JPH05314739A - Time code signal generating device and magnetic reproducing device - Google Patents

Abstract

PURPOSE:To output a time code signal coincident with a reproducing picture in value by generating the time code signal in synchronization with a reproducing time code signal based on time data to be inputted in prescribed timing as a reference. CONSTITUTION:The time data VITC reproduced by a video signal circuit 2 is stored in a register 20 by a time code signal producing circuit 8, and the time data is stepped in accordance with a stepping pulse WP with a reference of the VITC, and also the contents of the register 20 are renewed, and then time data DTC of changing values in turn by following a reproducing speed of the reproducing time code signal STC is generated. That is, the time data from the register 20 is inputted to a computing element 21, where this data is renewed with the stepping pulse WP as the reference. At this time, the time data is renewed by the computing element 21 in the way of addition or subtraction according to the reproducing direction, and hence the time data DTC of changing values in turn by following the reproducing speed of the signal STC is generated, and is accumulated in a register 22 and afterward outputted to a time code signal generating circuit 18.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology Problem to be Solved by the Invention Means for Solving the Problem (FIGS. 1 and 2) Action (FIGS. 1 and 2) Example (1) Overall Configuration (FIG. 1) (2) ) Time code signal generation circuit (Fig. 2) (3) Operation unit (Fig. 3) (4) Effect of the embodiment (5) Other embodiment Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time code signal generating device and a magnetic reproducing device, and can be applied to, for example, a video tape recorder for converting a video signal into a digital signal for recording and reproducing.

[0003]

2. Description of the Related Art Conventionally, a video tape recorder has been designed so that a video signal can be converted into a digital signal (hereinafter referred to as a digital video signal) for recording and reproduction. That is, in the digital video signal, the image quality does not deteriorate even if the signal processing is repeated. Therefore, even if the dubbing is repeated, the image quality of the reproduced image can be prevented from being deteriorated by using the error correction processing in combination.

[0004]

By the way, in this type of video tape recorder, it is considered that the recording density can be improved by recording and reproducing a digital video signal by combining data compression and expansion processing.

However, when this kind of processing is applied to a digital video signal, the signal processing requires a time period of several ruils, so that the relationship between the time code signal and the time data of the actual reproduced image depends on the reproduction speed. There are changing issues. That is, in the time code signal, it is necessary to reproduce even in the case of fast-forward reproduction,
It is necessary to form a recording track in the longitudinal direction of the magnetic tape and record continuously.

Therefore, the time code signal can be recorded / reproduced in real time, whereas the digital video signal is recorded / reproduced with a delay of a predetermined period.

At this time, for example, if the digital video signal is 3
When recording / reproducing with a field delay, the digital video signal is recorded on the magnetic tape with a delay of 3 fields from the actual time code signal, and in normal reproduction, it is delayed by 3 fields, resulting in a time code. The reproduced image is delayed by 6 fields with respect to the signal. On the other hand, in the case of reproducing in the reverse direction at the same speed as the normal reproduction, in this case, the time code signal is reproduced in advance by 3 fields, so that the delay time during recording is canceled during reproduction. The time code signal and the reproduced image match and are reproduced.

Therefore, if the relationship between the time code signal and the reproduced image changes according to the reproduction speed in this way, the reproduced image cannot be processed with the time code signal as a reference.
There is a problem that it is difficult to work with the conventional editing device.

The present invention has been made in consideration of the above points. Even when a digital video signal is recorded / reproduced by applying data compression / expansion processing or the like, a time code signal whose value matches a reproduced image is generated. An attempt is made to propose a time code signal generating device and a magnetic reproducing device that can output.

[0010]

In order to solve such a problem, in the first invention, in synchronization with a time code signal STC whose value continuously changes, based on time data VITC input at a predetermined timing. The variable time data DTC whose value changes continuously is generated, and the time code signal TC synchronized with the time code signal STC is generated according to the variable time data DTC.

Further, in the second invention, the time code signal STC is recorded on the longitudinal track extending in the longitudinal direction, and the time data VITC and the video signal DV are recorded on the recording tracks formed obliquely in the longitudinal direction. 2 in the magnetic reproducing apparatus 1 for reproducing the video signal DV, the time data reproducing means 2, 4 for reproducing the time data VITC and outputting the reproduced time data VITC,
A time code signal reproducing means 10 for reproducing the time code signal STC and outputting the reproduced time code signal STC;
Timing signal generation means 14 and 16 for generating timing signal STP synchronized with reproduction time code signal STC from reproduction time code signal STC, and timing signal ST
Time code signal generation means 18, 20, 21, 22 for generating a time code signal TC corresponding to the reproduction time data VITC with P as a reference is provided.

