When a media begins, it sends a begin event. If another media waits for this event, it catches it. To make a media wait to an event, one of its synchronisation attributes (begin or end) should be written as follows:
<!-- if you want tag to start when another tag begins --> <tag begin="id(specifiedId)(begin)" /> <!-- if you want tag to start 3s after another tag begins --> <tag begin="id(specifiedId)(3s)" /> <!-- if you want tag to start when another tag ends --> <tag begin="id(specifiedId)(end)" />
For example:
<body> <par> <img src="cardiff.gif" region="cardiff" id="cf" begin="4s" /> <img src="next.gif" region="next" begin="id(cf)(2s)" /> </par> </body>
will make the next.gif image begin 2s after cardiff.gif begins.