JPS63290477A - Recording/reproducing system for video signal - Google Patents

Abstract

PURPOSE:To attain the high quantity of a picture by distributing a video signal into plural channels, recording the signal by a rotary head that rotates at a rotary speed integer number-times standard rotary speed, reproducing the signal, and writing it in a memory to obtain the original video signal. CONSTITUTION:Video signals are written in recording-side memories 3, 4, and these video signal written in the memories 3, 4 are sequentially read with an interval of N lines, and distributed to the N+1 channels. These video signals in the N+1 channels are recorded on a tape TP by the rotary heads Ha, Hb that rotate at the rotary speed (N+1)-times standard rotary speed so that inclined tracks are formed. The inclined tracks formed on the tape TP are scanned by the said rotary heads in the rotary speed (N+1)-timed standard rotary speed to reproduce video signals in (N+1) channels, and the results are written in reproduction-side memories, and further reproduced to obtain the original video signal.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a video signal recording and reproducing method.

[Summary of the invention]

The present invention relates to a video signal recording/reproducing method, in which a video signal is written to a recording side memory, and the video signal written to the recording side memory is sequentially read every N lines.
The N+1 channel video signal is recorded on the tape so that an inclined track is formed by a rotary head that rotates at a rotational speed of N+1 times the standard rotational speed. The inclined track formed at the standard rotation speed of N+
The N+1 channel video signal is reproduced by scanning with a rotary head that rotates at 1 times the rotation speed, and the N+
By writing the video signal of one channel to the playback side memory and reading out the video signal written to the playback side memory line by line, the original video signal is obtained.
To achieve this, it is possible to realize high image quality of a playback screen, to prevent easily noticeable lines from appearing on the playback screen, and to obtain a good playback screen during variable speed playback.

[Conventional technology]

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

Therefore, in order to achieve high-quality recording and playback without sacrificing compatibility in such a VTR, the rotational speed of the rotating drum, that is, the rotational speed of the rotating head, must be adjusted to the standard rotational speed (in the case of 8 mm video). It is conceivable to record and reproduce video signals at twice the frequency (30 Hz), that is, 60 Hz.

In this case, a pair of rotating heads records the video signal on the tape so that each 1/2 field of the video signal forms one inclined track. Therefore, the video signal for one frame is recorded on the tape so that four inclined trunks are formed.

[Problems to be solved by the invention] In this way, when recording and reproducing video signals by simply increasing the rotational speed of the rotary head to twice the standard rotational speed, 1
Since the joint between the video signals of each 1/2 field of the video signal of the field is located in the center of the playback screen, the horizontal direction ij [(shown by the dashed-dotted line in Fig. 11) that is easy to see at that part. occurs, leading to deterioration in image quality. Furthermore, this 11th
The figure shows the scanning line for one field of the video signal. The solid line in the upper half is the scanning line for the video signal for 1/2 field in the first half, and the broken line in the lower half is the scanning line for the second half. Each scanning line of the video signal for 1/2 field is shown.

Further, in the case of still image playback, only the upper or lower half of the playback screen is displayed, and in the case of picture search, the position on the playback screen becomes incorrect.

In view of these points, the present invention provides recording of video signals that can achieve high image quality of the playback screen, do not generate easily visible lines on the playback screen, and can provide a good screen during variable speed playback. This is an attempt to propose a playback method.

[Means for solving problems]

The video signal recording and reproducing method according to the present invention writes the video signal to the recording side memories (3) and (4), and sequentially transfers the video signal written to the recording side memories (3) and (4) to N lines. A tilted trunk is formed on the tape TP by the rotary hoods Ha and Hb which read out the video signals at intervals and distribute them into N+1 channel video signals, and rotate the N+1 channel video signals at a rotational speed that is N+1 times the standard rotational speed. In addition to recording the tape T
The inclined trunk formed on P is rotated at a standard rotational speed of N+
The N+1 channel video signal is scanned by rotating heads Ha and Hb rotating at 1 times the rotation speed, and the N+1 channel video signal is stored in the playback side memory (
11) and (12), and the playback side memory (1
The video signals written in 1) and (12) are read line by line to obtain the original video signal.

