JPH0263281A - Video recording circuit for plural channels - Google Patents

Abstract

PURPOSE:To successively record video signal on plural channels on one and same signal recording medium while they are synchronized with each other by controlling the recording operation of a 1st video signal synchronously with the video signal while reproducing a 2nd video signal recorded already on the signal recording medium with time axis compression. CONSTITUTION:The 2nd video signal is recorded on a prescribed track part of each signal track of a signal recording medium while being subject to time axis compression in the horizontal scanning direction (or vertical direction), a recording and reproducing head 13 is connected to a signal reproducing means for a period when the recording and reproducing head 13 scans a prescribed track part during each horizontal scanning period (or each field period), that is, for the 2nd split period, and a reproducing circuit 15 reproduces the recording signal. A control circuit 6 generates a readout control signal synchronously with the vertical and horizontal synchronizing signals included in, e.g., the video signal based on the compressed 2nd video signal from the reproducing circuit 15 and supplies it to a memory 4. Thus, the compressed 1st video signal is recorded in each 1st split period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording circuit that can time-divisionally record video signals of multiple channels onto the same signal recording medium.

(Prior art) A two-channel simultaneous video transmission device as shown in FIG.
04N7/16] ). In this device, a control circuit (
30), the two-channel video signal V2,
■2 is written to the memory (27) (28) via the A/D converter (25) (26), respectively, and at the same time, the memory (27) (28) is written at twice the writing speed.
8) is read out. As a result, the time axis of both video signals is compressed to 1/2 in the horizontal scanning direction. Both compressed video signals are distributed to the left and right sides of one horizontal scanning line via a changeover switch (29), and the resulting composite video signal passes through a D/A converter (31) and then is sent to one transmission line. It is transmitted by

(Problem to be Solved) If the above two-channel video simultaneous transmission device is applied to, for example, a video tape recorder, it is convenient to be able to simultaneously record video signals for two channels on the same magnetic tape.

However, in this case, it is necessary to record two channels of video signals on the magnetic tape at the same time. First, only one video signal is recorded on the magnetic tape by one side of the circuit shown in FIG. 12, and then the other channel is recorded on the magnetic tape. Video signals cannot be recorded on the same magnetic tape.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multi-channel recording circuit that can sequentially record video signals of multiple channels on the same signal recording medium at different times. It is an object of the present invention to provide a recording method that can control the recording operation of a video signal by referring to the video signal while reproducing the compressed and recorded video signal.

(Means for Solving the Problems) A multi-channel recording circuit according to the present invention connects a signal recording means and a signal reproducing means to a recording/reproducing head (13) via a switching circuit (12).

The switching circuit (12) switches one horizontal scanning period (or one field period) to the signal recording means side during the first divided period in each horizontal scanning period (or within each field period) and to the signal reproducing means side during the second divided period.
It is switched at a cycle of (field period).

The signal recording means includes a memory (4) in which a first video signal to be recorded on a signal recording medium is written at a predetermined period, and a memory (4) for recording the first video signal from the memo IJ-(4) in a horizontal scanning direction (or vertical direction). Control circuit that compresses the time axis and reads it out (6)
It is equipped with.

Further, the signal reproducing means provides each signal track with a horizontal scanning direction (
It is equipped with a reproduction circuit (15) for reproducing the second video signal recorded with time axis compression in the vertical scanning direction), and the output end of the reproduction circuit is connected to the control circuit (6). .

The control circuit (6) controls for reading the compressed first video signal from the memory (4) within each of the first divided periods based on the compressed second video signal reproduced in each of the second divided periods. It creates a signal and supplies it to Memo IJ-(4).

(Function) In each signal track of the signal recording medium, the second video signal is recorded in a predetermined track portion with time axis compression in the horizontal scanning direction (or vertical direction), and during each horizontal scanning period ( or during each field period), and during the period in which the recording/reproducing head (13) scans the predetermined track portion, that is, in the second divided period, the recording/reproducing head (13) is connected to the signal reproducing means, and the reproducing circuit (15) is connected to the signal reproducing means. ), the recorded signal is reproduced.

