JPH08265663A - Image composite device and digital broadcast receiver - Google Patents

Abstract

PURPOSE: To easily and suitably select one arbitrary image in composite display. CONSTITUTION: An SDTV signal separated by a separate circuit 5 is decoded by decoders 7 to 10, and its picture element is converted in conversion circuits 11 to 14 such as magnification and reduction of the image including an arbitrary aspect ratio according to a control signal from a synthesis control circuit 15. The SDTV signal converted by the conversion circuits 11 to 14 is fed to a synthesis circuit 16 in which the signal is synthesized in terms of area. Furthermore, an arbitrary identification signal from a viewer is fed to the synthesis control circuit 15 through an input terminal 3 and a control circuit 4. The identification corresponds to the SDTV signal decoded by the decoders 7 to 10. The operation of the conversion circuits 11 to 14 and the synthesis circuit 16 is controlled by the input of the identification signal and the display of the SDTV signal commanded by the identification signal is magnified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image synthesizing apparatus and a digital broadcast receiver suitable for use in receiving digital television broadcasting, for example.

[0002]

2. Description of the Related Art For example, digital television broadcasting using broadcasting satellites has been carried out. In such digital television broadcasting, a transmission capacity of, for example, about 20 Mbps is provided for each channel, and it is designed so that so-called high definition television (HDTV) signals can be transmitted.

Therefore, for example, when transmitting a conventional standard definition television (SDTV) signal in such digital television broadcasting, one SDTV signal is compressed to about 5 Mbps by a technique such as image compression. It is possible to transmit four SDTV signals by the above-mentioned 1-channel broadcasting. Therefore, in the current digital television broadcasting, it is carried out to transmit four SDTV signals by one-channel broadcasting.

That is, in this case, on the transmitting side, for example, 4
Each of the SDTV signals has a vertical resolution (effective scanning line number) of 480 (pixels) and a horizontal resolution (effective horizontal pixel number) of 720 pixels. And these SDTV
Each signal is encoded by a motion compensation DCT encoding method or the like, and each is compressed to about 5 Mbps. Further, header information, synchronization information, etc. for identification are added to these compressed coded data, and four pieces of coded data added with these information and the like are multiplexed to obtain about 20 Mbps.
A bit string of is formed.

After this bit string is QPSK-modulated by a predetermined modulation carrier, for example, a modulated radio wave is transmitted toward a broadcasting satellite. When broadcasting is performed on a plurality of channels, for example, the above-mentioned multiplexed bit string of about 20 Mbps is formed for each channel, and after these bit strings are QPSK-modulated by different modulation carriers, respectively, For example, the modulated radio wave is transmitted toward the broadcasting satellite.

Conventional digital broadcast receivers receive such digital television broadcasts as shown in FIG. 6, for example. That is, the radio wave retransmitted from the above-mentioned broadcasting satellite is received by a receiving antenna such as a parabolic antenna (not shown) and supplied to the antenna terminal 101. Then, the signal from the antenna terminal 101 is supplied to the demodulator 102.

Further, an arbitrary selection signal or the like from the viewer is supplied to the control circuit 104 through the input terminal 103. Then, the control signal from the control circuit 104 is supplied to the demodulator 102, and the demodulator 1 is operated according to the input selection signal or the like.
The channel selected for demodulation at 02 and the SDTV signal to be decoded from that channel are selected.

Further, the demodulated signal of the selected SDTV signal is supplied to the decoder 105 and, for example, one of four SDTV signals transmitted in one selected channel is transmitted.
One is decrypted. Then, this decoded signal is supplied to the D / A conversion circuit 106 and converted into an analog signal, and the converted analog signal is taken out to the output terminal 107.

Thus, in the above-described conventional digital broadcast receiver, the channel selected by the viewer is demodulated by the demodulator 102, and the SDTV signal selected from the demodulated one channel is decoded by the decoder 105. Output to the output terminal 107. This output terminal 10
A monitor receiver or the like (not shown) is connected to 7, and the video signal taken out to the output terminal 107 is displayed.

[0010]

By providing a plurality of decoders 105 in parallel in such a digital broadcast receiver, a plurality of SDTV signals transmitted in the same channel can be obtained at the same time. Therefore, it has been considered to synthesize and display a plurality of such SDTV signals on one screen. Such a display can be effectively used, for example, as a reference when a viewer selects an SDTV signal. However, in this case, conventionally, there has been no control means for easily and accurately selecting an arbitrary SDTV signal from the displayed ones.

That is, in the conventional television receiver, for example, one screen called picture-in-picture is reduced and the other screen is combined and displayed. In this case, one screen is selected by erasing the other reduced screen. Furthermore, when selecting another screen in this example, the screen is replaced with the other screen so that the one screen is reduced and synthesized and displayed in the other screen, and then the one screen is erased. To do. Therefore, for such selection, two control means for exchanging screens and erasing reduced screens are used.

Therefore, if such two means are applied to the selection of the SDTV signal of the digital television broadcast, for example, four SDTV signals are obtained from one channel in the digital television broadcast. Therefore, when such four SDTV signals are combined into the same size by dividing the screen into four, it is impossible to deal with the above two means.

In recent years, in a so-called wide screen receiver, the screen is divided into left and right and the two screens are combined and displayed in the same size. In this case as well, sound is emitted from a speaker, for example. The priority of the screen is determined by the selection of the voice, and when the division is stopped, only the screen for which the voice is selected is displayed. Therefore, also in this case, two control means for stopping the selection and division of audio are used, and similarly to the above, it is not possible to deal with selection of, for example, four SDTV signals of digital television broadcasting. there were.

In addition, for example, in the above-mentioned digital television broadcasting, it is considered to use the four SDTV signals broadcast on the above-mentioned one channel in an integrated manner.
Thus, for example, in a relay of a baseball or the like, an SDTV signal of an image of a normal relay (main image) and an SD of an image of a pitcher, a batter, a runner, or the like individually taken.
It is conceivable to perform various new forms of broadcasting such as transmitting TV signals respectively.

When viewing such a broadcast, the viewer can display, for example, four SDTV signals evenly, display only one arbitrary SDTV signal, and display four STV signals.
Various display methods such as displaying one of the DTV signals larger than the other three are required. Even such a display method cannot be dealt with by the above-mentioned conventional control means.

This application has been made in view of such a point, and the problem to be solved is arbitrary, for example, from a plurality of SDTV signals broadcast on one channel in digital television broadcasting. In the past, there has been no control means for easily and appropriately selecting the SDTV signal.

[0017]

For this reason, in the present invention, a plurality of images corresponding to a plurality of input video signals are generated in one image.
In an image synthesizing device for synthesizing and displaying on one screen, when an identification signal of an arbitrary number is input, an image corresponding to the number is used by using an identification signal representing a number corresponding to each of a plurality of images. The input image signals are combined so that they are displayed larger than the image.

[0018]

According to this, when a plurality of images are combined and displayed on one screen, any one of the images can be easily and accurately selected.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described. The present invention relates to an image synthesizing apparatus for synthesizing and displaying a plurality of images respectively corresponding to a plurality of input video signals on one screen. An identification signal having a means for inputting an identification signal indicating a combination form of images, a means for outputting a combination control signal based on the identification signal, and a means for combining a plurality of input video signals based on the combination control signal Represents a number corresponding to each of a plurality of images, and when an arbitrary number is input,
An image synthesizing device characterized by synthesizing a plurality of input video signals so that an image corresponding to the number is displayed larger than other images.

Therefore, FIG. 1 shows an image synthesizing apparatus according to the present invention, for example, a digital television broadcast (about 20 Mbp).
FIG. 3 is a block diagram showing an example of a configuration of an apparatus applied when a plurality of SDTV signals (480 vertical pixels (pixels), horizontal 720 pixels, about 5 Mbps) are broadcast through a broadcasting satellite in 1 channel in s). In FIG. 1, a signal from a receiving antenna (not shown) such as a parabolic antenna is supplied to the antenna terminal 1, and a signal from the antenna terminal 1 is supplied to the demodulator 2.

