JP2013120234A - Image displaying device, image output device, control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable, in an image displaying device that can transmit by cascade connection, to another image displaying device, a part of image data acquired from a connected image output device, the sequence of connection that would maximize the quantity of image data transferrable from the image output device to be notified.SOLUTION: In an image displaying device that can transmit by cascade connection, to another image displaying device, a part of image data acquired from a connected image output device, each image displaying device holds the value of the widest image-transferrable band. The presence or absence of any other connected image displaying device is detected, and the widest image-transferrable band of any other detected image displaying device is acquired. The value of the widest image-transferrable band held by the image displaying device and the value of the widest image-transferrable band of the other image displaying device are compared. If the value of the widest image-transferrable band of the other image displaying device is found greater than the value of the widest image-transferrable band of the image displaying device, guidance to urge a change in the order of connection is displayed.

Description

  The present invention relates to a video display device, a video output device, a control method, and a program capable of cascading a video output device and a plurality of video display devices.

  Currently, various standards exist as an interface for transmitting a video signal to a video display device such as a display. In recent years, instead of DVI (Digital Visual Interface) used for video transmission from video output devices (such as personal computers), a communication system (hereinafter referred to as “DisplayPort Standard” established by VESA (Video Electronics Standards Association). The DisplayPort system ") has become widespread.

  The DisplayPort standard has been revised to Version 1.2 to transmit higher-resolution video or 3D video, and the video transfer bandwidth has been increased from 10.8 Gbps to 21.6 Gbps. Furthermore, in the DisplayPort system, it has become possible to easily construct a video display system environment in which a plurality of video display devices are cascade-connected (connected in series) using only the DisplayPort cable.

  FIG. 14 shows a video display system in which a video output device 141 such as a PC conforming to the DisplayPort standard and two video display devices 142 and 143 are cascade-connected by using DisplayPort cables 144 and 145. In the system as shown in FIG. 14, a part of the video data output from the video output device 141 is displayed on the display unit of the video display device 142, and the other part of the video data is displayed on the display unit of the video display device 143. It becomes possible to make it.

  Conventionally, as a technique related to a system in which a plurality of digital devices are cascade-connected, there is a technique as disclosed in Patent Document 1. In Patent Document 1, in order to easily manage the setting of individual numbers and the connection order of a plurality of digital devices connected in cascade, individual numbers are assigned according to the distance between the master device and the slave device, and the order is followed. It is described that the connected equipment is connected.

JP 2008-294505 A

  In the case of the system shown in FIG. 14, the video data transmitted from the video output device 141 includes the video data to be displayed on the display unit of the video display device 142 and the display of the video display device 143 in the video display device 142. Divided into video data to be displayed on the screen. Then, video data to be displayed on the display unit of the video display device 143 is transmitted from the video display device 142. That is, since the amount of data transmitted through the cable 144 includes video data to be displayed on the display unit of the video display device 142 and video data to be displayed on the display unit of the video display device 143, the amount of data transmitted through the cable 144 is transmitted. Larger than the amount of data.

  From the above, the amount of video data (video transfer bandwidth) that can be transferred from the video output device 141 to the video display device 142 needs to be equal to or greater than the video transfer bandwidth that can be transferred from the video display device 142 to the video display device 143. . When the video transfer band from the video output device 141 to the video display device 142 is small, the amount of data that can be transferred from the video output device 141 to the video display device 142 is reduced. This means that, for example, the number of pixels or the transfer rate of video data that can be displayed on the display unit of the video display device 142 or video data that can be displayed on the video display device 143 decreases.

  In the technique of Patent Document 1, no consideration is given to the amount of video data transmitted between cascade-connected devices. Further, since the connection order is determined by the connection distance between the devices, in the system as shown in FIG. 14, depending on the order in which the user connects the devices, the amount of data that can be transferred is small and video data with a low pixel count May only be displayed.

  The present invention relates to a video display device capable of transmitting video data acquired from a connected video output device to another video display device in a cascade connection, and transferable video data from the video output device to the video display device. The purpose is to notify the connection order that maximizes the volume. Another object of the present invention is to provide a video output device capable of transmitting video data to other video display devices in a cascade connection, in a connection order that maximizes the amount of video data that can be transferred from the video output device to the video display device. It is intended to control to notify.

  In order to achieve the above object, a video display device of the present invention is connected to a video output device, and video data acquired from the video output device can be transmitted to other video display devices in a cascade connection. , Holding means for holding the value of the maximum video transfer band of the video display device, acquisition means for acquiring the maximum video transfer band of the other video display device connected thereto, and the video held by the holding means Comparison means for comparing the value of the maximum video transfer bandwidth of the display device with the value of the maximum video transfer bandwidth of the other video display device acquired by the acquisition means, and the other video display device by the comparison means A display control unit that controls to perform a predetermined notification when the value of the maximum video transfer band is larger than the value of the maximum video transfer band of the video display device.

  According to the present invention, video data acquired from a connected video output device can be transferred from the video output device to the video display device in a video display device capable of transmitting the video data to other video display devices in a cascade connection. It is possible to notify the connection order that maximizes the video data amount. In addition, in a video output device capable of transmitting video data to other video display devices in a cascade connection, the connection order that maximizes the amount of video data that can be transferred from the video output device to the video display device is notified. It becomes possible to control.

1 is a conceptual diagram illustrating a configuration of a video display system according to Example 1. FIG. 3 is a block diagram illustrating a configuration example of a video display device 20. FIG. 3 is a block diagram illustrating a configuration example of a connection control unit 22. FIG. It is a conceptual diagram which shows the example of the data structure which transmits a MainLink line, and the VCID table in this data. It is a conceptual diagram which shows the example of the VCID table comprised by a separation part. It is a conceptual diagram which shows the example of the maximum transfer rate of a video display apparatus, the maximum number of lines, and down data port information. 10 is a flowchart for performing processing for detecting whether or not the connection order of a plurality of connected video display devices is appropriate according to the first embodiment. It is a conceptual diagram which shows the example of the GUI image data displayed on a display part. 1 is a conceptual diagram illustrating a configuration of a video display system according to Example 1. FIG. 4 is a diagram illustrating a correspondence relationship between addresses stored in a storage unit in a connection control unit 32 and information. FIG. 4 is a diagram illustrating a correspondence relationship between addresses stored in a storage unit in a connection control unit 22 and information. FIG. 12 is a flowchart for performing processing for detecting whether or not the connection order of a plurality of connected video display devices is appropriate according to the second embodiment. It is a conceptual diagram which shows the example of the GUI image data displayed on a display part. It is a conceptual diagram showing the video display system which connected the two video display apparatuses to the video output device with the cable.

Example 1
Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration of a video display system according to Embodiment 1 of the present invention. The video output device 10, the video display device 20, and the video display device 30 of the present embodiment are devices compliant with the DisplayPort standard. The video output device 10, the video display device 20, and the video display device 30 can be cascaded using cables 51 and 52.

  The video output device 10 includes a transmitter 11, an output terminal 12, a CPU 13, and a memory 14. The transmitter 11 communicates with a device connected to the output terminal 12 via the output terminal 12. The CPU 13 performs a process of reading and executing a program stored in the memory 14.

  Although the details of the configuration of the video display device 20 will be described later, only the input terminal 21, the connection control unit 22, the receiver 23, and the output terminal 24 are shown in FIG. The video display device 30 has the same configuration as the video display device 20, and only the input terminal 31, connection control unit 32, receiver 33, and output terminal 34 are shown in FIG. 1.

  Each of the cables 51 and 52 has a main link (MainLink) line, an HPD (Hot Plug Detect) line, and an AUX (Auxiliary) channel line. In FIG. 1, the MainLink line, the HPD line, and the AUX channel line are indicated by a dotted line, a broken line, and a solid line, respectively. The MainLink line is a one-way communication line for transferring audio / video data, and the HPD line transmits a signal indicating whether or not the connection control unit (Branch) in the cascaded video display device is operable. Line.

  The AUX channel line is a communication line capable of bidirectionally transmitting device information and authentication information between connected devices. The topology information indicating how the cascade-connected devices are connected is that the transmitter 11 of the video output device 10 and the connection control units 22 and 32 of the video display devices 20 and 30 communicate via the AUX channel line. Managed by.

  In the configuration of FIG. 1, video data transmitted from the video output device 10 to the video display device 20 is output from the Port 0 of the transmitter 11 and input to the input terminal 21 of the video display device 20 through the MainLink line of the cable 51. The Then, the video data is input to Port 0 of the connection control unit 22 and output from Port 1 of the connection control unit 22. Furthermore, the video data is input to Port 0 of the receiver 23 via the MainLink line. The connection through which the video data is transmitted in this way is represented by [0.1] as topology information using the port number from which the video data is output from the transmitter 11 and the connection control unit 22.

  The video data transmitted from the video output device 10 to the video display device 30 is output from the Port 0 of the transmitter of the video output device 10 and then from the Port 2 of the connection control unit 22 via the input terminal 21 of the video display device 20. Is output. Further, the video data is output from the Port 1 of the connection control unit 32 of the video display device 30 via the output terminal 24 and the input terminal 31 and input to the Port 0 of the receiver 33. Therefore, this connection is represented as [0.2.1] as topology information. By sharing these topology information among the cascade-connected devices, the connection control unit in each device can distribute the transmitted video data so that it can be displayed on a predetermined video display device.

  Next, the configuration of the video display device 20 will be described. FIG. 2 is a block diagram illustrating a configuration example of the video display device 20. The video display device 30 has the same configuration. 2, the video display device 20 includes an input terminal 21, a connection control unit 22, a receiver 23, an output terminal 24, a GUI (Graphical User Interface) generation unit 25, an image processing unit 26, a display control unit 27, and a display unit 28. Have. The input terminal 21 can be connected to an output terminal of a video output device such as a PC or a cascade-connectable video display device by using a DisplayPort cable. In the system of the present embodiment, the video output device 10 is connected via the cable 51. The output terminal 24 is connected to the input terminal 31 of the video display device 30 that can be cascade-connected by a cable 52.

  The configuration of the connection control unit 22 will be described in detail with reference to FIG. In FIG. 3, the connection control unit 22 includes a MainLink reception unit 201, a separation unit 202, a MainLink transmission unit 203, a MainLink transmission unit 204, an AUX slave communication unit 205, and an AUX master communication unit 206. Furthermore, it has the comparison part 207, the memory | storage part 208, the HPD detection part 209, and the HPD transmission part 210.

  The MainLink reception unit 201 receives video data input from the input terminal 21 via the MainLink line, confirms that the data code is normal, and transmits the video data to the separation unit 202. The separation unit 202 separates the transmitted video data so as to be distributed to a predetermined MainLin transmission unit.

  A method for separating video data in the separation unit 202 will be described. In this embodiment, the video output device 10 uses the topology information described above to transmit VCID (Virtual ID) to video data (topology information is [0.1]) transmitted from the video output device 10 to the video display device 20. ) Is assigned to 1. Further, it is assumed that VCID is assigned to 2 for video data transmitted from the video output device 10 to the video display device 20 (topology information is [0.2. 1]).

  In the MainLink line of the DisplayPort cable that transmits video data, it is possible to perform time-division transmission with a maximum of 63 divisions according to the number of pixels of the video to be transmitted (required transfer bandwidth). This division unit is defined as a Time slot. FIG. 4A shows an example of a data structure for transmitting the MainLink line of the cable 51, and FIG. 4B shows a VCID table showing the relationship between the Time slot and the VCID in the data structure of FIG. 4A.

  In the data structure of FIG. 4A, video data of VCID = 1 (that is, transmitted to the video display device 20 and displayed on the video display device 20) is stored in the Time slots 1 to 3. Further, it is indicated that video data of VCID = 2 (that is, transmitted to the video display device 30 and displayed on the video display device 30) is stored in the Time slots 4 to 5. The transmitter 11 of the video output device 10 transmits a DPCD (DisplayPor Configuration Data) control request to the AUX slave communication unit 205 through the AUX channel line of the cable 51 together with the VCID table shown in FIG. The DPCD control request is a control request that instructs to write the VCID table into the memory (DPCD storage area). The AUX slave communication unit 205 receives the DPCD control request together with the VCID table from the input terminal 21, and writes the VCID table in the memory (DPCD storage area) in the separation unit 202 according to the DPCD control request. The DPCD address in FIG. 4B indicates an address in the DPCD storage area in which the relationship between each Time slot and VCID is written. The VCID “0” means that there is no video data in the corresponding Time slot.

  From the VCID table stored in the memory, the separation unit 202 in the connection control unit 22 determines that Time Slots 1 to 3 in the video data transmitted through the MainLink line of the cable 51 have VCID = 1. Then, the separation unit 202 creates a VCID table in which the VCID table of FIG. 4B stored in the DPCD storage area of the memory is updated as shown in FIG. The VCID table in FIG. 5A is transmitted from the AUX master communication unit 206 to the receiver 23 together with the DPCD control request, and stored in the DPCD storage area of the memory in the receiver 23. Also, the separation unit 202 separates the video data of the Time slots 1 to 3 with VCID = 1 from the data shown in FIGS. 4A and 4B from the video data received from the MainLink reception unit 201, and transmits the MainLink. To the unit 203. That is, the separation unit 202 separates the video data displayed on the video display device 20 and the video data other than the video data displayed on the video display device 20. The MainLink transmission unit 203 transmits the video data (video data displayed on the video display device 20) transmitted from the separation unit 202 to the receiver 23.

  Similarly to the above, the separation unit 202 determines from the VCID table stored in the memory that the Time slots 4 to 5 of the video data transmitted through the MainLink line of the cable 51 have VCID = 2. Further, the separation unit 202 reconfigures the video data to be transmitted to the video display device 30 so as to be stored in the Time slots 1 and 2 as shown in the VCID table of FIG. The reconstructed video data is transmitted to the MainLink transmission unit 204, and the MainLink transmission unit 204 transmits the video data to the video display device 30 via the output terminal 24. The VCID table in FIG. 5B is transmitted from the AUX master communication unit 206 to the video display device 30 via the output terminal 24 together with the DPCD control request.

  As described above, the separation unit 202 can distribute the video data transmitted from the cable 51. In this embodiment, the connection control unit 22 of the video display device 20 separates the video data displayed on the display unit of the video display device 20 and the video data displayed on the display unit of the video display device 30. Therefore, although the video display device 20 will be described with a configuration in which only video data to be displayed on the display unit of the video display device 30 is transmitted to the video display device 30, the present invention is not particularly limited thereto.

  The video data received by the video display device 20 from the video output device 10 and the video data transmitted to the video display device 30 may be the same video data shown in FIG. That is, the separation unit 202 of the video display device 20 may transmit the video data received from the MainLink reception unit 201 as it is to the MainLink transmission unit 204 without separating the video data. In this case, the video display device 20 displays the video data of the Time slots 1 to 3 with VCID = 1 among the video data received from the video output device 10. The video display device 30 displays the video data of the Time slots 4 and 5 with VCID = 2 among the video data received from the video display device 20.

  The comparison unit 207 in FIG. 3 uses the AUX master communication unit 206 and the output terminal 24 to transmit a video transfer band that can be transmitted on the MainLink line of the video display device 30 connected to the output terminal 24 using the AUX channel line. Get the maximum value (maximum video transfer bandwidth). Further, the comparison unit 207 acquires the maximum video transfer band that can be transmitted through the MainLink line of the video display device 20 and is stored in the storage unit 208 and compares it with the maximum video transfer band of the video display device 30. The comparison unit 207 transmits the comparison result to the GUI generation unit 25.

  FIG. 6A shows the set value of the maximum transfer rate, and FIG. 6B shows the set value of the maximum number of lines. The maximum transfer rate is the maximum amount of transfer data per MainLink line, and the maximum number of lines is the number of MainLink lines that the DisplayPort terminal of the video display device has. The set value of the maximum transfer rate and the set value of the maximum number of lines are stored in a storage unit (DPCD storage area) in the connection control unit included in each of the video display devices 20 and 30.

  6A shows that the set value of the maximum transfer rate is stored in the DPCD address 001 of the DPCD storage area, and FIG. 6B shows that the set value of the maximum number of lines is stored in the address 002. Indicates that The maximum video transfer bandwidth of the video display device 30 connected to the output terminal 24 is the set value of the maximum transfer rate of the video display device 30 read by the AUX master communication unit 206 from the connection control unit in the video display device 30. And the setting value of the maximum number of lines.

  The HPD detection unit 209 illustrated in FIG. 3 detects the operation state of the video display device 30 connected to the receiver 23 and the output terminal 24 through the HPD line. The HPD transmission unit 210 transmits whether or not the AUX slave communication unit 205 is operable to the video output device 10 connected to the input terminal 21 through the HPD line.

  The receiver 23 receives video data from the MainLink transmission unit 203. Further, the receiver 23 transmits to the HPD detection unit 209 whether or not the receiver 23 is operable using the HPD line. The receiver 23 also receives the VCID table and the DPCD control request from the AUX master communication unit 206, and stores the VCID table in the memory in the receiver 23 according to the DPCD control request.

  When it is necessary to change the cascade connection order based on the information from the comparison unit 207, the GUI generation unit 25 generates GUI image data for guidance presentation and transmits the GUI image data to the image processing unit 26. The image processing unit 26 performs predetermined image processing on the video data received from the receiver 23 and the GUI image data received from the GUI generation unit 25 and transmits the processed image data to the display control unit 27. The display control unit 27 controls to display the video data or GUI image data processed by the image processing unit 26 on the display unit 28, and the display unit 28 displays the video data or GUI image data. The output terminal 24 transmits the video data transmitted from the MainLink transmission unit 204 and the VCID table and DPCD control request transmitted from the AUX master communication unit 206 to the connected video display device 30.

  Video data, a VCID table, and a DPCD control request transmitted to the video display device 30 are processed in the video display device 30 having the same configuration as the video display device 20. As shown in FIG. 5B, the video data transmitted to the video display device 30 is composed only of video data with VCID = 2, so that the connection control unit in the video display device 30 has received the video data. Control is performed so that all video data is displayed on the display unit of the video display device 30.

  FIG. 7 is a flowchart for detecting whether or not the connection order of a plurality of video display devices connected in cascade is appropriate and displaying guidance on the display unit of the video display device when the connection order is not appropriate. It is a flowchart of. This flow is performed when the video display devices 20 and 30 are turned on by the user. However, the flow is performed periodically or according to insertion / extraction of a cable connecting a plurality of devices. May be. The flow of FIG. 7 shows the CPU 13 in the video output device 10, the connection control unit 22 in the video display device 20, or the video display device 30 in a state where a plurality of digital devices are cascade-connected as shown in FIG. You may perform each with the connection control part 32. FIG. The description of the flow of FIG. 7 will be given by taking the processing in the video display device 20 as an example.