Further, in the third invention, the timing signal generating means 14 and 16 are provided with the reproduction time code signal ST.
A clock extraction circuit 14 for extracting the C bit clock signal CK and a signal generation circuit 16 for generating a timing signal STP whose signal level changes in synchronization with the bit clock signal CK are provided.

[0013]

[Operation] Time data VI input at a predetermined timing
Based on TC, variable time data DTC whose value continuously changes is generated in synchronization with time code signal STC whose value continuously changes, and time synchronized with time code signal STC is generated according to variable time data DTC. Code signal T
If C is generated, the time code signal STC corresponding to the time data VITC can be generated.

At this time, the reproduction time data V is reproduced from the magnetic tape 2 on which the time data VITC and the video signal DV are recorded.
The ITC and the reproduction time code signal STC are reproduced, the timing signal STP synchronized with the reproduction time code signal STC is generated from the reproduction time code signal STC, and the reproduction time data V is based on the timing signal STP.
If the time code signal TC corresponding to the ITC is generated, the time code signal TC corresponding to the video signal DV can be output.

Further, at this time, the reproduction time code signal S
If the bit clock signal CK of TC is extracted and the timing signal STP whose signal level changes in synchronization with this bit clock signal CK is generated, this timing signal ST
The time code signal TC can be simply generated using P.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings.

(1) Overall Structure In FIG. 1, reference numeral 1 denotes a video tape recorder as a whole, which records and reproduces a digital video signal DV.

Therefore, in the video tape recorder 1, the digital video signal is subjected to data compression processing by the video signal processing circuit 2 to be converted into recording data, and predetermined time data VITC is added to the magnetic head 4 for output to the magnetic head 4. Thus, a digital video signal is recorded on the magnetic tape 6 at a high density. At this time, in the video tape recorder 1, a time code track is formed in the longitudinal direction of the magnetic tape 6,
The time code signal TC is recorded in this time code track.

On the other hand, at the time of reproduction, in the video tape recorder 1, the reproduction signal output from the magnetic head 4 is demodulated by the video signal processing circuit 2 and then the data is expanded to output the digital video signal DV. At this time, the digital video signal DV is decompressed and outputted, so that it is outputted after being delayed by a predetermined field with respect to the reproduced signal.

The video signal processing circuit 2 reproduces the digital video signal, and simultaneously records the time data V recorded.
The ITC is reproduced and this time data VITC is output to the time code signal generation circuit 8. The time code signal generation circuit 8 receives a time code signal (hereinafter referred to as a reproduction time code signal) STC reproduced from the time code track via the magnetic head 10 and uses the reproduction time code signal STC as a reference to obtain time data. By regenerating the time code signal TC based on the above, the time code signal TC whose value matches the digital video signal DV and which changes in synchronization with the reproduction time code signal STC is output.

As a result, the video tape recorder 1 can output the time code signal TC that matches the reproduced image even when the digital video signal DV is output with a delay.

(2) Time code signal generation circuit As shown in FIG.
The reproduction time code signal STC is given to the bit clock extraction unit 14 having the L circuit configuration, and the reproduction time code signal S
The bit clock signal CK of TC is extracted.

Further, the time code signal generation circuit 8 outputs the reproduction time code signal STC to the timing generator 16 and detects the sync pattern of the reproduction time code signal STC with reference to the bit clock signal CK to reproduce the reproduction time code signal STC. A step-up pulse WP whose signal level rises in frame units of the time code signal STC is generated.
Further, the timing generator 16 generates a timing pulse signal STP for time code signal generation based on the sync pattern and the bit clock signal CK and outputs it to the time code signal generation circuit 18. As a result, the time code signal generation circuit 18 causes the timing pulse signal S
The time code signal TC is generated so as to match the digital video signal DV with reference to TP.

Therefore, the time code signal generation circuit 8 is
When the time data VITC is reproduced by the video signal processing circuit 2, the time data VITC is stored in the set time data register 20.

