Patent Publication Number: US-2011058100-A1

Title: Video signal processing apparatus and video signal processing method

Description:
CROSS-REFERENCE TO THE INVENTION 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2009-208685, filed on Sep. 9, 2009; the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a video signal processing apparatus and a video signal processing method for example. 
     2. Description of the Related Art 
     With the start of terrestrial digital broadcast, there are commercialized many television apparatuses (hereinafter, referred to as “HDTV”) having large-sized screen liquid crystal flat panels (hereinafter, referred to as “full HD panel”) capable of full specification high definition display. 
     The HDTV has an external video signal input terminal such as an HDMI terminal and a D terminal, and input of a game video of a portable video game player to the D terminal for example enables display of the game video in a large-sized screen so that the game can be enjoyed. 
     Meanwhile, a resolution of a game video outputted by a portable video game player is a resolution (480×272 pixels) for example, and a resolution of a D terminal is 480 P (720×480 progressive). 
     Therefore, the HDTV obtains a video (hereinafter, referred to as “D 2  original image”) of 720×480 pixels (aspect ratio 3:2) having a black area surrounding the game video. 
     It should be noted that this black area is generated by a black signal outputted by the portable video game player. 
     If the D 2  original image is simply displayed dot by dot, a game video of a small-sized screen having a black frame is set in a full HD panel, and a scaling processing such as enlargement is generally performed. 
     However, since the D 2  original image (aspect ratio 3:2) of an input origin and the full HD panel (aspect ratio 16:9) have different aspect ratios, simply enlarged display of lateral and longitudinal pixels deteriorates a circularity ratio, flattening the video and generating a sense of incompatibility in viewing. 
     As a technology for displaying while maintaining a circularity ratio in a case that an aspect ratio of a video of an input origin and an aspect ratio of a display panel are different as above, there is disclosed a video signal processing apparatus enabling display of a high-quality video even when a resolution of an input video and a resolution of a display apparatus are different by setting a sampling frequency of a digital video signal to have a sampling number which does not require digital data to be scaled in a horizontal direction in accordance with a horizontal resolution of the display apparatus for example (see JP-A 2006-227442 (KOKAI) for example). 
     BRIEF SUMMARY OF THE INVENTION 
     However, in a case of the above-described conventional technology, though the technology about aspect ratios of 4:3 to 16:9 and 16:9 to 4:3 are described, a technology for enlargedly displaying a peculiar video of a portable video game player inputted to a D terminal is not described, and there is a problem that such a video cannot be enlargedly displayed with a circularity ratio being maintained. 
     The present invention is made to solve such a problem and its object is to provide a video signal processing apparatus and a video signal processing method in which a video inputted to an external video signal input terminal is enlargedly displayed with a circularity ratio being maintained and a high-quality video without image degradation can be displayed. 
     A video signal processing apparatus according to an aspect of the present invention includes: a receiver configured to receive input of a predetermined video display mode; a video converter configured to generate video data by sampling a video signal with a predetermined resolution inputted from the outside at an arbitrary sampling frequency and scaling the area corresponding to an enlargement scaling factor of the generated video data at an arbitrary enlargement ratio; and a controller configured to control, when the input of the predetermined video display mode is received by the receiver, the sampling frequency and the enlargement ratio of scaling to enlarge the area in the video data having almost the same aspect ratio as an aspect ratio of a display panel at a rate of an integral multiple or n/2-times (n is an integer). 
     A video signal processing method according to an aspect of the present invention includes: receiving input of a predetermined video display mode; controlling, when the input of the predetermined video display mode is received, a sampling frequency and an enlargement ratio of scaling to enlarge the area corresponding to an enlargement scaling factor in video data having almost the same aspect ratio as an aspect ratio of a display panel at a rate of an integral multiple or n/2-times (n is an integer) and generating video data by sampling a video signal with a predetermined resolution inputted from the outside at the controlled sampling frequency and scaling the area of the generated video data at the controlled enlargement ratio. 
     According to the present invention, it is possible to enlargedly display a video inputted to an external video signal input terminal while maintaining a circularity ratio and to display a high-quality video without image degradation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a constitution of a video signal processing apparatus of an embodiment of the present invention. 
         FIG. 2  is a diagram showing an example of a video menu. 
         FIG. 3  is a diagram showing an example of a game screen menu. 
         FIG. 4  is a diagram showing a D 2  original image. 
         FIG. 5  is a diagram showing a display example of a video of a portable video game player enlarged to four times (4×). 
