Moving picture coding and/or decoding systems, and variable-length coding and/or decoding system
First Claim
1. A variable length coding system, which assigns, to a plurality of source symbols, code words having a code length corresponding to the occurrence probability of the source symbols and which outputs code words corresponding to inputted source symbols as coded data, said variable length coding system comprising:
- a code-word table for storing therein a plurality of code words including codes words, which are capable of being decoded both in forward and backward directions and which are formed so that delimiters of the code words are capable of being identified by a predetermined weight of the code words, so that said plurality of code words correspond to source symbols;
code-word selecting means for selecting code words corresponding to inputted source symbols from the code-word table; and
synchronization interval setting means for preparing coded data for each of predetermined synchronization intervals using code words selected by said code-word selecting means and for inserting stuffing codes capable of being decoded in the backward direction.
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Abstract
A coding and/or decoding system includes: a code-word table for storing therein a plurality of code words, which are capable of being decoded both in forward and backward directions and which are formed so that delimiters of the code words are capable of being identified by a predetermined weight of the code words, so that the code words correspond to different source symbols; an encoder for selecting code words corresponding to inputted source symbols from the code-word table; and a synchronization interval setting part for preparing coded data every predetermined interval using the code words selected by the encoder and for inserting stuffing codes capable of being decoded in the backward direction. Thus, it is possible to decrease useless bit patterns to enhance the coding efficiency by smaller amounts of calculation and storage, and to decode variable length codes both in the forward and backward directions even if the synchronization interval is set every interval using the stuffing bits.
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Citations
51 Claims
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1. A variable length coding system, which assigns, to a plurality of source symbols, code words having a code length corresponding to the occurrence probability of the source symbols and which outputs code words corresponding to inputted source symbols as coded data, said variable length coding system comprising:
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a code-word table for storing therein a plurality of code words including codes words, which are capable of being decoded both in forward and backward directions and which are formed so that delimiters of the code words are capable of being identified by a predetermined weight of the code words, so that said plurality of code words correspond to source symbols;
code-word selecting means for selecting code words corresponding to inputted source symbols from the code-word table; and
synchronization interval setting means for preparing coded data for each of predetermined synchronization intervals using code words selected by said code-word selecting means and for inserting stuffing codes capable of being decoded in the backward direction. - View Dependent Claims (2, 3, 4, 5)
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6. A variable length coding system, which assigns, to a plurality of source symbols, code words having a code length corresponding to the occurrence probability of the source symbols and which outputs code words corresponding to inputted source symbols as coded data, said variable length coding system comprising:
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layering means for layering inputted source symbols in accordance with importance;
a code-word table for storing therein a plurality of code words including codes words, which are capable of being decoded both in the forward and backward directions and which are formed so that the delimiters of the code words are capable of being identified by a predetermined weight of the code words, so that said plurality of code words correspond to the source symbols;
code-word selecting means for selecting code words corresponding to the inputted source symbols layered by said layering means, from the code-word table; and
synchronization interval setting means for preparing coded data of each of layers for each of predetermined synchronization intervals using code words selected by said code-word selecting means and for multiplexing the coded data of each of layers. - View Dependent Claims (7, 8, 9, 10)
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11. A variable length decoding system for decoding coded data, which are of variable length codes of code words containing code words capable of being decoded both in forward and backward directions and into which stuffing codes capable of being decoded in the backward direction are inserted every predetermined synchronization interval, said variable length decoding system comprising:
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synchronization interval detecting means for detecting a synchronization interval of said coded data;
forward decoding means for decoding, in the forward direction, the coded data in the synchronization interval detected by said synchronization interval detecting means; and
backward decoding means for decoding, in the backward direction, the data in the synchronization interval detected by said synchronization interval detecting means. - View Dependent Claims (12, 13, 14, 15)
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16. A variable length decoding system for decoding coded data, which are of variable length codes of code words containing code words capable of being decoded both in forward and backward directions and into which stuffing codes capable of being decoded in the backward direction are inserted every predetermined synchronization interval, said variable length decoding system comprising:
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synchronization interval detecting means for detecting a synchronization interval of said coded data;
forward decoding means for decoding, in the forward direction, the coded data in the synchronization interval detected by said synchronization interval detecting means;
backward decoding means for decoding, in the backward direction, the data in the synchronization interval detected by said synchronization interval detecting means; and
decoded-value determining means for determining a decoded value on the basis of decoded results of said forward decoding means and said backward decoding means to output a final decoded result. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 34)
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24. A variable length decoding system for decoding coded data every predetermined synchronization interval, said coded data comprising variable length codes, which are of code words containing code words capable of being decoded both in forward and backward directions, and said coded data being prepared by code words corresponding to layered source symbols to be multiplexed, said variable length decoding system comprising:
