UVW-1800 analog component video output low into Decklink Extreme

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Level 1

85 points

UVW-1800 analog component video output low into Decklink Extreme

I have come to realize that my UVW-1800 is feeding into my Decklink Extreme card at 75% of the level it should (based on NTSC bars). I can raise the input level of the Decklink. But I wonder if the ultimate problem is increased noise using this fix. I am about to test the composite output level. I do not have a regular WFM moni so I can't see the level until after I get it in.

Thanks, Chris.

Mac G5 dual core 2 Ghz 2gig ram, Mac OS X (10.4.11), Decklink Extreme PCIe card, G-RAID 1/2T drive

Posted on Jun 11, 2009 5:32 PM

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Answer 1

Chris Howe Author

Level 1

85 points

Jun 12, 2009 8:02 AM in response to Chris Howe

Composite is the same.

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Answer 2

Jun 12, 2009 8:16 AM in response to Chris Howe

A shot in the dark, but could this be a termination issue. Haven't worked with the decklink so not sure if termination is an issue and if it's handled with a control panel or a physical switch.

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Answer 3

Jun 12, 2009 9:48 AM in response to Michael Grenadier

the only way you'll know for sure is to push the output from your 1800 through a good NTSC scope. There is nothing in the machine itself that will change the output of the integrated TBC, I have one. If you have the UVR-60 TBC remote unit hooked up you must have a scope since you can overshoot or undershoot easily.

It would be really weird for the device you're feeding to have a non-standard termination circuit.

bogiesan

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Answer 4

Chris Howe Author

Level 1

85 points

Jun 12, 2009 9:59 AM in response to David Bogie Chq-1

Thanks, problem seems to have to with quality of cable connections, because having done very little, the composite white level has jumped from 72 to 90 units viewed on the FCP scope. I understand that a real scope is best (I have to buy one), but it's becoming apparent that that increase I've achieved so far was 100% happening in the cabling between the deck and the decklink.

I know this because at one point I viewed the cmpste out direct to the NTSC monitor and it appeared brighter in an a/b test against the FCP log and capture loop through. Then something happened (cable issue) and they both looked the same, and brighter.

I need to test some other tapes to see why 90 is my max now. Much better than 72. And yes, I feel a little sloppy at this point!

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Answer 5

Jim Cookman

Level 7

23,447 points

Jun 12, 2009 10:55 AM in response to Chris Howe

How long are the cable throws? You might also want a distribution amp or three

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Answer 6

Jun 12, 2009 2:57 PM in response to Jim Cookman

Jim Cookman wrote:
How long are the cable throws? You might also want a distribution amp or three

A 20% drop in the voltage of the composite signal would show up after fifty miles of coax!

bogiesan

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Answer 7

Chris Howe Author

Level 1

85 points

Jun 12, 2009 5:10 PM in response to David Bogie Chq-1

The cables are relatively short. 8 to 10ft. each. I've determined it is not likely the deck, unless it's now putting out a consistent 90% white. I don't know yet. I believe the orig composite/Y cable (usually setup as component Y) was causing an intermittent signal drop. I am swapping it out for good.

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Answer 8

Chris Howe Author

Level 1

85 points

Jun 15, 2009 9:34 AM in response to Chris Howe

I came back to it over the weekend and the video level in is spot-on a 100 IRE. It's strange the way it's been a bit uncertain, but now OK. However, the chroma gain is now just slightly above normal. and this is, again, unaccountable. But if it stops wavering around, I can live with this as I can always crank the chroma back down.

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Answer 9

Jun 15, 2009 9:45 AM in response to Chris Howe

You're saying you do not have the TBC remote controls for your 1800?

bogiesan

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Answer 10

Chris Howe Author

Level 1

85 points

Jun 15, 2009 9:52 AM in response to David Bogie Chq-1

Correct. No TBC remote and no waveform/vector. I always worked worked under the assumption I would take in the unity input and do the best I could with it. But when the video input started to drop noticeably, that was cause for concern. That was apparently fixed with a new cable. The chroma being high now is an unexpected surprise, but maybe I can deal with it with out investing in a number of new accessories.

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Answer 11

Jun 15, 2009 9:59 AM in response to Chris Howe

The TBC remote is easily cobbled together with the pin-out diagram from the 1800's manual. One trip to Radio Shack and about four hours of soldering and you'll have a priceless tool.

also can be acquired from broadcast liquidators.

bogiesan

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Answer 12

Chris Howe Author

Level 1

85 points

Jun 15, 2009 10:02 AM in response to David Bogie Chq-1

Thanks for your time.

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Answer 13

Jun 15, 2009 10:57 AM in response to Chris Howe

Chris-

You might also look on eBay for a TBC remote. Even using the scopes in the Final Cut capture window will be OK. Analog video is subject to huge variations in levels and chroma. Getting them close to proper at the machine will give you a much more pleasing result than adjusting them after the fact in the digital domain.

The usual order of adjustment for analog machines is to first set the black level, then the white. If you adjust the white much it will affect the blacks, so go back and reset those. Which will affect the whites. so go back to THOSE. Usually about 3 tweaks on each will get both to the proper levels. Then set the chroma amount, and hue (if you are using the composite signal).

Finally on the %75 percent issue. It turns out that in analog video if you add the R,G,and B signals you only get 75%. So if you have full field bars that may be correct. You need SMPTE bars, which have a 100% white box at the bottom of the frame, to correctly set your video level.

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