Encoding device and method, decoding device and method, and program
First Claim
1. An encoding device comprising;
- subband dividing means configured to divide an input signal into a plurality of subbands, and to generate a low-frequency subband signal including a plurality of subbands on the low-frequency side, and a high-frequency subband signal including a plurality of subbands on the high-frequency side;
feature amount calculating means configured to calculate feature amount that represents features of the input signal based on at least any one of the low-frequency subband signal and the input signal;
smoothing means configured to subject the feature amount to smoothing;
pseudo high-frequency subband power calculating means configured to calculate pseudo high-frequency subband power that is an estimated value of power of the high-frequency subband signal based on the smoothed feature amount and a predetermined coefficient;
selecting means configured to calculate high-frequency subband power of the high-frequency subband signal from the high-frequency subband signal, and to compare the high-frequency subband power and the pseudo high-frequency subband power to select a coefficient from a plurality of coefficients;
high-frequency encoding means configured to encode coefficient information for obtaining the selected coefficient, and smoothing information relating to the smoothing to generate high-frequency encoded data;
low-frequency encoding means configured to encode a low-frequency signal of the input signal to generate low-frequency encoded data; and
multiplexing means configured to multiplex the low-frequency encoded data and the high-frequency encoded data to obtain an output code string for transmitting to a playback device including a decoding device.
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Abstract
The present invention relates to an encoding device and method, and a decoding device and method, and a program which enable music signals to be played with higher sound quality by expanding a frequency band.
A band pass filter divides an input signal into multiple subband signals, a feature amount calculating circuit calculates feature amount using at least any one of the divided multiple subband signals and the input signal, a high-frequency subband power estimating circuit calculates an estimated value of high-frequency subband power based on the calculated feature amount, and a high-frequency signal generating circuit generates a high-frequency signal component based on the multiple subband signals divided by the band pass filter and the estimated value of the high-frequency subband power calculated by the high-frequency subband power estimating circuit. A frequency band expanding device expands the frequency band of the input signal using the high-frequency signal component generated by the high-frequency signal generating circuit. The present invention may be applied to a frequency band expanding device, encoding device, decoding device, and so forth, for example.
31 Citations
20 Claims
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1. An encoding device comprising;
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subband dividing means configured to divide an input signal into a plurality of subbands, and to generate a low-frequency subband signal including a plurality of subbands on the low-frequency side, and a high-frequency subband signal including a plurality of subbands on the high-frequency side; feature amount calculating means configured to calculate feature amount that represents features of the input signal based on at least any one of the low-frequency subband signal and the input signal; smoothing means configured to subject the feature amount to smoothing; pseudo high-frequency subband power calculating means configured to calculate pseudo high-frequency subband power that is an estimated value of power of the high-frequency subband signal based on the smoothed feature amount and a predetermined coefficient; selecting means configured to calculate high-frequency subband power of the high-frequency subband signal from the high-frequency subband signal, and to compare the high-frequency subband power and the pseudo high-frequency subband power to select a coefficient from a plurality of coefficients; high-frequency encoding means configured to encode coefficient information for obtaining the selected coefficient, and smoothing information relating to the smoothing to generate high-frequency encoded data; low-frequency encoding means configured to encode a low-frequency signal of the input signal to generate low-frequency encoded data; and multiplexing means configured to multiplex the low-frequency encoded data and the high-frequency encoded data to obtain an output code string for transmitting to a playback device including a decoding device. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An encoding method comprising the steps of:
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dividing an input signal into a plurality of subbands, and generating a low-frequency subband signal including a plurality of subbands on the low-frequency side, and a high-frequency subband signal including a plurality of subbands on the high-frequency side; calculating feature amount that represents features of the input signal based on at least one of the low-frequency subband signal and the input signal; subjecting the feature amount to smoothing; calculating pseudo high-frequency subband power that is an estimated value of power of the high-frequency subband signal based on the smoothed feature amount and a predetermined coefficient; calculating high-frequency subband power of the high-frequency subband signal from the high-frequency subband signal, and comparing the high-frequency subband power and the pseudo high-frequency subband power to select a coefficient from a plurality of coefficients; encoding coefficient information for obtaining the selected coefficient, and smoothing information relating to the smoothing to generate high-frequency encoded data; encoding a low-frequency signal of the input signal to generate low-frequency encoded data; and multiplexing the low-frequency encoded data and the high-frequency encoded data to obtain an output code string for transmitting to a playback device including a decoding device.
