sync drift: which FCP setup for 23.98? at DVinfo.net

Jim Newberry · July 23rd, 2011, 11:51 AM

I've been using a Zoom H4N with my 5DMII, and syncing with PluralEyes in FCP 6. I've shot a bunch of stuff and been able to get good sync. Recently though, I'm having an issue where after running PE the start of every clip is synced, but then it drifts. I've tried the 99.9% speed adjustment to the Zoom audio tracks to no avail.

I used to use the Canon 5D easy setup, but that's for 30fps and now I'm shooting at 24. What's the best easy setup for this?

I have read this article: 25 Hour Day: DSLR Dual-System Audio: The 99.9% Solution

More details:

I'm shooting at 24fps (actually 23.98, right?)
Converting to ProRes via the Canon FCP plugin
Recording stereo audio on the Zoom at 48K, 16-bit (5D is recording at 48K as well)
I first drag my ProRes video clips to the timeline, then the Zoom audio clips
Run ProRes
Sync is perfect at start of each clip but drifts

Any suggestions would be appreciated.

Bill Pryor · July 23rd, 2011, 03:57 PM

I use MPEG Streamclip, not the plug-in, but with Streamclip there's a menu setting for audio. It defaults to automatic, but I always set it to 48khz. It could be that your audio is coming in during the conversion at 44. Not sure if that would do it, but it's something to check. I'm getting really eager to finalize my switch to Adobe CS5.5 so I won't have to transcode anymore.

Jim Newberry · July 23rd, 2011, 04:17 PM

Thanks for the reply. I checked the Zoom files and video clips in the Finder, and they both show as 48K. Same when I check the properties of the audio and vid clips in their bin in FCP--everything's 48K, including the sequence. And vid clips and sequence show as 23.98.

Bill Pryor · July 23rd, 2011, 06:51 PM

Weird. Another thought is that maybe the computer is not playing the timeline properly. You might try grabbing a portion of a clip that's clearly out of sync, export it as a QT and see how it plays on another computer. But if this is something that's just started, it seems to me to imply that something could be wrong with the recorder. Have you played the clip with just your camera reference audio? I'd look at that and see if it's in sync. If not, that would imply a problem with the camera. If it is in sync and it's the Zoom track that drifts, then it seems likely it would be the recorder. But I'm just speculating here; it's not something I've run across.

One thing that happens to me is that I have to make 1280x720 WMV compressions for a client. They don't play in sync on the Mac, but when I put them on a jump drive and play on any PC in the office, they are fine. Also, when I was editing on a 17" MacBook Pro, it wouldn't always play clips without stuttering, and things would look out of sync that weren't. I'd check a clip on another system first thing. Try to eliminate one thing at a time.

Daniel Weber · July 23rd, 2011, 10:47 PM

Quote:

Originally Posted by Jim Newberry

I've been using a Zoom H4N with my 5DMII, and syncing with PluralEyes in FCP 6. I've shot a bunch of stuff and been able to get good sync. Recently though, I'm having an issue where after running PE the start of every clip is synced, but then it drifts. I've tried the 99.9% speed adjustment to the Zoom audio tracks to no avail.

This is a known problem with the Zoom recorder. I have noticed it with files shot with my Canon 7D. I have now gone to the Tascam DR-100 which doesn't seem to have the audio drift problem.

Now I did shoot an interview with the 7D and the Zoom the other day and didn't have any drift problems. I am shooting everything at 29.97.

Daniel Weber

Bill Pryor · July 24th, 2011, 09:58 AM

Interesting. I've used a Zoom for about 2 years and haven't seen any drift. It could be a manufacturing tolerance issue--some good, some not good.

I've always felt the Zoom H4N's quality was good, but there are some things I've not liked about it. Recently the mini headphone jack died. I'm trying to get it repaired, but needed a new recorder for several shoots. I bought the Marantz PMD661 which also has a 1/4"-20 socket on the bottom to mount on the camera rig. It's twice the price of the Zoom, a bit heavier, and about an inch wider, a little longer. It's a lot closer to being a professional recorder and the sound quality seems better. More of a richer sound, fuller...not sure how to describe that.

Still, I never had a sync issue with the Zoom. But now that you mention the issue, the original poster said the problem only started recently. With that in mind it would be good if he could find another Zoom and do a test to isolate the issue. The only other thing that comes to mind would be the SD card...I wonder if it's possible for a card to be too slow or something and cause a problem. Doesn't sound likely, but I always try to check everything.

Doesn't Plural Eyes create new files? One more thing to check would be to sync a clip manually and see if it makes any difference. As I said, I try everything.

Evan Donn · July 25th, 2011, 10:50 PM

My guess is you've still got the timebase in the FCP easy setup somehow at 30 instead of 29.97 from using the old easy setup - I had this problem as well. The problem is once it's screwed up for a project you can't just change it anywhere from within FCP and fix it - you need to create a new project with a proper timebase before importing your footage. There is actually a way to change existing projects - it involves exporting to XML and doing a find/replace on the tags that define the timebase for the audio, but I don't remember to exact tag you need to look for, and it's probably easier to create a new project from scratch if you haven't started editing yet.

