A portable device for processing a multimedia signal is provided. The portable device includes: a signal receiver to receive a multimedia signal from a mobile terminal, the multimedia signal being received in the mobile terminal from a service providing server; a decoding-related information generation unit to generate decoding-related information which is related to at least one of a codec and a resolution; a decoder to decode the multimedia signal according to the decoding-related information, and to generate multimedia information; and a multimedia information transmitter to transmit the multimedia information to an external display device.