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Audio/Video Sync question
Could a faulty Black Burst generator cause the audio to be 2 frames off on anything that is output to beta tape? Or could having to many BNC cables input into the Black Burst inputs throw something off. We currently have 3 cables hooked up and the other outputs are not out of sync so I doubt this is an answer.
Everything is locked up in the sequence but when it is output to beta the audio shifts forward 2 frames from the video. This is on the G4…FCP 4.5….Lacie 200 gig drives. I haven’t gotten to experiment yet plus we haven’t invested in a new black burst generator. I thought this would be a good place to start.
Any comments are appreciated.
Thanks
Lee
G5 Mac OS X
Dual 2.0 Ghz
FCP 4.5 HD
XServe Raid 1 TerabyteG4 Mac OS X
Dual 1.25 Ghz
FCP 4.5 HD
Lacie Drives 200 Gbs -
4 Replies
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Burst should have NO affect on A/V sync.
How are you monitoring FCP’s output for quaility and Sync?
How do you OUTPUT to Beta? What kind of D-to-A?
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Thax,
Thanks for the quick response. I’m not sure that I followed 2 of your 3 questions. 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. On 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 where it is looped through the monitor and to the beta deck.
I hope that answers your questions
Thanks Again
Lee
G5 Mac OS X
Dual 2.0 Ghz
FCP 4.5 HD
XServe Raid 1 TerabyteG4 Mac OS X
Dual 1.25 Ghz
FCP 4.5 HD
Lacie Drives 200 Gbs -
[Lee Burrows] “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. On 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 where it is looped through the monitor and to the beta deck.
I hope that answers your questions “
You didn’t mention the Black Magic card in your first post, so I didn’t know how you were monitoring or converting to analog. And I don’t know anything about Black Magic… hope someone reading does.
The audio “shift” must be happening during the Black Magic D-to-A conversion (if its OK in FCP).
The way you have your monitor set up (it goes thru the monitor and then to the tape deck is just fine (as is the “gender-changers” on the XLR’s) these short pathways would not affect any timing.The thing that must be noted is that the sync timing would be visible on the monitor as it is in the same signal path (and timing) as the deck.
You might re-post this question with
“Black Magic audio-sync problems” (or similar) as your Subject Name. -
Thanks for the advice Thax:) I’ll let you know what happens.
G5 Mac OS X
Dual 2.0 Ghz
FCP 4.5 HD
XServe Raid 1 TerabyteG4 Mac OS X
Dual 1.25 Ghz
FCP 4.5 HD
Lacie Drives 200 Gbs
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