24p sync issue on XL2

[Carlos Barbot]

Hey all new to the forums and to my XL2. Got a question. I was logging several bits of footage on FCP, and I noticed the audio was out of sync on the footage I shot in 24p -- on two separate tapes. Other footage was shot in 30p; no problems there. Haven't captured yet (waiting for new hard drive) so I don't know if its just a glitch on FCP or if the audio is truly out of sync. Anyone have this experience?

[Pete Bauer]

Hi Carlos, and welcome to DVinfo!

I'm not a FCP user, so can't help with the details of settings and so forth. But one possible cause for your trouble is a capture to a project with drop-frame timecode. The camera records the 24p footage as a 60i signal with nondrop-frame. The 24p footage must be captured and used in NONdrop-frame projects.

[Glenn Chan]

I don't think drop-frame versus non-drop-frame is the issue here? They are just different ways of counting timecode. DV as far as I know can only record drop-frame timecode, so a project using DF timecode is right. And the sync issues (if you mixed the two) would only crop up when you are doing EDLs or things like that.

2- Try checking to see if your project settings match your footage. Use the canned presets.

On your camera, check whether it was shot 12-bit (32khz sampling, 4-channels of audio) or 16-bit (48khz, 2 channels of audio). If you toggle the on-screen display functions it should show up. 16-bit audio is better quality and I would set your camera on that, unless you want 4 channels of audio (which Final Cut needs 2 passes to capture?; just avoid it).

[Carlos Barbot]

Hey guys thanks much for the responses-- and happy to be on the forums... now to the issue:

Originally Posted by Glenn Chan

I don't think drop-frame versus non-drop-frame is the issue here? They are just different ways of counting timecode. DV as far as I know can only record drop-frame timecode

I agree, time code isn't the issue. The camera can shoot in both modes. Specifically Drop for TV and Non-drop for Film x-fer. I shoot in drop frame... just because.

Originally Posted by Glenn Chan

Try checking to see if your project settings match your footage. Use the canned presets.

OK. All the footage is shot 16:9. So I checked the A/V settings on FCP and the sequence preset was DV NTSC 48 kHz and the capture preset was DV NTSC 48 kHz Anamorphic. But that's because I wanted to be able to put both 16:9 and 4:3 footage into the same sequence w/out distortion. But do you think it makes difference? I mean I haven't captured anything-- all I was doing was logging.

Originally Posted by Glenn Chan

On your camera, check whether it was shot 12-bit (32khz sampling, 4-channels of audio) or 16-bit (48khz, 2 channels of audio)

Yeah I always make sure I'm shooting w/ 16-bit. But I do know that you can have serious problems later on if you try to put 12-bit and 16-bit audio into a project on AVID. It won't do it. Apparently FCP is much more forgiving!

[Glenn Chan]

Something else you could try:
Right click the clip and get properties on it.

Is the audio sampling rate EXACTLY 48.000khz? Some cameras like the old XL1 were slightly off, with the XL1 being pretty bad (somewhere around 48.007-48.009khz). If that is the case, you need to configure "sync adjust movie" (SAM) correctly.

I figure they would've fixed that problem by now...

2- Is there any point in the clip where there is no audio? (i.e. you unplugged a microphone) I have heard that SAM will work incorrectly in that case and cause a loss of sync or something like that.

[Carlos Barbot]

Originally Posted by Carlos Barbot

I agree, time code isn't the issue. The camera can shoot in both modes. Specifically Drop for TV and Non-drop for Film x-fer. I shoot in drop frame... just because.

Originally Posted by Pete Bauer

But one possible cause for your trouble is that a capture to a project with drop-frame timecode. The camera records the 24p footage as a 60i signal with nondrop-frame. The 24p footage must be captured and used in NONdrop-frame projects.

Hey Pete, after responding to your post before I thought about it a little longer and realized I, in my newbie arrogance had probably just, given away my ignorance by saying "I shoot in drop frame... just because." It turns out you ARE right that 24p footage must be shot in non-drop.

(http://www.editorsguild.com/newslett...4p_primer.html)

But alas it's not the problem: The XL2 will not allow you to shoot in drop- frame when in 24p. So even though my original settings on the camera were for drop frame TC, once I switched the camera to shoot in 24p, it locked out the option and only lets me record rec-run or free run.

So apologies for skipping over your observation before. Now I know something I did not know. :)

[Pete Bauer]

Yeah, that's the camera side of 24p: nondrop. I'll have to leave it for FCP users to figure out if audio drift can be caused by switches between nondrop and drop within the software. I have no way to know if timebase behavior in FCP might be inconsistent between audio and video for the 24p / 24pA schemes -- or not. So it isn't the camera, but the software settings that need to be checked.

Fingers crossed that it all gets sorted out quickly!