Packet filtering

• US 20030007568A1
• Filed: 07/26/2002
• Published: 01/09/2003
• Est. Priority Date: 11/17/1997
• Status: Active Grant

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Declerck, Christophe, Hamery, Dominique, Tranchard, Lionel
• Granted Patent: US 7,116,719 B2
• Time in Patent Office: Days
• US Class Current: 375/240.26
• CPC Class Codes: H04N 21/4181 for conditional access
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4385 Multiplex stream processing, e.g. multiplex stream decrypting
• CPC Class Codes: H04N 21/4854 for modifying image parameters, e.g. image brightness, contrast

Abstract

A method of filtering a packet data stream as transmitted in a digital audiovisual transmission system characterized in that transport packet data is filtered at a first stage by a digital filter (42) according to the characteristics of the transport packet header, selected filtered data being then passed directly to a memory element (44) within the receiver/decoder. In a second aspect, the method comprises filtering a packet data stream characterized in that transport packet data is filtered at a first stage by a first digital filter (42) according to the characteristics of the transport packet header, selected filtered data from the payload corresponding to a continuous flux of data then being passed to a second digital filter (45) for a second stage of filtering.

Claims

1. A method of filtering a packet data stream as transmitted in an digital audiovisual transmission system and received by a receiver/decoder characterised in that transport packet data is filtered at a first stage by a first digital filter according to the characteristics of the transport packet header, selected filtered data being passed directly to a memory element within the receiver/decoder.

2. A method of filtering a packet data stream as claimed in claim 1 in which the transport packet data is filtered at least according to the value of a packet ID within the transport packet header.

3. A method of filtering a packet data stream as claimed in claim 1 or 2 in which the transport packet data is filtered according to other bit values within the transport packet header in addition to the value of the packet ID.

4. A method of filtering a packet data stream as claimed in any preceding claim in which a complete transport packet including the packet header and payload is passed to and stored in the memory element.

5. A method of filtering a packet data stream as claimed in any preceding claim in which the transport packet data is transmitted in packets of fixed size, the memory element having the same size as the fixed packet size.

6. A method of filtering a packet data stream as claimed in any preceding claim in which data contained within the payload of a transport packet is itself organised in the form of secondary packets of data each with a header and a payload.

7. A method of filtering a packet data stream as claimed in claim 6 in which the secondary data packets have a variable packet length.

8. A method of filtering a packet data stream as claimed in any preceding claim in which the data contained in the payloads of the transport packet data stream corresponds to a continuous flux of data.

9. A method of filtering a packet data stream as claimed in any preceding claim in which the transmitted data is organised in an MPEG format.

10. A method of filtering a packet data stream as claimed in claim 9 in which the data contained in the payload of an MPEG transport packet is organised in the form of a packetised elementary stream.

11. A method of filtering a packet data stream as claimed in any preceding claim in which the digital filter may also pass selected data from the payload of a transport packet to a processor for execution.

12. A method of filtering a packet data stream as claimed in any preceding claim in which the digital filter may also pass selected data from the payload of a transport packet to a second digital filter.

13. A method of filtering a packet data stream as claimed in claim 12 in which data contained in the payload of transport packets is organised in the form of secondary data packets, the second digital filter acting to filter the secondary packets based on the value of one or more elements of the header of the secondary packets of data.

14. A method of filtering a packet data stream as claimed in claim 13 in which data filtered by the second digital filter is then passed to an associated memory element for storage and/or to a processor for execution, depending on the results of the filtering.

16. A method of filtering a packet data stream as claimed in claim 15 in which the continuous flux of data contained in the payload of transport packets is organised in the form of secondary data packets, the second digital filter acting to filter the packets based on the value of one or more elements of the header of the secondary packets of data.

17. A method of filtering a packet data stream as claimed in claim 15 or 16 in which the transmitted data is organised in an MPEG format.

18. A method of filtering a packet data stream as claimed in claim 17 in which the continuous flux of data contained in the payload of a filtered and stored MPEG packet is organised in the form of a packetised elementary stream.

19. A method of filtering a packet data stream as claimed in any of claims 16 to 18 in which data filtered by the second digital filter is then passed to an associated memory element for storage and/or to a processor for execution, depending on the results of the filtering.

20. A method of filtering a packet data stream as claimed in any preceding claim in which the method is carried out in parallel with a filtering of transport packet data according to the value of a packet ID used to divide out data to be sent in real time to one or more corresponding processor elements.

21. A method of filtering a packet data stream as claimed in any preceding claim in which the method is carried out in parallel with a filtering of transport packet data according to the value of the packet ID, followed by a further filtering of sections contained within the payload of a transport packet according to the value of the section header.

15. A method of filtering a packet data stream as transmitted in an digital audiovisual transmission system and received by a receiver/decoder characterised in that transport packet data is filtered at a first stage by a first digital filter according to the characteristics of the transport packet, header, selected filtered data from the payload corresponding to a continuous flux of data then being passed to a second digital filter for a second stage of filtering.

22. A receiver/decoder for a digital audiovisual transmission system comprising a first digital filter and a memory element, characterised in that transport packet data is filtered at a first stage by the first digital filter according to the characteristics of the transport packet header, selected data thereafter being passed directly to the memory element.

23. A receiver/decoder for a digital audiovisual transmission system comprising a first and second digital filter, characterised in that transport packet data is filtered at a first stage by the first digital filter, selected filtered data from the payload corresponding to a continuous flux of data then being passed to the second digital filter for a second stage of filtering.

24. A method of filtering a packet data stream substantially as herein described.

25. A receiver/decoder for a digital audiovisual transmission system substantially as herein described.