Sync drifts in Final Cut Pro with Xsan

huntson · Could work for Apple Joined: 27 Mar 2012 Posts: 43

I am using FInal Cut Pro with Xsan and the sync is constantly drifitng between audio and video. I have read elsewhere that people have had this issue but I haven't found any of my solutions. My Xsan seems to be all setup correctly and I am only working with DV footage. Any ideas?

huntson · Could work for Apple Joined: 27 Mar 2012 Posts: 43

MDC is on 10.7.2 while clients are on 10.6.8. I now seem to think that it is the Kona LHe card in one of my clients as it doesn't happen with another computer and the LHe has tons (relative to non) of complaints about out of sync audio and video.

abstractrude · Xsan Master Joined: 13 Mar 2008 Posts: 881

are you having the issue on local storage as well? This issue is usually caused by bad sync or reference. do you have timecode coming with your source material? tell us more about your workflow.

huntson · Could work for Apple Joined: 27 Mar 2012 Posts: 43

local storage is all good to go. it looks like it was a bad fibre card - new one has rock solid sync. do i really need genlock going to a video card if i am just outputting to a monitor?

huntson · Could work for Apple Joined: 27 Mar 2012 Posts: 43

turns out I was wrong. On occasion when playing back it still is a bit out of sync. If I stop and hit play again - it works just fine. Any ideas? Again, local storage is good to go.

JSamuel · Xsan Master Joined: 05 Jan 2011 Posts: 177

Look at the FC switch; MDL switch and storage unit logs as you're trying to reproduce the error... MDC/Client logs too may help.

keithkoby · Xsan Master Joined: 04 Apr 2006 Posts: 140

I don't think it's fiber, switch, card or SFP. Either you get bandwidth or you get dropped frames. We've seen a situation like this when using a 10 bit codec at hd res (prores 1080i) on a macpro 1,1 with an LHE. The thing about FCP is that it decodes video on the CPU and then hands it over to the aja. The computer couldn't keep up with the decode... You could test the situation by switching video playback from 10 bit to 8 bit in the a/v settings in FCP. 8bit is in sync, 10 bit out.

It sounds similar to that situation so I might start by checking the easy setup in FCP. Make sure the editor hasn't made a custom set up using the 10 bit aja video out for an 8 bit codec (dv).

keithkoby · Xsan Master Joined: 04 Apr 2006 Posts: 140

One more thing...

I forgot to mention you should control for the aja/FCP in some way. Maybe by opening the file in qt 7 player. Open the info window (cmd-I) and see if the playback frame rate matches the framerate and that playback is smooth. Sync shouldn't drift there...

Then control for FCP by opening the file in aja tv. See if audio drifts there.

keithkoby · Xsan Master Joined: 04 Apr 2006 Posts: 140

Well - this is funny. Exact same a/v drift situation just happened on a new mac pro and we replaced the LHe with a new LHi and the problem went away. Not sure how old the LHe was, but you might want to swap cards if it is old.