JP2569558B2 - Recording and playback method of color video signal - Google Patents

Description

The present invention relates to a method for recording and reproducing a color video signal.

[Conventional technology]

VTR called 8mm video has a drum diameter of 40mm
Therefore, it is difficult to improve recording and reproduction to high image quality with the same configuration.

Therefore, in such a VTR, in order to realize high-quality recording / reproduction without compromising compatibility, the rotation speed of the rotating drum, that is, the rotation speed of the rotating head, must be adjusted to the standard rotation speed (for 8 mm video, For example, it is conceivable to record and reproduce the video signal at twice the frequency of 30 Hz, for example, 60 Hz.

In this case, the video signal is recorded on the tape by a pair of rotary heads such that each half field forms one inclined track. Therefore, the video signal for one frame is recorded so that four inclined tracks are formed on the tape.

[Problems to be solved by the invention]

As described above, when recording and reproducing a video signal by simply setting the rotation speed of the rotary head to twice the standard rotation speed,
Since the joint between the video signals of each half field of the video signal of one field is located at the center of the playback screen, a horizontal line (shown by a one-dot chain line in FIG. ) Occurs, which leads to poor image quality. This FIG. 11
The scanning line for one field of the video signal is shown, the solid line in the upper half is the scanning line of the video signal for the first half field, and the broken line in the lower half is the video for the latter half field. The signal scanning lines are shown.

Further, in the case of still image reproduction, the reproduction screen is only the upper or lower half, and in the case of picture search, the position on the reproduction screen is out of order.

In view of this point, the present invention can realize high image quality of a reproduction screen, and does not generate an easily visible line on the reproduction screen, and furthermore, a color video signal which can obtain a good screen at the time of variable speed reproduction. It is intended to propose a recording / reproducing method.

[Means for solving the problem]

The method of recording and reproducing a color video signal according to the present invention comprises the steps of:
, And a line signal formed by time-compressing each of the color signals, a luminance signal including a synchronization signal and a color burst signal, and a line signal formed by time-compressing each of the second color signals. The color video signal is written to the recording-side memory, and the color video signal written to the recording-side memory is sequentially read out every other line and divided into two-channel color video signals.
The two-channel color video signal is recorded by a rotating head rotating at twice the standard rotation speed so that an inclined track is formed on the tape, and the inclined track formed on the tape is recorded on the tape. A 2-channel color video signal is reproduced by scanning with a rotating head that rotates at a rotation speed twice the standard forward rotation speed, and the 2-channel color video signal is written to a reproduction side memory and written to the reproduction side memory. The original color video signal is obtained by reading the obtained color video signal line by line.

[Action]

According to the present invention, the luminance signal including the synchronization signal and the color burst signal, and the line signal formed by time-compressing the first color signal, the luminance signal including the synchronization signal and the color burst signal, and the second signal A color video signal consisting of a line-sequential signal with a line signal formed by time-compressing each color signal is written to a recording-side memory, and the color video signal written to the recording-side memory is sequentially placed every other line. The readout video signal is read and divided into two-channel color video signals, and the two-channel color video signals are recorded by a rotating head rotating at a rotation speed twice the standard rotation speed so that an inclined track is formed on the tape.

Then, the inclined track formed on the tape is scanned by a rotating head rotating at a rotation speed twice as high as the standard forward rotation speed to reproduce a two-channel color video signal. The original color video signal is obtained by writing in the reproduction side memory and reading out the color video signal written in the reproduction side memory line by line.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a recording system of an example of a VTR to which the present invention is applied (based on a VTR called 8 mm video and modified), and FIG. 3 shows a reproducing system thereof.

First, the recording system of this VTR will be described with reference to FIG. The color video signal from the video camera CM is supplied to a decoder (21) and is separated into a luminance signal Y, a red difference signal RY, and a blue difference signal BY. These luminance signals (including a synchronization signal and a color burst signal) Y and a red color difference signal RY
And the blue difference signal BY are time compression memory (41),
The data is supplied to (42) and (43) and time-compressed at a compression ratio of 0.7, 0.3, and 0.3 respectively. The outputs of the memories (41) and (42) are switched to the memories (41) and (42) by a changeover switch (44) which is switched to the memories (41) and (42) at intervals of 0.7H and 0.3H, respectively, with a period of 1H. Memory (41),
The output of (43) has a cycle of 1H, and the memory (41),
It is switched to the (43) side by a changeover switch (45) that can be switched over in 0.7H and 0.3H intervals.