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8. A non-transitory computer-readable medium encoded with a program that, when executed by a computer, causes the computer to execute processing comprising the steps of:
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dividing an input signal into a plurality of subbands, and generating a low-frequency subband signal made up of a plurality of subbands on the low-frequency side, and a high-frequency subband signal made up of a plurality of subbands on the high-frequency side; calculating feature amount that represents features of the input signal based on at least any one of the low-frequency subband signal and the input signal; subjecting the feature amount smoothing; calculating pseudo high-frequency subband power that is an estimated value of power of the high-frequency subband signal based on the smoothed feature amount and a predetermined coefficient; calculating high-frequency subband power of the high-frequency subband signal from the high-frequency subband signal, and comparing the high-frequency subband power and the pseudo high-frequency subband power to select any of a plurality of the coefficients; encoding coefficient information for obtaining the selected coefficient, and smoothing information relating to the smoothing to generate high-frequency encoded data; encoding a low-frequency signal of the input signal to generate low-frequency encoded data; and multiplexing the low-frequency encoded data and the high-frequency encoded data to obtain an output code string for transmitting to a playback device including a decoding device.
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9. A decoding device comprising:
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demultiplexing means configured to demultiplex input encoded data into low-frequency encoded data, coefficient information for obtaining a coefficient, and smoothing information relating to smoothing; low-frequency decoding means configured to decode the low-frequency encoded data to generate a low-frequency signal; subband dividing means configured to divide the low-frequency signal into a plurality of subbands to generate a low-frequency subband signal for each of the subbands; feature amount calculating means configured to calculate feature amount based on the low-frequency subband signals; smoothing means configured to subject the feature amount to smoothing based on the smoothing information; and generating means configured to generate a high-frequency signal based on the coefficient obtained from the coefficient information, the feature amount subjected to smoothing, and the low-frequency subband signals, wherein the low-frequency signal and the high frequency signal produce high sound quality when combined and played back. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A decoding method comprising the steps of:
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demultiplexing input encoded data into low-frequency encoded data, coefficient information for obtaining a coefficient, and smoothing information relating to smoothing; decoding the low-frequency encoded data to generate a low-frequency signal; dividing the low-frequency signal into a plurality of subbands to generate a low-frequency subband signal for each of the subbands; calculating feature amount based on the low-frequency subband signals; subjecting the feature amount to smoothing based on the smoothing information; and generating a high-frequency signal based on the coefficient obtained from the coefficient information, the feature amount subjected to smoothing, and the low-frequency subband signals, wherein the low-frequency signal and the high-frequency signal produce high sound quality when combined and played back.
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16. A non-transitory computer-readable medium encoded with a program that, when executed by a computer, causes the computer to execute processing comprising the steps of:
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demultiplexing input encoded data into low-frequency encoded data, coefficient information for obtaining a coefficient, and smoothing information relating to smoothing; decoding the low-frequency encoded data to generate a low-frequency signal; dividing the low-frequency signal into a plurality of subbands to generate a low-frequency subband signal for each of the subbands; calculating feature amount based on the low-frequency subband signals; subjecting the feature amount to smoothing based on the smoothing information; and generating a high-frequency signal based on the coefficient obtained from the coefficient information, the feature amount subjected to smoothing, and the low-frequency subband signals, wherein the low-frequency signal and the high-frequency signal produce high sound quality when combined and played back.
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17. An encoding device comprising:
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a subband dividing circuit configured to divide an input signal into a plurality of subbands, and to generate a low-frequency subband signal including a plurality of subbands on the low-frequency side, and a high-frequency subband signal including, a plurality of subbands on the high-frequency side; a feature amount calculating circuit configured to calculate feature amount that represents features of the input signal based on at least any one of the low-frequency subband signal and the input signal; a smoothing circuit configured to subject the feature amount to smoothing; a pseudo high-frequency subband power calculating circuit configured to calculate pseudo high-frequency subband power that is an estimated value of power of the high-frequency subband signal based on the smoothed feature amount and a predetermined coefficient; a selecting circuit configured to calculate high-frequency subband power of the high-frequency subband signal from the high-frequency subband signal, and to compare the high-frequency subband power and the pseudo high-frequency subband power to select a coefficient from a plurality of coefficients; a high-frequency encoding circuit configured to encode coefficient information for obtaining the selected coefficient, and smoothing information relating to the smoothing to generate high-frequency encoded data; a low-frequency encoding circuit configured to encode a low-frequency signal of the input signal to generate low-frequency encoded data; and a multiplexing circuit configured to multiplex the low-frequency encoded data and the high-frequency encoded data to obtain an output code string for transmitting to a playback device including a decoding device. - View Dependent Claims (18)
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19. A decoding device comprising:
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a demultiplexing circuit configured to demultiplex input encoded data into low-frequency encoded data, coefficient information for obtaining a coefficient, and smoothing information relating to smoothing; a low-frequency decoding circuit configured to decode the low-frequency encoded data to generate a low-frequency signal; a subband dividing circuit configured to divide the low-frequency signal into a plurality of subbands to generate a low-frequency subband signal for each of the subbands; a feature amount calculating circuit configured to calculate feature amount based on the low-frequency subband signals; a smoothing circuit configured to subject the feature amount to smoothing based on the smoothing information; and a generating circuit configured to generate a high-frequency signal based on the coefficient obtained from the coefficient information, the feature amount subjected to smoothing, and the low-frequency subband signals, wherein the low-frequency signal and the high-frequency signal produce high sound quality when combined and played back. - View Dependent Claims (20)
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Specification