I was pocking around the UK Hauppauge site and noticed that all recent versions of the PVR 150 driver have turned off the "comb filter". Some suggested this could cause a "softer" picture. Which is what I am seeing (almost blurry).
Has anyone been able to turn back-on the "comb filters", there appears to be a registry hack for this, haven't tried it yet.
It's a PAL thing. If you're not US, I'd say look into it.
The default comb filter was "2 line chroma comb, threshold at 0x50(ish)". Since 23172 (or thereabouts) the comb filter has been turned off for PAL, but can be overridden.
Comparison
No Comb Filter (default)
![[Image: 23297NoCComb-Defaults.jpg]](http://i6.photobucket.com/albums/y207/CX23882-19/23297NoCComb-Defaults.jpg)
Comb Filter at old defaults (2-line chroma comb, default threshold)
![[Image: 232972LNCComb-ThresholdDefault.jpg]](http://i6.photobucket.com/albums/y207/CX23882-19/232972LNCComb-ThresholdDefault.jpg)
Notice how much better defined the vertical lines are with the comb filter on. But there is a small amount of dot crawl artifacts in areas of really bright colours (but it's hardly noticeable in "real life" images - not as much as some people make a fuss about).
However, if the dot crawl artifacts are too much, you can play with the thresholds (values between 0x0f and 0x1f are a nice compromise):
![[Image: 232972LNCComb-Threshold0x1f.jpg]](http://i6.photobucket.com/albums/y207/CX23882-19/232972LNCComb-Threshold0x1f.jpg)
Personally I'd just give the default settings a shot. The dot crawl isn't that bad, and no worse than most other devices. Some people claim that their older BT878 cards don't show dot crawl with the same source - true, they don't, but the only reason for that is because the horizontal resolution is extremely poor by todays standards. I did have the same test image on my BT878 card and ALL of the vertical lines were just blurred - i.e. if there is dot crawl you're not going to see it because the chipset is just not capable of that level of detail.
Finally had time to download the registry change turning the comb filters back -on. Yes there was quit a bit of improvement in the picture!! In particular the blurriness/fuzziness has been replaced with a sharper picture.
Dot crawl has increased somewhat but not enough to turn the comb filters back-off. According to the original UK thread the change was made to improve the picture in PAL land, well it worked in NTSC land as well.
I am using a SDTV "Comcast Cable" (non-digital") composite signal from PVR150 to 27" JVC 4/5 yr old TV.
There is a link posted by "erik" in this thread if you want to give it a try.