HTML and CSS Reference
You now know about all the attributes available on the <video>
element. It's time to address the thorny issue of video codecs, which is
even more of a mess than the situation with audio codecs. This has been
one of the more contentious issues in the writing of the HTML5 spec,
not least because video support is seen as being so important.
Containers, codecs, and license issues
The situation with video is even more complex than with audio because
video files need both a visual and an auditory stream, so they need both
video and audio codecs. A format to contain both audio and video also
needs to be defined.
Unlike audio files, where the file extension is linked directly
to the codec being used, with video the file extension is linked
to the container format. To be able to play the video, the browser
needs to support the container format, the video codec, and the
audio codec. In practice, this isn't too much of a factor because
audio codecs without license fees are always paired with video
codecs that don't require a license, and vice versa.
* Google has announced that Chrome will stop supporting
MP4 in a future release.
** IE9 will support WebM if the user downloads an addi-
*** Safari will support anything that can be played by Quick-
Time. Users have to download additional codecs