JP2002281455A - Reproducing device and recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the degree of freedom in an FF(fast forwarding) or REW(rewinding) and also to improved use convenience of image search. SOLUTION: In a recording and reproducing device 1 for performing video recording of broadcast video on a randomly accessible recording medium 10 and reproducing the video, the time interval of image change in an FF or REW mode and the display time of a still picture to be displayed each time an image changes are inputted from an inputting part 13, and a recorded information controlling part 9 controls a video output in the FF or REW mode on the basis of a set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for reproducing moving image data recorded on a recording medium.

[0002]

2. Description of the Related Art In recent years, with the development of digital video / audio compression technology such as MPEG2 and the performance improvement of a randomly accessible storage medium represented by a hard disk drive,
2. Description of the Related Art Program recording / reproducing apparatuses capable of recording, storing, and reproducing digitally compressed video of several hours to several tens of hours of television broadcasting programs such as terrestrial broadcasting and satellite broadcasting in a large-capacity storage medium are being put into practical use.

[0003] One of the features of recording and playback using a random access storage medium is that it is not necessary to record recorded video and audio data in a physically continuous area. It is possible to record continuously in the free space that has been set, and to easily realize functions such as freely changing the order of programs regardless of the recording time order, playing back, and jumping to any area instantly. Can be.

[0006] In MPEG, image compression is usually performed with a plurality of frames as one unit, and the concept of GOP (Group Of Picture) is used as the unit. One GOP is usually 0.5 seconds (15
Frame), and the frame type is an I-picture in which a moving image frame is predictively coded using image data in a frame, and a prediction type is coded using image data of a preceding frame data. P picture, and a B picture that is predictively coded using the image data of the previous and next frames.
It has P independence. The moving image information is recorded in units of GOP, and is decoded via an MPEG video decoder during reproduction and displayed on a screen.

[0005] In the case of FF (fast-forward playback), image data of only an I picture recorded at the beginning of each GOP is read, and the read image data is decoded via an MPEG video decoder and displayed. At this time, since the discrete I picture is reproduced, an image that changes once every few seconds is displayed on the screen, such as frame-by-frame advance. The same applies to REW (early rewind playback), in which only I-pictures recorded at the beginning of a GOP are played back one after another in the reverse direction.

Therefore, for example, when performing FF or REW at 1 × speed, only all I pictures are successively reproduced, and when performing FF or REW at 2 × speed, every other G picture is reproduced.
When only the I pictures of the OP are successively reproduced and FF or REW is performed at triple speed, only the I pictures of every third GOP are successively reproduced.

[0007]

In the conventional recording / reproducing apparatus, the change interval of the screen in FF or REW is constant and cannot be changed. That is, in the conventional recording / reproducing apparatus, the double speed at which the FF or the REW can be performed is predetermined and cannot be changed. Therefore, the recording / reproducing device:
If it is set that 1x speed, 2x speed, and 3x speed FF or REW is possible, 1x speed or 2x speed
FF or REW at double speed or triple speed can be performed, but FF or REW at other double speeds cannot be performed.

The present invention solves such a conventional problem, and allows a user to freely control the degree of fast-forward and / or fast-rewind during fast-forward playback and / or fast-rewind playback of moving image data. It is an object of the present invention to provide a playback device that can be set.

[0009]

In order to achieve the above object, a first aspect of the present invention (corresponding to claim 1) is to fast-forward playback and / or reproduce the moving image data on a recording medium on which the moving image data is recorded. In a reproducing apparatus for performing fast-rewind playback, an input section in which a degree of fast-forward and / or fast-rewind can be set by a user, and the fast-forward playback based on the fast-forward and / or fast-rewind degree input to the input section. And / or a control unit for controlling fast rewind reproduction.

According to a second aspect of the present invention (corresponding to claim 2), the control section performs the control by changing a display time interval of each frame without changing a frame to be displayed. The playback device according to item 1.

According to a third aspect of the present invention (corresponding to claim 3), the control unit changes the frame to be displayed and performs the control by changing the display time interval of each frame.
Of the present invention.

