KR19980023466A - Playback and Recording Method in Video Cassette Recorder - Google Patents

Abstract

The present invention relates to a playback and recording method in a video cassette recorder for safe recording. A playback method comprising: a first step of playing back a playback key input until there is a stop key input; And a second step of varying the duty ratio of the vis signal corresponding to the reproduced section by a predetermined value when the stop key is input, and re-recording and terminating.If there is a recorded signal in the section of the video tape to be recorded, A method for selectively recording and checking playback by changing a duty ratio of a set BIS signal. When switching to a recording mode, a section in which there is no signal recorded sequentially from the position of a loaded video tape or the preset duty A ninth step of detecting a bis signal having no ratio; A tenth step of performing recording when a section in which there is no recorded signal or a vis signal having no predetermined duty ratio is detected, and the playback is performed while reducing the duty ratio of the vis signal in the playback area during a playback by a predetermined value. In this case, by using the duty ratio of the bis signal, recording can be performed by avoiding a region that has not been played even once, so that safer recording can be performed.

Description

How to play and record on a video cassette recorder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a playback and recording method in a video cassette recorder, and more particularly to a playback and recording method in a video cassette recorder, which is recorded at the time of recording and which can prevent the program from being erased.

In general, the scheduled recording function in the video cassette recorder is a function that can reserve and record a broadcast program in advance according to a user's reservation information (eg, date, start time, end time, channel, and recording speed). It is a very useful function to automatically record the broadcast program desired by the user in the absence of the user, so that the user can play and watch the broadcast program.

In addition, while the user is watching a television broadcast program, the user may immediately switch to the recording mode to record a desired broadcast program.

On the other hand, during recording, the user should load the video tape to be recorded on the deck, and check the video recording section of the video tape and load the video tape at the start position of the video recording section.

However, when recording as described above, there is an inconvenient problem of loading the video tape at the start position of the section of the video tape where the video tape can be recorded by checking the recording state of the video tape, and the user may accidentally record the video tape. If the video tape is loaded without checking the interval, the recorded broadcast program is deleted.

On the other hand, a control signal (Control Pulse) in the video cassette recorder is recorded on the lower end of the video tape, i.e., the control track (0.75 mm), and is recorded and detected by the control head as a bipolar pulse of frequency 30 Hz.

When recording, the control signal divides the vertical sync signal of the video signal into 1/2 and then records it on the control track. During playback, the control signal is detected and compared with the reference signal 30 Hz to phase-capture the capstan motor. Phase control is made.

That is, during recording, the control signal in the form of a square wave extracted from the vertical synchronizing signal is accurately recorded on the video tape once per rotation of the cylinder, that is, every 1/30 second, and the control recorded by the control head during playback. The signal is read to control the timing of the capstan motor and rotating head cylinder that drives the videotape.

On the other hand, the VHS Index Search System (VISS) used for recording is a VHS Uniform Index (INDEX) signal, which is recorded on tape as an index signal based on converting a waveform of a normal control pulse at the beginning of recording. In other words, when recording as a bis signal, 62 control pulses having a high level and a low level of about 3: 7 are recorded, and the normal control described above with a high level and a low level of about 6: 4 behind the bis signal. The pulse is recorded.

The present invention intends to perform playback and safe recording using such a vis signal.

An object of the present invention is to devise a focus on the above-mentioned point, by using a vis signal used for recording to check whether the playback was performed during recording by varying the duty ratio of the vis signal during playback To provide a method of playing and recording in a video cassette recorder.

The playback method of the video cassette recorder according to the present invention is a method of reproducing while varying the duty ratio of a vis signal in order to check whether or not the reproduction is performed at the time of recording a variable duty ratio of the vis signal and to selectively record. Playing back until there is a stop key input; And a second step of varying the duty ratio of the bis signal corresponding to the reproduced section by a predetermined value when the stop key is input, and rewriting and terminating.

In addition, the first step determines whether there is a play key input, and if there is a play key input, stores the current position of the loaded video tape, detects a vis signal recorded before and after the current position, Storing a position of an adjacent bis signal; And performing a playback from the stored current position and determining whether there is a stop key input.

