JP2508516B2 - Video signal format converter - Google Patents

Description

The present invention relates to a video signal format conversion device.

[Outline of Invention]

The present invention is a video signal format conversion device adapted to convert a first standard format component color video signal played back from a VTR into a second standard format composite color video signal, which is played back from a VTR. A reset signal having a color frame period obtained on the basis of a signal including color frame information of a first standard system component color video signal is provided in a color encoder for forming a second standard system composite color video signal. By supplying the color sub-carrier generator to the color sub-carrier generator, it is possible to obtain the second standard type composite video signal with a stable color frame with a simple circuit configuration.

[Prior Art] In a conventional high-definition video system VTR (hereinafter referred to as HD-VTR), an interlaced color video signal with 1125 scanning lines in one frame is converted into a red signal, a green signal and a high frequency luminance. Signal and green signal, using a rotating magnetic head,
Each of the red signal and the blue signal is recorded on a magnetic tape so that each one field is formed so as to form one inclined track, and the green signal + high frequency luminance signal is doubled in the time axis, and each one field is recorded. Are divided into an odd line signal and an even line signal and recorded on the magnetic tape so as to form one inclined track each.
It should be noted that these component video signals are FM-modulated and then recorded.

By the way, in such an HD-VTR, in particular, the green signal + high-frequency luminance signal which is time-doubled and divided into odd and even line signals repeats the same signal pattern every two frames. At this time, unless the two frames are edited as the minimum unit, the line signal becomes discontinuous at the editing point.

Therefore, in such HD-VTR, along with the longitudinal direction of the side edge of the magnetic tape, the control signal recorded so as to correspond to the inclined track is provided with the information of the two-frame cycle synchronized with the component video signal recorded on the tape. In order to prevent the discontinuity of the line signal from occurring at the editing point by using the information of the two-frame period obtained from this control signal during electronic editing,
It is proposed by the present applicant in Japanese Patent Application No. 56-210626.

[Problems to be solved by the invention]

By the way, if the component color video signal reproduced from the HD-VTR is converted to the composite color video signal of the NTSC system (down conversion) and then electronically edited, the component color video reproduced from the HD-VTR is used. Since there is no color frame in the signal, the color frame of the NTSC composite color video signal obtained by the format conversion becomes undefined, and if the NTSC composite color video signal obtained by this format conversion is electronically edited as it is. , The composite color video signal of the NTSC system obtained by electronic editing will not have color framing.

In view of this point, the present invention provides a VTR for a high definition video system.
A video signal format conversion device configured to convert the reproduced first component color video signal of the standard format into a composite color video signal of the second standard format with a simple circuit configuration to stabilize the color frame. The present invention intends to propose a device that can obtain the second standard type composite video signal.

[Means for solving problems]

The present invention relates to a video signal format conversion device adapted to format-convert a first standard component color video signal reproduced from a VTR of a high definition video system into a second standard composite color video signal. , VTR
2 synchronized with the first standard component color video signal reproduced from the VTR based on the reproduction signal from
A pulse generating means for generating a pulse of a frame period is provided, and a subcarrier generating means reset by a pulse from the pulse generating means is provided for a color encoder for forming a second standard type composite color video signal. This is a video signal format conversion device.

[Action]

According to the present invention, based on the reproduction signal from the VTR of the high definition video system, the first reproduction from the VTR is performed.
The sub-carrier generation means provided in the color encoder for generating the pulse of the two-frame cycle synchronized with the component color video signal of the standard system of No. 2 from the pulse generation means and forming the composite color video signal of the second standard system. , Reset by a pulse from the pulse generating means.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. In Figure 1, (1) is HD
-For VTR, as mentioned above, the number of scanning lines in one frame is 1125.
The interlaced color video signal of the book, the red signal,
It is divided into a green signal + high-frequency luminance signal and blue signal, and a rotary magnetic head is used to record one field each of the red signal and the blue signal on a magnetic tape so as to form one inclined track, and at the same time, record the green signal. + The high-frequency luminance signal is doubled on the time axis, and each field is divided into an odd line signal and an even line signal and recorded on a magnetic tape so as to form one inclined track each. There is. Further, along the longitudinal direction of the side edge of the magnetic tape, the control signal of 1/30 second period recorded corresponding to the inclined track is doubled in time axis and distributed to odd and even line signals. In addition, information of 2 frame periods (= 1/15 seconds) synchronized with the green signal + high-frequency luminance signal is provided. This is done, for example, by adding a single pulse immediately after the edge of every two frames of the control signal.