According to a fourth aspect of the present invention (corresponding to claim 4), a storage section for storing a plurality of degrees of the fast-forward and / or fast-rewind as set values, and a plurality of storage sections stored in the storage section. A selection unit that allows a user to select any one of the set values, wherein the control unit performs the control based on the set value selected by the user. is there.

According to a fifth aspect of the present invention (corresponding to claim 5), there is provided a normal playback section for normally playing back the moving image data, and a user can input a request for fast forward playback or fast rewind playback of the moving image data. And when the user inputs the request when the moving image data is normally reproduced, from the image data of the frame displayed at that time, or immediately before or immediately after the image data. From the in-frame image data, the control unit:
The playback device according to the first aspect of the present invention, wherein the moving image data is played back fast forward or fast backward.

According to a sixth aspect of the present invention (corresponding to claim 6), a normal reproduction section for normally reproducing the moving image data and a second input section for allowing a user to input an instruction for normal reproduction of the moving image data are provided. When the user inputs the instruction when the moving image data is being played back in fast-forward or fast-rewind mode, the normal playback unit uses the moving image data from the image data of the frame displayed at that time. Is a playback apparatus according to the first aspect of the present invention, which normally plays back a video.

According to a seventh aspect of the present invention (corresponding to claim 7), each of the frames to be fast-forwarded or fast-rewinded is a frame displayed on a screen having a plurality of display areas. The playback device according to the first aspect of the present invention, wherein each of the frames is sequentially displayed in another display area.

According to an eighth aspect of the present invention (corresponding to claim 8), when the frame is displayed in all of the plurality of display areas, and when another frame is displayed,
The playback device according to a seventh aspect of the present invention, wherein the control unit displays each frame in the display area where the frame is displayed for a substantially constant time and uses all of the plurality of display areas cyclically. It is.

According to a ninth aspect of the present invention (corresponding to claim 9), a normal reproduction section for normally reproducing the moving image data and a selection section for allowing a user to select any one of the frames displayed in the plurality of display areas When a plurality of frames are displayed in the plurality of display areas, when the user performs the selection, from the image data of the selected frame, or immediately before or immediately after the image data The reproduction apparatus according to the seventh or eighth aspect of the present invention, wherein the normal reproduction section reproduces the moving image data normally from the in-frame image data.

A tenth aspect of the present invention (corresponding to claim 10) is:
In a reproducing apparatus for reproducing the moving image data on a recording medium on which moving image data is recorded, a predetermined frame of a plurality of image data constituting the moving image data is stored in a storage unit, and the stored frames are stored. Is a playback device provided with a control unit that simultaneously displays all the files simultaneously.

The eleventh invention (corresponding to claim 11) provides:
A playback device according to any one of the first to tenth aspects of the present invention, a moving image recording unit that records the moving image data on the recording medium, and recording of all or a part of each image data that constitutes the moving image data A time information recording unit that records the time of the image data to be reproduced on the recording medium in association with each of the image data, and the control unit determines a time at which the image data to be reproduced is recorded based on the image data related to the time. This is a recording / reproducing device that displays the frame together with the frame.

The twelfth invention (corresponding to claim 12) provides:
A time counting unit that counts time, wherein the time information recording unit records, on the recording medium, a time counted by the time counting unit when each of the image data is recorded as the recording time. Is a recording / reproducing apparatus according to the present invention.

A thirteenth invention (corresponding to claim 13) is:
The moving image data is broadcast data, and the moving image data includes information on the time at which all or some of the image data constituting the moving image data is reproduced,
A receiving unit that receives the moving image data and an electronic program guide related to the moving image data; a time when the moving image data is broadcast in the electronic program guide received by the receiving unit; and all or a part of each image data A time calculating unit that calculates the time at which each of the image data is recorded, based on the information about the time at the time of reproduction.The time information recording unit is configured to calculate the time of the image data calculated by the time calculating unit. The recording / reproducing apparatus according to an eleventh aspect of the present invention, wherein a recording time is recorded on the recording medium.

The fourteenth invention (corresponding to claim 14) provides:
In the playback device according to the first aspect of the present invention, the input section in which the degree of fast-forward and / or fast-rewind can be set by a user, and the degree of fast-forward and / or fast-rewind input to the input section. And causing the computer to function as all or part of the control unit that controls the fast forward playback and / or the fast rewind playback.