The control circuit (6) creates, for example, a readout control signal synchronized with vertical and horizontal synchronization signals included in the video signal based on the compressed second video signal from the playback circuit (15), and sends it to the memory (4). supply

As a result, during each horizontal scanning period (or during each field period), the memory (4 ), the first video signal is time-axis compressed and read out.

The read compressed first video signal is sent to the switching circuit (12)
The signal is then sent to the recording/reproducing head (13) and recorded on a signal recording medium.

(Effects of the Invention) According to the multi-channel recording circuit according to the present invention, as described above, while reproducing the second video signal that has already been time-axis compressed and recorded on the signal recording medium, it is possible to synchronize with the video signal. hand,
Since the recording operation of the first video signal can be controlled, video signals of a plurality of channels can be sequentially recorded on the same signal recording medium in a mutually synchronized state.

(Embodiment) Figure 1 shows a first embodiment in which a multi-channel recording circuit according to the present invention is implemented in a video tape recorder. is time-compressed in the horizontal scanning direction and recorded on each signal track of the magnetic tape.

As shown in FIG. 4, each signal track (33) of the magnetic tape (32) is constituted by alternately providing track portions A and B, and a pair of adjacent track portions A and B corresponds to one horizontal scanning line. The video signal is composed of: As described later, in each track section A, the video signal of the first channel (first video signal) is compressed to 1/2 on the time axis and recorded.
In each track portion B, the video signal of the second channel (second video signal) is compressed in time axis to 1/2 and recorded.

First, the circuit configuration of the present invention will be explained for the case where the first video signal is compressed and recorded on each track section A on a magnetic tape on which the second video signal has already been recorded on each track section B, and then The method of recording the video signal will be described later.

As shown in FIG.
The video signal ■ is connected to a Y/C separation circuit (1), where it is separated into a luminance signal Y and a chroma signal C, and the chroma signal C is further processed by a decoder (2) into a pair of color difference signals R-
Y and B-Y.

The luminance signal and color difference signal are converted into digital signals by an A/D converter (3), and then sent to a memory (4) capable of storing, for example, one frame's worth of video signals.

The output terminal of the write control circuit (5) is connected to the write control terminal of the memory (4). The write control circuit (
5) is for creating a write control signal including a horizontal drive pulse and a vertical drive pulse based on the first video signal V, and is constituted by a well-known AFC circuit or the like.

Further, the output terminal of the read control circuit (6) is connected to the read control terminal of the memory (4). The continuous output control circuit (6) generates a readout control signal D2 including horizontal and vertical drive pulses based on a reproduced luminance signal Y', which will be described later, and is constituted by an AFC circuit or the like as described above.

Memory (4) under the control of the write control circuit (5)
The video signal written in is read out at twice the writing speed under the control of the readout control circuit (6) at a timing described later. As a result, the video signal is time-axis compressed to 1/2 in the horizontal scanning direction.

A D/A converter (7) converts a luminance signal Y and a pair of color difference signals R-YS from the compressed video signal obtained from the memory (4).
B-Y is generated, and the same color difference signal is sent to the encoder (8).

A color synchronization control circuit (9) is connected to the control terminal of the encoder (8).
The output end of is connected. The color synchronization control circuit (9) is
It creates a control signal F including a color subcarrier based on a reproduced chroma signal C', which will be described later, and is constituted by a well-known APC circuit, a color subcarrier generation circuit, and the like. As a result, the pair of color difference signals are converted into a chroma signal C.

The first video signal V time-axis compressed by the above processing includes a luminance signal Y and a chroma signal compressed in the first half of one horizontal scanning period (IH), as schematically shown in FIG. 3(V). It includes a signal C, a horizontal synchronization signal H3 and a color burst BS in accordance with a normal signal format.

