the known data output unit 487 inserts the predefined known data into the position of the transport frame encoded by the encoder 485 that corresponds to the known symbols obtained according to the identification sign fig4 illustrates the structure of a general mpeg 2 transport stream packet and fig5 illustrates the structure of an mpeg 2 transport stream packet that includes an adaptation field to which stuff bytes are added according to an embodiment of the present general inventive concept referring to fig4 the general mpeg 2 transport stream is composed of a ts header part of 4 bytes and an adaptation field or payload data of 184 bytes referring to fig5 according to the mpeg 2 transport stream of the present general inventive concept an adaptation field of u201c n u201d bytes is located after the header part of 4 bytes and payload data of u201c 184 n u201d bytes is located after the adaptation field the fifth and sixth bytes that is the first two bytes of the adaptation field constitute control information bits that include length information of the adaptation field and stuff bytes according to an embodiment of the present general inventive concept are inserted into the seventh byte of the transport stream that is.