High efficiency coding apparatus
First Claim
1. A high efficiency coding apparatus for coding digital video data in a format composed of blocks of digital video data representing a three-dimensional group of picture elements belonging to a plurality of fields and for allowing video data compression for transmission by data transmission means having a predetermined transmission capacity, said apparatus comprising:
- first and second detecting means for detecing maximum and minimum values, respectively, of the digital video data representing the plural picture elements in each of said blocks;
means for generating dynamic range information for each said block from said maximum and minimum values for the respective block;
movement detecting means for detecting the amount of movement in each block and for generating a detected amount of movement;
means for generating distribution tables of said dynamic range information for each movement amount during a predetermined period by setting a first number to a table for a movement amount less than said detected amount of movement and by setting a second number to a table for a movement amount larger than said detected amount of movement;
means for determining a coding bit number for each block and a threshold value of said movement amount during said predetermined period from said distribution tables and said predetermined transmission capacity of said transmission means;
means for averaging digital data of plural video fields in a block in which said detected amount of movement is less than said threshold value;
encoding means for encoding the digital video data with said encoding bit number; and
means for transmitting an output of said encoding means, a first additional code for each block formed of at least two of said maximum value, minimum value and a signal based on said dynamic range information and a signal based on the detected amount of movement, and a second additional code for each said predetermined period.
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Abstract
A high efficiency coding apparatus controls the amount of generated information so that it does not surpass the transmission capacity of a transmission path when variable-length coding is employed for varying a word length corresponding to a dynamic range. With respect to a still block, distribution in which a movement amount is introduced is formed taking into account that frame-dropping processing is made to obtain the number of dynamic range occurrence. Not only threshold values in the level direction for defining a word length but also movement threshold values for the frame-dropping processing are changed to control the amount of generated information. As a result, the amount of generated information is controlled excellently without an increase in quantization errors.
169 Citations
6 Claims
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1. A high efficiency coding apparatus for coding digital video data in a format composed of blocks of digital video data representing a three-dimensional group of picture elements belonging to a plurality of fields and for allowing video data compression for transmission by data transmission means having a predetermined transmission capacity, said apparatus comprising:
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first and second detecting means for detecing maximum and minimum values, respectively, of the digital video data representing the plural picture elements in each of said blocks; means for generating dynamic range information for each said block from said maximum and minimum values for the respective block; movement detecting means for detecting the amount of movement in each block and for generating a detected amount of movement; means for generating distribution tables of said dynamic range information for each movement amount during a predetermined period by setting a first number to a table for a movement amount less than said detected amount of movement and by setting a second number to a table for a movement amount larger than said detected amount of movement; means for determining a coding bit number for each block and a threshold value of said movement amount during said predetermined period from said distribution tables and said predetermined transmission capacity of said transmission means; means for averaging digital data of plural video fields in a block in which said detected amount of movement is less than said threshold value; encoding means for encoding the digital video data with said encoding bit number; and means for transmitting an output of said encoding means, a first additional code for each block formed of at least two of said maximum value, minimum value and a signal based on said dynamic range information and a signal based on the detected amount of movement, and a second additional code for each said predetermined period. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification