Display Control Device

Abstract

To provide a display controller and a display control method capable of displaying a desired image, regardless of a state of wireless communication.SOLUTION: A wireless control unit 31 transmits input information IN to an external device through wireless communication draws, thereby, causing the external device to draw an image IMGA according to the input information IN. A unit UA acquires the image IMGA drawn by the external device, through the wireless communication, and causes a display device 16 to display the image IMGA. A unit UB includes a GPU 35, causes the GPU 35 to draw an image IMGB according to the input information IN, and causes the display device 16 to display the image IMGB drawn by the GPU 35. A switching unit 32 determines whether a received radio wave is in an excellent state or a defective state, selects the unit UA when a determined result is the excellent state, and selects the unit UB when the determined result is the defective state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a display control device and a display control method. [Background technology]

[0002] Patent Document 1 shows an information providing / distributing server that can provide service information associated with a narrower location to a requesting terminal. Specifically, the information providing / distributing server extracts mobile terminals in a first area based on base station information of a plurality of mobile terminals, and determines mobile terminals in a second area narrower than the first area as target terminals based on GPS information of the extracted mobile terminals. The information providing / distributing server transmits the provided information from the target terminals to the requesting terminal.

[0003] Patent Document 2 shows a mobile communication system capable of displaying information related to a location with little delay. Specifically, the mobile communication system includes a mobile communication terminal and a content distribution server. The content distribution server stores a plurality of pieces of content information related to a plurality of communication areas. In response to switching of the communication area, the mobile communication terminal acquires content information related to the communication area of ​​the switching destination from the content distribution server, and displays content information based on the location of the mobile communication terminal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-16988 A [Patent Document 2] JP 2006-217105 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, connected cars that can obtain various information from a server device on a network via wireless communication are becoming more common. In particular, display control devices mounted on such vehicles are required to execute more complex graphics rendering processes. However, as the graphics rendering process becomes more complex, power consumption may increase. Increased power consumption is particularly undesirable in vehicles such as electric vehicles.

[0006] On the other hand, it is expected that the communication speed of wireless communication will increase step by step. Therefore, a system in which the graphics rendering process is performed by a server device instead of a display control device can be considered. However, wireless communication is not always stable.

[0007] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0008] A display control device according to an embodiment performs wireless communication with an external device and displays an image corresponding to input information on a display device, and includes a wireless control unit, first and second units, and a switching unit. The wireless control unit transmits input information to the external device via wireless communication, causing the external device to draw a first image corresponding to the input information. The first unit acquires the first image drawn by the external device via wireless communication, and causes the display device to display the first image. The second unit includes a GPU, causes the GPU to draw a second image corresponding to the input information, and causes the display device to display the second image drawn by the GPU. The switching unit determines whether the received radio wave is in a good state or a bad state, and selects the first unit if the determination result is in a good state, and selects the second unit if the determination result is in a bad state. Effect of the Invention

[0009] According to the embodiment, it is possible to display a desired image regardless of the state of wireless communication. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a configuration example of a main part of an information processing system according to the first embodiment. [Diagram 2] FIG. 2 is a flow chart showing an example of the processing contents of a software processing unit in the display control device appearing in FIG. [Diagram 3] FIG. 3 is a schematic diagram showing a configuration example of a main part of a terminal device according to the second embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a configuration example of a main part of a terminal device according to the third embodiment. [Figure 5A] FIG. 5A is a timing chart showing an example of an operation that may occur when the example configuration of FIG. 3 is used as a premise for the terminal device of FIG. [Figure 5B] FIG. 5B is a timing chart showing an example of operation when the terminal device of FIG. 4 is used. [Figure 5C] FIG. 5C is a timing chart showing an operation example different from that in FIG. 5B when the terminal device in FIG. 4 is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the following embodiments, when necessary for convenience, the description will be divided into multiple sections or embodiments, but unless otherwise specified, they are not unrelated to each other, and one is a partial or complete modification, detail, supplementary explanation, etc. of the other. Furthermore, in the following embodiments, when the number of elements, etc. (including the number, numerical value, amount, range, etc.) is mentioned, it is not limited to that specific number, and may be more or less than the specific number, unless otherwise specified or clearly limited in principle to a specific number.

[0012] Furthermore, in the following embodiments, the components (including element steps, etc.) are not necessarily essential unless otherwise specified or considered to be obviously essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc. of components, etc., it is intended to include those that are substantially similar or similar to the shape, etc., unless otherwise specified or considered to be obviously not essential in principle. The same applies to the above numerical values ​​and ranges.

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining the embodiment, the same members are generally designated by the same reference numerals, and the repeated description will be omitted.

[0014] (Embodiment 1) <Outline of the information processing system> Fig. 1 is a schematic diagram showing a configuration example of a main part of an information processing system according to embodiment 1. The information processing system shown in Fig. 1 is, for example, a system for a vehicle. The information processing system includes a terminal device 10a, a server device 12, and a wireless network 11 that connects the terminal device 10a and the server device 12. The terminal device 10a is, for example, a mobile communication device mounted on a vehicle.

[0015] The terminal device 10a includes a display control device 15 and a display device 16. The display control device 15 is configured, for example, by a wiring board on which various components are mounted. The display control device 15 performs wireless communication with a server device 12, which is an external device, and has a function of displaying an image corresponding to input information IN on the display device 16. The display device 16 is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or the like.

[0016] The display control device 15 includes a semiconductor device 20, an input interface 21, an external memory 22, a detector 23, and a wireless device 24. The input interface 21 accepts input from a user via a touch panel, an operation button, a microphone for voice input, etc. (not shown). The input interface 21 also accepts input from a sensor (not shown) for acquiring various vehicle information.

[0017] For example, when the input interface 21 receives an input from a user, the input interface 21 generates information on the input content and vehicle information related to the input content as input information IN. Furthermore, when various events occur, the input interface 21 generates related vehicle information as input information IN. The input information IN is information necessary for drawing an image. The external memory 22 is, for example, a DRAM (Dynamic Random Access Memory) or the like. The external memory 22 is a frame memory, and stores frame data FRM representing an image to be displayed by the display device 16.

[0018] The wireless device 24 performs wireless communication with the server device 12 using a transmission radio wave TX or a reception radio wave RX. The wireless device 24 is composed of, for example, an analog front-end IC that performs modulation processing / demodulation processing, a power amplifier used when transmitting the transmission radio wave TX, and the like. The detector 23 detects the state of the reception radio wave RX and outputs the detection result as a detection signal DET. The detector 23 typically detects the intensity of the reception radio wave RX. In this case, a detection circuit for radio wave intensity that is generally installed in many wireless devices 24 may be used as the detector 23. Note that the detector 23 is not limited to the intensity of the reception radio wave RX, and may detect, for example, an error rate at the time of reception obtained from an error detection code or the like.

[0019] The semiconductor device 20 is, for example, a System on Chip (SoC) configured on one semiconductor chip. The semiconductor device 20 includes two units UA and UB, a wireless control unit 31, a switching unit 32, and an internal memory 36. The internal memory 36 is, for example, a DRAM, a Static Random Access Memory (SRAM), or a combination of these.

[0020] The wireless control unit 31 inputs the input information IN from the input interface 21 and transmits the input information IN to the server device 12 via wireless communication, i.e., the wireless device 24, thereby causing the server device 12 to render an image IMGA corresponding to the input information IN. Specifically, the wireless control unit 31 inputs the input information IN, generates transmission data TD including the input information IN, and outputs it to the wireless device 24. The wireless device 24 modulates the transmission data TD from the wireless control unit 31 to transmit the transmission data TD, and thus a transmission radio wave TX including the input information IN, to the server device 12.

[0021] The unit UA has a function of acquiring the image IMGA drawn by the server device 12, more specifically, the encoded image IMGAe, via wireless communication, i.e., the wireless device 24, and displaying the acquired image IMGA on the display device 16. That is, the unit UA stores the image IMGA drawn by the server device 12 in the external memory 22, which is a frame memory, and thereby displays the image IMGA on the display device 16.