A selection signal or the like from an arbitrary remote control device (not shown) from a viewer is supplied to the control circuit 4 through the input terminal 3. Then, the control signal formed by the control circuit 4 is supplied to the demodulator 2, and the channel demodulated by the demodulator 2 is selected in accordance with the input selection signal or the like. As a result, the demodulator 2 demodulates the above-mentioned bit string of about 20 Mbps transmitted on an arbitrary channel selected according to the input selection signal or the like.

The demodulated signal demodulated by the demodulator 2 is supplied to the separation circuit 5. Further, an information signal such as header information inserted in the bit string from the demodulator 2 is supplied to the information judging section 6, and for example, information on the number of SDTV signals in the demodulated channel is judged. Then, the information on the number of SDTV signals is supplied to the separation circuit 5, and the coded data (each about 5 Mbps) of, for example, four SDTV signals in the demodulated channel is separated.

The SDTV signals separated by the separating circuit 5 are supplied to decoders 7, 8, 9, and 10, respectively. Further, the SDTV signals decoded by these decoders 7 to 10 are supplied to the pixel conversion circuits 11, 12, 13, and 14, respectively. In each of the conversion circuits 11 to 14, pixel conversion such as enlargement or reduction of an image including arbitrary vertical and horizontal scaling is performed according to a control signal from a synthesis control circuit 15 described later.
Then, the SDT converted by these conversion circuits 11 to 14
The V signal is supplied to the synthesis circuit 16.

Then, in the synthesizing circuit 16, the converting circuits 11 to 14 are responsive to the control signal from the synthesizing control circuit 15.
The SDTV signals converted by are combined area-wise. That is, each of the conversion circuits 11 to 14 described above is provided with an image memory, and these memories are read at a predetermined timing, and the read image data is switched by the synthesizing circuit 16, so that these images are spread over an area. Is synthesized. Further, the combined digital signal is supplied to the D / A conversion circuit 17 to be converted into an analog signal, and the converted analog signal is taken out to the output terminal 18.

Therefore, in this device, for example, in the relay of the above-mentioned baseball, the image of the normal relay (main image)
When the SDTV signal of the image obtained by individually photographing the pitcher, the batter, the runner, etc. is transmitted together with the SDTV signal of, the screen is equally divided into four as shown in A of FIG. One image (main, pitcher, batter, runner) can be combined and displayed for each division.

In this case, if the connected monitor receiver has a high-definition screen having, for example, 1080 effective scanning lines (pixels) and 1440 effective horizontal pixels, for example, conversion is performed. Without converting the number of pixels in the circuits 11 to 14, the SDTV signals having the resolution of 480 pixels in the vertical direction and 720 pixels in the horizontal direction are directly combined in the vertical and horizontal directions to form a screen of 960 vertical pixels and 1440 horizontal pixels. , All the transmission images can be displayed by leaving 120 pixels (scan lines) in the vertical direction.

Therefore, in this device, an arbitrary identification signal from the viewer from the above-mentioned remote control device (not shown) or the like is supplied to the synthesis control circuit 15 through the input terminal 3 and the control circuit 4. This identification signal corresponds to, for example, each of the SDTV signals decoded by the decoders 7 to 10 described above. Then, the operations of the conversion circuits 11 to 14 and the synthesizing circuit 16 are controlled by the input of the identification signal, and the display of the SDTV signal instructed by the identification signal is enlarged.

That is, for example, as shown in FIG. 2A, the images on the respective screens, which are equally divided into four parts, are numbered as upper left 1, upper right 2, lower left 3, and lower right 4, respectively, and the above-mentioned identification signal is added to these. Set to represent a number. And for example 1
When the identification signal of the number is input, for example, the conversion circuit 11 corresponding to the image on the screen on the upper left 1 performs the interpolation calculation of the filter processing for enlarging the vertical and horizontal directions of the image, and other conversion. The circuits 12 to 14 perform a thinning operation for reducing the vertical and horizontal directions of the image.

