[mythtv-users] AppleTV with Linux

Scott D. Davilla davilla at 4pi.com
Wed Feb 20 02:19:58 UTC 2008

>Figuring out the hang and video corruption issue during xvmc decode
>are the biggest issues right now. Once I solve those, all the other
>issues are trivial. Testing the various changes takes a lot of time
>as the two issues are random and might take several hours to occur.
>For example, I made a change last night and run 4 hours straight
>before I got a hang. Before going to bed, I made another change (send
>audio to /dev/null) and it was hung again in the morning but a
>difference type of hang, I could escape back to the main menu. There
>are many variables in play.

Just a quick report, I switched to mplayer to simplify debugging the 
xvmc hang/video corruption and I'm happy to say that after much 
investigation, I think I might have it solved.

So far, mplayer has been running continuously for over 12 hours doing 
xvmc 1080i mpeg2 decode from a HDHomeRun. Not a sign of any glitches.

The trick seems to be underclocking the nvidia gpu. The "standard" 
clocks reported by nvidia-settings is gpu = 360Mhz and vram = 720MHz. 
I'm running at gpu at 200MHz and vram at 800MHz. Interestingly, the 
vram speed effects xvmc decode performance more than gpu speed.

I have to backout of some kernel config changes and patches and 
retest under myth to be sure but I've never seen 1080i xvmc run this 
long without glitching.

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