Greetings, all.

With a fair bit of Googling (and a large amount of luck?), I've managed to almost get my setup running ... including the Hauppage PVR-150 with remote and irblaster, and a PCI-based ATI Radeon 9250 with TV-Out.

However, now that I've got the TV-Out actually displaying on the TV, I find that Live TV is so choppy that I can't actually use it. I'm sure the PVR-150 is working fine, as Live TV was perfect on my Monitor before I changed the XF86Config-4 file to use the ATI card instead of my original video card (which is still in the machine). This leads me to speculate my video drivers (ATI Proprietary) or X configuraiton must be the culprit.

What are the most common causes of choppy video? Can someone point me in the right direction as to how to troubleshoot this? I've been a 'command line' Linux user just long enough to be able to get myself in and out of trouble ... but all this new video and X stuff is making my head spin.

Also, what are the implications of NOT using the TV option during the Knoppmyth install? What does this option add to the installation process (so that I can perform these steps manually, instead of going back and reinstalling from scratch?)

Thanks in advance,

- jert

1) DMA isn't enabled, check your hard drives and the PVR card for this.

2) Unaccelerated video drivers. (Make sure it's using the one you think it is, just because you installed it doesn't mean the XF86Config-4 isn't point to the vesa driver.)

3) Conflicting processes like mythcommflag.

Top shows my cpu running at about 85% ... There's probably a good chance that number 2 is the cause.

If the problem was DMA, I'd have choppy video using my first monitor, correct?

How does one verify that mythcommflag isn't running during LiveTV?

Okay ... I think I have the choppy video problem solved, by re-installing the ati proprietary drivers using the ATI Installer instead of going the RPM/Alien route.

I then used the aticonfig --initial --ovt=Xv options to configure the driver.

CPU utilization is down to 35%, and the video runs at full speed on the TV output.

However, I only see a portion of the video ... it's as if the video output is at a much larger resolution than the TV is actually outputting.

If you can ssh into the box and run top it should be pretty obvious. Unfortunately I don't think you've got an XvMC option with that video card to offload some of the MPEG-2 decoding. So you're kind of stuck with reducing CPU load by other means.

BTW - more hardware details might help...

P4 2Gig Compaq machine ... not sure of the motherboard chipset.
512 Meg memory

Hauppage WinPVR PVR-150
Generic AGP Video Card
PCI-based Radeon 9250 with Composite out to TV

As I mentioned, I've got the CPU utilization down to about 35% ... I can live with that for the moment - as long as I can get the video output to the TV working properly (ie. showing the whole picture instead of just a quarter of it).

The video being the wrong size for the tv seems to be coming from a line in my XF86Config-4 file:

Option "VideoOverlay" "on"

However, without this line, I go back to the choppy video I was originally seeing.

Guess I just need to do some research and figure out how to tweak the overlay ...

Ah. You didn't have Xv support enabled. That will do it. Look for your "overscan" settings (or something like that) to get the size fixed.

I'm not convinced it's an overscan issue ... my Mythtv menus, desktop, and games all appear with the proper resolution on the TV. It's only when I play video with Xv acceleration that things go wonky.

Is there a way to adjust the Xv resolution/overscan independently of the video/tv-out driver overscan?