Video coding system
First Claim
1. An encoder for performing motion compensated encoding of a sequence of video frames having picture elements, the encoder comprising:
- a memory for storing a reference frame;
a motion field estimation block arranged to refine a set of prediction motion coefficients, previously estimated for an at least one first picture element of a current frame, by using a series of motion estimation methods of varying complexity to generate a first candidate set of motion coefficients for a second picture element of the current frame, and arranged to select either a set of initial motion coefficients or motion coefficients estimated using the reference frame as a selected set of motion coefficients, and to refine the set of selected motion coefficients by using a series of motion estimation methods of varying complexity to generate a second candidate set of motion coefficients for the at least one second picture element of the current frame; and
a motion field coding block for comparing the first candidate set of motion coefficients and the second candidate set of motion coefficients in order to choose one set of motion coefficients to be used to represent motion of the second picture element.
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Abstract
A motion estimation method and system for a video coder are disclosed. The system comprises an input for a video image to be coded. It also comprises a hierarchical series of motion estimators of varying complexity, for estimating a motion vector field between the received image and a reference image. The subsequent motion estimator in the series is selected by a control means if a prediction error associated with the motion vector field estimated by the currently selected motion estimator exceeds a predetermined threshold. When available, inherited and predicted motion information is used to improve prediction quality.
29 Citations
34 Claims
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1. An encoder for performing motion compensated encoding of a sequence of video frames having picture elements, the encoder comprising:
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a memory for storing a reference frame;
a motion field estimation block arranged to refine a set of prediction motion coefficients, previously estimated for an at least one first picture element of a current frame, by using a series of motion estimation methods of varying complexity to generate a first candidate set of motion coefficients for a second picture element of the current frame, and arranged to select either a set of initial motion coefficients or motion coefficients estimated using the reference frame as a selected set of motion coefficients, and to refine the set of selected motion coefficients by using a series of motion estimation methods of varying complexity to generate a second candidate set of motion coefficients for the at least one second picture element of the current frame; and
a motion field coding block for comparing the first candidate set of motion coefficients and the second candidate set of motion coefficients in order to choose one set of motion coefficients to be used to represent motion of the second picture element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for performing motion compensated encoding of a sequence of video frames having picture elements, the method comprising the steps of:
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storing a reference frame;
when a set of prediction motion coefficients previously estimated for an at least one first picture element of a current frame is available, refining the set of prediction motion coefficients by using a series of motion estimation methods of varying complexity to generate a first candidate set of motion coefficients for a second picture element of the current frame;
selecting either a set of initial motion coefficients or motion coefflcients estimated using the reference frame as a selected set of motion coefficients, refining the set of selected motion coefficients by using a series of motion estimation methods of varying complexity to generate a second candidate set of motion coefficients for the second picture element of the current frame; and
comparing the first candidate set of motion coefficients and the second candidate set of motion coefficients in order to choose one set of motion coefficients to be used to represent motion of the second picture element. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification