JPH04243043A - Index data recording method and device for video signal - Google Patents

Abstract

PURPOSE:To prevent a reading defect by an index data reading defect arising from the deterioration of S/N arising at the time of after-recording in an azimuth recording system or the clogging of one magnetic head in a high-speed search mode, etc. CONSTITUTION:The same index data is recorded in the index part of the two adjacent tracks within the same segment and the index data recorded in the index part of the adjacent racks is read by two magnetic heads. The exact data is read from the other magnetic head even if there is the reading defect in the index data from the one magnetic head.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a VTR apparatus, and more particularly to a method and apparatus for recording and reproducing index data for a video signal in a VTR apparatus which records and reproduces video signals using an azimuth recording method.

0002

2. Description of the Related Art FIG. 3 shows a data recording format of a videotape using a segment method in which recording and reproduction are performed using helical scanning. In this recording format, one television frame is divided into four segments. The head attached to the rotating drum moves in the direction of the arrow shown. HSP indicates head switching position. A video signal is written into each segment via two magnetic heads A and B. Each segment includes a preamble PRE
To record index data (information) after
For example, an index portion ID with a length of 1H is provided. FIG. 4 shows the configuration of the index section INDEX. In this example, a data area DATA is provided after the preamble PREAMBLE, and this data area DATA consists of four blocks BLOCK1 to BLOCK4.
It is divided into

Time information is stored in BLOCK1 to BLOCK2, and various control instruction information is stored in BLOCK3 to BLOCK4. The index data includes index data that can be rewritten by the user and index data that cannot be rewritten by the user. User-rewritable index data includes:
In addition to time information, there is cue information such as a start index, end index, and skip index. In addition to time information, index data that cannot be rewritten by the user includes soft tape chapter numbers,
Contains text information such as captions.

FIG. 9(a) shows each segment SEG1 to SE
A form is shown in which different index data ID1 to ID6 are written to each adjacent track in G3. The arrow indicates the running direction of the magnetic head. 2 magnetic heads 1A
, 1B are tilted in opposite directions at predetermined azimuth angles, and are configured to record index data in the index portion ID using a tilted azimuth method. When the width of the magnetic head is Tw and the width written in each track by overlap recording is Tp (Tp is narrower than Tw), the recording width of index data rewritten by dubbing is shown in FIG. 9(b). Due to dubbing, the recording width of track A2 of segment SEG2 or track A3 of segment SEG3 is changed to (Tw
-Tp), and the width t=Tp-(Tw-Tp), which is narrower than the above-mentioned width Tp.

[0005]

Problem to be Solved by the Invention When the magnetic head of one channel is clogged in a high-speed search mode or the like, there is a problem that index data recorded on the clogged track cannot be detected. In addition, when using a magnetic head with a wide track width in consideration of compatibility and variable speed playback, the edge of the index part of the track next to the last recorded track is erased during post-recording, as shown in Figure 9(b). As mentioned above, the S/N ratio of the index data of track A2 has deteriorated, and there is a problem that the index data cannot be read out correctly.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an index data recording method in which the same index data is recorded in the index portions of two adjacent tracks constituting a segment. Further, in order to carry out the above method, the present invention provides a VTR device equipped with a magnetic head having a predetermined azimuth angle, means for writing data onto a magnetic tape via the magnetic head, and recording control means. Further, the VTR device is provided with means for reading data from the magnetic head.

[0007]

[Operation] The recording control means causes the same index data to be recorded in the corresponding index portions of two adjacent tracks of the same segment via the magnetic head. Although the recording width of the index data becomes narrow due to dubbing, even if clog occurs in one magnetic head due to high-speed search, the index data can be read normally from the other adjacent track.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block diagram of an index data rewriting device for rewriting and reading index data according to the present invention in a VTR device that records one frame divided into four segments using the azimuth recording method. The index data rewriting device includes a pinch roller 11 that runs a magnetic tape 12, a capstan roller 9, and a capstan motor 10 that rotates this capstan roller 9.
, has a tape running control system consisting of a capstan motor control circuit 8 for rotationally driving the capstan motor 10. The index data rewriting device also includes a magnetic head 1 mounted on a rotating drum, and a reproduction amplifier 3 for amplifying read data from the magnetic head 1.
The data readout system includes a data readout circuit 4 that performs predetermined data processing on the output of the reproduction amplifier 3. The read data S4 from this data read system is transferred to the microcomputer main body (MP) as a recording control device.
U) is input to 5. Furthermore, the index data rewriting device has a data writing system consisting of a data writing circuit 6 that inputs the rewriting data S6 from the MPU 5 and performs predetermined signal processing, and a recording amplifier 7 that amplifies the written data from this data writing circuit 6. are doing. A changeover switch 2 is provided between the magnetic head 1, the reproduction amplifier 3, and the recording amplifier 7, and the switch 2 is changed over by a changeover signal S2 from the MPU 5. FIG. 2 shows two-channel magnetic heads 1A, 1B, 2A, and 2B facing each other at 180 degrees as the magnetic head 1 shown in FIG.
shows. These magnetic heads have a predetermined azimuth angle. Although the index data rewriting device performs operations other than recording and reproducing index data, only the recording and reproducing of index data according to the present invention will be described below.

FIG. 3 shows the format of a magnetic tape recorded in segment format by the index data rewriting device. FIG. 4 shows an enlarged view of the index section INDEX in FIG. These contents have been described above.

FIG. 5 shows blocks BLOCK1 to BLOCK4 of the index section ID as one embodiment of the present invention.
Segments SEG1 to SEG4 and each segment SE
The correspondence relationship with adjacent tracks in G is shown.

[0011] In this embodiment, the index data is stored in adjacent tracks within the same segment, such as
The same index data, that is, time data T1 and control instruction data DATA1, are recorded in tracks A and B of segment SEG1. The same applies to other segments. This solves the above-mentioned problem, and the details will be described later.

Next, in this embodiment, the index data written in segments SEG1 and SEG2 includes time data, and control instruction data DATA1 and DATA2, which are not written by the user, include soft tape chapter numbers. , caption number, etc. On the other hand, segments SEG3 and SEG
In addition to time data, the index data written in 4 includes control instruction data UDATA1 and UDAT.
A2 includes control instruction data that the user can write, such as a "start index" that locates the beginning of a program, a "program number" that is recorded after the start index, and a "skip" that indicates not to play until the next start index. index," and "end index," which indicates the end of the software without further playback. By distinguishing between user-writable segments and non-writable segments in this way, the writing time for index data written by the user is shortened, and the details will be described later.

First, the index data rewriting operation based on a user's request will be described. In response to a command from the user to rewrite and record index data, the MPU 5 outputs a switching signal S2 to the changeover switch 2, and energizes the changeover switch 2 so that the changeover switch 2 occupies the position indicated by the solid line in the figure. Also,
The MPU 5 causes the magnetic tape 12 to run at high speed via the capstan motor control circuit 8 until the corresponding index portion is detected. When the magnetic tape 12 reaches immediately after the corresponding index portion, the high-speed running of the magnetic tape 12 is stopped. During this high-speed running period, the data readout circuit 4 reads out the index data recorded in the index section.
The MPU 5 judges the index data inputted through the data reading circuit 4 to judge whether the corresponding index portion has been reached or not, and when the corresponding index portion is reached, the high-speed running is stopped. Here, even if clog occurs due to one magnetic head, the same index data is recorded on the other track of the same segment, so the data reading circuit 4 will receive normal index data from the other magnetic head. is output. The MPU 5 controls the magnetic tape 12 to be rewound to just before the corresponding index portion based on the detected index data. During this rewinding operation, M
The PU5 outputs new index data specified by the user to the data writing circuit 6 as rewritten data S6. As a result, new index data to be written is stored in the data write circuit 6. MPU5
After confirming that the magnetic tape 12 has been rewound to just before the index position based on the information from the capstan motor control circuit 8, it issues a command to the capstan motor control circuit 8 to run the magnetic tape 12 in the forward direction. , outputs the switching signal S2 and switches the switch 2
is energized so that it is in the state shown by the broken line in the figure, and further energizes the data write circuit 6. As a result, the index data stored in the data writing circuit 6 is recorded in the corresponding index portions of two adjacent tracks A2 and B2 in the same segment.

FIG. 6 shows the recorded contents of index data during dubbing. FIG. 6 corresponds to FIG. 9 described above. In this embodiment as well, the width of the magnetic head is Tw,
The recording width of each track by dubbing is Tp. Therefore, during dubbing, the recording width t of track A2 of segment SEG2 is (Tp - (Tw
-Tp)), and the S/N of that track deteriorates. As a result, track A of segment SEG2
The index data of No. 2 may not be read accurately. However, since the same index data ID2 is also recorded in track B2 adjacent to track A2 of SEG2, even if the index data of track A2 cannot be read accurately, the index data of track B2 can be read by the magnetic head B and the data. It can be read via the readout circuit 4.

FIG. 7 shows the running trajectory of the magnetic tape when rewriting new index data when index data that can be rewritten by the user and index data that cannot be rewritten by the user are mixed and recorded in the same index section. . On the other hand, as shown in FIG. 4, this embodiment clearly distinguishes between segments in which the user can rewrite index data and segments in which the user cannot rewrite index data. FIG. 8 shows the trajectory of the magnetic tape when data is rewritten into rewritable segments. In the traveling trajectory shown in Figure 7, index data is mixed, so index data that cannot be rewritten by the user is read out and retained, and index data that can be rewritten by the user is updated for rewinding and index reading. magnetic tape running is required. In this embodiment, such a magnetic tape running operation is unnecessary, and the index writing operation time is shortened. Additionally, as shown in Figure 4, by clearly separating segments that can be rewritten by the user and segments that cannot be rewritten, it is possible to prevent index data that cannot be rewritten by the user from being destroyed due to user errors. .

[0016] When implementing the present invention, various modifications can be made in addition to those described above. In the above embodiments, the index data to be recorded is rewritten by the user, but in the present invention, the index data that cannot be rewritten by the user can also be recorded using the same index data on adjacent tracks within the same segment. Record. In addition, as a preferred embodiment, we have shown an example in which the index data is rewritten by the user by distinguishing between segment tracks that can be rewritten by the user and segments that cannot be rewritten by the user. However, even if index data is mixed, the same By recording the same index data on adjacent tracks of a segment, it is possible to solve the problem of index data read failure due to deterioration of S/N due to dubbing or index data read failure due to clog.

[0017]

As described above, according to the method of recording the same index data in advance in adjacent tracks in the same segment based on the present invention, the index data can be read by the clog of the magnetic head or by dubbing. Defects can be resolved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of an index data rewriting device of the present invention.

FIG. 2 is a diagram showing the configuration of a rotating drum head of this embodiment.

FIG. 3 is a diagram showing a format of segment-based recording data according to an embodiment of the present invention.

FIG. 4 is an enlarged view of the index section of FIG. 2;

FIG. 5 is a diagram illustrating how the index section is used in this embodiment.

FIG. 6 is a diagram showing the recorded contents of index data according to the present embodiment.

7 is a diagram illustrating a travel locus of a magnetic tape when a user writes index data using the index data rewriting device of FIG. 1 in the method of selectively using index data recording segments of the present embodiment; FIG.

FIG. 8 is a diagram showing a travel locus of a magnetic tape when writing index data in a case where index data that can be rewritten by the user and index data that cannot be rewritten by the user are mixed.

FIG. 9 is a diagram showing an index data recording state in a conventional index data recording method.

[Explanation of symbols]

1. Magnetic head, 2. Selector switch, 3.
・Reproduction amplifier, 4..data reading circuit, 5..microcomputer, 6..data writing circuit, 7..
Recording amplifier, 8... Capstan motor control circuit, 9...
・Capstan roller, 10... Capstan motor, 11... Pinch roller. Patent applicant Sony Corporation representative Patent attorney Takahisa Sato

Claims (3)

[Claims] Claim 1: A method for recording a video signal on a magnetic tape segment by segment using an azimuth recording method, comprising:
An index data recording method characterized in that the same index data is recorded in index portions of two adjacent tracks constituting a segment. 2. A VTR device that records and reproduces video signals segment by segment on a magnetic tape using an azimuth recording method, which includes a magnetic head having a predetermined azimuth angle, and writes data onto the magnetic tape via the magnetic head. and recording control means for recording the same index data in the corresponding index portions of two adjacent tracks of the same segment via the magnetic head in response to an index data rewriting command. Device. 3. A circuit connected between the magnetic head and the recording control means for reading out signals from the magnetic head, the data reading circuit cooperating with the recording control means to perform normal operation. 3. The VTR device according to claim 2, which reproduces index data.