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Luminance Shift with 10bit RGB

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Matt Silverman
Luminance Shift with 10bit RGB
on Jan 30, 2007 at 10:16:16 pm

I am working in AE comping greenscreen plates shot with a sony f950 directly into FCP using the a Kona with the Kona 10bit 4:4:4 codec. When I switch AE to 16bit the image gets lifted. I wrote to support about this but never heard back. Is there a newer software codec to fix this? I typically like to do most of my work 8bit then switch to 16bit for rendering, but this codec is preventing me from doing so since CC's look much different in 16bit.

-Matt


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weevie833
Re: Luminance Shift with 10bit RGB
on Jan 31, 2007 at 3:48:36 pm

Are you working in regular HDcam or HDCam SR? If you working in regular HDCam, then working in 444 RGB is way overkill. HDCam is not a 444 format. It's still 422 Uncompressed 10-bit, like D-1, though the frame size and number of scan lines is different. Outside of this knowledge, I can't say that what you are trying to do is necessarily wrong. It's just that your monitor is probably not a 444 RGB monitor, and your footage is being 'converted' to 444 in the capture process. So maybe it's the monitor??? Just guessing here. Try doing it with the 10-bit UC 1080 23.98 Easy Setup [or whatever the native acquisition frame is]. steve covello double wide post


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gary adcock
Re: Luminance Shift with 10bit RGB
on Jan 31, 2007 at 4:17:37 pm

[weevie833] "HDCam is not a 444 format. It's still 422 Uncompressed 10-bit,"

Weevie

HDCam is 3:1:1 not 4:2:2

HDCAM SR records to tape at 4:2:2

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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weevie833
Re: Luminance Shift with 10bit RGB
on Jan 31, 2007 at 8:49:28 pm

Hmm. Take a lookie [HDCam]: http://www.maxellcanada.com/pdfs/pi/hdcam_wp.htm Looks like 422 to me. Here's HDCam SR -- looks 444 here: http://www.videocraft.com.au/page/hdcam_sr.html Where are you getting your info? steve


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gary adcock
Re: Luminance Shift with 10bit RGB
on Jan 31, 2007 at 9:11:20 pm


what the tape say it can do and what the camera and deck can do are 2 different things, and how the data is recorded to tape is another.

However that HDCAM CAMERA master is 3:1:1 @ 8bit.

and the SR series decks can record at 4:2:2 or 4:4:4.



gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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weevie833
Re: Luminance Shift with 10bit RGB
on Feb 1, 2007 at 2:05:44 am

I stand corrected. I looked up your info and it had more truthiness than the links I found.

Thanks Gary. I will now stop lying to my clients. :)

Steve


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Matt Silverman
Re: Luminance Shift with 10bit RGB
on Feb 1, 2007 at 2:01:17 am

4:4:4 is not overkill... The whole show is greenscreen with virtual environments. This was shot with the Sony F950 camera which is the SR camera. We had an SR deck as a backup, but to avoid the SR compression we went dual link out of the camera directly into FCP with Kona. It worked flawlessly except for this luminance bug.

For the record, your specs are really inaccurate. I suggest finding the specs chart from Miranda.
HD-CAM is far from uncompressed... 7:1 compression, 8bit, 3:1:1 colorspace. It's dead technology.
D1 is (was) not a 10bit format... it is 8bit uncompressed 4:2:2. Some folks still like to use it for effects shots. I prefer the larger color space in Digibeta (10bit 4:2:2 2.3:1 variable compression which is lossless a lot of the time).
All computer monitors are 4:4:4RGB. I see this shift on computer monitors and out 4:2:2 HD broadcast monitors.


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gary adcock
Re: Luminance Shift with 10bit RGB
on Feb 1, 2007 at 4:30:52 am

[Matt Silverman] "4:4:4 is not overkill... The whole show is greenscreen with virtual environments."

Agreed Matt --
this is the optimum usage of a 4:4:4 RGB master, it is what the format was created for.


Back to your original very first post-
it is my understanding that the 16bit version of the codec that AE uses is not optimized for the Mac based version of QT but for a Windows file based ( DPX or Targa) workflow.

Have you tried the 10bit Kona RGB or RGB Log versions of the Codec to bypass the native QT version of 10bit?


gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows


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Matt Silverman
Re: Luminance Shift with 10bit RGB
on Feb 1, 2007 at 8:07:32 am

I'm using the Kona codec, since the QT version is only for 4:2:2.


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weevie833
Re: Luminance Shift with 10bit RGB
on Feb 1, 2007 at 4:23:25 pm

You are correct on all counts. I was thinking F900, not F950. Also, since Sony does not give up its native codec to Apple, the logical capture mode for HDCam [assuming shot with F900] would've been 10-bit [or 8-bit] Uncompressed 422, which is a transcode of sorts. My point, of course, that for regular HDCam, anything more than 422 would be overkill. Not the case for F950 HDCam SR. I stand corrected. Thanks. steve covello double wide post


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R.Howard
Re: Luminance Shift with 10bit RGB
on Feb 2, 2007 at 5:07:38 am


Yes the luminance issued showed up in a 444 project we helped out with last year, without pointing fingers we did discover what the reason or problem was and I'm sure there is some documentation out there for anybody doing a search. Nobody wants to step up to the plate and admit who's at fault over this one but there are several solutions out there to get around this.

444 is not overkill at all in the right environment and quickly becoming the norm.

Cheers,
Ramona

Ramona Howard
SpectSoft, LLC
593 Hi-Tech Parkway Suite B
Oakdale, CA 95361
Phone: 209.847.7812 extension 104
Fax: 209.847.7859
http://www.spectsoft.com

RaveHD - Changing the way you think about HD


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Joe Murray
Re: Luminance Shift with 10bit RGB
on Feb 3, 2007 at 3:58:00 am

Ramona, that's an almost helpful post...if there's information "out there" can you point us to it with a link? Or elaborate? Would be nice to learn from your experience -

Please?

Joe Murray
http://www.editatjoes.com


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R.Howard
Re: Luminance Shift with 10bit RGB
on Feb 4, 2007 at 8:37:07 pm

Joe,

We took the Sin City stuff off our website but I'm sure there are still bits out there with what we discovered with clipping when working on the development for this project (There are only a few articles that mention this problem). With 4:4:4 you can not assume everyone is doing it the correct way, even at a hardware level.(there is a huge debate as to what is the correct way, once again proving that film and video are very different)

We have discovered that some products will clip without letting you know and we have taken the clip or no clip option approach rather than just clipping as so many of our projects are out to film where broadcast levels have no place.

Hopefully that is enough for you to narrow the issue down and to help you solve your problem.

Cheers,
Ramona



Ramona Howard
SpectSoft, LLC
593 Hi-Tech Parkway Suite B
Oakdale, CA 95361
Phone: 209.847.7812 extension 104
Fax: 209.847.7859
http://www.spectsoft.com

RaveHD - Changing the way you think about HD


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