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Audio sync drift problem with HVX200 P2 capture

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Damon Packard
Audio sync drift problem with HVX200 P2 capture
on Jul 2, 2010 at 9:33:13 pm

I'm not sure if this is a question for the Panasonic HVX200 board or FCP board but..last night a friend brought me some footage to capture and i encountered a baffling technical glitch i've never encountered before with that camera.

Footage was shot 720 30p, capture and project settings were all matched, the footage was fine and IN SYNC when played back ON the camera, but when and after capturing it drifted out of sync

Regardless of which method i used to capture/import the footage into FCP (trying it on three different computers no less) The audio would drift out of sync almost instantly, though very randomly and erratically at times with various clips. Meaning sometimes a clip would capture and it would hold in sync for a minute then drift out, sometimes drift out of sync after 3 seconds!

I tried capturing both ways (via FW and USB 2.0) and the play-back streaming method (via FW) on both FCP 6 and 7 on a G5, Intel MiniMac and Intel Promac. Sound sync would always drift. The sound was always 'faster' than the image

Has anyone ever encountered this before?? Any idea's? One theory was that the camera settings in recording format and shutter speeds were somehow mismatched or improper but would that cause audio to drift after a capture??




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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Jul 2, 2010 at 11:10:04 pm

Why not just take the footage off of the p2 cards?


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Damon Packard
Re: Audio sync drift problem with HVX200 P2 capture
on Jul 3, 2010 at 4:52:00 am

well,..that's what i'm trying to do


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Jul 3, 2010 at 6:05:50 am

So tell me exactly what you did. Camera menus and everything. From your post, it's not quite adding up. No offense, just helping.


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Damon Packard
Re: Audio sync drift problem with HVX200 P2 capture
on Jul 3, 2010 at 8:59:22 am

Yea there may have been something in the camera settings that was off, like frame rate, recording settings i'm not sure. It was shot in 720, 30p (regular not native) thats all i know (i didn't shoot the footage) But i've never encountered a situation where audio drifted after capturing, it's really baffling. Personally i've shot tons of footage on the same model camera and haven't always been careful about matching frame-rate/format settings and all that jazz and it was always ok

My only guess is it's some bizarre glitch no human has ever encountered


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Jul 3, 2010 at 2:25:43 pm

So you have the footage transferred off of the cards?

Please give me the play by play.


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 3:42:30 pm

Damon,

I don't know if you solved your problem, but I have a similar baffling issue. I have 23.98 footage shot on both the 7D and T2i, transcoded to one long clip using MPEG Streamclip. When I play the transcoded clip in QT or in the Finder, it's perfectly fine. When I drag and drop it into FCP, then play it in the Viewer, the audio drifts. This only happens with footage that is 23.98. I transcoded those original files to 29.97 (even though they were shot in 23.98) and the resulting file did NOT drift.

What's weirder is that I have some other 23.98 files which also do NOT drift. Those are clips I created earlier in the year. I can't find a consistent pattern. I've tried numerous clips and dozens of tests and can't nail down a consistent source. The closest thing I can determine that it's 23.98 footage created after a certain date.

I've posted on the Cow and a few other forums, and no one can figure it out. Your problem seems like the same issue I'm having. At least I'm not alone.

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 3:43:51 pm

[Ron Dawson] "When I play the transcoded clip in QT or in the Finder, it's perfectly fine. When I drag and drop it into FCP, then play it in the Viewer, the audio drifts. "

Is this embedded or separate audio? You have transcoded the file to 23.976 not 23.98, right? There's a big difference.

Jeremy


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 3:52:06 pm

Hi Jeremy,

I transcoded the clip to 23.98. That's what I've always done and have never experienced this. It's the most baffling thing.

Here's my latest update: I discovered that 29.97 footage does not drift when imported into FCP. I transcoded the original h.264 files (shot at the 1080 24 on the 7D) and this time transcoded them to 29.97, and the drifting does not occur. The downside is that I don't want 29.97 footage, I want 23.98.

I would make the conclusion that 23.98 footage is the culprit, except that there are SOME 23.98 clips I have which are also fine (i.e. don't drift). But, somehow the drifting seems tied to 23.98 footage shot after a certain date.

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 3:55:46 pm

Should always be 23.976. 23.98 is shorthand for that in FCP.

Again, is this separate audio or embedded?


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 4:47:45 pm

Thanks for the transcoding tip. Will definitely keep that in mind.

Anyhoo, it is embedded audio. Clip plays fine when played in QT or the Finder. Once imported into FCP and I play in the Viewer, I get the drift. Gets progressively worse as you get to the end of the file. The longer the file, the worse the drift gets. For one 3.5 hour file it's as much as 22 frames.

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 4:49:13 pm

Well, there could be a lot of reasons for this. For now we will focus on frame rate.

I'd try another transcode of the media with 23.976 set as your frame rate, not 23.98.

Jeremy


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 5:17:35 pm

I'm way ahead of you Jeremy (well, maybe not that way ahead of you. :) I am currently transcoding some clips at 23.976 that I originally transcoded at 23.98. We'll see if the addresses the audio drift issue. It is a promising theory. If 23.98 is not the real frame rate that FCP recognizes (despite the fact it says 23.98 in the sequence settings, etc.), that could explain it. Especially since clips encoded at 29.97 work fine.

stay tuned...

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 5:20:24 pm

[Ron Dawson] "If 23.98 is not the real frame rate that FCP recognizes (despite the fact it says 23.98 in the sequence settings, etc.)"

I know that FCP says 23.98, and in my opinion, it is not a smart move. The real frame rate is 23.976, even though FCP calls it 23.98 (like I said, it's shorthand in FCP for 23.976). It really does mean 23.976 and FCP will act normally if your movies are 23.976.

If you have After Effects, you can render a 23.98 and a 23.976 movie and you will see that FCP doesn't handle 23.98 movies properly.

If this doesn't work, we will try other things.

Jeremy


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 7:36:27 pm

HALLELUJAH! EUREKA! LAND HO! Jeremy I could kiss you! No kidding. That did it! I re-encoded two of the problem clips and dialed them in specifically at 23.976 (whereas before I did it specifically at 23.98). Both clips when dragged and dropped into FCP play fine. These were both shorter clips so I'm going to re-transcode the very first problem clip which was over an hour. But, based on these two tests, I think I can officially call you my hero.

When I think about the other "23.98" clips I have that didn't experience the problem, my guess is that when I created those with MPEG Streamclip, I left the frame rate box empty (which is what I normally used to do). So, the original h.264 files must have just defaulted to their actual 23.976 frame rates. Only recently did I start actually typing in 23.98 into the frame rate field in MPEG streamclip.

If I'm ever in Chi-town again, I owe you a drink! Thanks again.

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 7:41:56 pm

[Ron Dawson] "When I think about the other "23.98" clips I have that didn't experience the problem, my guess is that when I created those with MPEG Streamclip, I left the frame rate box empty (which is what I normally used to do)."

On shorter clips, you probably just don't notice the drift. The difference between 23.976 and 23.980 is very small. On shorter clips, this difference own't show up to the eye and on longer clips you will notice this drift as the time will add up. FCP might not play the 23.98 clips back correctly though, so it's is protocol to put the clips in the proper frame rate of 23.976.

Also, to help you in the future, you might want to look at Grinder or the free Log and Transfer plugin from Canon. Both of those solutions will handle any frame rate shenanigans for you.

Glad you're up and running. ;)

Jeremy


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 7:55:02 pm

Actually, on these two shorter clips (49 min and 21 min respectively) I still did notice the drift. It was obviously much more pronounced on the longer hour+ long clips.

I'll take a look at the plugins you suggest.

Thx again.

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 11, 2010 at 7:56:16 pm

[Ron Dawson] "Actually, on these two shorter clips (49 min and 21 min respectively)"

Those are long clips! When I say short, I mean 1 minute or less.

Jeremy


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Arthur Vincie
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 17, 2010 at 4:16:24 pm

I appear to be having a related problem. However, I've used all the techniques outlined above and still have internal sync consistency issues.

The source material is clips from a feature film shot on the Canon 5D Mk2 with the latest firmware update. We used a slate with a traditional clapper to sync up to separate-source audio. HOWEVER, I'm not even at the point of syncing yet. I'm noticing this problem with the clip itself.

