Color Banding through HDMI out

B

Billygoat

Active member
I'm wanting to know if there's a difference between the output of the HDMI out and the SDI out, in terms of compression or signal. Looking at my 50" Panasonic plasma studio monitor with HDMI input from the AF100, color gradients on soft focus backgrounds are very noticeably color banded, and you can watch them migrate and radiate in and out as you change exposure. I do not currently have the ability to check the same output via SDI. So I am wondering if the HDMI is the AVC compressed output, or if it is the same as what I would be seeing (and recording with a Nano Flash) through the SDI. Anyone know?
 
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I would think the color banding is due to the 8-bit output of both the HDMI or SDI, not the compressor. When comparing the footage out of my AF100 to my 7D, I notice the banding when there is absolutely no noise in the image, whereas the 7D has a little noise in it, which helps mask the banding. I too noticed this most on out of focus backgrounds. What I am trying to do is push a little noise back into the camera so it's just there to break up those band edges.
 
HDMI an HDSDI are the same quality. A lot of the banding I've see via HDMI either was a poor quality monitor or a poor connection (cheap or bad cables and adapters).
 
Brian@202020 said:
HDMI an HDSDI are the same quality. A lot of the banding I've see via HDMI either was a poor quality monitor or a poor connection (cheap or bad cables and adapters).
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Well the monitor is a Panasonic TH-509UK "Pro Plasma". Panny HDMI card. I'm a little skeptical that the HDMI could be the source, but I will check it. I really wish it were something other than the camera. I did notice the same color banding in the sky of "The Verse", but unsure the source. I'd like to see this NOT being the camera.
 
Billygoat said:
Well the monitor is a Panasonic TH-509UK "Pro Plasma". Panny HDMI card. I'm a little skeptical that the HDMI could be the source, but I will check it. I really wish it were something other than the camera. I did notice the same color banding in the sky of "The Verse", but unsure the source. I'd like to see this NOT being the camera.
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If you saw banding in the sky on "A Verse…" I can assure you that it's a by-product of the Vimeo compression. We saw no such banding in the color suite on our corrected clips.
 
Stephen Mick said:
If you saw banding in the sky on "A Verse…" I can assure you that it's a by-product of the Vimeo compression. We saw no such banding in the color suite on our corrected clips.
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Yes, that was my assumption when I first saw it. But I'm seeing it right out of the camera now (not as prevalent as that profile shootout shot in the sky of "The Verse"), but enough to make me want to find a culprit other than compression or shortcomings of 8-bit recording.
 
trust me... working in the post production FX industry for 20 years, 8bit needs some grain to mask banding. There is simply no way around it. It's not a big deal if you now how to work around the limitations.
 
That's my observation as well. I set my AF100 to be so clean that the banding shows. Back down a little on the settings and those edges are more dithered basically because of the noise, so they look better. Got out my 7D to compare the images and sure enough, I can get them VERY similar. (minus the color differences)
 
I worked at Quantel many years ago, retouching on the Graphic Paintbox and Printbox.

8-bit realtime 5k x 4k images, and even on those beautiful beasts, a bit of noIse on gradients was your friend - a nice bit of dithering to kill the quantizing.
 
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The banding I saw on my plasma is NOT in the footage. I'm not sure where in the chain it is being introduced, but I looked at some footage in After Effects, blew up the frame, and it is NOT banded. So great news there. Just not sure where its coming from in the output...maybe the hdmi card on the monitor.
 
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