JPH01101081A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To extend the recording/reproducing time by discriminating correlations of frame or field units of an input color video signal and recording time information without recording the color video signal in case of high correlations. CONSTITUTION:One-frame components of the color video signal already inputted to a one-frame memory 3 and oneframe components of the input signal are compared with each other by a comparator 2. When correlations between the input signal and the signal in the memory are high and the difference signal is smaller than a preliminarily determined threshold value as the comparison result, frame periods of high correlations are counted to update period information. When correlations are low as the comparison result, one-frame components of the signal stored in the memory are recorded on a magnetic tape. Thus, correlations of the color video signal are used without improving the performance of a tape head system at all and a still picture of high redundancy or the like is represented by, for example, the signal of one frame to reduce the recording signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video signal recording and reproducing apparatus such as a video tape recorder (abbreviated as VTR) for recording and reproducing video signals.

2. Description of the Related Art In the VH3 system, which is one type of conventional home VTR, color video signals are recorded and reproduced in time series as one track for each field.

Problems to be Solved by the Invention In conventional VTRs, color video signals are recorded in chronological order as described above, so the recording and playback time for a certain amount of magnetic tape is fixed, and is recorded on a field-by-field or frame-by-frame basis. Even for video signals with high redundancy and correlation, the recording and reproducing time is fixed, and there is a problem that recording and reproducing for a longer period of time is not possible.

Furthermore, in order to develop a VTR capable of recording for long periods of time, it is essential to further improve the performance of tapes and heads.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is provided with a comparison circuit that determines the correlation in units of frames or fields of input color video signals, and when the correlation is large, redundant frames are removed. Alternatively, instead of recording color video signals in field units, the use efficiency of magnetic tape can be improved in terms of signal processing by providing a circuit that records and reproduces time information representing highly correlated periods together with the highly correlated color video signals. It has improved dramatically since.

Effect of the Invention With the above-described configuration, the present invention can significantly lengthen the recording and reproducing time for the same magnetic tape compared to the recording and reproducing time of the conventional color video signal recording and reproducing apparatus.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of seven parts in one embodiment of the present invention. In FIG. 1, an NTSC composite color video signal is input to an input terminal 1. Then, in the comparator 2, the color video signal for one frame that has already been input into the l frame memory 3 is compared with the input signal for one frame. As a result of this comparison, if the correlation between the input signal and the memory signal is high and the difference signal is smaller than a predetermined threshold, the video signal in the memory remains unchanged and is output to the modulator. No signals are recorded on the magnetic tape. Instead, the recording control circuit 4 counts frame periods in which the memory signal and the human input signal have a high correlation, and updates the period information. Further, as a result of the comparison, if the correlation between the memory signal and the input signal is low, the signal for one frame stored in the memory is converted from an analog signal to a digital signal by the modulator 5, and then digitally modulated. Tape head system 7 from recording amplifier 6
recorded on magnetic tape. When a color video signal for one frame is recorded on a magnetic tape in this way, the recording control circuit 4 controls the capstan so that the recording trunk has the same track pitch as the previously recorded recording trunk.・Control the motor 8. for example,
Among the signals from the nth frame signal to the (n+9)th frame, the (n)th to (n+2)th, and (n+4)th to
If the correlation of the signals of the (n+7)th frame is high, then
The signals of frames n) to (n + 2) are represented by the signals of the n-th frame, and the signals of the same ((n + 4) to (n + 4))
+7) Frame signals are represented by the (n+4)th frame signal, and as shown in FIG. 2, only frame signals without redundancy are recorded sequentially. In FIG. 2, the capstan motor 8 is controlled by the recording control circuit 4 so that the track pitch and track width for each recorded frame pair or field are constant. Furthermore, as shown in FIG.
It is recorded in 5. In the case of this embodiment, this period information is stored in the area recorded in frame units of the video signal related to the period information as shown in FIG.
Like (recorded)

Next, the operation during playback is shown.
The reproduction signal reproduced from the head system 7 reaches the digital demodulator 10 from the reproduction amplifier 9, where it is demodulated and converted back from a digital signal to an analog signal, and then reaches the memory 1) where the reproduction is controlled according to the period information also reproduced. A circuit 12 controls the capstan motor 8, holds the contents of the memory 1), and outputs the contents of the memory 1) from an output terminal 13 as a sequential NTSC composite color video signal.

