[mythtv-users] Optimizing HD playback with VDPAU?

[Matt Goebel]

I have a couple shiney new mythfrontends that I'm doing almost all HD 
with (HDPVR and HDHomerun).  One system is a backend/frontend the other 
is just a frontend.  For the most part they both work flawlessly.  
However, on the frontend only system I've noticed every once and in a 
while I see a very mild video stutter when there is a lot of motion 
going on, audio is fine though.  Most people probably wouldn't notice it 
but I do.  Same system every once in awhile while I'm watching live TV 
I'll get a couple second freeze then resume as normal as well.  Even 
when both issues aren't happening I don't seem to be getting the same 
lifelike motion that my 120Hz Samsung LCD gives me with when it's 
directly attached cable box.  The other frontend/backend I don't have 
any of these issues that I can tell.  It's attached to an older Samsung 
DLP though, so I may just not notice it.  I've played with just about 
every setting I can think of but nothing seems to make a difference one 
way or another.  A little more info on my setup:

   1. Both systems have MSI N210-md512h (VDPAU C) cards, using VDPAU
      normal with both, vdpaubuffer=50.  Both have 5.1 HDMI audio
      working.  The frontend only system is in a hotter environment
      though, so that card runs hotter at ~65-70c during HD playback.
      (after adding a slot fan)
   2. I'm using all intel 1Gbit NIC's with Jumbo frames (MTU=9000)
      enabled on both systems (and the switch of course as well too).
   3. The frontend/backed is i7 based with more memory (does a bunch of
      other things), the frontend only is a lower power Athlon II X2
      250..  I've bumped the minimum CPU stepping on the Athlon to 1800Mhz.
   4. Fedora 12 x86_64 /w myth 0.23 on both (using all storage groups)
   5. I'm not getting any errors anywhere that would indicate a problem


Based on all this:

   1. What would you guys suggest I have in my xorg.conf and Nvidia
      settings?
   2. Has anyone tested MTU's at 1500 vs 9000 with MythTV?  Latency vs
      throughput, not sure what's best in this case.
   3. Do you think heat could be an issue?
   4. Do you think the lower powered processor could be at fault?  (only
      at ~ 4% during playback)
   5. With a 120Hz LCD would it be worthwhile to buy a different (better
      220+ Nvidia based card) so I can do VDPU high quality?
   6. Any other suggestions/settings I should try?

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