| 摘要 |
<p>In the DAB system, specific link objects enable a useful way of referring to multimedia objects needed in a multimedia session. The virtual channel field (VChld) included in the link object indicates the transport identifier (Transport Id) which indentifies on which of the logical channels included in the subchannel the refered target object is transferred, and a subchannel identifier (SubChlD). It is difficult, however, for a service producer to utilize links as the subchannel identifiers are created by a DAB operator who sets up the multiplex. The invention shows a method which enables the use of link objects without having exact knowledge where the targeted multimedia object is to be found in the DAB multiplex. The contents of the link objects are defined in such a manner that as the service producer does not know the subchannel identifier (SubChld), this identifier is not used at all in the reference but this target is referred to relatively by using what the receiver is assumed to know already. Therefore in the virtual channel identifier filed (VChld) a channel field is placed where a channel identifier and a component quality description can be given. The packet address and the service identifier, when necessary, can also be indicated.</p> |
