Re: PC CuSeeMe codec

M. Carleer (mcarleer@ulb.ac.be)
Thu, 09 Mar 1995 19:15:35 +0100


>
>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.
>

Hi John,

Thanks for the additional info, which is true but only for the US. I didn't
want to got into the next step of how the three Y, V and U signals are used
to modulate the HF carrier, because this is where the different NTSC, PAL,
SECAM and their numerous flavors all differ. Your explanation only pertains
to NTSC.

One additional piece of comment: the reason why most of the video capture
cards manufacturers use the YVU format is that a Dutch company named Philips
developped digitizing circuits using this format to include in their top
range TV sets. Which means mass production, which in turn means cheap prices.

OK, OK, sorry on my behalf also if this seems boring and out of the subject.

CU :-)

Michel
----------------------------------------------------------------------------
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
B-1050 Bruxelles
----------------------------------------------------------------------------