Change AV1 and VP9 quantizer range from 0-63 to 0-255

This change fixes: #904

Author: Djuffin

av1_codec_registration.src.html

@@ -108,7 +108,7 @@
   <dt><dfn dict-member for=VideoEncoderEncodeOptionsForAv1>quantizer</dfn></dt>
   <dd>
     Sets per-frame quantizer value.
-    In [[AV1]] the quantizer threshold can be varied from 0 to 63
+    In [[AV1]] the quantizer index can be varied from 0 to 255
   </dd>
 </dl>
 

vp9_codec_registration.src.html

@@ -106,7 +106,7 @@
   <dt><dfn dict-member for=VideoEncoderEncodeOptionsForVp9>quantizer</dfn></dt>
   <dd>
     Sets per-frame quantizer value.
-    In [[VP9]] the quantizer threshold can be varied from 0 to 63
+    In [[VP9]] the quantizer index can be varied from 0 to 255
   </dd>
 </dl>