This thread has so many different topics being discussed at the same time.
That old post from me that you’ve linked is outdated. A lot of the older things in my thread are messed up to some degree. The reason why I made my posts sound so confident was because no one else was sharing presets that simulate these red-oversaturating decoder chips.
and yes, the data sheet for the CXA2025AS has R-Y’s gain relative to B-Y much higher than the standard. Most other NTSC chips have R-Y’s relative gain extra high too, as you can see in the big long list below. These are all from consumer CRTs though, so we don’t know if developers’ PVMs did the same thing. We have no data for what developers’ PVMs did; they could be doing plain, unmodified SMPTE C decoding for all we know, without these oversaturated reds.
Big long list
const float demodulatorinfo[] [2][3] = {
// Index 0
// Dummy -- No color correction!
// Use this for content in the PAL or SMPTE-C that did not use color correction.
{
{90, 236, 0}, // angles (degrees)
{0.56, 0.34, 1.0} // gains
},
// Index 1
// CXA1464AS (JP)
// Used in Sony Trinitron ~1993 - ~1995
{
{98, 243, 0}, // angles (degrees)
{0.78, 0.31, 1.0} // gains
},
// Index 2
// CXA1465AS (US)
// Used in Sony Trinitron ~1993 - ~1995
{
{114, 255, 0}, // angles (degrees)
{0.78, 0.31, 1.0} // gains
},
// Index 3
// CXA1870S (JP mode)
// Used in Sony Trinitron ~1996
{
{96, 240, 0}, // angles (degrees)
{0.8, 0.3, 1.0} // gains
},
// Index 4
// CXA1870S (US mode)
// Used in Sony Trinitron ~1996
{
{105, 252, 0}, // angles (degrees)
{0.8, 0.3, 1.0} // gains
},
// CXA2061S (JP and US modes)
// Used in Sony Trinitron ~1997 - ~1999
// But datasheet doesn't state axis info! Possibly similar to CXA2060BS below.
// CX20192
// Used in Sony Trinitron "late 80's/early 90's"
// Can't find datasheet
// CXA1013AS
// Used in Sony Trinitron ~1993
// Can't find datasheet
// CXA1865S
// Used in Sony Trinitron
// Apparently an upgrade to CXA1465AS
// Can't find datasheet
// Demodulators above this point were *probably* all designed with the same phosphors in mind
// They can all be found in a cluster of Trinitron models with overlapping tubes and/or demodulators.
// And those phosphors are *probably* the ones in the Trinitron P22 gamutpoints constants above.
// Demodulators below this point *might* be designed for use with the same phosphors,
// or Sony might have changed phosphors at some point -- I don't know.
// Index 5
// CXA2060BS (JP mode)
// Used in Sony Trinitron ~??? (probably around 1997)
{
{95, 236, 0}, // angles (degrees)
{0.78, 0.33, 1.0} // gains
},
// Index 6
// CXA2060BS (US mode)
// Used in Sony Trinitron ~??? (probably around 1997)
{
{102, 236, 0}, // angles (degrees)
{0.78, 0.3, 1.0} // gains
},
// Index 7
// CXA2060BS (PAL mode)
// Used in Sony Trinitron ~??? (probably around 1997)
{
{90, 227, 0}, // angles (degrees)
{0.492111/0.877283, 0.34, 1.0} // gains
},
// Index 8
// CXA2025AS (JP mode)
// Used in Sony Trinitron ~1997
{
{95, 240, 0}, // angles (degrees)
{0.78, 0.3, 1.0} // gains
},
// Index 9
// CXA2025AS (US mode)
// Used in Sony Trinitron ~1997
{
{112, 252, 0}, // angles (degrees)
{0.83, 0.3, 1.0} // gains
},
// Index 10
// CXA1213AS
// Used in Sony Trinitron(?) ~1992
// Does not appear to have distinct JP and US modes
// It's possible this chip is either JP or US and there exists another chip number for the other.
// Theoretially, blue at a non-zero angle should mean that gains need renormalized,
// but I suspect they were not in practice.
// (0.77, 0.3, 1.0 is more similar to other chips than 0.74, 0.28, 0.96
{
{99, 240, 11}, // angles (degrees)
{0.77, 0.3, 1.0} // gains
},
// Index 11
// TDA8362
// Used in Hitachi CMT2187/2196/2198/2199
// Very likely match to the Hitachi P22 phosphor constants above.
// This chip does not have distinct JP and US modes, so one color correction matrix used for both apparently.
