How to convert HD (.mts) to DV-AVI for use in Premiere 6.5?

Hello everyone,

I need to convert HD (1920x1080 .mts) footage to standard definition DV-AVI for use in Premiere 6.5, which doesn't support HD. What software can I use to do this?

I've experimented with a number of trial versions of conversion software, like Aimersoft, Aiseesoft, Wondershare, etc. Unfortunately, as far as I can tell, none do what I need them to. There are some options for AVI, but none that seem to be exactly the same as what I get when I encode with Premiere 6.5. I see options like DivX, a few formats for gaming consoles, and a few others. But the option that has a description that's closest to what I need actually corresponds to a .dv format, not .avi, and I can't use that.

Also, since HD has proportions that are very different from the 720x480 screen size I get with Premiere 6.5, I need the resulting videos to be letterboxed. Again, I don't see any options that do this. But even if I did find such an option, there would still be a problem. See, I eventually convert the 720x480 DV-AVI clips to 640x480 WMV clips, as well as DVD (MPEG2). If the software doesn't take the horizontal picture stretch of the standard DV-AVI 720x480 footage into account, I'll end up with squished videos. How can this be avoided?

Any advice would be highly appreciated. Thank you for your help!

Francois