Anne van Kesteren

SMIL Namespace Documentation

There is Synchronized Multimedia Integration Language 1.0. It has no namespace. Probably because it was from 1998 and Namespaces in XML became a recommendation in 1999. According to some text in a SMIL 2.0 module the namespace might have become: This is not entirely clear given that normally the pointer to the specification is very different from the pointer to the namespace and it violates the namespace policy from the W3C. Of course, SMIL 1.0 predates that policy so that might be the explanation.

After SMIL 1.0 came SMIL 2.0 not to be confused with the document that is currently hosted at or It is located at a place quite hard to find. Now when you read 2.3.3 Identifiers for SMIL 2.0 Modules and Features you might think you are looking at feature identifiers but you are actually looking at a long list of namespaces. You can find partial proof for that in bullet point nine in Conforming SMIL 2.0 Documents.

Synchronized Multimedia Integration Language 2.1 does not change that much with regard to that. Previously I claimed that SMIL 2.1 had six different namespaces elements could be in. I was wrong. There are 48 different namespaces SMIL 2.1 elements and attributes can be in. (Given that I counted correctly.) Including SMIL 1.0 and SMIL 2.0 there are 111 different namespaces to choose from. I think I can now safely answer my question with regard to whether or not SMIL is a mess. Leaving alone that it does not integrate well with the DOM et cetera. Given that this is some documentation, here is the full list:

Ten namespaces more than HTML element names in HTML 2.0, 3.2, 4.01 and XHTML 1.1 combined.