According to a fifteenth aspect of the present invention (corresponding to claim 15),
In the playback device according to the tenth aspect of the present invention, the storage unit stores a predetermined frame of a plurality of image data constituting the moving image data in a storage unit, and displays the stored frames simultaneously and collectively. This is a program for causing a computer to function as a control unit.

[0024]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of a recording / reproducing apparatus showing an example of a hardware configuration for realizing the present invention. In FIG. 1, 1 is a digital broadcast recording / reproducing apparatus, 2 is an antenna, 3 is a tuner section,
4 is a digital modulator, 5 is a transport decoder,
Reference numeral 6 denotes an MPEG decoder, 7 denotes a D / A converter, 8 denotes an output unit, 9 denotes a recording information control unit, 10 denotes a recording medium, 11 denotes a scaler, 12 denotes a RAM, and 13 denotes an input unit.

The operation of the recording / reproducing apparatus configured as described above will be described below.

First, the tuner unit 3 is connected to the antenna 2 and the digital broadcast received by the tuner unit 3 is
The data is digitally demodulated by the digital modulating unit 4 and becomes a data stream of a transport stream, which is input to the transport decoder 5. A plurality of programs (programs) and control information are multiplexed in the data stream of the transport stream. One program is selected by the transport decoder 5. The selected program data is M
MPEG decoding is performed by the PEG decoder 6, and digital video and audio are output. This digital video signal is converted into a television signal by the D / A converter 7 and output from the output unit 8.

When recording, the data stream of the transport stream digitally demodulated by the digital modulator 4 is recorded on the recording medium 10 via the recording information controller 9.

When the recorded video is reproduced, the recorded information is read from the recording medium 10 by the recording information control unit 9, is MPEG-decoded by the MPEG decoder 6 via the transport decoder 5, and is converted into a television signal by the D / A converter 7. The output is corrected by the output unit 8.

(First Embodiment) The processing in the FF (fast forward reproduction) and REW (fast rewind reproduction) of the recording / reproducing apparatus according to the first embodiment of the present invention will be described in detail.

When performing FF or REW, a recording information control unit 9 for controlling video data recorded on the recording medium 10 in FIG. 1, recording of FF and REW processing time set values, and temporary recording of a still image And an input unit 13 for inputting setting values and the like from a user. First, the user sets the time interval of the screen change and the display time of the still image displayed for each screen change from the input unit 13 in advance or at the time of FF and REW. Then, when performing FF or REW, the recording information control unit 9
Controls the video output at the time of FF or REW according to the set value. This operation will be described with reference to the flowchart of FIG.

Step 1: The user inputs FF and REW
When the time setting operation is started, the input unit 13 sets the time interval of the screen change and the display time of the still image displayed for each screen change.

Step 3: The set value is recorded in a predetermined area of the RAM 12. Now, as a setting value 1 of a plurality of setting values that can be set by the user, a time interval of a screen change is set to “60 seconds”, and a display time of a still image displayed for each screen change is set to “3 seconds”. It is assumed that the time interval between screen changes is set to “120 seconds” and the display time of a still image displayed for each screen change is set to “5 seconds” as the setting value 2.

Step 4: The user selects, from the input unit 13, an optimum setting value for performing FF / REW according to the scene from a plurality of setting values, and stores the selected setting value in the RAM 12. Record in a predetermined area. Now, it is assumed that the user has selected the setting value 1.

Step 5: FF or REW by user
Step 6: The recording information control unit 9 displays the time interval “60 seconds” of the screen change of the set value 1 recorded in the FF and REW processing time storage area of the RAM 12 and each screen change. The display time “3 seconds” of the still image is read, and the recording information control unit 9 takes out the still image 60 seconds away from the point where the still image was reproduced from the recording medium 10 and displays it for 3 seconds.
Thereafter, the recording information control unit 9 takes out the still image at a point further 60 seconds away from the recording medium 10 and displays it for 3 seconds.
This process is repeated until a user's instruction is issued to perform FF or REW.

Step 7: When the user instructs the reproduction mode. Step 8: When the user instructs the reproduction mode, the recording information control section 9 stops the FF or REW processing and displays it when instructed. Playback is performed from the video at the point where the still image is included.

