JP2825258B2 - Dubbing control device - Google Patents

Description

The present invention relates to a dubbing control device that controls whether dubbing from a digital video tape recorder to an analog video tape recorder is possible.

(Prior Art) In recent years, in a video tape recorder (hereinafter, referred to as a VTR), a so-called digital VTR for converting a video signal into a digital signal for recording and reproducing has been developed.

According to this digital VTR, higher image quality can be achieved than a so-called analog VTR that records and reproduces a video signal in the form of an analog signal. Thereby, there is an advantage that the image quality does not deteriorate in principle even if dubbing is repeated.

However, such advantages may lead to infringement of the copyright of the soft tape when dubbing the soft tape.

Therefore, it is necessary to control whether dubbing is possible or not by some method.

Here, a conventional method for controlling whether dubbing is possible or not will be described.

Conventionally, in a digital VTR, a dubbing permission / inhibition signal for instructing whether or not dubbing is to be recorded in advance on a soft tape or the like, and whether or not dubbing is permitted is controlled based on the dubbing / non-permission instruction signal. That is, as shown in FIG. 4, a dubbing enable / disable instruction signal is supplied from the digital VTR 11 on the reproducing side to the digital VTR 13 on the recording side via the digital interface 12, and the digital VTR 1 on the recording side is supplied.
In step 3, whether dubbing is permitted or not is controlled based on the dubbing permission / inhibition signal. This method is the same as the method of controlling dubbing availability used in digital audio tape recorders and the like.

However, this method, as shown in FIG.
Analog V to VTR11 via analog interface 14
This is not applicable when connecting TR15 and dubbing from digital VTR11 to analog VTR15.

This is in this case the newly manufactured analog VT
This is because it is necessary to control not only R but also whether or not dubbing is performed on a conventional analog VTR.

By the way, in the analog VTR, a method of inhibiting dubbing by changing the vertical blanking waveform to a waveform different from the original waveform as shown in FIG. 6 has been conventionally adopted. FIG. 6 shows a waveform in one horizontal scanning period (1H) in the vertical blanking period. In some cases, such a waveform is formed over, for example, seven horizontal scanning line periods, or in each horizontal scanning period. For example, the amplitude of the waveform is changed every time.

This does not affect the display on the television receiver at all, but if dubbing is performed with another analog VTR, the automatic gain control circuit of the recording circuit malfunctions. As a result, the video signal is disturbed, and dubbing is substantially prohibited.

If this method is applied to prohibiting dubbing of a digital VTR, in principle, dubbing from a digital VTR to a digital VTR as well as dubbing from a digital VTR to a conventional analog VTR can be prohibited.

However, in practice, this method cannot be adopted in a digital VTR. This is because the digital VTR does not record and reproduce during the blanking period, but records and reproduces only during the actual screen period. The reason why the blanking period is not recorded or reproduced is to reduce the number of recording bits to save tape consumption.
At the time of reproduction, the blanking waveform is inserted into the reproduction output during the actual screen period.

In such a configuration, even if the waveform in the blanking period is changed in advance, since the blanking waveform is not actually recorded or reproduced, it is not possible to control whether dubbing is possible.

(Problems to be Solved by the Invention) As described above, conventionally, a digital VTR is used instead of an analog VTR.
There was no effective way to control whether dubbing to TR was possible.

Therefore, an object of the present invention is to provide a dubbing control device that can control whether dubbing from a digital VTR to an analog VTR is possible.

[Means for Solving the Problems] A dubbing control device according to the present invention is a recording device in which a composite signal including a video signal and a dubbing enable / disable instruction signal for instructing whether or not dubbing of the video signal is recorded is recorded. Reproducing means for reproducing the composite signal from the medium; extracting means for extracting a dubbing permission / inhibition signal from the composite signal reproduced by the reproducing means; and a blanking waveform permitting dubbing of the video signal reproduced by the reproducing means. A first memory in which a signal held by the first memory is recorded, and dubbing of a video signal reproduced by the reproducing means, wherein a part of the video signal can be dubbed by changing its amplitude as time passes. A second memory storing a signal having a blanking waveform to be obtained, and a dubbing enable / disable instruction signal extracted by the extracting means. It is obtained so as to include a blanking waveform setting means for inserting the blanking period of the reproduced video signal by selectively taking out reproducing means 1 and the signal recorded in the second memory.