July 23rd, 2011, 11:51 AM	#1
Jim Newberry Regular Crew Join Date: May 2007 Location: Los Angeles, California Posts: 170	sync drift: which FCP setup for 23.98? I've been using a Zoom H4N with my 5DMII, and syncing with PluralEyes in FCP 6. I've shot a bunch of stuff and been able to get good sync. Recently though, I'm having an issue where after running PE the start of every clip is synced, but then it drifts. I've tried the 99.9% speed adjustment to the Zoom audio tracks to no avail. I used to use the Canon 5D easy setup, but that's for 30fps and now I'm shooting at 24. What's the best easy setup for this? I have read this article: 25 Hour Day: DSLR Dual-System Audio: The 99.9% Solution More details: I'm shooting at 24fps (actually 23.98, right?) Converting to ProRes via the Canon FCP plugin Recording stereo audio on the Zoom at 48K, 16-bit (5D is recording at 48K as well) I first drag my ProRes video clips to the timeline, then the Zoom audio clips Run ProRes Sync is perfect at start of each clip but drifts Any suggestions would be appreciated.

July 23rd, 2011, 03:57 PM	#2
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	Re: sync drift: which FCP setup for 23.98? I use MPEG Streamclip, not the plug-in, but with Streamclip there's a menu setting for audio. It defaults to automatic, but I always set it to 48khz. It could be that your audio is coming in during the conversion at 44. Not sure if that would do it, but it's something to check. I'm getting really eager to finalize my switch to Adobe CS5.5 so I won't have to transcode anymore.

July 23rd, 2011, 04:17 PM	#3
Jim Newberry Regular Crew Join Date: May 2007 Location: Los Angeles, California Posts: 170	Re: sync drift: which FCP setup for 23.98? Thanks for the reply. I checked the Zoom files and video clips in the Finder, and they both show as 48K. Same when I check the properties of the audio and vid clips in their bin in FCP--everything's 48K, including the sequence. And vid clips and sequence show as 23.98.

July 23rd, 2011, 06:51 PM	#4
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	Re: sync drift: which FCP setup for 23.98? Weird. Another thought is that maybe the computer is not playing the timeline properly. You might try grabbing a portion of a clip that's clearly out of sync, export it as a QT and see how it plays on another computer. But if this is something that's just started, it seems to me to imply that something could be wrong with the recorder. Have you played the clip with just your camera reference audio? I'd look at that and see if it's in sync. If not, that would imply a problem with the camera. If it is in sync and it's the Zoom track that drifts, then it seems likely it would be the recorder. But I'm just speculating here; it's not something I've run across. One thing that happens to me is that I have to make 1280x720 WMV compressions for a client. They don't play in sync on the Mac, but when I put them on a jump drive and play on any PC in the office, they are fine. Also, when I was editing on a 17" MacBook Pro, it wouldn't always play clips without stuttering, and things would look out of sync that weren't. I'd check a clip on another system first thing. Try to eliminate one thing at a time.

July 24th, 2011, 09:58 AM	#6
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	Re: sync drift: which FCP setup for 23.98? Interesting. I've used a Zoom for about 2 years and haven't seen any drift. It could be a manufacturing tolerance issue--some good, some not good. I've always felt the Zoom H4N's quality was good, but there are some things I've not liked about it. Recently the mini headphone jack died. I'm trying to get it repaired, but needed a new recorder for several shoots. I bought the Marantz PMD661 which also has a 1/4"-20 socket on the bottom to mount on the camera rig. It's twice the price of the Zoom, a bit heavier, and about an inch wider, a little longer. It's a lot closer to being a professional recorder and the sound quality seems better. More of a richer sound, fuller...not sure how to describe that. Still, I never had a sync issue with the Zoom. But now that you mention the issue, the original poster said the problem only started recently. With that in mind it would be good if he could find another Zoom and do a test to isolate the issue. The only other thing that comes to mind would be the SD card...I wonder if it's possible for a card to be too slow or something and cause a problem. Doesn't sound likely, but I always try to check everything. Doesn't Plural Eyes create new files? One more thing to check would be to sync a clip manually and see if it makes any difference. As I said, I try everything.

July 25th, 2011, 10:50 PM	#7
Evan Donn Major Player Join Date: Feb 2006 Location: Philadelphia Posts: 795	Re: sync drift: which FCP setup for 23.98? My guess is you've still got the timebase in the FCP easy setup somehow at 30 instead of 29.97 from using the old easy setup - I had this problem as well. The problem is once it's screwed up for a project you can't just change it anywhere from within FCP and fix it - you need to create a new project with a proper timebase before importing your footage. There is actually a way to change existing projects - it involves exporting to XML and doing a find/replace on the tags that define the timebase for the audio, but I don't remember to exact tag you need to look for, and it's probably easier to create a new project from scratch if you haven't started editing yet. __________________ My latest short documentary: "Four Pauls: Bring the Hat Back!"