I guess 'native' isn't the specific terminology I was going for, just that my projector will accept 1024 x768 and scale it to 848x480. It works (and looks) much better when I set an xorg.conf modeline to 848x480.

Right now it sounds like we have identical problems. After some further experimentation, I found that after the box has been running for a while (24 hours), software playback of an HD stream no longer works well. After a reboot, it works OK (but not great) again. The prebuffer pause messages occur about every .04 seconds in either case with XvMC enabled.

So you're running a 3GHz P4, and an FX5200. What motherboard? I wonder if a bios update would make a difference.

It's a Shuttle ST62K "Zen" SFF box. The FX5200 is in a 66MHz
PCI slot, which is probably part of the problem -- that's way
slower than an 8X AGP slot.

_________________
Grant

You've got an integrated Radeon 9100 on there, right? I'd be willing to bet that software HD decoding would work on that, but I think XvMC should work on the 5200 pci (you don't have to move as much data across the bus with XvMC).

Your best hope may be the open source ati drivers trickling out, now that AMD has released the register specs.

I have a similar setup (P4, 3GHz, HT, nVidia 5200) and XvMC works for me, but only at HD resolutions, i.e. 1080i or 720p. When I watch a 480p signal (like Fox NFL) the playback goes into a slow "crawling" mode like it is running at 1/4 speed. It's not CPU bound, but something else going on.

Otherwise, XvMC is working pretty well on this system. I just updated it to R5F27 and it works with software decoding, but I notice some glitches during playback at 1080i. The only thing that keeps me from using XvMC is this slow-mo mode on 480p signals.

My system:
Abit AS8 m/b
1G RAM
Pentium 4 3.0 GHz HT
400+750+750 Seagate disks
HD-3000 (2) and HD-2000 (1) capture cards
nVidia 5200 based video card, AGP 8x (I think)
Pioneer RPTV set (1080i only)

_________________
Do you code to live, or live to code?
Search LinHES forum through Google

Liv2Cod-

There's a way to use XvMC only with the HD, but its not intuitive, and I think its detailed somewhere on this forum. I've seen it recently, but couldn't find it on a search.

Right.

Nope. I tried it with both the fglrx driver and with the xorg
"ati" driver. 720P stutters badly, and 1080i will hardly play
at all.

That's certainly what I thought, but it looks like I was wrong.

The press release that I read listed the chipsets for which
specs were released. The 9100 wasn't one of them. It looked
like they only released specs for newer chips.

_________________
Grant

From the mythtv.org wiki;

Thanks Kirk- that's the one. That should fix Liv2Cod's issue anyway. Grante and I are still outta luck.

I did find something interesting tonight. Remember how I mentioned that software playback could pretty much keep up watching live HDTV? Well, it was stuttering like crazy when I was doing some testing tonight (the wife is out bowling so I've got a few hours). Turns out I finished recording something at 9, and mythcommflag is eating up ALL KINDS of processor time, but is not when HDTV is playing smoothly under software. Looks like my solution is to get a slightly faster processor, use software playback, and turn off commflagging. Anybody know how to effectively turn off, or better yet throttle or schedule commflagging?

edit- never mind I found the solution right here on the forums:
http://mysettopbox.tv/phpBB2/viewtopic.php?t=13614

Check if your recordings at 720X480, 640X480 or 480X480.

It could be that when you force it to display at 640X480 it causes your 100% CPU?

For what it is worth, I run 1080i on my Athlon 3000 (single core - 32 bit) with a Nvidia 5500 card in an AGP slot. It is right on the borderline of what works. To make it work.
1)I have to keep XvMC turned OFF. I'm not sure why but it drives the frontend usage up from 65% to 85%. It used to be the other way around.
2) I also turn off deinterlacing since the TV handles that.
3) I also have to disable mythcommflag. Anytime that runs I get a mess with hesitations, jerks and pops.
4) Just to be safe when I set up I also refuse things like rrd, fold@home, and anything else that would need any power.

These latest few editions have made it run much sweeter and I have only one channel that gives me trouble, but I think that has to do more with the reception.

There was one person (I don't remember who) who was making HD work with an Athlon 2400. So you aren't far off the mark