JPH0316396A - System converter for video signal - Google Patents

Abstract

PURPOSE:To attain changeover between a cut mode and a wide mode by switching control to a conversion memory and a signal extraction means. CONSTITUTION:The cut mode and the wide mode are provided, and write/read control to/from conversion memories 6, 7 and changeover control of selectors 13, 15, 16, 18, 19 corresponding to each mode are selected depending on the level of a switching signal to a terminal (b). Thus, the mode (cut mode) in which number of scanning lines of a MUSE system video signal is thinned to 1/2 and its picture is fitted to a pattern of the NTSC system whose aspect ratio is 4:3 by cutting off both left and right edges of the picture whose aspect ratio is 16:9, and the mode (wide mode) in which number of scanning lines of a MUSE system video signal is thinned to 1/3 and its picture is fitted to the picture of the NTSC system whose aspect ratio is 4:3 by adding a mask picture to both upper and lower edges of the picture whose aspect ratio is 16:9, are selected. Then the changeover of the cut mode and the wide mode is attained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a video signal format conversion device, and in particular, converts the MUSE format, which is a high-definition television transmission format, to the NTS format.
This relates to conversion to the C method.

(Prior technology) MUSE (Multiple Sub-Ny
The qu [stSampling Encoding) method has been proposed. Regarding this, for example, Nikkei Elec from Nikkei Maguro Hill, Inc. Therefore, in order to view high-definition Te1novision on current TV receivers, a format conversion device is required.

Conventionally developed MUSE-NTSC conversion devices take into consideration the device scale, use a filter to halve the number of scanning lines of the MUSE signal, which is easy to convert, and then delete both ends of the screen to reduce the aspect ratio to 4:3. It was. A model of this conversion method is shown in FIG. The screen in the NTSC area in FIG. 5 corresponds to the shaded part of the screen in the MUSE signal area, and the color difference signal is obtained by expanding a signal that has been compressed to 1/4.

Next, the circuit configuration of this truncated left and right end method is shown in FIG. The MUSE signal transmitted in Fig. 8 is A
It is resampled by the D converter 1. A de-emphasis circuit 2 performs de-emphasis processing during FM transmission. This de-emphasized signal is output within the field by the intra-field internal signal processing circuit 3.

The internally processed signal is transferred to a conversion memory 6 and a 1-line delay device 4.
The signal that is inputted to and further delayed by one horizontal period is inputted to the conversion memory 7, and the odd and even lines of the MUSE signal are simultaneously written to the two systems of conversion memories 6 and 7 by the memory control signal from the synchronization circuit 5. . Conversion memory 6.
7 is read out at a read sampling frequency selected to provide an aspect ratio of 4:3 for 483 effective NTSC scan lines.

The signals read out from the conversion memory 6.7 are processed separately into a luminance signal and a color difference signal.

First, the luminance signal is input to the shift circuit 8, which shifts the phase of the scanning line in the vertical direction. Note that this direction differs between odd and even fields. The output of the phase-shifting path 8 is added to the output of the conversion memory 7 by an adder 9, and then is scanned incrementally as an NTSC signal.

The color difference signals are input to expansion circuits 10 and 11 and expanded. In other words, the color difference signal is a line sequential signal compressed to 1/4, and R-Y is multiplexed on odd lines and B-Y on even lines, so writing to the conversion memory is done every even line. If the write timing pulse is controlled in this way, B-Y is read from the conversion memory 5, and R-Y is read from the conversion memory 6. 9 and 10 are expansion circuits for color difference signals compressed and multiplexed to 1/4. The Y, R-Y, B-Y signals subjected to scanning line conversion are outputted by the NTSC encoder 11 as an NTSC composite video signal or a YC separated signal of the Y signal and the carrier color signal.

(Problem to be Solved by the Invention) However, in the conventional device described above, both the left and right ends of the high-definition television signal are truncated. may enter and cause inconvenience.

The present invention has been made in view of these problems, and an object of the present invention is to provide a format conversion device that can switch from a format in which both left and right ends are truncated to a format in which the entire screen is converted by adding a simple circuit. shall be.

