JPH06105284A - Video tape recorder - Google Patents

Abstract

PURPOSE:To control an operation at the time of reproduction, and to use data as the preservation and management-information of a video by recording the data of the user and manufacturing person of a VTR with the digital signal of the video on the tape of the VTR. CONSTITUTION:This device is equipped with a data inserting circuit 10 which inserts the digital data into a specific horizontal scanning period in the vertical blanking of a television signal. A system control part 7 operates the addition of the error correction code of the digital data, generates data indicating the attribute of the VTR, and data indicating each kind of condition at the time of recording, and outputs the data through a memory 9 to the data inserting circuit 10. Then, each kind of data is inserted into the vertical blanking period of a video signal by a gate pulse outputted by a gate signal generating circuit 11. Thus, the characteristic of the mechanism part of the VTR and the recording condition of the tape can be easily managed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for broadcasting stations, video program productions, etc., and particularly for video (video).
The present invention relates to a video tape recorder that records and reproduces digitized code data together with a signal and an audio (voice) signal.

[0002]

2. Description of the Related Art Commercial video tape recorders (hereinafter referred to as V
TR) is used for manufacturing video software for broadcasting and the like, and high quality performance is required. Further, such a VTR is required to have a function which has not been present, such as addition of a user bit indicating the code data of the user.

Due to advances in semiconductor technology and high-speed digital signal processing technology, digital processing has become possible not only for audio signals but also for video signals. The digital VTR is configured to A / D convert an analog video signal and add an error correction code for correcting a code error due to noise in the tape head system. Then, by distributing the recording order on the magnetic tape and the scanning order of the video signal according to a certain rule, even if a burst error occurs, the error correction of the image is finally performed so that it cannot be discerned by human eyes. . Further, such a VTR records a signal on a magnetic tape by performing a code conversion suitable for the characteristics between the tape and the head.

Since the digital VTR performs digital signal processing, the image quality evaluation ultimately depends on the error correction capability. For that purpose, the error rate (the number of code errors per unit time) is an important factor showing its capability.
In order to further increase the recording density, the track width is narrowed within the allowable error rate range and the tape speed is slowed down so that recording can be performed for a long time. Currently, digital VTRs for broadcasting and production are used.

In the current VTR for broadcasting, a magnetic tape is provided with a track dedicated to a time code representing hours, minutes, seconds and frames in a 24-hour system. By reading this time code, the current reproduction position of the tape is collated or the target position is searched. This time code is further provided with 8 bytes of user bits for each frame, and the user of the VTR can arbitrarily define and use these 8 bytes. However, the characters that can be used are 16 characters (0-
9, A, B, C, D, E, F), its usage is limited, and much information cannot be entered.

[0006]

Since the digital VTR is basically a device for recording / reproducing digital data,
Arbitrary code data (second digital data) can be recorded / reproduced if it can be distinguished from video data (first digital data). However, in adding this code data, if the standard television signal is deleted or added additionally, it becomes incompatible with the conventional standard television signal. Moreover, since it becomes inconvenient if the connection with other television equipment cannot be established, the existing television signal should be used without being changed. Fortunately, current television signals have blanking periods during which no signal is displayed on the CRT during the horizontal and vertical scanning periods of the CRT. This corresponds to the return period when scanning the electron beam of the CRT horizontally and vertically.

Therefore, even if a digital signal unrelated to the video signal is inserted, the video is not substantially affected, and the code data can be recorded / reproduced in the area not directly related to the video signal. One example of this is teletext. Since the teletext broadcast is premised on analog processing of a television signal, the amount of data that can be inserted in one horizontal synchronization section of the vertical blanking section is small.

Further, the conventional VTR for business uses the time code defined by the SMPTE standard to perform video addressing, but the amount of information is too small as a use area with 8 bytes for each frame. Therefore, such code data is valuable only to the VTR user as a reference.

