RGB or YUV at DVinfo.net

Harikrishnan Ponnurangam · March 16th, 2006, 06:26 PM

I have a question on dvcprohd format on HVX200.

Does HVX200 record in 4:2:2 RGB or converts to YUV and records it on the P2 card?

I read a article on about the color spacing and sony HDC-F950 4:4:4 RGB.

What is the difference between dvcprohd and HD? If there is a thread already on this question can somebody refer it here.

Graeme Nattress · March 16th, 2006, 07:08 PM

In RGB, each pixel has an R, a G and a B value. This makes for an awful lot of data.

In component video, RGB is tranformed to Y'CbCr, where Y is luma, and Cb and Cr are two chroma difference components. This is often called YUV, but that is wrong. It's really Y'CbCr.

When in Y'CbCr you can reduce the resolution of the chroma without effecting the appearance of the video too much, hence 4:2:2 meaning that Cb and Cr are half the horizontal resolution of the luma.

That means, in DVCproHD, for each two record pixels of luma, there is just one pixel of Cb and one of Cr.

4:4:4 means that for each pixel, there is each component recorded. 4:4:4 can be RGB, and RGB must be 4:4:4 by definition. You can also get 4:4:4 Y'CbCr, but that's not too common.

Graeme

Harikrishnan Ponnurangam · March 16th, 2006, 09:16 PM

You mean a change in Luma will be very sensitive to the human eye or in other terms there will be a drastic change in the quality of video?

So obviously dvcproHD is not recording in RGB values it records in Y'CbCr 4:2:2

Makes a lot of sense.

Graeme Nattress · March 16th, 2006, 09:20 PM

Most video formats record Y'CbCr. I think one of the that can do RGB is HDCAM SR.

DVCproHD is indeed using 4:2:2 Y'CbCr.

You're right about the human eye being more sensitive to luma than chroma!

Graeme

Harikrishnan Ponnurangam · March 20th, 2006, 01:27 PM

Just want to say RGB recording rocks. You can do whatever you want with a RGB image. I got a frame of RGB image and tried to color correct it in Adobe photoshop. Wow i can do so many things with that image. I want a F950.

March 16th, 2006, 06:26 PM	#1
Harikrishnan Ponnurangam Regular Crew Join Date: Mar 2005 Location: St.Louis, USA Posts: 145	RGB or YUV I have a question on dvcprohd format on HVX200. Does HVX200 record in 4:2:2 RGB or converts to YUV and records it on the P2 card? I read a article on about the color spacing and sony HDC-F950 4:4:4 RGB. What is the difference between dvcprohd and HD? If there is a thread already on this question can somebody refer it here.

March 16th, 2006, 07:08 PM	#2
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	In RGB, each pixel has an R, a G and a B value. This makes for an awful lot of data. In component video, RGB is tranformed to Y'CbCr, where Y is luma, and Cb and Cr are two chroma difference components. This is often called YUV, but that is wrong. It's really Y'CbCr. When in Y'CbCr you can reduce the resolution of the chroma without effecting the appearance of the video too much, hence 4:2:2 meaning that Cb and Cr are half the horizontal resolution of the luma. That means, in DVCproHD, for each two record pixels of luma, there is just one pixel of Cb and one of Cr. 4:4:4 means that for each pixel, there is each component recorded. 4:4:4 can be RGB, and RGB must be 4:4:4 by definition. You can also get 4:4:4 Y'CbCr, but that's not too common. Graeme __________________ www.nattress.com - filters for FCP

March 16th, 2006, 09:20 PM	#4
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	Most video formats record Y'CbCr. I think one of the that can do RGB is HDCAM SR. DVCproHD is indeed using 4:2:2 Y'CbCr. You're right about the human eye being more sensitive to luma than chroma! Graeme __________________ www.nattress.com - filters for FCP

March 16th, 2006, 09:16 PM	#3
Harikrishnan Ponnurangam Regular Crew Join Date: Mar 2005 Location: St.Louis, USA Posts: 145	You mean a change in Luma will be very sensitive to the human eye or in other terms there will be a drastic change in the quality of video? So obviously dvcproHD is not recording in RGB values it records in Y'CbCr 4:2:2 Makes a lot of sense.

March 20th, 2006, 01:27 PM	#5
Harikrishnan Ponnurangam Regular Crew Join Date: Mar 2005 Location: St.Louis, USA Posts: 145	Just want to say RGB recording rocks. You can do whatever you want with a RGB image. I got a frame of RGB image and tried to color correct it in Adobe photoshop. Wow i can do so many things with that image. I want a F950.