(Second Embodiment) The processing in the FF and the REW of the recording / reproducing apparatus according to the second embodiment of the present invention will be described in detail.

When performing FF and REW, a recording information control unit 9 for controlling video data recorded on the recording medium 10 in FIG. 1, a scaler 11 for generating an arbitrary n-divided thumbnail image, FF and REW processing time A RAM 12 for temporarily recording set values and a still image, and an input unit 13 for inputting set values and the like from a user are used. First, the user sets the time interval of the screen change from the input unit 13 in advance or at the time of FF and REW. Then, when performing FF or REW, the recording information control unit 9 controls the video output at the time of FF or REW according to the set value. This operation will be described with reference to the flowchart of FIG.

Step 1: The user inputs FF or REW
When the time setting operation is started, Step 2: the time interval of the screen change is set from the input unit 13.

Step 3: The set value is recorded in a predetermined area of the RAM 12. Now, it is assumed that the user sets the time interval of the screen change to “60 seconds”.

Step 4: User inputs FF or REW
Step 5: The recording information control unit 9 reads out the screen change time interval “60 seconds” recorded in the FF and REW processing time storage area of the RAM 12 and reads 6 seconds from the point of reproduction.
A still image at a point separated by 0 second is taken out from the recording medium 10, the still image is reduced by the scaler 11 to 1 / n, and is temporarily recorded in the RAM 12. Then, the still image reduced to 1 / n recorded in the RAM 12 is displayed. After that, the still image at a point 60 seconds away from the recording medium 10 is taken out from the recording medium 10, the still image is reduced by the scaler 11 to 1 / n, and the still image previously reduced and recorded in the RAM 12 is synthesized. , Again RAM12
To record temporarily. Then, a still image that has been reduced, combined, and recorded in the RAM 12 is displayed. By repeating this process, still images are sequentially inserted into the n-divided screen. When a still image is inserted into all the n-divided screens, the next extracted and reduced still image is the still image recorded first among the n still images synthesized and recorded in the RAM 12. A new overwrite composite recording is made in the recorded area,
The synthesized still image is displayed. By repeating this process, F
Perform F or REW.

Step 6: When the user instructs the playback mode, the process of displaying the n-divided thumbnail is
The user selects one still image from the n still images from the input unit 13.

Step 7: When there is a reproduction instruction from the user, the recording information control unit 9 stops the FF or REW processing and reproduces from the video at the point including the still image selected by the user.

In the above-described second embodiment, an example of the thumbnail image display has been described. However, the thumbnail image display is not limited to the above-described example. For example, a case in which n frames are temporarily recorded in the RAM 12 and the n frames are simultaneously displayed collectively is also an example of the thumbnail image display. At this time, the frame displayed at the same time is I
It is not limited to a picture frame. That is, a method of temporarily recording n frames in the RAM 12 and simultaneously displaying the n frames simultaneously is as follows.
It is not a display method that can only be used for F or REW,
This is a display method that can be used even during normal reproduction.

(Third Embodiment) The processing in the FF and the REW of the recording / reproducing apparatus according to the third embodiment of the present invention will be described in detail.

First, at the time of video recording, the time information at the time of recording the video is linked to the video and recorded on the recording medium 10 in advance. Then, the time information is combined with a still image to be displayed at the time of FF or REW and displayed. This operation will be described with reference to the flowchart of FIG.

Step 1: In the case of recording, Step 2: the user inputs the switching of mode A or B to the input unit 13 in advance. Here, the mode A is a mode in which the time counted by the time counting unit of the recording / reproducing apparatus itself is recorded in association with all or a part of each image data to be recorded.
Means that the program start time is obtained from the EPG, and the time elapsed from the start of the program of each image is calculated using time stamp information, which is specified in the MPEG SI information to be recorded and indicates when decoding and reproduction are to be performed. A mode in which the calculated time is recorded as the recording time in association with all or some of the image data to be recorded.

When recording in mode A, step A: record time information indicating the recording time attached to the user data area existing in GOP units with respect to the video data to be recorded. The time information is time reference information that the recording / reproducing device itself has and uses for reserved recording, etc.,
Obtained when recording.

