[sane-devel] backend Kodak i260 Image depth 48 bits stream. How is coded?

[m. allan noah]

thanks daniel- now this begins to make sense:

http://wiki.multimedia.cx/index.php?title=YCbCr_4:2:0 says:

"Since 6 bytes, or 48 bits represent 4 pixels, an average of 12 bits
are required to represent a single pixel in this scheme."

so the 48 bit depth in the set window command is for each 2x2 block.

i guess they dont put all 4 Y samples together cause they are on
different scanlines.

if you look at the slope on the edge of the taillight you can see that
each pair Y samples are switched, as you have stated.

allan

On Sat, Aug 30, 2008 at 5:54 PM, Daniel Glöckner <daniel-gl at gmx.net> wrote:
> The picture is in YCbCr 4:2:0 format.
>
> 0. byte: Y(1,0)
> 1. byte: Y(0,0)
> 2. byte: Cr(0.5,0.5)
> 3. byte: Cb(0.5,0.5)
>
> 4. byte: Y(3,0)
> 5. byte: Y(2,0)
> 6. byte: Cr(2.5,0.5)
> 7. byte: Cb(2.5,0.5)
> :
> :
> 4796. byte: Y(2399,0)
> 4797. byte: Y(2398,0)
> 4798. byte: Cr(2398.5,0.5)
> 4799. byte: Cb(2398.5,0.5)
>
> 4800. byte: Y(1,1)
> 4801. byte: Y(0,1)
>
> 4802. byte: Y(3,1)
> 4803. byte: Y(2,1)
> :
> :
> 7198. byte: Y(2399,1)
> 7199. byte: Y(2398,1)
>
> repeat for the following 7200 byte blocks
>
> The chroma offset is guessed.
> It would need some sharp colorful edges to verify that.
>
>  Daniel
>
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