--- a/ttml10/spec/rnc/ttaf1-dfxp-datatypes.rnc	Thu Jun 28 00:23:56 2012 -0600
+++ b/ttml10/spec/rnc/ttaf1-dfxp-datatypes.rnc	Thu Jun 28 07:53:06 2012 -0600
@@ -72,7 +72,7 @@
   "bold"
 
 TTAF.FrameRate.datatype =
-  xsd:nonNegativeInteger
+  xsd:positiveInteger
 
 TTAF.FrameRateMultiplier.datatype =
   xsd:string { pattern = "\p{Nd}+\s+\p{Nd}+" }

--- a/ttml10/spec/xsd/ttaf1-dfxp-datatypes.xsd	Thu Jun 28 00:23:56 2012 -0600
+++ b/ttml10/spec/xsd/ttaf1-dfxp-datatypes.xsd	Thu Jun 28 07:53:06 2012 -0600
@@ -102,7 +102,7 @@
     </xs:restriction>
   </xs:simpleType>
   <xs:simpleType name="frameRate">
-    <xs:restriction base="xs:nonNegativeInteger"/>
+    <xs:restriction base="xs:positiveInteger"/>
   </xs:simpleType>
   <xs:simpleType name="frameRateMultiplier">
     <xs:annotation>