JPH0397170A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enable fast searching such as to search a desired chapter by providing plural kinds of marker signals in (n) tracks and periodically repeating to record same data in every (n) tracks. CONSTITUTION:Several kinds of marker signals are used, for example, five kinds of writing codes, the current chapter represented by P, next chapter by N, total data by T, option code by O, and time code by tc. All of these marker signals (writing codes) are provided in 30 frames and the data is repeatedly recorded with a period of 30 frames. By recording these writing codes in this arrangement on a tape, any writing codes required for fast search ing can be surely read-out from these 30 frames even when reproduction is performed at a speed faster by 7, 8, 19, or 20 times. Thus, any chapter in a recording medium which contains plural chapters can be searched at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data recording formant for a magnetic recording medium.

[Summary of the invention]

The present invention provides n(n
≧2) In addition to arranging multiple types of marker signals within a track, the same information is expressed in a cycle of n tracks, and the information of the marker signal with a cycle of n tracks is divided into the first half n/2 track and the second half. By recording in a pattern opposite to n/2 trasok, a formant magnetic recording medium capable of high-speed search is provided.

[Conventional technology]

As a magnetic recording medium for recording video signals, audio signals, etc.
For example, there is a tape used in a digital audio tape recorder (DAT) that records and reproduces audio signals using a rotating magnetic head, and the DAT tape has a structure as shown in FIG. In FIG. 8, the DAT tape AT is provided with an optional track OT inside the emission guard EC. Further, a plurality of recording tracks RT are arranged at a predetermined angle between the option tracks OT. Here, the above-mentioned Engineering Notion Guard EC has the role of a buffer band to protect data such as the recording track RT from damage to the tape due to contact between the tape and the hard disk, and also, The option track OT is provided for optional data recorded and reproduced by a fixed magnetic head. Such DAT tape A
At the same time as T travels in the direction shown by arrow TS, the recording track RT is scanned by the rotating magnetic head in the direction shown by arrow S, so that the data recorded on the recording track RT is reproduced. There is. The recording track RT also includes an audio data recording area DA as a main area where audio signals are recorded, and a subcode area SC where subcode signals such as time and address are recorded.
It can be broadly divided into A. In addition to these, AT F (Automatic
Although track following signals and the like are also recorded, illustration thereof is omitted.

Here, the subcode area SCA is composed of eight blocks, and can write information of 200 bits or more as a whole. This subcode area SCA contains not only the sampling frequency, number of channels, track pitch, and other essential items for audio data playback, but also the signals necessary for high-speed searches such as song number and performance time. recorded. Therefore, with the DAT, it is possible to quickly locate the beginning of a plurality of songs recorded on a tape.

By the way, in contrast to the above-mentioned DAT tape that handles audio signals, there is a video tape as a magnetic recording medium used for recording and reproducing video and audio signals.

An example of this videotape is the so-called 8mm videotape, which has a standardized standard.The structure of the 8mm videotape is as shown in FIG. 9.

In the 8mm video tape VT shown in FIG. 9, the recording track RT sandwiched between the obstruction track OT and the guide band CB has a video data recording area VD for recording video signals for 1 field and an APC audio signal for recording. It consists of an audio data recording area APCM. 8mm video tape VT like this is arrow TS
The rotary magnetic head scans the recording track RT in the direction indicated by arrow S, thereby reproducing the data recorded on the recording track RT.

Also, a marker area MA is arranged between the video data recording area VD and the audio data recording area A P C'M, and a cue signal is written in the marker area MA in advance. Marker area M
By searching for A, a predetermined position on the tape was found. That is, during a high-speed search, a predetermined position on the tape is found by reading out the first found recording track having the marker area MA in which the cue signal is written. Note that this marker area MA can be expanded, and it has also been proposed that address information for a predetermined position on the tape be written in this expanded area. Furthermore, the overall recording format of video software such as 8 mm videotape is as shown in FIG.

That is, in FIG. 10, the videotape VT has leader tables rtl and rt2 arranged at both ends in the longitudinal direction.
In order from the leader tape rtl, the unrecorded part nrl, 1 minute black hundred face li for lead-in, (chapter 00)
, a program portion pr (chapter 01 to chapter may), which is a portion where video signals, audio signals, etc. are recorded;
Kuromomen e for over 1 minute for lead-out. t (Chabuta EF), unrecorded part nr2, leader tape rt
It is configured as shown in 2.

