embodiments of the present invention will be described in detail below with reference to the accompanying drawings . first , descriptions will be made as to the structure and operations of a multimedia processing section in accordance with an embodiment of the present invention provided on a receiving side that receives bitstreams with time stamps dedicated to ipmp processing ( hereafter called “ its ”) appended thereto . [ 0045 ] fig6 shows a structure of a multimedia processing section at a receiving side in accordance with an embodiment of the present invention . referring to fig6 a bitstream receiving section 601 receives bitstreams that are multiplexed from a server . a demultiplexer 602 demultiplexes the multiplexed bitstreams , and extracts each of the bitstreams . here , each of the extracted bitstreams is independently stored in a buffer for bifs decoding 603 , a buffer for media decoding 604 ( wherein video and audio are generally called “ media ” in the present embodiment ), and a buffer for ipmp decoding 605 , respectively . the stored bitstreams are decoded by a bifs decoder 608 , a media decoder 609 and an ipmp decoder 610 , respectively . in some cases , as described below , decoding processings for bifs and each of the media may be prohibited by the ipmp processing . also , the demultiplexer 602 outputs time stamps for media streams and ipmp streams , respectively . the multimedia processing section also includes a media dts detector 607 , a media cts detector 616 , an ipmp dts detector 611 and an ipmp cst detector 612 . in the present embodiment , an its detector 606 extracts time stamps dedicated to ipmp processing which are referred to as its , and control decoding timings of the ipmp decoder 610 . decode time stamps ( dtss ) and composition time stamps ( ctss ) for the media and the ipmp are compared by a dts comparator 613 and a cts comparator 617 , respectively , to check whether or not the dtss and the ctss of the media and the ipmp are in consistent with each other , respectively . an and gate 619 provides logical products ( ands ) under conditions when the dtss and ctss of the media and the ipmp are in consistent with each other , respectively . accordingly , the and gate 619 outputs a true value “ 1 ” only when the dtss and ctss for the media are in consistent with the dtss and ctss for the ipmp , respectively . in other words , with the structure described above , a determination can be made as to whether or not the dtss and ctss for the media are completely in consistent with the dtss and ctss for the ipmp , respectively . a sync - controller 620 governs decoding timing control for the decoders , synchronization control among the media and reproduction timing control . when the dtss and ctss for the media are completely in consistent with the dtss and ctss for the ipmp , respectively , and assumes that updates of the ipmp data correspond to the corresponding access units of the media . as a more specific example , let us consider a situation where the media data has been scrambled , and its descrambling key changes periodically . in this case , a normal reproduction becomes impossible unless each of the access units of the media and the update timing of the descrambling key are accurately defined . the sync - controller 620 monitors outputs of the dts comparator 613 and the cts comparator 617 and controls the timings . more specifically , sync - controller 620 controls timings for descrambling the media data that are supplied to the respective decoders and update timings of the descrambling key . a bifs composition buffer 614 composes scene information that have been decoded by the bifs decoder . a media composition buffer 615 temporarily stores a specified amount of decoded image frames and audio data . when the ipmp method uses only a data scrambling , each of the media is composed ( re - constructed ) by a compositor 618 without a further change , and displayed or reproduced by a renderer 621 . a monitor apparatus 623 provides a final rendering on the image ( or video ) media ( for display ), and a speaker apparatus 624 provides a rendering on the audio media ( for audio reproduction ). when the ipmp method uses not only a data scrambling but also a control for reproduction or non - reproduction of the media , display and reproduction of each of the media must be accurately started ( or stopped ) at intended timings . in this case also , like the above case in which only the data scrambling is used , display and reproduction of each of the media can be accurately started ( or stopped ) in units of access units through controlling the compositor 618 and the renderer 621 by the sync - controller 620 based on the comparison results of the dts comparator 613 and the cts comparator 617 . [ 0056 ] fig1 shows a flow chart for describing a descrambling processing . when decoding is started ( step s 101 ), the its detector 606 detects itss ( step s 102 ). then , the ipmp decoder 610 decodes the ipmp data with the timings of the itss detected ( step s 103 ). the decoding processing of the ipmp data may correspond , when a scramble key itself is multi - scrambled ( encrypted ), to a processing to extract the scramble key to decode the media data . then , dtss and ctss of the ipmp data are detected by the ipmp dts detector 611 and the ipmp cts detector 612 , respectively ( step s 104 ). dtss and ctss of each of the media data are also detected by the media dts detector 607 and the media cts detector 617 , respectively ( step s 105 ). then , the dtss and ctss of the ipmp data and the dtss and ctss of each of the media are compared by the dts comparator 613 and the cts comparator 617 , respectively . when they are not in consistent with each other , a determination is made that the scramble key has not been updated , and the media data is descrambled with the current scramble key , and decoded ( step s 107 ). on the other hand , when they match with each other , a determination is made that the scramble key has been updated , the scramble key is updated ( step s 108 ), and then the media data is descrambled and decoded ( step s 109 ). then , the compositor 618 performs a composition processing and the renderer 621 performs a rendering processing ( step s 110 ), and these processings are repeated until the end of the data ( step s 111 ). it is noted that , when the ipmp method uses not only a data scrambling but also a control for reproduction or non - reproduction of the media , additional display and reproduction controls are performed in step s 110 . next , descriptions will be made as to the structure and operations of a multimedia processing section in accordance with an embodiment of the present invention provided on a transmission side that transmits bitstreams with itss appended thereto . [ 0064 ] fig7 shows the structure of a multimedia processing section on a transmission side in accordance with the present embodiment . referring to fig7 a media encoder 701 performs an encoding for each of the media data , which is suitable for each of the media . for example , when the media data is image data , the media encoder 701 performs an encoding on the media data according to mpeg - 4 visual ( iso / iec 14496 - 2 ), and performs a scrambling processing with a scramble key . a dts / cts generator 702 generates time stamps ( dtss and ctss ) according to reproduction conditions of each of the media . an ipmp encoder 703 performs an encoding processing on the ipmp information . the encoding processing on the ipmp data may corresponds to a processing to scramble ( encrypt ) the scramble key itself . a dts / cts buffer 704 temporarily stores time stamps ( dtss and ctss ) that are generated by the dts / cts generator 702 . a sync - controller 705 receives inputs of the dtss and ctss generated by the dts / cts generator 702 and the ipmp information that is encoded ( scrambled or encrypted ) by the ipmp encoder 703 , and performs a synchronizing control for reproducing each of the media , and also controls generation of its information to be described below . an its generator 706 generates its information for each of access units according to an instruction from the sync - controller 705 based on the dtss and ctss stored in the dts / cts buffer 704 . a packetizer 707 performs an appropriate packetizing processing using the encoded media information and ipmp information , the dtss , the ctss , and the its information . since the values of the dtss and ctss of the ipmp are the same as those of the media information , the dts / cts generator 702 generats dtss and ctss for the ipmp . at the time of the packetizing processing , a header generation section 709 adds headers , and a multiplexer 708 performs a final multiplexing . then a bitstream transmission section 710 transmits the data multiplexed by the multiplexer 709 . [ 0072 ] fig8 shows a timing chart of time stamps in accordance with an embodiment of the present invention . [ 0073 ] fig8 shows video streams as one example of media streams , but the media streams can be of any type . what is to be focused on is the relations between the dtss and ctss of the video and dtss and ctss of the ipmp . for example , when a video access unit 1 ( video au1 ) has a decode start timing dts1 and a composition start timing cts1 , a dts and a cts of the ipmp stream for this access unit have the same values as the dts1 and the cts1 , respectively . in other words , by making the values of dtss and ctss for each video access unit and each ipmp access unit equal to one another , the video access unit and the ipmp access unit can be correlated to each other . accordingly , dtss and ctss for the ipmp streams do not indicate decoding and composition timings of themselves , but are used for correlating each of the media streams and each of the access units . in the meantime , decoding ( for example , descrambling a scrambled encryption master key that is used to descramble the video bitstreams ) timings of the ipmp streams can be controlled in units of access units of the ipmp streams themselves by itss that are additionally defined . another embodiment of the present invention in which an electronic watermark technique is applied will be described below with reference to the accompanying drawings . in the present embodiment example , an electronic watermark technique is used to embed scramble keys for media data in ipmp data , and itss indicate processing timings for extracting ( decoding ) the scramble keys embedded by the electronic watermark technique . [ 0078 ] fig9 shows a timing chart of time stamps in accordance with the other embodiment . dtss and ctss shown in fig9 are used for the purpose of indicating mutual relations among the access units of the media streams and the ipmp streams . in the embodiment described with reference to fig8 the present invention is applied to a system that uses an encryption scheme , for example . however , when media bitstreams have been scrambled , the media bitstreams need a descrambling processing , and then a decoding processing and a composing processing to be performed . accordingly , a relation its ≦ dts ≦ cts is established ( see fig8 ). when the time stamps its , dts and cts are equal to one another , such relation indicates an ideal state where all of the processings can be executed in no ( zero ) time . accordingly , the ipmp processing controls operations of the decoder ( i . e ., the ipmp processing has the decoder perform a decoding processing or not perform a decoding processing ). on the other hand , in the system using an electronic watermark technique , electronically watermarked data are extracted from decoded bitstreams , and therefore the decoding processing must be performed first , and then the ipmp processing controls operations of the compositor ( i . e ., the ipmp processing has the compositor perform a composition processing or not perform a composition processing ). in view of the above , the time stamps have a relation dts ≦ its ≦ cts . fig9 shows a timing chart in this case . in this manner , in accordance with the present invention , time stamps exclusively used for ipmp processings ( i . e ., itss ) are additionally provided , such that timings of itss can be flexibly controlled based on dtss and ctss for the media streams . the embodiments described above ( e . g ., the circuits indicated by block diagrams in fig6 and 7 ) may be realized by hardware . however , the entire system in accordance with the embodiments of the present invention can be realized by software . also , in the embodiments described above , video and audio data are handled as examples of multimedia data . however , the present invention is also applicable to texts and graphics data . as described above , in accordance with the embodiments of the present invention , a variety of ipmp processings are reliably synchronized , and can be flexibly composed . the present invention may be applicable to a system that is composed of a plurality of apparatuses ( for example , a host computer , interface devices , readers , printers and the like ), or to a unit that is composed of a single apparatus ( for example , a copy machine , a facsimile machine or the like ). the present invention can be achieved by having a storage medium that stores program codes of software that realize the functions of the embodiments described above supplied to a system or an apparatus , and by having a computer ( or a cpu or an mpu ) of the system or the apparatus read and execute the program codes stored in the storage medium . in this case , the program codes themselves that are read from the storage medium realize the functions of the embodiment of the present invention , and the storage medium that stores the program codes constitute the present invention . the storage medium to supply the program codes may be , for example , a flexible disk , a hard disk , an optical disk , an optical magnetic disk , a dvd , a cd - rom , a cd - r , a magnetic tape , a nonvolatile memory card , or a rom . furthermore , the present invention is applicable not only when the program codes read by a computer are executed to realize the functions of the embodiments , but also when an operating system that operates on the computer performs a part or all of the actual processing based on the instructions contained in the program codes and thereby realizes the functions of the embodiments . moreover , the present invention is also applicable when the program codes that are read from the storage medium are written on a memory of an expansion board inserted into a computer or of an expansion unit connected to a computer , and a cpu provided on the expansion board or on the expansion unit performs a part or all of the actual processing based on the instructions contained in the program codes and thereby realizes the functions of the embodiments . as described above , in accordance with the embodiments of the present invention , synchronization control information appended to media data and synchronization control information appended to ipmp information are synchronized , and information that indicates timings to start processings that are defined by the ipmp information are generated in association with the respective synchronization control information . as a result , processings for intellectual property management can be flexibly performed . while the description above refers to particular embodiments of the present invention , it will be understood that many modifications may be made without departing from the spirit thereof . the accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention . the presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive , the scope of the invention being indicated by the appended claims , rather than the foregoing description , and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein .