System and method for low power stereo perceptual audio coding using adaptive masking threshold

• US 20070162277A1
• Filed: 08/22/2006
• Published: 07/12/2007
• Est. Priority Date: 01/12/2006
• Status: Active Grant

• Current Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Inventors: Kurniawati, Evelyn, George, Sapna
• Granted Patent: US 8,332,216 B2
• Time in Patent Office: Days
• US Class Current: 704/200.100
• CPC Class Codes: G10L 19/02 using spectral analysis, e.g. transform vocoders or subband vocoders

Abstract

A method for stereo audio perceptual encoding of an input signal includes masking threshold estimation and bit allocation. The masking threshold estimation and bit allocation are performed once every two encoding processes. Another method for stereo audio perceptual encoding of an input signal includes performing a time-to-frequency transformation, performing a quantization, performing a bitstream formatting to produce an output stream, and performing a psychoacoustics analysis. The psychoacoustics analysis includes masking threshold estimation on a first of every two successive frames of the input signal.

Claims

1. A method for stereo audio perceptual encoding of an input signal, comprising:

masking threshold estimation; and

bit allocation;

wherein the masking threshold estimation and the bit allocation are performed once every two encoding processes.

2. The method of claim 1, wherein:

the masking threshold is reused based on characteristics of the input signal; and

when the input signal is stationary, the masking threshold is reused across frames.

3. The method of claim 2, wherein a bit distribution across channels is reused when the masking threshold is reused across frames.

4. The method of claim 1, wherein:

the masking threshold is reused based on characteristics of the input signal; and

when the input signal is of a transient characteristic, the masking threshold is reused across channels.

5. The method of claim 4, wherein a bit distribution across channels is set to an equal distribution when the masking threshold is reused across channels.

6. The method of claim 1, wherein the masking threshold is reused across channels or across frames according to one of seven possible pairs of window types used in a perceptual audio encoder.

7. The method of claim 1, where the masking threshold is reused by copying distortion controlling quantization parameters.

8. The method of claim 7, further comprising spectral hole patching applied prior to copying the distortion controlling quantization parameters, the spectral hole patching comprising linearly interpolating adjacent parameter values when an actual energy of a band is above the masking threshold.

9. A method for stereo audio perceptual encoding of an input signal, comprising:

performing a time-to-frequency transformation;

performing a quantization;

performing a bitstream formatting to produce an output stream; and

performing a psychoacoustics analysis including masking threshold estimation on a first of every two successive frames of the input signal.

10. The method of claim 9, further comprising performing a bit allocation on the first of every two successive frames of the input signal.

11. The method of claim 9, further comprising performing a bit distribution between channels on the first of every two successive frames of the input signal.

12. The method of claim 9, further comprising performing a bit distribution between frames on the first of every two successive frames of the input signal.

13. The method of claim 12, wherein results of the bit allocation are reused on a second of every two successive frames of the input signal.

14. The method of claim 9, wherein:

the estimated masking threshold is reused based on characteristics of the input signal; and

when the input signal is stationary, the masking threshold is reused across frames.

15. The method of claim 14, wherein a bit distribution across channels is reused when the masking threshold is reused across frames.

16. The method of claim 9, wherein:

the estimated masking threshold is reused based on characteristics of the input signal; and

when the input signal is of a transient characteristic, the masking threshold is reused across channels.

17. The method of claim 16, wherein a bit distribution across channels is set to an equal distribution when the masking threshold is reused across channels.

18. The method of claim 9, wherein the masking threshold is reused across channels or across frames according to one of seven possible pairs of window types used in a perceptual audio encoder.

19. The method of claim 9, wherein the estimated masking threshold is reused by copying distortion controlling quantization parameters.

20. The method of claim 19, further comprising spectral hole patching applied prior to copying the distortion controlling quantization parameters, the spectral hole patching comprising linearly interpolating adjacent parameter values when an actual energy of a band is above the masking threshold.