  In step S701, the HPD detection unit 209 detects whether the HPD signal level from the output terminal 24 is High. If the HPD signal level is Low, it is determined that no device is connected to the output terminal 24, and the process of Step S701 is repeated. If the HPD signal level is High, it is determined that a device is connected to the output terminal 24, and the process proceeds to Step S702. In the configuration of FIG. 1, since the video display device 30 is connected to the output terminal 24, the HPD signal level is detected as High, and the process proceeds to Step S702.

  In step S702, the AUX master communication unit 206 detects whether the video display device 30 connected to the output terminal 24 is a device having a connection control unit through the AUX channel line. Specifically, the AUX master communication unit 206 acquires the down data port information shown in FIG. 6C from the video display device 30. When the video display device 30 has a connection control unit, the down data port information is stored in a memory in the connection control unit. If there is a down data port in the device connected to the output terminal 24 based on the acquired down data port information, it is determined that the device has a connection control unit, and the process proceeds to step S703. If no downdata port exists, it is determined that the device is a receiver device (for example, a reception-only video display device that does not have an output port), and the processing is terminated because the order of cascade connection cannot be changed. . In the configuration of FIG. 1, the video display device 30 includes the connection control unit 32 similarly to the video display device 20, and thus the process proceeds to step S <b> 703.

  In step S703, the AUX master communication unit 206 displays the set value of the maximum transfer rate shown in FIG. 6A and the set value of the maximum number of lines shown in FIG. Read from the memory in the connection control unit 32 of the device 30. In step S704, the comparison unit 207 calculates the maximum video transfer band by multiplying the setting value of the maximum transfer rate and the setting value of the maximum number of lines read in step S703. In step S <b> 705, the comparison unit 207 reads the maximum video transfer band of the video display device 20 from the storage unit 208. In step S706, the comparison unit 207 compares the maximum video transfer bandwidth of the video display device 20 with the maximum video transfer bandwidth of the device (video display device 30) connected to the output terminal 24 calculated in step S704. .

  If the maximum video transfer bandwidth of the video display device 20 is larger than the maximum video transfer bandwidth of the connection device (video display device 30) of the output terminal 24, there is no particular problem with the connection order of the cascade connection, so the processing ends. . When the maximum video transfer bandwidth of the video display device 20 is smaller than the maximum video transfer bandwidth of the connection device of the output terminal 24, the video transfer capability of a plurality of cascade-connected video display devices is used to the maximum. There is no possibility. If the maximum video transfer bandwidth of the video display device 20 is smaller than the maximum video transfer bandwidth of the connected device of the output terminal 24, in step S707, the GUI generation unit 25 prompts the user to change the connection order of the video display devices. GUI image data is generated. For example, GUI image data as shown in FIG. 8 is generated by the GUI generation unit 25, and the display control unit 27 controls the display unit 28 to display the GUI image data.

  In step S702 in FIG. 7, the video display device 30 determines whether the AUX master communication unit in the connection control unit 32 is a device having a connection control unit in the video display device connected to the output terminal 34. Detect through. In the configuration of FIG. 1, since no video display device is connected to the output terminal 34 of the video display device 30, the AUX master communication unit in the connection control unit 32 determines No in step S702 and ends the process.

  In the video output device 10, the video display device 20 having a connection control unit is connected to the output terminal 12 (Yes in step S702). In step S <b> 703, the CPU 13 reads the set value for the maximum transfer rate and the set value for the maximum number of lines from the video display device 20 connected to the output terminal 12. The video display device 20 at this time also stores a setting value for the maximum transfer rate and a setting value for the maximum number of lines of the video display device 30 connected to the output terminal 24 of the video display device 20. Therefore, in step S703, the video output device 10 reads the setting value of the maximum transfer rate and the setting value of the maximum number of lines of the video display device 20 and the video display device 30, respectively. From these setting values, the CPU 13 determines in step S706 whether or not the video display device 20 connected to the output terminal 12 of the video output device 10 has a narrower maximum video transfer bandwidth than the video display device 30. To do. When it is better to change the connection order, the CPU 13 in the video output device 10 generates GUI image data that prompts the user to change the connection order of the video display device, and the video display device 20 and the video display device. One of 30 is instructed (step S707).

  As described above, according to the first embodiment, in the video display device capable of transmitting a part of the video data acquired from the video output device to another video display device, the maximum video transfer bands of the plurality of video display devices are compared. Thus, it is possible to present a more appropriate connection order of the video display devices. In addition, in a video output device capable of transmitting video data to other video display devices in a cascade connection, the connection order that maximizes the amount of video data that can be transferred from the video output device to the video display device is notified. It becomes possible to control. Furthermore, by changing the cascade connection order, the number of pixels of video data that can be transmitted from the video output device to the video display device is improved, and high-definition display can be performed.

