JPH0478065A - Video tape recorder - Google Patents

Abstract

PURPOSE:To prohibit many and unspecific third persons from watching recording contents by making video and audio information in a part recorded with a password code impossible to be outputted even when the information is reproduced at the time of reproducing a tape concerned. CONSTITUTION:A password code inputted from an input means 14 is stored by a storage means 6, and the password code is encoded and written on a tape via a control head 1 by a password code write means. A signal read out via a control head 2 from a control track of the tape is decoded so that the password code is reproduced by a code reproducing means, while the reproduced password code at the time of reproducing the video or audio information of the tape is compared with the stored password code in the storage means 6 by a comparing means 10, and if both codes are not coincident with each other, the reproduced video signal and audio signal are never outputted. By this method, the third persons are prohibited from watching the contents of the recorded tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a video tape recorder having a function of preventing third parties from viewing recorded contents recorded on a tape.

(Prior Art) Conventionally, even if a tape on which some information is recorded by a video tape recorder (VTR) is recorded by a third party, it is still possible to use a VTR of the same type as the VTR used for recording.
If the recording tape is set on the computer, the recorded contents can be played back and viewed freely. Therefore, if you do not want a third party to see the contents recorded on the tape, you must carefully store the recording tape and prevent it from being passed on to others. The current situation is that there is no way to do so. However, when you do not want to show all or part of the content recorded on a tape to a third party, some VH8 home VTRs send digital signals (such as cue code, punch code, time code, etc.) to the control track. ) can be recorded and played back, and can show the joints of video and audio recorded on a tape, as well as the position from the reference point of the tape.

Figure 2 shows how to write to the control track °“0°
This diagram shows pulse waveforms showing the duty ratio of the CTL signal corresponding to ° and 1'°. There is.

Figure 3 shows an example in which the CTL signals "○°°" and "1'" are used as cue codes, and are written on the control track as shown in the figure.
This is an example of recording a user code and time code on a control track using the CTL signal of '°. Since the user code can contain additional information to the information recorded on the tape, However, such a VTR has not been developed at present.

(Problems to be Solved by the Invention) Conventionally, recorded tapes can be played back and viewed if there is a VTR of the same type as the VTR used when information was recorded on the tape. Once the recording tape is handed over to a third party, there is a drawback in that there is no effective means to prevent the third party from viewing the contents of the recording tape.

Therefore, the present invention eliminates the above-mentioned drawbacks, and when playing a tape, even if the video and audio information of the part where the PIN code is recorded is played back, it is possible to prevent the video and audio information of this part from being output. The purpose is to provide a video tape recorder.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a video tape recorder having a CTL coding function for reading and writing a code on a control track of a tape via a control head, and an input means for inputting a password code, and an input means for inputting a password from the input means. storage means for storing the password code stored in the storage means; password code writing means for encoding the password stored in the storage means and writing it onto the tape via the control head; a code reproducing means for decoding a signal read out through the tape and reproducing a PIN code; and a PIN code reproduced by the code reproducing means and stored in the storage means when the video or audio information of the tape is reproduced. and a mute control means that does not output the reproduced video signal and audio signal if the two codes do not match according to the comparison means.

(Function) In the video tape recorder of the present invention, the input means inputs a password. The storage means stores the password input from the input means.

The password code writing means encodes the password stored in the storage means and writes it onto the tape via the control head. The code reproducing means decodes the signal read from the control track of the tape via the control head and reproduces the personal identification code. The comparison means compares the password code reproduced by the code reproduction means and the password code stored in the storage means when reproducing the video or audio information of the tape. The mute control means does not output the reproduced video signal and audio signal if the two codes do not match according to the comparison means.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the video tape recorder of the present invention. 1 is a write-only CTL head that records the PIN code on the control track of the tape.
2 is a read-only CTL head that plays the pin code from the control track of the tape, 3 is a read-only C
a CTL decoder that converts the signal reproduced by the TL head 2 into a recited code; 4 is a code writing control signal;
00 is a switch circuit that turns on and off the supply of data to the write-only CTL head 1, and 5 is a CTL that converts the code to be recorded into a signal that can be recorded on tape.
Encoder, 6 is a memory that stores the password input from the input unit 14, 7 is a memory that stores the rewrite code input from the input unit 14, and 8 turns the switch circuit 9 on and off depending on the operating mode of the device. 9 is a switch circuit that is turned on and off by the mode control circuit 8; 10 is a read-only CTL head 2;
11 is a video/audio playback circuit that plays video and audio signals from the tape; 12 is a comparison circuit that compares the code read out by the input unit 14 with the code input from the input section 14; A switch circuit for switching whether or not to output the video and audio signals output from the video and audio reproduction circuit 11 to an output section 13 consisting of a cathode ray tube and a speaker, 13 an output section consisting of a cathode ray tube and a speaker, and 14 a password code. The key is a manual input section.

Here, the input section 14 serves as an input means, the memory 6 serves as a storage means, the write-only CTL head 1 and the CTL encoder 5
constitutes a code writing means, the read-only CTL head 2 and CTL decoder 3 constitute a code reproducing means, the comparison circuit 10 constitutes a comparison means, and the switch circuit 12 constitutes a mute control means.

Next, the operation of this embodiment will be explained. In a recording mode in which video signals and the like are recorded on a tape, the user inputs a password from the input unit 14 in advance, so this password is stored in the memory 6.

