Method, system and product for harmonic enhancement of encoded audio signals

• US 5,864,813 A
• Filed: 12/20/1996
• Issued: 01/26/1999
• Est. Priority Date: 12/20/1996
• Status: Expired due to Term

• Current Assignee: Qwest Communications International Incorporated (Lumen Technologies, Inc.)
• Original Assignee: MediaOne Group Inc. (Comcast Corporation), U S West Inc.
• Inventors: Case, Eliot M.
• Primary Examiner(s): Hudspeth, David R.
• Assistant Examiner(s): ZINTEL, HAROLD ALBERT
• Application Number:
  US08/771,512
• Time in Patent Office: 767 Days
• Field of Search: 704/208, 704/278, 704/233, 704/500, 704/501, 704/503, 704/504, 381/62, 381/119, 381/118
• US Class Current: 704/500
• CPC Class Codes: G10H 1/0041 in coded form
• CPC Class Codes: G10H 1/06 Circuits for establishing the harmonic content of tones , or other arrangements for changing the tone colour
• CPC Class Codes: G10H 2240/251 Mobile telephone transmission, i.e. transmitting, accessing or controlling music data wirelessly via a wireless or mobile telephone receiver, analog or digital, e.g. DECT GSM, UMTS smartphone, PDA or palmtop used for musical purposes G10H2230/015; mobile ringtone G10H2230/021
• CPC Class Codes: G10L 19/26 Pre-filtering or post-filtering

Abstract

A method, system and product are provided for harmonic enhancement of an encoded audio signal. The method includes receiving the encoded audio signal, the encoded audio signal having multiple frequency subbands, selecting one of the subbands having a data sample associated therewith, and generating a frequency doubled copy the data sample associated with the subband. The method also includes generating a new data sample for a second subband using the frequency doubled copied data sample, the second subband having a frequency greater than the first subband by one octave, and modifying the encoded audio signal to create an enhanced encoded audio signal having the new data sample associated with the second subband. The system includes control logic for performing the method. The product includes a storage medium having computer readable programmed instructions for performing the method.

Claims

1. A method for harmonic enhancement of an encoded audio signal, the method comprising:

receiving the encoded audio signal, the encoded audio signal having a plurality of frequency subbands;

selecting a first one of the plurality of subbands having a data sample associated therewith;

generating a frequency doubled copy of the data sample associated with the first one of the plurality of subbands;

generating a new data sample for a second one of the plurality of subbands using the frequency doubled copied data sample, the second one of the plurality of subbands having a frequency greater than the first one of the plurality of subbands by one octave; and

modifying the encoded audio signal to create an enhanced encoded audio signal having the new data sample associated with the second one of the plurality of subbands.

2. The method of claim 1 wherein the encoded audio signal comprises a perceptually encoded audio signal.

3. The method of claim 1 wherein generating a new data sample for a second one of the plurality of subbands comprises:

determining if the second one of the plurality of subbands has an existing data sample associated therewith;

if the second one of the plurality of subbands has an existing data sample associated therewith, adding the frequency doubled copied data sample to the existing data sample; and

if the second one of the plurality of subbands lacks an existing data sample associated therewith, setting the new data sample for the second one of the plurality of subbands equal to the frequency doubled copied data sample.

4. The method of claim 3 further comprising determining if the new data sample associated with the second one of the plurality of subbands exceeds a masking effect associated with the encoded audio signal.

5. The method of claim 4 wherein modifying the encoded audio signal includes reformatting bit and scaling information associated with the encoded audio signal.

6. A system for harmonic enhancement of an encoded audio signal, the system comprising:

a receiver for receiving the encoded audio signal, the encoded audio signal having a plurality of frequency subbands;

means for selecting a first one of the plurality of subbands having a data sample associated therewith; and

control logic operative to generate a frequency doubled copy of the data sample associated with the first one of the plurality of subbands, generate a new data sample for a second one of the plurality of subbands using the frequency doubled copied data sample, the second one of the plurality of subbands having a frequency greater than the first one of the plurality of subbands by one octave, and modify the encoded audio signal to create an enhanced encoded audio signal having the new data sample associated with the second one of the plurality of subbands.

7. The system of claim 6 wherein the encoded audio signal comprises a perceptually encoded audio signal.

8. The system of claim 6 wherein, to generate a new data sample for a second one of the plurality of subbands, the control logic is operative to determine if the second one of the plurality of subbands has an existing data sample associated therewith, if the second one of the plurality of subbands has an existing data sample associated therewith, add the frequency doubled copied data sample to the existing data sample, and if the second one of the plurality of subbands lacks an existing data sample associated therewith, set the new data sample for the second one of the plurality of subbands equal to the frequency doubled copied data sample.

9. The system of claim 8 wherein, to generate a new data sample for a second one of the plurality of subbands, the control logic is further operative to determine if the new data sample associated with the second one of the plurality of subbands exceeds a masking effect associated with the encoded audio signal.

10. The system of claim 9 wherein, to modify the encoded audio signal, the control logic is operative to reformat bit and scaling information associated with the encoded audio signal.

11. A product for harmonic enhancement of an encoded audio signal, the product comprising a storage medium having computer readable programmed instructions recorded thereon, the instructions operative to generate a frequency doubled copy of a data sample associated with a first one of a plurality of subbands associated with the encoded audio signal, generate a new data sample for a second one of the plurality of subbands using the frequency doubled copied data sample, the second one of the plurality of subbands having a frequency greater than the first one of the plurality of subbands by one octave, and modify the encoded audio signal to create an enhanced encoded audio signal having the new data sample associated with the second one of the plurality of subbands.

12. The product of claim 11 wherein the encoded audio signal comprises a perceptually encoded audio signal.

13. The product of claim 11 wherein, to generate a new data sample for a second one of the plurality of subbands, the instructions are operative to determine if the second one of the plurality of subbands has an existing data sample associated therewith, if the second one of the plurality of subbands has an existing data sample associated therewith, add the frequency doubled copied data sample to the existing data sample, and if the second one of the plurality of subbands lacks an existing data sample associated therewith, set the new data sample for the second one of the plurality of subbands equal to the frequency doubled copied data sample.

14. The product of claim 13 wherein, to generate a new data sample for a second one of the plurality of subbands, the instructions are further operative to determine if the new data sample associated with the second one of the plurality of subbands exceeds a masking effect associated with the encoded audio signal.

15. The product of claim 14 wherein, to modify the encoded audio signal, the instructions are operative to reformat bit and scaling information associated with the encoded audio signal.