Archiving Footage with de-bloated files

I have a Canon 60D, which I've started using to shoot video. However, the files it writes appear to be quite bloated because it doesn't use any motion analysis or advanced features — essentially it just compresses each frame, as they are all marked as “I-FRM” and the data rate is 44 to 48 Megabits/sec.

I posted a message on avidemux which includes details given by MediaInfo.

I'm thinking that it should be possible to re-save using other frame types and motion analysis, but tuning the quality settings so as not to make it any lossier than it was already, while reducing the file size substantially.

Does anybody know how to do this, or in general how to gleam the necessary information from an original file about what the quantization settings were?

Any advice on which tools I should be using (on Windows) is good too. My initial use has been using avidemux, which is easy enough to trim losslessly, and allows most everything to be specified for the underlying x264 library. My copy of Adobe Premere 1.5 is quite out of date and useless for modern files.

Thanks,
—John