I am looking for the luminance values (Y) for the primaries and secondaries for SD or Rec601. I have the xy values:

Rec. 601 (SMPTE C) for 480i, 480p

White (D65) = 0.3127, 0.3290
Red = 0.630, 0.340
Green = 0.310, 0.595
Blue = 0.155, 0.070
Yellow = 0.421, 0.507
Cyan = 0.231, 0.326
Magenta = 0.314, 0.161

but I am looking for the Y or Luminance values. I have looked on in some of Poynton's papers but they are a bit over my head. Tom Huffman has created a great guide to setting up color using HCFR here (http://www.avsforum.com/avs-vb/showthread.php?t=852536). I was interested in doing it for SD. Are the Y values the same for HD and SD.

SMPTE-C Y
White 1.00
Red 0.212
Green 0.701
Blue 0.087
Cyan 0.788
Yellow 0.914
Magenta 0.299

Answered.

Thanks again Tom.

angryht

It is important to understand that REC601 is for decoding assuming an NTSC display - which never existed as it had a significantly wider impossible gamut. SMPTE-C has been settled on as the convention for these display. If you are probing the encoder/decoder voltages/numbers you would want to follow REC601 numbers - if you are measuring the display you want SMPTE-C numbers. So be careful with terminology or you will use the wrong numbers - because the video chain is NOT in sync with itself by standard design! While SD could have changed encoding/decoding from NTSC to one based on a SMPTE-C - too much video legacy to change.

Only with REC709 is the encoder/decoder display assumption indeed REC709. SMPTE-C display is not that different from a REC709 display - but REC601 encode/decode is significantly different from REC709 encode/decode. It is this legacy that causes SD/HD translation issues to be very visible. If you want to measure the display you will need to make sure you eliminate such coding/decoding errors so that you have a reference RGB being displayed. You could end up trying to fix display errors that are really just an issue of not having a reference RGB in the PJ! This is not as easy as it sounds - just send in a reference RGB signal - because some PJ run the RGB data thru the video controls and can muck up the RGB!

Hi,
I'm looking for xyY for EBU and REC-709. Thanks.
I have only this:

EBU Gamut:
Red : x:0.6400, y:0.3300
Green : x:0.2900, y:0.6000
Blue : x:0.1500, y:0.0600
White point : x:0.3127, y:0.3290

HDTV Gamut (REC-709):
Red : x:0.6400, y:0.3300, Y:0.015
Green : x:0.3000, y:0.6000, Y:0.022
Blue : x:0.1500, y:0.0600, Y:0.018
White point : x:0.3127, y:0.3290

SMPTE-C Gamut:
Red : x:0.635, y:0.340, Y:0.212
Green : x:0.305, y:0.595, Y:0.701
Blue : x:0.155, y:0.070, Y:0.087
Cyan : x:0.231, y:0.326, Y:0.788
Yellow : x:0.421, y:0.507, Y:0.914
Magenta : x:0.314, y:0.161, Y:0.299
White point : x:0.3127, y:0.3290, Y:1.00

These Rec. 709 Y values are not correct.

The correct values are
Rec. 709
R: 0.2126
G: 0.7152
B: 0.0722

EBU
R: 0.2022
G: 0.7067
B: 0.7130 [edit, typo 0.0713]

The secondaries are just the sum of the contributing primaries.

Hi,
I'm looking for xyY for EBU and REC-709. Thanks.
I have only this:

EBU Gamut:
Red : x:0.6400, y:0.3300
Green : x:0.2900, y:0.6000
Blue : x:0.1500, y:0.0600
White point : x:0.3127, y:0.3290

HDTV Gamut (REC-709):
Red : x:0.6400, y:0.3300, Y:0.015
Green : x:0.3000, y:0.6000, Y:0.022
Blue : x:0.1500, y:0.0600, Y:0.018
White point : x:0.3127, y:0.3290

SMPTE-C Gamut:
Red : x:0.635, y:0.340, Y:0.212
Green : x:0.305, y:0.595, Y:0.701
Blue : x:0.155, y:0.070, Y:0.087
Cyan : x:0.231, y:0.326, Y:0.788
Yellow : x:0.421, y:0.507, Y:0.914
Magenta : x:0.314, y:0.161, Y:0.299
White point : x:0.3127, y:0.3290, Y:1.00

I know you already know it, but to avoid confusion, the correct Blue value for EBU is 0.071... ;)


EBU
...
B: 0.7130

The secondaries are just the sum of the contributing primaries.

I know you already know it, but to avoid confusion, the correct Blue value for EBU is 0.071... ;)Sorry, typo. 0.0713.

I have this coordinates for x in SMPTE-C :
Red : x:0.6350
Green : x:0.3050

It is not exactly the same than here :
http://www.avsforum.com/avs-vb/showthread.php?t=852536

AVS :
R--- x:0.6300
G--- x:0.3100

What is the correct x coordinates ?

I have this coordinates for x in SMPTE-C :
Red : x:0.6350
Green : x:0.3050

It is not exactly the same than here :
http://www.avsforum.com/avs-vb/showthread.php?t=852536

AVS :
R--- x:0.6300
G--- x:0.3100

What is the correct x coordinates ?

Hopefully Tom will clarify. I would think that the numbers in his guide are correct. This thread was started just when he was developing it so I think he has been keeping the guide up to date more so than this thread. Also, the numbers in his guide match his recent article in Widescreen Review which I would guess was peer reviewed by the staff. I would go with the 0.630 and 0.310.

Hopefully Tom will clarify. I would think that the numbers in his guide are correct. This thread was started just when he was developing it so I think he has been keeping the guide up to date more so than this thread. Also, the numbers in his guide match his recent article in Widescreen Review which I would guess was peer reviewed by the staff. I would go with the 0.630 and 0.310.The numbers in the tutorial are correct.

Thanks, Tom.