id data size data 2 packet command command id data size data packet data and 3 null command the data size in the single command may vary according different types of commands takeing a viewport command for instance the data size in each viewport command is the same and in fact represents two numbers namely length and width the length of packet data in a packet command varies with data contents for example for a common loadtexture command apart from length and width information data thereof also includes color standard like rgb888 the length of packet data containing texture is determined by data contents which are length width and color standard a null command on the other hand does not contain any attached information for example a finish command represents completion of an operation while containing no attached information in this embodiment multimedia commands may be completely transmitted in form of the three foregoing commands which may contain data such as pixel data for video reconstruction position and offset for video reconstruction sequence for video reconstruction and data for audio reconstruction to effectively distinguish command types from one another command ids may be classified according to types of apis namely openvg opengl es opensl es and openmax upon reception of multimedia commands packaged in the predetermined format the command parser 421 distributes the commands according to the command ids thereof and transmits the commands to corresponding client drivers in the second driver set 422 fig5 shows a flow chart to clearly explain determination and distribution steps of the aforesaid commands according to the invention in step 51 a digital television receives a multimedia command in a predetermined format in step 52 the command.