Video signal encoding method and apparatus employing an adaptive quantization technique
First Claim
1. A method for encoding a video signal including a quantization-dependent signal and a quantization-independent signal, comprising the steps of:
- (a) quantizing the quantization-dependent signal base on a fixed quantization parameter to thereby generate first quantized data;
(b) statistically coding the first quantized data and the quantization-independent signal to thereby provide first data and second data, respectively;
(c) storing the amount of the first data and the amount of the second data;
(d) determining a target amount of encoded bits for each of predetermined units of the video signal based on a predetermined target bit rate and the stored amounts of the first and the second data;
(e) deciding one or more quantization parameters for each unit based on the target amount of encoded bits;
(f) quantizing the quantization-dependent data based on the decided quantization parameters to thereby generate second quantized data; and
(g) statistically coding the second quantized data and the quantization-independent signal to thereby generate third data and fourth data, respectively, as the encoded data of the video signal,wherein the quantization parameters are adaptively decided in response to the difference between the target amount of encoded bits and the amount of the encoded data.
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Abstract
A method employed in an encoding apparatus allocates bits for each of the pictures and blocks of a video signal based on quantization-dependent and quantization-independent signal thereof. First, the quantization-dependent signal is quantized based on a fixed quantization parameter; and the quantized data and the quantization-independent signal are statistically coded to thereby provided first data and second data. A target amount of encoded bits for each picture and block is then determined based on a target bit rate and the respective amounts of the first and the second data. The amounts of encoded data for the pictures and the blocks are adaptively controlled according to the target amounts of encoded bits by adjustably altering quantization parameters based on the difference between the target amount of the encoded bits and the amount of the encoded data generated.
52 Citations
18 Claims
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1. A method for encoding a video signal including a quantization-dependent signal and a quantization-independent signal, comprising the steps of:
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(a) quantizing the quantization-dependent signal base on a fixed quantization parameter to thereby generate first quantized data; (b) statistically coding the first quantized data and the quantization-independent signal to thereby provide first data and second data, respectively; (c) storing the amount of the first data and the amount of the second data; (d) determining a target amount of encoded bits for each of predetermined units of the video signal based on a predetermined target bit rate and the stored amounts of the first and the second data; (e) deciding one or more quantization parameters for each unit based on the target amount of encoded bits; (f) quantizing the quantization-dependent data based on the decided quantization parameters to thereby generate second quantized data; and (g) statistically coding the second quantized data and the quantization-independent signal to thereby generate third data and fourth data, respectively, as the encoded data of the video signal, wherein the quantization parameters are adaptively decided in response to the difference between the target amount of encoded bits and the amount of the encoded data. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for encoding a video signal including a quantization-dependent signal and a quantization-independent signal, comprising:
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first encoding means having; a first quantization means for quantizing the quantization-dependent signal based on a fixed quantization parameter to thereby generate first quantized data, a first statistical coder for coding the first quantized data and the quantization-independent signal to thereby provide first data and second data, respectively, and a first counting means for finding the amount of the first data and the amount of the second data; means for storing the respective amounts of the first and the second data; and a second encoding means having; means for determining a target amount of encoded bits for each of predetermined units of the video signal, means for deriving one or more quantization parameter for each unit based on the target amount of encoded bits, a second quantization means for quantizing the quantization-dependent signal based on the decided quantization parameters to thereby generate second quantized data, a second statistical coder for coding the second quantized data and the quantization-independent signal to thereby generate third data and fourth data, respectively, as encoded data of the video signal, and a second counting means for determining the amount of the third data and the amount of the fourth data. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An apparatus for encoding a video signal which includes a quantization-dependent signal and a quantization-independent signal, comprising:
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means for quantizing the quantization-dependent signal to thereby provide first quantized data; means for statistically coding the first quantized data and the quantization-independent signal, thereby generating first data and second data, respectively; a counting means for obtaining the amount of the first data and the amount of the second data; means for storing the amount of the first data and the amount of the second data; a target bits determination means for determining a target amount of encoded bits for each of predetermined units of video signal based on a target bit rate and the stored amounts of the first and the second data; a bit control means for deciding an initial quantization parameter based on the target amount of encoded bits and deciding further quantization parameters based on a difference between the target amount of encoded bits and the amount of the encoded data generated by the statistically coding means to thereby generate decided quantization parameters; means for setting a fixed quantization parameter; and controlling means for coupling the fixed quantization parameter to the quantizing means and inputting the amounts of first and second data to the storing means and, thereafter, providing the stored amounts of first and second data, the outputs of the counting means and the decided quantization parameters to the target bits determination means, the bit control means and the quantizing means, respectively, thereby adaptively controlling quantization step sizes at the quantizing means. - View Dependent Claims (16, 17, 18)
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Specification