Syncing separate audio & 5D video at DVinfo.net

Jeremy Nicholl · June 6th, 2009, 11:32 AM

Does anyone have any clever tricks for syncing audio & video when going dual system to replace the 5D audio track when you don’t have the luxury of clapper boards etc? In other words, pure run and gun, no chance to prep, you just have to fix it in post.

I tried it today, my theory being that I could just sync the wave-forms, then replace the 5D audio. Of course I’d never bothered to look at a 5D wave-form before: the AGC turned everything into an almost indistinguishable mess. Nonetheless I did find it pretty quick and easy to sync the video and audio after a bit of to and fro in the timeline.

But that was a first try and I’m assuming it was beginner’s luck and that when I really need to do this on a deadline it will be a different story.

So what’s the secret[s]?

Nigel Barker · June 6th, 2009, 12:14 PM

This FCP plugin PluralEyes™ magically does it for you apparently.

Jon Fairhurst · June 6th, 2009, 12:20 PM

I think the hard part is getting a rough match, if you have a lot of video and audio. I do this by watching and listening. Once you find the rough match, just find a word with a hard consonant or peak and line up those waveforms. Anything within 40ms is acceptable, and within 10ms is excellent.

Jim Newberry · June 6th, 2009, 06:46 PM

A simple hand clap in front of the camera, preferably at head and tail of scene helps a lot. If you have an iPhone, there's a slate app (with an animated clapboard that makes an audible clap). Also you need to make sure that your separate audio track is running at the same speed...

Jon Fairhurst · June 7th, 2009, 01:12 AM

Quote:

Originally Posted by Jim Newberry

A simple hand clap in front of the camera, preferably at head and tail of scene helps a lot.

By using the audio in the camera, it doesn't even have to be in front of the camera. I've verified that the 5D2 mic is well synchronized to the video. If you match the peaks from the two waveforms, it will be sync'd to the video. Also, the most accurate that you can get the sync visually is 33ms (1/30.) By sync'ing to the 5D2 audio, you can get it spot on.

Keep in mind that sound travels at about 1ms per foot, in case your camera (and the built-in mic) is far from the talent.

Brian Luce · June 7th, 2009, 01:58 AM

Quote:

Originally Posted by Jon Fairhurst

By using the audio in the camera, it doesn't even have to be in front of the camera. I've verified that the 5D2 mic is well synchronized to the video. If you match the peaks from the two waveforms, it will be sync'd to the video. Also, the most accurate that you can get the sync visually is 33ms (1/30.) By sync'ing to the 5D2 audio, you can get it spot on.

Keep in mind that sound travels at about 1ms per foot, in case your camera (and the built-in mic) is far from the talent.

Oh. Well that's obvious and simple enough then. Built in audio as guide track.

Ryan Mueller · June 7th, 2009, 08:46 AM

When shooting run-n-gun, I have been mounting my H4n to the hot shoe of the cam. I roll the cam, then the speed (audio) and snap my fingers close to the mics. Gives me a nice peak that I can look for in the waveforms. Easy as pie!

Jeremy Nicholl · June 7th, 2009, 09:41 AM

Quote:

Originally Posted by Ryan Mueller

When shooting run-n-gun, I have been mounting my H4n to the hot shoe of the cam. I roll the cam, then the speed (audio) and snap my fingers close to the mics. Gives me a nice peak that I can look for in the waveforms. Easy as pie!

Yes, I tried exactly the same thing this morning and it works brilliantly. So the 5D audio track serves a purpose after all.

Evan Donn · June 8th, 2009, 10:45 AM

Pluraleyes does a great job, used it for the first time over the weekend and it synced up 30+ audio clips from an H4 with the corresponding video clips without a problem (had to change the audio speed on all the clips to maintain sync, but that's the case with any solution).

June 6th, 2009, 11:32 AM	#1
Jeremy Nicholl Regular Crew Join Date: Mar 2007 Location: Moscow, Russian Federation Posts: 50	Syncing separate audio & 5D video Does anyone have any clever tricks for syncing audio & video when going dual system to replace the 5D audio track when you don’t have the luxury of clapper boards etc? In other words, pure run and gun, no chance to prep, you just have to fix it in post. I tried it today, my theory being that I could just sync the wave-forms, then replace the 5D audio. Of course I’d never bothered to look at a 5D wave-form before: the AGC turned everything into an almost indistinguishable mess. Nonetheless I did find it pretty quick and easy to sync the video and audio after a bit of to and fro in the timeline. But that was a first try and I’m assuming it was beginner’s luck and that when I really need to do this on a deadline it will be a different story. So what’s the secret[s]?

June 6th, 2009, 12:20 PM	#3
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	I think the hard part is getting a rough match, if you have a lot of video and audio. I do this by watching and listening. Once you find the rough match, just find a word with a hard consonant or peak and line up those waveforms. Anything within 40ms is acceptable, and within 10ms is excellent. __________________ Jon Fairhurst

June 8th, 2009, 10:45 AM	#9
Evan Donn Major Player Join Date: Feb 2006 Location: Philadelphia Posts: 795	Pluraleyes does a great job, used it for the first time over the weekend and it synced up 30+ audio clips from an H4 with the corresponding video clips without a problem (had to change the audio speed on all the clips to maintain sync, but that's the case with any solution). __________________ My latest short documentary: "Four Pauls: Bring the Hat Back!"

June 6th, 2009, 12:14 PM	#2
Nigel Barker Inner Circle Join Date: Feb 2009 Location: Norwich, Norfolk, UK Posts: 3,531	This FCP plugin PluralEyes™ magically does it for you apparently.

June 6th, 2009, 06:46 PM	#4
Jim Newberry Regular Crew Join Date: May 2007 Location: Los Angeles, California Posts: 170	A simple hand clap in front of the camera, preferably at head and tail of scene helps a lot. If you have an iPhone, there's a slate app (with an animated clapboard that makes an audible clap). Also you need to make sure that your separate audio track is running at the same speed...

June 7th, 2009, 08:46 AM	#7
Ryan Mueller Major Player Join Date: Mar 2007 Location: Highlands Ranch, CO Posts: 336	When shooting run-n-gun, I have been mounting my H4n to the hot shoe of the cam. I roll the cam, then the speed (audio) and snap my fingers close to the mics. Gives me a nice peak that I can look for in the waveforms. Easy as pie!