in the following , one embodiment of the present invention will be described in detail with reference to the drawings . fig1 is a diagram generally showing the configuration of a recording system which is equipped with a control apparatus according to the present invention . in fig1 , a tv tuner 1 receives television broadcast waves supplied through an antenna or a cable , and only selects a broadcast wave from a broadcasting station corresponding to a channel specified by a channel specifying signal cs . the tv tuner 1 demodulates the broadcast wave to generate a received television signal which is supplied to each of a dvd recorder 2 and a hard disk recorder 3 . the dvd recorder 2 records video data and audio data based on the received television signal on a dvd ( not shown ). the dvd recorder 2 also reproduces video data and audio data recorded on a dvd , supplies the reproduced video data to a multi - screen display processing circuit 4 as video data dv 1 , and supplies the reproduced audio data to an audio selector 5 as audio data ad 1 . the dvd recorder 2 performs an operation indicated by a recording / reproducing operation instruction signal op 1 supplied from a manipulation switching control circuit 6 . for example , when the dvd recorder 2 is supplied with the recording / reproducing operation instruction signal op 1 indicative of a recording operation , the dvd recorder 2 starts the recording operation as mentioned above . on the other hand , when the dvd recorder 2 is supplied with the recording / reproducing operation instruction signal op 1 indicative of a reproducing operation , the dvd recorder 2 starts the reproducing operation as mentioned above . further , when the dvd recorder 2 is supplied with the recording / reproducing operation instruction signal op 1 indicative of a stopping operation , the dvd recorder 2 stops the reproducing operation or recording operation as mentioned above . the hard disk recorder 3 records the video data and audio data based on the received television signal on a magnetic disk as a built - in recording medium . the hard disk recorder 3 also reproduces video data and audio data recorded on the magnetic disk , supplies the multi - screen display processing circuit 4 with the reproduced video data as video data vd 2 , and supplies the audio selector 5 with the reproduced audio data as audio data ad 2 . the hard disk recorder 3 performs an operation indicated by a recording / reproducing operation instruction signal op 2 supplied from the manipulation switching control circuit 6 . for example , when the hard disk recorder 3 is supplied with the recording / reproducing operation instruction signal op 2 indicative of a recording operation , the hard disk recorder 3 starts a recording operation as mentioned above . on the other hand , when the hard disk recorder 3 is supplied with the recording / reproducing operation instruction signal op 2 indicative of a reproducing operation , the hard disk recorder 3 starts a reproducing operation as mentioned above . also , when the hard disk recorder 3 is supplied with the recording / reproducing operation instruction signal op 2 indicative of a stopping operation , the hard disk recorder 3 stops the reproducing operation or recording operation as mentioned above . the audio selector 5 selects one indicated by an audio output selection signal as from the audio data ad 1 and ad 2 , and supplies the display device 10 with an audio signal a out corresponding to the selected audio data . in this event , sound corresponding to the audio signal a out is output from a speaker ( not shown ) contained in the display device 10 . the multi - screen display processing circuit 4 generates a video signal for displaying an image based on the video data vd 1 and vd 2 on the display device 10 in a display mode specified by a display mode specifying signal mod , and supplies the display device 10 with this as a video signal v out . for example , when the display mode specifying signal mod indicates a dvd display mode , the multi - screen display processing circuit 4 generates the video signal v out for displaying an image based on the video data vd 1 over the entire screen of the display device 10 . when the display mode specifying signal mod indicates a hd display mode , the multi - screen display processing circuit 4 generates the video signal v out for displaying an image based on the video data vd 2 over the entire screen of the display device 10 . when the display mode specifying signal mod indicates a multi - screen display mode , the multi - screen display processing circuit 4 generates a video signal v out for displaying the image based on the video data vd 1 in a left half of the screen of the display device 10 and the image based on the video data vd 2 in a right half of the screen of the display device 10 . therefore , as shown in fig2 , a video image reproduced by and output from the dvd recorder 2 is displayed in a left half screen region er within the display screen 10 a of the display device 10 , and simultaneously , a video image reproduced by and output from the hard disk recorder 3 is displayed in a right half screen region el . also , in response to a selection frame display instruction supplied from the manipulation switching control circuit 6 , the multi - screen display processing circuit 4 generates the video signal v out which represents a single - color selection frame superimposed on the image around the periphery of a screen region ( er or el ) specified by the selection frame display instruction , as shown in fig2 . the remote control 7 has a variety of manipulation buttons on its manipulation panel for receiving a variety of instructing manipulation from the user . fig3 is a diagram showing a portion of the manipulation panel of the remote control 7 . as shown in fig3 , there are provided on the manipulation panel a group of numeral buttons for entering a variety of channels or numerical values for the tv tuner 1 and a cursor key ck for moving a cursor displayed on the screen of the display device 10 . the cursor key ck is made up of a right - direction key c r for moving the cursor in the right direction , a left - direction key c l for moving the cursor in the left direction , an upward direction key c u for moving the cursor in the upward direction , and a downward direction key c d for moving the cursor in the downward direction . there is provided on the manipulation panel a group of recording / replay buttons rsg which include a play button , a fast forward button , a rewind button , a pause button , a stop button , a record button , and the like . further , there are provided on the manipulation panel a dvd selection button d 1 for specifying the dvd recorder 2 as a target for manipulations and a hd selection button d 2 for specifying the hard disk recorder 3 as a target for manipulations . the remote control 7 generates a variety of manipulation signals corresponding to the variety of manipulation buttons depressed by the user for transmission to the manipulation signal receiver circuit 8 . the manipulation signal receiver circuit 8 receives the manipulation signals transmitted from the remote control 7 , and supplies them to the manipulation switching control circuit 6 . also , when the manipulation signal corresponds to a depression on a button in the group of numerical buttons ng , the manipulation signal receiver circuit 8 supplies the tv tuner 1 with a channel specifying signal cs corresponding to the depressed numeral . the manipulation switching control circuit 6 is set to a dvd manipulation mode when the manipulation signal includes a signal corresponding to a depression on the dvd selection button d 1 on the remote control 7 . on the other hand , the manipulation switching control circuit 6 is set to a hd manipulation mode when the manipulation signal includes a signal corresponding to a depression on the hd selection button d 2 on the remote control 7 . when the manipulation switching control circuit 6 is set to the dvd manipulation mode , the manipulation switching control circuit 6 supplies the dvd recorder 2 with a recorded image reproducing operation instruction signal op 1 corresponding to a depression on a button in the group of the recording / replay buttons rsg on the remote control 7 . in this event , the dvd recorder 2 is brought into an operating state specified by the recording / reproducing operation instruction signal op 1 . for example , when the user depresses the dvd selection button d 1 on the remote control 7 and subsequently depresses the play button in the recording / replay button group rsg , the dvd recorder 2 within the dvd recorder 2 and hard disk recorder 3 is set into a reproducing operation . on the other hand , when the manipulation switching control circuit 6 is set to a hd manipulation mode , the manipulation switching control circuit 6 supplies the hard disk recorder 3 with a recording / reproducing operation instruction signal op 2 corresponding to the depression on a button in the recording / replay button group rsg on the remote control 7 . in this event , the hard disk recorder 3 is set into an operating state specified by the recording / reproducing operation instruction signal op 2 . for example , when the user depresses the hd selection button d 2 on the remote control 7 and subsequently depresses the play button in the recording / replay button group rsg , the hard disk recorder 3 within the dvd recorder 2 and hard disk recorder 3 is set into a reproducing operation . here , when the dvd recorder 2 and hard disk recorder 3 are both set into the reproducing operation , the manipulation switching control circuit 6 first supplies the multi - screen display processing circuit 4 with a display mode specifying signal mod which specifies a multi - screen display mode . in response to this display mode specifying signal mod , the multi - screen display processing circuit 4 supplies the display device 10 with a video signal v out for displaying an image based on the video data vd 1 on the left half of the screen of the display device 10 , and an image based on the video data dv 2 on the right half of the screen of the display device 1 . in this way , the display device 10 displays the video image reproduced from the dvd recorder 2 within the image region el in the left half of the display screen 10 a . the display device 10 displays the video image reproduced from the hard disk recorder 3 within the screen region er in the right half of the display screen 10 a , as shown in fig2 . next , the manipulation switching control circuit 6 executes a control in accordance with a selection switching control flow as shown in fig4 . first , in fig4 , the manipulation switching control circuit 6 determines whether or not a manipulation signal supplied from the manipulation signal receiver circuit 8 includes a signal corresponding to a depression on the left - direction key c l as shown in fig3 ( step s 1 ). if the manipulation signal includes the signal corresponding to a depression on the left - direction key c l , as determined at step s 1 , the manipulation switching control circuit 6 supplies the multi - screen display processing circuit 4 with a selection frame display instruction for displaying the selection frame which surrounds the screen region el positioned in the left half of the display screen 10 a as shown in fig2 ( step s 2 ). a single - color selection frame sw is displayed on the periphery of the screen region el on the display screen 10 a by implementation of step s 2 , as shown in fig5 a . next , the manipulation switching control circuit 6 stores a dvd manipulation mode flag at logical level 1 , indicative of the dvd manipulation mode , in a built - in register ( not shown ), and supplies the audio selector 5 with an audio output selection signal as for selecting audio data ad 1 ( step s 3 ). the execution of step s 3 causes the manipulation switching control circuit 6 to enter the dvd manipulation mode , so that the dvd recorder 2 is supplied with a recording / reproducing instruction signal ( op 1 ) corresponding to a variety of recording / reproducing manipulations through the remote control 7 . in other words , only the dvd recorder 2 within the dvd recorder 2 and hard disk recorder 3 is subjected to manipulations through the remote control 7 . further , through the execution of step s 3 , sound based on the audio data ad 1 reproduced and output from the dvd recorder 2 is output from the speaker built in the display device 10 . on the other hand , if