Advice/Approach to sync 6 floating heads singing

I'm hoping for some advice/basic approach for a project I'm working on.

The basic concept is to project six heads onto large masks (24" tall) all lip syncing a song.

I'm filming separately several peoples heads singing along to the song on green screen. I filmed them 1080p (I probably didn't that high res given my project is not great) I've keyed them and cropped them in separate projects. I'm then looking to combine these 6 heads into one project with the song and attempt to sync up each of the tracks or at least visually to the song.

This is what I'm thinking. Key and crop each head in separate projects. Should I export to master, import back into events and drop the new events into a new project with the song? Or just copy from each project into my main project?

Then, what's the best approach to sync up the lip syncing with the song? Besides having a hard to syncing up, I also hit lag once I add multiple heads. Media is on latest MBP Retina's internal SSD with plenty space and 16GB ram.

Thanks in advance for the help.

I would assume when you had each of these 6 people sing, they were singing to a scratch track. You should be able to just put that track in FCP and then sync the song audio to your cameras audio from their vocals.

After syncing, possibly using multicam or just manually, I would then just key and crop in the same project. If its having a hard time playing, maybe create proxies for the video files and do it that way.

Thanks Muddygun

I filmed three so far. Each one separate. Each one lip syncing to the track we played in the background on the stereo (scratch track?) So 6 separate events imported. I then keyed and then cropped their heads tight all in separate projects. I wasn't sure if you thought I filmed them all at once. I'll end up needing to scale and position each head exactly where the masks will be to then project onto.

So you would drop in the 6 events into a single project, key, crop, scale while in the one project and then sync to audio?

Thanks again for your help.

well, since your computer is having trouble with the videos all at once. I would say do what requires fast playback first. Which would be the audio syncing. Leave them with the greenscreen and no cropping. your MBP should be able to handle 6 1080p streams...if not, better than keyed out footage.

I know you filmed separately, but usually what i do when filming is make sure i have a beat to start on with each record. that way i can match the beat of the original song, to the beat that is recorded on camera. If you have just clean vocal audio (and no beat to match too), then i would just have both the original song and one vocal playing at a time and match it that way. It should only take about 30 seconds to match each voice to the song. If its taking longer, than something might be up.

I'm a tad slow here, so help me out. Do you want to show them all at one time on the screen, or cut between them Multicam style?

Thanks Muddygun. Good advice.

Hey Ben

They'll all be up at the same time. Each one scaled and positioned for a given mask. So six heads projected on 6 masks at the same time. I may also swap in additional people singing and not stick to just one person per mask.