Image quality issues when converting to psp




I tried one of the older versions in demo several months ago with no problems. However, with the lastest beta version release today and its predecessor I have problems with jerky video quality on many dvds following conversion to psp using the software defaults (1 and 2-pass endcoding). First noted the problem with Oceans Eleven and Raiders of the Lost Ark. Went back and reconverted some DVDs that had worked fine with older version and now they have the same problem. Has anyone encountered this before?