<its:rules xmlns:its="http://www.w3.org/2005/11/its" xmlns:h="http://www.w3.org/1999/xhtml"  version="2.0">
 <its:externalResourceRefRule selector="//h:video/@src" externalResourceRefPointer="."/>
 <its:externalResourceRefRule selector="//h:video/@poster" externalResourceRefPointer="."/>
</its:rules>