[Effect]

According to the present invention, the video signal is stored in the recording side memory (3
), (4), and the recording side memory (3
), (4) are sequentially read out every N lines and distributed to N+1 channel video signals. A rotating head Ha that rotates the N+1 channel video signal at a rotation speed N+1 times the standard rotation speed;
Recording is performed using Hb so that an inclined track is formed on the tape TP. The inclined track formed on the tape TP is scanned by rotary heads Ha − and Hb rotating at a rotation speed N+1 times the standard rotation speed,
Play back the N+1 channel video signal, write the N+l channel video signal to the playback side memory (11), (12), and write the video signal written to the playback side memory (11), (12) line by line. Read out to obtain the original video signal.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1 shows an example of ■TR to which the present invention is applied (
FIG. 3 shows a recording system for an 8-mm video (based on a VTR with some modifications), and a reproduction system thereof.

First, the recording system will be explained. In FIG. 1, for example, a color video signal from a video camera CM is supplied to a luminance/chromaticity separation circuit (1), and a luminance signal Y and a carrier color signal C are supplied to the luminance/chromaticity separation circuit (1).
separated into The carrier color signal C is supplied to a frequency conversion circuit (2), and the carrier frequency is changed from 3.58 MHz to 7.
It is low frequency converted to 43kHz.

The luminance signal Y and the carrier chrominance signal C' after being low-frequency converted are supplied to field memories (3) and (4), respectively, and written in time series sequentially. The luminance signal Y and the low frequency-converted carrier color signal C' stored in the memories (3) and (4), respectively, are sequentially read out every other line to produce two-channel luminance signals Y1 and Y2, respectively. and low frequency converted carrier color signals C1' and C2'.

2-channel luminance signals Y1 and Y2 are FM modulator (5)
The two channels of FM modulated luminance signals Y, 7, Y2' obtained from this are supplied to the adder (
6). The two-channel low-pass converted carrier color signals C7', 02' are supplied as they are to the adder (6), and are input to the two-channel FM receiver from the FM modulator (5).
It is added to the modulated luminance signals Y1' and Y2'.

The two-channel addition output S+, S of this adder (6)
2 (31=Y1'+C1', S2=Y2
'+C2') is switched by a changeover switch SW that is switched every 1/2 field, and is supplied to the pair of rotating heads Ha and Hb, respectively.

A pair of rotating heads HaSHb is attached to one rotating drum of a tape guide drum consisting of a fixed lower drum and a rotating upper drum.
The tape (magnetic tape) TP is wound around the tape guide drum at an angle of 80 degrees. The pair of rotating healds Ha and Hb are rotated at a rotation speed twice the standard rotation speed (30 Hz), that is, 60 Hz.

Then, on the tape TP, the 2-channel addition output S+
, S2 are recorded so as to form one inclined track. FIGS. 2A and 2H show recording patterns of inclined tracks formed adjacent to each other on the tape TP. In FIG. 2A, one inclined track has the first, third, fifth, . . . No. 261
A line video signal (corresponding to the addition output S1) I is recorded, and in FIG. 2B, the second, fourth,
6th, . . . , 262nd line video signal (addition output S2
) is recorded. Then, on the following two inclined tracks, there are the 263rd, 265th, and 2nd tracks, although not shown.
67,..., video signal of the 525th line (addition output S1
) and 264th, 266th, 268th, etc.
The video signal of the 524th line (corresponding to the addition output S2) is recorded. Note that the video signals recorded on each inclined track include some overlapping portions.

Next, the reproduction system will be explained with reference to FIG. A pair of rotary heads Ha and Hb, which are the same as those in the recording system, rotate at twice the standard rotation speed as during recording, and scan the inclined tracks on the tape TP. The reproduced signals 31 and S2 (same as the addition outputs S1 and S2 in FIG. 1) from the respective inclined tracks by these pair of rotating healds Ha and Hb are switched by a changeover switch sw that is switched every 1/2 field. After the bypass filter (
7) and a low-pass filter (8).

From the bypass filter (7), two channels of FM
A modulated luminance signal Yl'Y2' is obtained, which is supplied to the FM demodulator (9) and demodulated.

Two channels of low-pass converted carrier color signals 01' and 02' are obtained from the low-pass filter (8).

Then, two-channel luminance signals Y1, Y2 from the FM detector (9) and two-channel low-pass converted carrier color signals C1', C2' from the low-pass filter (8).
are supplied to and written into the field memories (11) and (12), respectively. And memory (11), (12)
From there, the luminance signal Y and the low-frequency converted carrier color signal C' are read out for each input in chronological order. memory (
12) low-pass converted carrier color signal C' read out from
is supplied to a frequency conversion circuit (10), where the color subcarrier frequency is frequency converted from 743kHz to 3.58MHz.

