If the mix is final have them export a 48K stereo AIFF. Import the file and lock it up to your original seq - matching the final mixed tracks against the audio tracks that are still in the timeline. Dupe the seq and blow away the old audio tracks. Lay it to tape and go home.
Note - the sample rate of the Protools export should match the sample rate of your project - hopefully 48K. Also, I believe Avid works at 16bit instead of 24 bit (If the sound designer asks).
So don't worry about the timecode? Just line up the waveform of the stereo mix of the multitrack recording to the tracks (house mix) that I digitized from the videotape? Sorry for the clarification, I'm a little hazy myself. Allergies got me down.
Thanks for your help!
Sure, lining up the waveforms is one way to skin the cat. Personally I don't like using waveforms because I don't like waiting for the waveform to redraw. I'll mark a rough in point on the source that matches the start of the music or a big hit in the music. Lay it down on the timeline in the appropriate place on trks 3&4 (assuming that that existing audio is on 1&2. Playback listening to all 4 channels. Chances are I'm a few frames off so I'll hear an echo in the music. Go into segment mode or trim mode and bump the new audio 1 or 2 frames at a time until the audio is in sync. It's very easy to tell when the audio is in sync - instead of hearing an echo it should sound like phase errors, a hollow sound. Yeah the audio now sounds bad but this is good, the audio is in sync. Dupe the SEQ and delete the original audio on trks 1&2. Your good to go.
Pro Tools works at sample rate rather than frame rate. What does this mean? Depending on the number of effects the Sound Designer used in the final mix there may be a delay in the audio that's doesn't exactly equal 1 frame, maybe it's a half frame or quarter frame. For 95% of the work out there - give or take half a frame is close enough. For critical work there are workarounds to this, but that's an entirely new thread.