audio and video dont sync

B

bus33

Member
After importing my footage (24p) and the audio for an olympus LS-10 into FCP they dont sync up when i put them in the timeline together. I can get them to start together but i think the video is a little faster than the audio and they start to pull away from each other. I've also tried to sync up audio from a soundboard mix and have had the same results. I'm not sure if its a capturing problem, camera maybe recording fast problem, or both.

thanks in advance for any help
 
bus33 said:
After importing my footage (24p) and the audio for an olympus LS-10 into FCP they dont sync up when i put them in the timeline together. I can get them to start together but i think the video is a little faster than the audio and they start to pull away from each other. I've also tried to sync up audio from a soundboard mix and have had the same results. I'm not sure if its a capturing problem, camera maybe recording fast problem, or both.

thanks in advance for any help
Click to expand...

Fear not. This is to be expected when using a non-sync, non-TC devics for double system sound. Because the Olympus is not clocked accurately with the camera, there will be a drift.

Take your audio and time-compress it to 99% of it's original duration and you should be fine.
 
thanks for responding so quick. is there any way to sync them so i don't have to adjust anything in FCP? i did the 99% and it helped but it was still a little off. its a gradual split between the vid and sound. it keeps getting more off the further along it goes.
 
bus33 said:
thanks for responding so quick. is there any way to sync them so i don't have to adjust anything in FCP? i did the 99% and it helped but it was still a little off. its a gradual split between the vid and sound. it keeps getting more off the further along it goes.
Click to expand...

You should use a clapper to mark the beginning of the shot. Then slide the audio to match the clapper sync frame. There is a way to 'edit' audio at the sub frame level, but since I've not needed to do that, I've forgotten, but I think when you have the audio clip in the preview window, you can get down to 100ths of a second resolution. I'm not in a possition to bring up FC (in my case Express) to give specific details.

If you audio is longer than a minute or two, you may have to readjust further down the time line.

Did you record at 48k samples/second ? or some other speed.
 
A little off over what kind of time period? 2 minutes? 20 minutes?
Also, check all your device settings to see if there is a sample rate or frame rate difference.
Is the LS-10 recording at 48K or 44.1K?
Are your import settings exactly correct for what you shot at?
Is the LS-10 audio faster or slower than the video audio?

~DPS
 
It's over a long period. Its a wedding ceremony. the first guy told me to put it at 99% but it still got a little off. After playing around with the speed it was actually 99.9% not just 99% that worked. The Ls-10 was faster so i lowered the speed of the video to finally sync up. the ls-10 was recording at 44.1. if it was at 48 would it have recorded at a different speed?
 
bus33 said:
It's over a long period. Its a wedding ceremony. the first guy told me to put it at 99% but it still got a little off. After playing around with the speed it was actually 99.9% not just 99% that worked.
Click to expand...

99% is a starting point. The drift will start to be noticeable within a few minutes of constant play. Most recorders (cameras, handheld recorders, etc.) don't record at the exact, nominal sample rate. There's an ever-so-slight variation and two independent devices won't have the same exact value.

bus33 said:
The Ls-10 was faster so i lowered the speed of the video to finally sync up.
Click to expand...

You really need adjust the audio speed rather than the video speed. You won't hear artifacting in the audio with a speed adjustment that minor, but video speed adjustments will show up much sooner.

bus33 said:
the ls-10 was recording at 44.1. if it was at 48 would it have recorded at a different speed?
Click to expand...

DV records at 48k, so your LS-10 should be set to record at 48k. Period. But even if you had recorded at 48k, there'd still be a drift just because they aren't clocked together. Generally, I find that the handheld recorders run slightly slower than DV.

You need to convert your audio to 48k before you start editing with it.
 
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