Video/audio 48 SYNC with released cd master 44.1 ?

lsstrat wrote on 9/23/2007, 1:53 PM
We shot a project with three sony pd-170 cameras recording room audio for sync.at the standard 48hz sample rate. The audio for the cd project was recorded separately in multi tracks, mixed, mastered and a cd master was made from the performance. Of course the mastered version from the cd will not sync with my video.

What's the best way to sync the mixed audio with my video?

1.) Resample from the extracted audio from the cd (will that sync everything up? AND keep the same pitch etc. (could it be that easy?)

2.) Get the audio in original 48 raw (mixed) and sync it?

3.) Any other suggestions?

(FYI - no copyright problems with using the cd master to video dvd- same project - releases signed)

Thanks much,
Jeff

Comments

Chienworks wrote on 9/23/2007, 2:21 PM
Normally the best thing to do is to put the tracks on the timeline and be done with it. Resampling isn't necessary as Vegas handles that for you automatically and invisibly. Now, when you say that they don't sync, do you mean that they don't start at the same time or that they run at different speeds? If they don't start at the same time then it's easy enough to slide one of the tracks left or right until they do line up. They should run at almost exactly the same speed.

If they run at different speeds you can line up the start, then Ctrl-drag the end of the CD track to the left to speed it up or to the right ot slow it down until the end of the performance matches. I wouldn't expect you'd be off by more than a couple of seconds. Vegas' default behavior will be to maintain the same pitch.
lsstrat wrote on 9/23/2007, 2:58 PM
Once I line up the start, let's say the opening vocals while seeing the lead singer, then the audio extracted from the cd will begin to drift. It definitely runs at a different speed. I'll try the CTRL-drag and see how close that puts me. I'll be switching views from three cameras and some b roll, so if something is slightly off, I can adjust. Just needed a simple way to get close.

Thanks

Jeff
Geoff_Wood wrote on 9/24/2007, 12:47 AM
The two versions should align hjust fine despite different samplke rates. Vegas doesn't care. If the tracks on the timelines can be manually aligned.

If somehow they have become different lengths, match up an audio peak on both tracks at the beginning. Then go to the end , and stretch the end of the event to visually align a recognisable peak there - everything in between should then line up too.

geoff

Do ensure that the setting to preserve pitch when stretching is enabled (Options | Preferences | Editing).
Geoff_Wood wrote on 9/24/2007, 12:48 AM
If that audio drifts, then surely something was set wrongly when sample-rate converted to 44K1 ? Or was it recorded on a separate and unsynched multi-track recording device ?

geoff
rraud wrote on 9/24/2007, 8:21 AM
It's not uncommon for digital sources to drift out of sync without gen-lock or TC. However this is normally no more more than a frame or so in an hour depending on the video and audio recorders.
Calculate the sync error (in frames) at 10 minutes and 20 minutes, this may give us a clue. It you state what camera/ VTR and audio recorder were used, this may be a clue as well.
Was the video shot in 24p or other than standard NTSC?