Compact image transmission system and image reproducing device capable of reproducing a DCT-based code at a high speed without deterioration of picture quality

An image transmission system comprising:

• preparing means for preparing an intraframe encoded image by segmenting an image into a plurality of blocks and by compressing and encoding each block by the use of discrete cosine transform;
• preparing means for preparing an interframe encoded image by searching for a particular block at which a difference is smallest between a current frame and either a preceding frame or both preceding and succeeding frames in a time sequential order, by carrying out motion compensation on said each block, and by compressing and encoding a differential value between each block of said current frame and a motion compensated block by the use of discrete cosine transform;
• multiplexing and transmitting means for multiplexing and transmitting said intraframe encoded image and said interframe encoded image in a plurality of frames together with a sequence header which is included in a first frame of said plurality of frames at a beginning of said first frame;
• transmitting means for transmitting an identifier for identifying at least one of fixed parameters including a type of said interframe encoded image to be transmitted with said intraframe encoded image and a motion compensation value, said identifier being transmitted to a reproducing side within said sequence header;
• and
• expansion processing means for carrying out expansion processing after detecting said identifier in said header to thereby identify said fixed parameter of an input video code.