To realize real-time encoding in a two-path encoding system using only one encoding device.

The same uncompressed image data are outputted divisionally twice from an image memory which temporarily stores the inputted uncompressed image data and those are compressed and encoded by a single compressing and encoding means. In compressing and encoding with the compressing and encoding means which uses the 1st output, an optimum encoding parameter is computed according to the output of the compressing and encoding means and encoded data generated by the compressing and encoding means are discarded. In compressing and encoding by the compressing and encoding means using the 2nd output, compressing and encoding using an optimum encoding parameter found by the 1st compressing and encoding means is carried out and encoded data obtained by the compressing and encoding processing are outputted.