[mythtv-users] Xbox frontend really slow, video only updates every few seconds

George Nassas gnassas at mac.com
Mon Feb 13 04:37:10 UTC 2006


On 12-Feb-06, at 3:34 PM, Daniel A. Segel wrote:

>> The top several processes are all mythfrontend. It's using ~60-80% of
>> the cpu, followed by XFree86. Everything else is using 1% or less.Only
>> 100MB of my 256MB swap is in use. It actually plays a second or two of
>> video, then freezes for a few seconds, then plays again for a few
>> seconds. This repeats as long as I let it. I'll try setting things to
>> 480x480 and see if that helps.
>
> OK, 480x480 seems to work well, but I don't like the "soft" image. I
> guess I'm just spoiled by the PVR-350's nice picture.

I made a 720x480 recording at a bitrate of 6000 avg / 9000 max and my 
xbox plays it back ok so that doesn't appear to be an issue. It didn't 
occur to me to do a top while playing back that recording but watching 
a 480x480 one uses a steady 30% of the cpu.

I guess I'd wonder about how myth is interacting with XFree but there 
doesn't appear to be too many options there. On my playback setup 
screen I have deinterlacing off, no filters, standard mpeg2 decoder, 
open gl sync on (although I'm not sure it's relevant on the xbox), 
realtime threads on, video timebase off and extra audio buffering on. I 
keep forgetting to chmod +s when I update the executables so the 
realtime setting isn't doing anything at the moment. My frontend log 
says it's using USleep with busy wait for video timing.

The only other possible difference is I build my own debs from svn. My 
script tweaks the rules file to pass --arch=pentium3 to configure. The 
default is --cpu=i486 --tune=pentium4 --enable-mmx.

That's all I've got. Probably it's not helpful but at least you know 
you aren't hitting a hard limit of the xbox.

Oh, I wouldn't worry about the multiple frontend processes - they're 
actually multiple threads within the one process but top & ps don't 
know how to deal with them.

- George



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