HTML and CSS Reference
In-Depth Information
Full-screen video
For some time, the spec prohibited full-screen video, but it's
obviously a useful feature so WebKit did its own proprietary
thing with
WebkitEnterFullscreen()
;. WebKit implemented its API
in a way that could only be triggered by the user initiating the
action; that is, like pop-up windows, they can't be created unless
the user performs an action like a click. The only alternative to
this bespoke solution by WebKit would be to stretch the video
to the browser window size. Since some browsers have a full-
screen view, it's possible to watch your favourite video of Bruce
doing a Turkish belly dance in full screen, but it would require
the user to jump through a number of hoops—something we'd
all like to avoid.
In May 2011, WebKit announced it would implement Mozilla's full-
screen API
(
https://wiki.mozilla.org/Gecko:FullScreenAPI
)
. This API
allows any element to go full-screen (not only
<video>
)—you might
want full-screen
<canvas>
games or video widgets embedded in
a page via an
<iframe>
. Scripts can also opt in to having alphanu-
meric keyboard input enabled during full-screen view, which means
that you could create your super spiffing platform game using the
<canvas>
API and it could run full-screen with full keyboard support.
As Opera likes this approach, too, we should see something
approaching interoperability. Until then, we can continue to fake
full-screen by going full-window by setting the video's dimen-
sions to equal the window size.
We've talked about the keyboard accessibility of the video ele-
ment, but what about transcripts and captions for multimedia?
After all, there is no
alt
attribute for video or audio as there is
for
<img>
. The fallback content between the tags is meant only
for browsers that can't cope with native video, not for people
whose browsers can display the media but can't see or hear it
due to disability or situation (for example, being in a noisy envi-
ronment or needing to conserve bandwidth).
There are two methods of attaching synchronized text alter-
natives (captions, subtitles, and so on) to multimedia, called
in-band and out-of-band. In-band means that the text file is
included in the multimedia container; an MP4 file, for example,
is actually a container for H.264 video and AAC audio, and can
