I used I-ShowU to create screen caps, and the resulting QuickTime movie has great image quality. For some reason, I can't get a consistent output from Premiere Pro, though. I can create a test that works, but when I render the entire movie using the same specs, I get pixilation.
The compiled movie consists of a title sequence created in After Effects, followed by about six minutes of edited QuickTime movie.
I've been switching the Clip>Video Options>Frame Blend and/or Scale to Frame Size to get the inconsistent results. I used H.264; 30fps, 1024x768 frame size on a Mac (10.5.6) with 6Gb of RAM and acres of disk space. Those settings were used for capture with I-ShowU, and export from PE.
Here's a screenshot of my results - from left to right, original QT movie, Acceptable output from PE (that I can't get for the whole movie), and the usual pixilated garbage I'm stuck with. http://www.nidus-corp.com/ImageQualityProblem.jpg.
Is there some sort of formula method that I can follow? A button I'm not clicking? A dialog box I've missed? I've searched the forum and the tutorials, but the answer hasn't been obvious to me.