[Problem to be Solved by the Invention] When there is a position to cue on an 8mm videotape having the recording format as described above, in other words, when a tape is composed of a plurality of chapters as shown in Fig. 10. When searching for the beginning of an arbitrary chapuku from within the tape, in the conventional method, as mentioned above, the marker area MA in which a predetermined signal is written is searched in advance. Marker area M with a signal written on it
In the case where there are a plurality of chapters having A, and it is necessary to find only an arbitrary chapter among them, it takes time.

That is, in the conventional method, in order to search sequentially from the first cue marker area MA when the tape is inserted (chapters are played back in the order in which the cue marker area MA is discovered), any of the above arbitrary chapters is searched. It took a long time to search. Also, for example, it was impossible to randomly access multiple chapters. For this reason, the marker area MA of the 8mm videotape is expanded, and data (address information, etc.) for high-speed search processing such as the above-mentioned DAT tape cueing etc. is recorded in this expanded area. can also be considered. but,
While the subcode area SCA can record data of 200 bits or more, the extended 'vJ area of the marker area MA can only have a capacity of about 40 bits. Therefore, all of the high-speed search data cannot be recorded in one marker area MA.

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium having a format that allows high-speed search for any chapter in a magnetic recording medium in which a plurality of chapters exist. The purpose is to

[Means to solve the problem]

The magnetic recording medium of the present invention has been proposed to achieve the above-mentioned object, and in a magnetic recording medium in which a video signal and a marker signal are recorded at different positions on the same track, the marker signal Prepare multiple types of markers (for example, 5 types of writing codes shown in Table 1), and write all types of markers within n (n≧2) tracks (n/2 frames), for example, n = 60 tracks (30 frames). In addition to arranging signals (writing codes), the same information is expressed at a cycle of 60 tracks (30 frames). Further, the magnetic recording medium of the present invention stores information of a marker signal (write code) with a period of 60 tracks (30 frames).
The first half n/2 tracks and the second half n/2 tracks are recorded as reverse patterns.

[Effect]

According to the present invention, all types of marker signals within n tracks can be read during high-speed search.

(Example) Hereinafter, an example to which the present invention is applied will be described with reference to the drawings.

FIG. 1 schematically shows a specific example of the data format of the magnetic recording medium according to the embodiment. In addition, in the example shown in Figure 1, a standard television signal (so-called NTSC signal) is handled.
Record one field worth of video signal on the l recording track,
n (n≧2) tracks are set to n = 60 tracks (30 frames). It also shows the passage of time in seconds.

In FIG. 1, first, multiple types of marker signals are prepared. For example, as the marker signal, the current chapter P, the next chapter N, as shown in Table 1 described later,
Five types of writing codes are prepared: total data T, option code O, and time code tc. At this time, in FIG. 1, all types of marker signals (write codes) are arranged in the 3o frames, and the same information is expressed in the 30 frame period. In addition, the information of the marker signal (write code) with a period of 30 frames is stored in each frame (0
The pattern is reversed between each field of frames 14 to 14) and each field of each frame of the latter half (frames 15 to 29).

By the way, during normal 1x speed playback, the rotating magnetic hand traces all the recording tracks, so if you write the write code as described above to each recording track, you can control the placement of the write code at the time of writing. All written codes can be read with a rotating magnetic field without any consideration. However, in the case of constant double speed playback, especially in the case of highly accurate constant double speed playback, the rotating magnetic head does not trace all the recording tracks, but skips over the recording tracks every predetermined number of times corresponding to the constant double speed playback. Since the code is to be reproduced, the write code written in the skipped recording track will not be reproduced. In particular, in the case of even-numbered double speed playback, if the field you start reading is an odd field, only the odd fields will be read forever, and conversely, if the field you start reading is an even field, only the even fields will be read. Therefore, it is not possible to read all types of writing codes. For this reason, this embodiment adopts the arrangement shown in FIG. 1.

Here, the marker signal has a configuration as shown in FIG. 2.

That is, in FIG. 2, the marker signal ma is 1
．． 2 6 H header (search signal SS), 0.
2 4 H data dm is being used. In addition, H
indicates the signal recording length of the video signal to be recorded for 1,000 periods. The above search signal SS is applied to each field for 10 seconds (
Index I of NTSC, SP) "O'" (2.9MHz). Once written, it can be used for searches, scans, etc. In addition, the index IBM is erased at "1", and the marker signal ms is no longer used for searching, etc. The data dm includes the code start marker force (start mark flock) sm,
1 block 8 bits 5 bronc data block W
DO~WD4 (40 bints in total), CRCC block, code end marker (end mark block) e
It consists of 8 broncs of m. Here, each data of the write code shown in Table 1 is written to the data block WDO to WD4.

In Table 1, the mode numbers of each write code are: time code Lc is mode 1, option code O is mode 16, current chapter P is mode 17, NEXT chapter N is mode 18, total data T is mode 19. has been done. Also, time code [C is mode. Time. minutes,
The option code O indicating that the tape is recorded in video software format is undefined, and the current chapter P indicating the current chapter number and the elapsed time within that chapter is the mode and chapter number. ,Time,
It consists of minutes and seconds. Furthermore, the next chapter number and the next chapter N, which indicates the time until the next chapter, are composed of mode, chapter number, minutes, seconds, and 1 frame.
The total data T indicating the total number of chabutas and the total time is the mode. It consists of the number of chapters, hours, minutes, and seconds. Each data of each of the above write codes is written into data blocks WDO to WD4 in FIG. 2 according to the mode number. Furthermore, each word of each write code in Table 1 is shown in hexadecimal. Here, the arrangement of the write codes shown in FIG. 1 is shown in Tables 2 and 3. Table 2 shows even seconds, and Table 3 shows odd seconds.

Table 2 (blank below) Table 3 First, in Table 2 showing even seconds, time codes tc are written in the fields of even frames 0 to 14 and frames 15 to 29. In frames 0 to 14, option code O is placed in the even field of the first frame of the odd numbered frame, and total data T is placed in the odd numbered field.
is written, and the current chapter P is written in the even field of the frames other than the first odd frame, and the next chapter N is written in the odd field. Also, 15
In the ~29th frame, write total data T in the even field of the 15th frame, write option code ○ in the odd field, and write NEXT chapter N in the even field of other frames other than the 15th odd numbered frame.
, and the current chapter P is written in the odd field.

Next, in Table 3 showing odd-numbered seconds, time codes tc are written in the odd-numbered frame fields of frames 0-14 and frames 15-29. In frames 0 to I4, option code O is placed in the even field of the 0th frame of even frames, and total data T is placed in the odd field.
is written, and the current chapter P is written in the even fields of the frames other than the Oth frame of the even frames, and the next chapter N is written in the odd fields. Also, 15
In the ~29th frame, total data T is written in the even field of the 16th frame, option code O is written in the odd field, NEXT chapter N is written in the even field of other frames other than the 16th frame, and the current chapter is written in the odd field. Write P.

With the arrangement of Tables 2 and 3, the writing code is
It is written onto the tape as shown in the figure. That is, by writing each write code on the tape in the arrangement as shown in FIG. 1, during the double speed playback described above, for example, seven times speed playback as shown in FIGS. 3 to 6. 8x speed playback. Even in 19x or 20x playback, it is possible to read the written code necessary for high-speed search within 30 frames. In addition, in Figures 3 to 6,
Option code O and total data T have not been read, but since these two write codes do not change throughout the tape, they can be read during normal 1x speed playback.

Further, the shaded areas in FIGS. 3 to 6 indicate fields that can be read by the rotating magnetic head.

For example, in the case of 7x speed playback shown in FIG. 3, frames 0 to 14 (first half frames). For both the 15th to 29th frames (second half frames), the current chapter P, NEXT chapter N, and time code tc, which are necessary when performing a high-speed search, can be read with a rotating magnetic hand. In addition, in the case of 8x playback shown in Fig. 4, only the time code tc is read in the odd seconds of frames 0 to 14 (first half frame), and only the current chapter P is read in the even seconds, and in this first half frame, the NEXT chapter is read. N has not been bribed. However, in the 15th to 29th frames (second half frames), the write code pattern is reversed in the fields of each frame, so only the time code tcL is read in even seconds, but the NEXT chapter N is read in odd seconds. is possible. Therefore, even at even speeds such as 8x playback, it is possible to read the necessary written code without fail. Similarly, in the 19x playback shown in FIG. 4, the time code tc and NEXT chapter N can be read in odd-numbered seconds, and the time code Lc and current chapter P can be read in even-numbered seconds. Furthermore, in the 20x playback shown in FIG. 6, the Quim code tc can be read in even seconds, and the current chabuta P and NEκT chapter N can be read in odd seconds. As described above, in this embodiment, the time code tc, current chapter P, and NEX chapter N necessary for high-speed search are used even in odd-numbered speed playback or even-numbered speed playback.
and can be read without fail.

In addition, in this example, in the re-habitation mode of 30x playback or higher,
There are cases where the writing code necessary for the above-mentioned high-speed search cannot be read (for example, 30.60, 62, 66.70).
(double speed playback). However, in such a high-speed playback mode, for example, there is no practical difference between 29x playback and 30x playback, so if you avoid this 30x playback and use 29x playback (or 31x playback), there will be no problem. Furthermore, if the speed is 60 times or higher, the reading capacity of the video equipment itself may be exceeded, so it is not considered to be actually used. Furthermore, when the speed is not constant with high precision, such as during fast-forward playback or rewind playback, the fields to be played are shifted, so it is important to be able to reset all written codes. need not be considered.

FIG. 7 shows the positional relationship between the video data recording area and the audio data recording area on the marker signal recording track described above.

In FIG. 7, the marker signal ma is recorded at the connection point O between the video data recording area VD and the audio data recording area APCM.

The audio data recording area APCM has a postampule pa of 3.0H from the connection point O, and the video data recording area VD has a VP guard vp of 3.8H from the connection point O. Further, the magnetic signal ma is generated from the contact point between the audio PCM signal recording area apcm of the audio data recording area VD and the post ampoule pa. 6
5H and from the contact point between the video signal recording area vd of the video data recording area VD and the VP guard vp. 6
It has a 1.5H area at the 5H position,
Also, the above connection point 0 is 0. It is located at a 3 5 H shift.

Index ■ of this marker signal ma. is the second
As shown in the figure, writing/erasing is possible, and erasing is performed within an erasing area ea of 2.8H centered on the connection point O.

In addition, the above-mentioned n=60} rank (30 frames) is
It goes without saying that the number is not limited to n-60, and that various numbers can be used without changing the gist of the present invention.

〔Effect of the invention〕

In the magnetic recording medium of the present invention, n tracks (n/2
A plurality of types of marker signals are arranged in a frame) and represent the same information in n track periods. For example, the information of the marker signal in the n track period is
By recording in a format with a reverse pattern between the track and the latter n/2 tracks, it becomes possible to perform high-speed searches such as finding the beginning of any chapter on a magnetic recording medium where multiple chapters exist. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a specific example of a data format according to an embodiment of the present invention, FIG. 2 is a diagram showing details of the structure of a marker signal, and FIG. 3 is a diagram for explaining fields read during 7x speed playback. Figure 4 is a diagram to explain the fields read during 8x speed playback, Figure 5 is a diagram to explain the fields read during 19x playback, and Figure 6 is a diagram to explain the fields read during 20x playback. FIG. 7 is a diagram showing the position of the marker signal, FIG. 8 is a schematic plan view of the DAT tape, and FIG. 9 is a diagram showing the position of the marker signal.
FIG. 10 is a schematic plan view of an 8 mm video tape and shows the basic structure of an 8 mm video tape.

Claims (2)

[Claims] (1) In a magnetic recording medium in which a video signal and a marker signal are recorded at different positions on the same track, prepare multiple types of the above marker signals and arrange all types of marker signals within n (n≧2) tracks. and a magnetic recording medium characterized in that the same information is expressed at the cycle of the n tracks. (2) The magnetic recording medium according to claim 1, wherein the information of the marker signal having a period of n tracks is recorded as reverse patterns in the first n/2 tracks and the latter n/2 tracks.