         FIG. 6  is a diagram showing a display example of a video of a portable video game player enlarged to three times (3×). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a television apparatus of an embodiment according to a video signal processing apparatus of the present invention will be described in detail with reference to the drawings. 
       FIG. 1  is a diagram showing a constitution of the television apparatus. 
     As shown in  FIG. 1 , the television apparatus of this embodiment has a remote controller  1  (hereinafter, referred to as “RC  1 ”) as a manipulation unit, a video signal processing unit  2 , and a large-sized screen liquid crystal flat panel  3  (hereinafter, referred to as “full HD panel  3 ”) capable of full specification high vision display. 
     The manipulation unit can be a button provided in a TV main body other than the RC  1 . 
     The full HD panel  3  has a screen of a full HD size (1920×1080 pixels) (aspect ratio 16:9). 
     This screen has a resolution of at least twice the number of vertical-direction lines of an input image of a D terminal of 720×480 pixels (aspect ratio 3:2), and can draw a video with an arbitrarily designated number of horizontal and vertical display pixels. 
     This screen can draw the video with the arbitrarily designated number of horizontal and vertical display pixels. 
     The video outputted from the video signal processing unit  2  is displayed in the screen of the full HD panel  3 . 
     In this screen, the video outputted from the video signal processing unit  2  is displayed. 
     The RC  1  is connected to the video signal processing unit  2  by radio communication such as infrared communication. 
     Multiple buttons for manipulating functions housed in the television apparatus are provided in the RC  1 . 
     A command is issued from an infrared transmitter (not shown) of the RC  1  by manipulation of the desired button. 
     A CPU  20  accepts this command via an infrared receiver  10  of the video signal processing unit  2  and performs a processing corresponding to the command. 
     By button manipulation of a video menu of the RC  1  for example, as shown in  FIG. 2 , the CPU  20  displays a video menu  30  in which setting items are longitudinally laid out in the screen of the full HD panel  3 . 
     As the setting items of the video menu  30 , there are, for example, “automatic”, “brilliant”, “standard”, “movie”, “TV professional”, “movie professional”, “game”, “PC fine”, “memory” and so on. 
     When a viewer designates the setting item such as “game”  31  in the video menu with the RC  1 , the CPU  20  stores “game mode” as an operation mode in a memory  19 , and performs screen control in “game mode”. 
     Viewer&#39;s manipulation of the button of a game screen menu of the RC  1  during this “game mode” makes the CPU  20  display a game screen menu  32  shown in  FIG. 3 . 
     Three screen setting items such as “game normal”, “portable zoom  1 ”, “portable zoom  2 ” are cyclically displayed in the game screen menu  32 . 
     Every time a user manipulates the button for designating the item in the RC  1 , the item of the screen setting changes to the next item, so that a desired screen can be set. 
     In other words, the game screen menu  32  is a screen setting menu dedicated to games, for designating an angle of view (size of the game screen) of a game video in “game mode”. 
     The game screen menu  32  shown here is only an example and other examples can be thought of. 
     The item “game normal” is a setting to display a video (hereinafter referred to as “D 2  video”) inputted to a D terminal  11  almost without modification. 
     The D 2  video is a video of 720×480 pixels (aspect ratio 3:2). 
     A video of a portable game player is of 272×480 pixels (aspect ratio 16:9). 
     As shown in  FIG. 4 , the D 2  video is a video in a state that a video  41  of the portable video game player is pasted in a center and the area of a difference is filled with black pixels. This is called a D 2  original image. 
     The item “portable zoom  1 ” is a setting to enlargedly display each of a lateral size and a longitudinal size of the portable video game player video to three times (3×). 
     The item “portable zoom  2 ” is a setting to enlargedly display each of the lateral size and the longitudinal size of the portable video game player video to four times (4×). 
     In this menu, though items of three screen settings are cyclically repeated, the setting items can be longitudinally laid out so that the setting item can be selected by button manipulation in a longitudinal direction, similarly to in the video menu  30  shown in  FIG. 2  above. 
     The video signal processing unit  2  has the infrared receiver  10 , the D terminal  11 , a low pass filter (LO)  12 , an analog/digital converter  13  (hereinafter, referred to as “A/D converter  13 ”), an I/P converter  14 , a scaling module  15 , an image quality processing module  16 , a video converter  17 , a panel I/F  18 , a memory  19 , the CPU  20  and so on. 
