Welcome!

Java Authors: Pat Romanski, Liz McMillan, Elizabeth White, Jason Bloomberg, Yeshim Deniz

Related Topics: AJAX & REA, Web 2.0

AJAX & REA: Blog Post

HTML5: Media in a Flash...Without Flash!

Part Two of a 4-part primer to HTML5 development

Welcome to part two of the four part primer to HTML5 development. In this article, I will showcase some of the additions to the HTML5 tag library that we can leverage to make media-rich websites and web applications in the blink of an eye without Flash or other 3rd-party code.

HTML5-Compatible Web-Browsers
HTML5-Compatible WebBrowsers

The <AUDIO> tag:

The first tag we will look at is the <AUDIO> tag.  This new tag allows us to embed audio content in a variety of formats that the browsers will understand.  As of now the browser file format support is somewhat spotty, so it’s worth checking the chart at w3c.org and enabling multiple file formats inside the audio tag.

Lets do a quick example of the <audio> tag:


<audio controls="controls">
<source src="song.ogg" type="audio/ogg" />
<source src="song.mp3" type="audio/mpeg" />
Your browser does not support the audio element.
</audio>

Before we had to embed a player application, then have some javascript load the object into the player, and finally, the player would play the music for us.  With HTML5 compatible browsers, we just load a new audio object with controls.

The control GUI isn’t standardized, so you may see some issues in formatting when you view with diffrent browsers, but on the whole this process is much easier.

If you wanted to have the audio play automatically, loop, or do something when it is buffering you can do that quite easily.


<audio src=”song.ogg” autoplay loop>Your browser does not support audio tags</audio>

You’ll note that there are no = signs or quotes — we don’t need them anymore! HTML5 eliminates the need for boolean attributes to have = or “”‘s. Simply put the name of the desired boolean property and it will be interpreted by the browser as being set to true. We’ll discuss this syntax change at length in the next article.

Below is the table of currently supported audio formats and the browser support for each:

Format IE 8 Firefox 3.5 Opera 10.5 Chrome 3.0 Safari 3.0
Ogg Vorbis No Yes Yes Yes No
MP3 No No No Yes Yes
Wav No Yes Yes No Yes

According to this chart from W3C (link here, we will need at least two file formats of our audio file in order to cover all major browsers.  For the example I chose Ogg and Wav formats.


<audio loop autoplay>Your browser does not support audio tags.
<source src="song.ogg" type="audio/ogg" />

<source src="song.wav" type="audio/mpeg" />

</audio>

This will allow the browsers to select the correct file type it needs with only two additional lines of code!

The <VIDEO> tag:


<video src="movie.ogg" controls="controls">
your browser does not support the video tag
</video>

We can see that the formatting is exactly the same as the audio tag.  Like audio, we can also define multiple file sources in order to supply the correct format.  All major web browsers support Ogg video and/or MP4.


<source src="movie.ogg" type="video/ogg" />
<source src="movie.mp4" type="video/mp4" />

You’ll probably need to do alot more than just display some video with some controls, though.  This is where the new HTML5 events come in.  Try a few of the selections below with some javascript at the w3c website here http://www.w3schools.com/html5/tryit.asp?filename=tryhtml5_video_simple

oncanplaythrough — play the element as soon as it is buffered.
oncanplay — play when able, even if it might have to stop for buffering.
preload — buffer the element and wait for play.
autoplay — Play as soon as page loads, don’t wait for buffering
onend — do something when the element is done (like play the next video in a set)
onemptied — do something if the buffer is used up and no more buffer remains (like from disconnections)
onerror — pretty self-explanitory.  Do something if any errors in playing the element are encountered

A full list of HTML5 events can be viewed here: http://www.w3schools.com/html5/html5_ref_eventattributes.asp

The <object> Tag:

The <object> tag takes over the loading of applications into the web browser from the <applet> tag.  It makes it easier for both programmers and machines alike to read HTML markup and determine the values and settings being passed into the loaded application.  Take this example of an embedded object:


<object classid="xxxxxxxx-xxxxxx" id="example">
<param name="code" value="test.class" />
<param name="test2" value="testing" />
<param name="fname" value="Alan" />
<param name="lname" value="Jenner" />
</object>

<object> tags have multiple ways to declare the source of the target application or plugin: URLs and windows registry items with the “classid” option, or three other src-related attributes. It doesn’t matter which you use as long as you follow this style:


<param name=”[code/src/data]” value=”[URL]”>

You can define code, src, data, or any of the other parameters in the <object> tag itself or within <param> elements.

What's with the weird tags?

You may be asking at this point why the <object> tag is structured this way.  It’s structured with these extra tags to make it easier for machines to read the code in websites, something that will be needed for the semantic web, a revolution in how the web works similar to web 2.0.

Tim Berners-Lee (the creator of the World Wide Web) defines the semantic web thusly:

I have a dream for the Web [in which computers] become capable of analyzing all the data on the Web – the content, links, and transactions between people and computers. A ‘Semantic Web’, which should make this possible, has yet to emerge, but when it does, the day-to-day mechanisms of trade, bureaucracy and our daily lives will be handled by machines talking to machines. The ‘intelligent agents’ people have touted for ages will finally materialize.

In the next article, I will go into the semantic web in depth and show examples of the syntactical changes from HTML4 to HTML5 that will facilitate the development of the semantic web.

Read the original blog entry...

More Stories By Bryan Halfpap

Bryan Halfpap is an Engineering Intern II at ARINC.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.