Audio Sync: 5dMK2 / Zoom H4 / NeoScene / Sony Vegas at DVinfo.net

Rich Castro · September 10th, 2009, 03:08 PM

I posted the following on the 5d message board but thought I'd give a try here as well as someone mentioned they would love to hear from David on this one.

http://www.dvinfo.net/forum/canon-eo...ony-vegas.html

Can someone offer a suggestion?

Quote:

Originally Posted by Rich Castro

So I while back I purchased a Zoom H4 for use with my 5D. I process my clips using NeoScene and it is my understanding that NeoScene converts the 30fps footage into a more standard 29.97. I’ve made a few test recording trying to sync up audio using the H4 and the 5D (and a pocket AVCHD Panasonic TS1) but have had no luck. In a very short amount of time, the audio would drift badly. I did some searching on the forums and found this post and thought it would be a great solution:

http://www.dvinfo.net/conf/canon-eos...ml#post1095886

I tried as Jon said, sync’d a clap in the beginning and end , but the audio is still drifting somehow in the middle. I’m guessing it’s user error on my part, but can anyone point me in the right direction? This same solution seems to work just fine on my Panasonic TS1, so I’m going to have to guess it has to do with the 30 > 29.97 conversion?

Unfortunately, due to a work travel, I had to return the H4 since I wouldn’t have enough time to properly troubleshoot and test. But now I have some time and want to try and get this figured out if someone can point me in the right direction.

Does anyone have a good workflow with the same setup? (5dMK2 / Zoom H4 / NeoScene / Sony Vegas)

Thanks in advance,

Eugenia Loli-Queru · September 10th, 2009, 03:42 PM

You need to change the KHz rate on the audio file in an audio editor to match the change from 30 -> 29.97. A bit of algebra is involved (don't ask me, I am bad at it).

Graham Hickling · September 10th, 2009, 08:16 PM

Or.... just timestretch in your audio app, specifying that the overall duration of the audio becomes identical to the video. No math required!

Bill Binder · September 11th, 2009, 02:51 PM

So wait, you're synced at the head AND tail, but it's still not synced in the middle. Something is VERY wrong. Are you sure you're still synced at the head after syncing the tail? Remember, you should be slipping the event to sync the head, then STRETCHING/SHRINKING the event to sync the tail. If both are synced, then the whole thing will be synced.

BTW, for those going down the 29.97 vs. 30.00 route, this problem is more about two different word clocks in two different devices than it is about frame rates.

September 10th, 2009, 03:42 PM	#2
Eugenia Loli-Queru Major Player Join Date: Jun 2007 Location: Bay Area, CA, USA Posts: 348	You need to change the KHz rate on the audio file in an audio editor to match the change from 30 -> 29.97. A bit of algebra is involved (don't ask me, I am bad at it).

September 10th, 2009, 08:16 PM	#3
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	Or.... just timestretch in your audio app, specifying that the overall duration of the audio becomes identical to the video. No math required!

September 11th, 2009, 02:51 PM	#4
Bill Binder Major Player Join Date: Jun 2005 Location: San Francisco Posts: 542	So wait, you're synced at the head AND tail, but it's still not synced in the middle. Something is VERY wrong. Are you sure you're still synced at the head after syncing the tail? Remember, you should be slipping the event to sync the head, then STRETCHING/SHRINKING the event to sync the tail. If both are synced, then the whole thing will be synced. BTW, for those going down the 29.97 vs. 30.00 route, this problem is more about two different word clocks in two different devices than it is about frame rates.