A method for processing multimedia content independently of a specific OS in a data processing apparatus comprising an input apparatus for data, an output apparatus (171, 181) for data, a storage section to store process modules, an instruction issuing section to issue instructions, and a calculation processing section to perform processes using said process modules, said method comprising the steps of: providing an interface layer including a general-purpose system interface and a data access module manager with data access modules (271, 405), whereby the interface layer uses a generalised interface to provide higher layers with functions provided from an OS-provided system interface and the interface performs the same functions independently of different platforms; specifying, based on a first instruction issued from said instruction issuing section, at least one process needed to process said data input from said input apparatus or to be output by said output apparatus (171, 181); generating a process module needed for said specified process in said storage section; allocating to said process module a data access module (271, 405) for inputting data from said input apparatus or outputting data to said output apparatus (171, 181), and a data processing module (241, 401) for performing said specified process for data input or to be output via said data access module (271, 405), said data access module (271, 405) accessing a device driver via the OS's system interface using platform dependent functions to input or output data from a hardware device, and said data processing module (241, 401) being situated in the higher layers using only platform independent interfaces; using a link module (410, 420) to connect the necessary number of said process modules with each other to generate a process flow to perform said process in said storage section; calculating, based on a bit rate notified from said instruction issuing section and a block size as a unit of processes, a scheduled time needed for the next process module and registering said time in a stream table (1100, 2000) to specify a data processing management module and a sequence of processes in a first processing section of said process module; inputting data supplied from said input apparatus to a start of said process flow based on a second instruction issued from said instruction issuing section and causing said calculation processing section to perform said process flow registered in said stream table (1100, 2000); and causing said output apparatus (171, 181) to output a process result of said process flow performed. providing an interface layer including a general-purpose system interface and a data access module manager with data access modules (271, 405), whereby the interface layer uses a generalised interface to provide higher layers with functions provided from an OS-provided system interface and the interface performs the same functions independently of different platforms; specifying, based on a first instruction issued from said instruction issuing section, at least one process needed to process said data input from said input apparatus or to be output by said output apparatus (171, 181); generating a process module needed for said specified process in said storage section; allocating to said process module a data access module (271, 405) for inputting data from said input apparatus or outputting data to said output apparatus (171, 181), and a data processing module (241, 401) for performing said specified process for data input or to be output via said data access module (271, 405), said data access module (271, 405) accessing a device driver via the OS's system interface using platform dependent functions to input or output data from a hardware device, and said data processing module (241, 401) being situated in the higher layers using only platform independent interfaces; using a link module (410, 420) to connect the necessary number of said process modules with each other to generate a process flow to perform said process in said storage section; calculating, based on a bit rate notified from said instruction issuing section and a block size as a unit of processes, a scheduled time needed for the next process module and registering said time in a stream table (1100, 2000) to specify a data processing management module and a sequence of processes in a first processing section of said process module; inputting data supplied from said input apparatus to a start of said process flow based on a second instruction issued from said instruction issuing section and causing said calculation processing section to perform said process flow registered in said stream table (1100, 2000); and causing said output apparatus (171, 181) to output a process result of said process flow performed.