JPH0748293B2 - Code recorder and code converter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a code recording device for recording a code for recording time information of a video signal on a magnetic tape.

[Prior Art] Conventionally, for recording time information on a video tape, in a commercial VTR, a so-called absolute time is displayed on a cue track or a video track on the video tape.
SMPTE code or vertical blanking time code (V
ITC) was recorded in frame units.

On the other hand, VTRs of VHS (trademark) and S-VHS (trademark) employ the CTL coding method. There are two types of codes using the CTL coding method, index codes and address codes, which are used respectively for finding the beginning of a program and finding the absolute position from the recording start portion on a magnetic tape.

[Problems to be Solved by the Invention] However, in any of the above-mentioned methods, there is no particular provision for managing the magnetic tape in absolute time, such as the SMPTE code and VITC used in a commercial VTR. In order to control the tape position on a frame-by-frame basis, the address code is treated as time data and recorded on the magnetic tape at regular intervals (for example, every 1 minute).
It is necessary to reset the frame counter at the position where the code is read, and then count the control pulse (CTL pulse) to manage the frame. However, with this method, it takes time to read the code, and one of the three address data in the address code is read.
If even one is lost, there was a problem that the position where the code was read was shifted. Such a problem is that it takes time to read the code even when VASS is made to correspond to the time code.

In addition, the above CTL coding method uses 1 per frame.
Since it records bits, SMPTE time code of 80 bits per frame and VIT of 90 bits per frame
There is a problem that C cannot be recorded in the code format as it is.

The present invention has been made to solve the problems in the conventional example as described above. In the CTL coding method, a time code is newly set as means for recording time data, and a system using this sets a time code. An object of the present invention is to provide a code recording device capable of performing real-time management and a code converter used for the same.

[Means for Solving the Problems] A first code recording apparatus according to the present invention is a code recording apparatus for recording a code on a control track of a magnetic tape as a change in a duty ratio of a control signal, and each frame of a television signal. A code reader for receiving the first code input indicating different time information, which is assigned to each of the televisions, and detecting the time information; and for each frame of the television signal based on the detection time information from the code reader. Of the first code of the first code of a predetermined frame for each of a plurality of consecutive frames
A code recording device comprising means for generating a second code indicating the same time as the time indicated by the code and outputting the second code over the plurality of consecutive frames from the predetermined frame. is there.

A second code recording device according to the present invention is a code recording device for recording a code by superimposing the code on a cue track or a video track of a magnetic tape in a vertical blanking of a television signal, wherein the television signal is continuous. A code reader that receives the second code input indicating the same time information over a plurality of frames and detects the time information, and 1 of the television signal based on the detected time information from the code reader.
A code recording device, comprising: means for generating a first code indicating different time information for each frame and sequentially outputting the first code from a frame synchronized with a predetermined frame of the plurality of frames. .

In addition, according to the present invention, code conversion devices used for the first and second code recording devices are provided, respectively.

[Operation] In the first code recording apparatus according to the present invention, the time information is received by receiving the first code input indicating different time information, which is assigned to each frame of the television signal by the code reader. Detect and second
Of the first code for each frame of the television signal based on the detection time information from the code reader, the same as the time indicated by the first code of a predetermined frame for each of a plurality of consecutive frames. The second code indicating the time is generated, the second code is output over a plurality of consecutive frames from the predetermined frame, and the second code is recorded on the control track as a change in the duty ratio of the control signal.

Further, according to the second code recording apparatus of the present invention, the code reader receives the first code input indicating the same time information over a plurality of consecutive frames of the television signal, detects the time information, and detects the second time. The means for outputting a code generates a second code indicating different time information for each frame of the television signal based on the detected time information from the code reader, and sequentially outputs a second code from a plurality of frames synchronized with a predetermined frame. Code is output, and the second code is recorded on the cue track or the video track by being superimposed in the vertical blanking of the television signal.

