An encoding method of encoding units included in a picture is provided. The encoding method generates a first flag indicating whether a removal time of encoded data from a buffer by a hypothetical decoder is set per unit. When the removal time is set per unit, a second flag is generated which indicates whether an interval between removal times of the units is constant. When the second flag indicates that the interval is constant, common-interval information is generated which is distinct from the second flag and indicates a constant time interval between the removal times of the units. A bitstream including the encoded data, the first flag, the second flag, and the common-interval information is generated. The first flag is included in video usability information of the bitstream. The second flag and the common-interval information are included in control information of the bitstream.