METHOD AND APPARATUS FOR ADAPTIVELY DETERMINING QUANTIZATION STEP ACCORDING TO MASKING EFFECT IN PSYCHOACOUSTICS MODEL AND ENCODING/DECODING AUDIO SIGNAL BY USING DETERMINED QUANTIZATION STEP
First Claim
1. A method of adaptively determining a quantization step according to a masking effect in a psychoacoustics model, the method comprising:
- calculating a first ratio value indicating an intensity of an input audio signal with respect to a masking threshold; and
determining a maximum value of the quantization step in a range in which noise generated when the audio signal is quantized, is masked, according to the first ratio value.
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Abstract
Provided are a method of adaptively determining a quantization step according to a masking effect in a psychoacoustics model and a method of encoding/decoding an audio signal by using the determined quantization step. The method of adaptively determining a quantization step includes calculating a first ratio value indicating an intensity of an input audio signal with respect to a masking threshold; and determining the maximum value of the quantization step in a range in which noise generated when the audio signal is quantized is masked, according to the first ratio value. According to the present invention, quantization noise may be removed and the number of bits required to encode an audio signal may be reduced, by using auditory characteristics of humans.
44 Citations
19 Claims
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1. A method of adaptively determining a quantization step according to a masking effect in a psychoacoustics model, the method comprising:
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calculating a first ratio value indicating an intensity of an input audio signal with respect to a masking threshold; and determining a maximum value of the quantization step in a range in which noise generated when the audio signal is quantized, is masked, according to the first ratio value. - View Dependent Claims (2, 3, 4, 5)
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6. A method of encoding an audio signal based on a quantization step adaptively determined according to a masking effect in a psychoacoustics model, the method comprising:
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calculating a first ratio value indicating an intensity of the audio signal with respect to a masking threshold; determining a maximum value of the quantization step in a range in which noise generated when the audio signal is quantized, is masked, according to the first ratio value; quantizing the audio signal based on the determined maximum value of the quantization step; and generating a variable length encoded bitstream based on the quantized audio signal. - View Dependent Claims (7, 8, 9, 10)
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11. A method of decoding an audio signal based on a dequantization step adaptively determined according to a masking effect in a psychoacoustics model, the method comprising:
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variable length decoding the audio signal input in a form of a bitstream; calculating a first ratio value indicating an intensity of the variable length decoded audio signal with respect to a masking threshold; determining a maximum value of the dequantization step in a range in which noise generated when the audio signal is quantized, is masked, according to the first ratio value; and dequantizing the audio signal based on the determined maximum value of the dequantization step. - View Dependent Claims (12, 13, 14, 15)
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16. An apparatus for encoding an audio signal based on a quantization step adaptively determined according to a masking effect in a psychoacoustics model, the apparatus comprising:
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a first ratio value calculation unit which calculates a first ratio value indicating an intensity of the audio signal with respect to a masking threshold; a quantization step determination unit which determines a maximum value of the quantization step in a range in which noise generated when the audio signal is quantized, is masked, according to the first ratio value; a quantization unit which quantizes the audio signal based on the determined maximum value of the quantization step; and a variable length encoding unit which generates a variable length encoded bitstream based on the quantized audio signal. - View Dependent Claims (17)
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18. An apparatus for decoding an audio signal based on a dequantization step adaptively determined according to a masking effect in a psychoacoustics model, the apparatus comprising:
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a variable length decoding unit which variable length decodes the audio signal input in a form of a bitstream; a first ratio value calculation unit which calculates a first ratio value indicating an intensity of the variable length decoded audio signal with respect to a masking threshold; a dequantization step determination unit which determines a maximum value of the dequantization step in a range in which noise generated when the audio signal is quantized, is masked, according to the first ratio value; and a dequantization unit which dequantizes the audio signal based on the determined maximum value of the dequantization step. - View Dependent Claims (19)
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Specification