Syncing Zoom H4N/H1/etc. Audio to 24p at DVinfo.net

Zhong Cheung · April 18th, 2011, 05:45 PM

So many of us are using DSLRs/EVIL cameras to film weddings at 24p. However, many are also using external recorders such as the Zoom H4N or H1 to capture better audio than the onboard audio the camera can obtain.

How do you sync this external audio with your 24p footage? For example, I'm hearing the Panasonic GH2 does not even shoot 1080p at 30fps, basically forcing you to choose 24p if you want to stick with 1080p. So, what is your process of syncing without causing audio drift?

Chris Hurd · April 18th, 2011, 06:02 PM

What editing program are you using, so I know which NLE forum to move this to?

Pete Cofrancesco · April 18th, 2011, 09:13 PM

Audio drift isn't caused by the frame rate or resolution you film at, it only happens when the internal clock of the two devices is significantly different. Do a test by recording 10 minutes continuously with both devices starting and ending with a noise to measure the drift. If you are filming at 24p, and after 10 minutes the video is 12 frames ahead that means that audio recorder is losing half a sec. every 10 minutes. Obviously you don't want to change the speed of the video, so you will speed up or slow down the audio recorded with audio editing program by the percent of change you have calculated. Note every time you start and stop filming with the DSLR you'll need to resync. I really can't imagine anyone would want to do this but everyone's pain tolerance is different.

Zhong Cheung · April 18th, 2011, 11:15 PM

Chris - sorry about that, Sony Vegas.

Peter - thanks for that informative reply!

Nigel Barker · April 18th, 2011, 11:16 PM

PluralEyes is the magic bullet (no relation) that simplifies synchronising audio & video in post. There is a version for most NLEs & a standalone version called DualEyes specifically designed for synchronising audio captured alongside DSLR video Singular Software - PluralEyes

Zhong Cheung · April 19th, 2011, 01:51 AM

Yup, thanks Nigel, I know all about PluralEyes, but my question was about audio drift syncing rather than straight up syncing. But apparently it has to do with the internal timers being different.

April 18th, 2011, 05:45 PM	#1
Zhong Cheung Major Player Join Date: Feb 2011 Location: North Hollywood, CA Posts: 202	Syncing Zoom H4N/H1/etc. Audio to 24p So many of us are using DSLRs/EVIL cameras to film weddings at 24p. However, many are also using external recorders such as the Zoom H4N or H1 to capture better audio than the onboard audio the camera can obtain. How do you sync this external audio with your 24p footage? For example, I'm hearing the Panasonic GH2 does not even shoot 1080p at 30fps, basically forcing you to choose 24p if you want to stick with 1080p. So, what is your process of syncing without causing audio drift?

April 18th, 2011, 06:02 PM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,366 Images: 513	Re: Syncing Zoom H4N/H1/etc. Audio to 24p What editing program are you using, so I know which NLE forum to move this to? __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

April 18th, 2011, 09:13 PM	#3
Pete Cofrancesco Inner Circle Join Date: May 2004 Location: USA Posts: 2,995	Re: Syncing Zoom H4N/H1/etc. Audio to 24p Audio drift isn't caused by the frame rate or resolution you film at, it only happens when the internal clock of the two devices is significantly different. Do a test by recording 10 minutes continuously with both devices starting and ending with a noise to measure the drift. If you are filming at 24p, and after 10 minutes the video is 12 frames ahead that means that audio recorder is losing half a sec. every 10 minutes. Obviously you don't want to change the speed of the video, so you will speed up or slow down the audio recorded with audio editing program by the percent of change you have calculated. Note every time you start and stop filming with the DSLR you'll need to resync. I really can't imagine anyone would want to do this but everyone's pain tolerance is different.

April 18th, 2011, 11:15 PM	#4
Zhong Cheung Major Player Join Date: Feb 2011 Location: North Hollywood, CA Posts: 202	Re: Syncing Zoom H4N/H1/etc. Audio to 24p Chris - sorry about that, Sony Vegas. Peter - thanks for that informative reply!

April 18th, 2011, 11:16 PM	#5
Nigel Barker Inner Circle Join Date: Feb 2009 Location: Norwich, Norfolk, UK Posts: 3,531	Re: Syncing Zoom H4N/H1/etc. Audio to 24p PluralEyes is the magic bullet (no relation) that simplifies synchronising audio & video in post. There is a version for most NLEs & a standalone version called DualEyes specifically designed for synchronising audio captured alongside DSLR video Singular Software - PluralEyes

April 19th, 2011, 01:51 AM	#6
Zhong Cheung Major Player Join Date: Feb 2011 Location: North Hollywood, CA Posts: 202	Re: Syncing Zoom H4N/H1/etc. Audio to 24p Yup, thanks Nigel, I know all about PluralEyes, but my question was about audio drift syncing rather than straight up syncing. But apparently it has to do with the internal timers being different.