In an earliest vertical synchronization period after sending an encoded image data is restarted, a first reference image determination circuit determines to employ a local decoded image generated in a vertical synchronization period immediately preceding a vertical synchronization period in which an error occurs among multiple local decoded images stored in a first DRAM as a reference image. In an earliest vertical synchronization period after a decoding circuit is reset, a second reference image determination circuit determines to employ a decoded image generated in the vertical synchronization period immediately preceding the vertical synchronization period in which the error occurs among multiple decoded images stored in a second DRAM as a reference image.