Source

{{Title| ''' element was first introduced in HTML5 and Gecko 1.9.1. It is used to specify multiple media resources for  and   elements. Currently, Gecko picks the first  element that has an exact MIME type of   or.

Attributes
HTML examples:

element.

Multiple  elements can be used in order to provide video/audio encoded in different formats for compatibility with different browsers.

element.

Here, it specifies that the video uses the Dirac and Speex codecs. If the browser supports Ogg, but not the specified codecs, the video will not load.