[0022] Specifically, the unit UA includes an image reproduction unit 33 and a decoder 37. The image reproduction unit 33 acquires an image IMGAe that has been rendered by the server device 12 and then encoded, via wireless communication, i.e., the wireless device 24. Specifically, the wireless device 24 receives a received radio wave RX including the encoded image IMGAe from the server device 12 in response to transmission of a transmitted radio wave TX. The wireless device 24 demodulates the received radio wave RX to output received data RD. The image reproduction unit 33 inputs the received data RD from the wireless device 24, and acquires the encoded image IMGAe included in the received data RD.

[0023] The decoder 37 decodes the image acquired by the image playback unit 33, i.e., the image IMGAe encoded by the server device 12, based on an instruction from the image playback unit 33 to restore the original image IMGA. Then, the decoder 37 stores the restored image IMGA in the external memory 22. The decoder 37 is typically an MPEG decoder, a JPEG decoder, or the like.

[0024] On the other hand, the unit UB has a function of causing a GPU (Graphics Processing Unit) 35 to draw an image IMGB corresponding to the input information IN, and displaying the image IMGB drawn by the GPU 35 on the display device 16. That is, the unit UB stores the image IMGB drawn by the GPU 35 in the external memory 22, which is a frame memory, and thereby displays the image IMGB on the display device 16. Note that, although the external memory 22 provided outside the semiconductor device 20 is used as the frame memory in this example, an internal memory 36 provided inside the semiconductor device 20 may be used instead.

[0025] More specifically, the unit UB includes a rendering control unit 30 and a GPU 35. The rendering control unit 30 receives input information IN from the input interface 21, and outputs a rendering start command GST based on the input information IN. The GPU 35 renders an image IMGB, i.e., an image IMGB corresponding to the input information IN, in response to the rendering start command GST from the rendering control unit 30. The GPU 35 then stores the rendered image IMGB in the external memory 22. Furthermore, when the GPU 35 finishes rendering the image IMGB, it outputs a rendering end notification GED to the rendering control unit 30.

[0026] The switching unit 32 judges whether the received radio wave is in a good state or a bad state, and selects the unit UA if the judgement result is in a good state, and selects the unit UB if the judgement result is in a bad state. Specifically, the switching unit 32 judges whether the state is in a good state or a bad state based on the detection signal DET from the detector 23. For example, the switching unit 32 judges the state to be in a good state when the strength of the received radio wave RX is higher than a threshold value or the error rate is lower than a threshold value. On the other hand, the switching unit 32 judges the state to be in a bad state when the strength of the received radio wave RX is lower than a threshold value or the error rate is higher than a threshold value.

[0027] The switching unit 32 outputs a signal indicating whether the state is good or bad as a selection signal SL to the two units UA and UB. When the selection signal SL indicates a good state, the unit UA stores the restored image IMGA in the external memory 22, and when the selection signal SL indicates a bad state, the unit UA stops operating. Specifically, when the selection signal SL indicates a bad state, the image reproducing unit 33 stops operating.

[0028] On the other hand, when the selection signal SL indicates a bad state, the unit UB stores the rendered image IMGB in the external memory 22, and when the selection signal SL indicates a good state, the unit UB stops at least the rendering operation by the GPU 35. In the example of Fig. 1, the rendering control unit 30 stops the operation when the selection signal SL indicates a bad state, and as a result, does not output the rendering start command GST to the GPU 35.

[0029] Here, for example, the drawing control unit 30, the wireless control unit 31, the switching unit 32, and the image playback unit 33 constitute a software processing unit 38. The software processing unit 38 is realized by a CPU (Central Processing Unit) executing software stored in the internal memory 36. However, the realization method is not necessarily limited to this. For example, the switching unit 32 may be realized by dedicated hardware. Also, the decoder 37 may be realized by software processing in some cases.

[0030] The server device 12 includes a drawing unit 40, an encoder 41, and a wireless device 42. The wireless device 42 performs wireless communication with the wireless device 24 of the terminal device 10a. For example, the wireless device 42 receives a transmission radio wave TX from the wireless device 24, and outputs demodulated data including input information IN by demodulating the transmission radio wave TX. The drawing unit 40 inputs the demodulated data and acquires the input information IN included in the demodulated data. Then, the drawing unit 40 draws an image IMGA corresponding to the input information IN based on the acquired input information IN. The drawing unit 40 is realized, for example, by software processing using the CPU of the server device 12, or by combining the software processing with hardware processing using a GPU or the like.

[0031] The encoder 41 encodes the image IMGA drawn by the drawing unit 40 and outputs the encoded image IMGAe. The encoder 41 is typically an MPEG encoder or a JPEG encoder. The wireless device 42 modulates the image IMGAe from the encoder 41 to transmit radio waves, i.e., received radio waves RX as seen from the wireless device 24, to the wireless device 24 of the terminal device 10a.

[0032] <Operation of the software processing section> Fig. 2 is a flow diagram showing an example of the processing contents of the software processing unit in the display control device in Fig. 1. In Fig. 2, first, the switching unit 32 judges the state of the received radio wave RX based on the detection signal DET from the detector 23 (step S101). If the judgment result in step S101 is a good state, the switching unit 32 proceeds to step S103 (step S102).

[0033] In step S103, the switching unit 32 uses the selection signal SL to select one unit UA and cancel the selection of the other unit UB. Next, when input information IN is received from the input interface 21, the wireless control unit 31 generates transmission data TD including the input information IN and transmits the transmission data TD to the server device 12 via wireless communication (steps S104 and S105). As a result, the wireless control unit 31 causes the server device 12 to draw an image IMGA corresponding to the input information IN.

[0034] Thereafter, the image reproducing unit 33 in the selected unit UA acquires the image IMGA rendered by the server device 12 via wireless communication, and displays the image IMGA on the display device 16 (step S106). Note that, in step S104, if no input information IN is received from the input interface 21, the software processing unit 38 ends the process and starts the process of step S101 again.

[0035] On the other hand, if the determination result in step S101 is a defective state, the switching unit 32 proceeds to step S107 (step S102). In step S107, the switching unit 32 uses the selection signal SL to cancel the selection of one unit UA and select the other unit UB.

[0036] Next, when input information IN from the input interface 21 occurs, the rendering control unit 30 in the selected unit UB causes the GPU 35 to render an image IMGB corresponding to the input information IN, and causes the image IMGB rendered by the GPU 35 to be displayed on the display device 16 (step S109). Specifically, the rendering control unit 30 outputs a rendering start command GST based on the input information IN to the GPU 35. Note that, in step S108, when input information IN does not occur from the input interface 21, the software processing unit 38 ends the process and starts the process of step S101 again.

[0037] The image IMGA acquired in step S106 and the image IMGB drawn in step S109 may be, for example, an image showing the state of the vehicle, various images according to the contents of the user's input, etc. For example, the drawing control unit 30 inputs information on the contents of the user's input as input information IN, determines the contents of the image IMGB based on the input information IN, and outputs a drawing start command GST to the GPU 35 to draw the determined image IMGB.

[0038] Also, the process of the wireless control unit 31 in step S105 may be executed regardless of the judgment results in steps S101 and S102, depending on the circumstances. That is, the wireless control unit 31 may output the transmission data TD even if the judgment result is a bad state. For example, the wireless device 24 may stop transmitting the transmission radio wave TX when the strength of the reception radio wave RX does not satisfy the condition. In this case, even if the wireless control unit 31 outputs the transmission data TD, the transmission data TD is not transmitted to the server device 12. In this way, when the judgment result is a bad state, the wireless control unit 31 or the wireless device 24 controls so that the transmission radio wave TX is not transmitted, thereby reducing the power consumption of the wireless device 24 and, ultimately, the terminal device 10a.

[0039] Here, particularly in the terminal device 10a mounted on an electric vehicle or the like, reduction in power consumption is required. In this regard, in the display control device 15 of FIG. 1, by using the unit UA, power consumption may be reduced in some cases compared to the case where the unit UB is used. For example, the magnitude of power consumption when the unit UA is used is mainly determined by the transmission operation of the transmission radio wave TX by the wireless device 24. Therefore, when the amount of information of the input information IN is sufficiently small, the power consumption of the wireless device 24 may be sufficiently smaller than the power consumption of the GPU 35.

[0040] For this reason, it is conceivable to mount only the unit UA on the display control device 15. However, in this case, during the period when the state of wireless communication is poor, the desired image cannot be displayed on the display device 16. In particular, in fields where high safety is required, such as automobiles, a mechanism is required that can display the desired image regardless of the state of wireless communication in order to convey appropriate information to the user at the appropriate time. Therefore, it is useful to provide a unit UB and a switching unit 32, etc., and switch between the two units UA and UB according to the state of wireless communication, specifically, the state of the received radio wave RX.

[0041] Furthermore, when the two units UA, UB are switched, it is desirable to display the images IMGA, IMGB from the two units UA, UB on the display device 16 without interruption. To achieve this, the operation of the drawing control unit 30 in the terminal device 10a and the operation of the drawing unit 40 in the server device 12 must be synchronized. In the display control device 15 of FIG. 1, the drawing control unit 30 inputs input information IN, and the wireless control unit 31 also inputs the same input information IN and transmits it to the server device 12, thereby realizing synchronization between the drawing control unit 30 and the drawing unit 40.

[0042] For example, in order to more reliably synchronize the drawing control unit 30 and the drawing unit 40 without being affected by delays in wireless communication, the correspondence between the input information IN and the images IMGA and IMGB may be managed by frame numbers. In this case, for example, the drawing control unit 30 and the wireless control unit 31 share the input information IN and the frame number associated with the input information IN.

[0043] Then, the wireless control unit 31 transmits the transmission data TD including the input information IN and the frame number to the server device 12. In response to this, the server device 12 returns the image IMGA corresponding to the input information IN together with the frame number to the terminal device 10a. By using such a management method, it becomes possible to correctly determine the image to be displayed next based on the frame number when the two units UA and UB are switched.

[0044] <Major Effects of the First Embodiment> As described above, in the method of the first embodiment, by providing two units UA and UB and a switching unit 32 that selects one of the two units UA and UB depending on the state of the received radio wave RX, it becomes possible to display a desired image on the display device 16 regardless of the state of wireless communication. Also, by selecting the unit UA during a period when the state of wireless communication is good, the power consumption of the terminal device 10a can be reduced.

[0045] (Embodiment 2) <Outline of terminal device> Fig. 3 is a schematic diagram showing a configuration example of the main part of a terminal device according to the second embodiment. The terminal device 10b shown in Fig. 3 is different from the terminal device 10a shown in Fig. 1 in the output destination of the switching unit 32 and the configuration and operation of the GPU 35b. The switching unit 32 outputs a selection signal SL to the GPU 35b, not to the rendering control unit 30. When the unit UA is selected by the selection signal SL from the switching unit 32, the GPU 35b ignores the rendering start command GST from the rendering control unit 30.

[0046] Specifically, the GPU 35b includes a circuit that switches whether to ignore the drawing start command GST in response to, for example, a selection signal SL from the switching unit 32. When the unit UB is selected by the selection signal SL from the switching unit 32, the GPU 35b draws the image IMGB in response to the drawing start command GST from the drawing control unit 30 as usual.

[0047] By using such a configuration, the drawing control unit 30 does not need to switch between outputting and not outputting the drawing start command GST based on the selection signal SL, for example. That is, the drawing control unit 30 operates in the same manner during the period when the unit UA is selected as during the period when the unit UB is selected. On the other hand, in the configuration example shown in FIG. 1, the drawing control unit 30 needs to change its operation during the period when the unit UA is selected and the period when the unit UB is selected. A representative method for realizing this is a method of disabling the operation of the drawing control unit 30 during the period when the unit UA is selected.

[0048] However, in this case, it may be difficult to respond when stateful processing is required, such as determining an image to be displayed based on a series of input information IN. As a specific example, assume a case where the stateful processing is being performed using the unit UA and the unit is switched to the unit UB. In this case, in the configuration example shown in FIG. 1, the drawing control unit 30 is enabled at the time of switching, for example, and it is difficult to grasp the processing content of the unit UA at the previous time point.

[0049] On the other hand, when the configuration example of Fig. 3 is used, the drawing control unit 30 continues to operate regardless of whether or not there is a switch, so it can grasp the processing contents of the unit UA. As a result, even if the drawing control unit 30 switches to the unit UB in the middle of executing stateful processing using the unit UA, it can take over the processing of the unit UA while maintaining consistency. Similarly, with regard to switching from the unit UB to the unit UA, consistency can be maintained by the wireless control unit 31 operating at all times.

[0050] <Major Effects of the Second Embodiment> As described above, by using the method of the second embodiment, it is possible to obtain the same effects as those described in the first embodiment. In addition, it becomes possible to switch between the two units UA and UB while maintaining consistency.

[0051] (Embodiment 3) <Outline of terminal device> Fig. 4 is a schematic diagram showing an example of the configuration of the main part of a terminal device according to the third embodiment. The terminal device 10c shown in Fig. 4 is different from the terminal device 10b shown in Fig. 3 in the configuration and operation of a decoder 37c and a GPU 35c. The decoder 37c outputs a decoding end notification DED when decoding is completed. Specifically, the decoder 37c includes a circuit for outputting a decoding end notification DED.

[0052] When the unit UA is selected by the selection signal SL from the switching unit 32, the GPU 35c outputs a rendering end notification GED to the rendering control unit 30 in response to a decoding end notification DED from the decoder 37c after ignoring the rendering start command GST from the rendering control unit 30. Specifically, the GPU 35c includes a circuit that receives the decoding end notification DED and outputs the rendering end notification GED.

[0053] <Operation of terminal device> Fig. 5A is a timing chart showing an example of an operation that may occur when the example configuration of Fig. 3 is used as the premise of the terminal device of Fig. 4. Fig. 5A assumes that the state of wireless communication is good and a unit UA including an image reproduction unit 33 and the like is selected. In Fig. 5A, first, the input interface 21 outputs input information IN#1 for requesting an image #1 to the drawing control unit 30 and the wireless control unit 31. The drawing control unit 30 inputs the input information IN#1, prepares to have the GPU 35b draw an image IMGB#1 based on the input information IN#1, and then outputs a drawing start command GST#1 to the GPU 35b.

[0054] Here, as described in FIG. 3, the GPU 35b ignores the drawing start command GST#1 and does not perform drawing. Therefore, the GPU 35b does not output the drawing end notification GED#1 as it is. However, in general, in image processing using a GPU, the drawing control unit 30 realized by the CPU needs to wait for the drawing end notification GED from the GPU when it outputs the drawing start command GST to the GPU. In addition, after inputting the drawing end notification GED from the GPU, the drawing control unit 30 needs to output the drawing start command GST for the next image to the GPU.

[0055] 5A, the GPU 35b receives a drawing start command GST#1 from the drawing control unit 30, and then immediately outputs a drawing end notification GED#1 to the drawing control unit 30. That is, the GPU 35b is provided with a circuit for outputting such a drawing end notification GED#1.

[0056] Meanwhile, the wireless control unit 31 receives input information IN#1 in parallel with the drawing control unit 30, generates transmission data TD#1 including the input information IN#1, and outputs the data to the wireless device 24. The wireless device 24 transmits a transmission radio wave TX#1 generated by modulating the transmission data TD#1 to the server device 12 (not shown). In response to this, the wireless device 24 receives a reception radio wave RX#1 from the server device 12. The wireless device 24 demodulates the reception radio wave RX#1, and outputs reception data RD#1 including the encoded image IMGAe#1 to the image playback unit 33.

[0057] The image playback unit 33 inputs the received data RD#1 and acquires the image IMGAe#1 contained in the received data RD#1. Then, the image playback unit 33 causes the decoder 37 to decode the image IMGAe#1. As a result, the decoder 37 restores the original image IMGA#1 and stores the image IMGA#1 as frame data FRM#1 in the external memory 22. The time t1 when the image IMGA#1 is stored in the external memory 22 can be said to be the time when the rendering of the image #1 in response to the request is essentially completed.

[0058] Here, in the example of FIG. 5A, the input interface 21 outputs input information IN#2 for requesting the next image #2 at a time point prior to time point t1. The same processing as for the input information IN#1 is sequentially performed for the input information IN#2. At this time, the rendering control unit 30 has already input the rendering end notification GED#1 for image #1 from the GPU 35b before inputting the input information IN#2. Therefore, at the time of inputting the input information IN#2, the rendering control unit 30 immediately starts preparations for causing the GPU 35b to render the image IMGB#2 based on the input information IN#2.

[0059] 5A, the GPU 35b may output a rendering end notification GED#2 for image #2 to the rendering control unit 30 before time t1. This means that the rendering of the next requested image #2 is completed before time t1 when the rendering of the requested image #1 is completed.

[0060] In this manner, in the operation example of Fig. 5A, the order of images drawn by the unit UA and the unit UB may not be synchronized. As a result, when switching between the two units UA and UB occurs by the switching unit 32, there is a risk that the order of images displayed may be out of sync. Therefore, it is useful to provide a decode end notification DED as in the configuration example of Fig. 4.

[0061] Fig. 5B is a timing chart showing an example of operation when the terminal device of Fig. 4 is used. In Fig. 5B, as in Fig. 5A, the unit UA finishes drawing the requested image #1 at time t1. Also, as in Fig. 5A, the input interface 21 outputs input information IN#2 for requesting the next image #2 at a time point before time t1.

[0062] However, in Fig. 5B, unlike the case of Fig. 5A, the GPU 35c outputs a rendering end notification GED#1 for the same image #1 to the rendering control unit 30 at approximately the same time point as time point t1 when the unit UA ends the rendering of the same image #1. Similarly, the GPU 35c outputs a rendering end notification GED#2 for the same image #2 to the rendering control unit 30 at approximately the same time point as time point t2 when the unit UA ends the rendering of the image #2.

[0063] Specifically, the GPU 35c, for example, inputs a rendering start command GST#1 for image #1 from the rendering control unit 30, and then waits for a decode end notification DED#1 from the decoder 37c. Then, when the GPU 35c inputs the decode end notification DED#1, it outputs a rendering end notification GED#1 to the rendering control unit 30. As a result, it becomes possible to make the time t1 at which the rendering of the requested image #1 ends substantially equal between the two units UA and UB. As a result, it becomes possible to synchronize the order of the images to be rendered between the two units UA and UB.

[0064] Moreover, the rendering control unit 30 outputs a rendering start command GST#1 for image #1 to the GPU 35c, and then waits for a rendering end notification GED#1 from the GPU 35c. The rendering control unit 30 holds the input information IN#2 received during the period in which the rendering control unit 30 waits for the rendering end notification GED#1 in the internal memory 36, a register, or the like. Then, from the point in time when the rendering control unit 30 receives the rendering end notification GED#1 from the GPU 35c, the rendering control unit 30 starts preparations for causing the GPU 35c to render the next image IMGB#2 based on the input information IN#2. This allows the CPU and GPU to operate in a general operating manner.

[0065] FIG. 5C is a timing chart showing an operation example different from that of FIG. 5B when the terminal device of FIG. 4 is used. Unlike FIG. 5B, FIG. 5C shows an operation example when the state of wireless communication is poor. Unlike FIG. 5B, in FIG. 5C, the operation of the wireless device 24, the image reproduction unit 33, and the decoder 37c is stopped. Also, unlike FIG. 5B, the GPU 35c does not ignore the drawing start command GST#1 from the drawing control unit 30, but actually draws the image IMGB#1 in response to the drawing start command GST#1.

[0066] Then, at time t3 when the GPU 35c finishes rendering of the image IMGB#1, it outputs a rendering end notification GED#1 to the rendering control unit 30 and stores the rendered image IMGB#1 as frame data FRM#1 in the external memory 22. This time t3 depends on the relative relationship between the rendering time in the GPU 35c and the time required from when the server device 12 is instructed to render the image to when restoration of the image is completed, but can usually be close to time t1 shown in Fig. 5B.

[0067] <Major Effects of the Third Embodiment> As described above, the method of the third embodiment can also provide the same effects as those described in the first and second embodiments. In addition, it is possible to synchronize the order of images to be drawn between the two units UA and UB. As a result, when switching between the two units UA and UB occurs, it is possible to accurately maintain the order of images to be displayed.

