Method of processing data packets received on asynchronous networks, and device for implementing the method

• US 7,313,149 B2
• Filed: 11/05/2003
• Issued: 12/25/2007
• Est. Priority Date: 12/03/2002
• Status: Expired due to Fees

• Current Assignee: Orange S.A.
• Original Assignee: Orange S.A.
• Inventors: Deleam, David, Bouteille, Franck
• Primary Examiner(s): Pezzlo, John
• Application Number:
  US10/702,019
• Publication Number:
  US 20040146060A1
• Time in Patent Office: 1,511 Days
• Field of Search: 370/336, 370/337, 370/235, 370/347, 370/442, 370/412, 370/419, 370/428, 370/429
• US Class Current: 370/429
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9023 for implementing a jitter-buffer
• CPC Class Codes: H04L 49/9094 Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element

Abstract

The digital data packets received contain data describing successive time segments of a signal stream to be restored, for example audio. Elements obtained from the packets received are recorded in a buffer memory organized in first-in first-out mode. A burst of packets fulfilling a certain burst size condition is detected a priori, on the basis of a reception delay evaluated in response to the reception of a first packet of the burst. The content of the buffer memory is controlled by accounting for the detection of the burst fulfilling the size condition.

Claims

1. A method of processing digital data packets received, containing description data for successive time segments of a signal stream to be restored, comprising the steps of:

recording elements obtained from the packets received in a buffer memory;

delivering elements recorded in the buffer memory in first-in first-out mode;

detecting a priori a burst of packets fulfilling a burst size condition on the basis of a reception delay evaluated in response to the reception of a first packet of the burst; and

controlling a content of the buffer memory by accounting for the detection of the burst fulfilling said size condition.

2. The method as claimed in claim 1, further comprising the step of evaluating a burst size upon arrival of a packet, the size condition being expressed as a threshold value with which the evaluated burst size is compared.

3. The method as claimed in claim 2, wherein the threshold is selected by taking account of a type of application and/or a type and behavior of the network.

4. The method as claimed in claim 2, wherein the evaluation of the burst size is based on parameters comprising an instant of arrival of the packets.

5. The method as claimed in claim 4, wherein the parameters on which the evaluation of the burst size is based further comprise parameters included in the packets.

6. The method as claimed in claim 5, wherein said parameters included in the packets comprise a sequence number and/or a timestamp included in packets of the RTP protocol.

7. The method as claimed in claim 1, wherein the control of the content of the buffer memory comprises taking into account a target value for the fill of the buffer memory at the end of the processing of the detected burst.

8. The method as claimed in claim 7, further comprising the step of determining the target value as a function of the fill of the buffer memory in phases where no bursts fulfilling the size condition are detected and/or as a function of the application.

9. The method as claimed in claim 1, wherein the control of the content of the buffer memory comprises taking into account a packets reception capacity by a an item of equipment incorporating the buffer memory.

10. The method as claimed in claim 9, wherein the packets reception capacity is estimated as a maximum of the numbers of packets received over a determined duration following each detection of a burst fulfilling said size condition.

11. The method as claimed in claim 1, wherein the control of the content of the buffer memory comprises deleting at least some of the elements obtained from the packets of the detected burst, before recording said elements in the buffer memory.

12. The method as claimed in claim 11, wherein all the elements obtained from the packets of the detected burst are deleted without recording them in the buffer memory.

13. The method as claimed in claim 11, wherein only part of the elements obtained from the packets of the detected burst is deleted without recording them in the buffer memory.

14. The method as claimed in claim 13, further comprising the step of evaluating a size of the burst fulfilling the size condition, wherein the deleted part represents a signal quantity corresponding substantially to the difference between a signal quantity corresponding to the evaluated burst size and a signal quantity corresponding to a target value for the fill of the buffer memory at the end of the detected burst.

15. The method as claimed in claim 13, wherein the deleted part is placed at the start of the detected burst.

16. The method as claimed in claim 13, wherein the deleted part is placed at the end of the detected burst.

17. The method as claimed in claim 13, wherein the deleted part is placed in the detected burst as a function of an activity cue of the signal to be restored.

18. The method as claimed in claim 17, wherein the activity cue of the signal to be restored is obtained in response to an at least partial decoding of the content of the packets.

19. The method as claimed in claim 13, wherein the deleted part is so placed as to prevent the buffer memory from becoming empty while the burst is processed.

20. The method as claimed in claim 19, further comprising the step of evaluating a signal quantity which could be missing on account of an empty state of the buffer memory while the burst is processed if the deleted part was placed at the start of the detected burst, and when the evaluated quantity is non zero, placing said part in the detected burst in such a way as to record in the buffer memory elements obtained from at least one packet received at the start of the detected burst and representing a signal quantity at least equal to the evaluated quantity.

21. The method as claimed in claim 1, wherein the elements recorded in the buffer memory comprise signal coding data extracted from the packets received.

22. The method as claimed in claim 1, wherein the elements recorded in the buffer memory comprise time segments of the signal stream to be restored, obtained by decoding the content of the packets received.

23. A device for receiving digital data packets representative of successive time segments of a signal to be restored, comprising a buffer memory organized in first-in first-out mode so as to receive elements obtained from the packets received, means for detecting a priori a burst of packets fulfilling a burst size condition on the basis of a reception delay evaluated in response to the reception of a first packet of the burst, and means for controlling the content of the buffer memory by accounting for the detection of the burst fulfilling said size condition.

24. The device as claimed in claim 23, further comprising means for evaluating a burst size upon arrival of a packet, the size condition being expressed as a threshold value with which the evaluated burst size is compared.

25. The device as claimed in claim 24, wherein the evaluation of the burst size is based on parameters comprising an instant of arrival of the packets.

26. The device as claimed in claim 25, wherein the parameters on which the evaluation of the burst size is based further comprise parameters included in the packets.

27. The device as claimed in claim 23, wherein the control of the content of the buffer memory comprises taking into account a target value for the fill of the buffer memory at the end of the processing of the detected burst.

28. The device as claimed in claim 23, wherein the means for controlling the content of the buffer memory comprise means for taking into account a packets reception capacity by a an item of equipment incorporating the buffer memory.

29. The device as claimed in claim 23, wherein the means for controlling the content of the buffer memory comprise means for deleting at least some of the elements obtained from the packets of the detected burst, before recording said elements in the buffer memory.

30. The device as claimed in claim 29, wherein only part of the elements obtained from the packets of the detected burst is deleted without recording them in the buffer memory.

31. The device as claimed in claim 30, further comprising means for evaluating a size of the burst fulfilling the size condition, wherein the deleted part represents a signal quantity corresponding substantially to the difference between a signal quantity corresponding to the evaluated burst size and a signal quantity corresponding to a target value for the fill of the buffer memory at the end of the detected burst.

32. The device as claimed in claim 31, wherein the deleted part is placed in the detected burst as a function of an activity cue of the signal to be restored.