob2x deinterlacing, frontend running with root privileges.   I've also 
set the nvidia options in xorg.conf :

Option "RenderAccel" "1"
Option "NVAGP" "1"
Option "XvmcUsesTextures" "false"

Recording HDTV /w out playback I see 3% CPU usage.  Watching HDTV from 
my much faster master backend is flawless. 

So given all this what has been people's experience?  Can I get 
completely smooth playback with these specs somehow?  An option I am 
missing etc?   If not what's the most worthwhile  part to upgrade?

I have a couple ideas:
1. Replace my FX5200 /w a fanless 6200 with 256MB ~$50 (enough of an 
2. Replace with a fast Socket A CPU ~$100 (enough?)
3. Both 1 and 2
4. Use a first gen Nforce 4 board I have laying around (Socket 939)  and 
buy an ~ AMD 64 3200+, 1-2GB PC3200 DDR.. all new PCIe 6200 - ~$$$

I'd prefer not spend all that much since all I want is a MythTV frontend.


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