(Example 2)
Next, Example 2 will be described. In the first embodiment, the case where two video display devices are cascade-connected to the video output device 10 is described. In the second embodiment, a case where three or more video display devices are connected will be described. . FIG. 9 is a conceptual diagram illustrating an example of a video display system in which the video output device 10 according to the second embodiment and three video display devices 20, 30, and 40 are connected by cables 51, 52, and 53. In the video display system of FIG. 1 according to the first embodiment, the video display device 40 is connected to the output terminal 34 of the video display device 30. Components having the same functions as those of the devices and blocks in FIGS. 1 and 2 are given the same reference numerals. Example 2 will be described using the video display system shown in FIG.

  Similar to the video display devices 20 and 30, the video display device 40 is a device compliant with the DisplayPort standard, and includes an input terminal, a connection control unit, a receiver unit, an output terminal, a GUI generation unit, an image processing unit, a display control unit, a display Part. The video display devices 20, 30, and 40 shown in FIG. 9 have an input terminal (21, 31, 41), a connection control unit (22, 32, 42), and an output terminal (24, 34) for the sake of simplicity. 44) and only the display sections (28, 38, 48).

  Thick arrows in FIG. 9 conceptually show the flow of video data. The video data output from the video output device 10 includes video data displayed on the video display device 20, the video display device 30, and the video display device 40, respectively. As shown in FIG. 9, in the video display device 20, video data input from the video output device 10 via the cable 51 should be displayed on the display unit 28 of the video display device 20 (assigned to the video display device 20. The connection control unit 22 separates the video data. The remaining video data is transmitted to the video display device 30 via the cable 52. In the video display device 30, the video data to be displayed on the display unit 38 of the video display device 30 among the video data output from the video display device 20 is separated by the connection control unit 32, and the remaining video data is transmitted via the cable 53. To the video display device 40. The video display device 40 displays the video data transmitted from the video display device 30 on the display unit 48.

  In Example 1, in the video system shown in FIG. 1, the video display device 20 acquires and compares the value of the maximum video transfer bandwidth of the video display device 20 and the value of the maximum video transfer bandwidth of the video display device 30, Judged whether the connection order is appropriate. On the other hand, the video display device 20 of the present embodiment acquires and compares the maximum video transfer band value of the video display device 40 in addition to the video display devices 20 and 30 in the video display system shown in FIG. Determine whether the connection order is appropriate.

  The value of the maximum video transfer bandwidth of each video display device is stored in a storage unit in each video display device. In the video system shown in FIG. 9, each video display device acquires the value of the maximum video transfer band held in the video display device connected to the output terminal of each video display device. A method for acquiring the value of the maximum video transfer band by each video display device will be described.

  In the system of FIG. 9, the output terminal 44 of the video display device 40 is not connected to any video display device. Accordingly, only the setting value of the maximum transfer rate and the setting value of the maximum line of the video display device 40 are stored in the storage unit in the connection control unit 42 of the video display device 40. As described above, when there is no device connected to the output terminal, the number of cascade stages indicating the number of cascade connected to the video display device 40 is zero. The number of cascade stages is also stored in the storage unit in the connection control unit 42.

  Next, the output terminal 34 of the video display device 30 is connected to the video display device 40. The connection control unit 32 of the video display device 30 reads the value of the maximum video transfer band and the number of cascade stages held by the video display device 40. Specifically, the AUX master communication unit in the connection control unit 32 uses the AUX channel line to set the maximum transfer rate setting value and the maximum number of lines from the storage unit in the connection control unit 42 of the video display device 40. Read the value and the number of cascade stages.

  The number of cascade stages of the video display device 30 in which the video display device 40 having 0 cascade stages is connected to the output terminal is one. The video display device 30 uses the acquired setting values for the maximum transfer rate and the maximum number of lines of the video display device 40 and the number of cascade stages of the video display device 30 (own device) as the maximum transfer rate and the maximum number of lines of the video display device 30. Are stored in the storage unit of the connection control unit 32. FIG. 10 shows the correspondence between the address stored in the storage unit in the connection control unit 32 of the video display device 30 and each piece of information. The address 510 stores the number of cascade stages = 1 of the video display device 30. Addresses 511 and 512 respectively store a setting value for the maximum transfer rate and a setting value for the maximum number of lines of the video display device 40 with the number of cascade stages = 0.

  Next, the output terminal 24 of the video display device 20 is connected to the video display device 30. The connection control unit 22 of the video display device 20 reads the value of the maximum video transfer band and the number of cascade stages held in the storage unit in the connection control unit 32 of the video display device 30. In the storage unit in the connection control unit 32, the setting value of the maximum transfer rate and the setting value of the maximum number of lines of the video display device 40, the setting value of the maximum transfer rate and the setting value of the maximum number of lines of the video display device 30, and video The number of cascade stages (one stage) of the display device 30 is stored, and these are read out.

