METHOD AND SYSTEM FOR DYNAMIC RANGE CONTROL IN AN AUDIO PROCESSING SYSTEM

• US 20100204996A1
• Filed: 02/09/2009
• Published: 08/12/2010
• Est. Priority Date: 02/09/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Khanduri, Prakash, Sollenberger, Nelson, Patel, Ronish, Zeng, Hanks, Kasiske, Ken
• Granted Patent: US 8,626,516 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: H03G 9/025 frequency-dependent volume compression or expansion, e.g. multiple-band systems H03G9/10, H03G9/18 take precedence
• CPC Class Codes: H04R 2430/03 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

Methods and systems for dynamic range control in an audio processing system are disclosed and may include controlling a dynamic range of an audio signal by expanding the dynamic range utilizing a dynamic expander, and dividing the audio signal into a plurality of frequency bands. Each of the bands may be individually compressed utilizing a multi-band compressor. A sum of the individually compressed frequency bands may be compressed utilizing a full-band compressor. The audio signal may be filtered utilizing a pre-emphasis filter, such as an infinite impulse response filter and may be divided into frequency bands utilizing one or more finite impulse response filters and/or delay modules. The dynamic expander may include adaptive thresholds and an envelope detector. Each of the frequency bands may be compressed utilizing syllabic compression in the multi-band compressor. The compressed sum of compressed plurality of bands may be processed utilizing an audio CODEC.

Claims

1. A method for processing signals, the method comprising:

dividing an audio signal into a plurality of frequency bands;

individually compressing each of said plurality of frequency bands; and

compressing a sum of said individually compressed each of said plurality of frequency bands.

2. The method according to claim 1, comprising pre-emphasis filtering said audio signal.

3. The method according to claim 2, wherein said pre-emphasis filtering comprises infinite impulse response filtering said audio signal.

4. The method according to claim 1, comprising finite impulse response filtering said audio signal to enable said dividing of said audio signal into said plurality of frequency bands.

5. The method according to claim 1, comprising delaying said audio signal to enable said dividing of said audio signal into said plurality of frequency bands.

6. The method according to claim 1, comprising compressing each of said plurality of frequency bands utilizing syllabic compression.

7. The method according to claim 1, comprising expanding said dynamic range of said audio signal utilizing a dynamic expander in a hardware audio CODEC.

8. The method according to claim 1, comprising expanding said dynamic range of said audio signal utilizing a dynamic expander in a processor.

9. The method according to claim 7, wherein said dynamic expander comprises adaptive thresholds.

10. The method according to claim 7, wherein said dynamic expander comprises an envelope detector.

11. The method according to claim 1, comprising individually compressing each of said plurality of frequency bands utilizing a multi-band compressor in a hardware audio CODEC.

12. The method according to claim 10, wherein said multi-band compressor comprises a plurality of sub-band compressors.

13. The method according to claim 1, comprising compressing said summed individually compressed frequency bands utilizing a full-band compressor in a hardware audio CODEC.

14. A system for processing audio signals, the system comprising:

one or more circuits for use in a device that processes audio, wherein said one or more circuits are operable to divide an audio signal into a plurality of frequency bands;

said one or more circuits are operable to individually compress each of said plurality of frequency bands; and

said one or more circuits are operable to compress a sum of said individually compressed each of said plurality of frequency bands.

15. The system according to claim 14, wherein said one or more circuits are operable to filter said audio signal utilizing pre-emphasis filtering.

16. The system according to claim 15, wherein said one or more circuits are operable to perform infinite impulse response filtering for said pre-emphasis filtering.

17. The system according to claim 14, wherein said one or more circuits are operable to perform finite impulse response filtering for said division of said audio signal into said plurality of frequency bands.

18. The system according to claim 14, wherein said one or more circuits are operable to delay said audio signal for said dividing of said audio signal into said plurality of frequency bands.

19. The system according to claim 14, wherein said one or more circuits are operable to perform syllabic compression for said compressing of said each of said plurality of frequency bands.

20. The system according to claim 14, wherein said one or more circuits comprise a dynamic expander in a hardware audio CODEC, wherein said one or more circuits are operable to perform said dynamic expansion of said dynamic range of said audio signal.

21. The system according to claim 14, wherein said one or more circuits comprise a processor, and said one or more circuits are operable to perform said dynamic expansion of said dynamic range of said audio signal.

22. The system according to claim 20, wherein said dynamic expander comprises adaptive thresholds.

23. The system according to claim 20, wherein said dynamic expander comprises an envelope detector.

24. The system according to claim 14, wherein said one or more circuits comprise a multi-band compressor in a hardware audio CODEC, and said one or more circuits are operable to perform said individual compression of each of said plurality of frequency bands.

25. The system according to claim 24, wherein said multi-band compressor comprises a plurality of sub-band compressors.

26. The system according to claim 14, wherein said one or more circuits comprise a full-band compressor in a hardware audio CODEC, and said one or more circuits are operable to perform said compression of said summed individually compressed frequency bands.