A decoder for decoding video, wherein (a) the decoder is configured to receive a bitstream; (b) the decoder is configured to decode the bitstream using one of a regular decoding engine and a bypass decoding engine in a context adaptive binary arithmetic coding; and (c) the decoder is configured to select an intra prediction mode of a plurality of intra prediction modes, wherein (d) the decoder is configured to decode first information using the regular decoding engine, the first information indicates whether an intra prediction mode for a current block is selected from most probable modes generated using an intra prediction mode of a block to the left of the current block and an intra prediction mode of a block above the current block; (e) in a case that the decoder identifies that the first information indicates that the intra prediction mode of the current block is selected from the most probable modes, the decoder is configured to decode second information used for selecting an intra prediction mode from the most probable modes using the bypass decoding engine; and (f) in a case that the decoder identifies that the first information indicates that the intra prediction mode of the current block is not selected from the most probable modes, the decoder is configured to decode third information using the bypass decoding engine, the third information is used for selecting an intra prediction mode from intra prediction modes that are not the most probable modes and that were also generated using the intra prediction mode of the block to the left of the current block and the intra prediction mode of the block above the current block. (a) the decoder is configured to receive a bitstream; (b) the decoder is configured to decode the bitstream using one of a regular decoding engine and a bypass decoding engine in a context adaptive binary arithmetic coding; and (c) the decoder is configured to select an intra prediction mode of a plurality of intra prediction modes, wherein (d) the decoder is configured to decode first information using the regular decoding engine, the first information indicates whether an intra prediction mode for a current block is selected from most probable modes generated using an intra prediction mode of a block to the left of the current block and an intra prediction mode of a block above the current block; (e) in a case that the decoder identifies that the first information indicates that the intra prediction mode of the current block is selected from the most probable modes, the decoder is configured to decode second information used for selecting an intra prediction mode from the most probable modes using the bypass decoding engine; and (f) in a case that the decoder identifies that the first information indicates that the intra prediction mode of the current block is not selected from the most probable modes, the decoder is configured to decode third information using the bypass decoding engine, the third information is used for selecting an intra prediction mode from intra prediction modes that are not the most probable modes and that were also generated using the intra prediction mode of the block to the left of the current block and the intra prediction mode of the block above the current block.