Packet filtering

A method of filtering a packet data stream as transmitted in a digital audio visual transmission system and received by a receiver/decoder, comprising:

• filtering a received first transport packet data containing data in the form of packet stream data by a digital filter according to the characteristics of the transport packet header;
• passing filtered data directly to a memory element within the receiver/decoder for storage in the form of a complete transport packet including the packet header and payload;
• filtering, in parallel to said first transport packet data, a second transport packet data containing data in the form of packet stream data according to the value of the packet ID;
• and
• dividing out the payload from a received packet, the payload being sent in real time to at least one corresponding processor element,
• wherein data contained within the payload of a transport packet is itself organized in the form of secondary packets of data each with a header and a payload and the secondary data packets have a variable packet length.

A receiver/decoder for a digital audiovisual transmission system, comprising:

• a first digital filter, for filtering first transport packet data received by the receiver/decoder and containing data in the form of packet stream data according to the characteristics of the transport packet header, and passing selected filtered data directly to a memory element for storage in the form of a complete transport packet including the packet header and payload;
• and
• a second digital filter, for filtering, in parallel to said first transport packet data, second transport packet data received by the receiver/decoder and containing data in the form of packet stream data according to the value of the packet ID, to divide out the payload from a received packet, and passing the payload in real time to at least one corresponding processor element,
• wherein the first digital filter is arranged to pass selected data from the payload of a transport packet to a third filter.