Subject: Re: Recording to VHS
From: Ernie Wright <[email-masked]>
To: The LightWave mailing list <[email-masked]>
Date: Tue, 30 Apr 1996 14:40:04 -0400 (EDT)

Sean Moyer wrote:

> Although (255,255,255) might work with some encoders, using the Abekas
> Diskus we've found that any white over about 220,220,220 is prone to
> tearing, and because the white video signal is a harmonic of the audio
> sub-carrier, if I'm not mistaken, 255,255,255 whites are discouraged
> because they can cause audio buzzing on consumer televisions.

Sometimes it's a wonder to me that TV works at all.

>    PBS is particularly strict. In computer graphic segments of a PBS
> show, they do not allow white levels of above 90 IRE, and the combined
> chroma and luminance cannot exceed 100 ire.

This is a pretty tough standard.  (137,137,0) (yellow) and (0,137,137)
(cyan) would both fail (as will anything on these HSV axes with values
above 137, or about 53%).  I wonder if this has anything to do with PBS
being carried on UHF in most areas.  Or maybe they're just CGI-averse,
as their remarks about their most recent (non-CGI) logo might suggest.

- Ernie

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