Re: Reliable broadcast colors possible?

There are some "grading" monitors that have scopes built into them -- very few have gamut warning systems, though. Fewer that are actually useful and/or accurate.

You're right about different systems flagging different things because there are different issues with the component video streams and colourspaces themselves. What is "legal" gamut in RGB may not make the trip in YCbCr, and may not be compatible with YIQ ("composite broadcast").

In RGB its virtually impossible to have zero luminance (only one combination, R=G=B=0), but you can do that with many combinations of colour components in both YCbCr and YIQ or YUV, which can also generate negative values, easily. To adequately monitor "Broadcast Safe", you really need a system that is looking at composite emulation, where the additive effect of luminance and chrominance are being evaluated. Innocent amounts can combine to put you out of bounds. You are allowed up to 102 IRE in luminance and up to 120 IRE Y+C... but for example, 20 units of yellow, for instance is going to put you over, and that's only half of a "normal" amount of saturation corresponding to 40 IRE burst. You can't even generate that in RGB, but it would be trivial in a grading application working in YCbCr.

Beware of software solutions.

jPo


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