The present invention has been made in view of the above conventional problems, and a video tape recorder capable of providing a large number of usages by dramatically increasing user bits in a commercial VTR. Aim to achieve. Therefore, it is a technical subject to enable the storage management of the tape and the recording of information about the contents of the tape as code data on the video tape itself.

[0010]

SUMMARY OF THE INVENTION The invention of claim 1 of the present application is a video tape recorder of a digital recording system for recording and reproducing first digital data obtained by encoding a television signal on a magnetic tape. A first gate signal generation circuit for generating a gate pulse during a period in which second digital data of a type different from the first digital data is inserted in a specific horizontal scanning period during vertical blanking during signal recording of The recording data generating means for generating the digital signal No. 2 and adding the error correction code to generate the recording signal, and the gate pulse for the specific horizontal scanning period during the vertical blanking during the signal reproduction of the magnetic tape. A second digital signal generating circuit using a second gate signal generating circuit and an error correction code from the signal extracted by the gate pulse of the second gate signal generating circuit. It is characterized in that it comprises a reproduction data generating means for demodulating the data.

The invention of claim 2 of the present application is a video tape recorder of a digital recording system for recording and reproducing the first digital data, which is obtained by encoding a television signal, on a magnetic tape, and is of a type different from the first digital data. Of the second digital data from the recording data generating means for generating the recording signal by adding the error correction code to the second digital data, the first memory, and the recording data generating means. A data writing circuit for writing data into the first memory, and inserting a signal held in the first memory into a specific horizontal scanning period during vertical blanking of a television signal containing the first digital data, A data insertion circuit for generating a write signal for the magnetic tape, a sync signal separation circuit for detecting a vertical sync signal and a horizontal sync signal when reproducing the magnetic tape signal, and a second A data extraction circuit that extracts a signal included in a specific horizontal scanning period from the output signal of the sync signal separation circuit by the gate pulse output from the gate signal generation circuit, and a specific signal during vertical blanking during signal reproduction of the magnetic tape. A second gate signal generation circuit for generating a gate pulse in the horizontal scanning period, a second memory for temporarily holding the output signal of the data extraction circuit, and a data read circuit for reading the signal stored in the second memory. A reproduction signal generating means for demodulating the second digital data by using an error correction code as an output signal of the data reading circuit.

[0012]

According to the inventions 1 to 4 of the present invention having the above characteristics, the recording data generating means generates the digital data of the kind different from the video signal and adds the error correction code when the signal is recorded on the magnetic tape. Generate a recording signal. The first gate signal generating circuit generates a gate pulse and inserts this digital data into a specific horizontal scanning period during vertical blanking of the television signal. The second gate signal generation circuit generates a gate pulse in a specified horizontal scanning period during vertical blanking during signal reproduction of the magnetic tape. The reproduction data generating means demodulates the digital data from the signal extracted by the gate pulse of the second gate signal generating circuit using the error correction code.

According to the inventions of claims 5 to 7 of the present application, in addition to the effects of claims 1 to 4, A: manufacturer code, model number, manufacturer number, failure history of the video tape recorder,
B: name of copyrighted video creator, recording date / time, editing history, copy permission code, C: average correction rate across all tapes, instantaneous maximum correction rate and time code at that time, D: number of continuous frames of current information, At least one item out of the number of valid data bytes, E: information unique to the user, and the error correction code can be recorded and reproduced. In this way, the user can record a lot of information, and the added value of the video tape recorder is increased.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A video tape recorder according to an embodiment of the present invention will be described with reference to the drawings. VTR of this embodiment
Since it is assumed that the television signal is digitally processed, if the error rate of the code data to be inserted is the same as that of the television signal, the insertable data in one horizontal synchronization section is the same as the video signal. Become. Therefore, the amount of code data that can be recorded increases dramatically, and if one frame (1/30 second) horizontal scanning period has a recording capacity of 768 bytes, then 768 × 30 = 23.00 Kbytes / second = Recording and playback will be possible at a data rate of 184.32 Kbit / s.