[0068] The invention made by the present inventor has been specifically described above based on the embodiments, but the present invention is not limited to the above-mentioned embodiments and can be modified in various ways without departing from the gist of the invention. For example, the above-mentioned embodiments have been described in detail to easily explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0069] 12 Server device (external device) 15 Display control device 16 Display device 21 Input Interface 23 Detector 24 Radio equipment 30 Drawing control section 31 Radio control unit 32 Switching section 33 Image playback section 35,35b,35c GPU 37,37c decoder DED decoding completion notification GED drawing completion notification GST drawing start command IMGA,IMGB images IMGAe encoded image IN Input information RX Received radio wave SL Selection signal TX Transmitted radio wave UA,UB Unit

Claims

1. A display control device that wirelessly communicates with an external device and displays an image corresponding to input information on a display device, a wireless control unit that transmits the input information to the external device via wireless communication to cause the external device to draw a first image corresponding to the input information; a first unit that acquires the first image drawn by the external device via wireless communication and displays the first image on the display device; a second unit including a GPU, causing the GPU to render a second image corresponding to the input information, and causing the display device to display the second image rendered by the GPU; a switching unit that judges whether a received radio wave is in a good state or a bad state, and selects the first unit when the judgement result is the good state, and selects the second unit when the judgement result is the bad state; Equipped with The first unit includes: an image reproduction unit that acquires, via wireless communication, the first image that is rendered by the external device and then encoded; a decoder that decodes the first image acquired by the image reproduction unit; Equipped with the second unit includes, in addition to the GPU, a drawing control unit that outputs a drawing start command based on the input information; The GPU renders the second image in response to the rendering start command from the rendering control unit; the rendering control unit outputs the rendering start command to the GPU even when the first unit is selected by the switching unit; When the first unit is selected by the switching unit, the GPU ignores the drawing start command from the drawing control unit. Display control device.

2. 2. The display control device according to claim 1, the decoder outputs a decode end notification when the decode ends; when the first unit is selected by the switching unit, the GPU outputs a rendering end notification to the rendering control unit in response to the decoding end notification from the decoder after ignoring the rendering start command from the rendering control unit. Display control device.

3. 2. The display control device according to claim 1, further comprising: an input interface that receives an input from a user and generates the input information; a wireless device that wirelessly communicates with the external device; A detector for detecting a state of the received radio wave; having Display control device.

4. 3. The display control device according to claim 2, the input information is first input information, The drawing control unit is receiving second input information during a period waiting for the rendering end notification from the GPU after outputting the rendering start command to the GPU; in response to the rendering end notification, starting preparations for causing the GPU to render a next image based on the second input information; Display control device.

5. 2. The display control device according to claim 1, the display control device and the display device are mounted on a vehicle, The external device is a server device. Display control device.

6. A display control device that wirelessly communicates with an external device and displays an image corresponding to input information on a display device, Equipped with a CPU and a GPU, The CPU includes: transmitting the input information to the external device via wireless communication to cause the external device to draw a first image corresponding to the input information; Determine whether the received radio wave is in good or bad condition, When the determination result is the good state, the first image drawn by the external device is acquired via wireless communication, and the first image is displayed on the display device; When the determination result is the defective state, causing the GPU to draw a second image corresponding to the input information and causing the display device to display the second image; The CPU outputs a drawing start command to the GPU even if the determination result is the good state; When the determination result is the good state, the GPU ignores the drawing start command from the CPU. Display control device.

7. 7. The display control device according to claim 6, Further, a decoder for decoding the first image that is rendered by the external device and then encoded, the decoder outputs a decode end notification when the decode ends; when the determination result is the good state, the GPU outputs a drawing end notification to the CPU in response to the decoding end notification from the decoder after ignoring the drawing start command from the CPU. Display control device.

8. 7. The display control device according to claim 6, further comprising: an input interface that receives an input from a user and generates the input information; a wireless device that wirelessly communicates with the external device; A detector for detecting a state of the received radio wave; having Display control device.

9. 8. The display control device according to claim 7, the input information is first input information, The CPU includes: receiving second input information during a period waiting for the rendering end notification from the GPU after outputting the rendering start command to the GPU; in response to the rendering end notification, starting preparations for causing the GPU to render a next image based on the second input information; Display control device.

10. 7. The display control device according to claim 6, the display control device and the display device are mounted on a vehicle, The external device is a server device. Display control device.

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