Method and apparatus for the compression and decompression of audio files using a chaotic system

• US 7,215,776 B1
• Filed: 06/20/2000
• Issued: 05/08/2007
• Est. Priority Date: 11/09/1999
• Status: Expired due to Fees

• Current Assignee: University of New Hampshire
• Original Assignee: University of New Hampshire
• Inventors: Short, Kevin M.
• Primary Examiner(s): Moazzami; Nasser
• Assistant Examiner(s): Hoffman; Brandon
• Application Number:
  US09/597,101
• Time in Patent Office: 2,513 Days
• Field of Search: 380/263, 369/100
• US Class Current: 380/263
• CPC Class Codes: G10L 19/097 using prototype waveform decomposition or prototype waveform interpolative [PWI] coders
• CPC Class Codes: H04L 2209/30 Compression, e.g. Merkle-Damgard construction
• CPC Class Codes: H04L 9/001 using chaotic signals

Abstract

A system for the compression and decompression of sections of audio files is provided. A library of basic waveforms is produced by applying selected digital initialization codes to a chaotic system. Each basic waveform is in one-to-one correspondence with an initialization code. A weighted sum of the selected basic waveforms is used to approximate a section of audio file. The basic waveforms are then discarded and only the weighting factors and the corresponding initialization codes are stored in a compressed audio file. When the compressed audio file is decompressed for playback, the stored initialization codes are stripped out and applied to a similar chaotic system to regenerate the basic waveforms, which are recombined according to the stored weighting factors to reproduce the original section of audio file.

Claims

1. A method of compressing an audio file comprising:

choosing a chaotic system;

applying selected digital initialization codes to the chaotic system such that each initialization code produces a periodic orbit and stabilizes the otherwise unstable orbit;

generating a basic waveform for each periodic orbit such that the basic waveform is in a one-to-one correspondence to the initialization code for the periodic orbit;

selecting and analyzing a section of audio file to be compressed;

selecting the basic waveforms to be used and storing their corresponding initialization codes;

transforming the section of audio file and the selected basic waveforms to a proper frequency range and storing frequency information describing the transformation;

calculating weighting factors to create a weighted sum of the selected basic waveforms to approximate the section of audio file and storing the weighting factors; and

combining the stored initialization codes, the stored frequency information and the stored weighting factors to comprise a compressed audio file.

2. The method of compressing an audio file of claim 1 further comprising the steps of:

removing from the weighted sum of the selected basic waveforms any selected basic waveforms not deemed necessary to approximate the section of audio file; and

removing the corresponding stored initialized codes.

3. The method of compressing an audio file of claim 1 further comprising the step of identifying trends over sections of compressed audio file and replacing the stored weighting factors for the sections of compressed audio file by a suitable function.

4. A system for compressing an audio file comprising:

means for choosing a chaotic system;

means for applying selected digital initialization codes to the chaotic system such that each initialization code produces a periodic orbit and stabilizes the otherwise unstable orbit;

means for generating a basic waveform for each periodic orbit such that the basic waveform is in a one-to-one correspondence to the initialization code for the periodic orbit;

means for selecting and analyzing a section of audio file to be compressed;

means for selecting the basic waveforms to be used and means for storing their corresponding initialization codes;

means for transforming the section of audio file and the selected basic waveforms to a proper frequency range and means for storing frequency information describing the transformation;

means for calculating weighting factors to create a weighted sum of the selected basic waveforms to approximate the section of audio file and means for storing the weighting factors; and

means for combining the stored initialization codes, the stored frequency information and the stored weighting factors to comprise a compressed audio file.

5. The system of claim 4 further comprising:

means for removing from the weighted sum of the selected basic waveforms any selected basic waveforms not deemed necessary to approximate the section of audio file; and

means for removing the corresponding stored initialization codes.

6. The system of claim 4 further comprising the means for identifying trends over sections of compressed audio file and the means for replacing the stored weighting factors for the sections of compressed audio file by a suitable function.

7. A system for compressing an audio file comprising:

a chaotic system;

a comparison controller to apply selected digital initialization codes to the chaotic system to produce periodic orbits and stabilize the otherwise unstable orbits and to produce a basic waveform for each periodic orbit that is in a one-to-one correspondence with the initialization code for the periodic orbit;

a waveform comparator to analyze a section of audio file to be compressed to select basic waveforms to be used; and

to store their corresponding initialization codes;

a waveform weighter to calculate, and store, weighting factors to create a weighted sum of the selected basic waveforms to approximate the section of audio file; and

a storage device to store the stored initialization codes and the stored weighting factors.

