Selecting unique frames in tmpgenc

Hello, I've got an AVI of a music video. It's rare and I'd like
to clean it up. Problem is, the frame rate is 29.9, but if you step
thru the video frame by frame, only about 15 fps are unique.
The avi is progressive, but I'm attempting to use Tmpg
"inverse telecine tool" to select the non-interlaced frames.

Main problem is that there is not a clear pattern of the way
the unique frames are placed. So very difficult to use the inverse
telecine function in Tmpg to set a pattern and select the unique frames
automatically. Looks like I'll have to do the whole thing manually.

Any other tool that may help?
Thanks, Dave