I’m assuming you mean Quicktime with the source Avid Codec – a large Quicktime file, rather than a Quicktime reference which is usually under 100k. Do you have to a Mac with the older OS? Unfortunately, I don’t believe Avid supported the old resolutions when they went to OSX with the Avid Codecs. I’ve had to go back to an older system (with the correct Codec) and use After Effects to convert to a file that the OSX-based system can read.