Luminance Keyer shifting video horizontally

[settlement]

Hello,

When I activate the luminance keyer on a live input, the video shifts a tiny bit to the left. When I de-activate it, the video shifts back to the right again. Would this be something fixed by adjusting the center frequency?

This does not seem to happen if I take a channel digital, or grab a framestore of it. Only if I activate the luminance keyer. It is very noticable just by going from levels 000 to 001 in the keyer and back.

Toaster 4000 / Flyer / A4000T / T/F 4.3.

Thanks,
Tim J.

[tonyvdb]

Hi Tim,

One question, do you have the input video going through a TBC before entering the Toaster?

[settlement]

Hi Tim,

One question, do you have the input video going through a TBC before entering the Toaster?

tonyvdb,

Yes, essentially. All video sources are synchronized to the same black-burst generator. The source I am trying to luminance-key is an Elmo document camera. Lemme go see if it happens on the other sources...

DPS PAR: Yes
Panasonic AG-7650: Yes

Thanks,
Tim J.

[tonyvdb]

Its a good rule of thumb to leave input one as simply a signal coming from the blackburst generator sent through the TBC and that way you have a nice solid singnal to lock to on the toaster. The Toaster uses input one to keep all the other inputs in sync so using input 2 through 4 for your incoming video is a good idea. Remember that you must have at least one TBC on input one (more if you use the other inputs as well) for the toaster to function even if your using the Flyer. The Blackburst generator is not a TBC and will not correctly sync all inputs.

[settlement]

Its a good rule of thumb to leave input one as simply a signal coming from the blackburst generator sent through the TBC and that way you have a nice solid singnal to lock to on the toaster. The Toaster uses input one to keep all the other inputs in sync so using input 2 through 4 for your incoming video is a good idea. Remember that you must have at least one TBC on input one (more if you use the other inputs as well) for the toaster to function even if your using the Flyer. The Blackburst generator is not a TBC and will not correctly sync all inputs.

Hi,

Isn't it redundant to put a blackburst signal through a TBC? With all sources sync'ed to the blackburst, any of them should work on input one, right?

Are you able to duplicate this on your setup? On the Switcher panel, with (1) the Keyer set to "off" and "000", if you (2) set Main to a live input (let's say Input 2), then (3) set the Keyer to a different live input (let's say Input 3), then (4) activate the Keyer on either white or black, and then (5) toggle between "000" and "001", do you notice the Keyer-overlaid video (from Input 3) shifts a little to the right?

I have tried adjusting the horizonal sync on my sources to get them in line, but no new setting made any difference. I realized, though, after giving up for the night, that this isn't really even a problem, since how often would I have to go from 000 to any other value in the keyer? I can just start at 001 and go up to 250, and most of the time, I would only need 001-065 anyway. But we'll see.

Luckily, this problem only seems to occur when keying a live source over another live source. Keying a live source over a Flyer clip or a Framestore does not exhibit this behavior. Nor does keying a Flyer clip or Framestore over another Flyer clip or Framestore. Or CG. Or any of that good stuff :D

Thanks,
Tim J.

[tonyvdb]

A blackburst gen is only a stable black video source that aolws the toaster to lock to but a TBC actualy strips the videos time code and rewrites it so if there are any inconsistency's in the video your Toaster will lose sync.
I would say thats your problem as you must have a TBC on at least input one for the toaster to function properly.

[settlement]

A blackburst gen is only a stable black video source that aolws the toaster to lock to but a TBC actualy strips the videos time code and rewrites it so if there are any inconsistency's in the video your Toaster will lose sync.
I would say thats your problem as you must have a TBC on at least input one for the toaster to function properly.

AFAIK, a TBC is only necessary when you're using tape. You could have four live cameras hooked up to the Toaster with no TBCs, so long as the cameras are all sync'ed together. Maybe I'm wrong though...

Thanks,
Tim J.

[tonyvdb]

AFAIK, a TBC is only necessary when you're using tape. You could have four live cameras hooked up to the Toaster with no TBCs, so long as the cameras are all sync'ed together. Maybe I'm wrong though...

Thanks,
Tim J.
A Blackburst generator dose not sync anything all it is is a perfectly black video signal nothing else.
Your partially correct that a video tape needs a TBC but only if it is an analogue signal that is coming from the video out not firewire such as a VHS, 8mm, etc particularly if its multiple clips but also any analogue video such as from a camera also requires one. it will work but you can not do any transitions between inputs unless they pass through at least two TBCs that have been synced together.
I have 4 TBCs on my Flyer and do not have the problem you describe.

[settlement]

A Blackburst generator dose not sync anything all it is is a perfectly black video signal nothing else.
Your partially correct that a video tape needs a TBC but only if it is an analogue signal that is coming from the video out not firewire such as a VHS, 8mm, etc particularly if its multiple clips but also any analogue video such as from a camera also requires one. it will work but you can not do any transitions between inputs unless they pass through at least two TBCs that have been synced together.
I have 4 TBCs on my Flyer and do not have the problem you describe.

Well, that's kinda my point. The camera has a genlock input and is sync'ed to the same source as the SVHS deck and the DPS PAR. All of my sources are sync'ed. The deck has a built-in TBC, the PAR has a genlock input (so it's sync'ed), and the camera has a genlock input (so it's sync'ed). I can do transitions till the cows come home. I can overlay graphics and do wipes just fine. The only problem is when I (a) activate the Luminance Keyer between two live sources, or, as I recently discovered, (b) activate a ChromaFX on a live source.

I will try running two sources through two TBCs (sync'ed together) and see if the problem still occurs.

Thanks,
Tim J.