A microcomputer retains a group definition table associating the sector sections created by dividing all sectors into multiple sections under a given condition with different memory regions on a flash memory, respectively. The CSI may be at least one of a frame error rate, a bit error rate, a signal to noise ratio, and a signal to interference plus noise ratio. Input streams from each endpoint are uncompressed, resized, and scaled to fit the segment in the layout for particular endpoints, and then encoded by a sub-encoder into a sub-encoded stream according to the compression parameters.