Chroma key problem

Hi,

I have ATEM 1 M/E, i am trying to set up a chroma studio for live production. the background is green and i got a Sony Z5 camera going HDMI out. The background that i am trying to put is played out of a PC using HDMI too. Both and the ATEM running at 1080i50.

The problem i am having is that i have noise on the black level when i make the cut, little dots.

Please advise.

Thank you

Chroma key is delicate, and you have to really play with the settings to make it look correct.

With that said, I too sometimes see what looks like noise on the ATEM preview/program output, but when it's captured or sent out live, the final result doesn't show the noise, it's perfectly clean.

You can try to get some more light on your subject and less on the background. Also don't forget to backlite the subject.
The ATEM chroma keyer still needs some work in my opinion. Lots of times it gives you exactly what Serge describes, either the blacklevel of the chroma background is not right, or the dark parts of the subject are too noisy. It's quite hard to get those both right.

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Mike Squires

I had an old JVC mixer that worked just fine on the same setup.
Also, i have another setup with new and better lighting equipments and still get the same result with both switchers.

The JVC works perfect on both and the ATEM has the same problem on both. either with blue or green background i get the same result. the cut is a;most perfect yet there is some sort of hum or noise in the black and dark grey levels.

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Mathijs

The light is well oriented and the cut is fine but as u said the problem is in the dark parts of the subject.

Has anyone heard something from the Blackmagic people?? do they know the issue or is there a solution? or is it something i have to deal with?

i just bought the ATEM for the chroma Key, i have no use for it other than that

i just bought the ATEM for the chroma Key, i have no use for it other than that

Then I imagine it's a bit of a disappointment. I always say the ATEM is a great bang for the buck, but of course it has it's good points and some less good ones.
The chromakey is the less good thing. I know lighting conditions that work fine on other setups, give exactly this problem on the ATEM. When the blacklevel is set right for the image, the dark parts on the subject get very noisy. Lots of times it is usable when using key fly and to use a full body shot on some background, but when used without shrinking it down it is not very usable most of the time.
Also difficult to get the green halo totally gone without breaking up other parts of the image.
I just hope they will put some devtime into the chroma key on a future udate.
It is just frustrating when you can almost get it right, but the sweet spot seems to be overlapped both ways.