(Operation) According to the above configuration, first, the blanking waveform of the video signal is set based on the dubbing enable / disable instruction signal obtained at the time of reproduction.
From a VTR that does not record and reproduce the blanking period like R,
It is possible to control whether dubbing can be performed on an analog VTR that can control dubbing using a blanking waveform.

In addition, since the amplitude of the blanking waveform that prohibits dubbing of the video signal is changed with time, dubbing of some video signals is possible, so it is possible to distinguish it from failure Becomes

Further, a signal having a blanking waveform for permitting dubbing of the video signal is recorded in the first memory, and a signal having a blanking waveform for inhibiting dubbing of the video signal is recorded in the second memory. For example, in the case where the dubbing-prohibited blanking waveform is inappropriate in waveform depending on the system, there is an advantage that only the second memory needs to be replaced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a configuration of one embodiment of the present invention.

In FIG. 1, reference numeral 21 denotes a tape head system for reproducing a digital composite signal from a magnetic tape by a magnetic head. Here, the digital composite signal is a digitally coded signal including a digitally coded video signal and at least a 1-bit dubbing enable / disable instruction signal. in this case,
The video signal is recorded and reproduced only during the actual image period in order to save tape consumption.

The digital composite signal reproduced by the tape head system 21 is returned to a digital signal by the digital data reproducing circuit 22. The digital data reproducing circuit 22 includes a phase locked loop circuit for reproducing a bit clock,
Judgment circuit for judging each bit 1, 0, synchronization detection circuit for synchronizing each word, deinterleave circuit for deinterleaving interleaved data for burst error, error due to dropout, etc. Includes an error correction circuit to detect and correct the signal, a time base collector (TBC) to remove the temporal fluctuation (jitter) of the reproduction signal from the magnetic tape, etc. These are the same as the conventional digital VTR. Therefore, detailed description is omitted.

The output of the digital data reproduction circuit 22 is decoded by the video signal reproduction processing circuit 23 into digital data of a video signal. This decoded output is supplied to one terminal of the switch circuit 24.

The output of the digital data reproduction circuit 22 is also supplied to an ID word detection circuit 25. This ID word detection circuit 25
Detects an ID word from input data. In this detection, for example, a word of a predetermined number in digital data is determined in advance as an ID word (a plurality of words may be used),
At the time of reproduction, the reproduction timing is determined by counting the order of the digital words for each field. This is the same as the conventional one.

The detected ID word is supplied to a dubbing enable / disable instruction signal detecting circuit 26. This dubbing enable / disable instruction signal detection circuit
The number 26 determines the reproduction timing of the dubbing permission / inhibition signal by counting the bit of the predetermined number in the predetermined ID word by the bit clock. Then, by latching the input data at the determined timing, a dubbing enable / disable instruction signal is detected. This detection output is supplied to the switch circuit 29 as a control signal.

The switch circuit 29 selects one of the readout outputs of the ROMs 27 and 28 based on the detection output of the dubbing enable / disable instruction signal detection circuit 26. Here, the ROM 27 generates a signal having the same waveform as the original blanking waveform of the video signal. On the other hand, the ROM 28 generates, for example, a signal having a blanking waveform that can cause the automatic gain control circuit described above with reference to FIG. 6 to malfunction.

The switch circuit 29 selects the read output of the ROM 28 when the dubbing permission / inhibition instruction signal indicates the prohibition of the dubbing. On the other hand, when instructing dubbing permission,
Select the read output of This selection output is supplied to the other terminal of the switch circuit 24.

The reading of the ROMs 27 and 28 is controlled by a timing generation circuit (not shown). This timing generation circuit reads the ROMs 27 and 28 during the blanking period in synchronization with the reproduced digital composite signal.

The switch circuit 24 performs a blanking period based on the timing signal output from the timing generation circuit,
ROM 27 or ROM 28 supplied via a switch circuit 29
And the output of the video signal reproduction processing circuit 23 is selected during periods other than the blanking period. As a result, a digital video signal in which the read output of the ROM 27 or the ROM 28 is inserted during the blanking period is obtained. This digital video signal is converted into an analog signal by the digital / analog conversion circuit 30. This converted output is supplied to an output terminal 32 through an amplifier 31.

FIG. 2 shows a video signal obtained in this way using a screen.

In FIG. 2, reference numeral 41 denotes a screen for one field. In this screen, reference numeral 42 corresponds to a real screen portion of the video signal, and reference numeral 43 corresponds to a blanking portion. Actual recording and reproduction are performed only on the real screen section 42 as described above.