[Structure of the Invention] (Means for Solving the Problems) A format conversion device of the present invention according to claim 1 comprises means for resampling a MUSE format video signal, and a scanning line in which the sampling data is supplied as write data. The number and aspect ratio of the MUSE video signal to NTS
a conversion memory for converting into a C format image signal;
Signal extraction means for extracting luminance signal data and color difference signal data from data read from the conversion memory; and NT generating an NTSC video signal from the luminance signal data and color difference signal data from the signal component extraction means.
As an SC encoder and system conversion control mode, MUS
A first conversion control mode in which the number of scanning lines of the E format video signal is thinned out to 172 and both left and right ends of the screen with an aspect ratio of 16:9 are removed so that the screen can be applied to an NTSC format screen with an aspect ratio of 4:3; and a MUSE format. A second conversion control mode applies to a screen with an aspect ratio of 4:3 in the NTSC system by thinning the number of scanning lines of the video signal to 1/3 and adding mask screens to both the upper and lower ends of the screen with an aspect ratio of 16:9. and conversion control mode switching means for switching control of writing to/reading from the conversion memory and data input from the conversion memory to the signal component extraction means according to the mode.

In the format conversion device according to the present invention as set forth in claim 2, the conversion control mode switching means thins out the number of scanning lines of the MUSE format video signal to 1/2 and reduces the horizontal size of the screen with an aspect ratio of 16:9. NTS by compressing
It also has a third conversion control mode that applies to screens with an aspect ratio of 4:3 in the C format, and in addition to the first and second conversion control modes, it is also possible to switch to this third conversion control mode.

(Function) According to the present invention as set forth in claim 1, by switching the control over the conversion memory and the signal extraction means, the number of scanning lines of the MUSE video signal is thinned out to 1/2 and the aspect ratio is 16:9. The above N is removed by cutting both the left and right ends of the screen.
A mode that applies to a screen with an aspect ratio of 4 to 3 in the TSC method (hereinafter referred to as cut mode), and a mode in which the number of scanning lines of the MtJSE video signal is thinned out to 173 and a mask screen is applied to both the upper and lower ends of a screen with an aspect ratio of 16 to 9. By adding , it is possible to switch to a mode that applies to the 4:3 aspect ratio screen of the NTSC system (hereinafter referred to as wide mode), so by adding a simple circuit for that purpose, it is possible to switch between cut mode and wide mode. It is possible to switch between

Therefore, even if important information is included at both the left and right ends of the MUSE screen, no inconvenience will occur.

According to the second aspect of the present invention, the number of scanning lines of the MUSE video signal is thinned out to 1/2, and the aspect ratio is 16:9.
By compressing the horizontal size of the screen, it has a compression mode that applies to the 4:3 aspect ratio screen of the NTSC system, so it can be viewed at a 16:9 angle of view without sacrificing vertical resolution. becomes possible.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a system conversion device according to an embodiment of the present invention. The thing shown in this figure has the same components as those in FIG. 8, so the same components will be given the same reference numerals and their explanation will be omitted, and the explanation will focus on the differences. That's it.

In the ml diagram, 13 is a 1-line delay device, 14 is a line data adder, and 15 is a line data selector. 1
Line delay device 13 has MUSE from 1 line delay device 4.
Data is entered. The adder 14 is supplied with the MUSE data from the 1-line delay device 13 and the MUSE data from the field interpolation circuit 3, and the MUSE data from the field interpolation circuit 3 is supplied with the data two lines before. are added, and the average of both lines is output.

The line data selector 15 selectively outputs the MUSE data from the field interpolation circuit 3 and the MUSE data from the adder 14, and the switching is performed by a switching signal input to terminal b. When this switching signal is Lo, it is set to the terminal B side and outputs the MUSE data from the in-field push circuit 3, and when the switching signal is Hi, it is set to the terminal A side and outputs the MUSE data from the adder 14. do.

16 is a luminance signal data selector, and 17 is a luminance signal data adder. The selector 16 selectively outputs the luminance signal data from the conversion memory 6 and the luminance signal data from the transfer circuit 8. This switching of the selector 16 is also performed by a switching signal input to terminal b. When this switching signal is Lo, it is set to the terminal B side and the phase shift same path 8
The MUSE data from is output and the switching signal is Hi.
At this time, it is set to the terminal A side and the data from the conversion memory 6 is output. The adder 17 adds the data from the selector 16 and the data from the conversion memory 7 and supplies the result to 1/2 to the NTSC encoder 12 .

18 and 19 are color difference signal data selectors.

Selector 18. ．． Reference numeral 19 selectively outputs the color difference signal data from the conversion memory 6 and the color difference signal data from the conversion memory 7, and the outputs from these selectors 18 and 19 are supplied to the NTSC encoder 12.

