I reported the following problem to Cyberlink:
"if I enable both clearvideo acceleration and de-interlacing in PowerDVD 9 Ultra I experience extremely jerky DVD playback. Playback is smoother with de-interlacing disabled, but with severe combing instead. The problem only appears to be evident when watching video full-screen (at 1920x1200), and only affects (or more severely affects) film footage (as opposed to animated). The effect is most obvious on pans and zooms, where the video seems to alternately speed up and slow down or skip. It affects both PAL and NTSC discs. I don't have the same problem with Blu-ray discs."
Before reporting the problem I uninstalled and reinstalled the latest version of the intel drivers and PowerDVD. Their eventual response:
"that this is due to VGA hardware deinterlacing and it can not work fine. I suggest you to contact your VGA card manufacturer to provide you the updated drivers."
Now since both their site and intel's specifically state that PowerDVD is optimised for Clearvideo this seems like a cop out.
Operating System: Windows 7 Home Premium (64-bit)
VGA: intel GMA 4500MHD
VGA driver version: 18.104.22.1686
Audio device: Realtek HD audio
Audio device driver version: R2.44 (22.214.171.12466)
display connection: HMDI out, DVI in
dual monitors, extended mode
Antivirus SW: Microsoft Security Essentials.