Abstract: One embodiment disclosed relates to a method for encoding and decoding a video sequence in which a keyframe is used to bi-directionally predict frames in the sequence. The keyframe is coded independently of other frames in the sequence. Both a prior frame occurring before the keyframe and a subsequent frame occurring after the keyframe are predicted using data from the keyframe. Another embodiment disclosed relates to a method for allocating bits to a keyframe during video encoding. Effects of a plurality of keyframe bit allocations on quality of a predicted frame are measured. Said effects are used to determine a near optimal keyframe bit allocation.

Abstract: One embodiment disclosed relates to a method for encoding and decoding a video sequence in which a keyframe is used to bi-directionally predict frames in the sequence. The keyframe is coded independently of other frames in the sequence. Both a prior frame occurring before the keyframe and a subsequent frame occurring after the keyframe are predicted using data from the keyframe. Another embodiment disclosed relates to a method for allocating bits to a keyframe during video encoding. Effects of a plurality of keyframe bit allocations on quality of a predicted frame are measured. Said effects are used to determine a near optimal keyframe bit allocation.

Abstract: In a method and apparatus for predicting and coding motion vectors in a video compression scheme, an ordered list of segments for a reference frame is used to create a hierarchy of segments with a plurality of levels. Motion vectors for segments in the top level are entropy coded, and these vectors are used to predict vectors for segments at the next level. Residual vectors are entropy coded to correct these predictions, and the process of prediction from above and coding residuals continues recursively down through the hierarchy of segment levels. Information about the previous motion of segments may be exploited in the prediction process. In a complementary method and apparatus for decoding motion vectors, the same segment hierarchy is used to predict motion vectors by the same method used during encoding, and these predicted vectors are added to residual motion vectors to reconstruct the actual motion vectors.

Abstract: A method and apparatus for predicting and coding motion vectors in a video compression scheme is disclosed. An ordered list of segments for a reference frame is used to create a hierarchy of segments with a plurality of levels. Motion vectors for segments in the top level are entropy coded, and these vectors are used to predict vectors for segments at the next level. Residual vectors are entropy coded to correct these predictions, and the process of prediction from above and coding residuals continues recursively down through the hierarchy of segment levels. Information about the previous motion of segments may be exploited in the prediction process. A complementary method and apparatus for decoding motion vectors is also disclosed. The same segment hierarchy is used to predict motion vectors by the same method used during encoding, and these predicted vectors are added to residual motion vectors to reconstruct the actual motion vectors.