System and method for compressed domain beat detection in audio bitstreams
First Claim
1. A method for detecting beats in a compression encoded audio bitstream, said method comprising the steps of:
- (a) determining a baseline beat position using modified discrete cosine transform (MDCT) coefficients obtained from the audio bitstream;
(b) deriving from the audio bitstream a window-switching pattern for sub-band sampling windows used to generate the MDCT coefficients;
(c) determining a window-switching beat position based on the derived window-switching pattern;
(d) comparing said baseline beat position with said window-switching beat position; and
(e) validating said window-switching beat position as a detected beat if a predetermined condition is satisfied.
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Abstract
A system and method for detecting beats in a compressed audio domain is disclosed where a beat detector functions as part of an error concealment system in an audio decoding section used in audio information transfer and audio download-streaming system terminal devices such as mobile phones. The beat detector includes a MDCT coefficient extractor, a band feature value analyzer, a confidence score calculator; and a converging and storage unit. The method provides beat detection by means of beat information obtained using both MDCT coefficients as well as window-switching information. A baseline beat position is determined using MDCT coefficients obtained from the audio bitstream which also provides a window-switching pattern. A window-switching beat position is compared with the baseline beat position and, if a predetermined condition is satisfied, the window-switching beat position is validated as a detected beat.
51 Citations
58 Claims
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1. A method for detecting beats in a compression encoded audio bitstream, said method comprising the steps of:
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(a) determining a baseline beat position using modified discrete cosine transform (MDCT) coefficients obtained from the audio bitstream; (b) deriving from the audio bitstream a window-switching pattern for sub-band sampling windows used to generate the MDCT coefficients; (c) determining a window-switching beat position based on the derived window-switching pattern; (d) comparing said baseline beat position with said window-switching beat position; and (e) validating said window-switching beat position as a detected beat if a predetermined condition is satisfied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A beat detector suitable for placement into an audio device conforming to a compression-encoded audio transmission protocol, said beat detector comprising:
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a modified discrete cosine transform coefficient extractor, for obtaining transform coefficients from an audio bitstream; at least one band feature value analyzer for analyzing a feature value for a related band, the at least one band feature value analyzer receiving input from the modified discrete cosine transform coefficient extractor; a confidence score calculator receiving input from the at least one band feature value analyzer, the confidence score calculator calculating a confidence score for beat candidates using stored values of previous inter-onset intervals; and a converging and storage unit for combining two or more of said beat candidates. - View Dependent Claims (27, 28)
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29. An audio encoder suitable for use with a compression-encoded audio transmission protocol, said audio encoder comprising:
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a beat detector including a modified discrete cosine transform coefficient extractor, for obtaining transform coefficients; at least one band feature value analyzer for analyzing a feature value for a related band; a confidence score calculator; and means for including beat detection information as side information in audio transmission.
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30. An audio decoder suitable for use with a compression-encoded audio transmission protocol, said audio decoder comprising:
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a beat detector for providing beat position information, said beat detector including a modified discrete cosine transform coefficient extractor, for obtaining transform coefficients; at least one band feature value analyzer for analyzing a feature value for a related band; a confidence score calculator; and error concealment means for concealing packet loss in audio transmission by utilizing said beat position to identify audio data for replacement of packet loss.
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31. An audio encoder, comprising:
a beat detector, said beat detector being configured to perform a method for detecting beats in a compression encoded audio bitstream, said method including the steps of (a) determining a baseline beat position using modified discrete cosine transform (MDCT) coefficients obtained from the audio bitstream, (b) deriving from the audio bitstream a window-switching pattern for sub-band sampling windows used to generate the MDCT coefficients, (c) determining a window-switching beat position based on the derived window-switching pattern, (d) comparing the baseline beat position with the window-switching beat position, and (e) validating the window-switching beat position as a detected beat if a predetermined condition is satisfied. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. An audio decoder, comprising:
a beat detector, said beat detector being configured to perform a method for detecting beats in a compression encoded audio bitstream, said method including the steps of (a) determining a baseline beat position using modified discrete cosine transform (MDCT) coefficients obtained from the audio bitstream, (b) deriving from the audio bitstream a window-switching pattern for sub-band sampling windows used to generate the MDCT coefficients, (c) determining a window-switching beat position based on the derived window-switching pattern, (d) comparing the baseline beat position with the window-switching beat position, and (e) validating the window-switching beat position as a detected beat if a predetermined condition is satisfied. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58)
Specification