Audio out of sync with Canon 7D

B

Ben_McElroy

Active member
I was finally able to start a project exclusively with the Canon 7D.

I shot about 7 interviews so far and while editing I noticed my footage is slightly out of sync with the reference audio from the 7D.

Just wondering if other people are noticing this? (I heard a rumor about this before so I guess it is actually true...)

I've been encoding all my footage to ProRes 422LT.
 
Well, it would help to know what frame rate you were shooting at, audio recorder, and so on. Do you mean your picture-from-7d is out of sync with the sound-from-7d after you convert the footage to ProRes? If so, how much?
 
Min is out of sync after converting with mpeg streamclip to prores. Looks like 3 frames off (audio ahead of video)
 
Mine is out of sync about that much.. i'm shooting 1920x1080 24p.
Once the video is encoded to ProRes, it's more noticeable. playing the clips in the viewer it doesn't look that bad, once its in final cut is where the problems occur.

ill try doing more tests.
 
Offhand, I'm guessing that the problem stems from converting 23.976 (as shot by the Canon) to 24.000. The 23.976 frame rate is to do with NTSC broadcast standards, you've got a small pulldown factor to deal with. Unless you are planning to go out to actual 35mm film at the end, keep everything at 23.976. See if ProRes gives you an option for 23.976, which it probably does.
 
Just to be clear - you're talking about audio from the camera...you are not running a seperate audio recorder (that's what I understood anyhow)

Either way, can't you jsut bump it back 3 frames to get it in sync?

I remember back in the day when the DVX first came out it had audio sync issues when shooting 24p, with the audio being 2 frames off the video.
 
You can bump it back but that sucks for 80 clips. Separate audio recorder matches original video in h.264 (perfect sync). convert video through mpeg streamclip (philip bloom's preferred method) off by 3 frames - I am going to see if there is a setting I am missing in the conversion- haven't run through compressor yet.
 
Ok it is an issue with my blackmagic intensity pro card feeding audio throught internal audio instead of HDMI - when I turn off the blackmagic output, everything is in sync.
 
soarprod said:
Ok it is an issue with my blackmagic intensity pro card feeding audio throught internal audio instead of HDMI - when I turn off the blackmagic output, everything is in sync.
Click to expand...

Ah - so they weren't out of sync after all... it was just a monitoring issue?
Good to know.
:thumbsup:
 
I convert mine through MPEG Streamclip and I get my audio from the camera about 2 frames out of sync, audio ahead of video. Hassle I don't like dealing with. I will try the advice to choose 23.9xx instead of 24 frames to see if that is the problem. Seems odd that would cause it though
 
I have the 2 second frame problem WITHOUT converting raw h264 AND still when i convert to pro res. Any ideas?!!?
 
Never met a DLSR in sync

Never met a DLSR in sync

Every DLSR I've ever worked with has been out of sync. Usually the audio is ahead 1 frame. Sometimes as much as 3 frames. I discourage people from using them as much as possible. They.are.not.professional.video.cameras! They don't know what time code is. The audio is out of sync. They record in h.264 with such heavy, lossy compression that if you start doing any color correction, your image completely falls apart once you start pushing the video.

Yes, they can make really pretty pictures, but if you don't have calibrated monitors and capture exactly what you want on location, you will regret not using a real professional video camera.
 
Try dropping the audio file from finder -> timeline
instead of finder -> project panel -> timeline

project panel will retime audio files to match easy setup

unless you have built your own custom prores easy setup then you risk retiming
 
Check to make sure your FCP sequence is set to 48khz in the capture preset BEFORE importing anything. Doesn't matter what capture preset it is, so long as it's 48khz. FCP has a very odd bug that will resample any audio upon import to whatever capture preset you have set, and it won't tell you it's doing this. It took me 3 days once to work this out, soon as I found out this weird thing was occurring I've never had a problem since.
 
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