Audio Sync Slippage

Hey all,
Is anyone else getting Pro Res files out of the camera - long takes - where the audio slips sync by the end? I'm looking at the files completely independently of FCP or Avid. Just as a quicktime. And the sync always slips. I always record audio separately so it's not a horrible thing - but it would be nice to solve this and get the workflow smooth. Thanks, H

I know this sounds like a strange question, but how are you looking at the Quicktime movie? On a Mac or PC? With QT 7 or QT 10? Or are you using fast preview in the finder?

The reason I ask is that sometime, if you use a preview function of the Finder as opposed to opening the file in QT, you can get strange sync results. Have you tried just watching the back half of the film and it's still out of sync or is it drifting while watching the whole film and it's drifting?

If you're on a PC, I defer to someone more knowledgable.

Also could be that your timeline where you see it or project settings are wrong in fps or sample rate.

Also could be that your timeline where you see it or project settings are wrong in fps or sample rate.

Yeah, this. Make sure something isn't 23.98 vs 24fps or something like that...

Bobo, make sure your SSD is freshly formatted before you start recording.

I had dropped frames in both ProRes and RAW recordings - which led to AV sync issues! - until I started re-formatting the SSD each time before using it in BMCC.

Hey guys! Thanks for replying. I have an interesting one for you though I think.
As I said, the audio sync slips *in the quicktime itself* without it ever being put into a timeline or anything.
The frame rate is 23.98, I'm shooting in ProRes.

I reformatted the drive as you suggested. ( I haven't been having any dropped frames)
Then ran it again for a little over an hour. I sync clapped at the beginning and then again 1:06 later.
The ProRes file STILL ends OUT OF SYNC.

I threw it in a timeline in FCP just to double check - frame rates of course matching.
The first clap is in sync. And at the second clap - the audio is exactly 19 seconds EARLY.

When I record to the 744 and have a separately recorded audio file, everything lines up perfectly.
So what's going on inside the BMCC?

Running a Mac. Tried it in both QT7 and QT10.

Crazy right? Is Blackmagic bending reality?
Thanks for any ideas.
Bobo

What SSD are you using?

The m4 Crucial 512 that was on the recommended list when I got the camera...

Try shooting a test at 25fps and see if you can reproduce the same issue.