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deep color

post #1 of 6
12/4/11 at 9:27am
Thread Starter 
I would like to understand about deep color. Are blu-ray media encodes video with deep color? What is meant by 8 bit, 12 bit, 24 bit deep color?

My projector (JVC RS40) manual says, it does not show deep color when input Y, cb,cr is 4:2:2. Does it mean r 4bits for Y, 2 bits for cb and 2 bits for red implies no deep color.

I also read in another thread that "10-bit, 4:2:2/4:4:4". How 4:2:2 and 4:4:4 are 10 bit.

Appreciate if anybody can help me enlightened on this.
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post #2 of 6
12/4/11 at 9:39am
8-bit (and therefore 24-bit which is nothing but 3x 8-bit) is not deep color. 10-bit and 12-bit (30-bit / 36-bit) are called deep color.

There are no commercial media available in deep color. Blu-Ray media is currently encoded at 8-bit only.

Some Blu-Ray players offer color-interpolation (e.g. Sony's superbitmapping). Video processors can also offer internal 10-bit processing, so if you have a deep color connection, enabling deep color on both the VP's output and the display's or beamer's input helps to avoid another downconversion to 8-bit.

4:2:2 / 4:4:4 has nothing to do with the color depth, but it's the actual pixel resolution. 4:4:4 means full resolution for the luma channel (Y) and both color channels, while 4:2:2 is a full resolution luma channel and color channels at half resolution.

Your beamer (and actually most modern displays) will allow you to feed 10-bit deep color in 4:2:2 resolution, while 4:4:4 is only supported at 8-bit color depth.
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post #3 of 6
12/4/11 at 1:00pm
Thread Starter 
Quote:
Originally Posted by Fudoh View Post

8-bit (and therefore 24-bit which is nothing but 3x 8-bit) is not deep color. 10-bit and 12-bit (30-bit / 36-bit) are called deep color.

There are no commercial media available in deep color. Blu-Ray media is currently encoded at 8-bit only.

Some Blu-Ray players offer color-interpolation (e.g. Sony's superbitmapping). Video processors can also offer internal 10-bit processing, so if you have a deep color connection, enabling deep color on both the VP's output and the display's or beamer's input helps to avoid another downconversion to 8-bit.

4:2:2 / 4:4:4 has nothing to do with the color depth, but it's the actual pixel resolution. 4:4:4 means full resolution for the luma channel (Y) and both color channels, while 4:2:2 is a full resolution luma channel and color channels at half resolution.

Your beamer (and actually most modern displays) will allow you to feed 10-bit deep color in 4:2:2 resolution, while 4:4:4 is only supported at 8-bit color depth.

Thanks for quick reply. Now I understood it better. The question I have how is it possible to use equal 3x8 bit(y, cb,cr) for 3 channels with unequal resolution 4:2:2.
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post #4 of 6
12/4/11 at 3:10pm
why not ? the bit-deph just says how many different "shades of colors" are available for a single pixel in the image (in the particular channel). It doesn't matter if the resolution is 480p, 720p, 1080i or 1080p or if one of the channels has a higher resolution than the others.
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post #5 of 6
12/5/11 at 11:07am
Thread Starter 
Quote:
Originally Posted by Fudoh View Post

why not ? the bit-deph just says how many different "shades of colors" are available for a single pixel in the image (in the particular channel). It doesn't matter if the resolution is 480p, 720p, 1080i or 1080p or if one of the channels has a higher resolution than the others.

Thanks for reply. You are referring 4:2:2 or 4:4:4 as resolution and different shades of color (cb,cr) and luma(y) as color depth. Is it right?

I also read little more on 4:2:2 and this is what my understanding. If image is sampled for 4x4 pixels and sampled at resolution of 4:2:2, then there are 4x4 y channels and 4x2 channels for each cb, cr. Am I right?


Assuming that each channel (y,cb,cr)may need 8 for basic or more than 8 for deep color. I want to make sure that if 4x4 image is stored in

1. 4:2:2 at 10 bit deep color. The number of bits are
4x4x10 = y (first number tells number of rows, second number how many pixels are used in each row)
+
4x2x10 =cb
+
4x2x10 = cr


2. 4:4:4 at 8 bit. The number of bits are
4x4x8 = y
+
4x4x8 =cb
+
4x4x8 = cr

Does it makes sense?
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post #6 of 6
12/5/11 at 11:18am
You're losing me, sorry. You probably mean the right thing though. It's pretty well explained in the Wiki article about color subsampling: http://en.wikipedia.org/wiki/Chroma_subsampling

If you take the Y channel on it's own, then the "4" doesn't mean anything. Y is always full resolution (e.g. 1920x1080p). The 4 only makes sense in comparison to the other channels, where 4:2 means that the Cb channel has HALF the resolution of the Y channel.

If you want to calculate bitrates, it's simply RESOLUTION x COLOR DEPTH for the Y channel und RESOLUTION x COLOR DEPTH x (1 / SAMPLING RATIO) for the other channels.

E.g. for Y : 1920x1080x10-bit and 1920x1080x10-bit x 0.5 for the Cb channel.
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