Putting text on Real media using RealText Markup and SMIL

Making subtitles isn't that difficult. With this tutorial you will be able to put text on any real media video and audio in different languages, maybe in your own native langauge.

Akmal Khan Sapay

.2004.11.04.

RealText Markup

With RealText, you can create timed text presentations that can stream alone or in combination with other media such as audio or video. This makes RealText a handy means for adding text to SMIL presentations. Using RealText, you can add subtitles to a video, for example, or provide closed-captioning.

Understanding RealText

Using any text editor, you can create a RealText clip in a text file that uses the file extension `.rt`. The file includes the text you want to display, as well as the RealText markup that describes how to display and time the text. Like a RealVideo or Flash clip, a RealText clip has a height and width, as well as an intrinsic duration, from a few seconds to several hours. The following are some of the features that RealText provides:

Font, size, and color control
The RealText markup lets you create text in many different fonts, sizes, and colors.

Timing control
RealText timing commands control when each paragraph, sentence, word, or letter appears. You might display a new sentence every few seconds, as in a video subtitle. Or you could make letters appear one at a time as if they were being typed across the screen.

Flowing text
Within a RealText clip, words can scroll up the screen or from side to side. This lets you create a window of smoothly flowing text. You can even make text loop, creating an endlessly flowing marquee.

Positioning commands
With the optional positioning commands, you can control exactly where each word appears within the RealText window.

Structure of a RealText Clip

A RealText clip is a text file that uses the file extension .rt. At the top of the file you write a <window> tag that can include several attributes that set overall parameters, such as the window type, width, height, and duration. The file ends with a </window> tag. Between these tags, you add the text that you want to display in RealOne Player, using RealText tags and attributes to lay out and time the text. The following example is a simple RealText file that displays a new line of text every three seconds:

<window height="250" width="300" duration="15" bgcolor="yellow">
Mary had a little lamb,
<br/><time begin="3"/>little lamb,
<br/><time begin="6"/>little lamb,
<br/><time begin="9"/>Mary had a little lamb
<br/><time begin="12"/>whose fleece was white as snow.
</window>


Combining RealText with SMIL

Now in order to put captions on an real media audio or real media video you have to create a 
SMIL file where you write down the URL of both .rt file and .rm file. See below:

<smil> 
<body>
<par>
<video src="videofile.rm"/>
<textstream src="captionfile.rt"/>
</par>
</body>
</smil>

The <smil> tag tells RealPlayer that this is a SMIL file. The body tag contains the captions.
<par> stands for parallel and indicates that the clips the tag contains will all play at the same time.

Link and play!

I suggest that you open RealPlayer content in the RealPlayer application, rather than embedding it within the Web page. Embedded content is not keyboard accessible and is skipped over by most assistive devices. Unfortunately, you can't link directly to your SMIL file, because the .smil or .smi file extension can also be used by Windows Media Player and Quicktime, and there's no way of telling which program may try to open it. So, instead we are going to link to a RAM file. A RAM file just contains the address of the media clips or SMIL files that we want RealPlayer to open, and it's sure to work, because RAM files will always be opened by RealPlayer only.

RAM files are simple to create. Open a text editor and type the address of the file you want to open on the first line. If it is a file on your web server, it might be something like
http://www.webserver.com/movies/mymovie.rm

If your file uses captions or you want to use a SMIL file, add it like this:
http://www.webserver.com/myfile.smil

If you want to play multiple files in a sequence, place the references to the files each on their own line.

When you're done, save the file with the .ram file extension. Place it on your Web server and create a link to it, just as you would create a link to another Web page. When the user clicks on the link, RealPlayer opens the RAM file, reads the references to the files you want to open, then opens and plays them.

----------------------
Akmal Khan Sapay
Multimedia Editor
Safis Web

----------
See Also:

Windows media captions

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