Then, the luminance signal Y from the memory (11) and the carrier color signal C from the frequency conversion circuit (10) are sent to an adder (13).
By being supplied to and added to the output terminal (14)
An NTSC color video signal is output.

Fig. 4 shows the scanning lines for one field of the playback screen of the color video signal reproduced in this way, and the solid lines indicate the scanning lines of the video signal for one half field every other line. The broken lines indicate the scanning lines of the video signal corresponding to every other 1/2 field. According to this, since the video signals reproduced from different inclined tracks on the tape TP are alternately reproduced line by line, the image quality of the reproduced screen is improved and there is no possibility that hard-to-see lines will appear on the reproduced screen. .

Also, when a still image is reproduced by repeatedly scanning one inclined trunk with a rotary head, the entire screen is reproduced, although the reproduced screen becomes rough.

Furthermore, there is no possibility that the position on the playback screen will be distorted during picture search.

Other embodiments of the present invention will be described below with reference to the drawings. FIG. 5 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, with modifications added thereto), and FIG. 7 shows its playback system. Portions corresponding to those in FIGS. 1 and 3 are designated by the same reference numerals, and redundant explanation will be omitted.

First, the recording system of this VTR will be explained with reference to FIG. The color video signal from the video camera CM is supplied to a decoder (21), where the luminance signal Y and red difference signal R-
Y and blue difference signals B-Y. These luminance signals (including synchronization signals and color burst signals) Y, red difference signal RY, and blue difference signal B-Y are supplied to time compression memories (22), (23), and (24), respectively. , after time compression with a compression rate of 0.7.0.15.0.15, 0.7H with IH as a period.

The switching is performed by a changeover switch (25) which is sequentially and cyclically switched at intervals of 0.15H10 and 15H. FIG. 6 shows the waveform of the time-plex color video signal Cv output from this changeover switch (25). In FIG. 6, HD indicates a horizontal synchronizing signal and BS indicates a color burst signal.

Color video signal CV from this changeover switch (25)
are written into the field memory (26) and read out as well as the memories (3) and (4) in FIG.
After being distributed to the FM modulator (27), the signals are FM modulated. Two channels of FM converter tRi car y-video signal CV+' from this FM converter 27)
, CV2' are changeover switches SW similar to those in FIG.
rad Ha % to each pair of rotations
Hb and recorded on tape TP in the same manner as in FIG.

Next, the reproduction system will be explained with reference to FIG. A pair of rotary heads Ha and Hb, which are the same as those in the recording system, rotate at twice the standard rotation speed as during recording, and scan the inclined tracks on the tape TP. Reproduction signal CV for each inclined track from a pair of rotary heads Ha % Hb
I' and CV2' are switched by the changeover switch SW similar to that in FIG. 3, and then the FM demodulator (28)
and demodulated. The two-channel time-plex color video signals C■1 and C■2 obtained from this FM demodulator (28) are stored in the memories (11) and (1) shown in FIG.
2) and nm are written into the field memory (29) and read out line by line, and the time-plex color video signal C■ is supplied to the changeover switch (30). (31), (32), and (33) are time expansion memories that time-expand the signal by 110.7.110.15.110.15 times, respectively. Then, the changeover switch (30) operates the memory (3) with IH as the cycle.
1), (32), (33) side, 0.7H, 0, 15H
, 0, and 15H. Luminance signals Y from these memories (31), (32), (33),
The red difference signal R-Y and the blue difference signal B-Y are output from the encoder (
34) and is encoded, and the output terminal (35)
An NTSC color video signal is output.

Further embodiments of the present invention will be described below with reference to the drawings. FIG. 8 shows an example of a VTR (8
Figure 10 shows the recording system of a VTR (based on a VTR called MilliVideo, with modifications made to it), and its playback system is shown in Figures 1, 5, 3, and 7, respectively. Portions corresponding to those in the figures are designated by the same reference numerals and redundant explanation will be omitted.

First, the recording system of this VTR will be explained with reference to FIG. The color video signal from the video camera CM is supplied to a decoder (21), where the luminance signal Y and red difference signal R-
Y and blue difference signals B-Y. These luminance signals (including synchronization signals and color burst signals) Y, red difference signal RY, and blue difference signal B-Y are supplied to time compression memories (41), (42), and (43), respectively. , Hufu is time compressed with a compression ratio of 0.7.0.3.0.3. The outputs of the memories (41) and (42) are 0.7H to the memory (41) and (42) sides, respectively, with the IH period.
The changeover is performed by a changeover switch (44) which is changed over at intervals of 10 and 3H. memory (41),
The output of (43) is stored in each memory (
41) and (43) side by a changeover switch (45) which can be switched at intervals of 0.7H10 and 3H.