The luminance signal Y and the chroma signal C are sent to the recording signal processing circuit (10) as shown in FIG. (12).

The switching circuit (12) is switched at a cycle of one horizontal scanning period by a switching control pulse P to be described later, and a recording/reproducing head (13) is connected to a common terminal C.
A recording amplifier circuit (11) is connected to one switching terminal a, and a reproduction amplifier circuit (14) is connected to the other switching terminal a.

The switching control pulse P indicates that the recording/reproducing head (13)
During the period when the track portion A shown in the figure is scanned, that is, during the first division period, the signal becomes H'' as shown in FIG. 3(P), and the switching circuit (12) is switched to the terminal a side.

As a result, the time-compressed first video signal (2) is recorded on the track section.

Further, the control pulse P is "L" during the period when the recording/reproducing head (13) scans the track portion B, that is, during the second division period, and switches the switching circuit (12) to the b side, thereby causing the track section B to be scanned. B signal reproduction is performed.

Note that the control pulse P can be easily created using, for example, the horizontal synchronization signal included in the first video signal as a phase reference.

When the switching circuit (12) is conductive to the terminal, the compressed second video signal obtained from the regenerative amplifier circuit (14) has the following:
As schematically shown in FIG. 3 (V'), one horizontal scanning period (
It includes a luminance signal Y' and a chroma signal C' compressed in the latter half period of IH), a horizontal synchronizing signal H3' and a color burst BS' in accordance with a normal signal format.

The output end of the regenerative amplifier circuit (14) is connected to the luminance system regenerative circuit (15).
) and a chroma system reproduction circuit (16), thereby producing a reproduced luminance signal Y' and a reproduced chroma signal C'. The reproduced luminance signal Y' is sent to the readout control circuit (6), and the reproduced chroma signal C' is sent to the color synchronization control circuit (9).
).

The readout control circuit (6) and the color synchronization control circuit (9) are the third
The operation is performed based on the second video signal shown in FIG. 5(V'), and as a result, the first video signal shown in FIG. 12(V) is read out at the timing shown.

Therefore, by switching the switching circuit at the timing shown in FIG. 3(P), the first video signal is recorded on the track portion A of the magnetic tape in synchronization with the second video signal.

In FIGS. 5(a) to (g), the first image to be newly recorded on the magnetic tape is shown in FIG. 5(a), and the second image already recorded on the magnetic tape is shown in FIG. 5(b). In this case, the effects achieved by the above circuit will be explained. Incidentally, the second image is compressed to 1/2 and recorded as shown in FIG. 3(d).

The time axis of the first image is compressed to 1/2 by writing to and reading from the memory as shown in FIG. It is joined with the second image.

The first and second video signals recorded on the magnetic tape are selectively reproduced by a reproduction circuit, which will be described later, so that a signal corresponding to one of the images is reproduced as shown in FIG. 5(f) or (g). is enlarged and displayed on the screen of the television receiver.

FIG. 2 shows a circuit for selectively enlarging and reproducing one of the images.

The chroma signal C' outputted from the chroma system reproduction circuit (16) is processed by a decoder (17) into a pair of color difference signals RY,
, B-Y, and these color difference signals and the luminance signal Y' output from the luminance system reproduction circuit (15) are converted to A/D.
It is written to the memory (19) via the converter (18).

A write/read control circuit (20) that controls the operation of the memory (19) is connected to the luminance signal Y' and a command signal S for selecting which image shown in FIG. 5(e). . As a result, the video signal corresponding to the first or second image is read out from the memory (19) at half the writing speed, and the video signal expanded twice in the horizontal scanning direction is thereby It is sent to the D/A converter (21).

a color synchronization control circuit (23) to which the luminance signal Y'' obtained from the D/A converter (21) and the chroma signal C' are connected;
The chroma signal C' obtained through the encoder (22) is mixed with the Y/C mixing circuit (24) under the control of the Y/C mixing circuit (24), and then supplied to the television receiver. As a result,
The selected image is enlarged to its original size and displayed as shown in FIG. 5(f) or (g).