FIG. 2 shows the waveforms of the two-channel time-plex color video signals CV ₃ and CV ₄ output from the changeover switches (44) and (45). These changeover switches (44),
2-channel color video signals CV ₃ and CV from (45)
₄ is switched by a changeover switch (46) which is switched every one horizontal cycle (H), and then supplied to a field memory (26) to be written. From the memory (26), 2-channel color video signal CV ₅ for read, C
V ₆ is supplied to an FM modulator (27) and modulated. The two-channel FM modulated color video signals CV ₅ ′ and CV ₆ ′ from the FM modulator (27) are rotated via a changeover switch SW at a rotation speed that is twice the standard rotation speed. It is supplied to Ha and Hb and recorded on the tape TP.

A pair of rotary heads Ha and Hb are mounted on a rotary drum of a tape guiding drum comprising a fixed lower drum and a rotary upper drum,
The tape (magnetic tape) TP is wound around the tape guide drum at a winding angle of 180 °. The pair of rotating heads Ha and Hb are:
It is rotated at twice the rotation speed of the standard rotation speed (30 Hz), that is, at 60 Hz.

Then, on the tape TP, as shown in FIG. 4A, the first, third, fifth,..., 261st line (the luminance signal including the synchronization signal and the color burst signal, respectively) In addition, an FM-modulated color video signal CV ₅ ′ of a half-field color video signal CV ₅ composed of a line signal formed by time-compressing a red difference signal is recorded. As shown in FIG. 4B, the second, fourth, sixth,..., 262nd lines (the luminance signal including the synchronizing signal and the color burst signal and the blue difference signal respectively) Of the color video signal CV ₆ for 1/2 field composed of time-compressed line signals).
The FM modulated color video signal CV ₆ ′ is recorded. The other two inclined tracks following these two inclined tracks have 283, 265, 267,.
-, # 525 the FM modulated color video signal CV ₅ 1/2 field of consisting of (respectively synchronizing signal and a luminance signal and line signal is configured red color difference signal is compressed respectively time including color burst signal) line Color video signal CV ₅ '
524, 264, 266, 268,..., 524th line (a line signal formed by time-compressing a luminance signal including a synchronization signal and a color burst signal and a blue difference signal, respectively) Of the color video signal CV ₆
The FM modulated color video signal CV ₆ ′ is recorded. Thus,
The FM modulated signal of the color video signal for one frame is recorded on a tape so as to form four inclined tracks. Note that the color video signal recorded on each inclined track actually includes a part of an overlap portion.

Next, the reproducing system will be described with reference to FIG.
A pair of rotary heads Ha and Hb, which are the same as the recording system, rotate at a rotation speed twice as high as the standard rotation speed as in the case of recording.
Scan the inclined track on TP. A pair of rotating heads Ha,
The reproduced signals CV ₅ ′ and CV ₆ ′ for each inclined track from Hb are
Changeover switch SW that can be switched every half field
, And demodulated by the FM demodulator (28). The two-channel color video signals CV ₅ and CV ₆ from the FM demodulator (28) are supplied to the field memory (29) and written therein. The color video signal for each line read from the memory (29) is switched by a switch (47) which is switched every horizontal cycle (H).

(50), (51), and (52) use 1 / 0.7 and 1/0.
3. This is a memory for time expansion that expands the time by a factor of 1 / 0.3. The color video signals CV ₃ and CV ₄ from the changeover switch (47)
It is supplied to the changeover switches (48) and (49). The changeover switch (48) has a cycle of 1H, and each memory (5
0) and (51) can be switched with 0.7H and 0.3H respectively. The changeover switch (49) is switched to the memories (50) and (52) with a period of 1H at intervals of 0.7H and 0.3H, respectively. These memories (50), (5
The luminance signal Y, red color difference signal RY, and blue color difference signal BY from 1) and (52) are supplied to an encoder (34) and encoded, and an NTSC color video signal is output to an output terminal (35). .