In the video tape recorder 1, the position of the magnetic head mounted on the rotary drum is displaced in accordance with the scanning position in the variable speed reproduction mode, whereby the digital head is intermittently changed in accordance with the reproduction speed. It is designed to play video signals.

Therefore, the time data VITC reproduced by the video signal processing circuit 2 is reproduced corresponding to the intermittently reproduced digital video signal, so that the value is intermittently changed in the variable speed reproduction. Is played to change. For this reason, in this embodiment, the time code signal generation circuit 8 uses the reproduced time data VI.
TC is stored in the set time data register 20, the time data is advanced in accordance with the step pulse WP with reference to the time data VITC, and the contents of the set time data register 20 are updated. The time data DTC whose value sequentially changes in accordance with the reproduction speed of the STC is generated.

That is, the arithmetic unit 21 inputs time data from the set time data register 20 and updates this time data with reference to the step pulse WP. At this time, the calculator 21 updates the time data by adding or subtracting the time data according to the reproduction direction, thereby generating the time data DTC whose value sequentially changes in accordance with the reproduction speed of the reproduction time code signal STC. As a result, the arithmetic unit 21 sequentially updates the contents of the set time data register 20 with the generated time data DTC,
Store TC in the output time data register 22.

The output time data register 22 stores the time data DTC and then outputs the time data DTC to the time code signal generation circuit 18 at a predetermined timing. As a result, the time code signal generation circuit 18 modulates the timing pulse signal STP based on the time data DTC, thereby matching the timing pulse signal STP with the digital video signal DV and reproducing the time code signal ST.
A time code signal TC that changes in synchronization with C is generated.

In this way, the time data VITC reproduced together with the video signal is sequentially updated to obtain the digital video signal D.
By generating time data DTC corresponding to V and changing in value in synchronization with the reproduction time code signal STC, and generating a time code signal TC in synchronization with the reproduction time code signal STC according to this time data DTC. ,
Even when the digital video signal is recorded and reproduced by applying the data compression / expansion process, the time code signal TC corresponding to the reproduced image can be output, and thus the time code signal TC can be used as a simple reference for the editing process. obtain.

(3) Arithmetic unit By the way, in the time code signal of the NTSC system,
There are so-called dropout frames, in this case 29
It is necessary to jump from frame to 02 and change the number of frames.

In this case, in a conventional time code generator or the like, time data is generated so that the number of frames sequentially changes by one value, and when the generated time data corresponds to a drop frame, the number of frames is added by a predetermined value. Then, the NTSC system time code signal is generated.

In the case of this method, however, it is necessary to repeat the addition process twice, and thus, in order to generate a continuous time code signal TC even in the case of variable speed reproduction,
There may be a case where the calculation processing time is insufficient. Furthermore, there is a problem that the entire configuration becomes complicated by the addition process being repeated twice.

Therefore, in this embodiment, the frame immediately before the drop frame is detected in advance, and the number of additions is switched in this frame to generate the time data DTC by one addition process.

That is, as shown in FIG. 3, in the arithmetic unit 21, the time data stored in the set time data register 20 is given to the DF detection circuit 28, and the frame immediately before the drop frame is detected here. Therefore, in the video tape recorder 1, a system control circuit (not shown) generates an addition / subtraction switching signal F / R whose signal level is switched according to the reproduction direction, and outputs it to each circuit block of the arithmetic unit 21.

When the magnetic tape 6 is reproduced in the normal reproduction direction based on the addition / subtraction switching signal F / R, the DF detection circuit 28 calculates

[Equation 1] Then, it is determined whether or not the calculation result DF rises to 1.

Here, F1 and F8 represent the 1-digit, 1-bit and 4-bit logical values of the frame data of the time data, and 10F2 represents the 10-digit and the 2-bit logical value of the frame data of the time data. .. Further, S1 and S8 are the 1 digit, 1 bit and 4 bit logical values of the second data of the time data, and 10S1 and 10S4 are the 10 digit, 1 bit and 4 bit logical values of the second data of the time data. , M
1 and M8 represent logical values of 1 digit, 1 bit and 4 bits of the minute data of the time data.

