JPH04255949A - magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To make a CM fast forwarded or fast forward reproduced at the time of reproducing and yet to perform the normal reproducing when the CM is desired to look at because a control signal is recorded even to the CM. CONSTITUTION:The device is provided with an audio multiplex discriminating circuit 1 for discriminating a movie and the CM at the time of recording, a duty ratio changeover circuit 2 for changing duty ratios of the control signal in response to an output of the above audio multiplex discriminating circuit 1, a duty ratio detecting circuit 6 for discriminating the movie and the CM by detecting the duty ratio of the control signal at the time of reproducing and a system control circuit 7 for controlling a video tape to travel in a section of the CM at a speed higher than in a section of the movie in response to an output of the duty ratio detecting circuit 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus such as a home video tape recorder, and more particularly to a magnetic recording and reproducing apparatus that fast-forwards unnecessary video portions on a video tape during reproduction.

0002

2. Description of the Related Art When a video signal recorded on a video tape is played back on a home video tape recorder, commercials (
In order to automatically fast forward unnecessary video parts such as commercial messages, etc., as disclosed in Publication No. 2-33303, the control signals of unnecessary information parts on the videotape are erased and the playback is performed. Sometimes, parts where no control signal is detected are fast-forwarded.

0003

[Problem to be Solved by the Invention] However, in the above-mentioned conventional configuration, the control signal is erased for a portion of the videotape that is considered unnecessary, so even if you wish to play back this portion later. However, there is a problem in that normal reproduction is difficult.

0004

[Means for Solving the Problems] In order to solve the above-mentioned problems, the magnetic recording and reproducing apparatus of the present invention records video signals in a direction oblique to the longitudinal direction of a video tape.
A magnetic recording and reproducing apparatus that records control signals regulating the relationship between the video signal and the video head in the longitudinal direction of a video tape, comprising an identification means for identifying necessary video and unnecessary video during recording; duty ratio switching means for switching the duty ratio of the control signal according to the output; duty ratio detection means for detecting the duty ratio of the control signal during playback to discriminate between necessary video and unnecessary video; and the duty ratio. The present invention is characterized by comprising a control means for controlling the videotape to run at a faster speed in unnecessary video sections than in necessary video sections in accordance with the output of the detection means.

[0005]

[Operation] According to the above structure, a video signal is recorded in a direction diagonal to the longitudinal direction of the video tape, and a control signal for regulating the relationship between the video signal and the video head is recorded in the longitudinal direction of the video tape. A magnetic recording and reproducing apparatus comprising: identification means for identifying necessary video and unnecessary video during recording; duty ratio switching means for switching the duty ratio of the control signal according to the output of the identification means; and the control during reproduction. a duty ratio detection means for detecting a duty ratio of a signal to discriminate between a necessary video and an unnecessary video, and an unnecessary video section having a faster speed than a necessary video section according to the output of the duty ratio detection means. and control means for controlling the videotape to run at the time of playback.
Unnecessary videos can be played back in fast forward or forward mode, and since control signals are recorded even for unnecessary videos, they can be played back normally when desired.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

[0007] With the magnetic recording/reproducing apparatus of this embodiment, for example, when recording a foreign movie program on television, the movie itself is broadcast in two languages, but the commercials (
The system uses the fact that most commercial messages are broadcast in stereo to distinguish between movies and commercials, treating only movies as necessary images and treating commercials as unnecessary images.

As shown in the block diagram of FIG. 1, the magnetic recording and reproducing apparatus includes an audio multiplexing discriminating circuit 1 (discriminating means) for outputting an identification signal for discriminating between bilingual broadcasting, monaural broadcasting, and stereoscopic broadcasting; A duty ratio switching circuit 2 (duty ratio switching means) that switches the duty ratio of the control signal according to the identification signal output from the multiplex discrimination circuit 1, and a servo circuit 3 that outputs a reference signal during recording to the duty ratio switching circuit 2. , a control head 4 that records a control signal having a predetermined duty ratio on the video tape 5 based on the output of the duty ratio switching circuit, and a control head 4 that detects the duty ratio of the reproduced control signal to distinguish between a movie and a commercial. a duty ratio detection circuit 6 (duty ratio detection means), and a system control circuit 7 (control means) that controls the videotape 5 to be fast-forwarded or fast-forwarded only during commercials in accordance with the output of the duty ratio detection circuit 6; It is mainly composed of.

The control signal is recorded in the longitudinal direction of the video tape 5 in order to regulate the relationship between the video signal and the video head (not shown), and the servo circuit 3 is operated by reproducing this control signal. By doing so, the video signal recorded obliquely to the longitudinal direction of the video tape 5 can be accurately reproduced by the video head.

Normally, the duty ratio of the control signal is set to 60%, as shown in the waveform diagram of FIG. That is, the period between the positive pulse 8 and the negative pulse 9 is 60% for one period between the positive pulses 8 and 8. In addition,
In this embodiment, the duty ratio of the control signal is 6.
The state of 0% will be referred to as logic "0".

On the other hand, when using a control signal to record an index used for cueing, etc., the duty ratio of the control signal corresponding to the portion where the index is desired to be recorded is 2 as shown in the waveform diagram of FIG.
It is set at 7.5%.

That is, the period between positive pulse 8 and negative pulse 9 is 27.5% with respect to one period between positive pulses 8 and 8. In this embodiment, a state in which the duty ratio of the control signal is 27.5% will be referred to as logic "1".

The duty ratio switching circuit 2 switches the duty ratio of the reference signal inputted from the servo circuit 3, and changes the logic of the control signal to be recorded according to the identification signal outputted from the audio multiplexing discrimination circuit 1. is switched to "0" or "1". Incidentally, since the relationship between the video signal and the video head is regulated by the positive pulse 8 in FIGS. 2 and 3, it is unrelated to the logic of the control signal.

Duty ratio switching circuit 2 of this embodiment
In this case, at the time when the identification signal of the audio multiplexing discrimination circuit 1 switches from a signal indicating bilingual broadcasting to a signal indicating stereo broadcasting, the duty ratio switching circuit 2 changes to the logic "
1" is transmitted in 3 bits. Conversely, when the identification signal switches from a signal indicating stereo broadcasting to a signal indicating bilingual broadcasting, 5 bits of logical 1" are transmitted. Furthermore, if there is no change in the identification signal, logic "0" is continuously sent out.

With the above configuration, when a foreign movie program broadcast in two languages is recorded, movie sections and commercial sections are alternately recorded on the videotape 5, as shown in FIG. In addition, the logic of the control signal at this time is such that logic "0" is continuously recorded in the section of the movie or commercial, as shown in the number string 10 in the figure corresponding to the area of the video tape 5. However, a logic ``1'' appears at the boundary between a movie and a commercial, and 3 bits of logic ``1'' are recorded at the boundary where a movie switches to a commercial, and vice versa, a logic ``1'' appears at the boundary between a movie and a commercial. 1" is recorded in 5 bits.

Therefore, when playing the videotape 5,
If the duty ratio detection circuit 6 (FIG. 1) detects the duty ratio from the control signal reproduced by the control head 4, the logic of the control signal can be known, and thereby the boundary between a movie and a commercial can be determined. . Furthermore, by counting the number of logic "1" bits, it is possible to determine whether the boundary is a boundary switching from a movie to a commercial, or a boundary switching from a commercial to a movie.

The system control circuit 7 controls the magnetic recording and reproducing apparatus according to the output of the duty ratio detecting circuit 6 so as to fast-forward or fast-forward reproduce the video tape 5 only during the CM section.

That is, as shown in the flowchart of FIG. 5, first in step 1 (hereinafter abbreviated as S1), the movie section is played back at normal playback speed, and only the commercial section is played back in fast forward or fast forward. When so-called "skip viewing" is selected, the system control circuit 7 is set to the playback mode and normal playback begins. Then, the logic of the control signal is determined by the duty ratio detection circuit 6 (Fig. 1).
Normal playback continues until 3 bits of 1" are counted (
S2). When three bits of logic "1" in the control signal are detected, this is the boundary of switching from a movie to a commercial, so the system control circuit 7 switches from the playback mode to the fast-forward mode, and fast-forward or fast-forward playback of the commercial begins (S3). Then, fast-forward or fast-forward playback continues until the duty ratio detection circuit 6 detects 5 bits of logic "1" in the control signal (S4). When 5 bits of logic "1" in the control signal are detected, this is the boundary of switching from a commercial to a movie, so the system control circuit 7 is switched from fast-forward mode to playback mode, and normal playback of the movie starts again (S5). and,
The process returns to step 2, and the above operations are repeated.

As described above, in this embodiment, movies and commercials are discriminated based on the duty ratio of the control signal, so only movies are automatically played normally without human intervention, and commercials are played back in fast forward or in a normal manner. Can be played in fast forward. Moreover, since the control signals are recorded as usual, commercials can also be played normally if necessary.

In the above embodiment, a case has been described in which only movies are treated as necessary images and commercials are treated as unnecessary images in a bilingual broadcast of a Western movie program, but the present invention is not limited to this.

[0021]

Effects of the Invention As described above, the magnetic recording and reproducing apparatus of the present invention includes identification means for identifying necessary video and unnecessary video during recording, and a duty ratio of the control signal according to the output of the identification means. a duty ratio switching means for switching the duty ratio of the control signal; a duty ratio detection means for detecting the duty ratio of the control signal during playback to discriminate between necessary video and unnecessary video; Since the section is equipped with a control means for controlling the videotape to run at a faster speed than the necessary video section, during playback,
It is possible to fast-forward or fast-forward playback only unnecessary videos, and since control signals are recorded even for unnecessary videos, it is possible to play back normally when desired.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a magnetic recording and reproducing apparatus of the present invention.

FIG. 2 is a waveform diagram of a logic “0” control signal.

FIG. 3 is a waveform diagram of a logic “1” control signal.

FIG. 4 is an explanatory diagram showing the correspondence between the arrangement of movie sections and CM sections on a videotape and the logic of control signals.

FIG. 5 is a flowchart for explaining the operation when "skipping" unnecessary videos.

[Explanation of symbols]

1 Audio multiplex discrimination circuit (discrimination means) 2 Duty ratio switching circuit (duty ratio switching means) 5 Videotape 6 Duty ratio detection circuit (duty ratio detection means)

Claims (1)

[Claims] 1. A magnetic recording and reproducing device that records a video signal in a direction diagonal to the longitudinal direction of a video tape, and records a control signal that regulates the relationship between the video signal and a video head in the longitudinal direction of the video tape. an identification means for identifying necessary video and unnecessary video during recording; a duty ratio switching means for switching the duty ratio of the control signal according to the output of the identification means; and a duty ratio switching means for switching the duty ratio of the control signal during playback. a duty ratio detection means for detecting and discriminating between necessary video and unnecessary video; and according to the output of the duty ratio detection means, the videotape is played at a faster speed for unnecessary video sections than for necessary video sections. 1. A magnetic recording and reproducing device, comprising: a control means for controlling the device to run.