Note that the write/read control circuit (20) and color synchronization control circuit (23) in FIG. 2 are the same as the read control circuit (6) in FIG.
) and color synchronization control circuit (9).

Next, a circuit configuration for time-compressing and recording the second video signal on a non-recording magnetic tape will be described.

The circuit can be configured as follows using, for example, the circuit configuration shown in FIG. That is, in the circuit shown in FIG. 1, the luminance system reproduction circuit (15) and the chroma system reproduction circuit (16)
) and also stops the operation of the write control circuit (5).
A second video signal to be recorded is connected to the readout control circuit (6). The encoder (8) also includes a decoder (
2) supplying the color subcarrier obtained from 2) as a control signal,
The switching circuit (12) is set on the terminal a side. As a result, the time axis of the second video signal is compressed to 1/2, sent to the recording/reproducing head (13), and recorded on track section B of the magnetic tape.

Of course, various modifications can be made to the above device within the technical scope of the claims.

For example, when recording a third channel's video signal with three times the time axis compressed on a magnetic tape on which two channels' worth of video signals are each recorded with three times the time axis compressed, The present invention is effective. In this case, while reproducing the already recorded video signal of the first channel, the compressed video signal of the third channel can be supplied to the magnetic head while the magnetic head scans the empty track portion of each signal track. good.

1. This embodiment relates to a recording circuit for compressing the time axis of two channels of video signals in the vertical scanning direction and recording them on a magnetic tape.

The configuration of the recording circuit of this embodiment is exactly the same as the circuit of FIG. 1 of the first embodiment, and the only difference is the time axis compression operation as will be described later, so a description of the circuit configuration will be omitted.

As shown in FIG. 7, each signal track (33) of the magnetic tape (32) is divided into two parts, track part A and track part B. As will be described later, track part A contains the video signal of the first channel (the first The video signal of the second channel (second video signal) is compressed to 1/2 in the vertical scanning direction and recorded on the track section B.
The time axis will be compressed and recorded in 2.

In the circuit shown in FIG. 1, the operation that is different from the first embodiment is that when the video signal written in the memory (4) is read out by the operation of the readout control circuit (6), 1
The reading speed in units of horizontal scanning line signals is twice the writing speed. As a result, the first video signal V is vertically time-compressed by 172 times.

The time-axis compressed first video signal V sent to the recording signal processing circuit (10) includes a first video signal V compressed in the first half of one field period (IV), as schematically shown in FIG. 6(V). It includes a luminance signal Y, a chroma signal C, and a vertical synchronization signal vS in accordance with a normal signal format.

Further, in this embodiment, the switching circuit (12) shown in FIG. 1 is switched at a cycle of one field period by a switching control pulse P, which will be described later.

The switching control pulse P indicates that the recording/reproducing head (13)
During the scanning period of the track portion A shown in the figure, that is, during the first division period, the signal becomes "H" as shown in FIG. 6(P), and the switching circuit (12) is switched to the terminal a side.

As a result, the time-compressed first video signal V is recorded on the track section A.

In addition, the control pulse P is set as shown in FIG.
As shown in P), it becomes "L" and switches the switching circuit (12) to the b side, thereby reproducing the signal of track B.

Note that the control pulse P can be easily created using, for example, a head switching pulse or the like as a phase reference.

When the switching circuit (12) is conductive to the terminal, the compressed second video signal obtained from the regenerative amplifier circuit (14) has the following:
As schematically shown in FIG. 6 (V'), the luminance signal Y' and chroma signal C' compressed in the second half of one field period (IV), and the vertical synchronization signal in accordance with the normal signal format. ■ Contains S' etc.

Therefore, by switching the switching circuit at the timing shown in FIG. 6(P), the first video signal is recorded on the track portion A of the magnetic tape in synchronization with the second video signal.

