Temporal Envelope Coding of Energy Attack Signal by Using Attack Point Location

• US 20100063811A1
• Filed: 09/04/2009
• Published: 03/11/2010
• Est. Priority Date: 09/06/2008
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: GH Innovation Incorporated
• Inventors: Gao, Yang
• Granted Patent: US 8,380,498 B2
• Time in Patent Office: Days
• US Class Current: 704/230
• CPC Class Codes: G10L 19/025 Detection of transients or attacks for time/frequency resolution switching

Abstract

A method of transceiving an audio signal is disclosed. An input audio signal is provided. It is determined whether an energy attack signal exists within the input audio signal and a decision flag is set if the energy attack signal exists. A temporal location of the energy attack point in the input audio signal is detected. Energy variations before and after the temporal location of an energy attack point are determined. The energy variations to produce quantized energy variations and a peak area energy of the input audio signal to produce a quantized peak area energy are quantized. The decision flag, the temporal location of the energy attack point, the quantized energy variations, and the quantized peak energy are transmitted.

Claims

1. A method of transceiving an audio signal, the method comprising:

providing an input audio signal;

determining whether an energy attack signal exists within the input audio signal;

setting a decision flag if the energy attack signal exists;

detecting a temporal location of the energy attack point in the input audio signal;

determining energy variations before and after the temporal location of an energy attack point;

quantizing the energy variations to produce quantized energy variations;

quantizing a peak area energy of the input audio signal to produce a quantized peak area energy; and

transmitting the decision flag, the temporal location of the energy attack point, the quantized energy variations and the quantized peak energy.

2. The method of claim 1, further comprising:

determining energy variations before and after the temporal location of an energy attack point;

quantizing the energy variations to produce quantized energy variations;

transmitting the quantized energy variations.

3. The method of claim 1, further comprising:

receiving the transmitted decision flag, temporal location of the energy attack point, and quantized peak energy; and

rebuilding a temporal envelope shape of the energy attack signal based on the received decision flag, temporal location of the energy attack point, and quantized peak energy.

4. The method of claim 3, further comprising:

receiving quantized energy variations; and

rebuilding a temporal envelope shape of the energy attack signal based on the received decision flag, temporal location of the energy attack point, quantized energy variations and quantized peak energy.

5. The method of claim 3, wherein rebuilding comprises estimating the temporal envelope by assuming that signal energy after the peak area decays.

6. The method of claim 3, further comprising, converting the temporal envelope shape into an output audio signal based on the rebuilding.

7. The method of claim 6, further comprising driving a loudspeaker with the output audio signal.

8. The method of claim 1, wherein transmitting comprises transmitting over a voice over internet protocol (VOIP) network.

9. The method of claim 1, wherein transmitting comprises transmitting over a cellular telephone network.

10. The method of claim 1, wherein determining whether the energy attack signal exists comprises:

determining one or more ratios between a peak magnitude and average magnitudes of the input audio signal; and

determining a ratio between two magnitudes of said adjacent small segments within the input audio signal.

11. The method of claim 1, wherein determining whether the energy attack signal exists comprises determining a voicing parameter that represents signal periodicity.

12. The method of claim 1, wherein determining whether the energy attack signal exists comprises determining pitch correlation or pitch gain within the input audio signal.

13. The method of claim 1, wherein determining whether the energy attack signal exists comprises searching for maximum energy area and/or said maximum energy increasing area from one small segment of the input audio signal to a next segment of the input audio signal.

14. The method of claim 1, further comprising shaping energy variations before the temporal location of an energy attack point, shaping comprising interpolating between a beginning level of a segment at the beginning of the frame and an ending level of the segment just before the attack point.

15. The method of claim 1, further comprising shaping energy variations after the temporal location of an energy attack point, shaping comprising interpolating between a beginning level of a segment just after the peak and an ending level of the segment at the end of the frame.

16. The method of claim 1, further comprising:

determining an average energy before the temporal location of an energy attack point;

quantizing the average energy before the temporal location of an energy attack point to produces a quantized average energy;

determining an energy variation after the temporal location of an energy attack point;

quantizing the energy variation after the temporal location of an energy attack point to produces a quantized energy variation; and

transmitting the quantized average energy and the quantized energy variation.

17. The method of claim 1, further comprising:

determining average energies before and after the temporal location of an energy attack point;

quantizing the average energies to produce quantized average energies; and

transmitting the quantized average energies.

18. The method of claim 16, wherein rebuilding further comprising improving the temporal envelope shape based on the received temporal location of the energy attack point, the quantized average energy and the quantized energy variation.

19. The method of claim 17, further rebuilding further comprising:

improving the temporal envelope shape based on the received temporal location of the energy attack point and the quantized average energies.

20. A method of transceiving an audio signal, the method comprising:

providing an input audio signal;

determining whether an energy attack signal exists within the input audio signal;

setting a decision flag if the energy attack signal exists;

detecting a temporal location of the energy attack point in the input audio signal; and

transmitting the decision flag and the temporal location of the energy attack point.

21. The method of claim 20, further rebuilding the temporal envelope shape further comprising improving the temporal envelope shape based on the received temporal location of the energy attack point.

22. A system for transmitting an input audio signal, the system comprising:

a transmitter comprising an audio coder, the audio coder configured to;

determine whether an energy attack signal exists within the input audio signal,

set a decision flag if the energy attack signal exists,

detect a temporal location of the energy attack point in the input audio signal,

quantize a peak area energy to produce a quantized peak area energy, and

transmit audio parameters comprising the decision flag, the temporal location of the energy attack point, and the quantized peak energy.

23. The system of claim 22, wherein the system is configured to operate over a voice over internet protocol (VOIP) system.

24. The system of claim 22, wherein the system is configured to operate over a cellular telephone network.

25. The system of claim 22, further comprising a receiver, the receiver comprising an audio decoder configured to receive the audio parameters and produce an output audio signal based on the received audio parameters, wherein the output audio signal comprises an improved temporal envelope shape based on the temporal location of the energy attack point.