     The infrared receiver  10  receives the command of button manipulation issued from the RC  1  and transmits to the CPU  20 . 
     The D terminal  11  is a video signal input terminal into which analog component terminals are united and through which a type (number of scan lines, frame rate, I/P information (information of interlace signal/progressive signal), aspect ratio, and the like) of the video can be transmitted from a control line, as format information of the video. 
     A D terminal cable from the portable video game player for example is connected to the D terminal  11  and an analog video signal of a resolution of 480 P (720×480 progressive) is inputted thereto. Hereinafter, this video signal is referred to as a D 2  original video  40 . 
     The low pass filter (LO)  12  is a band filter filtering off an unnecessary band at a time of sampling data from the analog video signal (D 2  original video  40 ) inputted from the D terminal  11 . 
     In other words, the low pass filter (LO)  12  passes a frequency band necessary for sampling a video according to Nyquist theorem. 
     The A/D converter  13  samples the video signal of the band having been passed by the low pass filter (LO)  12  with a sampling frequency designated by the CPU  20 , converts the video signal into digital video data, and stores in the memory  19 . 
     In this example, in “game normal”, “portable zoom  1 ”, and “portable zoom  2 ”, video signals are sampled at 27 MHz (one time; 1×) and converted into digital video data. 
     In other words, the A/D converter  13  samples an analog video signal of a predetermined resolution inputted from the outside with a designated sampling frequency, thereby generating digital video data. 
     The I/P converter  14 , by a control signal  102  from the CPU  20 , reads the digital video data stored in the memory  19 , and converts an I (interlace) signal into a P (progressive) signal. 
     In a case of a game video, since an original video signal is a progressive signal, I/P conversion is not performed in this example. 
     The scaling module  15 , by designation of a scaling factor by a control signal  103 , reads the progressive video via the I/P converter  14  from the memory  19  and performs a scaling processing, that is, controls a scaling factor of enlargement or reduction of the video or controls filtering such as edge correction by a scaling filter, and stores in the memory  19 . 
     In the game mode, since the screen of the full HD panel  3  is large in relation to the D 2  original video  40 , the video is controlled to be enlarged. 
     Information of the area corresponding to an enlargement scaling factor is set in the scaling module  15  in advance, and by a designation of a scaling factor from the CPU  20 , the area corresponding to the enlargement scaling factor is enlarged. 
     For example, it is set to enlarge the area of 480×270 pixels in a case of four times (4×) and to enlarge the area of 640×360 pixels in a case of three times (3×). 
     The image quality processing module  16 , by a designation by a control signal  104 , reads the scaled video from the memory  19  and adjusts an image quality, that is, performs a gamma correction, an image quality correction and the like of the video and outputs to the panel I/F  18 . 
     The panel I/F  18  is an interface drawing (outputting) the video via the image quality processing module  16  in the screen of the full HD panel  3 , and converts the video into a signal format compliant to a panel standard. 
     A video converter  17  includes the A/D converter  13 , the I/P converter  14  and the scaling module  15 , and sets the sampling frequency and controls I/P conversion as well as the enlargement ratio of the video by the designations by the control signals  101 ,  102 ,  103 , thereby enlarging a part of the area of the D 2  original video  40  to three times (3×) or four times (4×), and stores in the memory  19 . 
     In other words, the video converter  17  samples an analog video signal (video signal from the portable video game player) with a predetermined resolution inputted from the outside in a horizontal direction and a vertical direction at a sampling frequency controlled by the CPU  20 , thereby generating digital video data, and scales the generated video data at an enlargement ratio controlled by the CPU  20 . 
     For example, when “portable zoom  2 ” is set in “game mode”, a portion ((480×270 pixels) this is referred to as “game video frame”) of almost the same range as that of a game video  41  (480×272 pixels) in a central portion of the D 2  original video  40  is enlarged to four times (4×) (at a rate of an integral multiple) (see  FIG. 5 ). 
     Meanwhile, when “portable zoom  1 ” is set in “game mode”, a portion (game video  43  with a black frame) of the area (640×360 pixels) including the game video  41  in the central portion of the D 2  original video  40  and a part of a black pixel area is enlarged to three times (3×) (at a rate of an integral multiple) (see  FIG. 6 ). 
     It should be noted that aspect ratios in both cases of three times (3×) and four times (4×) enlargement are almost 16:9. 
     The memory  19  is a dynamic RAM or the like and is a temporary storage place of the video data being processed. 
     Further, the memory  19  functions as a working area in which the CPU  20  processes data. 
     The CPU  20  functions as a receiver receiving input of a predetermined video display mode (in a case that “portable zoom  2 ” is selected and inputted in the setting of “game mode” or in a case that “portable zoom  1 ” is selected and inputted in the setting of “game mode”). 
     Further, the CPU  20  outputs the control signals  101 ,  102 ,  103 ,  104  to the above-described respective modules and performs control for drawing the video in the screen of the full HD panel  3 . 
     More specifically, when the operation mode is “game mode” and “portable zoom  2 ” is designated in the game screen menu for example, the CPU  20  controls the respective modules as below. 
     To the A/D converter  13 , the CPU  20  outputs the control signal  101  to set a frequency of a sampling clock in a horizontal valid period at 27 MHz (one time; 1×), to import 720 pixels of horizontal valid pixels and to import 480 lines (one time; 1×) with regard to the vertical direction. 
     To the scaling module  15 , the CPU  20  outputs the control signal  103  to enlarge the game video frame of the game video  41  imported in the memory  19  to four times (4×), and not to turn on the scaling filter when the enlargement ratio is integral multiple, that it not to perform filtering such as edge correction either in the horizontal or the vertical direction. 
     If the operation mode is “game mode” and “portable zoom  1 ” is inputted in the game screen menu for example, the CPU  20  controls the respective modules as below. 
     To the A/D converter  13 , the CPU  20  outputs the control signal  101  to set the frequency of the sampling clock in the horizontal valid period at 27 MHz (one time; 1×), to import 720 pixels of horizontal valid pixels and to import 480 lines (one time; 1×) with regard to the vertical direction. 
     To the scaling module  15 , the CPU  20  outputs the control signal  103  to enlarge the area (see  FIG. 5 ) of the game video  43  with the black frame imported in the memory  19  to three times (3×), and not to perform filtering in the horizontal direction or in the vertical direction when the enlargement ratio is integral multiple or n/2-times (n is an integer). 
     Further, to the image quality processing module  16 , the CPU  20  outputs the control signal  104  to perform image quality adjustment (gamma correction, image quality correction and the like) as usual. 
     In other words, when the input of the predetermined video display mode (“game mode” and “portable zoom  1 ” or “game mode” and “portable zoom  2 ”) is received, the CPU  20  controls the sampling frequency of the video converter  17  and the enlargement ratio of scaling to enlarge the area corresponding to an enlargement scaling factor in the video data (D 2  original video  40 ), the area having almost the same aspect ratio (16:9) as that of the full HD panel  3 , at a rate of an integral multiple or n/2-times (n is an integer). 
     It should be noted that the area corresponding to the enlargement scaling factor means the area  42  of  FIG. 5  when the enlargement scaling factor is four times (4×) for example, and the area  43  of  FIG. 6  when the enlargement scaling factor is three times (3×). 
     Subsequently, an operation of this television apparatus will be described with reference to  FIG. 5  and  FIG. 6 . 
     In this television apparatus, when a game video (for example 480 P) is inputted to the D terminal  11 , A/D conversion is performed after band filtering. 
     Thereafter, the video to which scaling and image quality adjustment are performed is displayed in the full HD panel  3 . 
     Conventionally, when a control signal  101  is inputted from a CPU  20  to an A/D converter  13 , the A/D converter  13  sets a sampling clock at 27 MHz and samples data from an input video, so that a D 2  original video  40  is imported in a memory  19  at an angle of view of 720×480 pixels (aspect ratio 3:2). 
     When a screen size of a display panel is of full HD size (1920×1080 pixels) (aspect ratio 16:9), in dot-by-dot display at 720×480 pixels (aspect ratio 3:2), a display size of a game video in relation to a screen size of a display panel is quite small, and in addition, the aspect ratio of 3:2 of the game video is different from the aspect ratio of 16:9 of the display panel, and consequently a circularity ratio of the game video is deteriorated. 
     Thus, usually, in order that image conversion is always performed both horizontally and vertically to video data imported into the memory  19 , the CPU  20  outputs control signals  103 ,  104  to a scaling module  15  and an image quality processing module  16 , thereby performing scaling and filtering uniformly to the video data. 
     Thereafter, a predetermined image quality processing is performed in an image quality processing module  16  and the video data is outputted to a full HD panel  3 , and consequently the game video inputted to the full HD panel  3  is enlargedly displayed, but image blurring occurs. 
     Thus, in this embodiment, a display setting dedicated to games such as “portable zoom  1 ” and “portable zoom  2 ” described below is prepared. 
