Re: Varicam or HD

[Jef Huey <jhuey(at)henninger.com>]

Victor,

Great example. I remember seeing that awhile ago. While this would seem 
to say that I was not correct in saying sampling is about the quality of 
_individual _pixels, let me ask - based on these images, would you 
rather key a 4:2:2 or 4:1:1 image? 4:2:2 probably because there are more 
unique descriptions of the image COLORWISE in the 4:2:2 image. Since 
keying is all about edges, 4:2:2 has more info for the edges. So that 
said it would seem that the Varicam would be better for color keying.

But then you have to take in the pixel grid size issue. And that would 
have to fall into the what is the final product and what manipulations 
will I do in the intermediate steps question.

Jef



Victor Wolansky wrote:

> Jef, look what I found, I think is very good to understand the 4:2:2 
> 4:4:4 99:99:99 thing... :-)
>
> I don’t know if the email is going to keep the format, if not. This is 
> the link
>
> http://www.answers.com/topic/ycbcr-sampling
>
> As you can see the 4:2:2 or 4:4:4, is the sampling of a group of 
> pixels and not the sampling of each individual pixel.
>
> Victor Wolansky
>
> DS VFX Artist
>
> WEBsite
>
> Demo Reel
>
> 815 Slaters Lane
>
> Alexandria. VA.
>
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>
> -----Original Message-----
> From: owner-ds(at)Softimage.COM [mailto:owner-ds(at)Softimage.COM] On Behalf 
> Of Jef Huey
> Sent: Monday, August 01, 2005 5:38 PM
> To: DS(at)Softimage.COM
> Subject: Re: Varicam or HD
>
> Victor,
>
> Like I said, ignore pixel count FOR THE TIME BEING.
>
> 4:2:2 and 3:1:1 is about how much information EACH pixel has. It has
>
> nothing to do with how many pixels are on a line.
>
> 1920 x 1080 is a description of how many pixels wide by how many pixels
>
> high an HD image is.
>
> Each of those pixels could have been captured as EITHER 4:2:2 or 3:1:1.
>
> Do you see what I am talking about here? So no, a 300x300 4:4:4 image
>
> is not better than a 1920x1080 4:2:2 image.
>
> But the individual pixels of the 300x300 have more color information
>
> EACH than the later image. And you would get a better key from the
>
> 300x300 image.
>
> At least that is how I understand it. ;) All this said, testing is
>
> and good lighting is the key. PUN!!
>
> Jef

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