[css-color-hdr] Consistently used preferred term HDR reference white, not media white

Author: svgeesus

css-color-hdr-1/Overview.bs

@@ -190,14 +190,14 @@ One stop is a doubling of luminance.
 	  } 
 </xmp>
 
-<dfn export>Media white</dfn>,
-also called HDR Reference White,
+<dfn export>HDR reference white</dfn>,
+also called media white,
 is the color of a normal white background, 
 or of white text on a dark background.
 It can be comfortably viewed, over the whole screen.
 
 In <dfn export>Standard Dynamic Range</dfn> (SDR),
-media white is also
+HDR reference white is also
 lightest possible color,
 produced by full-intensity red, green, and blue.
 
@@ -224,8 +224,8 @@ because the darkest color also gets brighter.
 </div>
 
 In <dfn export>High Dynamic Range</dfn> (HDR),
-brighter colors than [=media white=] can be displayed.
-For example, if media white on an HDR display is set to 203 cd/m²
+brighter colors than [=HDR reference white=] can be displayed.
+For example, if HDR reference white on an HDR display is set to 203 cd/m²
 it might be possible to display small highlights at 1000 cd/m².
 Typically, the brightest colors can only be displayed
 on a small part of the display,
@@ -240,7 +240,7 @@ This is because of energy usage and heating considerations.
 </div>
 
 For HDR, using a brighter screen increases the dynamic range,
-while the luminance of media white remains constant.
+while the luminance of HDR reference white remains constant.
 
 <div class="example" id="ex-HDR-PQ-dynamic-range">
 	For example, using the ''rec2100-pq'' colorspace 
@@ -254,18 +254,18 @@ Issue: add a diagram showing SDR and HDR dynamic ranges on a log scale
 
 When [[#Compositing-SDR-HDR]], 
 and for color space conversion,
-the media white for SDR content
+the HDR reference white for SDR content
 should be anchored at <strong>203 cd/m²</strong> [[!Rpt_BT.2408]]
-so that that the media white level 
+so that that the HDR reference white level 
 of the inputs to compositing
-will end up at the media white level 
+will end up at the HDR reference white level 
 of the combined signal.
 
 When displaying HDR (or mixed SDR and HDR) content,
 for displays which are less capable than the reference mastering display,
 and for viewing conditions different to the standard ones,
 a <dfn export>color re-rendering</dfn> step ((OOTF) will be performed.
-This may result in a media white being displayed
+This may result in a HDR reference white being displayed
 at a value lower or higher than 203 cd/m².
 
 <!-- Big Text:  headroom 
@@ -286,41 +286,41 @@ Introducing Headroom {#introducing-headroom}
 	which an HDR display can produce 
 	varies greatly.
 
-	The amount by which peak white is greater than media white
+	The amount by which peak white is greater than HDR reference white
 	is termed the <dfn export>HDR headroom</dfn>,
-	and depends on the level of media white,
+	and depends on the level of HDR reference white,
 	user preference,
 	and viewing conditions.
 
 	It is typically expressed in photographic <strong>stops</strong>.
 	Thus, [=standard dynamic range=] (SDR) 
 	by definition has an [=HDR headroom=] of 0 stops,
-	because the brightest white is media white.
+	because the brightest white is HDR reference white.
 
 <div class="example" id="ex-low-headroom">
 	For example, a low-end HDR display
 	(which <em>just</em> meets the requirements of
 	<a href="https://displayhdr.org/">DisplayHDR 400</a>, 
 	the lowest tier of Vesa Certified DisplayHDR conformance [[DisplayHDR]])
-	might display media white at 
+	might display HDR reference white at 
 	up to 200 cd/m<sup>2</sup>
 	while the peak white is only
 	400 cd/m<sup>2</sup>
-	(at the brightest media white, only one stop of HDR headroom).
+	(at the brightest HDR reference white, only one stop of HDR headroom).
 </div>
 
 <div class="example" id="ex-high-headroom">
 	For example, a high-end HDR display 
 	(which exceeds the requirements of
 	<a href="https://displayhdr.org/">DisplayHDR 1400</a>, 
 	the current highest tier of Vesa Certified DisplayHDR conformance)
-	might display media white at 
+	might display HDR reference white at 
 	up to 400 cd/m<sup>2</sup>
 	while it's peak white is
 	1600 cd/m<sup>2</sup>.
 