  The number of cascade stages of the video display device 20 in which the video display device 30 having one cascade stage is connected to the output terminal is two. The video display device 20 sets the acquired maximum transfer rate and the maximum number of lines of the video display devices 30 and 40, the cascade stage number of the video display device 20, and the maximum transfer rate and the maximum number of lines of the video display device 20. It is stored in the storage unit of the connection control unit 22 together with the set value.

  As described above, the maximum transfer rate setting value and the maximum line number setting value of the video display device 30 and the video display device 40 are stored in the storage unit in the connection control unit 22 of the video display device 20. . FIG. 11 is a diagram illustrating a correspondence relationship between addresses stored in the storage unit in the connection control unit 22 and each piece of information. The address 510 stores the number of cascade stages = 2 of the video display device 20. Addresses 511 and 512 respectively store a setting value for the maximum transfer rate and a setting value for the maximum number of lines of the video display device 40 with the number of cascade stages = 0. In addition, at address 513 and address 514, the setting value of the maximum transfer rate and the setting value of the maximum number of lines of the video display device 30 of the number of cascade stages = 1 stage are stored.

  FIG. 12 is a flowchart for performing processing for detecting whether or not the connection order of a plurality of connected video display devices is appropriate in the second embodiment. The flowchart shown in FIG. 12 is performed by each of a plurality of video display devices that constitute the video display system. The configuration of the connection control unit in each video display device is the same as that in FIG. 3, and the description of FIG. The connection control unit 22 of the video display device 20 has the configuration shown in FIG. 3 and will be described with reference to the block diagram of FIG.

  First, in step S1201, the AUX master communication unit 206 reads the cascade stage number stored in the storage unit in the connection control unit of the device connected to the output terminal 24. As described above, the number of cascade stages of the video display device 30 stored in the storage unit in the connection control unit of the video display device 30 connected to the video display device 20 is two. Next, in step S1202, the storage unit 208 adds one to the cascade stage number read in step S1201 as the cascade stage number of its own device (video display device 20) in the DPCD storage area in the storage unit 208. Store.

  In step S1203, the AUX master communication unit 206 reads the setting value for the maximum transfer rate and the setting value for the maximum number of lines stored in the storage unit in the connection control unit of the device connected to the output terminal 24. In step S1204, the storage unit 208 stores the setting value of the maximum transfer rate and the setting value of the maximum number of lines read in step S1203 in the DPCD storage area in the storage unit 208.

  In step S <b> 1205, the AUX slave communication unit 205 detects whether or not there is a read request for the number of cascade stages from the input terminal 21 of the video display device 20. If there is a read request for the number of cascade stages, it is determined that there is another device on the video output device side (upstream side) relative to the device of the device itself, and the process is terminated.

  If there is no request for reading the number of cascade stages, it is determined that the device (video display device 20) performing the processing of the flow in FIG. 12 is most connected to the video output device side (upstream side). Move on to processing.

  At this time, the storage unit in the connection control unit of the video display device 20 stores the setting value of the maximum transfer rate and the setting value of the maximum number of lines of a plurality of video display devices cascaded in the video display system. . Accordingly, in step S1206, the comparison unit 207 determines the device (video display device 20) of the own apparatus that is performing the processing of the flow of FIG. 12, the value of the maximum video transfer bandwidth, and the maximum of other devices (video display devices). Compare with the value of video transfer bandwidth. As in the first embodiment, the maximum video transfer bandwidth value is calculated by multiplying the maximum transfer rate setting value by the maximum line number setting value. The comparison unit 207 sets an order of descending values of the maximum video transfer bandwidth as an appropriate connection order.

  In step S1207, the AUX master communication unit receives the comparison result of the comparison unit 207 in step S1206, and notifies each video display device of the connection order through the AUX channel line. For example, when the value of the maximum video transfer bandwidth is large in the order of video display device 40> video display device 20> video display device 30, the video display device 40 has the first connection order, the video display device 20 has the second connection order, and the video. The display device 30 is notified of the connection order No. 3.

  In step S1208, the GUI generation unit of each video display device generates GUI image data for notifying the connection order according to the received connection order. Then, the generated GUI image data is displayed on the display unit of each video display device as shown in FIG. 13 by the display control unit.

  In the present embodiment, the case where the values of the maximum video transfer bands of the three video display devices are different is described, but the same may be used. For example, if the value of the maximum video transfer band is video display device 40> video display device 20 = video display device 30, video display device 40 and video display device need only be first in the connection order. The connection order of 30 is not particularly limited. Moreover, although it demonstrated by the structure which displays the GUI image which notifies a connection order on the display part of each video display apparatus like FIG. 13, it is not restricted to this. For example, a diagram of a video display system as shown in FIG. 13 may be displayed on the display unit of one video display device among a plurality of video display devices to notify an appropriate connection order.

