Information processing device, information processing method, and program

Abstract

An information processing device for drawing a display frame image to be displayed by a display device (14) and transmitting the drawn display frame image to the display device (14) in either a fixed-frame-rate operation mode or a variable-frame-rate operation mode, wherein, when drawing a display frame image, transmitting the drawn display frame image to the display device (14) in the variable-frame-rate operation mode, and causing the display device (14) to display a moving image including content that was already drawn during drawing of the display frame image, the operation mode is switched to the fixed-frame-rate operation mode.

Description

[Technical Field]

[0001] The present invention relates to an information processing device, an information processing method, and a program for generating an image to be displayed on a screen of a display device. [Background technology]

[0002] Generally, display devices such as home television sets display video by continuously updating still images (frame images) displayed on the screen at a predetermined cycle (refresh rate). Therefore, an information processing device that generates video to be displayed on the display device must render each frame image that constitutes the video at a fixed frame rate that matches this refresh rate. However, a fixed frame rate can lead to problems such as not being able to fully utilize the rendering capabilities of the information processing device, or, conversely, display disturbances such as stuttering and tearing can occur if the rendering capabilities of the information processing device are insufficient.

[0003] Therefore, video standards such as HDMI (registered trademark) have proposed a technology called variable refresh rate (VRR), which allows the refresh rate of a display device to be variable. This technology allows the display device to update the displayed image at any refresh rate, so the information processing device can dynamically change the frame rate according to its own drawing speed, etc., allowing it to draw frame images at a more desirable frame rate. Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described technology, the information processing device updates frame images at a frame rate that changes depending on its own drawing speed, etc. However, in some cases, updating frame images at such a variable frame rate may not be appropriate.

[0005] The present invention has been made in consideration of the above-mentioned situation, and one of its objectives is to provide an information processing device, an information processing method, and a program that can update frame images that constitute a video using an appropriate method depending on the situation. [Means for solving the problem]

[0006] An information processing device according to one aspect of the present invention is an information processing device that draws a display frame image to be displayed on a display device and transmits it to the display device in either a fixed frame rate or a variable frame rate operating mode, and is characterized in that it includes: a frame image drawing unit that draws the display frame image and transmits the drawn display frame image to the display device in a variable frame rate operating mode; and an operating mode switching unit that switches the operating mode of the frame image drawing unit to a fixed frame rate operating mode when a moving image including content that has already been drawn is to be displayed on the display device when drawing the display frame image.

[0007] An information processing method according to one aspect of the present invention is an information processing method for drawing a display frame image to be displayed on a display device and transmitting it to the display device in either a fixed frame rate or a variable frame rate operating mode, and is characterized by including: a frame image drawing step for drawing the display frame image and transmitting the drawn display frame image to the display device in a variable frame rate operating mode; and an operating mode switching step for switching the operating mode in the frame image drawing step so that the display frame image is transmitted to the display device at a fixed frame rate when a moving image including content that has already been drawn is to be displayed on the display device when drawing the display frame image.

[0008] A program according to one aspect of the present invention is a program for causing a computer that draws display frame images to be displayed on a display device and transmits them to the display device in either a fixed frame rate or a variable frame rate operating mode to execute the following steps: a frame image drawing step of drawing the display frame images and transmitting the drawn display frame images to the display device in a variable frame rate operating mode, and an operating mode switching step of switching the operating mode so that the display frame images are transmitted to the display device at a fixed frame rate in the frame image drawing step when a moving image including content that has already been drawn is to be displayed on the display device when drawing the display frame images. This program may be provided by being stored on a computer-readable, non-transitory information storage medium. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a schematic configuration of an information processing device according to an embodiment of the present invention; [Figure 2] 1 is a functional block diagram showing functions realized by an information processing device according to an embodiment of the present invention; [Figure 3] FIG. 10 is a diagram showing an example of a display frame image displayed on a display device. [Figure 4] FIG. 2 is a sequence diagram showing an example of a flow of processing executed by an information processing device according to an embodiment of the present invention. [Figure 5] FIG. 10 is a functional block diagram showing another example of functions realized by the information processing device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] An information processing device 10 according to one embodiment of the present invention is a home game console, a personal computer, or the like, and, as shown in Fig. 1, includes a control unit 11, a storage unit 12, and an interface unit 13. The information processing device 10 is also connected to a display device 14 and an operation device 15 so as to be able to communicate data with them.

