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AVC Intra-100 footage VERY noisey...

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Simon Roughan
AVC Intra-100 footage VERY noisey...
on Jun 23, 2015 at 3:53:05 pm

Hello Everyone,
I have some green screen footage shot on a Panny AG-HPX301E, with AVC Intra-100.
The results are so noisey and blocky, it makes me wonder what I did wrong. We had a HD control monitor SDI out from camera, and everything looked fine there. When I loaded the footage into Premiere Pro, it looks terrible, especially in the dark areas.



This of course makes the keying very difficult, and the jacket looks like its swarming with ants.
Can anyone explain what went wrong?
Camera had no gain, filter 1, f5.6, no shutter speed.
Like I said, what I saw through the control monitor has no relation to what I have in Premiere Pro.

Thanks in advance
Simon

You know I'm born to lose, and gambling is for fools, but that's the way I like it, baby. I don't want to live forever!


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Tom Matthies
Re: AVC Intra-100 footage VERY noisey...
on Jun 23, 2015 at 4:05:19 pm

It's difficult to tell from your screen grab, but the picture looks very under exposed to me. That will make for lots of noise, especially in the blacks where you will have few bits (less range) trying to reproduce the details. What did you use as a reference when setting the exposure. I notice that they guy is wearing a white shirt. Was the exposure set off of the peak white of the scene?

Not my monkeys. Not my circus.


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Simon Roughan
Re: AVC Intra-100 footage VERY noisey...
on Jun 23, 2015 at 6:34:18 pm

Thanks for the reply.
I made a white balance with the iris on auto from a white card in front of his face, with a result of 2.6
But through the control monitor, it was way too bright. I closed it to 5.6, and it looked much better.
But like I said above, what I could see in my control monitor and what I have in the computer are 2 different things, unfortunately. The control monitor was also recently calibrated.

Simon.

You know I'm born to lose, and gambling is for fools, but that's the way I like it, baby. I don't want to live forever!


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Tom Matthies
Re: AVC Intra-100 footage VERY noisey...
on Jun 23, 2015 at 8:54:36 pm

That camera has a built-in waveform and vector display available. Use those rather than relying on a monitor for video correct levels. Also with high contrast situations (like the white shirt) make sure that your dynamic contrast compression is turned on. It will help prevent blowing out the highlights.

Not my monkeys. Not my circus.


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Sam Lee
Re: AVC Intra-100 footage VERY noisey...
on Jun 26, 2015 at 12:55:03 am

I also see the noise in the green screen area as well. I have similar problems with higher end 2/3" Panasonic cam when the scene doesn't have enough lux. I mean you really have to blast the scene with lots of light and the noise diminishes until you can shoot at f/8-11 at -6 dB gain. But it won't go away 100%.


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Simon Roughan
Re: AVC Intra-100 footage VERY noisey...
on Jun 26, 2015 at 7:58:20 am

Thanks for the reply.
Do you have any idea why the SDI out signal and the P2 card are so different?
Simon

You know I'm born to lose, and gambling is for fools, but that's the way I like it, baby. I don't want to live forever!


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Sam Lee
Re: AVC Intra-100 footage VERY noisey...
on Jun 26, 2015 at 2:22:55 pm
Last Edited By Sam Lee on Jun 26, 2015 at 2:38:34 pm

My theory between the uncompressed HD-SDI and P2 card is the codec it uses. Even though AVC-I 100 is mildly compressed, there's still compression. AVC Ultra 200 (found on newer 2013-present models) may be closer to uncompressed. You may want to try the HD-SDI signal to a uncompressed Mac/PC capture card to compare. Typically the easiest workaround for me is to blast the scene with near sunlight brightness (including green screen) and the black noise diminishes dramatically.

The noise issue has been found on earlier Panasonic 2/3" cams, including their popular SDX-900 DVCPRO 50 ten years ago. You only see it surface when color grading is applied. There the grains are magnified and is discernible. Overall it's an excellent low-light camera during its SD days. I was able to use up to 9 dB and it's virtually noise free. That 9 dB of gain is similar to 3 dB in today's 2/3" HPX3100-PX5000 models. I found anything beyond 3 dB with today's 2/3" cams are way too grainy. The only way to tackle this is to brighten the scene.


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