In this embodiment, the color video signal is NTSC?
j [Although a combined color video signal was used, the present invention does not apply to PAL or S
It is applicable to all color video signals such as other composite color video signals such as RCAM, component color video signals, and high-definition color video signals. Furthermore, in the memory, each frame is used as one unit, but the same processing as in the embodiment can be performed even if each field or each specific number of lines is used as one unit. In addition, in the embodiment, a digital modulation method is used as a modulation method for color video signals, but even if the luminance signal is frequency modulated and the color signal is low frequency conversion amplitude modulated, as in the current home VH3 system VTR. Yes, the audio signal can be used after compressing the time axis. Also, if highly correlated video continues for a long time, the compression rate of the audio signal can be reduced by recording it at a specific period, such as every 10 frames. It's small.

Effects of the Invention In conventional VTRs, high-density recording has been achieved by shortening the wavelength of the recording signal and narrowing the track.As a result of the current progress toward shorter wavelengths and narrower tracks, tape and It is not easy to increase recording density by improving the head system.According to the present invention, redundancy can be reduced by utilizing the correlation of color video signals without any improvement in the performance of the tape head system. It is possible to reduce the number of recording signals by representing a high-quality still image with, for example, an l-frame signal. Therefore, there is a great advantage that the amount of magnetic tape used can be significantly reduced, particularly for recording and reproducing channel video signals such as animations in which still images are frequently displayed in units of several frames.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a main part in an embodiment of the present invention, and FIG. 2 is a pattern diagram showing a recording tape pattern in an embodiment of the present invention. 1...Input terminal, 2...Comparator, 3.
... Memory, 4 ... Recording control circuit, 5.
...Digital modulator, 8 ...Capstan motor, 10 ...Digital demodulator,
1)... Memory, 12... Playback control circuit, 13... Output terminal, 14... Magnetic tape, 15... First Field recording track, 16...Second field recording track, 17
...Time information.

Claims (10)

[Claims] (1) Compare the video signal stored in the memory and the input video signal, and if the difference between the two is larger than a predetermined amount, record the video signal stored in the memory on a recording medium and record the input video signal. A video signal recording and reproducing device comprising means for newly storing a signal in the memory. (2) The video signal stored in the memory is one of the video signals.
The video signal recording and reproducing apparatus according to claim 1, wherein the video signal is stored in the memory field by field. (3) The video signal stored in the memory is one of the video signals.
The video signal recording and reproducing apparatus according to claim 1, wherein each frame is stored in the memory. (4) Compare the video signal stored in the memory with the input video signal, and if the difference between the two is smaller than a predetermined amount, divide the input video signal and the video signal stored in the memory into a desired ratio. The video signal recording and reproducing apparatus according to claim 1, wherein the video signal is added to form a new video signal and the video signal is newly stored in the memory. (5) Claim No. 1, characterized in that the memory is a memory that stores video signals in the form of analog signals.
) The video signal recording and reproducing device described in item 2. (6) Claim No. 3, characterized in that the memory is a memory that stores video signals in the form of digital signals.
1) The video signal recording and reproducing device described in item 1). (7) The video signal recording and reproducing apparatus according to claim (1), wherein the video signal stored in the memory is modulated in the form of an analog signal and recorded on the recording medium. (8) The video signal recording and reproducing apparatus according to claim (1), wherein the video signal stored in the memory is modulated in the form of a digital signal and recorded on a recording medium. (9) When the video signal stored in the memory is recorded on a recording medium, the period during which the difference between the video signal recorded in the memory and the input video signal was smaller than the predetermined amount. The video signal recording and reproducing apparatus according to claim 1, characterized in that a time information signal representing the video signal is also recorded. (10) During reproduction, the video signal and the time information signal are reproduced from the recording medium, the video signal is held in the memory for a display period obtained from the time information signal, and is output from the output terminal. A video signal recording and reproducing device according to claim (9).