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dividing means for dividing said multiplexed coded data into respective layers;
synchronization interval detecting means for detecting a synchronization interval of said coded data divided by said dividing means;
forward decoding means for decoding, in the forward direction, the coded data in the synchronization interval detected by said synchronization interval detecting means;
backward decoding means for decoding, in the backward direction, the data in the synchronization interval detected by said synchronization interval detecting means; and
synthesizing means for synthesizing decoded results of respective layers obtained by said forward decoding means and said backward decoding means. - View Dependent Claims (25, 26, 27)
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28. A variable length decoding system for decoding coded data every predetermined synchronization interval, said coded data comprising variable length codes, which are of code words containing code words capable of being decoded both in forward and backward directions, and said coded data being prepared by code words corresponding to layered source symbols to be multiplexed, said variable length decoding system comprising:
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dividing means for dividing said multiplexed coded data into respective layers;
synchronization interval detecting means for detecting a synchronization interval of said coded data divided by said dividing means;
forward decoding means for decoding, in the forward direction, the coded data in the synchronization interval detected by said synchronization interval detecting means;
backward decoding means for decoding, in the backward direction, the data in the synchronization interval detected by said synchronization interval detecting means;
decoded-value determining means for determining decoded values on the basis of decoded results of respective layers obtained by said forward decoding means and said backward decoding means, to output final decoded results; and
synthesizing means for synthesizing final decoded results of respective layers obtained by said decoded-value determining means. - View Dependent Claims (29, 30, 31, 32, 33)
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35. A variable length decoding system for decoding coded data, which are of variable length codes of code words containing code words capable of being decoded both in forward and backward directions and into which stuffing codes capable of being decoded in a backward direction are inserted every predetermined synchronization interval, said variable length decoding system comprising:
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synchronization interval detecting means for detecting a synchronization interval of said coded data; and
bidirectional decoding means for decoding, both in forward and backward directions, the coded data in the synchronization interval detected by said synchronization interval detecting means. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A recording medium for having recorded therein data for use in a variable length coding and/or decoding system, said recording medium having recorded therein variable length coded data capable of being inputted and outputted by the variable length coding and/or decoding system, said recording medium recording therein:
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coded data including code words, which are capable of being decoded both in forward and backward direction and which are formed so that the delimiters of the code words are identified by a predetermined weight of the code words; and
data, in which stuffing codes capable of being decoded in the backward direction every predetermined synchronization interval are inserted into said coded data.
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49. A recording medium for having recorded therein data for use in a variable length coding and/or decoding system, said recording medium having recorded therein transform coefficient data capable of being produced by orthogonal transforming every block in an image coding and/or decoding system, said recording medium recording therein:
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said transform coefficient data, wherein a plurality of code words capable of being decoded both in forward and backward directions correspond to orthogonal transform coefficients having high appearance frequencies other than the last orthogonal transform coefficients of the block, for each of a plurality of coded modes of said image coding and/or decoding system;
data, wherein a plurality of code words capable of being decoded both in the forward and backward directions are commonly provided for a plurality of coded modes of said image coding and/or decoding system and correspond to orthogonal transform coefficients having high appearance frequencies of the last orthogonal transform coefficients of the block;
data, wherein transform coefficient data having a low appearance frequency are described by fixed length codes, and code words capable of being decoded both in forward and backward directions are added to the prefix and suffix thereof; and
data, wherein stuffing codes capable of being decoded in the backward direction are inserted in the coded data every predetermined synchronization interval.
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50. A recording medium having recorded therein a program for use in a variable length coding system, which assigns, to a plurality of source symbols, code words having a code length according to occurrence probability of the source symbols, to output code words corresponding to inputted source symbols as coded data, said recording medium including at least the steps of:
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storing a code-word table, wherein a plurality of code words including code words, which are capable of being decoded both in forward and backward directions and which are formed so that the delimiters of the code words are capable of being identified by a predetermined weight of the code words, correspond to source symbols;
selecting code words corresponding to said inputted source symbols from said code-word table; and
preparing coded data every synchronization interval by using the code words selected by said code-word selecting step, and setting a synchronization interval to said code words by inserting stuffing codes capable of being decoded in the backward direction.
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51. A recording medium having recorded therein a program for use in a variable length decoding system for decoding coded data, which are of variable length codes of code words including code words capable of being decoded both in forward and backward directions and into which stuffing codes capable of being decoded in the backward direction are inserted every predetermined synchronization interval, said recording medium including at least the steps of:
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detecting a synchronization interval of said coded data;
decoding the coded data in the synchronization interval detected by said synchronization interval detecting step in the forward direction; and
decoding the coded data in the synchronization interval detected by said synchronization interval detecting step in the backward direction.
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Specification