Encoding method and apparatus, and decoding method and apparatus
First Claim
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1. An encoding method of an encoder, the method comprising:
- transforming an input signal to generate first modified discrete cosine transform (MDCT) coefficients;
quantizing the first MDCT coefficients to generate MDCT indices;
dequantizing the MDCT indices to generate second MDCT coefficients;
computing MDCT residual coefficients using differences between the first MDCT coefficients and the second MDCT coefficients;
encoding the MDCT residual coefficients to generate a residual index;
generating gain indices corresponding to gains from the first MDCT coefficients and the second MDCT coefficients; and
multiplexing the MDCT indices, the residual index, and the gain indices by a multiplexer to generate a bit stream,wherein generating the residual index comprises selecting an index of a sub-band with a largest energy of MDCT residual coefficients among a plurality of sub-bands, andwherein encoding the MDCT residual coefficients comprises selecting a pulse at a position corresponding to a predetermined number of MDCT residual coefficients, and generating the gain indices comprises computing exponents that are logarithms of magnitudes of the second MDCT coefficients at positions excluding the position of the pulse.
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Abstract
An encoding method of an encoder is provided. The encoder generates first MDCT coefficients by transforming an input signal, and generates MDCT indices by quantizing the first MDCT coefficients. The encoder generates second MDCT coefficients by dequantizing the MDCT indices, and calculates MDCT residual coefficients using differences between the first MDCT coefficients and the second MDCT coefficients. The encoder generates a residual index by encoding the MDCT residual coefficients, and generates gain indices corresponding to gains from the first MDCT coefficients and the second MDCT coefficients.
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Citations
34 Claims
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1. An encoding method of an encoder, the method comprising:
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transforming an input signal to generate first modified discrete cosine transform (MDCT) coefficients; quantizing the first MDCT coefficients to generate MDCT indices; dequantizing the MDCT indices to generate second MDCT coefficients; computing MDCT residual coefficients using differences between the first MDCT coefficients and the second MDCT coefficients; encoding the MDCT residual coefficients to generate a residual index; generating gain indices corresponding to gains from the first MDCT coefficients and the second MDCT coefficients; and multiplexing the MDCT indices, the residual index, and the gain indices by a multiplexer to generate a bit stream, wherein generating the residual index comprises selecting an index of a sub-band with a largest energy of MDCT residual coefficients among a plurality of sub-bands, and wherein encoding the MDCT residual coefficients comprises selecting a pulse at a position corresponding to a predetermined number of MDCT residual coefficients, and generating the gain indices comprises computing exponents that are logarithms of magnitudes of the second MDCT coefficients at positions excluding the position of the pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A decoding method of a decoder, the method comprising:
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demultiplexing a received bit stream by a demultiplexer to receive MDCT indices, a residual index, and gain indices; dequantizing the MDCT indices to generate first MDCT coefficients; decoding the residual index to recover MDCT residual coefficients; recovering gains from the gain indices using a position of a pulse at a position corresponding to the MDCT residual coefficients and the first MDCT coefficients; compensating gains of the first MDCT coefficients with the recovered gains generating second MDCT coefficients; and compensating residuals of the second MDCT coefficients with the MDCT residual coefficients, wherein recovering the gains comprises computing exponents that are logarithms of magnitudes of the first MDCT coefficients at positions excluding the position of the pulse. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An encoding apparatus, comprising:
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an MDCT configured to transform an input signal to generate first MDCT coefficients; an MDCT quantizer configured to quantize the first MDCT coefficients to generate MDCT indices; an enhancement layer encoder configured to dequantize the MDCT indices to generate second MDCT coefficients, to encode MDCT residual coefficients corresponding to differences between the first MDCT coefficients and the second MDCT coefficients to generate a residual index, and to generate gain indices corresponding to gains of the first MDCT coefficients from the first MDCT coefficients and the second MDCT coefficients; and a multiplexer configured to multiplex the MDCT indices, the residual index, and the gain indices to generate a bit stream, wherein the enhancement layer encoder comprises a residual compensation encoder configured to select an index of a sub-band having a largest energy of MDCT residual coefficients among a plurality of sub-bands, and wherein the residual compensation encoder selects a pulse at a position corresponding to a predetermined number of MDCT residual coefficients, and the enhancement layer encoder generates exponents that are logarithms of magnitudes of the second MDCT coefficients at positions excluding the position of the pulse. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A decoding apparatus, comprising:
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a demultiplexer configured to demultiplex a received bit stream to output MDCT indices, a residual index, and gain indices; an MDCT dequantizer configured to dequantize the MDCT indices to generate first MDCT coefficients; and an enhancement layer decoder configured to decode the residual index, recover gains from the gain indices using a position of a pulse at a position corresponding to the MDCT residual coefficients and the first MDCT coefficients to recover MDCT residual coefficients, compensate gains of the first MDCT coefficients with the recovered gains to generate second MDCT coefficients, and compensate residuals of the second MDCT coefficients with the MDCT residual coefficients, wherein the enhancement layer decoder comprises a gain compensation decoder configured to compute exponents that are logarithms of magnitudes of the first MDCT coefficients at positions excluding the position of the pulse. - View Dependent Claims (30, 31, 32, 33, 34)
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Specification