Patent ID: 6256345
Filing Date: 2001-07-03
Classification: H04N

Abstract:
A method for encoding a target block of an interlaced shape signal, wherein the interlaced shape signal includes a plurality of pictures, each picture being divided into a multiplicity of blocks of M.times.N pixels having one of a first and a second binary values, M and N being positive even integers, respectively, and the target block is encoded by either a frame-based coding to be encoded on an M.times.N pixel basis or a field-based coding to be encoded on an M/2.times.N pixels basis, the target block representing one of the blocks of a current picture to be encoded, comprising the steps of:(a) determining whether or not the target block is encoded with only noupdate binary alpha block type (BABtype), wherein the noupdate BABtype represents that the target block is encoded only by the BABtype itself, requiring no supplemental encoded data for the target block;(b) if the target block is not encoded with the noupdate BABtype, selecting either the frame-based or the field-based encodingtype as an encodingtype based on a degree of correlation between the target block and its two field blocks, wherein said two field blocks contain every odd row and every even row of the target block, respectively, each field block having M/2.times.N pixels, and the encodingtype indicates which of a frame-based coding discipline and a field-based coding discipline is used to encode the target block;(c) if the field-based coding is selected in step (b), deciding whether or not the two field blocks correspond to onefieldnoupdate, wherein said onefieldnoupdate represents that at least one of the two field blocks is replaced with a most similar candidate field block;(d) if the two field blocks are decided as a BABtype `1` of said onefieldnoupdate, finding toporbottom and BABtypefield, wherein said toporbottom indicates which of the two field blocks is replaced with the most similar candidate field block and the BABtypefield represents a coding condition of the other field block that is not indicated by the toporbottom; and(e) multiplexing the nondata BABtype, the encodingtype, the BABtype, the toporbottom and/or the BABtypefield.