Re: PC CuSeeMe codec

John Carey (john@carey.com)
Thu, 9 Mar 1995 08:43:26


Michel,

Very nice explaination. Thank you.

I would like to point out that the prior to TV transmission, YUV which is a
discrete three signal component format is encoded into composite YIQ. Y is
still luminance, but the U and V portions of the signal are encoded using
schemes called Inphase and Quadrature so that the resulting signal can be
broadcast on one carrier with audio on a subcarrier. That's TV in a nutshell.

I haven't thought about this stuff for some time now. Thanks for jogging my
memory, and my apologies to those who are uninterested in this stuff.

John (john@carey.com)

p.s. I can't for the life of me remember for what words U and V actually
stand. Does anyone out there know?

jwc

>All PC users,

>My codec also supports Indeo, but only the so called Indeo YVU9 format,
>which is not the Intel Indeo compression format. The YVU9 is not a real
>compression format, it is simply the format in which most video capture
>boards store the video pictures in their internal memory. It is the format
>used to code a TV picture for transmission by the broadcasters. Y stands for
>luminance info, V and U representing the color info and beeing equal to
>-(R-Y) and -(B-Y). The interest of this format is that it is compatible with
>B/W receivers. In the YVU9 format, the chrominance info (V and U) are stored
>after the Y info in memory, and there is only one chrominance info (one V
>and one U) for each block of sixteen pixels (4x4 block). Each elementary
>info is digitized in 8 bits. The interest of this format is that, as it is
>the native format for the dig cards, saving pictures in this format is
>faster because the driver accompanying the card does not have to translate
>to the RGB format before storing on disk. Once again, this format has
>nothing to do with the full Intel Indeo compression format.

>Hope all this is clear.

>CU,

> Michel
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> Michel Carleer

>Laboratoire de Chimie Physique Moleculaire Phone : +32-2-650.24.25
>Universite Libre de Bruxelles CPi-160/09 Fax : +32-2-650.42.32
>50 Av F.D. Roosevelt e-mail: mcarleer@ulb.ac.be
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