R5A30.2
Intel D845WNL
Intel P4 @ 1.8 Ghz
1 Gig RAM
Hauppauge PVR-150 (Non-MCE)
Motorola DCT-2000

This one has been very tricky for me to figure out. I am hoping someone can point me in the right direction.

While watching live TV or while recording, after "X" channel changes (exact number varies) the picture on the screen seems to pulsate between clear and pixelated. If I am recording a program, I can see the pixelation happening. If I happen to be watching Live TV, sometimes the front-end will crash.

At first, I thought this might be related to using an external channel changing program. However, today I experimented by watching "Live TV" and accidently noticed that if I manually change the channel using the set-top box very rapidly, I get the pulsating pixelation problem to appear.

It almost seems that Myth can't handle the video signal changes caused when the set top box changes channels.

I have no idea where to start troubleshooting something like this. Has anyone heard of a problem like this before? I have already tried moving to a new cable outlet, swapping set top boxes, etc. but nothing seems to resolve it. Any help is appreciated.

Next time you see the pulsating, don't change anything but plug the output from the cable box directly into the TV. See if the TV shows the same problem.

What input on the pvr-150 are you using? S-video I assume. I have no idea why the pvr-150 would have trouble after channel changes. Once you get the pulsating effect does it ever go away? How about if you wait a minuet and then change the channel agian, does the pulsating follow to the next channel?

How large is you ringbuffer partition? Maybe it is having trouble once it gets full and must write/deleate/read all at the same time. If this is the case it should be mostly taken care of with the ringbuffer removal in mythtv .19 Also make sure you have DMA turned on for your harddrive.

Update your IVTV drivers,

Follow the instruction on the knoppmythwiki.

I have seen it resolve issues like this before.

Thanks very much for the replies. I am going to try out these solutions this weekend. I'll start with the basic troubleshooting and then also give it a whirl with upgrading the IVTV drivers.

Thanks again!