Audio reproducing apparatus
First Claim
1. An audio reproducing apparatus comprising:
- audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
a frame sequence table which contains a sequence determined according to a given speed rate in which respective frames are to be expanded/compressed;
frame counting means for counting the number of frames of the input audio signal; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, with reference to the frame sequence table based on a count value output from the frame counting means, the data expanding/compressing means subjecting the audio signal to time-scale modification process in accordance with an instruction signal from the data expansion/compression control means.
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Abstract
An audio reproducing apparatus comprises: audio decoding means for decoding an input audio signal frame by frame; data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process; a frame sequence table which contains a sequence determined according to a given speed rate in which respective frames are expanded/compressed; frame counting means for counting the number of frames of the input audio signal; and data expansion/compression control means for instructing the dalta expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, with reference to the frame sequence table based on a count value output from the frame counting means, the data expanding/compressing means subjecting the audio signal to time-scale modification process in accordance with an instruction signal from the data expansion/compression control means.
80 Citations
58 Claims
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1. An audio reproducing apparatus comprising:
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audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
a frame sequence table which contains a sequence determined according to a given speed rate in which respective frames are to be expanded/compressed;
frame counting means for counting the number of frames of the input audio signal; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, with reference to the frame sequence table based on a count value output from the frame counting means, the data expanding/compressing means subjecting the audio signal to time-scale modification process in accordance with an instruction signal from the data expansion/compression control means. - 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)
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
5. The audio reproducing apparatus of claim 1 wherein the data expanding/compressing means subjects a frame to time-scale compression/expansion process in a prescribed ratio, and the data expansion/compression control means controls frequency at which frames to be subjected to time-scale compression/expansion process and frames to be output without time-scale modification process appear, to reproduce audio at the given speed rate.
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6. The audio reproducing apparatus of claim 5 wherein the data expanding/compressing means subjects the frame to time-scale compression/expansion process in a prescribed ratio, and the frame sequence table contains the sequence in which frames to be subjected to time-scale compression/expansion process in the frame cycle in which a time-scale compression/expansion sequence is repeated are disposed as uniformly as possible, to reproduce audio at the given speed rate.
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7. The audio reproducing apparatus of claim 6 wherein the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of divided subbands.
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8. The audio reproducing apparatus of claim 6 wherein the audio decoding means for performing decoding frame by frame decodes data coded by an MPEG1 audio layer 2 coding method.
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9. The audio reproducing apparatus of claim 6 wherein the data expanding/compressing means includes correlation calculating means for calculating correlation between segments of a frame and a position at which the correlation is high, and sending shift amount by which waveform data of a segment is shifted to the position,
the cross fading means shifts the waveform data of the segment according to the shift amount, and performs weighting addition to each segment data, and for a subsequent frame to be subjected to time-scale compression/expansion, segment data is shifted and subjected to weighting addition, considering the shift amount of a frame which has been previously subjected to time-scale compression/expansion. -
10. The audio reproducing apparatus of claim 9 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, the correlation calculating means calculates a correlation value for each subband, and weighting addition is performed by using the shift amount of a subband which has the largest correlation value. -
11. The audio reproducing apparatus of claim 9 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means calculates a correlation value for a subband of the divided subbands which has the highest averaged energy. -
12. The audio reproducing apparatus of claim 6 wherein
the data expanding/compressing means includes correlation calculating means for finding correlation between segments in each frame, the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means finds correlation between the segments by the use of data of a subband which contains pitch frequency of an audio signal. -
13. The audio reproducing apparatus of claim 3 wherein
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
14. The audio reproducing apparatus of claim 5 wherein
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
15. The audio reproducing apparatus of claim 1 wherein the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of divided subbands.
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16. The audio reproducing apparatus of claim 1 wherein the audio decoding means for performing decoding frame by frame decodes data coded by an MPEG1 audio layer 2 coding method.
