| 摘要 |
In an MPEG-2 decoding system, a transport decoder decodes a transport packet corresponding to a Program Identification (PID) from an input transport stream, and retrieves a Program Association Table/Program Map Table PAT/PMT) from the stream when it is requested to retrieve Program Specific lnformation (PSI). A pre-decoder checks PSI stored in a PSI memory in response to a request to change to a desired channnel, reads PIDs of transport packets for a Packetized Elementary Stream (PES) of a program corresponding to the desired channel from the PSI memory to provide it to the transport decoder, receives the PAT/PMT and updates the contents of the memory using the PAT/PMT. After decoding, PSI previously extracted therefrom is stored in the memory. PIDs of transport packets for the PES of desired program are obtained referring to the stored PSI, and transport packets having the PIDs are retrieved and decoded. |
