Communication terminal
First Claim
1. A communication terminal comprising:
- a coding part for coding a moving picture by selectively using one of an intra-coding mode and an inter-coding mode;
wherein, if the intra-coding mode is used by the coding part, the coding part;
calculates a difference signal by subtracting, from a first block to be coded which is in a first size and is divided from the moving picture, a prediction block in the first size generated using at least one block adjacent to the first block to be coded;
divides the difference signal into a plurality of second blocks in a second size;
calculates a prediction error from the difference signal based on the second blocks;
compares the prediction error with a predetermined threshold; and
calculates one of;
(i) both a quantized AC component and a quantized DC component by executing a discrete cosine transform and quantization on the difference signal if the prediction error is greater than the threshold, and (ii) only a quantized DC component by executing the discrete cosine transform and quantization on the difference signal if the prediction error is less than or equal to the threshold.
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Accused Products
Abstract
A communication terminal performs a discrete cosine transform and a quantization process in accordance with a selected coding mode so as to reduce loads caused by these processings and suppress degradation of picture quality. When performing coding of a moving picture inputted through a picture input part, a control part determines which coding mode among 4×4 intra prediction coding on a luminance signal, 16×16 intra prediction coding, intra prediction coding on a color-differential signal, and inter prediction coding is performed. In accordance with the selected coding mode, and in view of a predictive error, the processing content in the discrete cosine transform and the quantization process is switched.
26 Citations
20 Claims
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1. A communication terminal comprising:
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a coding part for coding a moving picture by selectively using one of an intra-coding mode and an inter-coding mode; wherein, if the intra-coding mode is used by the coding part, the coding part; calculates a difference signal by subtracting, from a first block to be coded which is in a first size and is divided from the moving picture, a prediction block in the first size generated using at least one block adjacent to the first block to be coded; divides the difference signal into a plurality of second blocks in a second size; calculates a prediction error from the difference signal based on the second blocks; compares the prediction error with a predetermined threshold; and calculates one of;
(i) both a quantized AC component and a quantized DC component by executing a discrete cosine transform and quantization on the difference signal if the prediction error is greater than the threshold, and (ii) only a quantized DC component by executing the discrete cosine transform and quantization on the difference signal if the prediction error is less than or equal to the threshold. - View Dependent Claims (2, 3, 4, 5)
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6. A communication terminal comprising:
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a coding part for coding a moving picture by selectively using one of an intra-coding mode and an inter-coding mode; wherein, if the intra-coding mode is used by the coding part, the coding part; calculates a difference signal by subtracting, from a first block to be coded which is in a first size and is divided from the moving picture, a prediction block in the first size generated using at least one block adjacent to the first block to be coded; divides the difference signal into a plurality of second blocks in a second size; calculates a prediction error from the difference signal based on the second blocks; compares the prediction error with a predetermined threshold; and calculates one of;
(i) both a quantized AC component and a quantized DC component by executing a discrete cosine transform and quantization on the difference signal if the prediction error is greater than or equal to the threshold, and (ii) only a quantized DC component by executing the discrete cosine transform and quantization if the prediction error is less than the threshold. - View Dependent Claims (7, 8, 9, 10)
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11. A method of controlling a coding part of a communication terminal to code a moving picture by selectively using an intra-coding mode, comprising:
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calculating a difference signal by subtracting, from a first block to be coded which is in a first size and is divided from the moving picture, a prediction block in the first size generated using at least one block adjacent to the first block to be coded; dividing the difference signal into a plurality of second blocks in a second size; calculating a prediction error from the difference signal based on the second blocks; comparing the prediction error with a predetermined threshold; and calculating one of;
(i) both a quantized AC component and a quantized DC component by executing a discrete cosine transform and quantization on the difference signal if the prediction error is greater than the threshold, and (ii) only a quantized DC component by executing the discrete cosine transform and quantization on the difference signal if the prediction error is less than or equal to the threshold;wherein the coding part is also operable in an inter-coding mode. - View Dependent Claims (12, 13, 14, 15)
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16. A method of controlling a coding part of a communication terminal to code a moving picture by selectively using an intra-coding mode, comprising:
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calculating a difference signal by subtracting, from a first block to be coded which is in a first size and is divided from the moving picture, a prediction block in the first size generated using at least one block adjacent to the first block to be coded; dividing the difference signal into a plurality of second blocks in a second size; calculating a prediction error from the difference signal based on the second blocks; comparing the prediction error with a predetermined threshold; and calculating one of;
(i) both a quantized AC component and a quantized DC component by executing a discrete cosine transform and quantization on the difference signal if the prediction error is greater than or equal to the threshold, and (ii) only a quantized DC component by executing the discrete cosine transform and quantization if the prediction error is less than the threshold;wherein the coding part is also operable in an inter-coding mode. - View Dependent Claims (17, 18, 19, 20)
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Specification