[mythtv-users] HD playback using on-board nVidia

Peter Judge peter at judge.co.za
Thu Apr 14 20:32:02 UTC 2005


Has anyone succeeded in getting HD to work with an onboard MX440, using Myth?

I've got a Shuttle SN41G2V2B, which has the nVidia gForce MX440 on-board video card, and 512MB RAM. AMD 2500+ processor. I'm on 0.17 from ATRPMS, and using the 7174 drivers.

I've recently hooked my box up to my STB via firewire*. When I do the test capture using test-mpeg2, I can play back the HD content (PBSHD, which is 1080i) using mplayer. I get great picture and also get sound. CPU seems to be at about 60% for HD, and way down for SD. The only problem seems to be that there's blue-ish ghosting in some of the picture (noticable on ESPNHD, watching basketball).

When I try to watch HD using Myth, I get skippy picture (i.e. it seems to jump/skip over certain frames), although otherwise the picture seems good, and no sound. Well, every now and then I get sound, but it's basically just a crackle every couple of minutes. CPU is way up when I do this (can't remember exactly at what level now, but high, like 80 or 90 % CPU).

In both cases Mythbackend was running, although I will say that there wasn't a lot going on when I did my mplayer test, and when I tested through Myth there was a lot of activity (mythtranscode was running vigourously).

Reading this list, it seems the CPU is underpowered for a front/back machine; maybe it's worth getting a separate backend.

My original question was going to be: is it possible to play back HD with the hardware I have, but I guess I proved that already. So now I'd like to know, has anyone successfully managed to get HD working with a config  roughly like mine? And also, is it a good idea adding a new video card (which I can now do, because I can remove my PVR250 because of the firewire capture)? Is what I'm seeing expected, in line with others' experiences? 


* And many thanks to the devs for making it possible, and to Axel and Jarod's guide for making it so easy.

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