Audio processing apparatus and method

• US 8,492,639 B2
• Filed: 12/03/2010
• Issued: 07/23/2013
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Saino, Keijiro
• Primary Examiner(s): Donels, Jeffrey
• Application Number:
  US12/960,310
• Publication Number:
  US 20110132179A1
• Time in Patent Office: 963 Days
• Field of Search: 846/29
• US Class Current: 84/629
• CPC Class Codes: G10H 1/0008 Associated control or indicating means
• CPC Class Codes: G10H 1/0091 Means for obtaining special acoustic effects combined with modulation G10H1/043
• CPC Class Codes: G10H 1/053 during execution only voice controlled instruments G10H5/005
• CPC Class Codes: G10H 1/0575 using a data store from which the envelope is synthesized tones synthesized from a data store G10H7/00
• CPC Class Codes: G10H 2210/066 for pitch analysis as part of wider processing for musical purposes, e.g. transcription, musical performance evaluation; Pitch recognition, e.g. in polyphonic sounds; Estimation or use of missing fundamental
• CPC Class Codes: G10H 2210/205 Amplitude vibrato, i.e. repetitive smooth loudness variation without pitch change or rapid repetition of the same note, bisbigliando, amplitude tremolo, tremulants percussion roll G10H2210/161
• CPC Class Codes: G10H 2210/211 Pitch vibrato, i.e. repetitive and smooth variation in pitch, e.g. as obtainable with a whammy bar or tremolo arm on a guitar non-repetitive smooth pitch variation, e.g. glissando G10H2220/221; repeatedly alternating stepwise in pitch between two notes G10H2210/191
• CPC Class Codes: G10H 2250/551 Waveform approximation, e.g. piecewise approximation of sinusoidal or complex waveforms
• CPC Class Codes: G10H 2250/621 Waveform interpolation
• CPC Class Codes: G10H 3/125 Extracting or recognising the pitch or fundamental frequency of the picked up signal
• CPC Class Codes: G10H 7/008 Means for controlling the transition from one tone waveform to another

Abstract

Phase setting section sets virtual phases in a frequency series of an audio signal. Unit wave extraction section extracts, from the frequency series, a unit wave of one cyclic period defined by the set virtual phases, for each of a plurality of time points. First generation section generates velocity information corresponding to a degree of compression/expansion, to a predetermined length, of the unit wave. Second generation section generates shape information indicative of a shape of a frequency spectrum of the unit wave having been adjusted. Variation component impartment section generates a variation component by use of the velocity information and shape information generated for the individual time points.

Claims

1. An audio processing apparatus comprising:

a phase setting section which sets virtual phases in a time series of character values representing a character element of an audio signal, the virtual phases representing phases of a periodic variation of the time series of character values;

a unit wave extraction section which extracts, from the time series of character values, a plurality of unit waves demarcated in accordance with the virtual phases set by said phase setting section, the unit waves being demarcated from each other cycle by cycle of the periodic variation of the time series of character values; and

an information generation section which generates, for each of the unit waves extracted by said unit wave extraction section, unit information indicative of a character of the unit wave.

2. The audio processing apparatus as claimed in claim 1, which further comprises a phase correction section which corrects the phases of the unit waves, extracted by said unit wave extraction section, so that the unit waves are brought into phase with each other, and wherein said information generation section generates the unit information for each of the unit waves having been subjected to phase correction by said phase correction section.

3. The audio processing apparatus as claimed in claim 1, which further comprises a time adjustment section which compresses or expands each of the unit waves extracted by said unit wave extraction section, and wherein said information generation section generates the unit information for each of the unit waves having been subjected to compression or expansion by said time adjustment section.

4. The audio processing apparatus as claimed in claim 3, wherein said information generation section includes a first generation section which, for each of the unit waves, generates, as the unit information, velocity information indicative of a character value variation velocity in the time series of character values in accordance a degree of the compression or expansion by said time adjustment section.

5. The audio processing apparatus as claimed in claim 1, wherein said information generation section includes a second generation section which, for each of the unit waves, generates, as the unit information, shape information indicative of a shape of a frequency spectrum of the unit wave.

