When ever I need to composite files from editors they typically try to give me Quicktime Reference from Avid, but has been a hassle due to different network mounted drives which make all the references break. If you get a QT Reference then make sure you get all the source files and that they are where you can easily access them. Personally I started having them render to Quicktime with the PNG Codec. It is a lossless codec that has made files 1/6th-1/10th the size of an Animation encoded file.
Hope this helps,
-Eric