Multi-level bidirectional motion estimation method and device

A multi-level bidirectional motion estimation device, comprising:

• a match searching unit, configured to search for matched blocks in a current frame and a previous frame respectively by using M1×M1 blocks of a to-be-interpolated frame as a mirror center, wherein the previous frame is a frame before the to-be-interpolated frame, the current frame is a frame after the to-be-interpolated frame, and a algorithm for the search comprises a three-dimensional recursive search algorithm or a hexagon search algorithm;
• and
• a determining unit, configured to determine a first to-be-determined matched block pair corresponding to the M1×M1 blocks of the to-be-interpolated frame, wherein the first to-be-determined matched block pair is a pair of matched blocks with a minimum sum of binary absolute difference (SBAD) value among all pairs of matched blocks searched out by the searching unit in the current frame and the previous frame, wherein
• the determining unit is further configured to determine motion vectors of the M1×M1 blocks of the to-be-interpolated frame according to motion vectors of the first to-be-determined matched block pair if it is determined that an SHAD value of the first to-be-determined matched block pair is less than an SBAD threshold;
• and
• the match searching unit is further configured to:
• if the SBAD value of the first to-be-determined matched block pair, which is determined by the determining unit, is greater than or equal to the SBAD threshold, split the M1×M1 blocks of the to-be-interpolated frame into M2×M2 blocks, and search for matched blocks again in the current frame and the previous frame respectively by using the M2×M2 blocks of the to-be-interpolated frame as a mirror center, wherein an SBAD threshold for searching for the matched blocks again is ¼ of the SHAD threshold applied in the previous time of searching for the matched blocks, both M1 and M2 are 2 to the power of m, m is a positive integer, and M2=M1/2.