2002.02_Maximising Multimedia on the Web with Plug-Ins.pdf

FEATURE

BROWSER

Maximising multimedia on the web

PLUG-INS

Static, fixed, web

pages are dead: it’s

now a world of

streamed audio and

video. So what does

a Linux user need to

make use of all this?

Colin Murphy

explains

For the main part they’re informative, always quick

to load even if resources are in short supply, and

they helped the Internet becomes what it is today. But

not for much longer, or so it seems – you can’t go

near a site these days without being blinded by

graphics, both fixed and moving, being shoved at you.

The technology is there to send out this

information so out it goes, whether you want to

receive it or not. This is all well and good for

advertisers – the eye and ear-catching nature of these

pyrotechnics are ideal for those intent on making you

look at their wares just long enough for the name

and product to slip into your sub-conscious – but this

just made me all the keener to avoid it.

However, now, much more than ever, the

information that you actually want is going to be

found on Web sites that rely on you working your

way through these flashy sites. Increasingly, the very

thing you’re looking for may be noisy or moving,

which means that you need to make sure that your

Web browser can deal with these forms of data, with

a little help from plug-ins .

Plug-ins

There is a wide range of different plug-ins in use on

the Internet today, but not all of them are available

for Linux straight off. Much of the information out

there in Internet land is provided in a proprietary

format, which usually means that you need to pay

someone to make full use of the data held in that

format by buying a plug-in.

For example, you can listen to radio via the

Internet: broadcasters provide their output as a

stream of data, which gets pushed out over the

network. For most Internet radio broadcasts, this

information is sent in the proprietary Real Audio

format. To be able to listen to the radio in this format

you need to have access to a Real Audio plug-in.

Luckily enough, there is a Real Audio plug-in Linux

Java as a plug-in

Plug-ins Tools to enhance

and extend the operation

and functionality of an

application. With Internet

browsers, this enables you

to use types of data not

originally associated with

Web pages. It usually frees

you from the chore of

having to download a

chunk of data, only to

then have to run it in

some external application.

Java is a platform independent object-oriented

programming language, used for writing applets that are

downloaded from the Internet by a client and run on the

client’s machine – usually by the browser.

The data that you download is run by the Java client,

but inside the browser. Take a look at

http://www.magenet.com/~julie/java/rubik to see some

Java in action (see Figure 3).

You might find that you need to install Java yourself.

There is an Open Source version of Java called Kaffe,

which is supplied with most of the Linux distributions.

However, most people seem to prefer to use the version

provided by Blackdown Java.

Unless you plan on developing Java applications you

will only need the Java Runtime Environment, or jre, a

copy of which you’ll find on the coverdisc.

Figure 3: A Java-enabled

Konqueror

LINUX MAGAZINE

Issue 17 • 2001

I ’m personally quite happy with static Web pages.

FEATURE

Users can use, which is maintained by the Linux

community. However, because of its proprietary

nature, you will only get the Real Audio plug-in

included in a Linux Distribution if you get one of the

more expensive boxed sets. This means it won’t be

set up by default if you’re using a distribution you

got from CheapBytes, for instance. You will have to

go and download it yourself, which is not ideal.

DjVu – a world without paper?

This new world of information isn’t only video and audio-based, according to the

people at DjVu, 90 per cent of world information is on paper. Bringing this

wealth of information to the Internet has had its problems. The high resolution

needed to read a scanned-in document means that files sizes grow to beyond

manageable proportions. The DjVu image compression technology developed at

the AT&T Labs offers a solution to this problem. With DjVu, it seems that a 31Mb

TIFF file can be reduced to just 70Kb. There’s a browser plug-in for Linux –

DjVuLibre – that enables you to view this information and manipulate it all in

your browser.

When viewing a DjVu document in an enabled browser you are given a range

of facilities to help you view it better. In Figure 1, an area of text has been

highlighted, at the release of the mouse key the view from Figure 2 can been

seen. The image isn’t being reloaded, rather the browser is redisplaying it to our

requirements. This plug-in is compatible with all of the browsers you’re likely to

use: Netscape, Mozilla, Konqueror and more.

Ogg Vorbis

Luckily, work is in hand to produce non-proprietary

audio streams, thanks to the developers of Ogg

Vorbis. The challenge is now to get the broadcasters

to use and accept this alternative streaming format.

The BBC is currently running Ogg Vorbis trials, so

with a little campaigning and persuasion, the dream

of all of the BBC output being broadcast in a stream

we can all appreciate might just become a reality.

Take a look at http://support.bbc.co.uk/ogg and

maybe even email oggfeedback@bbc.co.uk .

The browser needs to be configured to make use

of a plug-in, and this will often happen automatically

during the installation. The Ogg Vorbis plug-in is

included with most distributions these days, and so

is likely to be configured for you. The Real Audio

plug-in will configure itself automatically for

Netscape during its installation, but you will need to

take manual steps to get it to work with other

browsers like Mozilla or Opera. Luckily these

browsers have details in their documentation

describing how this is done.

Figure 1: Some text in

DjVu format, with a

region highlighted for

enlargement

xmms – the sound of a planet

One Linux program that uses plug-ins is xmms, the

multimedia player that comes with most installations.

You will most likely have called upon the services of

xmms should you have selected any of the Ogg

Vorbis links on the BBC Web site.

If your speaker system includes a sub-woofer, you

can put it through its paces with the “tone” plug-in.

With xmms running press Ctrl+L to open up the

Location to play box and enter the location tone://30 .

This calls upon the Sine Wave generator plug-in and

produces a 30Hz tone. Wait and see how long it takes

for the neighbours to come and complain at full

volume. The test is to see how far they come from.

Figure 2: The previously

selected text enlarged.

Also note the control

buttons that appear

from an auto-hiding

What’s not available?

There are lots of different plug-ins, some are more

use than others. But the only plug-in that we really

miss out on is that for QuickTime, though even here

there is a solution. A product call Crossover will

enable you to use many of the Windows plug-ins,

including QuickTime.

asp – Shockwave and Flash

Macromedia Flash files (they have a suffix .spl) are

designed to deliver low-bandwidth animation and

presentations. There is a browser plug-in for Linux,

but this time it is only compatible with Netscape and

Opera – there’s no support for Konqueror.

You may also come across Shockwave files (with a

suffix .swf), which luckily enough are dealt with by

the same plug-in. It can be a bit confusing as the

Macromedia site offers downloads for both formats,

but then offers you the same file.

Info

xmms http://www.xmms.org

Flash and Shockwave http://www.macromedia.com/shockwave/download/

alternates

DjVu http://djvu.sourceforge.net

Blackdown JDK Linux http://www.blackdown.org

Crossover

http://www.codeweavers.com/products/crossover

Issue 17 • 2001

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