A long while back I made a project on Premiere and exported it using IV50. These days, I use a Mac G5, Final Cut, and Compressor. I have a high res copy of a movie file exported with IV50, which I need to compress to something web hostable. But in my internet searching, it seems that they never made IV50 support for Macs, but surely SOMEBODY out there SOMEWHERE has devised a way...right?
I'm assuming the IV50 you speak of is the same as Indeo Video 5, and no, it wasn't ever ported to Mac OS X. But, some slightly good news, it was ported to OS 9, and if you use Classic and QT 6.0.3, you should be able to parse it (after finding it for download) and convert it with QT Pro. Probably, the best thing to do would be to export it from QT Pro 6.0.3 to Photo-JPEG 100%, and then use the new P-JPEG source to export with Compressor or such in OS X.