[css-color-hdr] Reference BT.814 Annex 4 for narrow range PQ and HLG PLUGE, fix #5322

Author: svgeesus

css-color-hdr/Overview.bs

@@ -26,10 +26,16 @@ Abstract: This module defines additions to CSS Color 4 to enable High Dynamic Ra
 			"publisher": "VESA",
 			"href": "https://displayhdr.org/performance-criteria-cts1-1/"
 		},
+		"Rec_BT.814": {
+			"title": "Specifications of PLUGE test signals and alignment procedures for setting of brightness and contrast of displays",
+			"href": "https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.814-4-201807-I!!PDF-E.pdf",
+			"publisher": "ITU",
+			"rawDate": "2018-07"
+		},
 		"Rec_BT.2100": {
 			"title": "ITU-R BT.2100-2 Image parameter values for high dynamic range television for use in production and international programme exchange",
-			"publisher": "ITU",
 			"href": "https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2100-2-201807-I!!PDF-E.pdf",
+			"publisher": "ITU",
 			"rawDate": "2018-07-00"
 		},
 		"Rec_BT.2390": {
@@ -50,7 +56,7 @@ Abstract: This module defines additions to CSS Color 4 to enable High Dynamic Ra
 				"Ciu, Guihua",
 				"Kim, Youn Jin",
 				"Luo, Ming Ronnier"
-				],
+			],
 			"href": "https://www.osapublishing.org/DirectPDFAccess/33630C0F-CFF9-6328-FA6195B4E962F4D7_368272/oe-25-13-15131.pdf?da=1&id=368272&seq=0&mobile=no",
 			"title": "Perceptually uniform color space for image signals including high dynamic range and wide gamut",
 			"publisher": "Optics Express, vol 24 no 13 pp. 15131-15151",
@@ -392,7 +398,13 @@ Predefined color spaces for HDR: {#predefined-HDR}
 		</tr>
 	</table>
 
-	Issue: from BT.2100 p.3 "Note 3d – For PQ in a non-reference viewing environment, or for HLG (in any viewing environment), the black level should be adjusted using the PLUGE test signal and procedure specified in Recommendation ITU-R BT.814."
+	For narrow-range PQ video in a non-reference viewing environment, 
+	or for HLG (in any viewing environment), 
+	the black level should be adjusted 
+	using the PLUGE test signal and procedure 
+	specified in [[Rec_BT.814]] Annex  . 
+	For PQ values in CSS, which uses wide-range, 
+	the black corresponds to code point 0.
 
 	<div class="example">
 		This color represents a blinding white
@@ -505,6 +517,13 @@ Predefined color spaces for HDR: {#predefined-HDR}
 		</tr>
 	</table>
 
+	For narrow-range HLG video (in any viewing environment), 
+	the black level should be adjusted 
+	using the PLUGE test signal and procedure 
+	specified in [[Rec_BT.814]] Annex 4. 
+	For HLG values in CSS, which uses wide-range, 
+	the black corresponds to code point 0.
+
 	Issue: add other examples
 
 	<div class="example">