-
AUDIO/VIDEO SYNC PROBLEMS
Hello all! This is my very first post to this forum–don’t be too harsh!
First, a little background: I’ve had a broadcast journalism degree for 15 years, and the first 14 of those years were spent in public radio. But recently, the communications department of the university where I work found itself stuck between a rock and a hard place: The need for somebody to produce VNRs about university research & extension programs… but without the necessary funds to hire somebody outright to do that. So I volunteered to transfer out of my “radio digs” and try a bit of video production.
Last year, I had a video workstation set up in my old office, on the other side of campus. A couple of weeks ago, that same system (details below) was dismantled and installed in my new office. Same Mac G5, same software (FCP HD), but there are a couple of differences…
1) I now have two widescreen monitors, instead of one
2) There’s a new video card in the system: an AJA Kona LS card. Previously, I was just using FireWire for import/export.
Since then, I’ve suffered recurring loss of sync on all my FCP timelines. This includes both old material (projects that were loaded within the past year, in my old office) and new video captured in just the past day or two. Sometimes, the video seems to be lagging several frames behind the audio; other times, it’s the opposite.
I’ll open up a project… fire up the timeline… hit the spacebar, and everythings out of whack. Tap the spacebar to stop playback, immediately tap the spacebar again… and now everything’s in sync. Step away from the system for a minute or two, come back, hit the spacebar… now we’re out of sync again. The machine truly seems to be deciding at random whether or not it’s going to play back the timeline in sync!
A couple of days ago, I opened up a timeline that I started just the previous day. I exported @ 60 seconds of the video to a self-contained QT movie. When I play the movie… video and audio is in perfect sync!
MY SYSTEM
Dual 2GHz PowerPC G5
3 GB DDR SDRAM
OS 10.4.6
ATTO ul4d SCSI card
2 Medea RTR drives stripped as a single RAID for local storageSTILL TO ADD:
Distribution amps, both audio and video
Right now, only component and SDI… composite will be available once the amps are installed.
That’s where we’re at right now. Thanks for your help! 🙂
-
3 Replies
-
Sounds like your playback offset is still set to 4, which is default for FCP. That should be 0 for use with any Kona product.
Walter Biscardi, Jr.
https://www.biscardicreative.comDirector, “The Rough Cut”
https://www.theroughcutmovie.comNow Posting “Good Eats” in HD for the Food Network
“I reject your reality and substitute my own!” – Adam Savage, Mythbusters
-
Thanks for the info, Walter. The problem has disappeared for the time being, but there were three things we did over here:
1) Changed “Frame Offset” from 4 to 0 in “System Settings”
2) Reduced “Real-time Audio Mixing” from 8 to 4 in “User Preferences”
3) Updated Quicktime… currently Version 7.1.0, Player Version 7.1 (7.1)
We tinkered with both of the first two settings above (our engineer had heard that having the audio mixing setting too high could cause problems), and even after leaving Frame Offset at 4 and Audio Mixing at 8–returning them back to their original settings–playback is still greatly improved.
So… now wondering if maybe the QT upgrade was just what the doctor ordered…?
In any case, I’ll set Frame Offset to zero again, per your recommendations. Can’t argue with anyone who works with one of my favorite shows, “Good Eats.” :p
Thanks!
-
if you have any picture/audio sent out thru firewire you should know there is around half of sec delay compared to what you see on screen.
Reply to this Discussion! Login or Sign Up