Then, the enlarged image and the reduced image are combined in area by the combining circuit 16. As a result, for example, as shown in B of FIG. 2, the image on the screen on the upper left 1 is enlarged, the images on the other screens 2 to 4 are reduced, and the image on the screen 1 is made larger than the other images. The enlarged display is performed. Similarly, when the identification signals of the numbers 2 to 4 are input, the image of the screen of the input number is displayed larger than the other images as shown in B to B of FIG.

Further, for example, as shown in B of FIG.
For example, when the identification signal of the number 1 is input again from the display state in which the image on the screen is larger than the other images, for example, the conversion circuit 11 corresponding to the image on the screen on the upper left 1
At this time, the interpolation calculation of the filtering process for doubling the image in the vertical and horizontal directions is performed, and the interpolated calculation, for example, vertical 960 is performed.
Only the image of pixels and horizontal 1440 pixels is passed through the synthesizing circuit 16, and, for example, only the image of this one screen is enlarged and displayed as shown by C in FIG.

Similarly, when the same identification signal is input again from the states of (1) to (3) in FIG.
As shown in C to C, only the image on the screen designated by the identification signal is enlarged and displayed. When different identification signals are input from the display states of B to C of FIG. 2, the displays of B to B of FIG. 2 corresponding to the identification signals are respectively displayed. Further, as the identification signal, an identification signal of, for example, 0 number which does not correspond to the division number of the above-mentioned screen is set, and when the identification signal of 0 number is inputted, the display of A of FIG. 2 is performed. To be done.

Therefore, in this apparatus, for example, when an arbitrary SDTV signal is selected from a plurality of SDTV signals broadcast on one channel in digital television broadcasting, an identification indicating a number corresponding to each of a plurality of images is identified. By using the signal, a plurality of input video signals are combined so that an image corresponding to the identification number is displayed larger than other images when an identification signal of the arbitrary number is input Can be selected easily and accurately.

The control of the combination of the display screens using the above-mentioned identification signal can be carried out by the processing shown in the flowchart of FIG. 3, for example. In FIG. 3, the numbers of the display patterns used in the figure correspond to the display forms shown in FIG. 2, respectively, and the pattern 0 is the pattern A in FIG. 2 and the patterns 1-1 to 1-4. Are respectively shown in Figure 2.
B-, patterns 2-1 to 2-4 are respectively shown in FIG.
It corresponds to C of.

Then, when the operation is started by turning on the power or switching the channel, the parameter S is set to 0 in step [1] and 0 of the display pattern is selected in step [2]. As a result, a control signal according to the selected display pattern is supplied to the conversion circuits 11 to 14 and the synthesizing circuit 16, the operation of which is controlled and a display as shown in A of FIG. 2 is performed.

Further, in step [3], it is judged whether or not an arbitrary identification signal is inputted, and while it is not inputted, this step [3] is repeated. When the identification signal is input, steps [4] [5] [6] [7]
In [8], the number of the identification signal (identification number) is determined. When the identification number is 0, the steps from [4] to

Go to [9], this step

The display pattern 0 is selected in [9]. Further, in step [10], the parameter S is set to the identification number, and in step [3]
Returned to.

When the identification number is 1, step [5]
To Step [11]. Then, in this step [11], it is judged whether or not the parameter S and the identification number match, and if they do not match, the display pattern 1-1 is selected in step [12]. Further steps [1
In step 3], the parameter S is set to the identification number and the process returns to step [3]. If they match in step [11], the display pattern 2-1 is selected in step [14], and the parameter S is set to 0 in step [15] and returned to step [3].

As a result, the pattern 1-1 is displayed when the identification signal with the number 1 is first input. When the identification signal with the number 1 is input again, the pattern 2-1 is displayed. When the identification signal with the number 1 is input again (three consecutive times), the pattern 1-1 is displayed again, and the display of B of FIG. 2 and the display of C of FIG. 2 are repeated alternately. Is done.

Similarly, when the identification number is 2, the process proceeds from step [6] to step [16]. Then, in this step [16], it is judged whether or not the parameter S and the identification number match, and if they do not match, the step [1
7], the display pattern 1-2 is selected. Further, in step [18], the parameter S is set to the identification number and the process is returned to step [3]. If they match in step [16], the display pattern 2-2 is selected in step [19], and the parameter S is set to 0 in step [20].
And is returned to step [3].

When the identification number is 3, step [7]
To step [21]. Then, in this step [21], it is judged whether or not the parameter S and the identification number match, and if they do not match, the display pattern 1-3 is selected in step [22]. Further steps [2
In step 3], the parameter S is set to the identification number and the process returns to step [3]. If they match in step [21], 2-3 of the display patterns are selected in step [24], and the parameter S is set to 0 in step [25] and returned to step [3].

When the identification number is 4, the process proceeds from step [8] to step [26]. Then, in this step [26], it is judged whether or not the parameter S and the identification number match. If they do not match, the step [2
7], 1-4 of display patterns are selected. Further, in step [28], the parameter S is set to the identification number and the process is returned to step [3]. If they match in step [26], the display pattern 2-4 is selected in step [29], and the parameter S is set to 0 in step [30].
And is returned to step [3].

Thus, according to the above-described image synthesizing device, in the device for synthesizing and displaying the plurality of images corresponding to the plurality of input video signals on one screen, the identification signal indicating the synthesizing form of the plurality of images is generated. It has a means for inputting, a means for outputting a synthesizing control signal based on the identification signal, and a means for synthesizing a plurality of input video signals based on the synthesizing control signal, and the identification signal is a number corresponding to each of the plurality of images. Represents
By combining multiple input video signals so that the image corresponding to that number is displayed larger than other images when an arbitrary number is input, It is possible to easily and accurately select any one of the images.

The above-mentioned device is applied when a plurality of images respectively corresponding to a plurality of input video signals are synthesized and displayed on one screen. For example, as shown in the above-mentioned embodiment, digital This is particularly effective when applied to a case where an arbitrary SDTV signal is selected in a digital broadcasting receiver that receives a plurality of SDTV signals broadcast on one channel in television broadcasting.

Further, in the above-described embodiment, the display shown in FIG. 2B is performed when the identification signals with the numbers 1 to 4 are first input, and the display is performed when the identification signals with the same number are input again. Although the display indicated by C in 2 is performed, the order may be reversed. In that case, the synthesis control is performed in steps [11] [16] [21] in the flowchart of FIG. 3, for example.
The steps of [12] and [14], [17] and [19], [22] and [24], [27] and [29] are performed for the display pattern selection processing after the judgment of coincidence and non-coincidence in [26]. Then you can reverse them.

Further, in the above-mentioned embodiment, the number of images to be synthesized and displayed is four, but when this number is two, for example, FIG.
And as shown in FIG. That is, FIG. 4 shows a display mode. When the number of images is two, in the case of displaying a uniform screen corresponding to A in FIG. 2 described above, for example, the screen is displayed as shown in A in FIG. The display is divided into two parts, left and right. Further, in the display of the screen in which one image corresponding to B in FIG. 2 described above is made larger than other images,
For example, picture-in-picture display is adopted as shown in FIG. Further, in the display of the screen of only one image corresponding to C in FIG. 2 described above, the display as shown in C in FIG. 4 is adopted.

When the number of images is 2, the control of the synthesis of the display screen using the identification signal can be performed by the process shown in the flowchart of FIG. 5, for example. In FIG. 5, the numbers of the display patterns used in the figure correspond to the display forms shown in FIG. 4, respectively, and the pattern 0 is the pattern A in FIG.
Patterns 1 and 1-2 of FIG.
Reference numerals 1 and 2-4 correspond to those in C of FIG. 4, respectively.

When the operation is started by turning on the power or switching the channel, the parameter S is set to 0 in step [31], and the display pattern 0 is selected in step [32]. Thereby, the control signals according to the selected display pattern are converted into the conversion circuits 11, 1
2 and the synthesizing circuit 16 and the operation thereof is controlled to display, for example, as shown in A of FIG.

Further, in step [33], it is judged whether or not an arbitrary identification signal is inputted, and while it is not inputted, this step [33] is repeated. When an identification signal is input, steps [34] [35] [3
6], the number of the identification signal (identification number) is determined. When the identification number is 0, the process proceeds from step [34] to step [37], and the display pattern 0 is selected in this step [37]. Further steps [3
In step 8], the parameter S is set to the identification number and the process returns to step [33].

When the identification number is 1, step [3
5] to step [39]. Then, in this step [39], it is judged whether or not the parameter S and the identification number match, and if they do not match, the step [40]
The display pattern 1-1 is selected with. Further, in step [41], the parameter S is set to the identification number and the process is returned to step [33]. If they match in step [39], the display pattern 2-1 is selected in step [42], and the parameter S is set to 0 in step [43] and returned to step [33].

As a result, when the identification signal with the number 1 is first input, the pattern 1-1 is displayed. When the identification signal with the number 1 is input again, the pattern 2-1 is displayed. When the identification signal with the number 1 is input again (three consecutive times), the pattern 1-1 is displayed again, and the display of B of FIG. 4 and the display of C of FIG. 4 are alternately repeated. Is done.

Similarly, when the identification number is 2, the process proceeds from step [36] to step [44]. Then, in this step [44], it is judged whether or not the parameter S and the identification number match, and if they do not match, the step [4]
5], the display pattern 1-2 is selected. Further, in step [46], the parameter S is set to the identification number and the process is returned to step [33]. If there is a match in step [44], the display pattern 2-2 in step [47] is displayed.
Is selected, the parameter S is set to 0 in step [48], and the process returns to step [33].

In this way, even when the number of images is 2, a plurality of input video signals are combined by the same processing as in the case where the number of images is 4, and an arbitrary one of them is selected. Can be performed easily and accurately. Further, even when the number of images is 3, or when the number is 5 or more, the above-mentioned device is applied to easily and appropriately combine a plurality of input video signals and select any one of them. You can

Therefore, in the above-described apparatus, the composition control circuit 15 is provided with composition control means (display pattern, composition control processing) according to the number of images. And the information determination unit 6
By supplying information on the number of SDTV signals in the demodulated channel to the synthesis control circuit 15, the control means can be selected according to the number of images.

Further, in the above-mentioned device, for example, the number of the identification signal corresponding to each image to be divided and displayed may be superimposed and displayed in the image as necessary. This makes it possible for the viewer to use it as a guide when selecting an image, and eliminates the need to specify the positional relationship between the image and the split screen, allowing more flexible split display.

[0054]

According to the present invention, when an arbitrary SDTV signal is selected from a plurality of SDTV signals broadcast on one channel in, for example, digital television broadcasting, numbers corresponding to a plurality of images respectively. By using the identification signal that represents the number of input video signals so that when the identification signal of an arbitrary number is input, the image corresponding to that number is displayed larger than other images, It has become possible to easily and accurately select one image.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an example of an image synthesizing apparatus to which the present invention is applied.

FIG. 2 is a diagram for explaining an example of the display.

FIG. 3 is a diagram for explaining the control.

FIG. 4 is a diagram for explaining another example of the display.

FIG. 5 is a diagram for explaining the control.

FIG. 6 is a configuration diagram for explaining a conventional image synthesizing apparatus.

[Explanation of symbols]

 2 Demodulator 3 Input terminal 4 Control circuit 7-10 Decoder 11-14 Pixel conversion circuit 15 Combining control circuit 16 Combining circuit

Claims (12)