8(a) to (g), the first image to be newly recorded on the magnetic tape is shown in FIG. 8(a), and the second image already recorded on the magnetic tape is shown in FIG. 8(b). In this case, the effects achieved by the above circuit will be explained. Incidentally, the second image is compressed to 1/2 and recorded as shown in FIG. 3(d).

The time axis of the first image is compressed to 1/2 by writing to and reading from the memory as shown in FIG. It is joined with the second image.

The first and second video signals recorded on the magnetic tape are selectively reproduced by a reproduction circuit, which will be described later, so that a signal corresponding to one of the images is reproduced as shown in FIG. 8(f) or (g). is enlarged and displayed on the screen of the television receiver.

The circuit for selectively enlarging and reproducing one of the images is also
Although it has the same configuration as the circuit shown in FIG. 2 in the above embodiment,
In this embodiment, the video signal corresponding to the first or second image is set at 1/1/1 of the writing speed in units of signals for one horizontal scanning line.
The video signal is read out from the memory (19) at a speed of 2 and thereby expanded twice in the vertical direction and sent to the D/A converter (21). As a result, the selected image is enlarged to its original size and displayed as shown in FIG. 8(f) or (g).

The circuit for time-compressing and recording the second video signal on a non-recording magnetic tape can be easily constructed using the circuit configuration shown in FIG. 1, as in the first embodiment. Of course, it is possible to construct a circuit for recording three channels of video signals with three times the time axis compression.

Toshu University 11 This embodiment relates to a recording circuit for recording two channels of video signals on a magnetic tape by dividing them into two tracks in a time-sharing manner without compressing the time axis. be.

As shown in FIG. 10, the signal tracks (33) of the magnetic tape (32) are used alternately as track portions A and track portions B, and as will be described later, the track portion A contains the video signal of the first channel (first video signal). One field of the video signal (signal) of the second channel is recorded, and track section B contains the video signal (signal) of the second channel.
One field of the second video signal) will be recorded.

In the circuit shown in FIG. 1, the operation that is different from the first embodiment is that the video signal written in the memory (4) is changed every one field period by the operation of the readout control circuit (6). They are read out at the same speed, and as a result, the first video signal V becomes an intermittent signal having video components only in odd or even fields.

The first video signal V sent to the recording signal processing circuit (10) includes a luminance signal Y and a chroma signal C of the first half period of one frame period, as schematically shown in FIG. 9(V). It includes a vertical synchronization signal VS, etc. in accordance with a normal signal format.

Further, in this embodiment, the switching circuit (12) shown in FIG. 1 is switched at a cycle of one frame period by a switching control pulse P, which will be described later.

The switching control pulse P causes the recording/reproducing head (13) to
During the scanning period of the track portion A shown in FIG. 0, that is, during the first division period, the signal becomes "H" as shown in FIG. 9(P), and the switching circuit (12) is switched to the terminal a side. As a result, the first video signal V is recorded on the track section.

Moreover, the control pulse P becomes "L" as shown in FIG. 9(P) during the period when the recording/reproducing head scans the track portion B in FIG. 10, that is, during the second division period, and the switching circuit ( 12)
is switched to the b side, and thereby the signal of track B is reproduced.

Note that the control pulse P can be easily created using, for example, a head switching pulse or the like as a phase reference.

When the switching circuit (12) is conductive to the terminal, the second video signal obtained from the regenerative amplifier circuit (14) includes the ninth
As schematically shown in Figure (V'), the luminance signal Y' and chroma signal C' of the latter half of one frame period, and the vertical synchronization signal VS' in accordance with the normal signal format are included. There is.

Therefore, by switching the switching circuit at the timing shown in FIG. 9(P), the first video signal is recorded on the track portion A of the magnetic tape in synchronization with the second video signal.

11(a) to (g), the first image to be newly recorded on the magnetic tape is shown in FIG. 11(a), and the second image already recorded on the magnetic tape is shown in FIG. 11(b). In this case, the effects achieved by the above circuit will be explained.

