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Black Magic audio-sync problems-2 edit suites – 2 issues
1st suite
Could a faulty Black Burst generator cause the audio to be 2 frames off on anything that is output to beta tape or could it be the Blackmagic video card? It is probably not the card as it has had 2 different Blackmagic cards(Decklink SP card and the Decklink Extreme) in the same suite on a G4 and now a G5 and it is still has the identical problem. Sometimes its in sync and other times it isn’t. I haven’t been able to narrow the path to the solution and thought that this would be a good place to start. I’m pulling my hair out…help:)Here is the route we go from the FCP sequence where the audio and video is locked up out to analog beta.
Everything is locked up in the sequence but when it is output to beta the audio shifts forward 2 frames from the video.We laying off to analog Beta tapes and from there we notice the sync issue when playing back interviews. I have also run several tests involving bars and tone and a film clicker(directors take card/board). These tests confirm that the A/V is 2 frames off.
We output from FCP to the Blackmagic cable. Audio then goes from the BM cable to another XLR cable to the Mixer then from the mixer out to beta deck. One note – We had to attach gender switching connectors to the XLR ends of the BlackMagic because they were not configured right.
The video goes from the BM cable to an NTSC monitor(Y/B-Y/R-Y) where it is looped through the monitor and to the beta deck.
We upgraded the suite from G4/FCP4.5/Blackmagic decklink SP to G5/FCP 5.0/Blackmagic decklink extreme and the problem has not gone anywhere…ocassionally appearing:(…ocassionally not:)
2nd Suite..2nd problem
This suite has the original G4/FCP4.5/Blackmagic decklink SP transfered to it from the 1st suite. Now before we moved the G4/FCP4.5/Blackmagic decklink SP to the 2nd suite the video card that fed the NTSC monitor the video desktop would flicker between black and the desktop and cause any video and audio played whether on quicktime or through FCP to skip or flicker simultaneously trveling through the Sony NTSC monitor.
Upon transfering the G4/FCP4.5/Blackmagic decklink SP to the 2nd suite with the same set up the problem has progressively gotten worse over time to now it does it 90% of the time thus making it practically impossible to dump anything out to tape. Now we have tested a scenario where we saved a QT movie out of this system to a CD and played it on another computer and it plays fine. So it saves it fine as a QT file even though the G4 plays it bad. My guess is that the video card might be loose in the machine but I have not had time as of yet to try and tighten it. Luckily we don’t do much work in that suite thus avoiding the problem.
The other thing that is worrying me a little is that suite 1 which we have owned for 6 months now has over the past month had a couple of episodes for just of moment or 2 of that dreaded flickering. I pray it doesn’t doesn’t begin in there.
Could the computer heating up affect the cards into doing that and eventually damage a card where it is irreversible and does nothing but go downhill? Neither room is hot nor cool. They are generally room temperature maybe a little warmer because of the equipment. We have other computers around the office in this environment that seem to function fine.
Any help is appreciated:)
Lee
G5 Mac OS X
Dual 2.0 GHz
FCP 4.5 HD
XServe Raid 1 TerabyteG5 Mac OS X
Dual 2.3 GHz
FCP 5.02 Studio
G-Tech G Raid 500 GBs
2 – Lacie Drives 200 GBs -
3 Replies
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Hi,
Happy new year to you all.welcome to outsync world of decklink card/drivers.
please refer to these posts
[HELP] Audio out of sync!!! ..it’s QUICKER than video! by Master of Desaster on Nov 22, 2005 at 2:12:37 pm
and mine on 29 sept.
So far no solution from decklink. My only solution is just before you are about to “master to tape” reboot and wothout doing any thing else “master”.
sorry i can not help any further.
good lucksameer shrivastva
bye -
We had a similar problem with output from a dual 2GHz G5 machine with audio one frame out most of the time. This was running FCP 4.5 but the problem went away after driver upgrades. We have since upgraded to FCP 5 and are running two similar machines with FCP 5.03 and are having no problems.
A work around for us when we were having the problem was to offset the audio by one frame during output (i.e. move the audio one frame on the timeline). Obviously this only works with some material and you can’t do it when inserting to a previously mastered tape.
I suggest that you check that you are running the latest OSX and drivers compatible with your version of FCP. You may find your problems disappear.
PS. If you think the world of sync is problematic with a Decklink card, you should try a Cinewave. We gave up on ours.
Trevor Kinsey,
Technical Producer,
CVP Film and Television,
Melbourne,
Australia -
Got a similar problem but not quite. Everything stays in sync or is out of sync until you stop. If I play a section of my edit the sound is 2 frames early and stays that way until I stop and play again. Then it might be early or it might be in sync.
So far all playouts have been in sync but I don’t know if this is just luck.
I don’t know if this is a card fault or FCP? It is reasonable to expect correct A/V sync isn’t it? Has anyone tried Kona cards?
I am running:
Power PC G5 dual 2.7GHz
3GB RAM
FCP 5.0.4
Quicktime 7.0.4
OSX 10.4.5
Blackmagic Deck Link 5.4.2 (card supplied with multibridge SD)
3x500GB G-RAID FW 800
External B&B ref
DVCPRO50 PAL codecSven
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