20 is a synchronous circuit, and this synchronous circuit 20 generates write control signals and read control signals for the conversion memory 6.7 and line sequential pulses for the color difference signal data selector 18.19 based on the MUSE data from the AD converter 1. It includes a timing pulse generation circuit 21, a window pulse generation circuit 22, an AND gate 23, a line sequential pulse generation circuit 24, and a read signal generation circuit 25.

The timing pulse generation circuit 21 generates a write timing pulse for specifying a write line to the conversion memory 6.7, and here, this write timing pulse is generated in two modes. One of the modes is MUSE as shown in Figure 3(d).
This is a mode in which the data goes high for one line period for every odd line of data, and the other mode goes high for one line period for every three lines of MUSE data, as shown in FIG. 3(g).
This is the mode in which it becomes. This mode switching is performed by a switching signal input to terminal b. When this switching signal is Lo, the mode is as shown in FIG. 3(d), and when the switching signal is Hi, the mode is as shown in FIG. 3(g).

The window pulse generating circuit 22 generates a window pulse that specifies a write period in a write line, and this window pulse is also generated in two modes. One of them is a mode in which, as shown in FIG. 3(e), each of the color difference signal area and the luminance signal area in one line becomes Hi only during a period corresponding to the area excluding both the left and right ends thereof. In other words, the aspect ratio of the screen is determined to be 4:3 without distortion when the MUSE signal is converted into the NTSC signal. The other mode is a mode in which the signal is Hi for a period corresponding to the entire area where the video signal in one line exists, as shown in FIG. 3(h). The mode switching of this window pulse generation circuit 22 is also performed by a switching signal input from terminal b, and this switching signal is
When this signal is Hi, the mode is as shown in FIG. 3(e), and when the signal is Hi, the mode is as shown in FIG. 3(h).

AND gate 23 is the write timing pulse ε
An AND signal with the window pulse is generated as a write control signal. Writing of MUSE data into conversion memory 6.7 is performed according to this write control signal.

The readout signal generation circuit 25 generates a readout control signal that specifies the period for reading out the image signal from the conversion memory 6.7, and this readout control signal is also generated in two modes. One of them is shown by the shaded area in FIG. 5(b). This mode is Hi during the preimage period of the NTSC signal and Lo during the vertical synchronization signal period. The other mode is
This is the mode in which the MUSE image signal shown by the hatched area in FIG. 6(b) is converted into an NTSC signal with an aspect ratio of 16:9 and becomes HL during the image period. At this time, the period of the mask portion that occurs at the top and bottom of the screen and the vertical synchronization signal period L
It becomes o. Mode switching of the read signal generation circuit 25 is also performed by a switching signal inputted from terminal b, and when the switching signal is LO, the mode is the former mode, and when the signal is Hi, the mode is the latter mode.

The line sequential pulse generation circuit 24 is connected to the color difference signal data selector 1
Line-sequential pulses serving as 0.11 switching signals are generated in two modes. One is a mode in which the selectors 18 and 19 are fixed to the terminal/B side, and the other is a mode in which terminals B and A of the selector 18 and 19 are alternately switched for each line. This mode switching is also performed by a switching signal from terminal b, and this switching signal is L
When the signal is high, the mode is the former mode, and when the signal is Hi, the mode is the latter mode.

The device of this embodiment has the above structure, and the MUSE
A cut mode that thins out the number of scanning lines of the video signal to 1/2 and removes about 30 percent on the left and right sides of a 16:9 aspect ratio screen to apply it to an NTSC format screen with an aspect ratio of 4:3, and the MUSE method. By thinning out the number of scanning lines of the video signal to 1/3 and adding a mask screen that masks approximately 30 percentage points on the top and bottom of a screen with an aspect ratio of 16:9, a wide screen that can be applied to a screen with an NTSC format aspect ratio of 4:3 is added. It is designed to be able to switch between two format conversion modes, and its operation will be explained below.

First, when entering the cut mode, the switching signal input to terminal b is set to LO. Then, selectors 15 and 16 are set to terminal B. Further, the timing pulse generation circuit 21 generates a write timing pulse in the mode shown in FIG. 3(d), and the window pulse generation circuit 22 generates a write timing pulse in the mode shown in FIG.
Generate window pulses in mode e). Further, the read signal generation circuit 25 generates the read control ra signal in the mode shown in FIG. 5(b). Further, the output of the line sequential pulse generation circuit 24 is fixed to LO, and the selector 19 is set to B.
It will be fixed to the side.

Therefore, the MUSE data from the intra-field interpolation circuit 3 is input to the conversion memory 6 as is, and the MUSE data from the intra-field interpolation circuit 3 is input to the conversion memory 7 via the one-line delay line 4.

