HTML and CSS Reference
In-Depth Information
video.setAttribute('data-playbackRate', setInterval
¬
((function playbackRate () {
video.currentTime += direction;
return playbackRate // allows us to run the function
¬
once and setInterval
})(), 500));
}
}
function playnormal(video) {
if (video.playbackRate != undefined) {
video.playbackRate = 1;
} else { // do it manually
clearInterval(video.getAttribute('data-playbackRate'));
}
}
As you can see from the previous example, if
playbackRate
is supported, you can set positive and negative numbers to
control the direction of playback. In addition to being able to
rewind and fast forward using the
playbackRate
, you can also
use a fraction to play the media back in slow motion using
video.playbackRate = 0.5
, which plays at half the normal rate.
We've talked about the keyboard accessibility of the video
element, but what about transcripts, 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 only meant
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, in a noisy environment
or needing to conserve bandwidth).
The theory of HTML5 multimedia accessibility is excellent. The
original author should make a subtitle file and put it in the con-
tainer Ogg or MP4 file along with the multimedia files, and the
browser will offer a user interface whereby the user can get
those captions or subtitles. Even if the video is “embedded”
on 1,000 different sites (simply by using an external URL as the
source of the video/audio element), those sites get the subtitling
