I recently got my system put together (specs below) and am having trouble playing HD video. I suspect that I'm not properly using XvMC, since turning it on in mythtv doesn't result in different playback success, nor does it result in lower CPU usage. I'm pegged out and dropping frames constantly. I changed the X86-Config4 file, or whatever it's called, to support 1280x720 resolution, if that's relevant to anyone. I am hooked up via VGA to my DLP television (incidentally the vga input on the television states that it can accept a 1080i/720p/480p inputs for display).

I'm a software developer, and learning quickly, but only started playing with Knoppmyth (and linux in general) for the first time this past week. As such, I'm pretty ignorant of most things that may be common knowledge to the people here that can help me.

Any advice you can offer would be greatly appreciated.

My specs are as follows:
R5A26
MSI K8V motherboard
AMD Sempron 3000+
ASUS V9400 (Geforce MX4000)
HD3000 tuner card
512MB RAM
200GB HD

well the quickest way to tell if xvmc is working is to just hit pause or anything else that brings up an osd if xvmc is working then the osd will be b/w instead of color. Since you are using R5A26 the nvidia drivers should have installed themselves, but it's worth double checking. you can see if you have a nvidia splash screen as X boots, and you can look in the /var/log/XFree86.0.log

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

Xsecrets

Actually, doing a fresh install seemed to fix me up. I don't think I have XvMC working, but playing back HD content with my Sempron 3000+ only sucks ~60-70% of the CPU currently...so I don't need XvMC.

However, I will try turning it on in mythtv and seeing if the menu during playback is in color or not.

For a little background, I had my HD3000 in the second PCI sloc (there was 1 free one between the HD3000 and the AGP slot), and I couldn't get any signal locks. In a bit of frustration, I did a major no no by playing around with apt-get and doing a little more than I should have. I later moved the HD3000 to the PCI slot next to the video card, and everything has been working perfectly since.

Hardware wise, I'm a tier 1 user, with no problems now.

My next step, tonight and tomorrow, is to try and figure out how to get the 3 audio jacks on my MB to output the 5.1 audio tracks for HD programs.

Hopefully it will go quickly and I'll be able to post my entire learning experience on this board for future new linux users like myself.

another thing to remember with xvmc is that it doesn't work with libmpeg2 for playback, so you have to make sure that checkbox is unchecked several screens prior to the xvmc checkbox.

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

Xsecrets

So riddle me this...without XvMC I have lower CPU usage than when i turn on XvMC...

I turn it on and the CPU usage goes to 100%. The video is mostly smooth, only slightly jittery, but when I bring up the menu it is b/w and the video gets very jittery.

Without XvMC, I bring up the menu and it's in color and the video remains perfect.

jkruppa

Sorry for deviating from the posted topic just a little, but jkruppa - if you get the 3 audio jack 5.1 channel sound working, please start a new thread on how you did it. I'd be very interested to hear about any new success stories (or failures, for that matter!) I've been playing with the alsa-mixer (amongst other things) for a while and still haven't gotten any but the L and R front to work.

jkruppa, how is your sempron 3000+ based system working out? I am getting ready to build out a new HD box and the Sempron's are quite cheap. Here are my questions:

1. What version of the nvidia drivers are you using?

2. What knoppmyth release are you using?

3a. Is XVMC still disabled?

3b. Are you using libmpeg2?

4. In your post you indicated CPU utilizaton of 60% - 70% during playback. What is the resolution of the recording you are playing back and what resolution are you driving the display at?

5. Is it stable. ie: Do the front-end or back-end ever die on you?

Thanks!

Marc

Marc, my playing with the box has been almost non-existant because I need to install an antenna in the attic to get reliable recordings. Unfortunately, I don't have a lot of new insight, but can elaborate on some of my previous information.

Q1/2. I was using the default installed ones from R5A26, which are 7xxx but I can't remember exactly.
Q3. I had mixed results and am not positive why, but some days it seemed I could watch without XVMC and without libmpeg2, and everything would be fine. Other days I'd have to watch with XvMC enabled. libmpeg2 did show a slight cpu savings over the default values, though.
Q4. All the broadcasters in my area are 1080i, and I was displaying at 720p. I've toyed with the idea of setting the resolution to 1080i and letting my television perform the deinterlacing to the 720p native resolution of the DLP chip.
Q5. The only stability issues I encountered are with forward skipping (30 second fast forward jump) too quickly, which is a known XvMC problem as I understand. And with the frontend/backend getting hosed periodically due to a poor signal strength. Once I get the antenna in the attic and am running MythTV 0.19 (which includes a signal strength monitor for the pcHDTV when watching live tv) I'll revisit any stability issues I have.

Now one of the things that may be important to you is to think about the difference between an Athlon 3k and a sempron 3k...the sempron has 128Kb (maybe 256Kb?) of cache, and the Athlon has significantly more. I'm not sure what the real world differences would be between the two, but you can bet it would be noticable and definatly in favor of the more expensive Athlon.

As a cursory followup to my indication about problems with 5.1 analog sound output, there is a ticket in the mythtv SVN repository for getting it working. I'm looking forward to that getting added, but it's not ready for prime time yet.

Good luck to you.

Even within the Althon 64s, the performance rating (+0000) at a given clock speed depends on cache size. 2.2Ghz 512kb == +3500, 2.2Ghz 1Mb == +3700