8. A method comprising:

choosing a compressed audio file;

stripping stored initialization codes out of the compressed audio file;

applying the stored initialization codes to a chaotic system identical to the chaotic system used in producing the compressed audio file to produce the corresponding basic waveforms such that each initialization code produces a periodic orbit and stabilizes the otherwise unstable orbit;

stripping stored weighting factors out of the compressed audio file; and

combining corresponding basic waveforms according to the stored weighting factors to reproduce the original section of audio file.

9. A system comprising:

means for choosing a compressed audio file;

means for stripping stored initialization codes out of the compressed audio file;

means for applying the stored initialization codes to a chaotic system identical to the chaotic system used in producing the compressed audio file to produce the corresponding basic waveforms such that each initialization code produces a periodic orbit and stabilizes the otherwise unstable orbit;

means for stripping stored weighting factors out of the compressed audio file; and

means for combining corresponding basic waveforms according to the stored weighting factors to reproduce the original section of audio file.

10. A method of compressing an audio signal, using a chaotic system, comprising:

causing the chaotic system to assume a periodic orbit;

generating a periodic waveform for the periodic orbit;

weighting the periodic waveform to approximate at least a portion of the audio signal; and

merging at least one initialization code and a representation of the weighting, to compress the portion of the audio signal.

11. The method of claim 10, including stabilizing the periodic orbit.

12. A method of compressing an audio signal, using a chaotic system, comprising:

causing the chaotic system to assume a plurality of periodic orbits;

generating a periodic waveform for each of a subset of the periodic orbits;

weighting a subset of the generated periodic waveforms to approximate at least a portion of the audio signal; and

merging at least one initialization code and information representative of the weighting, to compress the portion of the audio signal.

13. The method of claim 12, including assigning a zero weight to at least one of the subset of generated periodic waveforms.

14. A method of compressing an audio signal, using a chaotic system, comprising:

causing the chaotic system to assume a plurality of periodic orbits;

generating a periodic waveform for each of the periodic orbits;

weighting the periodic waveforms to approximate the audio signal; and

merging at least one initialization code and information representative of the weighting, to compress the audio signal.

15. A method of compressing an audio signal, using a chaotic system, comprising:

causing the chaotic system to assume at least one periodic orbit by applying at least one initialization code to the chaotic system;

generating a periodic waveform for each of a subset of the at least one periodic orbit;

weighting a subset of the generated periodic waveforms to approximate at least a portion of the audio signal; and

merging the at least one initialization code and information representative of the weighting, to compress the audio signal.

16. A method of compressing an audio signal, using a chaotic system, comprising:

causing the chaotic system to assume a periodic orbit;

generating a periodic waveform for the periodic orbit;

weighting the periodic waveform to approximate a first portion of the audio signal;

identifying a correlation between data in the first portion of the audio signal and data in at least one other portion of the audio signal;

merging at least one initialization code, a representation of the weighting, and a representation of the correlation, to represent the first portion of the audio signal and the at least one other portion of the audio signal, to compress the audio signal.

17. A method of decompressing a compressed representation of a first audio signal, the compressed representation produced using a first chaotic system, comprising:

causing a second chaotic system, identical to the first chaotic system, to assume a predetermined periodic orbit;

generating a periodic waveform for the periodic orbit; and

applying a predetermined weighting to the periodic waveform to produce at least a portion of a second audio signal identical to at least a portion of the first audio signal.

18. The method of claim 17, including stabilizing the periodic orbit.

19. A method of decompressing a compressed representation of a first audio signal, the compressed representation produced using a first chaotic system, comprising:

causing a second chaotic system, identical to the first chaotic system, to assume at least one predetermined periodic orbit;

generating a predetermined periodic waveform for each of a subset of the at least one predetermined periodic orbit; and

applying a predetermined weighting to at least one generated predetermined periodic waveform to produce at least a portion of a second audio signal perceived by a listener to be identical to at least a portion of the first audio signal.

20. A method of decompressing a compressed representation of a first audio signal, the compressed representation produced using a first chaotic system, comprising:

causing a second chaotic system, identical to the first chaotic system, to assume a plurality of predetermined periodic orbits;

generating a predetermined periodic waveform for each of a subset of the predetermined periodic orbits; and

applying a predetermined weighting to at least one generated periodic waveform to produce at least a portion of a second audio signal perceived by a listener to be identical to at least a portion of the first audio signal.

21. A method of decompressing a compressed representation of a first audio signal, the compressed representation produced using a first chaotic system, comprising:

causing a second chaotic system, identical to the first chaotic system, to assume a predetermined periodic orbit;

generating a periodic waveform for the periodic orbit;

applying a predetermined weighting to the periodic waveform to produce a first portion of a second audio signal substantially identical to a first portion of the first audio signal; and

applying, to the first portion of the second audio signal, a predetermined correlation between data in the first portion of the first audio signal and data in at least one other portion of the first audio signal, to produce at least one other portion of the second audio signal perceived by a listener to be identical to the at least one other portion of the first audio signal.