An encoder and decoder to encode one or more input signals into a scalable codec and to decode the scalable codec, and encoding and decoding methods using a bitstream with a layered structure in the scalable codec change a top coding bit rate to encode the input signals according to a network status, and the bitstream is decoded by analyzing the top coding bit rate included in the bitstream. The common thin film transistor has a common gate electrode, a common source electrode and a common drain electrode. At least one display device, such as an LCD, is hingedly connected to the frame support.