Image coding method, decoding apparatus, and computer program implementing a display cycle identifier

An image coding method for coding an image signal, said method comprising:

• outputting a coded image signal obtained by coding the image signal together with a reproduction cycle identifier operable to indicate that a cycle of image reproduction for all frames included in the image signal is fixed;
• and
• outputting sub-unit time data operable to indicate a natural number N for use in showing a length of a sub-unit time which is obtainable by dividing a prescribed time interval by the natural number N, and reproduction cycle multiplier data operable to indicate natural number M for use in showing that a cycle of image reproduction for the frames is M times of the sub-unit time (sub-unit time×M), together with the reproduction cycle identifier when the reproduction cycle identifier indicates that the cycle of image reproduction is fixed.

A computer program embodied on a computer readable data storage medium for use with a computer for encoding an image signal, said computer program comprising:

• computer readable program code operable to cause the computer to output a coded image signal obtained by coding the image signal together with a reproduction cycle identifier operable to indicate that a cycle of image reproduction for all frames included in the image signal is fixed;
• and
• computer readable program code operable to cause the computer to output sub-unit time data operable to indicate a natural number N for use in showing a length of a sub-unit time which is obtainable by dividing a prescribed time interval by the natural number N, and reproduction cycle multiplier data operable to indicate natural number M for use in showing that a cycle of image reproduction for the frames is M times of the sub-unit time (sub-unit time×M), together with the reproduction cycle identifier when the reproduction cycle identifier indicates that the cycle of image reproduction is fixed.