In order to realize this, means for switching the video signal and code data to be recorded and means for separating these at the time of reproduction are required. Further, a means for judging which part of the recording or reproducing is to be used is required. Further, in order to output the reproduction signal to the display unit, a means for converting the signal including the code data into a prescribed television signal waveform is also required.

The error of the video signal of a certain frame appears as a momentary video disturbance, but it is updated by the video of the next frame. On the other hand, when encoding and reproducing meaningful information as code data, an error rate lower than the error rate of the video signal is required. In addition, such data processing is usually performed by a microcomputer,
Since it requires the same processing speed as the video signal, the current signal processing speed of the microcomputer may not be sufficient. Therefore, a method is conceivable in which the same data is recorded and reproduced for several frames and the error is corrected by the majority logic, or the processing speed and the error rate are improved. As a method of reducing the error rate, a method of reducing the total number of bits in one horizontal scanning section and adding error detection and correction codes for data protection can be considered.

FIG. 1 is a block diagram showing the configuration of a signal processing unit of a video tape recorder according to an embodiment of the present invention. In the figure, an input terminal 1 is a terminal to which a reproduction signal is input. The sync signal separation circuit 2 is a circuit that separates vertical and horizontal sync signals from a television signal output during reproduction. The gate signal generation circuit 3 is a circuit that generates a gate pulse in the horizontal scanning period of a specific number based on the vertical and horizontal synchronization signals output from the synchronization signal separation circuit 1. The data extraction circuit 4 is a circuit that uses a gate pulse given from the gate signal generation circuit 3 to extract a signal in a specific horizontal scanning period from the video signal in each horizontal scanning period output from the sync separation circuit 1.

The memory 5 is a memory for temporarily storing the data signal output from the data extracting circuit 4, and its output is given to the data reading circuit 6. The system control unit 7 is a circuit that includes a microcomputer and controls the entire VTR. The system control unit 7 includes a reproduction data generation unit 7a, a recording data generation unit 7b, an encryption / decryption unit 7c, and a RAM.
7d.

The reproduction data generating means 7a is a circuit for demodulating code data from the signal extracted by the gate pulse of the gate signal generating circuit 3 using an error correction code. When an error occurs during data demodulation, the reproduction data generation means 7a stores the average correction rate, the instantaneous maximum correction rate, and the time code at that point in the RAM 7d over all tapes.
The recording data generating means 7b is a circuit that generates code data and also adds an error correction code to generate a recording signal. The encryption / decryption means 7c is a circuit that encrypts specific data of the code data at the time of recording and decrypts the specific signal included in the code data at the time of reproduction. The RAM 7d is a memory that stores the attribute data of the program of the video signal, the error correction code for some code data, and the attribute data of the video tape recorder main body.

Next, the memory 9 is a circuit for temporarily holding the code data output from the system control section 7 via the data writing circuit 8 and outputting it to the data insertion circuit 10. The data insertion circuit 10 reads the signal of the memory 9 during the period of the gate pulse output from the gate signal generation circuit 11, inserts the code data in a specific horizontal scanning period of the video signal input from the outside, and the helical track of the magnetic tape. Is a circuit for generating the recording signal of. The gate signal generation circuit 11 is
Similar to the gate signal generation circuit 4, this is a circuit for generating a gate pulse in a horizontal scanning period of a specific number. The generation positions and the number of gate pulses of the gate signal generation circuits 4 and 11 differ depending on the data amount of code data, and are instructed by the system control unit 7.

Since the processing speed of the memory (first memory) 9 is slow in order for the system control unit 7 to process the video signal in real time, the output of the system control unit 7 is once accumulated and the amount of data can be recorded. Data insertion circuit 10
It is provided for transfer to. The memory (second memory) 5 is provided to transfer data read at high speed during reproduction in accordance with the processing speed of the system controller 7.

