| 摘要 |
The Logical Channel Table (LCT), utilizing simple conventional channels or Composite Channels, provides mapping between a Logical Channel Number (LCN) representing a service and the transport stream (TSID) / program number (PN) on which the service can be found. The LCT entry contains a Composite Channel Indicator (CCI), which when set to '1', indicates that the selected channel is a composite channel thereby indicating the home channel of the Composite Channel. The LCT provides the Composite Channel Table (CCT) to the decoder (10) so that the tuner (12) can be returned to the actual program designated in the CCT for current viewing. Each entry in the CCT associates a Composite Channel Number (CCN) with a LCN and represents the "present" definition for the composite channel. As time progresses, the CCN is used as a "pointer" to the LCN which is the currently active service for the composite channel. These tables work with conventional MPEG-2 service definitions to decode multiservice transport streams. |
