Color Reproduction and Scarlet

[digitalnirvana9]

I really like the HVX 200 because of the 422 color space. The colors are much deeper and nuanced than HDV and the composites are much cleaner IMHO. So my question is: I know that RED works outside of the usual color space system. Will Scarlet be able to reproduce the rich colors of the HVX if it uses a lesser rez system (2K?) but still bases its other attributes on RED for capture, editing and color correction? This might be a good question for Barry Green....Thanks, Norman

[Peter Majtan]

For Scarlet to be "truly" revolutionary I would expect it to capture 4:4:4 RGB, nothing less... I think, let me correct myself- I KNOW that the technology has matured enough to abolish "compromising" on color information...

Besides - native 4:4:4 RGB is much easier to process and actually needs less "electronics magic" to work. This goes even more for post...

The question we should be asking is if Scarlet (and a new version or RED ONE) is going to capture HDRI, or at least 16-bit (8:8:8)? This is not far-fetched, believe me...

[Stephen Gentle]

For Scarlet to be "truly" revolutionary I would expect it to capture 4:4:4 RGB, nothing less... I think, let me correct myself- I KNOW that the technology has matured enough to abolish "compromising" on color information...

Besides - native 4:4:4 RGB is much easier to process and actually needs less "electronics magic" to work. This goes even more for post...

The question we should be asking is if Scarlet (and a new version or RED ONE) is going to capture HDRI, or at least 16-bit (8:8:8)? This is not far-fetched, believe me...

There is no 4:4:4 - there is only RAW

[Bruce Allen]

For Scarlet to be "truly" revolutionary I would expect it to capture 4:4:4 RGB, nothing less... I think, let me correct myself- I KNOW that the technology has matured enough to abolish "compromising" on color information...

Besides - native 4:4:4 RGB is much easier to process and actually needs less "electronics magic" to work. This goes even more for post...

The question we should be asking is if Scarlet (and a new version or RED ONE) is going to capture HDRI, or at least 16-bit (8:8:8)? This is not far-fetched, believe me...

Peter

Two things: you can't get 4:4:4 from a single CCD, unless you are oversampling heavily (eg a Red One probably produces 4:4:4 2K).

4:2:2, 3:1:1 etc ratios do not mean bits per channel. They are just ratios of luma : chroma.

Agree, HDRI is hopefully in our future! Although it is currently too much of a tradeoff. I'd be happy with "just" being competitive with film.

Bruce Allen
www.boacinema.com

[Peter Majtan]

Peter

Two things: you can't get 4:4:4 from a single CCD, unless you are oversampling heavily (eg a Red One probably produces 4:4:4 2K).

Dude - RED ONE is not CCD - it is CMOS!!! (However this also makes no difference to 4:4:4)
Also I don't get Your point - You say You can't get 4:4:4 and You say "Red One probably produces 4:4:4 2K" :unsure:

4:2:2, 3:1:1 etc ratios do not mean bits per channel. They are just ratios of luma : chroma.

Yes when You are talking about YUV (more precisely Y'CbCr). In RGB world 4:4:4 refers to 8-bit RGB and 8:8:8 refers to 16-bit RGB - just ask anyone with Sony Vialta film scanner. I was part of the team who pull the 8:8:8 data out of it...

Agree, HDRI is hopefully in our future! Although it is currently too much of a tradeoff. I'd be happy with "just" being competitive with film.

HDRI is not a tradeoff at all. I have designed and outlined HDRI capturing system capable of recording HDRI just like a "normal" camera's do. In-fact it is much easier the most people think. Just "the market is not ready yet" BS the big 5 is giving us is stopping HDRI from happening...

Jim - if You are listening - I will be more then happy to share my HDRI capture design with You guys, if You want to implement it to RED ONE, Scarlet, or any other shade of red You will develop in the future...



Bruce Allen
www.boacinema.com[/QUOTE]

[Peter Majtan]

There is no 4:4:4 - there is only RAW

Once again - 4:4:4 and RAW are two different things, altho clearly related. RAW is the format the "raw" data from the sensor are stored. 4:4:4 is the sampling of the data. Depending on the "RAW" format one could then extract different sampling data from it.

What really matters is how RED "interprets" and "stores" raw data from the sensor. Contrary to what others may think You don't need 3 sensors (altho it does helps heaps to have individual sensors capturing separate color channels) to get 4:4:4 out of a sensor - be it CCD or CMOS. Just look at still cameras - You get pure "4:4:4" or even "6:6:6" and "8:8:8" RGB still images - no subsampling what so ever! But that is another topic...

Given that Bayer pattern has double of green pixels as compared with red and blue - people tend to think that this somehow interprets as 4:2:2. It does and does not. First of all - in YUV world - 4:2:2 does not translate as 4R:2G:2B - which coincidently is the ratio of the colors in the Bayer pixel pattern. Here are the common systems in use today:

4:4:4 Y'CbCr
Each of the three Y'CbCr components have the same sample rate.
(no subsampling) - can be easily translated to RGB format without any loss of quality.

4:4:4 RGB implicitly does not have any chroma subsampling at all.
Some SONY formats can record 4:4:4 RGB over dual-link HD-SDI.
SONY Vialta can actually do 8:8:8 RGB (16-bit)...

4:2:2
The two chroma components are sampled at half the sample rate of luma, so horizontal chroma resolution is cut in half. This reduces the bandwidth of a video signal by one-third with little to no visual difference.