(2) is a component color video signal of the high definition video system reproduced from the HD-VTR (1)
A system conversion device (NTSC down converter) for converting the system to a composite color video signal is shown.

Next, the configuration of the method conversion device (2) will be described.
The red signal R, the green signal + high-range luminance signal G + Yh, and the blue signal B of the high-definition video system reproduced from the VTR (1) are supplied to the system conversion circuit (4), and the NTSC system red, green and blue signals R are supplied. , G, B are obtained, and this is NTSC color encoder (6)
To be supplied to.

The color encoder (6) will be described with reference to FIG. The red, green and blue signals R, G and B from the system conversion circuit (4) are supplied to the matrix circuit (10) to obtain a luminance signal Y and color difference signals I and Q. The luminance signal Y is supplied to the adder (14) as it is. The color difference signals I and Q are supplied to separate balanced modulators (11) and (12), respectively, and the phase shift circuit (1
8) The color subcarrier signals having a phase difference of 90 degrees from each other are balanced-modulated, and these are supplied to an adder (13) to be added to obtain a quadrature modulated color difference signal, that is, a carrier color signal, This is supplied to the adder (14). Then, the oscillation signal from the oscillator (16) that generates a sine wave signal having a frequency four times as high as the color subcarrier frequency F _SC is applied to a frequency divider (a quaternary counter) (17) having a division ratio of 1/4. It is supplied and divided into 1/4, and this is supplied to the phase shift circuit (18) to make a color subcarrier with a phase difference of 90 degrees, and then to the above-mentioned balanced modulators (11) and (12). Supply. Incidentally, (20) is an output terminal for the color subcarrier signal.

Further, the black burst signal from the HD-VTR (1) is supplied to the synchronizing signal generating circuit (5), where the horizontal and vertical synchronizing signals and the color burst signal are separated and supplied to the adder (14).

The adder (14) adds the luminance signal, the carrier color signal, the horizontal and vertical synchronizing signals, and the color burst signal to obtain an NTSC composite color video signal at the output terminal (7).

Therefore, in the present invention, the control signal (CTL signal) recorded on the side edge of the HD-VTR (1), for example, the magnetic tape.
To the 2-frame pulse generation circuit (3)
A pulse having a 2-frame cycle synchronized with the reproduced video signal from (1) is separated, and a cycle of 2 frames (=
A color frame reset pulse of 1 color frame) is generated, and this is supplied to the 1/4 frequency divider (17) through the input terminal (19) to reset it.

The information of the two-frame cycle may be superposed on the time code signal or the audio signal recorded on the side edge of the magnetic tape of the HD-VTR (1) along the longitudinal direction thereof.

Thus, from this system converter (2), HD-VTR
An NTSC composite color video signal having a color frame corresponding to the component color video signal of the high-definition video system, which is recorded on the magnetic tape of (1) so as to form inclined tracks, can be obtained.

The first standard system component color video signal and the second standard system composite color video signal are
Each is not limited to the above examples.

〔The invention's effect〕

According to the present invention described above, a VTR of a high definition video system is provided.
In the video signal format conversion device adapted to format-convert the reproduced component color video signal of the first standard format into the composite color video signal of the second standard format, based on the playback signal from the VTR, A pulse generating means for generating a pulse of a two-frame period synchronized with the first standard type component color video signal reproduced from the VTR is provided, and a subcarrier generating means reset by the pulse from the pulse generating means is provided. Since it was provided in the color encoder for forming the second standard system composite color video signal, a simple circuit configuration was used from the first standard system component color video signal reproduced from the VTR of the high definition video system. It is possible to obtain a second standard type composite color video signal with a stable color frame. Kill.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing the NTSC color encoder. (1) HD-VTR, (2) system conversion device, (3) two-frame pulse generation circuit, (4) system conversion circuit, (5)
Sync signal generation circuit, (6) NTSC color encoder,
(16) is an oscillator and (17) is a 1/4 frequency divider as a color subcarrier generator.

Claims (1)

(57) [Claims] Claim: What is claimed is: 1. A video signal format conversion device adapted to format-convert a first standard type component color video signal reproduced from a VTR of a high definition video system into a second standard type composite color video signal. A pulse generating means for generating a pulse of a two-frame period synchronized with the component color video signal of the first standard system reproduced from the VTR based on the reproduced signal from the VTR, and generating the pulse. A video signal format conversion device, characterized in that sub-carrier generation means reset by a pulse from said means is provided in a color encoder for forming said second standard type composite color video signal.