[0012] The control unit 11 includes at least one processor such as a CPU, and executes programs stored in the storage unit 12 to perform various types of information processing. The control unit 11 may also include a computing device such as a GPU specialized for image processing. Specific examples of the processing performed by the control unit 11 in this embodiment will be described later. The storage unit 12 includes at least one memory device such as a RAM, and stores the programs executed by the control unit 11 and data processed by the programs. The storage unit 12 also includes a buffer memory that temporarily stores frame images, which will be described later.

[0013] The interface unit 13 is an interface for data communication between the display device 14 and the operation device 15. The information processing device 10 is connected to the display device 14 and the operation device 15 via the interface unit 13 either wired or wirelessly. Specifically, the interface unit 13 includes a multimedia interface for transmitting a video signal supplied by the information processing device 10 to the display device 14. In particular, in this embodiment, the interface unit 13 includes an interface capable of transmitting a video signal in accordance with a standard compatible with a variable refresh rate, such as HDMI. The interface unit 13 also includes a data communication interface for receiving an operation signal indicating the content of an operation input by a user from the operation device 15. The interface unit 13 may further include a communication interface for transmitting and receiving data to and from another computer via a communication network, such as the Internet.

[0014] The display device 14 is a home television receiver, a monitor device for a personal computer, or the like, and displays an image based on the video signal received from the information processing device 10. In particular, in this embodiment, the display device 14 supports variable refresh rate technology, and updates the frame images displayed on the screen at any timing determined according to a synchronization signal included in the video signal supplied by the information processing device 10. In other words, the display device 14 can update the frame images displayed at a dynamically changing refresh rate rather than at a predetermined fixed refresh rate.

[0015] The operation device 15 is a device for accepting operation inputs from the user of the information processing device 10, and may be, for example, a controller for a home game console, a keyboard, a mouse, etc. The operation device 15 has operation members such as buttons and a touchpad for accepting operation inputs from the user, and transmits operation signals indicating the content of the operation inputs from the user to the operation members to the information processing device 10.

[0016] Functions realized by the information processing device 10 in this embodiment will be described below with reference to the functional block diagram of FIG. 2. As shown in the diagram, the information processing device 10 functionally comprises a drawing command issuing unit 21, a frame image drawing unit 22, and an operation mode switching unit 23. These functions are realized by the control unit 11 executing one or more programs stored in the storage unit 12. These programs may be provided to the information processing device 10 via a communication network such as the Internet, or may be provided to the information processing device 10 by storing them on an information storage medium such as an optical disc.

[0017] The drawing command issuing unit 21 determines the content of a frame image to be displayed on the screen of the display device 14 (hereinafter referred to as a display frame image), and issues the drawing command to the frame image drawing unit 22. The drawing command issuing unit 21 is realized by an application program such as a game program. As an example, when executing the processing of a game in which a character is controlled in a virtual space, the drawing command issuing unit 21 determines the positions and states of various objects placed in the virtual space, as well as the viewpoint position, and issues a drawing command to draw the state of the virtual space.

[0018] The drawing command issuing unit 21 repeatedly issues drawing commands for such display frame images by continuously executing loop processing. As a result, the frame images displayed on the screen of the display device 14 are updated sequentially and presented to the user as video. As mentioned above, because the display device 14 supports a variable refresh rate, the drawing command issuing unit 21 does not need to issue drawing commands at regular intervals, and can appropriately issue a drawing command for the next display frame image to be displayed when the frame image drawing unit 22 finishes drawing the display frame image.

[0019] In response to the drawing command received from drawing command issuing unit 21, frame image drawing unit 22 draws a display frame image to be displayed on the screen of display device 14, and transmits a video signal including data of the drawn display frame image to display device 14. Frame image drawing unit 22 may be realized by a program independent of the program that realizes drawing command issuing unit 21, such as a graphics library or a game engine.

[0020] The frame image drawing unit 22 updates the display frame image in either a variable frame rate or fixed frame rate operation mode. Here, updating the display frame image means that the frame image drawing unit 22 starts transmitting the drawn display frame image to the display device 14, and makes it possible to draw the next display frame image.

[0021] Specifically, if the program implementing the drawing command issuing unit 21 or the connected display device does not support a variable refresh rate, the frame image drawing unit 22 updates the display frame image at a fixed frame rate. In this case, the frame image drawing unit 22 transmits the display frame image drawn in response to the drawing command to the display device 14 at a predetermined frame rate at fixed time intervals.

[0022] On the other hand, if a display device 14 that supports a variable refresh rate is connected and the program that realizes the drawing command issuing unit 21 is a program that supports drawing at a variable frame rate, the frame image drawing unit 22 updates the display frame images at the variable frame rate. In this case, the frame image drawing unit 22 transmits the sequentially drawn display frame images to the display device 14 each time drawing of a display frame image is completed, without waiting for the lapse of a predetermined time.

[0023] In either operating mode, the drawing command issuing unit 21 executes processing to issue a drawing command for the next display frame image at the timing when the frame image drawing unit 22 updates the display frame image. This allows the drawing command issuing unit 21 to continue issuing drawing commands in a cycle that matches the timing when the display frame image is updated, regardless of which operating mode the frame image drawing unit 22 is operating in.

[0024] Here, the drawing command issuing unit 21 may cause the display device 14 to display moving images that include portions that have already been drawn when the frame image drawing unit 22 itself draws the frame images for display in real time, such as moving images prepared in advance or moving images provided from outside the information processing device 10. In this way, moving images that are to be displayed on the display device 14 but in which frame images that should be included in the frame images for display have already been drawn at the timing when the frame image drawing unit 22 draws the frame images for display will hereinafter be referred to as drawn moving images.

[0025] Specifically, the rendered video may include video (saved video) that has been encoded in advance and stored in advance in a storage device such as a hard disk drive or solid state drive connected to the information processing device 10. For example, the rendering command issuing unit 21 may display a video of a movie scene stored in the storage device when a predetermined event occurs during game execution. The rendering command issuing unit 21 may also simultaneously display a video showing game hints, etc., in a partial area of ​​the display screen along with the game screen that the user is playing.

[0026] 3 shows an example of a display frame image in which the content of the stored video is included in part of the screen. In this example, the content of the stored video is included in area A, which occupies a portion of the entire display frame image displayed on display device 14. In this case, frame image drawing unit 22 draws the content to be displayed in real time across the entire screen based on drawing commands from drawing command issuing unit 21, and generates a display frame image by arranging frame images that make up the stored video in the positions of area A.

[0027] Generally, stored video is video created in advance at a fixed frame rate. Therefore, if display frame images containing the content of the stored video are rendered at a variable frame rate, the timing at which each frame image constituting the stored video is displayed may differ from the timing at which it was created.

[0028] Furthermore, the rendered moving images may include moving images (distributed moving images) that are distributed to the information processing device 10 from a computer other than the information processing device 10 via a communication network. For example, the information processing device 10 may receive, via the communication network, moving images that represent game screens being played by other players connected online, separate from the game screens being played by the user of the information processing device 10, and display them on the screen of the display device 14. In this case, the rendering and distribution by the computer that is the distributor and the reception and display by the information processing device 10 are executed in parallel.

[0029] Even when distribution is performed in real time, the information processing device 10 sequentially receives frame images of the distributed video drawn by the source computer and includes them in the display frame images. That is, when the contents of the distributed video are displayed on the screen of the display device 14, the display frame images drawn by the frame image drawing unit 22 include frame images of the distributed video already drawn by the source computer. In this case, the frame images constituting the distributed video are not necessarily drawn at timings synchronized with the timings at which the frame image drawing unit 22 draws the display frame images. Specifically, the distributed video is drawn by the source computer at a fixed frame rate or a variable frame rate. In either case, the video is encoded in a given format and distributed to the information processing device 10. Therefore, even if the distributed video is drawn at a variable frame rate by the source computer, it is difficult for the information processing device 10 to update the display frame images at a frame rate synchronized with the original frame rate.

[0030] As described above, when a rendered moving image is included in the display targets, the contents of the rendered moving image may not be displayed properly in a variable frame rate operating mode in which a drawing command for a new display image is issued upon completion of a drawing process. This is because the rendered moving image is a moving image generated in advance at a fixed frame rate or a moving image generated at a frame rate that differs from the time required for drawing a display frame image in information processing device 10.

[0031] Therefore, in the information processing device 10 according to this embodiment, the operation mode switching unit 23 issues a switching command to switch the operation mode of the frame image drawing unit 22 as necessary. The drawing command issuing unit 21 and the operation mode switching unit 23 may be realized by the same program.

[0032] Specifically, when the drawing command issuing unit 21 determines that the contents of the drawn moving image are to be displayed, the operation mode switching unit 23 issues an operation mode switching command to the frame image drawing unit 22 requesting that the frame image drawing unit 22 operate at a fixed frame rate. This switching command may be implemented by calling an API provided by the program that implements the frame image drawing unit 22, for example.

[0033] Thereafter, drawing command issuing unit 21 periodically issues drawing commands for a screen including the drawn moving image. In response to these commands, frame image drawing unit 22 updates the display frame image, including the content of the drawn moving image, at a fixed frame rate and displays it on the screen of display device 14. As described above, drawing command issuing unit 21 issues the next drawing command in accordance with the timing of the update of the display frame image by frame image drawing unit 22, so that drawing command issuing unit 21 can continue to execute the loop process of issuing drawing commands without knowing which operating mode frame image drawing unit 22 is operating in.

[0034] This command to switch to a fixed frame rate may include information specifying the value of the frame rate after switching. When such a command to switch is received, the frame image rendering unit 22 thereafter updates the display frame images at time intervals according to the specified frame rate value.

[0035] Furthermore, when the drawing command issuing unit 21 finishes displaying the drawn moving image, the operation mode switching unit 23 may issue a switching command to the frame image drawing unit 22 to switch the operation mode from a fixed frame rate to a variable frame rate. In this way, the frame image drawing unit 22 can resume updating the display frame images at the variable frame rate.

[0036] Note that when the frame image rendering unit 22 receives an instruction to switch the operating mode, it may change the frame rate in stages rather than immediately switching and completely changing the frame rate. For example, when a command to switch to a fixed frame rate that includes specifying a frame rate value is received, if the fixed frame rate after the change differs from the most recent frame rate by a given threshold or more, the frame image rendering unit 22 may change the frame rate in stages by a predetermined amount so as to gradually change to the specified frame rate value.

[0037] An example of the flow of processing executed by the information processing device 10 according to this embodiment will be described below with reference to the sequence diagram of FIG.

[0038] First, execution of an application program that realizes drawing command issuing unit 21 is started by a user's operation input to operating device 15. Thereafter, drawing command issuing unit 21 executes the processing of the application program while issuing a drawing command for each frame in order to display the processing results on the screen of display device 14 (S1).

[0039] The frame image drawing unit 22 receives a drawing command from the drawing command issuing unit 21 and executes drawing processing for the frame image (S2). At this time, the frame image drawing unit 22 updates the display frame image in an operating mode determined according to the type of program, predetermined settings, and the like. Here, the frame image drawing unit 22 updates the display frame image at a variable frame rate. Therefore, upon finishing drawing the display frame image, the frame image drawing unit 22 immediately starts transmitting the drawn display frame image to the display device 14 and notifies the drawing command issuing unit 21 that the display frame image update is complete (S3). Upon receiving this notification, the drawing command issuing unit 21 executes processing to issue a drawing command for the next display frame image. As a result, the frame rate dynamically changes depending on the time required for the frame image drawing unit 22 to draw the display frame image. While the drawn moving image is not being displayed, the display frame image update processing at the variable frame rate is repeatedly executed in the cycle from S1 to S3 as described above.

[0040] Thereafter, as the processing of the application program progresses, it is assumed that drawing command issuing unit 21 decides to display the drawn moving image on the screen of display device 14 (S4). In response to this decision, operation mode switching unit 23 issues a command to frame image drawing unit 22 to switch to a fixed frame rate (S5). Upon receiving this command, frame image drawing unit 22 switches its own operation mode to a fixed frame rate operation mode.

[0041] After switching to the fixed frame rate operating mode, a display frame image update process similar to the cycle from S1 to S3 described above is repeatedly executed. That is, the drawing command issuing unit 21 issues a drawing command including the contents of the rendered moving image (S6), and the frame image rendering unit 22 executes the display frame image drawing process in response to this drawing command (S7). At this time, the display frame image will include the frame images that make up the rendered moving image. Here, after finishing drawing the display frame image, the frame image rendering unit 22 does not immediately start transmitting the display frame image, but rather waits for the passage of a time determined by the fixed frame rate before transmitting the rendered display frame image to the display device 14 and notifying the drawing command issuing unit 21 that the display frame image update has been completed (S8).

[0042] Further, suppose that the drawing command issuing unit 21 subsequently decides to end the display of the drawn moving image (S9). In response to this decision, the operation mode switching unit 23 issues a command to switch to a variable frame rate to the frame image drawing unit 22 (S10). Upon receiving this command, the frame image drawing unit 22 switches its own operation mode to the variable frame rate operation mode. Thereafter, the display frame image is updated at the variable frame rate, similar to the cycle from S1 to S3 described above.

[0043] In the above explanation, it is assumed that all display content included in a display frame image is determined by a single application program. However, information processing device 10 may simultaneously execute multiple application programs, with the results of each of these programs being displayed on the screen of display device 14. For example, information processing device 10 may execute a game program and display the results of that program on the entire screen of display device 14, while also displaying the results of other application programs in subwindows overlaid on the results. In this case, the multiple programs each issue drawing commands, and frame image drawing unit 22 accepts the multiple drawing commands and draws a single display frame image containing those contents.

[0044] 5 is a functional block diagram showing an example of the functions realized by information processing device 10 when two application programs are executed in parallel. In the example shown in this figure, information processing device 10 executes programs P1 and P2 simultaneously, and these two programs both realize the functions of drawing command issuing unit 21 and operation mode switching unit 23. That is, program P1 realizes the functions of drawing command issuing unit 21-1 and operation mode switching unit 23-1, and program P2 realizes the functions of drawing command issuing unit 21-2 and operation mode switching unit 23-2.

[0045] The drawing command issuing units 21-1 and 21-2 issue drawing commands for images showing the processing results of their respective programs to the frame image drawing unit 22. In response to these drawing commands, the frame image drawing unit 22 draws a single frame image for display including content according to both drawing commands, and transmits it to the display device 14.

[0046] In this example, when drawing command issuing unit 21-1 determines that the contents of the drawn moving image should be included in the display content, operation mode switching unit 23-1 issues a command to switch to a fixed frame rate to frame image drawing unit 22. Similarly, when drawing command issuing unit 21-2 determines that the contents of the drawn moving image should be included in the display content, operation mode switching unit 23-2 issues a command to switch to a fixed frame rate to frame image drawing unit 22.

[0047] When the frame image rendering unit 22 receives a command to switch to a fixed frame rate from one of the programs, it switches to an operating mode in which the display frame images are updated at a fixed frame rate. At this time, the program that has not requested the switch to a fixed frame rate can also continue to issue drawing commands at appropriate timing, regardless of which operating mode the frame image rendering unit 22 is operating in, by issuing the next drawing command in accordance with the timing at which the frame image rendering unit 22 updates the display frame image.

[0048] Furthermore, if a program that issued a command to switch to a fixed frame rate later issues a command to switch to a variable frame rate, the frame image rendering unit 22 switches to the variable frame rate operating mode. If two programs both issue commands to switch to a fixed frame rate, the frame image rendering unit 22 continues operating at the fixed frame rate until both programs issue commands to switch to a variable frame rate. That is, the frame image rendering unit 22 updates the display frame images at the fixed frame rate if any one of the programs running in parallel requests operation at a fixed frame rate, and updates the display frame images at the variable frame rate only if none of the programs requests operation at a fixed frame rate. This allows the display frame images containing the contents of the rendered moving image to be updated at the fixed frame rate when a rendered moving image is displayed, regardless of which program requests the display of the rendered moving image.

[0049] As described above, according to the information processing device 10 of this embodiment, when displaying content including drawn moving images that are not appropriate for display at a variable frame rate, the display frame images can be updated at a fixed frame rate, thereby reducing display disturbances that accompany updates at a variable frame rate.

[0050] It should be noted that the embodiments of the present invention are not limited to those described above. For example, the above description has been given of an example in which one or two programs issue drawing commands, but the present invention is not limited to this, and even in cases in which three or more programs operate in parallel, the frame image drawing unit 22 operates in response to drawing commands and switching commands from each program, thereby making it possible to update the display frame images in an appropriate operating mode, either a fixed frame rate or a variable frame rate, depending on the situation.

[0051] Furthermore, the rendered moving images are not limited to those exemplified above, and the operation mode switching unit 23 may switch the operation mode when displaying various types of moving images that are preferably displayed at a fixed frame rate rather than a variable frame rate. For example, the rendered moving images may include moving images that the frame image rendering unit 22 itself has previously rendered and that have been saved in a storage device for later playback. [Explanation of symbols]

[0052] 10 information processing device, 11 control unit, 12 storage unit, 13 interface unit, 14 display device, 15 operation device, 21 drawing command issuing unit, 22 frame image drawing unit, 23 operation mode switching unit

Claims

1. An information processing device that draws a display frame image to be displayed on a display device and transmits the image to the display device in either a fixed frame rate or a variable frame rate operation mode, a frame image drawing unit that draws the display frame image and transmits the drawn display frame image to the display device in the variable frame rate operation mode; an operation mode switching unit that switches the operation mode of the frame image drawing unit to the fixed frame rate operation mode and specifies the value of the fixed frame rate when a moving image including content that has already been drawn is to be displayed on the display device when drawing the display frame image; Including, When the value of the specified fixed frame rate after switching differs from the value of the last frame rate before switching by a predetermined threshold value or more, the frame image drawing unit changes the frame rate in stages by a predetermined amount so as to gradually change to the value of the specified fixed frame rate.

1. An information processing device comprising:

2. 2. The information processing device according to claim 1, The operation mode switching unit switches the operation mode of the frame image drawing unit to the variable frame rate operation mode when the display of the moving image is to be terminated.

1. An information processing device comprising:

3. 3. The information processing device according to claim 1, The frame image drawing unit transmits the display frame images to the display device at time intervals according to the specified fixed frame rate value.

1. An information processing device comprising:

4. 2. The information processing device according to claim 1, The information processing device executes a plurality of programs simultaneously, each of the plurality of programs functions as the operation mode switching unit that switches the operation mode of the frame image drawing unit to the fixed frame rate operation mode when the program itself causes the display device to display the moving image; When at least one of the plurality of programs requests switching to the fixed frame rate operation mode, the frame image drawing unit transmits the display frame image to the display device in the fixed frame rate operation mode.

1. An information processing device comprising:

5. 2. The information processing device according to claim 1, The moving image includes a moving image that is rendered in advance and stored in a storage device connected to the information processing device.

1. An information processing device comprising:

6. 2. The information processing device according to claim 1, The moving image includes a moving image distributed from a computer other than the information processing device.

1. An information processing device comprising:

7. 1. An information processing method for drawing a display frame image to be displayed on a display device and transmitting the image to the display device in either a fixed frame rate or a variable frame rate operation mode, a frame image drawing step of drawing the display frame image and transmitting the drawn display frame image to the display device in the variable frame rate operation mode; an operation mode switching step of switching the fixed frame rate operation mode and specifying the value of the fixed frame rate so that the display frame images are transmitted to the display device at the fixed frame rate value in the frame image drawing step when a moving image including content that has already been drawn is to be displayed on the display device when drawing the display frame images; Including, When the value of the specified fixed frame rate after switching differs from the value of the last frame rate before switching by a predetermined threshold value or more, the operation mode switching step changes the frame rate stepwise by a predetermined amount so as to gradually change to the value of the specified fixed frame rate.

1. An information processing method comprising:

8. a computer that draws a display frame image to be displayed on a display device and transmits the image to the display device in either a fixed frame rate or a variable frame rate operation mode; a frame image drawing step of drawing the display frame image and transmitting the drawn display frame image to the display device in the variable frame rate operation mode; an operation mode switching step of switching the fixed frame rate operation mode and specifying the value of the fixed frame rate so that the display frame images are transmitted to the display device at the fixed frame rate value in the frame image drawing step when a moving image including content that has already been drawn is to be displayed on the display device when drawing the display frame images; A program for executing When the value of the specified fixed frame rate after switching differs from the value of the last frame rate before switching by a predetermined threshold value or more, the operation mode switching step changes the frame rate stepwise by a predetermined amount so as to gradually change to the value of the specified fixed frame rate. program.

Images