| 摘要 |
<p num="1"><br/><br/><br/>A receiver for an enhanced television system in which video data defining a <br/>video stream, enhanced content data defining items of enhanced content, and <br/>trigger messages for triggering the play-out of the enhanced content are <br/>transmitted to receivers over a data network, the receiver comprising an <br/>enhanced content decoder for receiving and playing out enhanced content, and <br/>the enhanced content decoder comprising: a cache for caching enhanced content <br/>data received from the network; and a play-out controller for controlling the <br/>play-out of enhanced content, the play-out controller being arranged to <br/>receive trigger messages over the network and on receiving a trigger message <br/>that indicates an item of enhanced content for which enhanced content data is <br/>stored in the cache and that is to be played out, to play out that item of <br/>enhanced content data at a time indicated by the trigger message, and on <br/>receiving a trigger message that includes a definition of enhanced content, to <br/>play out the enhanced content defined in the trigger message at a time <br/>indicated by the trigger message.<br/>
|
