(I've just made the leap to Adobe Premiere from Final Cut, because I HATE the new FCPX and no, I'm NOT afraid of a new paradigm. Adobe's keyboard shortcuts alone are reason enough to be glad I switched. I mean - tilde (~) expands the panel you're hovering over to fill the whole screen?! And then tilde again puts everything right back! Sign me up.)
SO I had this problem which I solved in Premiere Pro CS 5.5 and i thought I'd mention it here.
I imported a few camera cards full of AVCAM / AVCHD footage from my HMC-150 and edited for a few days.
Then I clicked on one imported clip and found that the audio was wrong. Glitches, skips, out of sync, weird things happening - all nice sounding, but not in the right places.
I checked the original MTS files on my HD using VLC player. Sound was fine, everything was in sync.
I tried dragging the files into the Premiere project window, to see if it was a media import problem. Same thing happened when I did that - the identical glitches, which were the same every time I played the file.
So I started guessing that Premiere had imported it wrong, and had recorded some wrong metadata. That turned out to be the case.
I went to the "PRIVATE" folder where I'd copied my SD card to HDD. Premiere distressingly fills this folder up with metadata files associated with each clip, which violates the law of "DO NOT MESS WITH YOUR SD CARD DIRECTORIES." But it seems to cause no harm because it only ADDS files, it doesn't alter or delete any.
For each imported clip in .mts format, Premiere adds a file with the same name with .xmp as the extension in the same folder. Feeling bold, I quit Premiere then deleted all
these the .xmp files for that card - though i didn't empty my trash yet. I re-opened Premiere and double-clicked that file. It was dead silent, as clips often are when first imported to Premiere. It does some meta-data-ing... and then the sound was all back in proper order, problem solved.
The XMP files had been re-produced in that folder, although this time, apparently, without glitches.