Image compression of selected regions based on transmission bit rate, motion, and/or region information, and bit selection before compression based on transmission bit rate

摘要

An image encoding device is provided that can transmit encoded image data without lowering the frame rate even when the transmission speed of the transmission path is lowered. An encoded region designator selects the region that is to be encoded, in the input image, depending on the bit rate of the transmission path. Only such a region that is designated by the encoded region designator is encoded. The encoded region designator may be one which selects the region that is to be encoded, according to the bit rate of the transmission path, and the motion vector detected by the image encoding circuit. As an alternative, an encoded region designator may be used which selects the region that is to be encoded according to the bit rate of the transmission path, and the information on the designated region supplied from the outside. Also, a selector limiting the number of bits of the signal from the image signal input circuit may be provided, and when the bit rate of the transmission path is lowered, the number of bits of the input image may be adaptively switched.