The operation of the VTR configured as above will be described. FIG. 2 shows a video signal representing one horizontal scanning period (1H) of a standard television signal. As shown in the figure, the standard television signal is a composite waveform of the synchronizing signal and the video signal. The video signal has a signal integration in which the luminance level changes from black to white in the positive direction, and the synchronization signal has a signal component in the negative direction. Conventionally, such signals were processed in analog, but digital VTRs process these signals by A /
It is handled as D-converted digital data. When the lowest end of the sync signal is 0, the pedestal level is 7, and the white peak value is 255, the standard television signal can be represented by 8 bits.

For the timewise sampling of television signals, a method of sampling at four times the color subcarrier frequency is often adopted. Therefore, if the color subcarrier frequency is 3.579545MHz, sampling is performed at 3.579545MHz x 4 = 14.31818MHz. This digital signal is transferred and recorded. 0 if the sampling bit width is 8 bits
It means that the signal level of 256 steps up to 255 is digitized. If this parallel 8-bit signal is converted into a serial signal, it becomes 14.31818 × 8 = 114.54544 MHz.

Such high frequency recording can be performed by making the relative speed of the tape head system of the VTR extremely large, but it is actually impossible in terms of tape consumption. Therefore, in an actual VTR, two tracks are written simultaneously,
Signals are recorded by halving the frequency band, adding error correction codes, and further performing code conversion suitable for magnetic recording. The description is omitted here because it is not directly related to the present invention.

FIG. 3A is a time chart showing the positional relationship between the vertical synchronizing signal of one frame and the video signal. Figure 1
In VTR recording, a television signal as shown in FIG. 2 is input to the data insertion circuit 10. In the vertical blanking period (blanking period), the video signal is not included from 1H to 21H in the first field.
Vertical sync signal 3H as shown in (a) and (b), 6H in empty areas before and after this sync signal, teletext,
Each of 12H into which VITC (SMPTE time code) is inserted is provided.

The vertical blanking period (1H to 21H) in such a video signal has been conventionally used as an area for storing a test signal, teletext data, time code data and the like. This is the vertical sync signal and 3H before and after it
It is arranged at the vertical blanking position except for and is not limited to a specific place and is selectively used. FIG. 3B is an explanatory diagram showing the relationship between the area into which the teletext or VITC is inserted and the video signal. FIG. 3C is an explanatory diagram showing an empty area into which various code data of this embodiment is inserted. Here, the code data can be fixedly inserted 3H before and after the vertical synchronizing signal of each frame. In addition, the vertical sync signal 3H and the preceding and following 3H are combined into a total of 9H,
Inserting code data greatly increases the amount of data. In this case, vertical sync code information indicating vertical sync can be added to the first 1H portion of the vertical sync period 3H, and a data code can be inserted in the remaining area.

When recording the VTR, the recording data generating means 7b of the system controller 7 reads various code data created by software processing and stored in the RAM 7d. Next, the encryption / decryption means 7c encrypts the specific code data, rearranges the bit signals of other various code data, and adds an error correction code. The data thus generated is applied to the data writing circuit 8. This data is written in the memory 9, the system controller 7 gives an instruction to the gate signal generation circuit 11, and the code data read from the memory 9 in a specific horizontal scanning period within one frame where the moving image data is output. Is output to the data insertion circuit 10.

At the time of reproducing the VTR, the system control section 7 gives the gate signal generating circuit 3 an instruction to selectively extract a specific horizontal synchronizing period from one frame in which a moving image is reproduced. When the gate pulse is given from the gate signal generating circuit 3 to the data extracting circuit 4, the code data is extracted from the television signal reproduced by the VTR and the data is stored in the memory 5. The reproduction data generating means 7a of the system control unit 7 gives an instruction to the data reading circuit 6, fetches the data, and rearranges the bit signals and performs the error correction using the error correction code. Further, the specific code data is decrypted by the encryption / decryption means 7c.

On the other hand, the reproduced video signal is processed as a video signal when a signal having a pedestal level or higher is mixed in the horizontal scanning period 1H to 21H and output to the display unit. In order to prevent this, the video signal applied to the display unit is set to a level below the pedestal level of 1H to 21H.