Format: 1920x1080 23.976fps progressive
Transcoded to: ProRes (LT)
Using: Canon plug-in (latest version) for Final Cut Pro
Software: Final Cut 7.0.3, Mac OSX 10.6.4
Hardware: 2x 2.4 GHz 8-Core, 8 Gigs of RAM, 2TB internal editing drive, 2 TB E-SATA drive (for backing up camera masters)

The FCP sequences are all running at 23.976fps. The clips (as far as I can tell) were transcoded properly at 23.976.

When playing the clip both in the Viewer AND in a 23.976 sequence, the slate is ALWAYS off by one-to-two frames. However, using plosives as a guide (dialog "p"s and "b"s), it appears as though the clips SOMETIMES drift. Plosives can be unreliable (especially if it's a wide shot).

Please keep in mind:
I'm talking about the CAMERA AUDIO in the clip, NOT another audio source. In other words, the clip IS NOT SYNCED TO ITSELF.

The clips are short (4-5 minutes at the long end). They are consistently off (by 1-2 frames) at the top of the clip. I've tried adjusting the playback offset but that doesn't seem to make any difference. The slates are generally well-done (they aren't half out of the frame or being moved while being clapped), certainly enough to tell when they're closed.

Any suggestions? I'd love to not have to retranscode everything. Thank you very much.

Sincerely,

Arthur Vincie
Director, "Found In Time"
http://www.foundintimefilm.com
http://www.chaoticsequence.com


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 17, 2010 at 9:21:34 pm

Hi Arthur,

You wrote that the clips were transcoded properly "as far as you can tell." What does that mean? Is there any chance they WERE transcoded at 23.98 instead of 23.976?

The other question is, does the audio drift get progressively worse, or is it exactly off by 2 frames all throughout?Lastly, is the clip out of synch when played in the Finder or in QuickTime? If so, then at least you know it's a problem with the clip. If, as it was in my case, you only notice the synch issue within FCP, then you know it's an issue with how FCP is interpreting the clip, and something needs to be changed with how you created it that will make FCP "happy."

Good luck!

~ Ron

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Arthur Vincie
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 20, 2010 at 6:58:42 pm

"As far as I know" - means just that. FCP says "23.98" as the timecode base for the clip video and audio, but that doesn't mean anything, since it's shorthand for 23.976.

I've played the clips in QT and the problem remains the same. However, it's a little harder to check since there's no way to scrub video AND audio one frame at a time in QT (you can advance/retreat by one frame but the audio doesn't play, unless there's a control I'm not aware of).

My clips are fairly short, but they do seem to stay exactly 2 frames off (I've encountered a few clips that are exactly 1 frame off, though I'm not sure what that means). If there is a drift it's so subtle that it's not cropping up in the 2-3 mins. average length of the clips.

The Canon E1 plugin for FCP didn't give me any choice as to framerate, but since it was made by Canon specifically for Canon 5D footage I'm assuming (maybe a bad assumption) that they've thought of the framerate discrepancy.

Have checked with some other editors and my DP and they're looking into both my footage and the problem in general. Could be a camera issue.

When sliding the audio a frame forward it syncs up fine, so I've proceeded with my logging in the meanwhile. Just hoping I'm not overlooking something that will bite me in the butt later on.


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Jeremy Garchow
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 17, 2010 at 11:03:39 pm

[Arthur Vincie] "I'm talking about the CAMERA AUDIO in the clip, NOT another audio source. In other words, the clip IS NOT SYNCED TO ITSELF."

Is the h264 file in sync?


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Arthur Vincie
Re: Audio sync drift problem with HVX200 P2 capture
on Oct 20, 2010 at 6:51:22 pm

The H.264 file suffers from the same problem (audio slate is one/two frames off from visual clapper) - when playing back in FCP. You can't really scrub in QT frame-by-frame AND check audio, so again I'm not sure if this is an FCP issue or a footage issue. I've asked my DP to check his camera settings.

The audio doesn't seem to drift from the front to the end of the clip, though if it was a really slight drift I probably wouldn't notice it since the clips are relatively short (5 minutes is long).


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Jeff Sandmann
Re: Audio sync drift problem with HVX200 P2 capture
on Nov 24, 2010 at 4:42:20 am

Ron,

I'm having pretty much the exact same problem you were having in October. I'm bringing in 1080i 24p clips from a Panasonic HPX-300. When I look at the clip in QT on my machine the audio syncs fine. It's only when I get them in FCP that I get the audio drift.

It sounds like Jeremy helped you with your problem which basically had to do with somehow converting your footage from 23.98 to 23.976. I'm thinking that would work for me to, but my question to you is;
How do you go about doing that? You talk about transcoding your footage but I'm not sure I follow what that's all about. What program are you using?

Thanks,
Jeff


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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Nov 24, 2010 at 8:18:32 pm

Hey Jeff

I use MPEG Streamclip to transcode my DSLR h.264 footage to a format the I can edit in FCP. I use ProRes format. As long as I don't enter any specific frame rate in MPEG streamclip, it'll default to the clip's natural frame rate of 23.976. My problem before was that I was specifically entering the frame rate 23.98. That was causing the problem in FCP.

Not sure how you use your footage, but you were calling it 1080i 24p. That's kind of an oxymoron. Either it's 1080p at 24 fps, or it's 1080i. I don't think that's your problem per se, just pointing that out.

Are you able to use footage out of the HPX in its native format, or do you need to transcode it first? If the latter, whichever program you use, either leave the frame rate field blank, or specifically enter the exact frame rate of your footage, which in this case sounds like 23.976.

Hope that helps.

~ Ron

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Cuauhtzin Gutierrez
Re: Audio sync drift problem with HVX200 P2 capture
on Aug 28, 2011 at 9:39:16 pm

Hello,

I know this post is about a year old but the original issue was never solved and I'm having the same problem. Footage was shot on an HVX at 30p and after everything was captured off the P2 card the audio is out of sync. If I play the clips back on the camera, the audio is in sync and perfectly normal. Trying to play the captured clips in QT and FC shows the audio is off.

I have a few interviews and all of them are out of sync. It seems like the audio drifts further out of sync as the clip progresses. I try to line up the audio (about 20 frames) and it appears to be in sync for short while, but as the clip keeps playing it goes out of sync again.

Does anybody know what the problem could be? Thank you in advance.



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Ron Dawson
Re: Audio sync drift problem with HVX200 P2 capture
on Aug 29, 2011 at 1:28:37 am

Hi,

This problem was solved for me on Creative Cow. I don't know if this is your same solution, but this was what happened with me:

I was having the same problem you described. Exactly! (drifting getting worse as the clip progressed, etc.) It turns out the problem was that when I transcoded the 24p footage (shot on a DSLR) in mpeg stream clip, I manually set as the frames per second to exactly 23.98. I did this b/c in FCP, that is the short-hand used for 24p footage. However, the footage is really 23.976. Even in FCP, it really is 23.976, despite the fact that is says 23.98 all throughout.

The problem is this: if you drop footage into FCP that is at a frame rate that is not recognized by FCP (e.g. 23.98 vs. 23.976), you get the drift.

I solved the problem by leaving the fps field in mpeg streamclip blank. By doing that, mpeg streamclip will transcode the footage at the source material frame rate, which is actually 23.976.

You didn't mention that you were transcoding, so my guess is that the 30 fps footage is exactly 30 fps. I think (but I'm not 100% sure) that exactly 30 fps (vs. 29.97) is not recognized by FCP. I wonder if you transcoded the footage to 29.97 if that would solve your problem?

Ron Dawson
Executive Producer/President
Dare Dreamer Media

Creating films that inspire and encourage the human spirit.

*** Dream Out Loud ***


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Cuauhtzin Gutierrez
Re: Audio sync drift problem with HVX200 P2 capture
on Aug 29, 2011 at 2:24:36 am

Just tried exporting the video as 29.97 in mpeg streamclip... no luck.

I found another thread on here that described my problem perfectly just like the OP. http://forums.creativecow.net/readpost/193/883011

I'm guessing the settings on my camera were a bit screwy. Seems like the video plays at 24fps while the audio is at 30fps. The audio can't catch up with the video which is why it keeps going out of sync even when I line it up manually. Not sure why it plays back fine on the camera but once imported it's off sync.

It's not perfect, but the work around I'm using now is leaving the audio alone (in a 29.97 timeline) and slowing the video down to 90%. It doesn't always look perfect but it's the only option I have (I think). Covering up a lot of the interview with b-roll is helping too.

Never shooting at 30P again. I've shot in 30PN before and it worked fine so that's what I'm sticking with from now on.


Thanks for the response!



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