JPS6226683A - Magnetic tape - Google Patents

Abstract

PURPOSE:To make it possible to reproduce from any position of a tape by constituting each data signal of a start code, quantity of data, position of unit information signal on a tape, time data of starting, length or termination of the signal and discriminating data of the signal. CONSTITUTION:A magnetic tape is loaded in a magnetic recording and reproducing device, and plural recorded unit video signals are selected and reproduced. That is, an index data signal recorded in the starting end of the magnetic tape or all data signals of the magnetic tape are reproduced beforehand and stored in a memory. The data are displayed in a display unit, and desired unit video signal is selected and program number of the unit video signal is designated. Then, the magnetic tape reads data signals corresponding to the unit video signal and accesses and reproduces the unit video signal. Thus, the record can be accessed and reproduced from any position on the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape suitable for use in video cassette tapes and the like.

[Summary of the invention]

The present invention relates to a magnetic tape, in which a time code signal is recorded, and data signals respectively related to a plurality of unit information signals are recorded together with each unit information signal in the vicinity thereof, and each data signal is combined with a start code, By being composed of the following signals: data amount, position on the tape of the unit information signal, time data of the start and length or end of the unit information signal, and identification data of the unit information signal, multiple unit information signals can be generated. Any desired unit information signal can be identified and selected from a magnetic tape on which information is recorded, and can be accessed and reproduced accurately from any position on the tape.

[Conventional technology]

Conventionally, a file address, which indicates the location of each file on a magnetic tape as the number of rotations of the tape reel, is recorded at the beginning of the magnetic tape. address is stored in memory, and the magnetic tape is rotated during normal information read/write operations until the number of tape reel revolutions indicated by the file address stored in memory matches the actual number of revolutions of the tape reel. A technique for accessing a desired file by repeating the operation of sending the file at a higher speed than the feed speed was developed
It is disclosed in Publication No. 385.

[Problem that the invention seeks to solve]

However, with such conventional techniques, desired information cannot be retrieved and reproduced unless it is from the beginning of the magnetic tape, and the content of the information cannot be identified. or,
Since the file address is based on the number of rotations of the tape reel, it is difficult to accurately access the recording position of the information.

In view of this, the present invention provides a method for identifying and selecting any desired unit information signal from a magnetic tape on which a plurality of unit information signals are recorded, and accurately accessing and reproducing it from any position on the tape. This is an attempt to propose a magnetic tape that can be used.

[Means for solving problems]

In the magnetic tape according to the present invention, a time code signal is recorded, and data signals respectively related to a plurality of unit information signals are recorded together with each unit information signal in the vicinity thereof, and each data signal includes a start code, It consists of the following signals: the amount of data, the position on the tape of the unit information signal, time data of the start and length or end of the unit information signal, and identification data of the unit information signal.

[Effect]

By loading the magnetic tape according to the present invention into a magnetic reproducing device and reproducing it, any desired unit information signal recorded on the magnetic tape can be reproduced using the time code signal and data signal recorded on the magnetic tape. can be played.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a video cassette tape will be described in detail with reference to FIGS. 1 and 2.

Figure 1 shows the recording pattern of a video cassette tape.
It has a plurality of unit video signal recording sections and data signal recording sections at the side edges thereof. In each unit video signal recording section, a series of video signals are recorded so as to form an inclined track.In the data signal recording section, an SMPTE time code signal is recorded, and the user's bits are A data signal is recorded. It is also possible to record the time code signal and the data signal separately on separate tracks.

In the SMPTE time code signal, hour, minute, second, and frame (1/30 second) codes are recorded in a bi-phase manner along the entire length of the side edge of the magnetic tape, and one frame is recorded in units of 80 bits.

Each frame is provided with eight discrete user bits (binary groups) of four bits each. Therefore, in this embodiment, a data signal is inserted into this user's video.

Next, this data signal will be explained with reference to FIG. FIG. 2 shows the format of a data signal corresponding to a certain unit video signal, using n consecutive frames of an SMPTE time code signal. G1 to GB indicate the first to eighth 4-bit binary groups provided in the frame of the SMPTE time code signal. Note that the order of recording on the magnetic tape is from 01 to G8.

First, a start code is assigned to groups G8 to G5 of the first frame FR, the number of frames n (maximum 256) is assigned to groups G4 and G3, and groups G2 and G1 are assigned a start code.
Assign a checksum to.

Groups G8 and G7 of the second frame FR2 contain end program discrimination codes (whether the unit video signal is the first program, the last program, or the second or penultimate program). identification code)
and assigns the program number of the unit video signal to groups G2 and G1.

Start time data is assigned to the entire third frame. This start time data consists of 4 bits and 7 bits each for 10 hours (I
OH), 1 hour (LH), 10 minutes (IOM), 1 minute (L
M), 10 seconds (10S), 1 second (Is), 10 frames (IOF), and 1 frame (IF).

Allocate time data (long playback duration) to the entire fourth frame. This length time data consists of 4 bits of 10 hours (lOH), 1 hour (IH), and 10 minutes (IO
M), 1 minute (LM), 10 seconds (103), 1 second (Is)
, 10 frames (IOF), and 1 frame (IF).

1st to nth byte parts BY of 5th frame to nth frame
, ~BYk are assigned program identification data (identification data indicating the content of the unit video signal) expressed in alpha vents, numbers, etc. Note that end time data may also be used instead of length time data.

Then, the data of the first frame to the nth frame are
For reliable reproduction, repeat the SMPTE test, e.g. three times.
Insert into each user's bit of time code.

In addition, the entire data signal corresponding to each unit video signal is repeated three times, and the SMPTE signal at the beginning of the magnetic tape is
Insert into the user's bit of the time code signal as an index data signal. However, this can also be omitted.

Note that the time code signal into which the data signal is inserted or the separate time code signal or data signal may be provided in a part of the inclined track.

The above-described magnetic tape is loaded into a magnetic recording/reproducing apparatus (VTR), and a plurality of unit video signals recorded thereon are selected and reproduced. That is, the index data signal recorded at the beginning of the magnetic tape or all the data signals of the magnetic tape are reproduced in advance and stored in the memory. Then, display this data on the display device,
Select a desired unit video signal and specify the program number of the unit video signal. In this way, the magnetic tape reads the data signal corresponding to the unit video signal from the memory, and accesses and reproduces the unit video signal. This operation is of course possible even if the magnetic tape is in the middle. Furthermore, when transporting the magnetic tape for accessing the unit video signal, the time code data is used to ensure accurate access, and the use of the end program discrimination code allows for quick access.

Note that an audio signal (analog or PCM signal) can also be used as the unit information signal.

〔Effect of the invention〕

According to the present invention described above, it is possible to identify and select any desired unit information signal from a magnetic tape on which a plurality of unit information signals are recorded, and to accurately access and reproduce it from any position on the tape. You can get magnetic tape.

[Brief explanation of the drawing]

FIG. 1 is a pattern diagram showing a recording pattern of a magnetic tape according to the present invention, and FIG. 2 is a formant diagram showing an example of a data signal recorded on a magnetic tape according to the present invention. Make a turn in iH Ki Te~Fu Words Elementary School 1 Figure 1Fufuichi Matsu i-Figure 2 of Technique No. 100

Claims (1)

[Claims] A time code signal is recorded, and data signals respectively related to a plurality of unit information signals are recorded together with each unit information signal in the vicinity thereof, and each of the data signals includes a start code, a data amount, and the unit. 1. A magnetic tape comprising signals of the position of the information signal on the tape, time data of the start and length or end of the unit information signal, and identification data of the unit information signal.