Abstract: There is provided a method and apparatus for scene change detection for use with bit-rate control of a video compression system. The method and apparatus may be used for scene change detection in intra-coded and/or inter-coded pictures. The method comprises the steps of: compressing each picture in a video signal in turn; determining complexity data from the compressed signal for each picture after partial compression of the picture; determining from the complexity data whether a scene change may have taken place; and adjusting the compression step and allocated compressed bit number for pictures after a scene change detection in dependence on the result of the determination. For an intra-coded picture, the complexity data is a monotonically increasing function of a quantisation parameter and a compressed bit number used in the compression step for the partial compression from which the complexity data is determined.

Abstract: A method and apparatus are provided for video edge filtering in which a buffer stores pixels required for edge filtering from a plurality of macroblocks. An input tile buffering unit comprising a plurality of dual port tile buffers receives tile portions of each macroblock. These are transposed selectively and provided to a programmable edge filter which performs one dimensional edge filtering on the tile portions. The filtered edges are then selectively transposed in a opposite manner to the first transpose unit and provided to an output buffer as well as provided back to the dual port tile buffers for use in further filtering.

Abstract: A method and apparatus are provided for performing overlap transform and deblocking of a decompressed video signal. The video image is sub-divided into a plurality of non-overlapping macroblocks, each of which comprises a plurality of smaller sub-blocks. Each macroblocks comprises two luminance partitions and one chrominance partition. Each partition is buffered and further buffering is provided for sub-blocks of each partition. Overlap transform and deblocking are performed by buffering sub-blocks from current partitions and sub-blocks from partitions from adjacent macroblocks. Overlap transform is performed in the current macroblock for buffered sub-blocks and deblocking is performed for blocks in the adjacent macroblocks.

Abstract: A method and apparatus are provided for video motion compensation suitable for use in decoding compressed video. An input buffer receives lines of blocks of video data and outputs lines of these to a first block transpose unit 52. This can selectively transpose the lines and columns of an input block of pixels. A vertical line filtering unit 58 is coupled to the block transpose unit for producing an output line of interpolated pixel samples. A first selector with inputs coupled to the output of the vertical line filtering unit and to the output of the input block transpose unit is able to select between an un-interpolated output line of pixels and an interpolated output line of pixel samples. A second selector 62 with inputs coupled to the outputs of the first block transpose unit and to the vertical line filtering unit is able to select between lines of pixels from the first input block transpose unit and from the vertical line filtering unit and provides these to a horizontal line filtering unit 66.