The output of these changeover switches (44) and (45) is 2.
Channel timeplex color video signal CV3
, CV4 waveforms are shown in FIG.

The two-channel color video signals CV3 and CV4 from these changeover switches (44) and (45) are switched by a changeover switch (46) that is switched every horizontal period (H), and then the same as in FIG. Memory (26)
is supplied to and written to.

The two-channel color video signals Cv5 and C6 read out from this memory (26) in the same manner as in FIG. 5 are supplied to the FM modulator (27) and modulated. The 2-channel FM modulated color video signal CV5', Cy, / from this FM modulator (27) is rotated at a rotation speed twice the standard rotation speed via a changeover switch SW similar to that shown in FIG. a pair of rotating heads) (a −, Hb
and recorded on the tape TP in the same manner as in FIG.

Next, the reproduction system will be explained with reference to FIG.

A pair of rotary heads Ha % Hb, which are the same as those in the recording system, rotate at twice the standard rotation speed as during recording, and scan the inclined tracks on the tape TP. Reproduction signal C for each inclined track from a pair of rotating heads Ha and Hb
V 5 ′ and CV 6 ′ are switched by a changeover switch SW similar to that shown in FIG. 3, and then demodulated by an FM demodulator (28). This FM demodulator (28)
The two-channel color video signal CVsSCV6 from the 2-channel color video signal CVsSCV6 is supplied to a memory (29) similar to that shown in FIG. 7 and written therein.

The color video signal for each line read out from the memory (29) is switched by a changeover switch (47) which is switched in one horizontal cycle (H).

(50), (51), and (52) each transmit a signal to 110.
7.110.3.110.3 This is a time expansion memory that expands time by 3 times. The color video signals CV 9 and CV 4 from the changeover switch (47) are connected to the changeover switch (47).
8) and (49).

This changeover switch (48) sets the memory (50) and (51) sides to 0. 7H, 0, 3
It can be switched with a time of H. This changeover switch (49) is connected to each memory (50) with IH as a cycle.
, (52) side with a time of 0.7H10, 3H. These memories (50), (51), (
The luminance signal Y, red difference signal R-Y, and blue difference signal B-Y from 52) are supplied to an encoder (34) and encoded, and an NTSC color video signal is output to an output terminal (35). .

In each of the above-mentioned VTRs, the case where N=1 has been described, but N can take any value such as 2, 3, 4, . . . .

Note that the present invention is also suitable for recording and reproducing EDTV television signals of double speed signals without interlace.

〔Effect of the invention〕

According to the present invention described above, it is possible to realize high image quality of the playback screen, and to record a video signal that does not cause noticeable lines on the playback screen and provides a good playback screen during variable speed playback. A playback method is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a recording system of an example of a VTR to which the present invention is applied, FIG. 2 is a recording pattern diagram of a tilted trunk, and FIG. 3 is a block diagram showing a reproduction system of an example of a VTR to which the present invention is applied. 4 is a reproduction screen diagram according to the embodiment, FIG. 5 is a block diagram showing a recording system of another example of a VTR in which the present invention is applied, FIG. 6 is a signal waveform diagram, and FIG. 7 is a diagram of the present invention. A block diagram showing a reproduction system of another example of a VTR in which the invention is applicable;
FIG. 8 is a block diagram showing a recording system of still another example of a VTR to which the present invention is applied, FIG. 9 is a signal waveform diagram, and FIG. 10 is a reproduction system of still another example of a VTR to which the present invention is applied. FIG. 11 is a block diagram showing a reproduction screen according to a conventional example. (3), (4); (26) is the recording side memory, (11
), (12); (29) is the playback side memory, Ha %
Hb is a rotating head, and TP is a tape.

Claims (1)

[Claims] At the same time as writing a video signal to a recording side memory, the video signal written to the recording side memory is sequentially read every N lines and distributed to N+1 channel video signals,
+1 channel video signal is recorded on the tape by a rotary head rotating at a rotation speed N+1 times the standard rotation speed so that an inclined track is formed on the tape, and the inclined track formed on the tape is The N+1 channel video signal is scanned by a rotary head that rotates at a rotation speed N+1 times the rotation speed, and the N+1 channel video signal is written to a playback memory, and the video written to the playback memory is A video signal recording and reproducing method characterized in that the signal is read out line by line to obtain the original video signal.