Also, at this time, the switch circuit 9 is turned on by mode control circuit #18, and the code write signal 100 becomes active, turning on the switch circuit 4.
It is now connected to the L head 1. In this state, when recording of video and audio signals is started, the CTL encoder 5 converts the PIN code in the memory 6 into a recordable format,
This is read out via the switch circuit 9.4 and the dedicated CT
Supplied to L head 1. As a result, the password code is continuously recorded on the control track of the tape. Of course, at this time, video and audio signals are recorded on the bio track of the tape by a video head (not shown).

Next, the operation of the apparatus will be described when playing back a tape in which video and audio signals are recorded on the video track and a password is recorded on the control track as described above. During reproduction, a signal reproduced from the control track of the tape by the read-only CTL head 1 is converted by the CTL decoder 3 into a code having a predetermined format, and then input to the comparator circuit 10. At this time, the comparator circuit 10 compares the recorded PIN code held in the memory 6 with the PIN code reproduced as described above, and if the two match, the switch f
The iJ 12 is switched to the terminal side so that the video and audio signals output from the video and audio reproduction circuit 11 are not supplied to the output section 13, thereby muting these signals. Therefore, the user cannot reproduce and view the video and audio signals of the portion of the tape where the PIN code is recorded.

Here, if the user wishes to view the muted portion of the tape, the mute can be canceled by inputting the same number as the password recorded on the tape from the input unit 14. That is, in this case, in the comparison time 110, C
The PIN code from the TL decoder 3, the PIN code held in the memory 6, and the PIN code from the input section 14 are input, and only when all of these PIN codes match, the PIN code from the CTL decoder 3 and the PIN code stored in the memory are input. Even if the PIN code held in 6 matches, the switch times &!
Leave 12 on the terminal a side without changing it to the terminal a side. As a result, the video and audio signals output from the video and audio playback diagram ill are sent to the output section 13 via the switch circuit 12, so that the video and audio of the portion where the PIN code is recorded can be viewed. It becomes like this.

By the way, if the user does not know the password recorded on the tape and attempts to rewrite only the CTL code in order to reproduce the muted video and audio signals, the device will perform the following procedure. Perform a similar action. First, a rewriting password is input by the user from the input unit 14, but in this case, the input data is stored in the memory 7. Therefore, the password code recorded on the tape during recording remains in the memory 6. Furthermore, in the case of user code rewriting, the control signal 100 becomes active and the switch circuit 4 is turned on, but the switch circuit 9 initially remains off.

Thereafter, when the tape is run, the read-only CTL head 2, which can reproduce the control track in advance of the write-only CTL head 1, reads out a signal corresponding to the password from the control track, and this is transmitted to the CTL recorder. 3, it is converted into the original password code form and input to the comparator circuit 10. As a result, the comparator circuit 10 compares the recorded PIN code held in the memory 6 with the PIN code reproduced as described above, and determines whether the two match or not in the mode control diagram B8.
Let me know. Upon receiving this, the mode control circuit 8 keeps the switch F49 off if the two codes match. Therefore, even if the rewrite data held in the memory 7 is converted into a recordable form by the CTL encoder 5, this signal is not supplied to the write-only CTL head 1. For this reason, the control track on the tape cannot be rewritten, the originally recorded PIN code is prevented from being rewritten, and the tape portion where the PIN code is recorded is muted in the same way as above. I can't see it.

However, in the comparison circuit, if the two pin codes do not match, the mode control diagram FI! 48 is the switch circuit 9
By turning on, connecting the write-only CTL head 1 to the CTL encoder 5, and supplying the output signal of the CTL encoder 5 to the write-only CTL head 1,
A rewrite code is written to the tape's control track.

According to this embodiment, when a tape on which a PIN code is recorded is set in the device of this example, a user who knows the PIN code can freely play back the portion on which the PIN code is recorded. Since an unknown user cannot reproduce and view the portion where the password code is recorded, it is possible to prevent the contents of the tape recording from being shown to an unspecified number of third parties. Furthermore, using the device of this example, it is possible to rewrite the PIN code to any part of the tape that has already been recorded, so that the recorded contents of any part of the tape cannot be disclosed to a third party. You can make it invisible.

〔Effect of the invention〕

As described above, according to the video tape recorder of the present invention, even if the video and audio information in the part where the PIN code is not recorded is played back during tape playback, it is possible to prevent this from being output. It is possible to prevent the information from being shown to an unspecified number of third parties.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the video tape recorder of the present invention, and FIG. 2 is a pulse diagram showing the duty ratio of the CTL signal corresponding to 0°' and "1'° written in the control track. The waveform diagram, Fig. 3, is a diagram showing an example of a cueing code formed using the above-mentioned 0pa and °゛1゛° CTL signals, and Fig. 4 is a diagram showing an example of a cue code formed using the above-mentioned 0pa and 1°' CTL signals. It is a block diagram showing an example of formed user code and time code.l...Write-only CTL head 2...Read-only CTL head 3...CTL decoder 4.9.12...Switch circuit 5. ... CTL encoder 6.7 ... Memory 8 ... Mode control circuit 10 ... Comparison circuit 11 ... Video and audio reproduction circuit 13 ... Output section 14 ... Input section

Claims (1)

[Claims] A video tape recorder having a CTL coding function for reading and writing codes on a control track of a tape via a control head includes an input means for inputting a code, a storage means for storing the code input from the input means, and PIN code writing means for encoding a PIN code stored in a storage means and writing it onto a tape via the control head; and a PIN code for decoding a signal read from a control track of the tape via the control head. a code reproducing means for reproducing the video or audio information of the tape, a comparison means for comparing the password code reproduced by the code reproduction means and the password stored in the storage means when reproducing the video or audio information of the tape, and the comparison means A video tape recorder comprising mute control means that does not output the reproduced video signal and audio signal if the two codes do not match.