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weird sync issue with blackmagic card...

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Chad Briggs
weird sync issue with blackmagic card...
on Apr 12, 2006 at 3:41:09 pm

I know this problem is a bit vauge, but it may have to do with our BM card and I was looking for some pointers, here it goes:
We have a 4:2:2 SD blackmagic card in our G5. Works great. We also have a betaSP UW-1800. Works great when you play back from a tape.
The problem becomes when you have the BM card and the deck hooked up at the same tape as a pass through. (meaning the BM card hooked up via component to the SPdeck, the SPdeck hooked up to the monitor via component). I get a weird "vertical sync" issue where it looks like vertically the screen has been offset (like you moved it down and it's repeating at the top, like the offset tool in photoshop). This is also werid, because it moves around after a random perid of time. Sometimes it will shift enough so the picture looks perfect, but then it will shift vertically again.
Any ideas why the deck is doing this to the BM card signal or what on the BM card signal is causing the deck to do this?
thanks
Chad


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Bob Zelin
Re: weird sync issue with blackmagic card...
on Apr 12, 2006 at 9:44:43 pm

Bet you don't have a black generator in your system, locking the Beta 1800 Ref Video Input with the Blackmagic Genlock input.

Bob Zelin




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Chad Briggs
Re: weird sync issue with blackmagic card...
on Apr 12, 2006 at 11:47:10 pm

so just to make sure i understand, your wanting me to connect the genlock in from the bm card directly to the ref in of the deck? If they are both "In" wouldn't that cancel out?
sorry for my video routing ignorance...
chad


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Kristian Lam
Re: weird sync issue with blackmagic card...
on Apr 13, 2006 at 1:22:18 am

Hi Chad,

Try sending the Y output of the DeckLink card into the REF IN of your deck, then take the loop out and send that back to the deck's Y-inputs. Remember to turn off the 75ohm switch when you do it.


regards

Kristian Lam
Blackmagic Design


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Bob Zelin
Re: weird sync issue with blackmagic card...
on Apr 13, 2006 at 12:44:44 pm

No offense here Kristian, but I am constantly amazed that Blackmagic continues to support the fantasy that professional video products do not need to be Genlocked. One of the nost attractive features of the yet to be released Blackmagic Multibridge Studio, is the built in black/tri level sync generator, which can feed multiple sources that lock to the Blackmagic product.

This gentlemen currently needs to purchase a color black generator to resolve his problems. These rediculous tricks of looping the Y signal will not help him as his system grows. A Horita BSG-50 is $289 in most mail order catalogs on line, and certainly even cheaper on eBay.

To be clear Chad, you take one output from your Black generator and send it into the Genlock input of your Blackmagic card, and take a second output of the black generator and send it into the Ref Video input of your UVW-1800.
If you are doing an insert video, you should also send black into the Video input of your UVW-1800, even though you are using the Y, R-B input (component input) of your 1800. The 1800 likes to see STABLE SYNC on it's reference and video input. When you make a black tape, so you can EDIT TO TAPE, this is called an insert edit, and you will need to record that black tape with color black being sent into the composite video input of your Beta 1800.

No offense to anyone, please -
Bob Zelin




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Chad Briggs
Re: weird sync issue with blackmagic card...
on Apr 13, 2006 at 8:57:33 pm

Bob-
Thanks for the detailed explanation on the blackburst generator setup, and that def sounds like the setup i need to get to. For now, just to get this project done, the looping trick Kristian suggested seems to be working so it will have to do. Ah, the joys of analog video :)
-Chad


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Bob Zelin
Re: weird sync issue with blackmagic card...
on Apr 13, 2006 at 9:52:28 pm

it's not just the joys of analog video, you MUST use a reference (sync) signal for SDI and HD-SDI as well. And when you use odd frame rates (like 23.98), you must use a Tri Level sync generator. Blackmagic will soon release the Multibridge Studio, which will offer Color Black Sync and Tri Level Sync outputs as part of the product.

Bob Zelin




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Kushal Shah
Re: weird sync issue with blackmagic card...
on Jun 17, 2006 at 9:20:50 am

HI Kristian


I am also facing similar Problem with PVW2800P
beta guy suggested i should switch off the VITC and that would help
my concern here is since we are useing component video output
taking Y out should be ok ????? we can put T connector and take it
in the middle of the patch????


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