What we need
For most audio post projects we need an OMF or AAF file with at least a 100 frame handles on all clips. The sample rate should be 48kHz with a bit rate of 16 or 24 bit.
If the project is to picture we also need a compressed Quicktime video file for reference. This should be SD, set to 640 x 360 dimensions with a 25fps burnt in timecode and encoded to MPEG-4.
For music mixing projects we can work from multitrack or stem files which can be delivered in either a project format(ie. Logic, Pro Tools etc) or in a folder(as long as all the files start at 00.00.00 on the timeline).