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17. The audio reproducing apparatus of claim 1 wherein
the data expanding/compressing means includes correlation calculating means for calculating correlation between segments of a frame and a position at which the correlation is high, and sending shift amount by which waveform data of a segment is shifted to the position, the cross fading means shifts the waveform data of the segment according to the shift amount, and performs weighting addition to each segment data, and for a subsequent frame to be subjected to time-scale compression/expansion, segment data is shifted and subjected to weighting addition, considering the shift amount of a frame which has been previously subjected to time-scale compression/expansion. -
18. The audio reproducing apparatus of claim 17 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, the correlation calculating means calculates a correlation value for each subband, and weighting addition is performed by using the shift amount of a subband which has the largest correlation value. -
19. The audio reproducing apparatus of claim 18 wherein
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
20. The audio reproducing apparatus of claim 17 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means calculates a correlation value of a subband of the divided subbands which has the highest averaged energy. -
21. The audio reproducing apparatus of claim 20
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
22. The audio reproducing apparatus of claim 17 wherein
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
23. The audio reproducing apparatus of claim 1 wherein
the data expanding/compressing means includes correlation calculating means for finding correlation between segments in each frame; -
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of divided subbands, and the correlation calculating means finds correlation between the segments by the use of data of a subband which contains pitch frequency of an audio signal.
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24. The audio reproducing apparatus of claim 23 wherein
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest. -
25. The audio reproducing apparatus of claim 1 wherein
the frame sequence table includes plural sequence tables having different patterns per one speed rate, the data expanding/compressing means finds an average of correlation values between segments in respective frames to be expanded/compressed for each sequence table, and performs processing with reference to a sequence table in which the average is the largest.
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26. An audio reproducing apparatus comprising:
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audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
expansion/compression frequency control means for setting a frame cycle number and the number of frames to be expanded/compressed in the frame cycle, according to a given speed rate;
energy calculating means for calculating energies of audio signals in respective frames;
frame selecting means for selecting frames to be expanded/compressed according to an output of the energy calculating means and an output of the expansion/compression frequency control means; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, the frame selecting means selecting low-energy frames with priority. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33)
the data expanding/compressing means includes correlation calculating means for calculating correlation between segments of a frame and a position at which the correlation is high, and sending shift amount by which waveform data of a segment is shifted to the position, the cross fading means shifts the waveform data of the. segment according to the shift amount, and performs weighting addition to each segment data, and for a subsequent frame to be subjected to time-scale compression/expansion process, segment data is shifted and subjected to weighting addition, considering the shift amount of a frame which has been previously subjected to time-scale compression/expansion process. -
31. The audio reproducing apparatus of claim 30 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, the correlation calculating means calculates a correlation value for each subband, and weighting addition is performed by using the shift amount of a subband which has the largest correlation value. -
32. The audio reproducing apparatus of claim 30 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means calculates a correlation value for a subband of the divided subbands which has the highest averaged energy. -
33. The audio reproducing apparatus of claim 26 wherein
the data expanding/compressing means includes correlation calculating means for finding correlation between segments in each frame, the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means finds correlation between the segments by the use of data of a subband which contains pitch frequency of an audio signal.
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34. An audio reproducing apparatus comprising:
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audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
expansion/compression frequency control means for setting a frame cycle number and the number of frames to be expanded/compressed in the frame cycle, according to a given speed rate;
means for calculating probabilities that respective frames contain humane voice;
frame selecting means for selecting frames to be expanded/compressed according to an output of the means for calculating probabilities and an output of the expansion/compression frequency control means; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, the frame selecting means selecting low-probability frames with priority. - View Dependent Claims (35, 36, 37, 38, 39, 40)
the data expanding/compressing means includes correlation calculating means for calculating correlation between segments of a frame and a position at which the correlation is high, and sending shift amount by which waveform data of a segment is shifted to the position, the cross fading means shifts the waveform data of the segment according to the shift amount, and performs weighting addition to each segment data, and for a subsequent frame to be subjected to time-scale compression/expansion process, segment data is shifted and subjected to weighting addition, considering the shift amount of a frame which has been previously subjected to time-scale compression/expansion process. -
38. The audio reproducing apparatus of claim 37 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, the correlation calculating means calculates a correlation value for each subband, and weighting addition is performed by using the shift amount of a subband which has the largest correlation value. -
39. The audio reproducing apparatus of claim 37 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means calculates a correlation value for a subband of the divided subbands which has the highest averaged value. -
40. The audio reproducing apparatus of claim 34 wherein
the data expanding/compressing means includes correlation calculating means for finding correlation between segments in each frame, the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means finds correlation between the segments by the use of data of a subband which contains pitch frequency of an audio signal.
