A system for coding an I-picture that satisfies a predetermined condition using parameter information. When it is determined that a picture type is the I-picture, it is determined whether or not the phase of a macro block in previous coding agrees with that of the macro block of present coding. When the phases of the macro blocks agree with each other, it is determined whether or not amount of generated code in a unit of picture in decoding≦target amount of code×α is satisfied. When the condition is satisfied, it is determined whether or not an image frame of previous coding is the same as that of previous coding. When the image frames are not the same, the information of a picture type, motion vector, and a quantized value included in the parameter information is reused, whereas when the image frames are the same, the stream data input to a decoder is output. When the above condition is not satisfied, the parameters are not reused. The present invention can be applied to a coder, a coding apparatus, an information recording apparatus, an information reproducing apparatus, or a transcoder.