  As described above, according to the present embodiment, the video data acquired from the video output device can be transmitted to another video display device, or the video output device includes three or more video display devices. Even in this case, the maximum video transfer bandwidth of each video display device is compared. By comparing the maximum video transfer bandwidths of the video display devices, it is possible to present a more appropriate connection order of the video display devices to the display unit of the video display device. Furthermore, by changing the cascade connection order, the number of pixels of video data that can be transmitted to each video display device is improved, and high-definition display can be performed.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that implements the functions of the above-described embodiments is supplied to the system or apparatus via a network or various storage media (memory such as ROM or RAM). The system or apparatus computer (or a control unit such as a CPU or MPU) reads out and executes the program. Therefore, the computer program itself for realizing the functions of the above-described embodiments is also one aspect of the present invention.

DESCRIPTION OF SYMBOLS 10 Image | video output apparatus 20 Image | video display apparatus 22 Connection control part 23 Receiver 25 GUI production | generation part 202 Separation part 207 Comparison part 208 Storage part

Claims (9)

In a video display device connected to a video output device and capable of transmitting video data acquired from the video output device to another video display device in a cascade connection,
Holding means for holding a value of a maximum video transfer bandwidth of the video display device;
Obtaining means for obtaining the maximum video transfer bandwidth of the other video display device connected;
Comparison means for comparing the value of the maximum video transfer bandwidth of the video display device held by the holding means with the value of the maximum video transfer bandwidth of the other video display device acquired by the acquisition means;
A display control unit that controls to perform a predetermined notification when the value of the maximum video transfer bandwidth of the other video display device is larger than the value of the maximum video transfer bandwidth of the video display device by the comparison means And a video display device. Having detecting means for detecting whether or not another video display device is connected;
The video display device according to claim 1, wherein the acquisition unit acquires a maximum video transfer band of the other video display device detected by the detection unit. Separating means for separating video data displayed on the video display device from video data acquired from the video output device and video data other than video data displayed on the video display device;
3. The output device according to claim 1, further comprising an output unit configured to output video data separated by the separation unit and other than video data to be displayed on the video display device to the other video display device. Video display device.   The display control unit, when the value of the maximum video transfer bandwidth of the other video display device is larger than the value of the maximum video transfer bandwidth of the video display device by the comparing means, 4. The video display device according to claim 1, wherein guidance is displayed so as to be connected to the video output device. 5.   When there are a plurality of the other video display devices, GUI image data for notifying the connection order to the video output device in order of increasing value of the maximum video transfer bandwidth based on the comparison result by the comparison means. 5. The video display device according to claim 1, wherein the display control unit controls the display unit to display the image on a display unit of each video display device. 6. In a video output device capable of transmitting video data in a cascade connection to a first video display device connected to the video output device and a second video display device connected to the first video display device,
Obtaining means for obtaining maximum video transfer bandwidths of the first video display device and the second video display device;
Comparison means for comparing the value of the maximum video transfer bandwidth of the first video display device and the value of the maximum video transfer bandwidth of the second video display device acquired by the acquisition means;
When the maximum video transfer bandwidth value of the second video display device is greater than the maximum video transfer bandwidth value of the first video display device by the comparing means, the first video display device and A video output device comprising: a control unit configured to control one of the second video display devices to perform a predetermined notification. In a control method of a video display device connected to a video output device and capable of transmitting video data acquired from the video output device to another video display device in a cascade connection,
An obtaining step of obtaining a maximum video transfer bandwidth of the other video display device;
A comparison step of comparing the value of the maximum video transfer bandwidth of the video display device held in a storage unit with the value of the maximum video transfer bandwidth of the other video display device acquired in the acquisition step;
Display control step of controlling to perform a predetermined notification when the value of the maximum video transfer band of the other video display device is larger than the value of the maximum video transfer bandwidth of the video display device by the comparison step And a method for controlling the video display device. Control of video output device capable of transmitting video data in cascade connection to first video display device connected to video output device and second video display device connected to first video display device In the method
An obtaining step of obtaining maximum video transfer bandwidths of the first video display device and the second video display device;
A comparison step of comparing the value of the maximum video transfer bandwidth of the first video display device and the value of the maximum video transfer bandwidth of the second video display device acquired in the acquisition step;
When the value of the maximum video transfer band of the second video display device is larger than the value of the maximum video transfer bandwidth of the first video display device, the first video display device and the second video And a control step of performing control so that a predetermined notification is given to any one of the display devices.   The program for making a computer perform each step of the control method of the video output device of Claim 7 or 8.

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