| 摘要 |
<p>A video decoder is disclosed that is operable to decode predictively encoded data wherein each encoded data segment has been encoded with a local weighting parameter. When encoding each segment of a picture, a weighting parameter is derived from a previously encoded segment of the picture. Advantageously, by allowing for different weighting parameters for each segment, the illumination changes within the picture are adapted to better than if a single global weighting parameter is used for all of the segments of a picture. Applications include MPEG video encoding and decoding. Accordingly, there is provided a video decoder operable to decode predictively-encoded video data defining a sequence of pictures, each picture divided into a plurality of segments, the decoder comprising a decoder operable to decode the encoded video data to generate decoded difference data (MBr') for a segment of a picture, motion data (14) for the segment and at least one weighting parameter for the segment; a motion-compensated-data generator operable to process the motion data and previously decoded video data to generate motion-compensated video data (MBc') for the segment; a predicted-data generator operable to generate predicted video data (MBp) for the segment by combining the motion-compensated video data (MBc') for the segment with at least one weighting parameter for the segment that is different from a weighting parameter used for a different segment in the same picture; and a data combiner operable to combine the decoded difference data (MBr') for the segment with the predicted video data (MBp) for the segment.</p> |
