JPH07264482A - Video signal processing unit - Google Patents

Abstract

PURPOSE:To use a memory for a caption processing circuit in common with a memory for auxiliary signal processing to improve image quality. CONSTITUTION:With respect to the video signal processing unit having functions of processing plural kinds of video signals and used for displaying each of the processing outputs of the plural kinds of the video signals onto one and same display device, a memory 5 used for a caption processing circuit 1 used to display a video software of the letter box system where a laterally long image is inserted to an image whose aspect ratio is 4:3 on a display device of a laterally long screen whose aspect ratio is 2:1 or 16:9 through magnification and used for a demultiplexer circuit 2 for an auxiliary for the television system such as EDTV 2 system including the auxiliary for improving image quality is used in common by providing changeover means 3, 4 selecting the memory for the circuit 1 or the circuit 2 depending on the type of the video signal especially in this video signal processing unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing device which has a function of processing a plurality of types of video signals and is used for displaying the processed outputs of the plurality of types of video signals on the same display. Especially, the letter box type video software in which a horizontally long screen is inserted in a screen with an aspect ratio of 4: 3 has an aspect ratio of 2: 1 or 1
Separation of auxiliary signal such as horizontal high-frequency auxiliary signal performed by a television system having a subtitle processing circuit when enlarging on a display with a landscape screen such as 6: 9 and an auxiliary signal for improving image quality such as EDTV2 It is about circuits.

[0002]

2. Description of the Related Art In recent years, in addition to the television system widely used in the world such as NTSC system and PAL system, it is compatible with the system, but has resolution and S / S.
Enhanced Definition with improved N
n Television (EDTV) or EDT
V second generation system, EDTV2, Improv
d Definition Television (I
DTV), Improved PAL, Extende
Various television systems such as dPAL have been put to practical use or tested. Since these various television systems are basically compatible with each other, a plurality of these television broadcasts can be received as a television receiver.

Further, as an example of high performance which is incompatible with the conventional television system, High Definit
Ion Television (HDTV),
It is expected that some receivers for HDTV will have a configuration that integrates the functions capable of receiving the image of the current television system transiently or possibly in the future.

It is considered that the number of cases where images of various television systems are displayed on the same display as described above will increase in the future.

It is often necessary to convert software of different formats created for each of these plural types of television systems and commonly display it on a display having a screen with an aspect ratio based on one of the television systems. Occur. One of the problems in that case is conversion of television-based software having different aspect ratios.

For example, when displaying image software having an aspect ratio of 16: 9 on a display having a screen having an aspect ratio of 4: 3, non-image portions are generated at the top and bottom of the screen as shown in FIG. Called the letterbox method), many of the video software has been converted to use the non-image part of the translated subtitle display. When projecting such letterbox type video software on a landscape display with an aspect ratio of 16: 9 as shown in FIG. 5B, subtitles may be cut off when only the image part is enlarged. is there. Therefore, a caption processing circuit has been proposed which moves a caption as shown in FIG. 5B by storing the caption portion using a memory. For example, Japanese Patent Laid-Open No. 2-179
There is one described in Japanese Patent Publication No. 080.

At this time, it is necessary for the memory to store all video signals including subtitles, but the subtitles are considered to be present in the non-image portion of the lower half of the image. Therefore, the maximum number of lines in the lower half of about 130 lines is 9 pixels of 4 fsc.
10 must be stored, and the memory capacity is 910 (the number of pixels on one line) × 130 (the number of lines).
× 8 (gradation) = 946400 bits = about 1 Mbit is required.

On the other hand, EDTV2, Extended P
In a television system such as AL, an auxiliary signal necessary for improving the resolution is often multiplexed, and the auxiliary signal is demodulated on the receiving side to be used for improving the resolution. For example, EDTV2
In the broadcasting system of (1), a conjugate high hole (a gap at a target position with a color signal) is used to transmit a horizontal high frequency auxiliary signal for improving the horizontal resolution, which is multiplexed with a video signal.

In order to separate such an auxiliary signal on the receiving side, it is generally necessary to use a memory, and in order to separate the horizontal high frequency auxiliary signal of the EDTV 2 on the receiving side, it is also processed using the memory. There is. For example, "multi-dimensional signal processing of TV image" by Toshihiko Fukibuki, Nikkan Kogyo Shimbun, Ltd., page 137, a circuit as shown in FIG. At this time, it is necessary for the memory to store all video signals as much as one field of color signals. Therefore, the memory capacity is required to be 455 (the number of pixels on one line) × 262.5 (the number of lines) × 8 (grayscale) = 955500 bits = about 1 Mbit.

Therefore, conventionally, as shown in FIG. 6, a memory for the caption processing circuit and a memory for the horizontal high frequency auxiliary signal separating circuit are required.

[0011]

Since the aspect ratio of a television signal of the EDTV2 system is 16: 9,
The display will use a screen with an aspect ratio of 16: 9. As described above, the image receiving device having a display whose aspect ratio is longer than 4: 3 is characterized in that when a letter box type video signal is received, only the image portion is enlarged and displayed as described above. Since it can be exhibited, it is often the case that only the image portion is enlarged and displayed.

However, in order to realize it, both the processing of the auxiliary signal for improving the image quality and the subtitle processing are required, and as described above, it is necessary to use two memories of about 1 Mbit. Since this memory is expensive, it has the drawback of being less economical. In view of the above problems, the present invention is
Provided is a video signal processing device capable of switching between a memory of a caption processing circuit and a memory used for processing unique to a television system such as an auxiliary signal for improving image quality.

[0013]

In order to solve the above problems, a video signal processing apparatus according to the present invention is a readable / writable memory and a first processing for a video signal using the memory. Video signal processing circuit, a first three-state bus transceiver for selecting an input / output signal of the first video signal processing circuit by a first switching signal, and a second processing of the video signal by using the memory. A second video signal processing circuit, a second three-state bus transceiver for selecting an input / output signal of the second video signal processing circuit by a second switching signal, a first switching signal and a second switching And a switching circuit for generating a signal, for connecting the memory-side input / output terminals of the first and second three-state bus transceivers to the memory input / output terminals. .

That is, when there is the first and second processing in which the video signal must be processed using the memory, one memory can be shared, and the switching condition and its timing are characteristic. Is to have.

A memory for storing a video signal for sharing, a first video signal processing circuit for processing a first video signal of the video signals using the memory, and the first video First bidirectional switch means for connecting an input / output terminal of a signal processing circuit and an input / output terminal of the memory, and a second video for processing a second video signal of the video signals using the memory. A signal processing circuit, a second bidirectional switch means for connecting the input / output terminal of the second video signal processing circuit and the input / output terminal of the memory, and the first and second bidirectional switch means are controlled. And a control circuit, wherein the control circuit controls cutoff and conduction of the first and second switch means in accordance with a video signal.

In particular, the first video signal processing circuit is a caption processing circuit for moving captions, and the second video signal processing circuit can identify whether or not an auxiliary signal for improving image quality is included. The control circuit has a video signal discriminating means for discriminating the type of the video signal, and when the video signal includes an identification signal, the first both switch means is shut off and the second circuit And a video signal processing device for conducting the first bidirectional switch means and shutting off the second bidirectional switch means when the video signal does not include an identification signal. is there. As a result, the video signal processing suitable for the image software is performed and the memory amount can be reduced.

A memory for storing a video signal, a first video signal processing circuit for processing a first video signal of the video signals using the memory, and a first video signal processing circuit A bidirectional first switch means for connecting an input / output terminal and an input / output terminal of the memory, and a second processing means for processing a second video signal of the video signals by using the memory.
Controlling the video signal processing circuit, the bidirectional second switch means for connecting the input / output terminal of the second video signal processing circuit and the input / output terminal of the memory, and the first and second switch means. And a display unit for displaying the outputs of the first and second video signal processing devices. The control circuit displays the comparison result of the aspect ratio of the video signal and the aspect ratio of the screen of the display unit. Is a video signal processing device for controlling interruption and conduction of the first and second switch means in accordance with the above. As a result, the aspect ratio of the display and the aspect ratio of the video signal are compared, and it is determined whether only the image signal portion should be enlarged and displayed according to the comparison result. However, it can be realized with a configuration in which the amount of memory is reduced.

[0018]

According to the present invention, the switching circuit generates the first switching signal and the second switching signal, and the first three-state bus transceiver causes the input / output terminal of the first video signal processing circuit to output the first switching signal. And the second three-state bus transceiver selects the input / output terminal of the first video signal processing circuit by the second switching signal, and the input / output terminals of the first and second three-state bus transceivers on the memory side. By connecting the input / output terminals of the memory and the memory, one memory can be switched and used as the memory used for the video signal processing of the first and second video signal processing circuits.

[0019]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram of a video signal processing circuit showing an embodiment of the present invention. Although not shown, a video signal input to a television receiver is a current television system such as an NTSC system or a PAL system. And EDTV system, EDTV2 system, IDTV system, Im developed for improving the image quality of the current television system.
advanced PAL system, Extended PAL
It is assumed that a video signal input section capable of inputting any of various television systems such as a system is provided.

In FIG. 1, 1 is a caption processing circuit for moving captions, 2 is a horizontal high frequency auxiliary signal separation circuit capable of separating horizontal high frequency auxiliary signals which are multiplexed auxiliary signals for improving image quality, Reference numeral 3 is a first three-state bus transceiver that selects the input / output signal of the caption processing circuit 1 by a switching signal C1, and reference numeral 4 is a second three-state that selects the input / output signal of the horizontal high frequency auxiliary signal separation circuit by a switching signal C2. The bus transceiver 5 is a memory that stores either the output of the three-state bus transceiver 3 or the output of the three-state bus transceiver 4, and 6 is a switching circuit that generates switching signals C1 and C2.

The operation of the video signal processing device configured as described above will be described. ED as a display
It is assumed that a screen having an aspect ratio of 16: 9 used in the TV2 system is used.

First, in the case of a normal NTSC system or PAL system signal, in the case of a horizontally long image signal having an aspect ratio of 16: 9 or the like as a video signal, a letterbox system signal having an upper and lower non-image portion must be input. However, there is no horizontal high frequency auxiliary signal which is an auxiliary signal for improving image quality. On the other hand, EDTV2 system developed to improve image quality,
IDTV system, Improved PAL system, Ext
In the case of a television system signal such as an end PAL system, a horizontally long image signal having an aspect ratio of 16: 9 or the like is often a signal without a non-image portion as an image signal, and also an aid for improving the image quality. The signal exists in some form.

Therefore, a means (not shown) for identifying the type of the video signal is used to detect an identification signal indicating whether or not an auxiliary signal for improving image quality is present, and the horizontal high frequency auxiliary signal is superposed. Detect whether or not When it is confirmed that there is no horizontal high frequency auxiliary signal, the switching circuit 6 sets the switching signal C1 to 0 (enable) and C2 to 1 (disable) so as to perform subtitle processing. In this way, the processing of the horizontal high frequency auxiliary signal is unnecessary, so that the three-state bus transceiver 4 is controlled to have a high impedance, while the processing of subtitles is necessary, the three-state bus transceiver 3 has a low impedance. The output of the caption processing circuit 1 is written in the memory 5 through the three-state bus transceiver 3, and the output of the memory 5 is read by the caption processing circuit 1. By this processing, only the image part is enlarged and displayed on the display with an aspect ratio of 16: 9, and the subtitles that were in the non-image part are moved to an appropriate place in the image part and displayed, so that a large image display is realized. It will be possible and subtitles will be displayed appropriately.

Next, in the case of a signal of the EDTV2 system or the like, since the horizontal high frequency auxiliary signal is multiplexed, the switching circuit is arranged to separate the horizontal high frequency auxiliary signal by detecting the horizontal high frequency auxiliary signal. The switching signal C1 is set to 1 by 6
(Disable) and C2 to 0 (enable). By doing so, the three-state bus transceiver 3 is controlled to have a high impedance because subtitle processing is unnecessary, while the three-state bus transceiver 4 has a low impedance because horizontal high frequency auxiliary signal processing is required. The output of the horizontal high frequency auxiliary signal separation circuit 2 is written into the memory 5 through the three-state bus transceiver 4 and the output of the memory is read out to the horizontal high frequency auxiliary signal separation circuit. By this processing, the resolution in the horizontal direction, which is a feature of the EDTV2 system, is improved.

This situation is illustrated in FIG. 2 (a). Here, the input / output signal of the three-state bus transceiver 3 is a and the input / output signal of the three-state bus transceiver 4 is b. Further, when the video signal becomes difficult to see due to the switching timing, a period in which both the switching signals C1 and C2 are set to 1 (disable) may be provided as shown in (b).

An example in which the identification signal is detected as means (not shown) for identifying the type of the video signal has been described. However, a non-image portion of the video signal has a white signal or a black signal continuous for each horizontal line. It is also possible to detect whether or not it is a letter-box type signal by detecting whether or not it is present. Further, by detecting whether or not there is a character display in the non-image portion, it is possible to detect the presence or absence of the caption signal. By detecting these, it is possible to switch the memory more accurately, automatically stop the circuit system that does not need to operate, and reduce power consumption at the same time.

In the case of a video signal including an auxiliary signal for improving the image quality, the processing by the horizontal high frequency auxiliary signal separating circuit 2 is necessarily required. On the other hand, in the case of a video signal that does not include an auxiliary signal, whether or not all processing by the subtitle processing circuit 1 is necessary is not so, and there is no problem in operation, but it is a letterbox type signal that is essential. Yes, and only if subtitles are present.

Although the three-state bus transceiver is used as the switching means of the memory 5, it is needless to say that the same operation and effect can be generally obtained by using the bidirectional switching means. Further, although the switching circuit 6 is described as the control circuit of the bidirectional switch means in the embodiment, the control circuit generally has a function of controlling the bidirectional switch means according to the type of the video signal input. It goes without saying that they have the same effect.

(Embodiment 2) Next, another embodiment of the present invention will be described with reference to FIG. 3 is similar to FIG. 1, the input video signal is NTSC system, PA (not shown).
Current television systems such as L system, and EDT developed to improve the image quality of the current television system
V system, EDTV2 system, IDTV system, Improv
It is assumed that a video signal input unit capable of inputting any of various television systems such as the ed PAL system and the Extended PAL system is provided.

In FIG. 3, 1 is a caption processing circuit for moving captions, 2 is a horizontal high frequency auxiliary signal separation circuit capable of separating horizontal high frequency auxiliary signals which are multiplexed auxiliary signals for improving image quality, Reference numeral 5 is a memory, and the above is the same as in FIG. Reference numeral 7 denotes a changeover switch, which receives the output of the caption processing circuit 1 and the output of the horizontal high frequency auxiliary signal separation circuit 2,
The switching output is input to the memory 5. Reference numeral 8 is a selector switch 7 for detecting an identification signal indicating whether or not an auxiliary signal for improving image quality is present by using a means (not shown) for identifying the type of the video signal, and the horizontal high frequency auxiliary signal is superimposed. The control circuit controls based on the result of detecting whether or not

The read output of the memory 5 is connected to the input of the caption processing circuit 1 and the horizontal high frequency auxiliary signal separating circuit 2 without passing through a switch.

In this operation, the changeover switch 7 is switched in accordance with the contents of the input video signal as in the embodiment of FIG. 1, and when the caption processing circuit 1 is required, the memory 5 is used via the changeover switch 7. When the subtitle processing has been performed and the horizontal high frequency auxiliary signal separation circuit 2 is required, the auxiliary signal processing using the memory 5 is performed via the changeover switch 7. In this way, the processing adapted to the input video signal is performed, and the memory 5 can be shared.

As described above, with the current NTSC television system,
Although the EDTV2 signal which includes an auxiliary signal and is compatible with the NTSC system has been discussed to improve image quality, signal processing that requires a memory peculiar to the system exists even for an incompatible HDTV system. It goes without saying that the same effect can be obtained when the HDTV system signal is displayed by the switching process.

(Embodiment 3) An example in which one memory is switched and used for the video signal processing of the first and second video signal processing circuits will be described below.

An embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram of a circuit showing an embodiment of the present invention.

In FIG. 4, 11 is a motion detection circuit for expanding the motion signal in the time direction, 12 is a triple expansion circuit for expanding the vertical temporal resolution auxiliary signal (VT) and the vertical high frequency auxiliary signal (VH) by 3 times, Reference numeral 3 is a first three-state bus transceiver that selects an input / output signal of the motion detection circuit 11 by a switching signal C1, and reference numeral 4 is a second three-state bus transceiver that selects an input / output signal of a triple expansion circuit by a switching signal C2. Reference numeral 5 is a memory that stores either the output of the three-state bus transceiver 3 or the output of the three-state bus transceiver 4, and 13 is a switching circuit that generates switching signals C1 and C2.

The operation of the video signal processing device configured as described above will be described. First, since there is no VT or VH signal in the case of a normal NTSC system signal, the switching circuit 13 sets the switching signal C1 to 0 (enable) so as to perform the motion detection processing for extending the motion signal in the time direction.
Set C2 to 1 (disable). In this way, the three-state bus transceiver 4 becomes high impedance, the output of the motion detection circuit 11 is written in the memory 5 through the three-state bus transceiver 3, and the output of the memory 5 is read by the motion detection circuit 11. .

Next, in the case of a signal of the EDTV2 system, the switching signal C1 is set to 1 (disable) by the switching circuit 13 so that the motion signal is not expanded in the time direction so that the VT and VH signals are triple expanded. To 0 (enable). In this way, the three-state bus transceiver 3 becomes high impedance and the memory 5 has VT / V.
The output of the H signal triple expansion circuit 12 is written through the three-state bus transceiver 4, and the output of the memory is VT /
The VH signal is read out to the triple expansion circuit 12.

This situation is illustrated in FIG. 2 (a). Here, the input / output signal of the three-state bus transceiver 3 is a and the input / output signal of the three-state bus transceiver 4 is b. When the video signal becomes difficult to see due to the switching timing, as shown in (b), C1,
It suffices to provide a period in which both C2 are 1 (disable). In this embodiment, the motion detection circuit and VT / VH
Although the example in which the memory is shared with the triple expansion circuit has been shown, the motion detection circuit and the VT / VH separation circuit or the motion detection circuit and the VH expansion circuit can also be realized.

[0040]

As described above, according to the video signal processing apparatus of the present invention, for a plurality of types of video signal inputs, the characteristics of the input video signals are detected and the operation is performed according to the detection result. The amount of memory used can be reduced by selecting the video signal processing circuit system to be used. In an EDTV type image receiving apparatus using the video signal processing apparatus of the present invention, when a letterbox type signal is input, the first video signal processing circuit (for example, caption processing circuit) is selected and the video signal is selected. When processing is performed using a memory and a video signal of the EDTV2 system is input, a second video signal processing circuit (for example, a horizontal high frequency auxiliary signal separating circuit) is selected, and the same memory is used by switching the same memory. Can be processed by
It is possible to significantly reduce the cost by reducing the amount of memory.

Also, in the case of the combination example of the motion detection circuit and the VT / VH triple expansion circuit, the VT / VH separation circuit, or the VH expansion circuit, the memory amount is deleted by sharing the memory and the cost can be similarly reduced. Becomes

[Brief description of drawings]

FIG. 1 is a block diagram of a video signal processing device according to an embodiment of the present invention.

2A and 2B are waveform charts for explaining the operation of a video signal processing device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a video signal processing device according to another embodiment of the present invention.

FIG. 4 is a block diagram of a video signal processing device according to another embodiment of the present invention.

5 (a) and 5 (b) are explanatory views relating to display of a video signal on a display.

FIG. 6 is a block diagram showing an example of a conventional video signal processing device.

[Explanation of symbols]

 1 Caption processing circuit 2 Horizontal high frequency auxiliary signal separation circuit 3,4 Three-state bus transceiver 5 Memory 6,13 Switching circuit 7 Switch 11 Motion detection circuit 12 VT / VH triple expansion circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04N 7/015 H04N 7/00 A

Claims (13)

[Claims] 1. A readable / writable memory, a first video signal processing circuit for processing a video signal using the memory, and a first switching of an input / output signal of the first video signal processing circuit. A first three-state bus transceiver for selecting a signal, a second video signal processing circuit for processing a video signal using the memory, and an input / output signal of the second video signal processing circuit for a second switching signal And a control circuit that generates a first switching signal and a second switching signal, the input / output terminals of the first and second three-state bus transceivers, and the control circuit that generates the first switching signal and the second switching signal. A video signal processing device, which is connected to an input / output terminal of a memory. 2. The first video signal processing circuit is a caption processing circuit for moving captions, and the second video signal processing circuit is a horizontal high frequency auxiliary signal separation circuit for separating a horizontal high frequency auxiliary signal. 1. The video signal processing device according to 1. 3. A memory for storing a video signal, a first video signal processing circuit for processing a first video signal of the video signals using the memory, and a first video signal processing circuit. A bidirectional first switch means for connecting an input / output terminal and an input / output terminal of the memory, and a second video signal processing circuit for processing a second video signal of the video signals by using the memory. A bidirectional second switch means for connecting the input / output terminal of the second video signal processing circuit and the input / output terminal of the memory, and a control circuit for controlling the first and second switch means. A video signal processing device, comprising: the control circuit, wherein the control circuit controls interruption and conduction of the first and second switch means in accordance with a video signal. 4. A memory for storing a video signal, a first video signal processing circuit for processing a first video signal of the video signal using the memory, and a first video signal processing circuit. First connecting the output terminal and the input terminal of the memory
Switch means, a second video signal processing circuit for processing a second video signal of the video signals using the memory, an output terminal of the second video signal processing circuit and an input of the memory. The output terminal of the memory and the input terminal of the first and second video signal processing devices are provided with a second switch means for connecting terminals and a control circuit for controlling the first and second switch means. And a video signal processing device in which the control circuit controls disconnection and conduction of the first and second switch means according to a video signal. 5. The third video signal processing circuit is a caption processing circuit for moving a caption, and the second video signal processing circuit is a separation circuit for separating an auxiliary signal for improving image quality. The described video signal processing device. 6. The control circuit has a video signal discriminating means for discriminating the type of the video signal, and the video signal includes an identification signal indicating whether or not the video signal discriminating means includes an auxiliary signal for improving image quality. When it is determined that the video signal does not include the identification signal, the first switch means is turned off and the second switch means is turned on. The video signal processing device according to claim 5, wherein the video signal processing device is electrically connected and cuts off the second switch means. 7. The control circuit has a video signal discriminating means for discriminating the type of the video signal, and when the video signal discriminating means judges that the video signal includes a horizontal high frequency auxiliary signal, the first circuit is provided. When the video signal does not include a horizontal high frequency signal, the first switch means is turned on and the second switch means is turned on when the switch means is turned off and the second switch means is turned on. The video signal processing device according to claim 6, which is cut off. 8. The control circuit has a video signal discriminating means for discriminating the type of the video signal, and when the video signal discriminating means judges that the video signal includes a horizontal high frequency auxiliary signal, the first signal is detected. When it is determined that the video signal does not include the horizontal high frequency signal and includes the subtitle signal, the first switch means is turned on to perform the subtitle processing. When the circuit is driven and the second switch means is cut off, and it is determined that the video signal does not include a horizontal high frequency signal and does not include a caption signal, the first switch means is turned on to perform caption processing. 7. The video signal processing device according to claim 6, wherein the circuit is stopped and the second switch means is cut off. 9. The control circuit has a letterbox discriminating means for discriminating whether or not the video signal is a letterbox type signal having non-image portions above and below the image, and the video signal includes a horizontal high frequency auxiliary signal. If it is determined that the video signal does not include a horizontal high frequency signal and is a letterbox signal, the first switch means is shut off and the second switch means is turned on. Is the first
If the video signal does not include a horizontal high frequency signal and is not a letterbox signal, the caption processing circuit is turned on. Stop and the second
7. The video signal processing device according to claim 6, wherein the switch means is cut off. 10. The control circuit has a letterbox discriminating means for discriminating whether or not the video signal is a letterbox type signal having non-image portions above and below the image, and the video signal includes a horizontal high frequency auxiliary signal. If it is determined that the video signal is a letterbox signal, the first switch means is shut off and the second switch means is turned on, and the video signal does not include a horizontal high frequency signal, does not include a caption signal, and is a letterbox signal. When it is determined, the first switch means is turned on to drive the subtitle processing circuit and the second switch means is shut off,
When it is determined that the video signal does not include a horizontal high frequency signal and a caption signal and is a letterbox signal, and when it is determined that the video signal does not include a horizontal high frequency signal and is not a letterbox signal 7. The video signal processing device according to claim 6, wherein the subtitle processing circuit is stopped and the second switch means is cut off. 11. A memory for storing a video signal, a first video signal processing circuit for processing a first video signal of the video signals using the memory, and a first video signal processing circuit. A bidirectional first switch means for connecting an input / output terminal and an input / output terminal of the memory, and a second video signal processing circuit for processing a second video signal of the video signals by using the memory. A bidirectional second switch means for connecting an input / output terminal of the second video signal processing circuit and an input / output terminal of the memory, and a control circuit for controlling the first and second switch means. A display unit for displaying the outputs of the first and second video signal processing devices, wherein the control circuit is configured to display the first and second video signal processing devices according to a comparison result of an aspect ratio of a video signal and an aspect ratio of a screen of the display unit. ，
A video signal processing device for controlling interruption and conduction of the second switch means. 12. A memory for storing a video signal, a first video signal processing circuit for processing a first video signal of the video signals using the memory, and a first video signal processing circuit. First switch means for connecting an output terminal and an input terminal of the memory; a second video signal processing circuit for processing a second video signal of the video signals by using the memory; Second switch means for connecting the output terminal of the video signal processing circuit and the input terminal of the memory, a control circuit for controlling the first and second switch means, and the first and second video signal processing A display unit for displaying the output of the device, the output terminal of the memory is connected to the input terminals of the first and second video signal processing devices, and the control circuit displays the aspect ratio of the video signal and the display. Part of the screen A video signal processing device for controlling interruption and conduction of the first and second switch means according to a comparison result of aspect ratios. 13. The control circuit controls the first and second switch means so as to have a period in which both the first and second switch means are shut off when switching between conduction and interruption of the first and second switch means. The video signal processing device according to any one of 4, 11, and 12.