If you're receiving H.264 camera masters, I assume your client is shooting on DSLRs.
I don't recommend MPEG Streamclip for this operation. Make sure your client retains the complete, untampered file structure on each memory card he shoots and backs up.
First choice is Final Cut Pro's Log and Transfer, which can retain time-of-day timecode, and will also automatically retain the original frame size, frame rate, etc. Second choice is Compressor, but make sure the client is very meticulous about what settings he used (especially if, for example, he uses mixed frame rates and sizes). Compressor and MPEG Streamclip can both alter the spec of the media in undesireable ways.
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