1. A method for decoding of a video bitstream by a video decoding circuit, the method comprising:receiving coded data for a 2N×2N coding unit (CU) from the video bitstream;
selecting one or more first codewords according to whether asymmetric motion partition is disabled or enabled when a size of said 2N×2N CU is not equal to a smallest CU size, wherein none of said one or more first codewords corresponds to INTER N×N partition;
selecting one or more second codewords when the size of said 2N×2N CU is equal to the smallest CU size, wherein none of said one or more second codewords corresponds to the INTER N×N partition when N is 4;
determining a CU structure for said 2N×2N CU from the video bitstream using said one or more first codewords or said one or more second codewords; and
decoding the video bitstream using the CU structure.