Data is available for the current playback position, but not enough to actually play more than one frame.
Enough data is available—and the download rate is high enough—that the media can be played through to the end without interruption.
Data for the current playback position as well as for at least a little bit of time into the future is available (in other words, at least two frames of video, for example).
Enough of the media resource has been retrieved that the metadata attributes are initialized. Seeking will no longer raise an exception.
No information is available about the media resource.
There is no data yet. The readyState is also HAVE_NOTHING.