diff --git a/include/defines.php b/include/defines.php
index dedc647..300d49b 100644
--- a/include/defines.php
+++ b/include/defines.php
@@ -1404,37 +1404,61 @@ function and does not affect any other attributes. Before ImageMagick
   </tr>
 
   <tr>
-    <td>uhdr:hdr-color-gamut=<var>value</var></td>
-    <td>Required Specify hdr intent color gamut. Choose from {bt709, display_p3, bt2100}.</td>
+    <td>uhdr:hdr-color-gamut=<var>{bt709|display_p3|bt2100}</var></td>
+    <td>Set input HDR intent color gamut. Used during encoding. Required.</td>
   </tr>
-  
+
   <tr>
-    <td>uhdr:hdr-color-transfer=<var>value</var></td>
-    <td>Required Specify hdr intent color transfer. Choose from {hlg, pq, linear}.</td>
+    <td>uhdr:hdr-color-transfer=<var>{hlg|pq|linear}</var></td>
+    <td>Set input HDR intent color transfer. Used during encoding. Required.</td>
   </tr>
-  
+
   <tr>
-    <td>uhdr:sdr-color-gamut=<var>value</var></td>
-    <td>Required Specify sdr intent color gamut. Choose from {bt709, display_p3, bt2100}.</td>
+    <td>uhdr:sdr-color-gamut=<var>{bt709|display_p3|bt2100}</var></td>
+    <td>Set input SDR intent color gamut. Used during encoding. Required.</td>
   </tr>
-  
+
   <tr>
     <td>uhdr:gainmap-quality=<var>value</var></td>
-    <td>Optional, defaults to 95 Specify gainmap image encoding quality. Choose between [0-100].</td>
+    <td>Set gainmap image encoding quality factor. The valid range is 1 to 100,
+        with 1 indicating lowest image quality or highest compression and 100
+        indicating best quality or least effective compression. Used during
+        encoding. Optional. Default value is 95.</td>
   </tr>
+
   <tr>
     <td>uhdr:gainmap-gamma=<var>value</var></td>
-    <td>Optional, defaults to 1.0 Specify gainmap image encoding gamma. Any positive real number.</td>
+    <td>Set gainmap image encoding gamma. Must be greater than 0.0. Used during
+        encoding. Optional. Default value is 1.0.</td>
   </tr>
-  
+
   <tr>
     <td>uhdr:gainmap-min-content-boost=<var>value</var></td>
-    <td>Value to control how much darker an image can get, when shown on an HDR display, relative to the SDR rendition. Value MUST be in linear scale. *Optional, If not configured, computed internally. Specify min content boost. Any positive real number.</td>
+    <td>Specify the minimum allowed ratio of the linear luminance for the target
+        HDR rendition relative to (divided by) that of the SDR image, at a given
+        pixel. In other words, this specifies how much darker a pixel can get,
+        when shown on an HDR display, relative to the SDR rendition. Must be
+        greater than 0.0. Used during encoding. Optional. If not configured,
+        this is computed dynamically based on the input.</td>
   </tr>
-  
+
   <tr>
     <td>uhdr:gainmap-max-content-boost=<var>value</var></td>
-    <td>Value to control how much brighter an image can get, when shown on an HDR display, relative to the SDR rendition. Value MUST be in linear scale. *Optional, If not configured, computed internally. Specify max content boost. Any positive real number.</td>
+    <td>Specify the maximum allowed ratio of the linear luminance for the target
+        HDR rendition relative to (divided by) that of the SDR image, at a given
+        pixel. In other words, this specifies how much brighter a pixel can get,
+        when shown on an HDR display, relative to the SDR rendition. Must be
+        greater than 0.0. Used during encoding. Optional. If not configured,
+        this is computed dynamically based on the input.</td>
+  </tr>
+
+  <tr>
+    <td>uhdr:output-color-transfer=<var>{hlg|pq|linear|srgb}</var></td>
+    <td>Set the target display transfer characteristics on which the
+        ultrahdr image is rendered. Used during decoding. Required.
+        If <em>srgb</em>, only sdr intent is decoded and sent as output,
+        otherwise, sdr intent and gainmap are decoded, combined into
+        hdr image and sent as output.</td>
   </tr>
   
   <tr>