Variable-length code decoding apparatus, decoding system, and variable-length code decoding method
AssigneeKabushiki Kaisha Toshiba
InventorsKojiro Suzuki, Masashi Jobashi
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Abstract
A variable-length code decoding apparatus has a first-table storing part to store a first table, a second-table storing part to store a second table, a priority determining part to read out by priority a combination of zero information that is stored in the second table and corresponds a combination of variable-length codes having the largest number of codes, whereas if variable-length codes included in the input bitstream is not stored in the second table but stored in the first table, to read out zero information, and a decoding part to generate the decoded data based on the zero information or the combination of zero information read out by the priority determining part.
Claims20
A variable-length code decoding apparatus for decoding an input bitstream composed of a plurality of variable-length codes into decoded data composed of nonzeros and zero information expressing a number of successive zeros of 0 or more piece, comprising:
- a first-table storing part configured to store a first table that associates each of the variable-length codes with zero information of a corresponding decoded data;
- a second-table storing part configured to store a second table that associates combinations of a plurality of types of variable-length codes with combinations of zero information of a plurality of types of decoded data;
- a priority determining part configured, if variable-length codes included in the input bitstream and a combination of the variable-length codes are stored in both of the first and second tables, to read out by priority a combination of zero information that is stored in the second table and corresponds a combination of variable-length codes having the largest number of codes, whereas if variable-length codes included in the input bitstream is not stored in the second table but stored in the first table, to read out zero information that is stored in the first table and corresponds to the variable-length codes;
- and
- a decoding part configured to generate the decoded data based on the zero information or the combination of zero information read out by the priority determining part, for each group of a plurality of types of variable-length codes included in the input bitstream.
A decoding system comprising:
- a variable-length code decoding apparatus configured to generate decoded data composed of nonzeros and zeros, the number of the zeros being 0 or more pieces, by performing variable-length code decoding to an input bitstream having variable-length codes made by motion compensation, discrete cosine transform, and quantization;
- an inverse quantization apparatus configured to perform inverse quantization to the decoded data;
- an inverse discrete cosine transforming apparatus configured to perform inverse discrete cosine transform to the inverse-quantized data;
- and
- a motion compensating apparatus configured to perform motion compensation to the data after the inverse discrete cosine transform,
- wherein the variable-length code decoding apparatus includes:
- a first-table storing part configured to store a first table that associates each of the variable-length codes with zero information expressing a number of zero of a corresponding decoded data;
- a second-table storing part configured to store a second table that associates combinations of a plurality of types of variable-length codes with combinations of zero information of a plurality of types of decoded data that correspond to the types of variable-length codes, respectively;
- a priority determining part configured, if variable-length codes included in the input bitstream and a combination of the variable-length codes are stored in both of the first and second tables, to read out by priority a combination of zero information that is stored in the second table and corresponds to a combination of variable-length codes having the largest number of codes, whereas if variable-length codes included in the input bitstream is not stored in the second table but stored in the first table, to read out zero information that is stored in the first table and corresponds to the variable-length codes;
- and
- a decoding part configured to generate the decoded data based on the zero information or the combination of zero information read out by the priority determining part, for each group of a plurality of types of variable-length codes included in the input bitstream.
A variable-length code decoding method for decoding an input bitstream composed of a plurality of variable-length codes into decoded data composed of nonzeros and zeros information expressing a number of successive zeros of 0 or more piece, comprising:
- storing a first table that associates each of the variable-length codes with zero information of a corresponding decoded data;
- storing a second table that associates combinations of a plurality of types of variable-length codes with combinations of zero information of a plurality of types of decoded data;
- if variable-length codes included in the input bitstream and a combination of the variable-length codes are stored in both of the first and second tables, reading out by priority a combination of zero information that is stored in the second table and corresponds to a combination of variable-length codes having the largest number of codes, whereas if variable-length codes included in the input bitstream is not stored in the second table but stored in the first table, reading out zero information that is stored in the first table and corresponds to the variable-length codes;
- and
- generating the decoded data based on the zero information or the combination of zero information read out by the priority determining part, for each group of a plurality of types of variable-length codes included in the input bitstream.
Dependencies are inferred from the claim text.