HTML and CSS Reference
What you need to know about
There are three differ ent
video f ormats in use
across the major brow sers.
We wish everything were as neat and tidy as the
<video> element and its attributes, but as it turns out,
video formats are a bit of a mess on the Web. What's
a video format? Think about it this way: a video file
contains two parts, a video part and an audio part, and
each part is encoded (to reduce size and to allow it to be
played back more efficiently) using a specific encoding
type. That encoding, for the most part, is what no one
can agree on—some browser makers are enamored with
H.264 encodings, others really like VP8, and yet others
like the open source alternative, Theora. And to make
all this even more complicated, the file that holds the video
and audio encoding (which is known as a container ) has
its own format with its own name. So we're really talking
buzzword soup here.
This is a cont ainer…
encoding o f
Anyway, while it might be a big, happy world if all
browser makers agreed on a single format to use across
the Web, well, that just doesn't seem to be in the cards
for a number of technical, political, and philosophical
reasons. But rather than open that debate here, we're
just going to make sure you're reasonably educated on
the topic so you can make your own decisions about
how to support your audience.
Let's take a look at the popular encodings out there;
right now, there are three contenders trying to rule the
Your m ileage may vary by the time
you rea d this topic, as favored
encodin gs tend to chan ge over time.
Ea ch format consi sts of a
co ntainer type (lik e WebM,
MP 4, and Ogg) an d a video and
au dio encoding (lik e VP8 and
The HTML5 specification allows for any video format.
It is the browser implementation that determines what
formats are actually supported.