It should be noted that the second image is intermittently recorded every other field as shown in FIG. 3(d).

The first image becomes an intermittent signal for every other field as shown in Figure (C) by writing to and reading from the memory.
The image is combined with the second image as shown in FIG.

The first and second video signals recorded on the magnetic tape are selectively reproduced by a reproduction circuit, which will be described later, so that a signal corresponding to one of the images is reproduced as shown in FIG. 5(f) or (g). is enlarged and displayed on the screen of the television receiver.

There is also a reproduction circuit for selectively reproducing one of the images.
Although it has the same configuration as the circuit of FIG. 2 in the first embodiment,
In this embodiment, the video signal corresponding to the first or second image is stored in the memory (without interpolating missing fields).
19), and thereby a continuous video signal is sent to the D/A converter (21).

As a result, one of the selected images is shown in FIG. 11(f) or (
As shown in g), it is displayed as the original continuous signal.

The drawings and the description of the above-mentioned embodiments are for explaining the present invention, and should not be construed to limit or reduce the scope of the invention described in the claims.

Further, the configuration of each part of the present invention is not limited to the first and second embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a multi-channel recording circuit in which the present invention is implemented in a VTR, FIG. 2 is a block diagram of a playback circuit used together with the circuit of FIG. 1, and FIG. FIG. 4 is an explanatory diagram showing the signal track of the magnetic tape in the first embodiment. FIG. 5 is an explanatory diagram showing the state of image processing in the first embodiment. 1st in 2 embodiments
FIG. 7 is an explanatory diagram showing the signal track of the magnetic tape in the second embodiment. FIG. 8 is an explanatory diagram showing the state of image processing in the second embodiment. 1 is a timing chart explaining the circuit operation of FIG. 1 in the third embodiment, and FIG.
FIG. 11 is an explanatory diagram showing the signal track of the magnetic tape in the embodiment, FIG. 11 is an explanatory diagram showing the state of image processing in the third embodiment, and FIG. 12 is a block diagram of a conventional circuit.

Claims (2)

[Claims] (1) A switching circuit (1
2) connecting the signal recording means and the signal reproducing means via;
The switching circuit (12) switches to the signal recording means side during the first divided period in each horizontal scanning period and to the signal reproducing means side during the second divided period at a cycle of one horizontal scanning period, and the signal recording means switches the signal recording means to the signal reproducing means side during the second divided period. a memory (4) into which a first video signal to be recorded on a recording medium is written at a predetermined period; and a control circuit (6) which reads out the first video signal from the memory (4) after compressing the time axis in the horizontal scanning direction. The signal reproducing means includes a reproducing circuit (15) for reproducing the second video signal recorded in each signal track with time axis compression in the horizontal scanning direction,
The output end of the reproduction circuit is connected to a control circuit (6), and the control circuit (6) controls the reproduction of each of the first divisions at a timing synchronized with the compressed second video signal reproduced in each of the second division periods. A multi-channel recording circuit characterized in that a control signal for reading a compressed first video signal from a memory (4) within a period is created and supplied to the memory (4). (2) A switching circuit (1
2) connecting the signal recording means and the signal reproducing means via;
The switching circuit (12) switches to the signal recording means side during the first divided period in each field period and to the signal reproducing means side during the second divided period at a cycle of one field period, and the signal recording means switches to the signal recording medium side during the second divided period. a memory (4) into which a first video signal to be recorded is written at a predetermined period;
a control circuit (6) for compressing the first video signal in the vertical scanning direction and reading it out; comprising a reproducing circuit (15) for reproducing the signal;
The output end of the reproduction circuit is connected to a control circuit (6), and the control circuit (6) controls the reproduction of each of the first divisions at a timing synchronized with the compressed second video signal reproduced in each of the second division periods. A multi-channel recording circuit characterized in that a control signal for reading a compressed first video signal from a memory (4) within a period is created and supplied to the memory (4).