the manipulation signal does not include a signal corresponding to a depression on the left - direction key c l , as determined at step s 1 , the manipulation switching control circuit 6 determines whether or not the manipulation signal includes a signal corresponding to a depression on the right - direction key c r as shown in fig3 ( step s 4 ). if the manipulation signal does not include a signal corresponding to a depression on the right - direction key c r , as determined at step s 4 , the manipulation switching control circuit 6 returns to step s 1 to repeatedly execute the operation as described above . if the manipulation signal includes a signal corresponding to a depression on the right - direction key cr as determined at step s 4 , the manipulation switching control circuit 6 supplies the multi - screen display processing circuit 4 with a selection frame display instruction for displaying the selection frame surrounding the screen region er positioned in the right half of the display screen 10 a as shown in fig2 ( step s 5 ). the single - color selection frame sw is displayed on the periphery of the screen region er on the display screen 10 a by implementation of step s 5 , as shown in fig5 b . next , the manipulation switching control circuit 6 stores the hd manipulation mode flag at logical level “ 1 ”, indicative of the hd manipulation mode , in the built - in register ( not shown ), and supplies the audio selector 5 with the audio output selection signal as for selecting the audio data ad 2 ( step s 6 ). the execution of step s 6 causes the manipulation switching control circuit 6 to enter the hd manipulation mode , so that the hard disk recorder 3 is supplied with a recording / reproducing instruction signal ( op 2 ) corresponding to a variety of recording / reproducing manipulations through the remote control 7 . in other words , only the hard disk recorder 3 within the dvd recorder 2 and hard disk recorder 3 is subjected to manipulations through the remote control 7 . further , through the execution of step s 6 , sound based on the audio signal ad 2 reproduced from the hard disk recorder 3 is output from the speaker built in the display device 1 . after the execution of step s 3 or s 6 , the manipulation switching control circuit 6 determines whether or not the manipulation signal supplied from the manipulation signal receiver circuit 8 includes a signal corresponding to a depression on the stop button in the recording / replay button group rsg as shown in fig3 ( step s 7 ). if the manipulation signal does not includes a signal corresponding to a depression on the stop button as determined at step s 7 , the manipulation switching control circuit 6 returns to step s 1 to repeatedly execute the operation as described above . on the other hand , if the manipulation signal includes a signal corresponding to a depression on the stop button , as determined at step s 7 , the manipulation switching control circuit 6 exits the selection switching control flow as shown in fig4 , and proceeds to the execution of a main control routine ( not shown ). with the configuration as described above , the user can just select one of the screen regions er and el displayed within the display screen 10 a with the right - direction key cr or the left - direction key cl on the remote control 7 to set an image information reproducing apparatus ( dvd recorder 2 or hard disk recorder 3 ), which is supplying an image displayed in the selected screen region , as a target for the operation control . thus , the user can correctly manipulate an image information reproducing apparatus which is supplying a desired image even without recognizing a correspondence relationship between a plurality of images displayed on the screen and respective image information reproducing apparatuses which are supplying these images . in the foregoing embodiment , the frame - shaped selection frame sw is displayed around the periphery of a selected one of the screen regions er and el to visually inform the selected screen region . the shape of the selection frame sw , however , is not limited to that shown in fig5 a or 5 b . for example , a selection mark sm may be displayed in a peripheral portion of a selected screen region as shown in fig6 . in essence , an informing image is only required to be displayed in a peripheral portion of a selected screen region for visually informing the selected screen region . also , while in the foregoing embodiment , the screen regions ( er , el ) are switched through a depression on the left - direction key c l and right - direction key c r , the remote control 7 may be provided with a single screen switching button , such that a selected screen region is switched from one to the other each time the screen switching button is depressed . also , while in the foregoing embodiment , the selection frame sw is displayed at all times as an informing image around the periphery of a selected screen region , the selection frame sw may be erased by the user through a manipulation on the remote control 7 . for example , an instruction for erasing the display of the selection frame sw may be transmitted in response to simultaneous depressions on the dvd selection button d 1 and hd selection button d 2 provided on the remote control 7 . in this event , the multi - screen display processing circuit 4 erases the selection frame sw in response to the display erase instruction . also , while the foregoing embodiment has been described in connection with two image information reproducing apparatuses , i . e ., the dvd recorder 2 and hard disk recorder 3 for simultaneously reproducing images , such image information reproducing apparatuses may be three or more . in essence , respective images reproduced by n ( n is a natural number equal to or larger than two ) image information reproducing apparatuses may be simultaneously displayed in n screen regions , one by one , within a display screen , such that the user is allowed to manipulate only an image information reproducing apparatus which is the source of an image displayed in a screen region selected through a manipulation on the remote controller . this application is based on a japanese patent application no . 2003 - 157607 which is hereby incorporated by reference .