     First, a display operation of “portable zoom  2 ” will be described with reference to  FIG. 5 . 
     When the operation mode of the screen control is set to “game mode” in the video menu (see  FIG. 2 ) and “portable zoom  2 ” is set (designated) in the game screen menu (see  FIG. 3 ), the CPU  20  outputs a control signal  101  to the A/D converter  13  to set a frequency of a sampling clock in a horizontal direction at 27 MHz and to import 480 lines with the number thereof unchanged with regard to a vertical direction. 
     Further, the CPU  20  outputs a control signal  103  to the scaling module  15  to perform scaling (enlargement control) of the video at an enlargement ratio of four times (4×) laterally and longitudinally and not to perform filtering (not to turn on the scaling filter) when the enlargement ratio is an integral multiple. 
     As a result of this control, the A/D converter  13  sets a frequency of a sampling clock in a horizontal valid period to 27 MHz and performs sampling of 720 times in a horizontal valid period of 26.66 μs. 
     Thereby, a horizontal valid pixel is sampled at 720 pixels and, with regard to a vertical direction, sampling at 480 lines is performed. 
     The sampled D 2  original video  40  is, as shown in  FIG. 4 , a video of 720×480 pixels formed by surrounding a periphery of the game video of 480×272 pixels with black pixels. 
     In other words, the D 2  original video  40  is a video of 720×480 pixels in which the game video (480×272 pixels) is pasted in a central portion. 
     Then, the scaling module  15  scaling (enlargement) processes a portion of the game video frame  42  (480×270 pixels) in the D 2  original video  40  to four times (1920×1080 pixels) both laterally and longitudinally, and stores in the memory  19 . 
     The image quality processing module  16  performs an image quality processing set in advance such as a gamma correction and an image quality correction. 
     The panel I/F  18  outputs the game video which has been image-quality processed by the image quality processing module  16  to the full HD panel  3 . 
     As a result, as shown in  FIG. 5 , a game video  51  of 1920×1080 pixels is displayed in a display screen  52  of the full HD panel  3 . 
     On this occasion, the clipped game video frame  42  is of 480×270 pixels in relation to the game video (480×272 pixels), lacking pixels in the longitudinal direction by one in each of upper and lower directions, and when the game video is enlargedly displayed in the full HD panel, a portion of the video equivalent to one pixel is cut. 
     However, usually, in games, upper and lower edge portions of a video are not used, and the above is effective when it is desired to enlarge a game video as largely as possible for viewing. 
     Next, a display operation of “portable zoom  1 ” will be described with reference to  FIG. 6 . 
     When the operation mode of the screen control is set to “game mode” in the video menu (see  FIG. 2 ) and “portable zoom  1 ” is set (designated) in the game screen menu (see  FIG. 3 ), the CPU  20  outputs a control signal  101  to the A/D converter  13  to set a frequency of the sampling clock at 27 MHz. 
     Further, the CPU  20  outputs a control signal  103  to the scaling module  15  to perform scaling of the area  43  (hereinafter referred to as “game video  43  with a black frame”) of a black frame of 640×360 pixels in the central portion of the D 2  original video  40  to three times (3×) both laterally and longitudinally. 
     By the input of the control signal  101 , the A/D converter  13  performs sampling, and the D 2  original video  40  shown in  FIG. 4  is obtained. 
     The processings above are the same as those in the case of four times (4×) enlargement. 
     The scaling module  15  performs a scaling (enlargement) processing to the game video  43  (640×360 pixels) with a black frame in which the game video (480×272 pixels) of the D 2  original video  40  is included, thereby making the area  43  with a black frame be three times (3×) both laterally and longitudinally to be of a full HD size (1920×1080 pixels), and stores in the memory  19 . 
     Then, the image quality processing module  16  performs a predetermined image quality processing such as a gamma correction and an image quality correction and outputs to the panel I/F  18 . 
     The panel I/F  18  converts the game video  43  with a black frame which has been inputted from the image quality processing module  16  into a signal format compliant with a panel standard and outputs to the full HD panel  3 . 
     As a result, as shown in  FIG. 6 , there is a black pixel area  53  in the screen  52  of the full HD panel  3  and the game video  51  is displayed in a central portion thereof. 
     An angle of view of the game video  51  at three times (3×) enlargement becomes 1440×816 pixels (aspect ratio 16:9), and in this case the circularity ratio is also maintained. 
     In this example of three times (3×) enlargement, there is an effect that, in a case that a full HD panel  3  is a large-sized screen of 52 inches or more for example and a viewer is too close to a screen for playing a game, a game screen can be displayed at an appropriate size and a game video becomes easy to be viewed. 
     As described above, according to the television apparatus of this embodiment, when the operation mode of the screen control is set to “game mode” and “portable zoom  2 ” is designated in the game screen menu, the A/D converter  13  imports the video signal from the D terminal at a ratio of one time (1×) and the scaling module  15  enlarges the portion of the game video screen  42  (480×270 pixels) among the imported D 2  original video  40  to four times (4×). 
     Further, when the operation mode of the screen control is set to “game mode” and “portable zoom  1 ” is designated in the game screen menu, the A/D converter  13  imports the video signal from the D terminal  11  at a rate of one time (1×) and the scaling module  15  enlarges the portion of the game video  43  (640×360 pixels) with a black frame among the imported D 2  original video  40  to three times (3×). 
     Thereby, it is possible to enlargedly display a game video in a full HD panel  3  without deteriorating an aspect ratio of a D 2  original video inputted from a portable video game player to a D terminal  11 . 
     Further, since video data is enlarged at a rate of an integral multiple or n/2-times (n is an integer), image quality is not degraded, thereby it is possible to display a realistic game video created by a game creator. 
     In other words, it is possible to display a game video while maintaining an original aspect ratio (lateral/longitudinal ratio) of 16:9 and a circularity ratio of a video (480×272 pixels) of a portable video game player. 
     Further, since an image quality processing is not performed to a game video, contour portions of the video can be displayed clearly. 
     In other words, by performing enlarged display while maintaining a circularity ratio of a video of a portable video game player inputted to a D terminal  11  and displaying a high quality game video without image quality deterioration in a full HD panel  3 , a viewer can enjoy a realistic game video with texture of dots. 
     It should be noted that the present invention is not limited to the above-described embodiment but a component can be modified in a practical phase without departing from the range of the gist of the present invention. 
     In the above-described embodiment, three modes of “game normal”, “portable zoom  1 ”, and “portable zoom  2 ” are provided, but it suffices that only either one of “portable zoom  1 ” and “portable zoom  2 ” is provided. 
     In the above-described embodiment there is described an example in which in a case of display of four times (4×) the A/D converter  13  imports the video data to one time (1×) and the scaling module  15  enlarges the imported video data to four times (4×), but other than the above the following combinations are possible. 
     For example, the A/D converter  13  imports the video data to two times (2×) and the scaling module  15  enlarges the imported video data to two times (2×), or the A/D converter  13  imports the video data to four times (4×) and scaling is not performed to the imported video data having been imported to four times (4×) (video data is not enlarged). 
     Further, in the above-described embodiment there is described an example in which in a case of display of three times (3×) the A/D converter  13  imports the video data at a rate of one time (1×) and the scaling module  15  enlarges the imported video data to three times (3×), but other than the above the following combinations are possible. 
     For example, the A/D converter  13  imports the video data to two times (2×) and the scaling module  15  enlarges the imported video data to one and a half times, or the A/D converter  13  imports the video data to three times (3×) and scaling is not performed to the imported video data (video data is not enlarged). 
     As describe above, various combinations of scaling factors of the A/D conversion and scaling are possible. 
     It should be noted that in enlarging a horizontal resolution, heightening a sampling frequency of A/D conversion by a designation by a control signal  101  and lowering an enlargement ratio of scaling by a designation by a control signal  103  restrain degradation of an image quality in scaling, so that an image quality of a game video can be improved. 
     Further, it is possible to realize each component described in the above-described embodiment by a program installed in a storage such as a hard disk device of a computer. 
     Further, it is possible to make a computer realize a function of the present invention by storing the above-described program in a computer-readable electronic medium and making the computer read the program from the electronic medium. 
     As an electronic medium, for example, storage medium such as a CD-ROM, flash memory, removable medium and the like are included. 
     Further, it is possible to realize the function of the present invention by storing the components dispersedly in different computers connected via a network and communicating among computers in which the respective components are functioned. 
     Other Embodiments 
     By properly combining a plurality of components disclosed in the above-described embodiment, various inventions can be constituted. For example, some components can be deleted from the entire components shown in the embodiment. 
     In other words, the embodiment of the present invention is not limited to the above-described embodiment and can be expanded and modified, and the expanded or modified embodiment is included in the technical range of the present invention.