When recording in mode B, step B: record time information indicating the recording time attached to the user data area existing in GOP units with respect to the video data to be recorded. The time information is obtained by obtaining the program start time from the EPG, calculating the elapsed time from the start of the program by using time stamp information defined in the MPEG SI information and indicating when to decode and reproduce, and using these. To get the recording time.

Step 3: User inputs FF or REW
Step 4: The recording information control unit 9 sets the time interval of the screen change of the set value 1 recorded in the FF and REW processing time storage areas of the RAM 12 described in the first embodiment of the present invention. "60 seconds" and the display time "3 seconds" of the still image displayed for each screen change are read. 6 from the point where it was played
The recording information control unit 9 takes out a still image at a point separated by 0 second from the recording medium 10 and temporarily records it in the RAM 12. Then, the time information of the GOP to which the still image belongs is read out, combined with the still image recorded in the RAM 12, and
Display for seconds. Thereafter, the recording information control unit 9 retrieves the still image at a point 60 seconds away from the recording medium 10, reads out the time information of the still image, synthesizes the time information with the still image, and
Display for seconds. This process is repeated until a user's instruction is issued to perform FF or REW. The screen at this time is illustrated in FIG. When the time interval of the screen change is 60 seconds, the still image changes from FIG. 5A to FIG. 5B.

Step 7: When the user instructs the reproduction mode Step 8: When the user instructs the reproduction, the FF and REW processes are stopped, and the point including the still image displayed at the time of the instruction is included. Playback from the video.

According to the recording / reproducing apparatus of each embodiment described above, the screen change interval in the FF and the REW and the display time thereof can be set to a desired time, the degree of freedom in the FF or the REW can be increased, and Usability for screen search can be improved.

Further, according to the recording / reproducing apparatus of each of the above-described embodiments, in the FF and the REW, not only the recognition of the FF or the REW position in the visual sense of the still image display, but also the
Recognition of the FF or REW position based on the sense of time by displaying the time at which the still image was recorded can be performed so that the playback position can be more easily understood.

The present invention is a program for causing a computer to execute the functions of all or some of the components of the above-described reproducing apparatus of the present invention, and is a program that operates in cooperation with the computer.

Note that a part of the present invention means a part of the plurality of parts or a part of the function of one part. Things.

Further, a computer-readable recording medium on which the program of the present invention is recorded is also included in the present invention.

[0056] One embodiment of the program of the present invention may be a mode in which the program is recorded on a computer-readable recording medium and operates in cooperation with the computer.

One embodiment of the program of the present invention may be a mode in which the program is transmitted through a transmission medium, read by a computer, and operates in cooperation with the computer.

The recording medium includes a ROM and the like, and the transmission medium includes a transmission medium such as the Internet,
Light, radio waves, sound waves, etc. are included.

The computer of the present invention described above
The hardware is not limited to pure hardware such as a CPU, but may include firmware, an OS, and peripheral devices.

As described above, the configuration of the present invention may be realized by software or hardware.

[0061]

As is apparent from the above description, a reproducing apparatus which allows a user to freely set the degree of fast-forward and / or fast-rewind during fast-forward playback and / or fast-rewind playback of moving image data. Can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a structure according to an embodiment of the present invention;

FIG. 2 is a flowchart showing a part of a processing operation according to the first embodiment of the present invention;

FIG. 3 is a flowchart showing a part of a processing operation according to the second embodiment of the present invention;

FIG. 4 is a flowchart showing a part of a processing operation according to a third embodiment of the present invention;

FIG. 5 is a diagram illustrating an example of an image displayed by the recording / reproducing device according to the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording / reproducing apparatus 2 Antenna 3 Tuner part 4 Digital modulation part 5 Transport decoder 6 MPEG decoder 7 D / A converter 8 Output part 9 Recording information control part 10 Recording medium 11 Scaler 12 RAM 13 Input part

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 5/92

Claims (15)