It is in the "Y'CbCr" world, where the decision was made to trade of chroma in favor of luma (due to data bandwidth limitations and human eye greater sensitivity to contrast rather the color). When capturing the luma (or brightness of the scene) - good quality cameras use data from all "four" (GGBR - having double of green pixels) adjacent sensor pixels, as color is irrelevant for the interpretation of the exposure to the sensor area for luma calculations. Also our eyes are more sensitive to green light, than to red or blue - this was the reason for Bayer pattern to be GGBR, not RRBG or BBRG...

I hope this clear things up a little...

[Peter Majtan]

Agree, HDRI is hopefully in our future! Although it is currently too much of a tradeoff. I'd be happy with "just" being competitive with film.

Just one more thing:

It is precisely HDRI (and only HDRI) that can make digital competitive with analog film. Digital has already matched (and exceed in case of 35mm) the resolution of an image. You can also use the "same" glass and any other accessories. The only remaining mountain to scale is the high dynamic range of analog film. Without HDRI we will never catch up...

[Graeme Nattress]

First, I'd argue against 4:2:2 giving better colour (deeper and nuanced) than HDV (which is 4:2:0) because contrary to popular usage of the term, 4:2:2 is NOT a colour space. A colour space is something like Adobe RGB 1998, or REC709, or sRGB etc. 4:2:2 is chroma sub-sampling notation.

I'm not going to talk about Scarlet here for obvious reasons....

First, 4:4:4 is very rare. Some cameras that claim it have offset sensors (pixel shift) which although can improve things at 4:2:2, makes things worse at 4:4:4. I've seen it in dpx files from said cameras where the colours just never seem to line up right, always having a pixel offset. Even cameras that do have 4:4:4 will find it compromised by the prism, lens etc.

The RED One has one of the nicest, most natural, unforced colour reproduction I've seen. I've obviously seen a lot of footage on my system over the years, from high end and low end cameras, and RED really does look very nice, and I'm not just saying that because of my involvement in the way RED ONE generates colour. The basic decode of colour on the RED ONE is very under saturated. That's because it captures a very wide gamut of colours, one of the benefits of our RAW approach. This is a good thing!

Chroma sub-sampling notation is a measure of by how much you reduce the resolution of the chroma components when the image is in YCbCr form. "least 16-bit (8:8:8)? ", chroma sub-sampling notation does not refer, in any way, to bit depth, so that question is meaningless. I see your comment that a scanner uses such notation through for 16bit transfer, but quite frankly, that's a pure abuse of the notation and not valid in any way. Remember when HD was referred to as 22:11:11 because of the higher sampling base frequency than SD?

Also, it is not correct or proper to attribute a RAW system with a chroma sub-sampling notation. That's because the Bayer pattern used functions completely differently to reduce the image data, and, as the light hits the sensor, rather than dealing with decimating transformed data after capture.

When we reconstruct RAW, we aim to reconstruct back to full RGB, and that's what it looks like.

YCbCr 4:2:2 say, is not designed to be reconstructed back to up 4:4:4, but to be dealt with and displayed as is. Sure, we can develop algorithms to take it back up to a seemingly plausible 4:4:4 (guess who sells plugins to do that!) but RAW mosaic data was designed for full RGB reconstruction, as in the Bayer pattern and RAW data are designed in tune with the eventual reconstruction to RGB, as a fully cohesive system.

[Bruce Allen]

Just one more thing:

It is precisely HDRI (and only HDRI) that can make digital competitive with analog film. Digital has already matched (and exceed in case of 35mm) the resolution of an image. You can also use the "same" glass and any other accessories. The only remaining mountain to scale is the high dynamic range of analog film. Without HDRI we will never catch up...

Agreed. It's just that I'd be happy with Medium Dynamic Range, let alone High. I'd currently characterize digital sensors as Low Dynamic Range...

Yes when You are talking about YUV (more precisely Y'CbCr). In RGB world 4:4:4 refers to 8-bit RGB and 8:8:8 refers to 16-bit RGB - just ask anyone with Sony Vialta film scanner. I was part of the team who pull the 8:8:8 data out of it...

So you mean x:x:x means one thing for Y'CbCr and something else for RGB? What a mess!

Looks to me like Sony has just twisted the terminology for marketing purposes.

If so, it's a horrible misuse of the : symbol, which used to imply a ratio.

Peter, let us know more about your HDRI design. What I've seen so far always involves compromises on overall sensitivity / price / feasability, etc. I'm sure it can be done in the future, just we are not quite there yet. We've had many conversations about this in the past.

To go back to the original point, how do you expect Scarlet to capture "native 4:4:4 RGB" with a Bayer sensor? Or are you talking about something other than a Bayer sensor (which we have also discussed many times)?

Again, I don't think Red One captures something equivalent to "native 4:4:4 RGB" at 4K - but when you scale it down to 2K you can make 4:4:4 quality images. Not a complex concept.

Bruce Allen
www.boacinema.com

[Bruce Allen]

Chroma sub-sampling notation is a measure of by how much you reduce the resolution of the chroma components when the image is in YCbCr form. "least 16-bit (8:8:8)? ", chroma sub-sampling notation does not refer, in any way, to bit depth, so that question is meaningless. I see your comment that a scanner uses such notation through for 16bit transfer, but quite frankly, that's a pure abuse of the notation and not valid in any way. Remember when HD was referred to as 22:11:11 because of the higher sampling base frequency than SD?

Yaay, Graeme agrees.

Bruce Allen
www.boacinema.com