fig1 shows the basic components of a data processing apparatus such as may be used for the encoding and recording of programmes to a dvd recording medium ( disk ) 10 . the apparatus consists of a central processor ( cpu ) 12 coupled in a conventional manner with random - access memory ( ram ) 14 and read - only memory ( rom ) 16 via an address and data bus 18 . an external interface ( ext i / f ) 20 represents the apparatus connection with external data sources . in the case of a domestic video / audio recorder , the interface will provide the connection and reception means for the source of video and audio signals to be recorded ( such as from a satellite receiver ). this specific situation shows two sources 28 providing two simultaneous a / v input streams . these sources may for example be separate video tuners , internal or external to the dvd recorder . they may also be separate programmes conveyed within a single digital video broadcast multiplex , for example in mpeg2 transport stream format . also coupled with cpu 12 , memories 14 , 16 and interface 20 via the bus 18 are one or more user input means ( uip ) 22 and a display 24 . for a domestic a / v recorder apparatus they may comprise user control buttons and an led or like display on the apparatus front panel . a further component is an interface to the storage medium , in this example an optical disk recording and playback unit ( disk r / w ) 26 . unit 26 provides both the physical means to load and read and write data from and to the disk 10 and an internal set of operational protocols for reading & amp ; writing data formatted according to a predetermined standard . as will be well understood , the protocol handling of unit 26 may be effected by an internal slave processor with associated memory ( not shown ) with only higher - level control implemented by cpu 12 , or these functions may be handled directly by cpu 12 with reference to programs held in rom 16 and executed from there , or periodically reloaded to ram 14 . the basic construction and operation of such apparatuses are well - known to those skilled in the art and need not be described here for an understanding of the present invention . the data on all dvd and cd disks is organized in a single spiral track . in the case of dvd read - only media , the data is a series of pits in the media , while for recordable re - writable systems such as dvd + rw there is a single spiral groove where recorded marks are written . actual data marks are barely visible to the human eye , but are still easily detected by a drive &# 39 ; s optics and electronics . each programme or section recorded on a dvd follows immediately the previous programme / section on the spiral track . no gaps are allowed between programmes for the disk to meet the requirements for playback on a standard dvd player . the dvd video specification and consequently the dvd + rw system does , however , allows for “ multi angle ” playback and recording . this allows disks to be recorded with , for example , action sequences or sport events in such a way that , during playback , the viewer is able to watch the action from a number of different views or camera angles and can pick and choose between them during playback . to enable this “ multi angle ” function the dvd video specification provides a protocol that allows multiple video streams to be created on the disk . this is done by multiplexing small sections of each video stream , each obtained from a different camera filming the same scene / event , within one mpeg2 video stream . when a dvd player encounters a multi - angle section of video , it simply reads the section for the angle it is displaying and then skips over the subsequent sections relating to other angles until the next section containing video for its angle is reached . in this way video from a single angle can be viewed uninterrupted . furthermore , the angle can be changed by the viewer as desired , the player skipping to and playing the next video section for the new selected angle and all subsequent sections of this angle , again skipping all other angles . a further feature of the multi angle playback feature of the dvd video specification is the possibility of recording a different audio track for each camera angle . this feature , though very rarely used , allows a programme marker to improve atmosphere for a particular scene , or allow for an angle showing the “ bench ” or technical area in the recording of a football match wherein coaching instructions etc . can be heard . because the dvd video standard was designed to be used as a medium for pre - recorded movies and programmes , it was not envisaged to record two or more programmes simultaneously ( particularly as this is not possible with conventional vhs tape and therefore was possibly not regarded as an essential feature when designing dvd playback apparatus ). however , such a feature is obviously desirable on a dvd video recorder . fig2 a and 2 b give an example why the inability to leave gaps between programmes makes it impossible to record programmes simultaneously simply by starting recording one stream at one point on the disk , and starting another stream at a different point later on the disk . fig2 a shows a bar 1 representing the disk capacity of a dvd on which there is being recorded two programmes from different tuners simultaneously . the first programme is represented by the first video stream 2 and the second programme is represented by the second video stream 3 . the first stream 2 is being recorded starting at the front of the disk and the recording of the second stream 3 is started at a position representing one hour into the disk . fig2 b shows the situation after 45 minutes , where , at this point the first program ends . the first stream 2 ends 45 minutes into the disk and the second stream 3 is now 1 hour 45 into the disk . therefore a blank 15 - minute gap 4 is left between the end of the first stream and beginning of the second . such a gap is not allowed if dvd compatibility is to be maintained . however , it is also impossible to start the recording of the second stream in exactly the right place as there is no way for the recorder to know the exact length of the first stream to be recorded ( this is further complicated by the fact that file size is not only dependent on time ). this problem is addressed in the novel apparatus of fig1 by using the multi angle feature of the dvd video specification to record both simultaneous a / v streams into the same mpeg2 programme stream as if they where both constituents of a multi angle section of video . this is done by multiplexing small sections of each video stream within the single mpeg2 stream . fig3 shows a bar 30 representing again the disk capacity of a dvd during playback of a programme recorded simultaneously with another using the multi - angle feature . the sections marked 1 represent the first programme and 2 the second programme . when the player ( not necessarily the machine which made the recording ) first encounters the multiplexed section , it plays the first section it encounters containing video ( and audio ) for the programme selected ( say the first a / v stream 1 ) and then skips any sections relating to other streams / programmes until it encounters the next relevant section . the recorder arranges that ( i ) both programmes will appear as separate entries in the table of contents on the dvd menu , and ( ii ) when one of these programmes is selected for playback the player will play the same stream but from different “ angles ” as appropriate . to ensure that the user is kept unaware of the recording method , the “ change angle ” button on the remote control can be disabled during playback of any programmes recorded in this way . this is achieved by the recorder placing appropriate values in certain dvd video structures . this solution therefore addresses the problem of not knowing the duration of the first programme because as soon as one programme finishes , the other can be continued to be recorded , just as a normal non - multi angle stream , as illustrated in fig4 ( assuming that only two programmes were being recorded simultaneously ). this solution also addresses the problem of too much head movement as now both or all programmes are recorded in one continuous stream . another recording can be started at any time . three or more programmes can be recorded simultaneously in this way if the source data is available . if one of the programmes is subsequently to be erased , it would normally be difficult to arrange for the recorder to free the space where the erased programme is interleaved as one view within a multi - view programme . by aligning the angle sections on ecc blocks when recording the original two programmes , however , the novel recorder makes it easy for the space occupied by a recording to be re - used without requiring the other angle to be modified . fig5 shows the situation after programme 2 within the recording of fig3 has been erased and overwritten by programme 3 . as mentioned above , the invention is particularly applicable to the dvd standard currently in wide use , but can be applied in future systems that may replace or extend dvd . these and other variations and modifications will be readily envisaged by the skilled reader , and which can be made without departing from the spirit and scope of the invention .