FIG. 5 shows the scanning lines for one field of the reproduced screen of the color video signal reproduced in this manner, and the solid line indicates 1 line.
A scanning line of a color video signal for 1/2 field of every other line is shown.
3 shows scanning lines of a color video signal for a field. According to this, since the color video signals reproduced from the different inclined tracks on the tape TP are alternately reproduced for each line, the image quality of the reproduction screen is improved, and there is a possibility that an invisible line is reported on the reproduction screen. Absent.

Also, when a still image is reproduced and one inclined track is repeatedly scanned and reproduced by the rotary head, the reproduced screen becomes coarse, but the entire screen is reproduced.

Further, at the time of picture search, there is no possibility that the position on the reproduction screen is out of order.

Further, the video signal to be written to the recording side memory and the reproduction side memory is a line signal formed by time-compressing a luminance signal including a synchronization signal and a color burst signal and a red difference signal, respectively, and a synchronization signal and a color burst signal. Since the included luminance signal and the blue difference signal are color video signals composed of line-sequential signals with time-compressed line signals, it is easy to determine the color difference signal during variable speed reproduction.

It should be noted that the present invention is also suitable for recording / reproducing a double-speed signal without interlace of an EDTV television signal.

〔The invention's effect〕

According to the present invention described above, the luminance signal including the synchronization signal and the color burst signal, and the line signal formed by time-compressing the first color signal, the luminance signal including the synchronization signal and the color burst signal, and the second signal A color video signal composed of a line-sequential signal with a line signal formed by time-compressing the color signals of the respective colors is written into a memory on the recording side, and the color video signal written on the memory on the recording side is sequentially placed every other line. And distributes the two-channel color video signal to the tape so that an inclined track is formed on the tape by a rotary head that rotates at a rotation speed twice the standard rotation speed. And rotating the inclined track formed on the tape at a rotation speed twice the standard forward rotation speed. A two-channel color video signal is reproduced by scanning with a read-out memory, the two-channel color video signal is written to a reproduction-side memory, and the color video signal written to the reproduction-side memory is read out line by line, Color video signal, it is possible to improve the quality of the reproduced color screen, and to make the reproduced color screen less prominent. Also, when one inclined track is repeatedly scanned and reproduced by the rotating head, the reproduced screen is coarse, but the entire screen is reproduced, and there is no possibility that the position on the reproduced screen is deviated at the time of the picture search. A signal recording / reproducing method is obtained.

Further, the video signal to be written to the recording side memory is
A line signal formed by time-compressing the luminance signal including the synchronization signal and the color burst signal and the first color signal, and the luminance signal and the second color signal including the synchronization signal and the color burst signal are respectively time-compressed. Is a color video signal consisting of a line-sequential signal with a line signal composed of a half-field color video signal consisting of a line signal containing only the first color signal of the two types of color signals. Of the two types of color signals, the color video signals for a half field consisting of line signals containing only the second color signal are alternately recorded on the tape so as to form inclined tracks. It is easy to determine the color signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a recording system as an example of a VTR to which the present invention is applied, FIG. 2 is a signal waveform diagram, FIG. 3 is a block diagram showing a reproducing system as an example of a VTR to which the present invention is applied, FIG. 4 is a recording pattern diagram of an inclined track, FIG. 5 is a schematic diagram showing a reproduction screen according to the embodiment, and FIG. 6 is a schematic diagram showing a reproduction screen according to a conventional example. (26) is recording side memory, (29) is reproduction side memory, Ha, Hb
Is a rotary head and TP is a tape.

Claims (1)

(57) [Claims] 1. A luminance signal including a synchronization signal and a color burst signal, and a line signal formed by time-compressing a first color signal, a luminance signal including a synchronization signal and a color burst signal, and a second color signal. Write a color video signal consisting of a line-sequential signal with a line signal that is time-compressed, respectively, to a recording side memory, and sequentially write the color video signals written to the recording side memory by 1
It is read out every other line and divided into two-channel color video signals, and the two-channel color video signals are rotated by a rotating head rotating at twice the standard rotation speed so that an inclined track is formed on the tape. While recording, the inclined track formed on the tape is scanned by a rotating head rotating at a rotation speed twice as high as the standard forward rotation speed to reproduce the two-channel color video signal.
The two-channel color video signal is written to a reproduction side memory, and the color video signal written in the reproduction side memory is read out line by line to obtain an original color video signal. Recording and playback method.