Patent ID: 7724819

Claim:
An image encoding device, which outputs as an encoded bitstream combined image information, including a first information portion modulated by a first modulation method and a second information portion modulated by a second modulation method different from said first modulation method with different transmission rates that can be used with time division, said first and second modulation method being used to transmit serially, and wherein said first information portion and said second information portion is divided from an image data, comprising an encoder, which encodes said combined image data, and comprises quantization means which performs quantization of input data based on a quantization value; and, encoding amount control means, which controls the amount of encoding of the encoder, having: first information counting means, which counts the number of bits of said first information portion; second information counting means, which counts the number of bits of said second information portion; first information portion transmission time computation means, which computes the time required for transmission of said encoded first information portion using said first modulation method, based on the number of bits of said first information portion counted by said first information portion counting means; second information portion transmission time computation means, which computes the time available for transmission of said encoded second information portion, based on the time required for transmission of said first encoded information portion and the total transmission time, which is the total time available for transmission; second information portion transmittable bits computation means, which computes the number of bits of said second information portion which can be transmitted, based on the time available for transmission of said encoded second information portion and said second modulation means; untransmitted bits computation means, which computes the number of untransmitted bits exceeding the number of transmittable bits of said second information portion, based on the number of transmittable bits of said second information portion and the number of bits of said second information portion counted by said second information portion counting means; and, quantization value computation means, which computes and outputs to said quantization means a quantization value for said second information portion for use in the next image encoding consisting of said number of untransmitted bits of said second information portion, keeping the sum of the time required for transmission of the first information portion and the time required for transmission of the second information portion essentially constant over more than one transmission interval based on said number of untransmitted bits; and wherein a ratio of an amount of information in the first information portion to an amount of in formation in the second information portion changes from a first transmission interval to a second transmission interval.