 FIG. 3 is a diagram showing an example of the configuration of an ID word.

As shown in the figure, n + 1 words of 0 to n are provided per field. And
Bit 7 of the (n + 1) th ID word n is assigned to a bit indicating whether dubbing to the analog VTR is possible,
Bit 6 is assigned to a bit indicating whether dubbing is possible for the digital VTR. When the data of these bits is "1", for example, prohibition of dubbing is instructed, and when the data of these bits is "0", permission of dubbing is instructed.

As described above, in this embodiment, at the time of reproduction, by setting the blanking waveform of the video signal based on the dubbing enable / disable instruction signal, whether or not dubbing is controlled by this blanking waveform is controlled. As described above, it is possible to control whether dubbing can be performed on an analog VTR that can control dubbing using a blanking waveform from a VTR that does not record and reproduce a blanking period.

Note that the present invention is not limited to the above embodiment.

For example, in the above embodiment, the case where the dubbing enable / disable instruction bit for the digital VTR and the dubbing enable / disable instruction bit for the analog VTR are provided independently is described, but they may be shared.

In the above-described embodiment, the case where the ID word and the dubbing permission / inhibition signal are provided for each field has been described. In this case, the dubbing permission / inhibition instruction information may be latched until the next reproduction time.

Further, in the above embodiment, the case where the ROMs 27 and 28 are provided independently has been described. However, a part may be shared to reduce the number of bits.

Also, lower the bit clock from within the normal screen,
The clock cycle may be delayed until the resolution required to generate a blanking waveform.

Instead of a ROM, a counter and a decoder may be combined to generate a blanking waveform.

Also, instead of using the read output of the ROM as it is,
Processing such as intermittent output or changing the amplitude over time may be added. In this case,
Since some screens can be recorded, it is easy to distinguish them from failures.

The dubbing prohibition operation can be performed simultaneously with the digital interface, or can be made independent by another prohibition bit as described above. In addition, audio can be performed simultaneously or independently.

Alternatively, dubbing prohibition may be displayed by an operation indicator or a screen.

Further, the present invention is also effective when recording on a digital VTR using an analog interface.

In addition, a method of canceling the dubbing prohibition may be added according to payment of some copyright fee.

In addition, dubbing can be performed a predetermined number of times or up to a predetermined generation.

Further, the present invention is applicable not only when the video signal recorded on the magnetic tape is a digitally encoded video signal but also when it is an analog video signal.

The present invention is also applicable to a dubbing control device of a video signal reproducing device other than a VTR.

[Effects of the Invention] As described above, the present invention can reliably control whether dubbing can be performed even when dubbing a signal reproduced by a digital VTR to a conventional analog VTR, and furthermore, a television receiver Is not affected at all. Therefore, the present invention is extremely effective for copyright protection and the like.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing the configuration of one embodiment of the present invention, and FIG.
FIGS. 3 and 4 are diagrams for explaining the operation of FIG. 1, FIGS. 4 and 5 are diagrams for explaining a connection example of dubbing, and FIG. 6 is a conventional method for controlling whether dubbing can be performed. It is a figure for explaining. 21: tape head system, 22: digital data reproduction circuit, 23: video signal reproduction processing circuit, 24, 29 ... switch circuit, 25 ... ID word detection circuit, 26 ... dubbing enable / disable instruction signal detection circuit , 27, 28 ROM, 30 digital / analog conversion circuit, 31 amplifier, 32 output terminal.

Claims (1)

(57) [Claims] 1. A reproducing means for reproducing a composite signal from a recording medium on which a composite signal including a video signal and a dubbing permission / inhibition instruction signal for instructing whether or not dubbing of the video signal is recorded, is reproduced by the reproducing means. Extracting means for extracting the dubbing permission / inhibition signal from the composite signal, a first memory storing a signal having a blanking waveform permitting dubbing of the video signal reproduced by the reproducing means, A dubbing of the video signal reproduced by the means is prohibited, and a signal having a blanking waveform capable of dubbing a part of the video signal by changing its amplitude with time is recorded. A second memory; and a second memory configured to store data in the first and second memories based on the dubbing permission / inhibition signal extracted by the extracting unit. A dubbing control device, comprising: a blanking waveform setting means for selectively taking out a recorded signal and inserting the signal into a blanking period of the video signal reproduced by the reproducing means.