I was running an underpowered P3-733 with an old nvidia card in it and my cpu was pegged. After some research I decided on buying a cheap nvidia fx 5200 based card ($32 after rebates) to try to make use of some hardware decoding and free up some cpu.

I decided to reinstall completely when the new card came (mostly because I messed it up trying to install kde to compile mythbrowser).

When I start viewing livetv and check the processor idle I am very happy with the 50-60% idle. It is displaying the channel nicely and the audio is keeping up (I had some breaks in the action before).

However, when I change channel the video & audio freezes (along with the mini channel change, time etc on the screen). The harddrive continues to go as it appears that my hauppauge 250 is continuing to encode and the software seems to be still running (I can CTRL+ALT+F1 to the console).

If I turn the XvMC hardware decoding off then it works fine without any freezing (granted my cpu is pegged and I lose some frames/audio because it can't keep up).

Any ideas?

this is one of the problems with xvmc right now. you can try to remove the fade for the osd, but it still has problems sometimes, and there is no known solution at this time.

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Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

just so i am clear -- xvmc basically tells myth to let the graphics card handle the mpeg-2 decoding? is that true. i guess i am wondering if i will get any benefit from having hardware decoding on this graphics card if i am using myth.

also, is this a knoppix myth distribution problem or is it a myth problem?

i will doublecheck the fade for osd, but i am pretty sure i removed that right off as it was one of my "cruddy cpu" optmizations i was making.

thx

this is an xvmc problem. not specific to knoppmyth or myth necessarily. from my understanding, and I am not a coder or video genius, but people on the dev list say the way it's implemented isn't that great. if you want more detail search here and on the mythtv mailing list. It's been discussed in depth. It's being worked on, but I don't think there is an expected resolution in the near future.

_________________
Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

Just a little information on this one ... it appears the problem is actually with XvMC and the OSD. When the OSD does the fade back (defaulted to 3 secs but configurable) it eats more resources and if you have a slow machine it causes the hardware encoding to die.

You will notice that when you select XvMC that your OSD is actually in black and white -- this is try to reduce some of the cpu stress (atleast that is how I see it). You can change your OSD so it does the lowest CPU fade which helps some people (not me) and and you can remove the deinterlacer or change it to use BOB 2-frame which apparently works for some people.

My best result has been with deinterlacing turned off and changing my OSD to say for 30 seconds (as odd as that sounds). What happened was I could move around as long as the OSD didn't fade away, and actually when I did watch something for 30secs it did fade away without killing my hardware decoding.

Anyway, I located a hack someone put together that is supposed to help solve the problem. Once I apply that patch I will post more (if I have any good results).

- chow

Ok I came up with a solution that has XvMC working on my underpowered P3-733 box using an FX5200 card. Basically what I did was modify /usr/share/mythtv/themes/osd/osd.xml (I think that is the right path). There is a line that indicates the number of steps for the fadeaway (it is about the fourth line) ... I changed it from 30 steps to 0 steps.

The impact is when the OSD goes away it doesn't fade (which is causing the problem). It isn't great (cuz I like the fade) but now it doesn't freeze-up my replay. Whenever my OSD is on the screen it gets a little choppy so I try to avoid things that keep the OSD up. This includes my fullscreen guide which is a touch choppy for me while I am looking through it - but still very functionable.

Woohoo!

stewy26 I am definetly going to give this a try when I get home from work tonight! I'll report as to whether or not this helps me as well!

Thanks for all the effort and posts thus far everyone!