High efficiency encoding or decoding method and device
First Claim
1. A method of encoding, digital information signals of plural channels comprising the steps of:
- allocating to each of the plural channels, from a totality of bits, a respective number of bits as a first bit allocation, each respective first bit allocation based upon an information signal spectrum of a respective channel; and
allocating to at least one of the plural channels, from the totality of bits, an additional number of bits as a second bit allocation, each respective second bit allocation based upon temporal changes of an energy value of the digital information signals in at least one of the plural channels.
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Abstract
A high efficiency encoding method in which pre-set bit allocation is made for digital information signals of plural channels and in which coded information signals are produced by the allocated bits. It is desirable in this type of the high efficiency encoding method to avoid sound quality deterioration produced by pre-echo during abrupt changes in the information signals as well as to suppress the pre-echo to assure aurally desirable bit allocation. To this end, in the high efficiency encoding method, in which digital information signals of plural channels are normalized by normalizing units and pre-set bit allocation is made by a bit allocation unit to effect pre-set bit allocation. The amounts of bit allocation between channels are controlled on the basis of temporal changes of the information signals of the respective channels. Besides, the amounts of bit allocation between channels are controlled based on temporal changes of the amplitude information of digital information signals of the respective channels. At least a part of the bits that may be used for bit allocation is preferentially allocated for channels having larger temporal changes of the information signals depending on the magnitude of temporal changes of the information signals among the plural channels. As a result, deterioration in the sound quality due to pre-echo during high efficiency encoding may be prevented in a system having plural audio signal channels.
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Citations
20 Claims
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1. A method of encoding, digital information signals of plural channels comprising the steps of:
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allocating to each of the plural channels, from a totality of bits, a respective number of bits as a first bit allocation, each respective first bit allocation based upon an information signal spectrum of a respective channel; and allocating to at least one of the plural channels, from the totality of bits, an additional number of bits as a second bit allocation, each respective second bit allocation based upon temporal changes of an energy value of the digital information signals in at least one of the plural channels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A high efficiency decoding method for decoding encoded information signals, comprising the steps of:
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separately decoding the encoded information signals for each of the plural channels using respective block size information and respective bit allocation information for each of the plural channels to output frequency domain signals, the encoded information signals obtained on the basis of allocated bits, wherein from a totality of bits a pre-set bit allocation is made for digital information signals of plural channels, and wherein an additional bit allocation among the channels is based on temporal changes of an energy value of the information signals of at least one of the respective channels; and orthogonally transforming the frequency domain signals into time-domain signals.
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19. A high efficiency decoding device for decoding encoded information signals obtained on the basis of allocated bits, where a pre-set bit allocation is made for digital information signals of plural channels, wherein the bit allocation among the channels is based on temporal changes of an energy value of the information signals of the respective channels, comprising:
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means for separately decoding the encoded information signals for each of the plural channels using respective block size information and respective bit allocation information for each of the plural channels to output frequency domain signals, the encoded information signals obtained on the basis of allocated bits, wherein from a totality of bits a pre-set bit allocation is made for digital information signals of plural channels, and wherein an additional bit allocation among the channels is based on temporal changes of an energy value of the information signals of at least one of the respective channels; and means for orthogonally transforming the frequency domain signals into time-domain signals.
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20. A high efficiency decoding device for decoding encoded information signals, comprising:
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a plurality of decoders for separately decoding the encoded information signals for each of the plural channels using respective block size information and respective bit allocation information for each of the plural channels to output frequency domain signals, the encoded information signals obtained on the basis of allocated bits, wherein from a totality of bits a pre-set bit allocation is made for digital information signals of plural channels, and wherein an additional bit allocation among the channels is based on temporal changes of an energy value of the information signals of at least one of the respective channels; and a plurality of orthogonal transformers for orthogonally transforming the frequency domain signals into time-domain signals.
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Specification