getafixx wrote:Yeah, without the resistors. Y is running from the multiout pin 7.
Thanks... ^^
I'm having a hard time understanding the logic behind it though.
Just a few random thoughts. Correct me if I'm wrong please...
The transistor on B boosts B minus Y, not just B.
The transistor on R boosts R minus Y, not just R.
Fact that the transistors boost the blue and red signals minus Luma, and not just the blue and red signals, means both blue and red output stay pretty much the same.
Green is more saturated because of the transistors on both the Pb and Pr lines.
Boosting or restricting Y only affects brightness and the green signal, not the blue and red one.
Is there a formula to calculate the green signal?... I think knowing that is essential to understanding what's going on here...
I hope I've got some of that right. If not, please enlighten me...

EDIT:
Shit. Just reread my comment, and... it doesn't make sense at all...

Found this on Wikipedia though:
While luma is more often encountered, (photometric) luminance is sometimes used in video engineering when referring to the brightness of a monitor. The formula used to calculate luminance uses coefficients based on the CIE color matching functions and the relevant standard chromaticities of red, green, and blue (e.g., the original NTSC primaries, SMPTE C, or Rec. 709). For the Rec. 709 primaries, the linear combination, based on pure colorimetric considerations and the definition of luminance is:
Y = 0.2126 R + 0.7152 G + 0.0722 B
I guess that's the best place to start explaining how everything works?...