How can I record multi track audio with video

If you really need long runs (more than an hour) to stay locked in sync, you generate word clock from the video and sync your audio interface to that. Add time code to that for positional reference (on an unused track) if needed. Recording without sync lock for shorter runs is actually quite accurate in the current digital world. Just record a 'guide track' on the camera and it will sync up with the multitrack without the need for time expansion/compression work.

Thanks for the replies. I'd have to do some learning to begin using "word clock" or "alt sync". Those are new terms for me. What I would really prefer is just to be able to have a few more audio tracks that were already recording in sync with the video. If there is software like that out or if there's a way to run reaper in sync with the programs I already use for capturing the video I think that would be much easier for me.

The trick is having clear synch-points. It can be an obvious drum beat in the intro and one at the end, the singer shouting out "thank-you and goodnight", whatever, as long as you hear it when soloing the video and the separate audio and you can see that event in the peak waveforms. Record some test pieces and we can help you through the aligning process. It really is quite easy unless you've recorded 55 minutes of flies buzzing monotonously. I've done this dozens of times for live gig videos where there is a single camera. >