[Claims] 1. An image synthesizing device for synthesizing and displaying a plurality of images respectively corresponding to a plurality of input video signals on one screen, a means for inputting an identification signal indicating a synthesizing form of the plurality of images, It has means for outputting a combination control signal based on the identification signal, and means for combining the plurality of input video signals based on the combination control signal, wherein the identification signal is a number corresponding to each of the plurality of images. The image synthesizing apparatus synthesizes the plurality of input video signals so that when the arbitrary number is input, the image corresponding to the number is displayed larger than other images. 2. The image synthesizing apparatus according to claim 1, wherein the identification signal represents a number corresponding to each of the plurality of images, and when the same number is input twice consecutively, the identification signal corresponds to the number. An image synthesizing apparatus characterized in that only the above image is displayed. 3. The image synthesizing apparatus according to claim 2, wherein the identification signal is provided with an arbitrary identification signal that does not correspond to the plurality of images, and when an arbitrary identification signal that does not correspond to the images is input. An image synthesizing apparatus which synthesizes the plurality of input video signals so that the plurality of images are displayed in the same size. 4. An image synthesizing device for synthesizing and displaying a plurality of images respectively corresponding to a plurality of input video signals on one screen, a means for inputting an identification signal indicating a synthesizing form of the plurality of images, It has means for outputting a combination control signal based on the identification signal, and means for combining the plurality of input video signals based on the combination control signal, wherein the identification signal is a number corresponding to each of the plurality of images. The image synthesizing apparatus is characterized in that, when an arbitrary number is input, only the image corresponding to the number is displayed. 5. The image synthesizing apparatus according to claim 4, wherein the identification signal represents a number corresponding to each of the plurality of images, and when the same number is input twice consecutively, the identification signal corresponds to the number. An image synthesizing apparatus that synthesizes the plurality of input video signals so that the image is displayed larger than other images. 6. The image synthesizing apparatus according to claim 5, wherein the identification signal is provided with an arbitrary identification signal that does not correspond to the plurality of images, and when an arbitrary identification signal that does not correspond to the images is input. An image synthesizing apparatus which synthesizes the plurality of input video signals so that the plurality of images are displayed in the same size. 7. A digital broadcast receiver for receiving a digital broadcast in which video signals of a plurality of programs are transmitted to one channel, and a plurality of decoders for decoding the video signals of the plurality of programs, respectively. Means for synthesizing a plurality of decoded video signals obtained from a plurality of decoders, means for inputting an identification signal indicating a synthesizing form of the plurality of decoded video signals, and the synthesizing means based on the identification signals And a means for outputting a composite control signal for controlling the, the identification signal represents a number corresponding to each of the plurality of images, when any of the numbers are input, the image corresponding to the number A digital broadcast receiver characterized by synthesizing the plurality of input video signals so as to be displayed larger than other images. 8. The digital broadcast receiver according to claim 7, wherein the identification signal represents a number corresponding to each of the plurality of images, and when the same number is input twice in succession, A digital broadcast receiver characterized in that only the corresponding images are displayed. 9. The digital broadcast receiver according to claim 8, wherein the identification signal is provided with an arbitrary identification signal that does not correspond to the plurality of images, and an arbitrary identification signal that does not correspond to the images is input. In the digital broadcast receiver, the plurality of input video signals are combined so that the plurality of images are displayed in the same size. 10. A digital broadcast receiver for receiving a digital broadcast in which video signals of a plurality of programs are transmitted to one channel, and a plurality of decoders for decoding the video signals of the plurality of programs, respectively. Means for synthesizing a plurality of decoded video signals obtained from a plurality of decoders, means for inputting an identification signal indicating a synthesizing form of the plurality of decoded video signals, and the synthesizing means based on the identification signals And a means for outputting a composite control signal for controlling the above, wherein the identification signal represents a number corresponding to each of the plurality of images, and when any of the numbers is input, only the image corresponding to the number is input. A digital broadcast receiver characterized by being displayed. 11. The digital broadcast receiver according to claim 10, wherein the identification signal represents a number corresponding to each of the plurality of images, and when the same number is input twice in succession, A digital broadcast receiver, characterized in that the plurality of input video signals are combined so that the corresponding image is displayed larger than other images. 12. The digital broadcast receiver according to claim 11, wherein an arbitrary identification signal that does not correspond to the plurality of images is provided in the identification signal, and an arbitrary identification signal that does not correspond to the images is input. In the digital broadcast receiver, the plurality of input video signals are combined so that the plurality of images are displayed in the same size.