NextPVR Forums

Hi folks...my first post here after lurking for a few days.

My question is this: I've spent a week or two making a system based on MythTV under Linux. It is to be an inexpensive digital OTA box, using an Air2PC digital capture card (which is cheap and works great for my location, BTW), a P4 3.2 Ghz processor, and a Nvidia 6200-based GPU (128 MB), and 512 MB RAM. Myth software itself works great, and I'd be happy EXCEPT that I can't quite get the HD output to be what I want it to be. It's a little bit jittery, especially with onscreen movement. I've messed around with using just software decoding vs. using XvMC (http://en.wikipedia.org/wiki/XvMC) under Linux, trying different nVidia drivers, and a few other tweaks, but nothing can get me that last 10% of video performance that I need to make it good enough.

At first I figured that buying the cheap 6200 video card with only 128 MB was my undoing, but before buying a more expensive one, I've decided to try it under Windows, to see if the nVidia windows driver are better than the Linux ones, and I stumbled upon GBPVR, which seems pretty cool, and will be installing it in the next day or two.

Anyway, a question for anybody would be, is there any inherent difference that anyone knows about that would allow nVidia cards to perform better under Windows then under Linux, or will I just find the same limitations I had under Linux because the video card isn't good enough? Perhaps this Purevideo thing I've read about that nVidia has for Windows will be enough to get my system where I want it?

Anyone with any thoughts on this?

thank you

I tried to load MythTV

I liked the advertized features of MythTV and tried it.

I tried to load 3 different versions of it, on 3 different linux builds.
After a week of failure, I called my friends.
I spent 4 afternoons in a row with a Linux admin and a Linux programmer, and we still couldn't get it to work.

we then copied MythTV onto a CD just so we could have the satisfaction of smashing it then burning it.

I then browsed around for another PVR program, and ended up on GBPVR

the nvidia linux drivers are good, but will never be as good as on windows. mainly due to development. a 6200 would work great on either windows or linux. I've used a 5200 without a problem on both mythtv and gbpvr and it has handled everything i could throw at it (concerning tv things that is)


to me a jittery video might indicate a problem with codecs (either corrupted or not installed) what linux dist are you using?

to me a jittery video might indicate a problem with codecs (either corrupted or not installed) what linux dist are you using?

I installed using Fedora core 6. Install went very well. It loaded the driver for my Air2pc card, and everything else. Had to monkey around in xorg.conf a bit to get the nVidia card outputting to my HD set properly, but that was my only difficulty in setting up. Everything else went smoothly. Yes, I do agree, it's probably a codec problem. I wonder if the problem was because I installed from binary packages rather than compiling them myself. Oh well, trying GBPVR now.

Your 6800 card isn't optimized for HD content. You can see a comparison chart here, to see which features of HD replay your card supports. After that, you also need a codec that can take advantage of those features.

http://www.nvidia.com/page/purevideo_support.html

Your 6800 card isn't optimized for HD content.

I assume you meant my 6200 card?

By the way, my 6200 is an AGP, not a PCIe, so from that chart it does look like it has MPEG-2 decode acceleration. For some reason the 6200 in PCIe form doesn't support decode acceleration, but it does in AGP form.

I guess I'll know for certain soon....

True. I meant 6200, and I assumed PCEe

agidius Wrote:...
we then copied MythTV onto a CD just so we could have the satisfaction of smashing it then burning it.

ROFL!
It's been a while since I laughed so much from tech forums...

I actually wish I had done the same back when I tried the Linux based solutions... (and keep in mind I'm running my home brew Linux firewall/router/webserver/etc. so at least the basics Linux I know...)

compile you own drivers for sure. i have a mythtv box on ubuntu which makes you compile everything on your own (problem with some of the sql packages already installed).

biggest problem with linux and 2.6 kernel and HD is that timing hz have been compiled to 250 to be more laptop freindly. if you recompile your kenel to 1000 then HD works better. if you hack kernel a bit more to support much higher timing hz such as 2000 - 10000 depending on your machine you can get VERY stable picture..

if you need help with this I can point you in the right direction.. but vdr is a better choice HD under linux.. myth chew alot of cpu up

your easiest method of installing mythtv or VDR is to use mandriva 0ne 2007 and and the plf site to the software repositoiries. you will have mythtv or vdr up in running in 30 minutes..