[Examples] Examples of the present invention will be described in detail below. First, a time code (hereinafter abbreviated as CTLTC) is set as a means for newly recording time data in the CTL coding method. This CTLTC consists of 11-bit header and 4
Bit BCD 4-digit user data, BCD 6-digit time code data, and 4-bit checksum are added to make a total of 50 bits. Further, in the case of a video signal with a period of 30 frames such as NTSC, a total of 60 bits or 58 bits is formed by adding 10 bits or 8 dummy bits after the checksum.

FIG. 1 shows a configuration example of a signal format of CTLC used by the device of the present invention. In the figure, H is a header consisting of 11 fixed bits, U is a 16-bit (4-bit BCD 4-digit) user bit for the user to record a program number using an input device such as a keyboard, and T is currently 19-bit (BCD 6-digit) time information data that represents time in hours, minutes, and seconds. The first 2 bits are the 10s digit of the "hour", and the 4th bits are the 1s digit of the "hour". And the next 3
The 10th digit of the "minute" in bits, the 1s digit of the "minute" in the next 4 bits, the 10s digit of the "second" in the next 3 bits, and the "second" in the next 3 bits Indicates the ones digit of the. Also, S indicates a 4-bit checksum, D indicates an 8 or 10 dummy bit, and the first 1 bit identifies the correction mode or the non-correction mode. When "0", the non-correction mode (non-drop mode Frame mode) does not correct the time lag,
As a correction mode (drop frame mode) for "1", 8 bits of dummy bits (bits including drop frame bits) at 00 seconds of each minute except 0, 10, 20, 30, 40, and 50 minutes Number). As described above, one data block consisting of 60 bits corresponds to about 2 seconds for a video signal of 29.97 frames / second such as NTSC. Therefore, the digit of ones digit of "second" of the time information data T. Is 0, 2, 4, 6, 8 seconds 5
3 bits are enough because only one value needs to be shown.
For NTSC color signals as described above, the number of frames is nominally 2
Since it is 9.97 frames / second, the step of the time code slightly shifts from the real time. To correct this time shift, the bit length of the dummy bit depends on the number of bits at every predetermined time length. It is designed to be corrected. On the other hand, in the case of a video signal of 25 frames / sec like PAL, 50 bits corresponds to 2 seconds, so the dummy bit is unnecessary. Further, in the figure, the reference position indicates the position in real time indicated by the time code data immediately before it.

Therefore, according to the above signal format, it is possible to correct the time shift by changing the data length in one data block without skipping the time code data, and the data in the time code data is PAL or SECAM. It can be applied as it is to a video signal of 25 frames / sec.

FIG. 2 illustrates the first code recording device of the present invention, and is a system configuration for reading the SMPTE time code recorded in the master VTR during reproduction and recording the CTLTC generated in synchronization with the SMPTE time code in the slave VTR. The figure is shown. Master VTR1
When is set to playback mode, the SMPTE time code signal recorded on the magnetic tape is output from the time code output terminal TCOUT, and is input to the input terminal TCIN of the time code reader (hereinafter also referred to as "SMPTE time code reader") 2. Supplied.

The time code reader 2 has the configuration shown in FIG. 3, extracts a clock signal from the input time code signal in the clock generator 2a (generates a clock), and reads the input signal into the synchronous word shift register 2b at this clock. Then, the sync detection circuit 2c detects the sync part, identifies the reading direction of FWD / REV by the bit information after the sync detection, gives the reading direction signal to the data shift register 2d, and reads the input signal to this data shift register 2d. Let 80 clocks of the input signal are measured by the counter 2e and compared by the timing comparison circuit 2f with the synchronization signal, and when the data group is correct, the data read timing pulse is given to the buffer shift register 2g, and at this time the buffer shift The 64-bit or 32-bit time code stored in the register 2g is output. Further, this time code reader 2 has a built-in data bus buffer 2h and reads the time code value (hour, minute,
Seconds, frames; corresponding to the first code).
This held data can be read externally via the data bus by setting the read status Read to low, and the data can be read after the data set status INTR indicating that a new time code has been read becomes high. By reading, the same data is prevented from being repeatedly read. This data set status INTR is reset to low by setting read status Read to low.

The presettable time code generator 3 for reading the data held by the time code reader 2 via the data bus has a time code counter (including hours, minutes and seconds),
This time code counter is configured so that the count value becomes the same as the value read from the time code reader 2.

In this way, the time code value read from the master VTR 1 is synchronously generated by the presettable time code generator 3. When the second and frame data of the generated time code value is 0 seconds 10 frames, 2 seconds 10 frames, 4 seconds 10 frames, 6 seconds 10 frames, 8 seconds 10 frames, a write start signal to the CTL data output circuit 4 and Time code value for writing (When adding 2 seconds to the time code value at that time,
Only the minute and second data are sent, and the frame data address is not recorded) (Note that the above 10 frames correspond to 10 dummy bits and are unnecessary when the frame frequency is 25 Hz like PAL, and 0 seconds ( 0 frame), 2 seconds,
Send the time code for writing at 4 seconds).

Upon receiving the write start signal, the CTL data output circuit 4 starts data output from the first bit of the header in the next frame. Here, the time code value to be output is the data (corresponding to the second code) sent from the presettable time code generator 3 immediately before.

In this way, the output CTL data is the slave VTR5
And used as a variable duty signal of the recording control pulse.

That is, in the embodiment shown in FIG. 2, the address value (time information) of the first code in which different first address values (time information) are assigned to the respective television frames by the SMPTE time code reader 2 And a second code having a second address value (time information) having the same value as a part of the first address value is generated by the presettable time code generator 3 based on the detected value. The first code for each frame of the John signal is converted into the second code for each of a plurality of frames, and the CTL
The code is recorded on the control track as a change in the duty ratio of the control signal via the data output circuit 4.

The SMPTE recorded on the master tape by the above operation
The time code and the time code recorded by CTL coding on the tape of the slave VTR5 match on a frame-by-frame basis, and the operation by time code is possible on the slave VTR5 side, and the data can be used on the master side as is.

If you use VITC instead of SMPTE time code, the dubbing system from SMPTE time code to CTLTC described above can convert SMPTE time code reader 2 to VITC reader and change the TC terminal connection to VIDEO connection. It is possible.

Next, FIG. 4 illustrates the second code recording device of the present invention. The CTLTC recorded in the master VTR6 is read at the time of reproduction, and the SMPTE time code generated in synchronization therewith is recorded in the slave VTR9. The block diagram of a system is shown. When the master VTR 6 is set to the reproduction mode, the CTL pulse output from the CTL pulse output terminal is supplied to the CTL pulse input terminal of the CTLTC decoder 7.

The CTLTC decoder 7 has the configuration shown in FIG. 5, and the inputted CTL pulse is discriminated in its duty ratio by the CTL duty discrimination circuit 7a, and the CTL of “0” and “1” is obtained.
The data is extracted and supplied to the time code data extraction circuit 7b together with the CTL clock. The time code data extraction circuit 7b latches the supplied CTL data, performs header detection to extract the time code data, and further drops frame bits in the latched data (see FIG. 1).
By checking, the drop frame bit discrimination status is output, and the latched data is supplied to the data buffer 7c to enable external reading. The data buffer 7c sets the data set status INTR to high level when data is set, outputs the time code data to the parallel data output when low level is applied to the data output enable input (Read), and sets the data set status INTR to Reset to low level.

The presettable time code generator 8 which receives the output of the CTLTC decoder 7 has the configuration shown in FIG. 6, and when it receives data from the CTLTC decoder 7 via the time code read control circuit 8a, it outputs it to the time code counter 8b. Give it as a preset value to start the counting operation.
The counter 8b counts up every frame (one time code is assigned to one frame),
The coefficient value (time code data) is converted into a serial signal by the serialization circuit 8c and output to the time code output terminal TCOUT in synchronization with the external synchronization signal EXTSYNC. This output is
In Fig. 4, time code input terminal of slave VTR9
It is supplied to TCIN and recorded on the time code track of the slave tape in recording mode.

That is, according to the embodiment of FIG. 4, the CTLTC decoder 7
The second address in which different address values (time information) are assigned to a plurality of frames of the television signal by the
The address value (time information) of the code is detected, and the first address value (time information) whose part is the same as the second address value (time information) based on the detected value by the presettable time code generator 8. A first code having a plurality of frames of the television signal is converted into a first code of each frame and the code is vertically blanked on a cue track or a video track. It is recorded by superimposing it inside.

In order to make the above-mentioned CTLTC-to-SMPTE time code conversion dubbing system compatible with VITC, the serial signal in the presettable time code generator 8 can be output in the VITC format as shown in FIG. As shown, an encoder circuit 8d and an inserter 8e for inserting the code signal into the video signal are required to be added.

[Effects of the Invention] As described above, according to the first or second code recording apparatus and the code converter used for the same of the present invention, the time code for each frame of the video signal and the one for every plural frames are provided.
Since the system that records the time code obtained by converting with the CTL time code is configured, it is possible to manage the real time in the CTL coding and record the continuous time code for each frame. A recording device with a low bit rate. It is possible to record the time code thinned out every several frames, and convert the code between the time code in the CTL coding method and the SMPTE time code or VITC to record the coincident real-time code in frame units.

[Brief description of drawings]

FIG. 1 is a signal format diagram of a time code in a CTL coding system set for use in the device of the present invention, FIG. 2 is a configuration diagram of a first code recording device according to the present invention, and FIG. 3 is a diagram of FIG. FIG. 4 is an internal configuration diagram of the SMPTE time code reader 2, FIG. 4 is a configuration diagram of a second code recording device according to the present invention, and FIGS. 5 and 6 are respectively the CTLTC decoder 7 and presetter time code generation of FIG. It is an internal block diagram of the container 8. 1,6 …… Master VTR, 2 …… SMPTE time coder, 3,8 ……
Presettable time code generator, 4 ... CTL data output circuit, 5, 9 ... Slave VTR, 7 ... CTLTC decoder.

Claims (4)

[Claims] 1. A code recording apparatus for recording a code on a control track of a magnetic tape as a change in a duty ratio of a control signal, the first code indicating different time information assigned to each frame of a television signal. A code reader that receives the code input to detect the time information, and a predetermined code for each of a plurality of consecutive frames of the first code for each frame of the television signal based on the detection time information from the code reader. The first of the frame
Second indicating the same time as the time indicated by the code
And a means for generating the code and outputting the second code over the plurality of consecutive frames from the predetermined frame. 2. A code recording apparatus for recording a code on a cue track or a video track of a magnetic tape by superimposing it within vertical blanking of a television signal, wherein the same time information is recorded over a plurality of consecutive frames of the television signal. A code reader that receives the second code input shown and detects the time information, and a first code that shows different time information for each frame of the television signal based on the detected time information from the code reader. The code recording apparatus further comprises means for sequentially outputting the first code from a frame synchronized with a predetermined frame of the plurality of frames. 3. A code reader which receives different first code inputs indicating time information, which are assigned to respective frames of a television signal, and which detects the time information, and a detection time from the code reader. Of the first code for each frame of the television signal based on information, the first code for a predetermined frame for each of a plurality of consecutive frames.
A code converter comprising means for generating a second code indicating the same time as the time indicated by the code and outputting the second code over the plurality of consecutive frames from the predetermined frame. 4. A code reader for receiving the second code input indicating the same time information over a plurality of consecutive frames of a television signal to detect the time information, and the television based on the detected time information from the code reader. A code converter comprising means for generating a first code indicating different time information for each frame of the John signal and sequentially outputting the first code from a frame synchronized with a predetermined frame of the plurality of frames.