Andrew, Pierre:

After some testing, I checked into GIT Andrew's waveform mod to add the additional IRE 92.2% + 6.3% lines for the waveform. Interesting discussion - past and present.

> I had forgotten all this complexity and the multiple distinctions
> between the IRE values that only concern analog video and the Waveform
> monitor (VideoScope) of Cinelerra-GG which only calculates % of the
> digital 0-255 scale.
>
> It's not easy to understand that a YCbCr source image (16-235)
> corresponds to 6.3-92% on the Waveform grid, especially since there are
> no visual cues on the grid to indicate this and to show the video level
> overruns that could cause problems depending on the destination of the
> editing ...

I added (by trial and error!) those two lines ... they assume
WAVEFORM_DIVISIONS 12

but I guess they only valid for some types of footage and some setting of mpeg/jpeg toggle ....