Transient signal encoding method and device, decoding method and device, and processing system

• US 8,063,809 B2
• Filed: 06/29/2011
• Issued: 11/22/2011
• Est. Priority Date: 12/29/2008
• Status: Active Grant

• Current Assignee: Crystal Clear Codec, LLC
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Chen, Longyin, Zhang, Qing, Miao, Lei, Hu, Chen, Liu, Zexin, Taddei, Herve Marcel, Xiao, Wei
• Primary Examiner(s): Nguyen; Khai M
• Application Number:
  US13/172,652
• Publication Number:
  US 20110251846A1
• Time in Patent Office: 146 Days
• Field of Search: 341/76, 341/87, 341/155, 381/56, 381/66, 381/94.2, 704/205, 704/208, 704/214, 704/225, 704/226, 704/239, 704/253, 704/254, 704/500, 704/501, 704/E11.006, 704/E19.014, 704/E19.012, 704/E21.002, 704/E21.007
• US Class Current: 341/155
• CPC Class Codes: G10L 19/025 Detection of transients or attacks for time/frequency resolution switching

Abstract

A transient signal encoding method and device, decoding method and device, and processing system, where the transient signal encoding method includes: obtaining a reference sub-frame where a maximal time envelope having a maximal amplitude value is located from time envelopes of all sub-frames of an input transient signal; adjusting an amplitude value of the time envelope of each sub-frame before the reference sub-frame in such a way that a first difference is greater than a preset first threshold, in which the first difference is a difference between the amplitude value of the time envelope of each sub-frame before the reference sub-frame and the amplitude value of the maximal time envelope; and writing the adjusted time envelope into bitstream.

Claims

1. A transient signal encoding method, comprising:

obtaining a reference sub-frame where a maximal time envelope having a maximal amplitude value is located from time envelopes of all sub-frames of an input transient signal;

adjusting an amplitude value of the time envelope of each sub-frame before the reference sub-frame in such a way that a first difference is greater than a preset first threshold, wherein the first difference is a difference between the amplitude value of the time envelope of each sub-frame before the reference sub-frame and the amplitude value of the maximal time envelope; and

writing the adjusted time envelope into a bitstream.

2. The transient signal encoding method according to claim 1, further comprising:

calculating an average amplitude value of the time envelopes of each sub-frame after the reference sub-frame; and

adjusting the amplitude value of the time envelope of each sub-frame after the reference sub-frame in such a way that a second difference is greater than a preset second threshold when the average amplitude value is lower than or equal to a preset reference value, wherein the second difference is a difference between the amplitude value of the time envelope of each sub-frame after the reference sub-frame and the amplitude value of the maximal time envelope.

3. The transient signal encoding method according to claim 2, wherein after adjusting the amplitude value of the time envelope of each sub-frame other than the reference sub-frame, the method further comprises:

adjusting an amplitude value of the time envelope of the reference sub-frame in such a way that an average energy of the adjusted time envelope of each sub-frame of the, transient signal is greater than a preset third threshold.

4. The transient signal encoding method according to claim 1, further comprising:

determining a signal type of the input signal; and

writing a signal type information into the encoding bitstream, wherein the signal type comprises a transient signal or a non-transient signal.

5. The transient signal encoding method according to claim 4, wherein the determining the signal type of the input signal comprises:

forming a long frame with a preset number of consecutive frames in the input signal, and calculating an average energy of the long frame;

dividing the long frame into multiple sub-frames, and calculating an average energy of each sub-frame;

calculating a third difference and a fourth difference respectively, wherein the third difference is a maximal difference between the average energy of each sub-frame and the average energy of the long frame, and wherein the fourth difference is a maximal difference between average energies of two consecutive sub-frames; and

determining that the input signal is a transient signal when the average energy of the long frame is greater than a fourth threshold, the third difference is greater than a fifth threshold, and the fourth difference is greater than a sixth threshold;

otherwise, determining that the input signal is a non-transient signal.

6. A transient signal decoding method, comprising:

obtaining a reference sub-frame where a maximal time envelope having a maximal amplitude value is located from time envelopes of all sub-frames of a pre-obtained signal having a signal type of a transient signal;

adjusting an amplitude value of the time envelope of each sub-frame before the reference sub-frame in such a way that a first difference is greater than a preset first threshold, wherein the first difference is a difference between the amplitude value of the time envelope of each sub-frame before the reference sub-frame and the amplitude value of the maximal time envelope; and

modifying a pre-obtained time-domain signal according to the adjusted time envelope, so as to obtain a recovered transient signal.

7. The transient signal decoding method according to claim 6, further comprising:

calculating an average amplitude value of the time envelope of each sub-frame after the reference sub-frame; and

adjusting the amplitude value of the time envelope of each sub-frame after the reference sub-frame in such a way that a second difference is greater than a preset second threshold when the average amplitude value is lower than or equal to a preset reference value, wherein the second difference is a difference between the amplitude value of the time envelope of each sub-frame after the reference sub-frame and the amplitude value of the maximal time envelope.

8. The transient signal decoding method according to claim 7, wherein after adjusting the amplitude value of the time envelope of each sub-frame other than the reference sub-frame, the method further comprises:

adjusting an amplitude value of the time envelope of the reference sub-frame in such a way that an average energy of the adjusted time envelope of each sub-frame of the transient signal is greater than a preset third threshold.

9. The transient signal decoding method according to claim 6, wherein before the modifying the pre-obtained time-domain signal according to the adjusted time envelope, the method further comprises:

selecting a preset number of sampling points in the reference sub-frame; and

adjusting signal amplitude of each of the selected sampling points in such a way that a fifth difference is greater than a seventh threshold, wherein the fifth difference is a difference between the signal amplitude value of each of the selected sampling points and a maximal amplitude value of the reference sub-frame.

10. A transient signal encoding device, comprising:

a reference sub-frame obtaining module, configured to obtain a reference sub-frame where a maximal time envelope having a maximal amplitude value is located from time envelopes of all sub-frames of an input transient signal;

a first amplitude value adjusting module, configured to adjust an amplitude value of the time envelope of each sub-frame before the reference sub-frame in such a way that a first difference is greater than a preset first threshold, wherein the first difference is a difference between the amplitude value of the time envelope of each sub-frame before the reference sub-frame and the amplitude value of the maximal time envelope; and

a bitstream writing module, configured to write the adjusted time envelope into a bitstream.

11. The transient signal encoding device according to claim 10, further comprising:

an average amplitude value calculation module, configured to calculate an average amplitude value of the time envelopes of each sub-frame after the reference sub-frame; and

a second amplitude value adjusting module, configured to adjust the amplitude value of the time envelope of each sub-frame after the reference sub-frame in such a way that a second difference is greater than a preset second threshold when the average amplitude value is lower than or equal to a preset reference value, wherein the second difference is a difference between the amplitude value of the time envelope of each sub-frame after the reference sub-frame and the amplitude value of the maximal time envelope.

12. The transient signal encoding device according to claim 11, further comprising:

a third amplitude value adjusting module, configured to adjust an amplitude value of the time envelope of the reference sub-frame in such a way that an average energy of the adjusted time envelope of each sub-frame of the transient signal is greater than a preset third threshold, after the amplitude value of the time envelope of each sub-frame other than the reference sub-frame is adjusted.

13. The transient signal encoding device according to claim 12, further comprising:

a signal type determination module, configured to determine a signal type of the input signal, and write signal type information in the encoding bitstream, wherein the signal type comprises a transient signal or a non-transient signal.

14. The transient signal encoding device according to claim 13, wherein the signal type determination module comprises:

a long frame average energy calculation unit, configured to form a long frame with a preset number of consecutive frames in the input signal and calculate an average energy of the long frame;

a sub-frame average energy calculation unit, configured to divide the long frame into multiple sub-frames and calculate an average energy of each sub-frame;

a difference calculation unit, configured to calculate a third difference and a fourth difference respectively, wherein the third difference is a maximal difference between the average energy of each sub-frame and the average energy of the long frame, and the fourth difference is a maximal difference between average energies of two consecutive sub-frames; and

a signal type determination unit, configured to determine that the input signal is a transient signal when the average energy of the long frame is greater than a fourth threshold, the third difference is greater than a fifth threshold, and the fourth difference is greater than a sixth threshold;

otherwise, determine that the input signal is a non-transient signal.