// It's also not clear if televisions sold in the US and Japan shared one whitepoint.
// These values are pretty wild (especially red gain). Not sure if gains should be renormalized for blue at non-zero angle. (Probably should since not doing it looks pretty bad.)
{
{100, 235, -10}, // angles (degrees)
{1.14, 0.3, 1.14} // gains
},
// Index 12
// Unknown chip used in 1989 RCA ColorTrak Remote E13169GM
// US model
// calculated from measurements by Patchy68k
// https://github.com/ChthonVII/gamutthingy/issues/1#issuecomment-2672961597
{
{94.5488524399, 255.376054365, 0}, // angles (degrees)
{0.806809988011, 0.295471057738, 1.0} // gains
},
// Index 13
// TA7644BP
// Used in 1985 Toshiba Blackstripe CF2005
// https://github.com/ChthonVII/gamutthingy/issues/1#issuecomment-2679838025
{
{107, 240, 0}, // angles (degrees)
{0.95, 0.31, 1.0} // gains
},
// Index 14
// TA7644BP Measured
// Computed from measurements of 1985 Toshiba Blackstripe CF2005
// https://github.com/ChthonVII/gamutthingy/issues/1#issuecomment-2700255641
// Unit was very deteriorated.
// Discrepancies from datasheet may be due to poor condition, or datasheet being inaccurate in the first place
{
{108.9, 243.3, 0}, // angles (degrees)
{0.996, 0.351, 1.0} // gains
},
// Index 15
// Panasonic CT-36D30B measured by Patchy68k
{
{101.580982936, 232.937328893, 0},
{0.91062624791989, 0.388131199173125, 1.0}
},
// Index 16
// TA8867AN
// From Toshiba CE-20D10, launched in 1994, manufactured in 1995
// I can't confirm, but the middle letter of Toshiba CE/CF CRTs seems to correspond to the launch year--C is 1993, D is 1994, E is 1995, etc.
// Might possibly pair with "EBU-ish" phosphors from a Toshiba patent in 1992.
// The chip has a PAL mode too with different settings.
{
{112, 237, 0},
{0.84, 0.33, 1.0}
},
// Index 17
// TA8801AN
// From Toshiba CF3272B, manufactured in 1993, and probably launched in 1993
// Might possibly pair with "EBU-ish" phosphors from a Toshiba patent in 1992
// The chip has a PAL mode too with different settings.
{
{95, 240, 0},
{0.84, 0.31, 1.0}
},
// Index 18
// TA8867BN
// Unknown what CRT this appears in, but similar chip to TA8867AN
// Might possibly pair with "EBU-ish" phosphors from a Toshiba patent in 1992
// The chip has a PAL mode too with different settings
{
{104, 240, 0},
{0.91, 0.31, 1.0}
},
// Index 19
// TA7698AP
// Datasheet paper has the year 1988
// Appears in JVC TM-9U(CV), also rebranded as the Sensormatic RM409
// I could've sworn that there was a Toshiba CRT from 1988 on crtdatabase that had this chip.
// Might pair with the same phosphors as the CF2005, but don't know.
// Also might pair with the "EBU-ish" phosphors from a 1992 Toshiba patent.
// The chip has a PAL mode too with different settings.
{
{105, 235, 0},
{1.0, 0.38, 1.0}
}
};
What Nestopia and my older presets are missing is the correct primaries, reference white, and default tint/color settings. As I’ve posted a million times by now, I am very confident that the correct primaries are somewhere near this data that Chthon came across, that the reference white is x=0.281, y=0.311 (illuminant 9300k + 27MPCD), and that the default tint and color settings are set to make the red/yellow/green region approximate 1953 primaries with illuminant C (or, for the JP axis mode, illuminant D93 / 9300K + 8MPCD, x=0.283, y=0.298), preferring correct chromaticity over correct luminance, which is very similar to what this ancient paper describes. Although there’s no decisive proof anywhere, I can’t figure out any other way to make this data make any sense, no matter what else I try. Again, we don’t have this kind of data for professional video displays, so this is no help for determining the artists’ intents. (Computer monitors are a completely different story.)
Tritone was discussed earlier. Other Sony TVs have a feature called “Dynamic Color” which can be turned off in the service menu. According to data sheets like the CXA2025AS and CXA1465AS, Dynamic Color also alters the white balance, but the data sheets don’t give any clues as to what else Dynamic Color is doing. My best guess is that it switches between a 9300k+27MPCD decoding based on that ancient paper I mentioned and doing some other decoding.
