Image encoding device and method, and image processing device and method for enabling bitstream concatenation

An image encoding method comprising:

• setting header information related to a hypothetical reference decoder in accordance with information about position of a current picture of image data to be processed and information about whether the current picture is a reference picture to be referred to;
• and
• encoding the image data and generating a bitstream containing the encoded data of the image data and the set header information, the encoding enabling concatenation of the bitstream with another bitstream,
• wherein the setting of the header information comprises setting information indicating a NAL unit type, based on whether or not the current picture is a first picture of a concatenating bitstream, a last picture of a bitstream to be concatenated, and the reference picture to be referred to.

A non-transitory computer-readable medium having embodied thereon a program, which when executed by a computer, causes the computer to execute a method, the method comprising:

• setting header information related to a hypothetical reference decoder in accordance with information about position of a current picture of image data to be processed and information about whether the current picture is a reference picture to be referred to;
• and
• encoding the image data and generating a bitstream containing the encoded data of the image data and the set header information, the encoding enabling concatenation of the bitstream with another bitstream,
• wherein the setting of the header information comprises setting information indicating a NAL unit type, based on whether or not the current picture is a first picture of a concatenating bitstream, a last picture of a bitstream to be concatenated, and the reference picture to be referred to.