Also, the second step may include: a fifth step of stopping playback if there is a stop key input and storing a video tape position at the stop point; A sixth step of detecting distances to the Vis signals recorded before and after the position of the stop time, respectively; If the distance to the vis signal before the stop point is less than the distance to the vis signal after the stop point, the respective vis signal from the vis signal closest to the stored reproduction point to the vis signal before the stop point before the stop point A seventh step of detecting a duty ratio and reducing and changing the high level section of the vis signal by a predetermined value to rewrite the vis signal and move to the stored stop position; If the distance to the vis signal before the stop time is greater than the distance to the vis signal after the stop time, the duty ratio of each vis signal from the closest vis signal to the vis signal before the stop time is detected. And an eighth step of reducing and changing the high level section of the vis signal by a predetermined value to rewrite the vis signal and move to the position of the stored stop time, respectively.

In addition, the recording method of the video cassette recorder according to the present invention, if there is a recorded signal in the video tape section to be recorded for the purpose of selectively recording the playback by checking the presence or absence of the duty ratio of the preset vis signal change A method comprising: a ninth step of detecting a section in which there is no signal recorded sequentially or a non-signal signal having no predetermined duty ratio from a position of a loaded video tape when the recording mode is switched to a recording mode; And a tenth step of performing video recording when a section in which no pre-recorded signal or a bis signal having no predetermined duty ratio is detected is detected.

In addition, the ninth step may include: an eleventh step of detecting the first vis signal before the position of the loaded video tape and detecting the duty ratio of the detected vis signal when the recording mode is switched; If the first vis signal is not detected and the start portion of the video tape is detected, the operation proceeds to step 10. If the duty ratio of the first vis signal is variable at a preset duty ratio, the eleventh step proceeds to the tenth step. Wow; A twelfth step of determining whether a recorded signal and a vis signal are detected while driving the video tape at high speed when the duty ratio of the first vis signal is equal to a preset duty ratio; If there is a pre-recorded signal, the process proceeds to the tenth step. If the bis signal is detected, the duty ratio of the detected bis signal is detected to determine whether it is the same as the preset duty ratio. Characterized in that it comprises a step.

1 is a schematic block diagram of a video cassette recorder according to the present invention;

2 is a flowchart illustrating a playback process according to a preferred embodiment of the present invention.

3 is a flowchart illustrating a recording process according to a preferred embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

10: key input unit 20: microcomputer

30 tuner and modulator 40 signal processor

50: deck

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of a video cassette recorder according to the present invention, which includes a key input unit 10, a microcomputer 20, a tuner and a modulator 30, a signal processing unit 40, and a deck unit 50. .

In the figure, the key input unit 10 is an input means for operating a video cassette recorder, and includes a plurality of keys including a playback key, a recording key, a stop key, and the like, to provide a key signal corresponding to a user's key operation. Usually, a key signal carried on an infrared carrier wave from a remote controller is detected and output using a remote controller that can be input from a remote site.

The microcomputer 20 is a means for controlling the overall operation of the video cassette recorder. The deck unit 50 is based on the playback key signal and the recording key signal from the key input unit 10 as can be seen from the description below. ) Is selectively driven to selectively control the playback and recording modes in response to the control signal and the vis signal from the control head of the deck unit 50.

In addition, the tuner and the modulator 30 may output a broadcast signal of a channel corresponding to PLL data for channel tuning from the microcomputer 20 among a plurality of broadcast frequency signals transmitted from the broadcast system. And outputs the received video and audio signals to a predetermined channel (for example, channel 3, channel 4, etc.) and outputs them to the RF output terminal RF OUT.

On the other hand, under the control of the microcomputer 20, the signal processing unit 40 converts the broadcast signal applied from the tuner and the modulator 30 or the video and audio signals from the line input terminal LINE IN into easy-to-record signals. Processing to be applied to the deck unit 50, or the video and audio signal reproduced from the deck unit 50 is processed into a video and audio signal for easy display and applied to the line output terminal (LINE OUT), tuner and modulator 30 do.

The deck unit 50 includes a deck mechanism in which a video tape is loaded, a loading motor, a video and audio head, a head drum, a control head, a drum motor, a capstan motor, and the like, based on the control of the microcomputer 20. The video and audio signals from the signal processor 40 are recorded on the video tape, or the video and audio signals recorded on the video tape are read and output.

In particular, the deck unit 50 applies a control signal or a vis signal read from the control head to the microcomputer 20 under the control of the microcomputer 20, and transmits a video signal having a modified duty from the microcomputer 20 to the video tape. Rewrite to the corresponding control track.

Next, a detailed description will be given with reference to the flowcharts of FIGS. 2 and 3 attached to the playback and recording process according to the present invention in the video cassette recorder including the above-described configuration unit.

First, FIG. 2 is a flowchart illustrating a reproduction process according to the present invention, in which the microcomputer 20 determines whether a reproduction key signal is applied from the key input unit 10 (step 200).

At this time, when the play key signal is applied, the microcomputer 20 stores the current position of the loaded video tape using a real time counter, and controls the deck unit 50 to control the current position of the video tape. In step 202, the vis signal recorded before and after is detected while the video tape is advanced and advanced at high speed, and the position of the vis signal recorded closest to the current position of the stored video tape is stored (step 202).

At this time, the normal vis signal has a duty ratio in which the ratio between the high level and the low level is about 3: 7 as described above, and the microcomputer 20 has rising and falling edges of the signal applied from the control head of the deck unit 50. The bis signal is detected as the detection of.

Next, the microcomputer 20 controls the deck unit 50, the signal processing unit 40, the tuner and the modulator 30 to start playback from the current position of the video tape stored in the step 202 (step 204). .

At this time, when a stop key signal is applied from the key input unit 10 (step 206), the microcomputer 20 controls the deck unit 50 to stop the playback, stores the position of the video tape at the time of the playback stop, and stops the playback. The distances to the vis signals recorded before and after the viewpoint are respectively detected (step 208).

At this time, if the vis signal is not detected after the stop point, the distance until no recorded signal is replaced by the distance to the vis signal recorded after the stop point of reproduction is detected.

Next, the distance from the first detected bis signal immediately before the stop time and the first detected bis signal immediately after the stop time is compared (step 210), and the first time immediately before the stop time is compared. If the distance to the detected vis signal is smaller, all vis from the vis signal recorded closest to the reproduction start position stored in the step 202 to the vis signal before the vis signal detected immediately before the stop point Each duty ratio of the signal is detected, and the bis signal is rewritten by varying by a predetermined value from the detected duty ratio (step 212).

In detail, the bis signal duty ratio variable is a method for recognizing the microcomputer 20 that the user reproduces the region. The duty ratio is displayed at a high level 3: low level 7, which is a duty ratio of a normal bis signal every time one playback is performed. 2.9: 7.1, 2.8: 7.2 ... rewrite with reduced period of high laurel.

That is, when the duty ratio of the bis signal is about 2.9: 7.1, it is played once, and when it is about 2.8: 7.2, it is played twice.

Next, if the distance to the vis signal detected after the reproduction stop point in step 210 is smaller, the stop point is immediately started from the vis signal recorded closest to the reproduction start position stored in step 202. The duty ratios of all the vis signals up to the previously detected vis signal are respectively detected, and the bis signal is rewritten by varying by a predetermined value from the detected duty ratio (step 214).

On the other hand, after the steps 212 and 214, the microcomputer 20 controls the deck unit 50 to move to the position of the video tape at the stop point stored in the step 208 (step 216), and the playback ends. do.

On the other hand, when the playback is performed through the above-described process, the recording operation as shown in FIG. 3 is performed so that the playback is recorded in the area of the video tape which has been reproduced at least once as the duty ratio of the bis signal.

First, the microcomputer 20 determines whether there is a time when the recording key signal from the key input unit 10 is applied or when the recording key is switched to the recording mode by the reserved recording function (step 300).

At this time, when it is time to switch to the recording mode, the microcomputer 20 detects the first vis signal before the current position of the video tape loaded on the deck of the deck unit 50 by reversing the video tape at high speed, and the duty ratio thereof. Is detected (step 302).

At this time, if the Vis signal is not detected, the video tape is loaded on the deck in a state of being completely rewound to the start position, and thus the microcomputer 20 controls the deck unit 50 to switch to the recording mode from this time (step 304). ).

On the other hand, if the vis signal is detected in the step 302 and the driving of the video tape is stopped, and the duty ratio of the detected vis signal is detected, the duty ratio of the normal vis signal (3: It is determined whether the duty ratio other than 7) is a bis signal having a variable (2.9: 7.1, 2.8: 7.2 ...) (step 306).

In this case, if the duty ratio is a bis signal having a variable ratio, the broadcast signal received through the set channel is recorded at least once since it has been reproduced (step 308).

On the other hand, if the duty ratio of the vis signal detected in the step 306 is the duty ratio of the predetermined normal vis signal, the video tape is rapidly advanced again because it is not reproduced at all (step 310).

Next, the microcomputer 20 determines whether a control signal is applied (step 312), and if not applied, regards it as an empty section in which no signal is recorded, and stops the video tape being advanced at high speed and switches to the recording mode ( Step 314).

On the other hand, if the control signal is continuously applied in the step 312, it is determined whether the applied control signal is a vis signal (step 316).

At this time, if the vis signal is not detected, the process proceeds to step 310 and continues to detect the control signal and vis signal while driving the video tape forward at high speed.

On the other hand, when the bis signal is detected in step 316, the duty ratio of the detected bis signal is detected to determine whether the duty ratio of the detected bis signal is a bis signal whose duty ratio is not a duty ratio of a predetermined normal bis signal ( Step 318).

At this time, if the duty ratio of the detected vis signal is not variable, the process also proceeds to step 310 and continues to detect the control signal and the vis signal while driving the video tape forward at high speed.

On the other hand, if the duty ratio of the vis signal detected in step 318 is variable, the normal vis signal is recorded and then recording is performed (step 320).

As described above, according to the present invention, the video cassette recorder performs playback while reducing the duty ratio of the Vis signal in the playback area by a predetermined value, and does not play back at least once by using the duty ratio of the Vis signal during recording. It is possible to record more safely by avoiding the area.

Claims (5)

As a method of reproducing while varying the duty ratio of the vis signal in order to check whether or not the playback in the recording of the Vis signal (Duty) ratio variable and selectively record, If there is a play key input, playing back until there is a stop key input; And rewriting and terminating the duty ratio of the Vis signal corresponding to the reproduced section when there is a stop key input by a predetermined value. The method of claim 1, The first step is to determine whether there is a play key input, and if there is a play key input, store the current position of the loaded videotape, and detect the vis signal recorded before and after the current position and closest to the current position. Storing a position of the bis signal; And a fourth step of performing playback from the stored current position and determining whether there is a stop key input. The method of claim 2, The second step, A fifth step of stopping playback if there is a stop key input and storing the video tape position at the stop point; A sixth step of detecting distances to the Vis signals recorded before and after the position of the stop time, respectively; If the distance to the vis signal before the stop point is less than the distance to the vis signal after the stop point, the respective vis signal from the vis signal closest to the stored reproduction point to the vis signal before the stop point before the stop point A seventh step of detecting a duty ratio and reducing and changing the high level section of the vis signal by a predetermined value to rewrite the vis signal and move to the stored stop position; If the distance to the vis signal before the stop time is greater than the distance to the vis signal after the stop time, the duty ratio of each vis signal from the closest vis signal to the vis signal before the stop time is detected. And an eighth step of reducing and changing the high level section of the vis signal by a predetermined value to rewrite the vis signal and to move to the stored stop position, respectively. When there is a recorded signal in the section of the video tape to be recorded, a method for selectively recording and checking whether or not playback is performed by changing the duty ratio of a preset Vis signal. A ninth step of detecting a section in which there is no signal recorded sequentially or a non-signal signal having no predetermined duty ratio from the position of the loaded video tape when the recording mode is switched to the recording mode; And a tenth step of performing recording when a section in which there is no pre-recorded signal or a vis signal not having the preset duty ratio is detected. The method of claim 4, wherein A ninth step of detecting the first vis signal before the position of the loaded video tape upon detecting the recording mode and detecting a duty ratio of the detected vis signal; If the first vis signal is not detected and the start portion of the video tape is detected, the operation proceeds to step 10. If the duty ratio of the first vis signal is variable at a preset duty ratio, the eleventh step proceeds to the tenth step. Wow; A twelfth step of determining whether a recorded signal and a vis signal are detected while driving the video tape at high speed when the duty ratio of the first vis signal is equal to a preset duty ratio; If there is a pre-recorded signal, the process proceeds to the tenth step. If the bis signal is detected, the duty ratio of the detected bis signal is detected to determine whether it is the same as the preset duty ratio. And recording the video cassette recorder.