The area for recording the code data is shown in FIG.
When using the entire 3H vertical synchronization period shown in (a), 1H of vertical synchronization code information is allocated, and the remaining 2H is allocated.
The digital code information may be recorded during the period. In this case, when the sync signal separation circuit 1 detects the vertical sync code information at the time of reproducing the VTR, a vertical sync signal identical to the original television signal is generated and the signal is sent to a video signal processing circuit (not shown). To do.

As described above, by providing a data area of 768 bytes as shown in FIG. 3 (d) in one horizontal scanning period having the digital code information area, the reproduction signal to which the error correction code is added is reproduced as the original signal. A demodulation circuit for demodulating into a digital video signal and a reproduction data generating means for reproducing digital code information can be shared. The data of 768 bytes is used as the following data recording area.

FIG. 3 (e) shows an example in which a 768-byte recording area is divided into a maker reserve area and a user area. Here, an error correction code is added to improve the reliability of the data. This error correction code corrects the error in both the maker reserve area and the user area to ensure the reliability of both. In this case, in order to obtain code data with higher reliability than when demodulating the video signal, it is preferable to decrease the number of bits of the code data and increase the number of bits used for the error correction code. As the data to be recorded in the maker reserve area, for example, as shown in FIG.
The manufacturer code representing the manufacturer of the VTR, the model, the manufacturing number, the manufacturing date, various set values at the time of shipment, the failure history, etc. are recorded in the RAM 7d. If the format of the data thus extracted is agreed in advance in the industry, this data can have a unified meaning throughout the industry.
It is also possible to consider the manufacturer's unique usage method.

On the other hand, the user area may be defined and used among the users, and may be uniformly defined and used for general purpose. FIG. 3 (g) shows an example of a user area used in a broadcasting station. Here, the copyright declaration, broadcast date, sponsor name, production department, director name, etc. are recorded as data. When recording multiple programs,
The frame number from the beginning of each program or the number of valid data bytes in the recording area of the code data may be recorded.

If the entire code data is encrypted, it can be used as a data area for confidential information.
In this case, the VTR serial number, various factory settings,
User's usage, such as failure history and repair history recorded by the manufacturer, a copyright declaration for the stored video, and a password (copy permission code) to read the video from the VTR with the permission of the copyright holder. Can also be considered. Further, it is possible to input the production date and time of the tape, the editing history, and the location information. By using the data area synchronized with the video in this way, the VTR can be expanded from a simple video recording device to a systematic VTR connected to a computer system.

[0035]

As described in detail above, according to the inventions of claims 1 to 4 of the present application, the first digital image signal is obtained.
It is possible to record and reproduce the second digital data indicating the attribute of the video signal together with the digital data. Therefore, by reading the code data at the time of reproduction, the user can identify various conditions at the time of recording on the videotape recorder, and the added value becomes high.

Further, according to the inventions of claims 5 to 7,
In the second digital data recording area, A: manufacturer code of video tape recorder, model number, manufacturing number, failure history, B: name of copyright holder of produced video, recording date and time, editing history, copy permission code, C: It is possible to record an average correction rate over all tapes, an instantaneous maximum correction rate and a time code at that time, D: the number of continuous frames of the current information, the number of valid data bytes, E: information unique to the user, and F: an error correction code. For this reason, it becomes impossible to copy the video without inputting the copy permission code of the copyright, and by recording the serial number of the videotape recorder, it is possible to readjust the recorded data when there is a failure, and to reproduce the cause and the cause of the failure. The effect is that the pursuit can be performed easily.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram of a television signal.

FIG. 3 is an explanatory diagram showing digital code information,
(A) is an explanatory view showing the positional relationship between the vertical synchronization signal and the video signal, (b) is an explanatory view showing the storage area of the teletext or VITC and the storage area of the video signal, (c) is the actual code data and the video Explanatory drawing showing a signal insertion area, (d) explanatory drawing showing 786-byte data inserted in one horizontal scanning period, (e) explanatory drawing showing a 768-byte usage example, (f)
Shows a usage example of the manufacturer reserve area, and (g) shows a usage example of the user area.

[Explanation of symbols]

 1 Input Terminal 2 Synchronous Signal Separation Circuit 3,11 Gate Signal Generation Circuit 4 Data Extraction Circuit 5,9 Memory 6 Data Read Circuit 7 System Control Section 7a Reproduction Data Generation Means 7b Recording Data Generation Means 7c Encryption / Decryption Means 7d RAM 8 Data writing circuit 10 Data insertion circuit

Claims (7)

[Claims] 1. A video tape recorder of a digital recording system for recording and reproducing first digital data obtained by encoding a television signal on a magnetic tape, wherein a specific horizontal scanning during vertical blanking is performed at the time of signal recording of the magnetic tape. A first gate signal generation circuit for generating a gate pulse in a period in which second digital data of a different type from the first digital data is inserted in the period; and the second digital data, and an error correction code And a second gate signal generating circuit for generating a gate pulse in a specific horizontal scanning period during vertical blanking when reproducing the signal from the magnetic tape. The second digital data is demodulated using the error correction code from the signal extracted by the gate pulse of the second gate signal generation circuit. Video tape recorder characterized by comprising: a reproduction data generating unit. 2. A video tape recorder of a digital recording system for recording and reproducing on a magnetic tape first digital data obtained by encoding a television signal, and generating second digital data of a type different from the first digital data. At the same time, a recording data generating means for generating a recording signal by adding an error correction code, a first memory, and second digital data from the recording data generating means are inputted, and this data is inputted into the first memory. And a signal written in the magnetic tape by inserting the signal held in the first memory into a specific horizontal scanning period during vertical blanking of a television signal containing first digital data. A data insertion circuit for generating an embedded signal; a sync signal separation circuit for detecting a vertical sync signal and a horizontal sync signal at the time of reproducing the signal from the magnetic tape; A data extraction circuit for extracting a signal included in a specific horizontal scanning period from an output signal of the synchronization signal separation circuit by a gate pulse output from the second gate signal generation circuit; A second gate signal generation circuit for generating a gate pulse in a specific horizontal scanning period during blanking; a second memory for temporarily holding an output signal of the data extraction circuit; and a second memory stored in the second memory. A data read circuit for reading a signal, and a reproduced signal generation means for demodulating second digital data by using an error correction code for an output signal of the data read circuit,
A video tape recorder comprising: 3. The second digital data includes a user area in which attribute data of a program of a video signal included in the first digital data is inserted, and an error in which an error correction code of the second digital data is inserted. 3. The video tape recorder according to claim 1, comprising a correction code area and a maker reserve area into which the attribute data of the video tape recorder itself is inserted. 4. The second digital data includes a user area in which attribute data of a program of a video signal included in the first digital data is inserted, and an error in which an error correction code of the second digital data is inserted. 3. The video tape recorder according to claim 1, further comprising a correction code area and a maker reserve area in which the attribute data of the video tape recorder itself is encrypted and inserted. 5. The second digital data includes: A: manufacturer code of video tape recorder, model number, serial number, failure history, B: production video copyright holder name, recording date and time, editing history, copy permission Cryptography, C: average correction rate over all tapes, instantaneous maximum correction rate and time code at that time, D: number of continuous frames of current information, number of valid data bytes, E: user-specific information, at least one item The video tape recorder according to any one of claims 1 to 3, having the error correction code. 6. The second digital data includes: A: video tape recorder manufacturer code, model number, serial number, failure history, B: production video copyright holder name, recording date and time, editing history, copy permission Encryption, C: average correction rate across all tapes, instantaneous maximum correction rate and time code at that time, D: number of continuous frames of current information, number of valid data bytes, E: user-specific information, item D of 4. The video tape recorder according to claim 1, further comprising at least one item other than item D and error correction codes thereof. 7. The recording data generating means is for generating the second digital data at a recording bit rate of the first digital data or less, and the recording data generating means is any one of claims 1 to 6. Video tape recorder described in.