Method and apparatus for synchronizing audio and video components of multimedia presentations by identifying beats in a music signal
First Claim
1. A computer-implemented method of detecting a fundamental beat frequency in a predetermined time interval of a music signal, comprising:
- a) processing a music signal with the discrete wavelet transform to obtain a set of coefficients;
b) processing a subset of the coefficients to obtain a plurality of candidate beat frequencies contained in the corresponding portion of the music signal;
c) determining the harmonic relationships between the candidate beat frequencies;
d) determining the fundamental beat frequency based upon the determined harmonic relationships; and
e) storing information about the determined fundamental beat frequency in a memory for use in production of a multimedia composition.
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Accused Products
Abstract
Methods and systems for detecting a fundamental beat frequency in a predetermined time interval of a music signal are disclosed. The frequency may be detected by processing a music signal with the discrete wavelet transform to obtain a set of coefficients. A subset of the coefficients may be processed to obtain a plurality of candidate beat frequencies contained in the corresponding portion of the music signal. Harmonic relationships between the candidate beat frequencies may be determined, and the fundamental beat frequency may then be determined based upon the determined harmonic relationships.
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Citations
17 Claims
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1. A computer-implemented method of detecting a fundamental beat frequency in a predetermined time interval of a music signal, comprising:
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a) processing a music signal with the discrete wavelet transform to obtain a set of coefficients; b) processing a subset of the coefficients to obtain a plurality of candidate beat frequencies contained in the corresponding portion of the music signal; c) determining the harmonic relationships between the candidate beat frequencies; d) determining the fundamental beat frequency based upon the determined harmonic relationships; and e) storing information about the determined fundamental beat frequency in a memory for use in production of a multimedia composition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for analyzing the beat of a music signal comprising:
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a fundamental beat frequency identifier generating a fundamental beat frequency signal from the music signal; a time domain envelope analyzer comprising a peak generator generating a peak signal from the music signal, the peak signal comprising amplitude and time values of amplitude peaks of the music signal; a comparator and beat identifier, coupled to the fundamental beat frequency identifier and the time domain envelope analyzer, and generating, from the peak signal and fundamental beat frequency signal, a series of time values identifying the amplitude peaks corresponding to onset times of beats within periods based on the fundamental beat frequency signal; and a memory for storing information about the determined fundamental beat frequency for use in production of a multimedia composition. - View Dependent Claims (15, 16)
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11. A computer-implemented method of detecting the localized fundamental beat frequency of a digital music signal comprising:
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detecting time period peaks above a threshold in at least two, consecutive, predetermined-sized buffers of an autocorrelation function of a decomposition of a digital music signal using a discrete wavelet transform; determining which one or more of the detected time period peaks is heard most often in the at least two, consecutive, predetermined-sized buffers, thereby creating a set of “
often-heard”
beat frequencies in a localized portion of the digital music signal and wherein one or more beat frequencies in the set has a magnitude representing how often it is heard;determining the harmonic structure between each beat frequency in the set and the remaining beat frequencies in the set; selecting one of the “
often heard”
beat frequencies as the localized fundamental beat frequency, wherein the criteria for selection comprise the greatest magnitude and a non-ambiguous harmonic structure; andstoring information about the determined fundamental beat frequency in a memory for use in production of a multimedia composition. - View Dependent Claims (12, 13, 14)
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17. A computer-implemented method of identifying beats in a music signal that correspond to a fundamental beat frequency comprising:
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determining a fundamental beat frequency in a music signal using a discrete wavelet transform; obtaining an envelope signal of the music signal, wherein the envelope signal contains amplitude peaks of the music signal that represent beats in the music signal; identifying one or more peaks in the envelope signal as beats in a music signal that correspond to a fundamental beat frequency; and storing information about the determined fundamental beat frequency in a memory for use in production of a multimedia composition.
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Specification