Q: iMovie '11 audio sync issues since 9.01 patch

Anyone who had a Canon DV camcorder knows this problem. Audio and video are clocked using two clocks that are running at APPROXIMATELY the same correct rate. Over time A and V drift further and further out of sync. If you import the clip and use clips far down a long tape, they will not be in sync. Some NLEs eventually included a software fix that worked during import. So if you shot video with a Canon, you have a far more serious problem. (My bet, lots of folks with problems shot with Canon DV camcorders. That;s why I never bought one as it was a well know bug.) In theory you can detach audio and resync.

Anyone who is old enough to remember Premiere 4.2 knows this problem well. Here it makes no difference if the audio on tape is perfect. Long clips inherently go out of sync as they are exported. It wasn't until 4.6 that this was fixed.

The cause of all this is DV uses UNLOCKED audio. Nothing forces the sync between A and V.

Bottom-line, I suspect that this problem caused by DV's unlocked audio, Canon DV camcorders, iM09, iM11, and 9.0.1. If it's just the latter, Apple may find what they broke. But, they will never go back and fix any code related to DV.

If you shot a Canon camcorder, removing 9.0.1 will may help, but you have an inherent problem unless you re-apture in 10-min segments. For others, going back to 9.0.0 should help. But, you'll lose all the other fixes that were in 9.0.1. And, you may never be able to apply the fixes in 9.0.2, etc.

We know average viewer interst fails after about 7 minutes, so why on earth are people making 2 hour movies. Real movies are only slightly longer than 90 minutes.

My footage wasn't captured using a camcorder at all (Canon or otherwise). Also, my end "movie" ended up being 45 mins. But my source footage (imported VHS) was much longer than 2hrs. To preempt any "Well then whoever was doing the VHS shot for way to long..." business, the actual clips were already pretty short. Only the tapes were imported as single files.

I agree that unlocked audio could be a big part of the problem: The misalignment is squirrelly as I'll-get-out. Some spots are 10 seconds off (and not at the end of the clip), and other places are only 20ms off (that section had a little kid banging something; thank god for transients). I'm starting to understand why the B&H catalog has $1000 units that do nothing but clocking/sync.

Thanks Paul, I will check the Audio sync after importing analogue video footage via the Sony DV camcorder. But first I have to finalize my actual projects.

If I'm reading this correctly, you're saying that the sync is moving around, starts out OK, drifts out, drifts back, gets close, goes back out. Is that right? That would be really strange. I've never heard of that happening.

My EXACT problems, if I wasn't clear:

1. On import, long (>3 min.) clips get the out-of-sync problem. At the beginning of a clip, audio is fine, then progressively gets more out of sync as the clip goes on. The next clip from the same camera (ie, recording stopped, then started again) starts as in sync, then does the same thing. In other words, the problem hurts each clip individually based on that clip's length.

2. When a completed project is exported, it exhibits the exact same problem: audio starts in sync, and gradually worsens, til a 6-8 minute project is effectively ruined by the end. If I go into the project and detach the audio from EVERY SINGLE clip (missing just one clip ushers in a whole new set of problems), it somewhat mitigates the problem. However, doing so will cut off audio at transitions, rather than blending it as it would normally. This means I have to go through to each chunk of audio and lengthen it ever so slightly over the transition, otherwise people's voices just cut off mid-word at the end of clips. Needless to say, this process takes a very, very long time.

Calls to tech support produce zero results. I was hung up on more than once when I brought up this problem.

Hey there,

9.0.2 was just released and it fixes my sync problems, give it a try.

Wow, two months later, they fix it.

The only issue with this: If, in certain projects, you mitigated the original import problem by detaching audio and dragging it sideways to sync it up, those projects are now out of sync and will have to have their audio dragged back into normal position.

Hey Inky,

You can get back to normal easily. Just delete all of the detached audio files. Then select all of the video clips and raise their volume in the inspector.

This is what I get for not waiting one more day... I'll probably go "back" to '11; I love the "new" timeline. @Tom, yes the sync problems did fluctuate; I initially thought it was an audio buffer problem because the more I jumped around in the clip, the worse the sync problems seemed to be.

Can someone tell me how to align an audio file recorded on garageband while filming using camera with no ext mic. I have the external audio and the clip together in the project window, I used a clapper so syncing is no issue, but the clips are off by a few seconds. It seems like I should be able to click on the audio (or video) and drag them until they line up.

DUH, I just figured it out--you can drag the audio to precise position by clicking the area of the track that is ABOVE the video track.

Did the 9.0.2 update fix this issue for everyone? I have the update and just imported about 6 hours of old vhs footage and am still having the same audio sync issues as others were having on 9.0.1.

Anyone else out there still having problems?