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41. An audio reproducing apparatus comprising:
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audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
expansion/compression frequency control means for setting a frame cycle number and the number of frames to be expanded/compressed in the frame cycle, according to a given speed rate;
stationarity calculating means for calculating stationarities of audio signals in respective frames;
frame selecting means for selecting frames to be expanded/compressed according to an output of the stationarity calculating means and an output of the expansion/compression frequency control means; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, the frame selecting means selecting high-stationarity frames with priority. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
the cross fading means shifts the waveform data of the segment according to the shift amount, and performs weighting addition to each segment data, and for a subsequent frame to be subjected to time-scale compression/expansion process, segment data is shifted and subjected to weighting addition, considering the shift amount of a frame which has been previously subjected to time-scale compression/expansion process. -
46. The audio reproducing apparatus of claim 45 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, the correlation calculating means calculates a correlation value for each subband, and weighting addition is performed by using the shift amount of a subband which has the largest correlation value. -
47. The audio reproducing apparatus of claim 45 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means calculates a correlation value for a subband of the divided subbands which has the highest averaged energy. -
48. The audio reproducing apparatus of claim 41 wherein
the data expanding/compressing means includes correlation calculating means for finding correlation between segments in each frame, the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means finds correlation between the segments by the use of data of a subband which contains pitch frequency of an audio signal.
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49. An audio reproducing apparatus comprising:
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audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
expansion/compression frequency control means for setting a frame cycle number and the number of frames to be expanded/compressed in the frame cycle, according to a given speed rate;
means for calculating degrees of energy change of audio signals in respective frames;
frame selecting means for selecting frames to be expanded/compressed according to an output of the means for calculating degrees of energy change and an output of the expansion/compression frequency control means; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, the frame selecting means selecting frames with priority in which distortion is hardly detected because of masking effects, according to the degrees of energy change. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56)
the data expanding/compressing means includes correlation calculating means for calculating correlation between segments of a frame and a position at which the correlation is high, and sending shift amount by which waveform data of a segment is shifted to the position, the cross fading means shifts the waveform data of the segment according to the shift amount, and performs weighting addition to each segment data, and for a subsequent frame to be subjected to time-scale compression/expansion process, segment data is shifted and subjected to weighting addition, considering the shift amount of a frame which has been previously subjected to time-scale compression/expansion process. -
54. The audio reproducing apparatus of claim 53 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, the correlation calculating means calculates a correlation value for each subband, and weighting addition is performed by using the shift amount of a subband which has the largest correlation value. -
55. The audio reproducing apparatus of claim 53 wherein
the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means calculates a correlation value for a subband of the divided subbands which has the highest averaged energy. -
56. The audio reproducing apparatus of claim 49 wherein
the data expanding/compressing means includes correlation calculating means for finding correlation between segments in each frame, the audio decoding means for performing decoding frame by frame divides an audio signal into plural subband signals and performs decoding for each of the divided subbands, and the correlation calculating means finds correlation between the segments by the use of data of a subband which contains pitch frequency of an audio signal.
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57. An audio reproducing apparatus comprising:
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audio decoding means for decoding an input audio signal frame by frame;
data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process;
expansion/compression frequency control means for setting a frame cycle number and the number of frames to be expanded/compressed in the frame cycle, according to a given speed rate;
at least two of energy calculating means for calculating energies of audio signals in respective frames, means for calculating probabilities that respective frames contain humane voice, stationarity calculating means for calculating stationarities of audio signals in respective frames, and means for calculating degrees of energy change of audio signals in respective frames;
frame selecting means for selecting frames to be expanded/compressed according to outputs of plural calculating means and an output of the expansion/compression frequency control means; and
data expansion/compression control means for instructing the data expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, the frame selecting means deciding frames to be selected according to the outputs of the plural calculating means. - View Dependent Claims (58)
the audio decoding means for performing decoding frame by frame decodes data coded by an MPEG1 audio layer 2 coding method, further comprising: at least two of the energy calculating means, stationarity calculating means, and the means for calculating degrees of energy change wherein, the energy calculating means estimates an energy of an audio signal based on a scalefactor index indicating a scalefactor at reproduction, the stationarity calculating means estimates a stationarity of an audio signal based on scalefactor selection information indicating waveform stationarity, and the means for calculating degrees of energy change estimates a degree of energy change of an audio signal based on a scalefactor index indicating a scalefactor at reproduction.
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Specification