Signal encoding

• US 20050240399A1
• Filed: 11/22/2004
• Published: 10/27/2005
• Est. Priority Date: 04/21/2004
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Makinen, Jari M.
• Granted Patent: US 8,244,525 B2
• Time in Patent Office: Days
• US Class Current: 704/223
• CPC Class Codes: G10L 19/22 Mode decision, i.e. based on audio signal content versus external parameters

Abstract

A method for encoding a frame in an encoder of a communication system, said method comprising the steps of: calculating a first set of parameters associated with the frame, wherein said first set of parameters comprises filter bank parameters; selecting, in a first stage, one of a plurality of encoding methods based on the first set of parameters one of modes for encoding; calculating a second set of parameters associated with the frame; selecting, in a second stage, one of the plurality of encoding methods based on the result of the first stage selection and the second set of parameters one of modes for encoding; and encoding the frame using the selected encoding excitation method from the second stage.

Claims

1. A method for encoding a frame in an encoder of a communication system, said method comprising the steps of:

calculating a first set of parameters associated with a frame, wherein said first set of parameters comprises filter bank parameters;

selecting, in a first stage, one of a plurality of encoding methods based on predetermined conditions associated with the first set of parameters;

calculating a second set of parameters associated with the frame;

selecting, in a second stage, one of the plurality of encoding methods based on a result of the first stage selection and the second set of parameters; and

encoding the frame using the selected encoding method from the second stage.

2. A method according to claim 1, wherein the plurality of encoding methods comprises a first excitation method and a second excitation method

3. A method according to claim 1, wherein said first set of parameters are based on energy levels of one or more frequency bands associated with the frame.

5. A method according to claim 1, wherein said second set of parameters comprises at least one of spectral parameters, LTP parameters and correlation parameters associated with the frame.

6. A method according to claim 2, wherein the first excitation method is algebraic code excited linear prediction excitation.

7. A method according to claim 2, wherein the second excitation method is transform coding excitation.

8. A method according to claim 2, wherein, when the frame is encoded using the second excitation method, the method for encoding further comprises:

selecting a length of the frame encoded using the second excitation method based on the selecting at the first stage and the second stage.

9. A method according to claim 8, wherein the selection of the length of the encoded frame is dependent on a signal to noise ratio of the frame.

10. A method according to claim 1, wherein the method further comprises the step of providing an AMR-WB+ encoder.

11. A method according to claim 1, wherein the calculating step further comprises calculating a first set of parameters associated with an audio frame.

12. A method according to claim 11, wherein the audio frame comprises speech or non-speech.

13. A method according to claim 12, wherein the non-speech comprises music.

4. A method for encoding a frame in an encoder of a communication system, said method comprising the steps of:

calculating a first set of parameters associated with a frame, wherein said first set of parameters comprises filter bank parameters;

bypassing, in a first stage under certain predetermined conditions associated with the first set of parameters, selection of an encoding method from a plurality of encoding methods;

calculating a second set of parameters associated with the frame;

selecting, in a second stage, one of the plurality of encoding methods based on a result of the first stage selection and the second set of parameters; and

encoding the frame using the selected encoding method from the second stage.

14. An encoder for encoding a frame in a communication system, said encoder comprising:

a first calculation module configured to calculate a first set of parameters associated with a frame, wherein said first set of parameters comprises filter bank parameters;

a first stage selection module configured to select one of a plurality of encoding methods based on predetermined conditions associated with the first set of parameters;

a second calculation module configured to calculate a second set of parameters associated with the frame;

a second stage selection module configured to select one of the plurality of encoding methods based on the result of the first stage selection module and the second set of parameters; and

an encoding module configured to encode the frame using the selected encoding method from the second stage selection module.

15. An encoder according to claim 14, wherein the plurality of encoding methods comprises a first excitation method and a second excitation method.

16. An encoder according to claim 15, wherein the first excitation method comprises algebraic code excited linear prediction excitation.

17. An encoder according to claim 15, wherein the second excitation method comprises transform coding excitation.

18. An encoder according to claim 14, wherein said first set of parameters are based on energy levels of one or more frequency bands associated with the frame.

19. An encoder according to claim 14, wherein the first stage selection module is configured to select no encoding method based on different predetermined conditions of said first set of parameters.

20. An encoder according to claim 14, wherein said second set of parameters comprises at least one of spectral parameters, LTP parameters and correlation parameters associated with the frame.

21. An encoder according to claim 15 further comprising:

a third stage selection module configured to select a length of the frame encoded using the second excitation method based on the selecting at the first stage selection module and the second stage selection module.

22. An encoder according to claim 14, wherein the first stage selection module selects a length of the encoded frame based on a signal to noise ratio of the frame.

23. An encoder according to claim 14, wherein the encoder comprises an AMR-WB+ encoder.

24. An encoder according to claim 14, wherein said calculation modules calculate a set of parameters associated with an audio frame.

25. An encoder according to claim 24, wherein the audio frame comprises speech or non-speech.

26. An encoder according to claim 25, wherein the non-speech comprises music.

27. A terminal comprising the encoder of claim 14.

28. A terminal according to claim 27, wherein said terminal is a signal processing device.

29. A terminal according to claim 27, wherein said terminal is a mobile terminal.

30. A method for encoding a frame in an encoder of a communication system, said method comprising the steps of:

calculating a first set of parameters associated with the frame, wherein said first set of parameters comprises filter bank parameters;

selecting, in a first stage, one of a first excitation method or second excitation method based on the first set of parameters;

encoding the frame using the selected excitation method.

31. An encoder for encoding a frame in a communication system, said encoder comprising:

first calculating means for calculating a first set of parameters associated with a frame, wherein said first set of parameters comprises filter bank parameters;

first selecting means for selecting, in a first stage, one of a plurality of encoding methods based on predetermined conditions associated with the first set of parameters;

second calculating means for calculating a second set of parameters associated with the frame;

second selecting means for selecting, in a second stage, one of the plurality of encoding methods based on a result of the first stage selection and the second set of parameters; and

encoding means for encoding the frame using the selected encoding method from the second stage.