I&#x27;m not sure I&#x27;d qualify TVML as another mark up language.  It looks like an XML standard that adheres to a particular XML schema.  Asking, &quot;Another XML schema?&quot; would sound like a silly question because that&#x27;s the whole point of XML.<p>As for why not HTML? I think there&#x27;s a lot of really good reasons why HTML would be a poor choice.  If you want to restrict Apple TV apps and channels to rely on Apple approved idioms, HTML would be a terrible choice.  Apple isn&#x27;t as interested in creating an open TV browser as much as it&#x27;s interested in creating a unique and positive TV experience.  They can shape that with their own standard.