[Claims] An input unit for allowing a user to set the degree of fast-forward and / or fast-rewind in a playback device for fast-forward and / or fast-rewind playback of the movie data on a recording medium on which movie data is recorded. And a control unit for controlling the fast forward playback and / or fast rewind playback based on the degree of fast forward and / or fast rewind input to the input unit. 2. The reproducing apparatus according to claim 1, wherein the control unit performs the control by changing a display time interval of each frame without changing a frame to be displayed. 3. The reproducing apparatus according to claim 1, wherein the control unit performs the control by changing a frame to be displayed and changing a display time interval of each frame. 4. A storage section for storing a plurality of degrees of fast-forward and / or fast-rewind as set values, and a user selects one of the plurality of set values stored in the storage section. The playback device according to claim 1, further comprising: a selection unit configured to perform the control based on the setting value selected by the user. 5. A normal playback unit for normally playing back the moving image data, and a second input unit for allowing a user to input a request for fast forward playback or fast rewind playback of the moving image data, In the case of being reproduced, when the user inputs the request, from the image data of the frame displayed at that time, or from the image data in the frame immediately before or immediately after the image data, the control unit, 2. The playback device according to claim 1, wherein the moving image data is played back in a fast-forward or fast-rewind manner. 6. A normal playback section for normally playing back the moving picture data, and a second input section for allowing a user to input an instruction for playing back the moving picture data normally, wherein the moving picture data is fast forward played or rewinded. When the user inputs the instruction, when being played,
From the image data of the frame displayed at that time,
The playback device according to claim 1, wherein the normal playback unit normally plays back the moving image data. 7. Each frame played back in the fast forward playback or fast rewind playback is a frame displayed on a screen having a plurality of display areas, and the control unit sequentially transfers each frame to another display area. The playback device according to claim 1, wherein the playback device displays the information. 8. When the frame is displayed in all of the plurality of display areas, and when displaying another frame, the control unit determines that each frame is displayed in the frame. The reproducing apparatus according to claim 7, wherein the display area is displayed for a substantially constant time in the display area, and all of the plurality of display areas are used cyclically. 9. A normal playback section for normally playing back the moving image data, and a selection section for allowing a user to select any of frames displayed in the plurality of display areas, wherein a plurality of display areas are provided in the plurality of display areas. When a frame is displayed, when the user makes the selection, from the image data of the selected frame, or from the in-frame image data immediately before or immediately after the image data, the normal reproduction unit 9. The playback device according to claim 7, wherein the playback device normally plays back moving image data. 10. A reproducing apparatus for reproducing said moving image data on a recording medium on which moving image data is recorded, wherein a predetermined frame of a plurality of image data constituting said moving image data is stored in a storage unit. A playback device comprising a control unit for simultaneously displaying the stored frames in a batch. 11. A reproduction device according to claim 1, a moving image recording unit for recording the moving image data on the recording medium, and a whole or a part of each image data constituting the moving image data. A time information recording unit that records the time at the time of recording on the recording medium in association with each of the image data, wherein the control unit records the time at the time of recording the image data to be reproduced,
A recording / reproducing apparatus for displaying together with a frame based on the image data related to the time. 12. A recording medium, comprising: a time counting unit that counts time, wherein the time information recording unit uses the time counted by the time counting unit when each of the image data is recorded as the recording time. The recording / reproducing apparatus according to claim 11, wherein the recording / reproducing is performed on the recording medium. 13. The moving image data is broadcast data, wherein the moving image data includes information on the time of reproduction of all or a part of each image data constituting the moving image data. A receiving unit for receiving data and an electronic program guide related to the moving image data; a time when the moving image data is broadcast in the electronic program guide received by the receiving unit; and reproduction of all or a part of each image data Based on information about the time of the hour,
A time calculating unit that calculates a time when each of the image data is recorded, wherein the time information recording unit records the time at which each of the image data is recorded, calculated by the time calculating unit, on the recording medium. Item 12. The recording / reproducing device according to item 11. 14. The input device according to claim 1, wherein the user can set the degree of fast-forward and / or fast-rewind, and the fast-forward and / or fast-rewind input to the input unit. A program for causing a computer to function as all or part of the control unit that controls the fast-forward playback and / or the fast-rewind playback based on the degree. 15. The reproducing apparatus according to claim 10, wherein a predetermined frame of a plurality of image data constituting the moving image data is stored in a storage unit, and the stored frames are simultaneously collectively collected. A program for causing a computer to function as the control unit to be displayed.