 	In dim viewing conditions,
-	with media white set to 100 cd/m<sup>2</sup>,
+	with HDR reference white set to 100 cd/m<sup>2</sup>,
 	this gives four stops (16x) of HDR headroom.
 </div>
 
@@ -389,20 +389,20 @@ The 'dynamic-range-limit' property {#the-dynamic-range-limit-property}
 		<dd>
 			The highest luminance color
 			that is displayed is the same as
-			media white, i.e. the CSS color ''white''.
+			HDR reference white, i.e. the CSS color ''white''.
 		</dd>
 		<dt><dfn>no-limit</dfn>
 		<dd>
 			The highest peak luminance
 			that is displayed is much greater than
-			media white, i.e. the CSS color ''white'';
+			HDR reference white, i.e. the CSS color ''white'';
 			the precise level is not specified.
 		</dd>
 		<dt><dfn>constrained-high</dfn>
 		<dd>
 			The highest peak luminance
 			that is displayed is somewhat greater than
-			media white, i.e. the CSS color ''white'',
+			HDR reference white, i.e. the CSS color ''white'',
 			such that a mix of SDR and HDR content
 			can be comfortably viewed together.
 		</dd>	
@@ -430,7 +430,7 @@ Mixing Dynamic Range Limits: the ''dynamic-range-limit-mix()'' function {#dynami
 --------------------------------------------------------
 
 	This function takes two or more 'dynamic-range-limit' values,
-	converts them internally to a value in stops above media white,
+	converts them internally to a value in stops above HDR reference white,
 	and alters the display to the result of mixing them
 	by the specified amount.
 	The actual calculated result is not exposed.
@@ -716,7 +716,7 @@ Predefined color spaces for HDR: {#predefined-HDR}
 
 	Linear-light RGB signals are converted to PQ encoded as follows.
 	The maximum encodable value (peak, small-area white) in PQ is 10,000 cd/m². 
-	Media white is 203 cd/m² [[!Rpt_BT.2408]].
+	HDR reference white is 203 cd/m² [[!Rpt_BT.2408]].
 
 	<!-- From Froehlich p.42
 		and BT.2100 Table 4 p.4 Reference PQ OETF
@@ -875,7 +875,7 @@ Predefined color spaces for HDR: {#predefined-HDR}
 	regardless of the actual bit depth (10 or 12 bits per component).
 
 	The color with red, green and blue all at 1.0 
-	represents [=media white=] with a luminance of 
+	represents [=HDR reference white=] with a luminance of 
 	203 cd/m².
 
 	<pre class="lang-css">color(rec2100-linear 1 1 1)</pre>
@@ -939,7 +939,7 @@ Predefined color spaces for HDR: {#predefined-HDR}
 	opponent-color axes (similar to a and b in Lab).
 
 	CIE Lab uses a lightness scale with a [0%, 100%] range,
-	relative to media white,
+	relative to HDR reference white,
 	and has been experimentally extended to L=400%.
 	In contrast, the J<sub>z</sub> axis in ''Jzazbz'',
 	which has a [0, 1.0] range,
@@ -1134,14 +1134,14 @@ and not clipped or gamut mapped until
 the final transfer to the device color space.
 
 HDR using the HLG transfer function,
-must map SDR media white
+must map SDR HDR reference white
 to the same luminance as is used
 to display the 75% HLG value. [[!SMPTE-ST-2084]]
 
 For further details, see also tables 3 and 4 in ITU Rpt_BT.2408-0 [[!Rpt_BT.2408]]
 
 HDR using the PQ transfer function,
-should map SDR media white
+should map SDR HDR reference white
 to 203 cd/m², the same luminance as is used
 to display the 58% PQ value. [[!SMPTE-ST-2084]].
 
@@ -1235,7 +1235,7 @@ Serializing values of the ''color()'' function</h3>
 
 The BT.2020 and BT.2100 color spaces 
 use the same RGB primaries and white point,
-and both place media white at a component value of 1.0.
+and both place HDR reference white at a component value of 1.0.
 
 <pre class="include-code lang-javascript">
 	path: rec2100-linear.js