Apparatus for prediction coding or decoding image signal and method therefor
First Claim
1. An apparatus for predicting a Discrete Cosine Transform (DCT) component of an image signal in an apparatus for prediction coding or decoding an image signal, the apparatus for predicting a DCT component comprising:
- a packet change detection unit which determines whether or not blocks used to determine a prediction direction for a current block for which prediction is currently performed is included in a same packet to which the current block belongs;
a prediction reference value providing unit which provides a prediction reference value used in prediction according to the result of determination by the packet change detection unit; and
a prediction calculation unit which outputs a predictive coded value or a predictive decoded value using the prediction reference value provided by the prediction reference value providing unit and the DCT component of the current block according to an operation mode.
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Abstract
A hardware structure for adaptively prediction coding an image signal using spatial correlation and a method therefor are provided. The prediction coding apparatus has a packet change detection unit which determines whether or not blocks used to determine a prediction direction for a current block for which prediction is currently performed is included in a same packet to which the current block belongs; a prediction reference value providing unit which provides a prediction reference value used in prediction according to the result of determination by the packet change detection unit; and a prediction calculation unit which outputs a predictive coded value or a predictive decoded value using the prediction reference value provided by the prediction reference value providing unit and the DCT component of the current block according to an operation mode. According to the apparatus and method, the size of a prediction apparatus is reduced, and one apparatus is used both in coding and decoding.
23 Citations
15 Claims
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1. An apparatus for predicting a Discrete Cosine Transform (DCT) component of an image signal in an apparatus for prediction coding or decoding an image signal, the apparatus for predicting a DCT component comprising:
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a packet change detection unit which determines whether or not blocks used to determine a prediction direction for a current block for which prediction is currently performed is included in a same packet to which the current block belongs; a prediction reference value providing unit which provides a prediction reference value used in prediction according to the result of determination by the packet change detection unit; and a prediction calculation unit which outputs a predictive coded value or a predictive decoded value using the prediction reference value provided by the prediction reference value providing unit and the DCT component of the current block according to an operation mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for predicting an image signal in a method for predictive coding or predictive decoding an image signal using a prediction memory which comprises a horizontal direction memory unit which has storage areas capable of storing horizontal DCT components of a slice forming a scene, a vertical direction memory unit which has storage areas capable of storing a vertical DCT component, and an upper-left memory unit storage areas capable of storing a DC component of a block immediately above and to the left of a current block for which prediction is performed, the method for prediction an image signal comprises:
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(a) determining whether or not the packet to which the current macro block belongs is different from the packet of a macro block to the left of the current macro block, the macro block immediately above and to the left of the current block, or a macro block immediately above the current macro block, using a current packet change signal indicating whether or not the packet to which the current macro block belongs changed; (b) if the packet to which the current macro block belongs is the same as the packet of the macro block to the left of the current macro block, the macro block immediately above and to the left of the current block, or the macro block immediately above the current macro block, determining the direction of prediction, using the DC component of the block to the left of the current block stored in the vertical direction memory unit, the DC component of the block immediately above the current block stored in the horizontal direction memory unit, and the DC component of the block immediately above and to the left of the current block; (c) if the prediction direction is a first direction, outputting a reference prediction value by using a value stored in the vertical direction memory unit and if the prediction direction is a second direction, outputting a reference prediction value by using a value stored in the horizontal direction memory unit; (d) if the packet to which the current macro block belongs is different from the packet of the macro block to the left of the current macro block, the macro block immediately above and to the left of the current block, or the macro block immediately above the current macro block, outputting a predetermined reference value; (e) performing prediction calculation by using the reference prediction value of step (c) or the predetermined reference value of step (c) with the DCT component of the current block; and (f) storing the DCT component of the current block in the prediction memory. - View Dependent Claims (13, 14)
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15. A computer readable medium having embodied thereon a computer program for implementing a method for predicting an image signal in a method for predictive coding or predictive decoding an image signal using a prediction memory which comprises a horizontal direction memory unit which has storage areas capable of storing horizontal DCT components of a slice forming a scene, a vertical direction memory unit which has storage areas capable of storing vertical DCT components, and an upper-left memory unit storage areas capable of storing a DC component of a upper left-hand block of a current block for which prediction is performed, the method for prediction an image signal comprises:
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(a) determining whether or not the packet to which the current macro block belongs is different from the packet of a left-hand macro block of the current macro block, the upper left-hand macro block of the current macro block, or an upper macro block of the current macro block, using a current packet change signal indicating whether or not the packet to which the current macro block belongs changed; (b) if the packet to which the current macro block belongs is the same as the packet of the left-hand macro block of the current macro block, the upper left-hand macro block of the current macro block, or the upper macro block of the current macro block, determining the direction of prediction, using the DC component of the left-hand block of the current block stored in the vertical direction memory unit, the DC component of the upper block of the current block stored in the horizontal direction memory unit, and the DC component of the upper left-hand block of the current block; (c) if the prediction direction is a first direction, outputting a reference prediction value by using a value stored in the vertical direction memory unit and if the prediction direction is a second direction, outputting a reference prediction value by using a value stored in the horizontal direction memory unit; (d) if the packet to which the current macro block belongs is different from the packet of the left-hand macro block of the current macro block, the upper left-hand macro block of the current macro block, or the upper macro block of the current macro block, outputting a predetermined reference value; (e) performing prediction calculation by using the reference prediction value of step (c) or the predetermined reference value of step (c) with the DCT component of the current block; and (f) storing the DCT component of the current block in the prediction memory.
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Specification