Splicing compressed packetized digital video streams

An apparatus for splicing a secondary packetized data stream with a primary packetized data, comprising:

• means for providing a start signal indicating a time to initiate said splicing;
• means for determining a pre-splicing packet of said primary stream according to said start signal;
• means for providing an output stream where a first packet of said secondary stream is positioned to follow said pre-splicing packet;
• means for determining a post-splicing packet of said primary stream which follows said pre-splicing packet;
• means for discarding data of said pre-splicing packet which is associated with said post-splicing packet;
• and
• means for adding an amount of stuffing data to said pre-splicing packet according to the amount of data discarded.

A decoder for decoding a transport data stream which comprises a secondary packetized data stream which is spliced with a primary packetized data stream, wherein a first packet of said secondary stream is positioned to follow a pre-splicing packet of said primary stream, said decoder comprising:

• a buffer for storing said transport data;
• and
• a processor coupled to receive data from said buffer for processing said transport data;
• wherein:
• a number L of null packets are provided between said pre-splicing packet and said first packet to prevent overflow of said buffer;
• and
• said number L is determined according to respective data rates of said primary and secondary streams and according to a decoding delay time of said decoder.

A method for splicing a secondary packetized data stream with a primary packetized data stream, comprising the steps of:

• providing a start signal indicating a time to initiate said splicing;
• determining a pre-splicing packet of said primary stream according to said start signal;
• providing an output stream where a first packet of said secondary stream is positioned to follow said pre-splicing packet;
• determining a post-splicing packet of said primary stream which follows said pre-splicing packet;
• positioning said post-splicing packet to follow a last packet of said secondary stream in said output stream;
• discarding data of said post-splicing packet which is associated with a packet of said primary stream which precedes said post-splicing packet;
• and
• adding an amount of stuffing data to said post-splicing packet according to the amount of data discarded.

An apparatus for splicing a secondary packetized data stream with a primary packetized data stream, comprising:

• means for providing a start signal indicating a time to initiate said splicing;
• means for determining a pre-splicing packet of said primary stream according to said start signal;
• means for providing an output stream where a first packet of said secondary stream is positioned to follow said pre-splicing packet;
• means for determining a post-splicing packet of said primary stream which follows said pre-splicing packet;
• means for positioning said post-splicing packet to follow a last packet of said secondary stream in said output stream;
• means for discarding data of said post-splicing packet that is associated with a packet of said primary stream which precedes said post-splicing packet;
• and
• means for adding an amount of stuffing data to said post-splicing packet according to the amount of data discarded.