The write control signal becomes Hi for each odd line of the MUSE data for a period corresponding to the area excluding both the left and right ends of each of the color difference signal area and the luminance signal area in one line. Both left and right ends of even-numbered lines on the MUSE screen are discarded and only the middle part is written in the line conversion memory 7.

As a result, data within the hatched range in FIG. 5(a) is written into each memory 6, 7.

The readout from these conversion memories 6 and 7 is performed during the entire image period of the NTSC system when the readout control signal is Hi.
This is done by a clock with a frequency determined to be equal to the line.

Data from conversion memory 6 passes through phase shift path 8. This phase shift circuit 8 has a one-line delay line and an adder with variable coefficients, and adds the current input signal and the one-line delayed signal with predetermined weighting. The weighting coefficients differ between odd and even fields.

The data selector 16 outputs luminance signal data from the phase-shifted path 8 whose phase has been adjusted in the vertical direction, and this luminance signal data and the luminance signal data from the conversion memory 7 are combined into an adder 17.
An interlace scanned luminance signal in NTSC is generated.

Further, the color difference signal data from the conversion memory 6 is fixedly outputted from the selector 18, and the color difference signal data from the conversion memory 7 is outputted from the selector 19 in a fixed manner, and each is expanded by four times by the corresponding expansion circuits 10 and 11. The signal is supplied to the NTSC encoder 12. Here, as shown in FIG. 4(a), since the conversion memory 6 outputs the odd line signal of the MUSE data, the expansion circuit 10 outputs the R-Y color difference signal data, and as shown in FIG. As shown in (b), since the conversion memory 7 outputs even-numbered line signals of the MtJSE data, the expansion circuit 11 outputs BY color difference signal data.

By supplying the above signals to the NTSC encoder 12, the signal shown in FIG. 5(b) is output from the NTSC encoder 12.
A Y/C separated signal and a composite video signal are obtained which form a screen as shown in FIG.

Next, in the wide mode, the switching signal is set to Hi. Then, selectors 15 and 16 are set to the A side. Also,
The timing pulse generating circuit 21 outputs a write timing pulse as shown in FIG. 3(g), and the window pulse generating circuit 22 outputs a window pulse as shown in FIG. 3(h). Further, the line sequential pulse generation circuit 24 outputs line sequential pulses as shown in FIG. 4(e). As a result, the selectors 18 and 19 are switched line by line.

Therefore, the MUSE data from the adder 14 is input to the conversion memory 6, and the MUSE data from the in-field press circuit 3 is input to the conversion memory 7 via the one-line delay line 4.

The write control signal is applied every second line of MUSE data (
1 line period among 3 lines), a period H corresponding to the entire area where color difference signals and luminance signals exist in 1 line
i, the MUSE data of the first line and the third line among the three aQ lines are written in the conversion memory 6, and the MUSE data of the second line in the middle is written in the conversion memory 7.
E data is written. This allows conversion memory 6.
7, the data within the hatched area in Figure 5(b) in the horizontal direction is 173, which is the number of scanning lines in the MUSE method.
will be written for the number of books.

Reading from these conversion memories 6 and 7 is performed during the period shown by the hatched area in FIG. 6(h) when the read control signal is Hi, that is, when the aspect ratio is 1 on the NTSC screen.
This is done during the period when 6=9. The reading clock frequency is determined so that the reading period of one line of signals is equal to that of the NTSC system. .

The data selector 16 outputs the luminance signal data from the conversion memory 6, and this luminance signal data and the luminance signal data from the conversion memory 7 pass through an adder 17 to generate an interlace-scanned luminance signal in NTSC.

Further, color difference signal data from the conversion memory 6.7 is alternately outputted from the selectors 18.19. Here, as shown in FIG. 4(C) and FIG. 4(d), the odd line and even line signals from the conversion memories 6 and 7 are stacked alternately and mutually between both memories 6 and 7. Therefore, the selector 18 outputs R-Y color difference signal data, which is one color difference signal, and the selector 19 outputs the other B-Y color difference signal data, and the corresponding expansion times "j81011" are output.
It is expanded by 4 times.

By supplying the above luminance signal and color difference signal data to the NTSC encoder 12, the NTSC encoder 12 generates a Y-C separated signal and a composite video signal, which form a screen as shown in FIG. 6(b). will be obtained.

As described above, the format conversion device of this embodiment has a cut mode and a wide mode, and controls writing and reading to and from the conversion memories 6 and 7, as well as selectors 13, 15 . 16, 18, and 19 switching controls can be selected corresponding to each mode.

FIG. 2 is a block diagram of a system conversion device according to a second embodiment of the present invention.

In addition to the output mode and wide mode described above, the embodiment shown in this figure is characterized by thinning out the number of scanning lines of the MUSE video signal to 1/2 and compressing the horizontal size of the screen with an aspect ratio of 16:9. Therefore, it has a compression mode that is suitable for screens with an aspect ratio of 4:3 in the NTSC system, and its circuit structure is characterized by the switching control of the window pulse generation circuit 22, which is controlled by the other timing pulse generation circuit 21, line sequential pulse. It is independent from the generation circuit 24 and the read signal generation circuit 25. The switching signal is input to terminal C.

In the configuration of this embodiment, in order to enter the cut mode, the switching signal to terminal b is set to Lo, and at the same time, the switching signal to terminal C is set to LO.

Also, when setting to wide mode, conversely, terminal b,
Set the switching signal to C to H1.

When the compression mode is selected, the switching signal to terminal b is set to Lo, and the switching signal to terminal C is set to Hi.

Then, selectors 15 and 16 are set to terminal B. Further, the timing pulse generation circuit 21 generates a write timing pulse in the mode shown in FIG. 3(j) (the same mode as in FIG. 3(d)), and the window pulse generation circuit 22 generates a write timing pulse in the mode shown in FIG. 3(k) (the same mode as in FIG. 3(d)). (same mode as in Figure 3 (h))
generates a window pulse. Further, the read signal generation circuit 25 generates a read control signal shown by the hatched area in FIG. 5(b). Furthermore, line sequential pulse generation circuit 2
4 is in a state where its output is fixed to Lo and the selector 19 is fixed to the B side.

Therefore, the MUSE data from the intra-field interpolation circuit 3 is input to the conversion memory 6 as is, and the MUSE data from the intra-field interpolation circuit 3 is input to the conversion memory 7 via the one-line delay line 4.

The write control signal is Hi for each odd line of the MUSE data for a period corresponding to the entire color difference signal area and luminance signal area in one line, so the conversion memory 6 has an odd line, and the conversion memory 7 has an even line. MUSE data will be written. As a result, Figure 7 (a
), the data within the shaded range is stored in each memory 6,
7 is written.

Reading from these conversion memories 6 and 7 is performed by a clock having a frequency determined so that the reading period of one line of signals is equal to one line of the NTSC system.

Since the read control signal has a period H1 corresponding to the entire video signal period of the NTSC system, the full screen of the MUSE signal is compressed in the horizontal direction and converted into the full screen of the NTSC system.

The data selector 16 outputs luminance signal data from the phase-shifted path 8 whose phase has been adjusted in the vertical direction, and this luminance signal data and the luminance signal data from the conversion memory 7 are combined into an adder 17.
An interlace scanned luminance signal in NTSC is generated.

Further, the color difference signal data from the conversion memory 6 is fixedly outputted from the selector 18, and the color difference signal data from the conversion memory 7 is outputted from one selector in a fixed manner, and each is expanded by four times by the corresponding expansion circuits 10 and 11. , are supplied to the NTSC encoder 12. Here, as shown in FIG. 4(a), since the conversion memory 6 outputs the odd line signal of the MUSE data, the expansion circuit 10 outputs the R-Y color difference signal data, and as shown in FIG. As shown in (b), since the conversion memory 7 outputs the even-numbered line signal of the MUSE data, the expansion circuit 11 outputs BY color difference signal data.

By supplying the above signals to the NTSC encoder 12, the NTSC encoder 12 outputs the signal shown in FIG. 7(b).
A Y●C separated signal and a composite video signal are obtained, which have a screen as shown in FIG.

As described above, according to this embodiment, three types of modes can be switched by setting respective switching signals to terminals b and c.

Particularly, according to this embodiment, by providing a compression mode, a high-resolution screen with no leakage can be obtained.

In other words, in cut mode, only a portion of the MUSE signal image can be converted to an NTSC signal, and in wide mode, there are areas with no image at the top and bottom of the screen of current receivers, and the effective number of scanning lines of NTSC receivers is reduced. is reduced to about 2/3.

The compression mode solves the drawbacks of the above conversion methods, and it allows you to use all the scanning lines of the NTSC receiver.
Since the entire screen of the USE signal can be converted, there will be no missing parts of the screen at high resolution.

However, when images converted in compressed mode are viewed as they are on current TV receivers, they appear to be stretched vertically, but if the receiver is a CRT type, this can be easily countered by making the vertical deflection angle shallower. can. In the case of a projection type receiver, this problem can be solved by optically stretching the screen horizontally using a lens or the like.

In this way, 16
It can be viewed at a viewing angle of :9.

〔Effect of the invention〕

As explained above, according to the present invention as set forth in claim 1,
By switching the control over the conversion memory and signal extraction means, the number of scanning lines of the MUSE video signal is thinned out to 172, and both the left and right ends of the screen with an aspect ratio of 16:9 are removed, thereby achieving the aspect ratio of the NTSC system of 4:3.
(hereinafter referred to as cut mode), the number of scanning lines of the MUSE video signal is thinned out to 1/3, and a mask screen is added to both the top and bottom of the screen with an aspect ratio of 16:9. Since it is designed to switch between a mode that applies to screens with an aspect ratio of 4:3 (hereinafter referred to as wide mode), it is possible to switch between cut mode and wide mode by adding a simple circuit for this purpose. Become.

Therefore, no problem will occur even if important information is included at both the left and right ends of the MUSE iii surface.

According to the second aspect of the present invention, the number of scanning lines of the MUSE video signal is thinned out to 1/2, and the aspect ratio is 16:9.
By compressing the horizontal size of the screen, it has a compression mode that applies to the 4:3 aspect ratio screen of the NTSC system, so it can be viewed at a 16:9 angle of view without sacrificing vertical resolution. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the system conversion device according to the present invention as set forth in claim 1, FIG. 2 is a block diagram of an embodiment of the system conversion device according to the invention as set forth in claim 2, and FIG. The figure shows a time chart by mode of the operation related to scanning line number conversion and aspect ratio conversion of the format conversion device shown in FIG. 1 or 2 above, and FIG. 4 shows a time chart by mode of the conversion memory output of the conversion device. Figure 5 is a schematic diagram of scanning line conversion in cut mode, Figure 6 is a schematic diagram of scanning line conversion in wide mode, Figure 7 is a schematic diagram of scanning line conversion in compressed mode, and Figure 8 is a diagram of conventional format conversion. FIG. 2 is a block diagram of the device. 1... AD converter, 2... De-emphasis circuit,
3... Field interpolation circuit, 4.13... 1 line delay line, 6.7... Conversion memory, 8... Phase shift circuit, 10.11... Expansion circuit, 12...・NTSC encoder, 14.17... Adder, 15, 16.18.
19... Selector, 20... Synchronous circuit, 21...
Timing pulse generation circuit, 22... Window pulse generation circuit, 23... AND gate, 24... Line sequential pulse generation circuit.

Claims (1)

[Claims] 1. A format conversion device for converting a MUSE video signal into an NTSC video signal, which converts the number of scanning lines and aspect ratio of the MUSE video signal into the number of scanning lines and aspect ratio of the NTSC video signal. a system converter that converts the video signal into a video signal, an NTSC encoder that generates the output video signal of the system converter as the NTSC video signal, and the MUSE
A first conversion mode in which the number of scanning lines of the system video signal is thinned out to 1/2 and both left and right ends of the screen with an aspect ratio of 16:9 are removed to apply the screen to the screen with an aspect ratio of 4:3 in the NTSC system; By thinning the number of scanning lines of the MUSE video signal to 1/3 and adding mask screens to both the top and bottom ends of the screen with an aspect ratio of 16:9, the above NTS
a conversion control unit having a second conversion mode applied to a screen with an aspect ratio of 4:3 in the C format, and controlling operations of the scanning line number conversion unit and the aspect ratio conversion unit according to the mode; A video signal format conversion device, comprising: a mode specifying section that specifies the format conversion control mode to a control section; 2. A format conversion device for converting a MUSE video signal into an NTSC video signal, comprising: a scanning line number conversion unit that converts the number of scanning lines of the MUSE video signal to the number of scanning lines of the NTSC video signal; an aspect ratio converter that converts the output video signal of the scanning line number converter into a video signal having an aspect ratio of the NTSC system;
an NTSC encoder that generates a video signal; and a system conversion control mode that thins out the number of scanning lines of the USE video signal to 1/2 and compresses the horizontal size of a screen with an aspect ratio of 16:9. A video signal system having a compression mode applied to a screen with an aspect ratio of 4:3, and comprising conversion control means for controlling the operations of the scanning line number converter and the aspect ratio converter according to the mode. conversion device.