On the other hand, when reproducing the magnetic tape 6 in the reverse direction,

[Equation 2] Then, it is determined whether or not the calculation result DR rises to 1. Here, F2 and F4 are the 1-digit, 2-bit and 3-bit logical values of the frame data of the time data, and 10F1 is the 10-digit and 1-bit logical value of the frame data of the time data, S2 and S4. Is the 1 digit, 2 bits and 3 bits logical value of the seconds data of the time data, 10S2 is the 10 digits of the seconds data of the time data, 2
Represents the bit logical value. Further, M2 and M4 represent the logical value of 1 digit, 2 bits and 3 bits of the minute data of the time data.

As a result, the DF detection circuit 28 determines that the subsequent frame is a drop frame when the calculation processing result DF or DR of the equation (1) or (2) rises to the value 1, and generates the addition value based on the determination result. Output to the circuit 30. Here, the addition value generation circuit 30 switches the addition value based on the addition / subtraction switching signal F / R and the determination result of the DF detection circuit 28, and the magnetic tape 6 in the normal reproduction direction.
If the following frame is a drop frame and the following frame is not a drop frame, the value 00: 00: 00: 01 is added, whereas if the following frame is a drop frame, the value 00:
The added value of 00:00:03 is output.

On the other hand, when the magnetic tape 6 is reproduced in the reverse direction and the following frame is not the drop frame, the added value of the value 00: 00: 00: 29 is output, while the following frame is the drop frame. When value 00:00:
The added value of 00:27 is output.

The adder 32 adds the added value generated by the added value generating circuit 30 to the time data VITC in synchronization with the step pulse WP, and thereby the time data applicable to the NTSC system time code signal is added. Generate DTC. It is possible to generate the time data DTC by one addition process by determining whether or not the preceding frame is a dropout frame and switching the addition value based on the determination result to generate the time data. The time code signal can be reliably generated with a simple configuration.

(4) Effects of the Embodiments According to the above configuration, the video signal is delayed by generating the time code signal synchronized with the reproduction time code signal with reference to the time data reproduced together with the video signal. Even when the image is reproduced by playing back, the time code signal that matches the reproduced image can be output.

(5) Other Embodiments In the above embodiments, the case where the NTSC time code signal is generated has been described, but the present invention is not limited to this and is widely applied to various video tape recorders. be able to.

Further, in the above-mentioned embodiment, the case of recording and reproducing the digital video signal is described, but the present invention is not limited to this, and when recording and reproducing various video signals, it is not limited to the video tape recorder. It can be widely applied to the case where a time code signal is generated for a video signal reproduced by various video equipment.

[0044]

As described above, according to the present invention, the time data corresponding to the time data is generated by generating the time code signal synchronized with the reproduction time code signal with reference to the time data input at the predetermined timing. It is possible to obtain a time code signal generation device and a magnetic reproduction device that can output a time code signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a video tape recorder according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the time code signal generation circuit.

FIG. 3 is a block diagram showing the arithmetic unit.

[Explanation of symbols]

1 ... Video tape recorder, 2 ... Image signal processing device, 6 ... Magnetic tape, 8 ... Time code signal generation circuit, 14 ... Bit clock extraction section, 16 ... Timing generator, 18 ... Time code signal Generation circuit, 21 ...
... calculator, 28 ... DF detection circuit, 30 ... addition value generation circuit, 32 ... adder.

Claims (3)

[Claims] 1. A variable time data whose value continuously changes in synchronization with a time code signal whose value continuously changes based on time data input at a predetermined timing, and the variable time data is converted into the variable time data. A time code signal generating device, which generates a time code signal in synchronization with the time code signal. 2. A magnetic tape for reproducing a video signal from a magnetic tape having a longitudinal track extending in the longitudinal direction recorded with a time code signal, and time tracks and a video signal recorded on recording tracks formed obliquely in the longitudinal direction. In the reproducing apparatus, time data reproducing means for reproducing the time data and outputting reproduction time data, time code signal reproducing means for reproducing the time code signal and outputting a reproduction time code signal, and the reproduction time code signal To timing signal generating means for generating a timing signal synchronized with the reproduction time code signal, and time code signal generating means for generating a time code signal according to the reproduction time data with reference to the timing signal. Magnetic reproducing apparatus characterized by. 3. The timing signal generating means comprises a clock extraction circuit for extracting a bit clock signal of the reproduction time code signal, and a signal generation circuit for generating the timing signal whose signal level changes in synchronization with the bit clock signal. The magnetic reproducing apparatus according to claim 2, further comprising: