Commands

Command tags add functionality and interactivity to a SMIL presentation. For example, you can use them to launch URLs in a browser or RealPlayer, or to issue RealPlayer commands such as Pause and Play.

The syntax of command tags is very similar to HTML, in that it uses standard <a href ...> and </a> tags, and usually specifies a target where the action specified will occur.

Opening a URL in RealPlayer

The following RealText tag makes the text enclosed between <a href...> and </a> a hyperlink that opens in RealPlayer:

<a href="URL" target="_player">...</a>

The specified URL should begin with a protocol designation such as http:// or rtsp://. The URL can use any protocol RealPlayer or the user's Web browser supports. The optional target="_player" attribute launches the new stream in the current RealPlayer window. If you do not use the target attribute or you specify target="_browser", the linked URL opens in a Web browser window.

The following example launches a new SMIL Presentation in RealPlayer:

<a href=
"rtsp://realserver.bu.edu:554/ramgen/a/v/av/nis/training/smil2/video2.smil target="_player">Play Next</a>

Opening a URL in a Web Browser

You can create hyperlinks to web pages in RealText. The hyperlink syntax is identical to HTML. For example:

<a href="http://www.bu.edu/webcentral/">Visit WebCentral</a> to learn more about this topic.

You can also create e-mail hyperlinks using the mailto: syntax just as in HTML.

RealPlayer Commands

RealPlayer commands include functions such as stopping and starting the player, or moving to a specific point in the playback timeline. All command tags contain the following basic elements, with modifications for each specific type of command:

<a href="command:<some command>" target="_player">...</a>

Note that commands are case-sensitive and must be enclosed in double quotes. The target="_player" attribute is required. The following sections describe the available commands for RealPlayer:

Command Syntax

Seek <a href="command:seek(time)" target="_player">
Pause <a href="command:pause()" target="_player">
Play/Resume <a href="command:play()" target="_player">