6. The audio processing apparatus as claimed in claim 1, wherein the character element of the audio signal is a frequency or a sound volume.

7. The audio processing apparatus as claimed in claim 1, which further comprises a storage section which stores a set of a plurality of the unit information generated by said information generation section for individual ones of the unit waves.

8. The audio processing apparatus as claimed in claim 7, which further comprises:

a variation component generation section which generates a variation component, corresponding to the time series of character values, from the set of the unit information stored in said storage section;

a signal supply section which supplies an audio signal; and

a signal generation section which imparts the variation component, generated by the variation component generation section, to a character element of the supplied audio signal.

9. A computer-implemented method for processing an audio signal, said method comprising:

a step of setting virtual phases in a time series of character values representing a character element of an audio signal, the virtual phases representing phases of a periodic variation of the time series of character values;

a step of extracting, from the time series of character values, a plurality of unit waves demarcated in accordance with the virtual phases set by said step of setting, the unit waves being demarcated from each other cycle by cycle of the periodic variation of the time series of character values; and

a step of generating, for each of the unit waves extracted by said step of extracting, unit information indicative of a character of the unit wave.

10. A computer-readable medium storing a program for causing a processor to perform a method for processing an audio signal, said method comprising the steps of:

setting virtual phases in a time series of character values representing a character element of an audio signal, the virtual phases representing phases of a periodic variation of the time series of character values;

extracting, from the time series of character values, a plurality of unit waves demarcated in accordance with the virtual phases set by said step of setting, the unit waves being demarcated from each other cycle by cycle of the periodic variation of the time series of character values; and

generating, for each of the unit waves extracted by said step of extracting, unit information indicative of a character of the unit wave.

11. An audio processing apparatus comprising:

a storage section which stores a set of a plurality of unit information indicative of respective characters of a plurality of unit waves extracted from a time series of character values, representing a character element of an audio signal, in accordance with virtual phases set in the time series, the virtual phases representing phases of a periodic variation of the time series of character values, the unit waves being demarcated from each other cycle by cycle of the periodic variation of the time series of character values, the unit information each including velocity information to be used for control to compress or expand a time length of a corresponding one of the unit waves, and shape information indicative of a shape of a frequency spectrum of the corresponding unit wave;

a variation component generation section which generates a variation component, corresponding to the time series of character values, from the set of the unit information stored in said storage section; and

a signal generation section which impart the variation component, generated by said variation component generation section, to a character element of an input audio signal.

12. A computer-implemented method for processing an audio signal, said method comprising:

a step of accessing a storage section which stores a set of a plurality of unit information indicative of respective characters of a plurality of unit waves extracted from a time series of character values, representing a character element of an audio signal, in accordance with virtual phases set in the time series, the virtual phases representing phases of a periodic variation of the time series of character values, the unit waves being demarcated from each other cycle by cycle of the periodic variation of the time series of character values, the unit information each including velocity information to be used for control to compress or expand a time length of a corresponding one of the unit waves, and shape information indicative of a shape of a frequency spectrum of the corresponding unit wave;

a step of generating a variation component, corresponding to the time series of character values, from the set of the unit information stored in said storage section; and

a step of imparting the generated variation component to a character element of an input audio signal.

13. A computer-readable medium storing a program for causing a processor to perform a method for processing an audio signal, said method comprising the steps of:

accessing a storage section which stores a set of a plurality of unit information indicative of respective characters of a plurality of unit waves extracted from a time series of character values, representing a character element of an audio signal, in accordance with virtual phases set in the time series, the virtual phases representing phases of a periodic variation of the time series of character values, the unit waves being demarcated from each other cycle by cycle of the periodic variation of the time series of character values, the unit information each including velocity information to be used for control to compress or expand a time length of a corresponding one of the unit waves, and shape information indicative of a shape of a frequency spectrum of the corresponding unit wave;

generating a variation component, corresponding to the time series of character values, from the set of the unit information stored in said storage section; and

imparting the generated variation component to a character element of an input audio signal.