A video bitstream is decoded by decoding a first syntax element with an integer value indicating a number of a plurality of entropy slices defining a first slice, a second syntax element indicating an offset, and a third syntax element indicating a slice type of the first slice. When the third syntax element indicates the slice type of the first slice is a B slice or a P slice, a flag in the slice header indicating an initialization method of a CABAC context is decoded, and the CABAC context is initialized using one of the first initialization method and the second initialization method. When the third syntax element indicates the slice type of the first slice is an I slice, the CABAC context is initialized using a third initialization method.