I've got HD video that originated on a Panasonic HDC-TM700 camcorder. I copied it to my MBP, and converted the .MTS files to .m4v using ffmpeg. This file is playable in QT (7 pro or latest). Movie Inspector says it's H.264 video and AC3/5.1/48KHz audio. I can transcode this file to Apple ProRes with Compressor or QT 7 Pro, and read it into Final Cut no problem.
However, if I move the .m4v to my Mac Pro I hear no audio. QT still says there's audio there but when I play it it's silent. If I move the .MTS to that same Pro, and use ffmpeg to convert there I also get no audio. Compressor has the same problem on that mac.
I presume that means something is installed on my MBP that isn't on the Pro, but what is it? Any ideas? Is there a folder of codecs I should compare between the two Macs?