Video encoding and decoding using reference pictures

摘要

In the encoding of video data, a list of references pictures is constructed to be used in decoding. Prediction (direction) modes are defined by n-tuples (x0, x1, . . . , xM-1), where xm specifies prediction option of the m-th component of the motion vector field, m=0, . . . , M-1, where M components to the motion fields exist; where a coding option xm is an element from a set composed of all defined combinations of motion prediction modes and reference picture indices, with the addition of an option “/”, xmε{“/”, 0, 1, . . . , rm−1}; where option “/” specifies that the component is not used, and other options 0, 1, . . . , rm−1 specify one of rm combinations. A subset of all possible n-tuples is provided and a prediction mode used for predicting an inter-coded block is defined by reference to that subset.

主权项

1. A method of encoding video data defining a sequence of pictures using motion compensated motion prediction, the method comprising the steps in a video encoder of:
constructing a list of reference pictures to be used in decoding; defining prediction (direction) modes by constructing n-tuples (x0, x1, . . . , xM−1), where xm, specifies prediction option of the m-th component of a motion vector field, m=0, . . . , M−1, with M components to the motion field; where a coding option xm is an element from a set composed of all defined combinations of motion prediction modes and reference picture indices, with the addition of an option “/”, xmε{“/”, 0, 1, . . . , rm−1}; where option “/” specifies that the component is not used, and other options 0, 1, . . . , rm−1 specify one of rm combinations; providing a subset of T n-tuples of a set of all possible n-tuples; and defining a prediction mode used for predicting an inter-coded block by reference to a said n-tuple; wherein only one motion vector prediction mode is permitted for motion vector field component m, the prediction options are determined by the selection of reference pictures, and rm is the number of reference pictures that are available for motion vector field component m; wherein the subset of T n-tuples is provided by encoding the size of the subset of n-tuples, T, followed by either automatic derivation or explicit signalling of each n-tuple; wherein (x0, x1, . . . , xM−1), are encoded for each n-tuple, the n-tuple t, where t=0, . . . , T−1, being mapped to the prediction (direction) mode symbol St.