Re [PD] pix_freeframe

[Mathieu Bouchard]

On Thu, 31 Aug 2006, padawan12 wrote:

> I'm not following this thread but nice explanation. So YUV in anything 
> other than 4 4 4 is basically "compressed video" ?

Depends on who you ask, what's the meaning of "compression"... it's 
certainly "subsampled", as in, when people say DV is 720x480, that's not 
what it is for real, only the Y channel is like that, and the UV channels 
are in 360x480.

basically "444" is uncompressed, "422" has the UV in half-width, "411" has 
the UV in quarter-width, and "420" has the UV in both half-width and 
half-height.

if you're in 8 bits per value, then "444" is 24 bpp, "422" is 16 bpp, and 
the others are 12 bpp, but those "bits per pixel" are assuming a "pixel" 
is defined only in terms of the Y channel. If you do it only in terms of 
UV channels, then everything is reversed, as "444" is 24 bpp, "422" is 32 
bpp, and the others are 48 bpp.

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| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada