JPH0312066A - Video signal reproducing device - Google Patents

Abstract

PURPOSE:To prevent the display of an unsightly picture due to generating a nonvideo signal by muting the nonvideo signal when a signal read out of a recording medium is discriminated as this nonvideo signal and outputting a signal for showing a prescribed message. CONSTITUTION:A synchronizing signal is separated by a synchronization separating circuit 17 from a luminance signal demodulated by a demodulation circuit 16, and is detected via a synchronization separating detection circuit 18 as to whether the synchronizing signal is contained or not. When the synchronizing signal is not contained in an output signal of the circuit 16, this is decided as the nonvideo signal by a CPU 20, from which a mute signal S1 is hence outputted to mute a signal from a head 10 via a change-over circuit 22, and at the same time, the prescribed message is displayed. By this method, a monitor picture can be prevented from being disturbed during reproducing access to a place recorded with the nonvideo signal, while it is clearly informed that the picture is a nonvideo picture.

Description

Detailed Description of the Invention Summary of the Invention A reproducing apparatus capable of reproducing at least a video signal from a recording medium in which a video signal and a non-video signal such as audio or data can be selectively recorded. It is determined whether the signal read from is a video signal or not, and when it is determined that it is a non-video signal, the output signal is muted and a signal representing a predetermined message is output. This prevents an unsightly image from being displayed due to reproduction of a non-video signal, and also allows you to know why the image is muted and does not appear.

In addition, in a playback device that can record video signals, when the recording mode or erase mode is set, if the signal recorded in the location (track) to be recorded or erased is a non-video signal, Preferably, recording or erasing operations are prohibited. This makes it possible to prevent valuable data from being deleted.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for a video signal recorded on a recording medium, such as a reproducing apparatus for a still video signal. Here, the reproducing device is a concept that also includes a recording/reproducing device that can record a video signal on a recording medium.

Conventional technology and its problems Typical examples of recording media for video signals include still, video, and
There is a floppy disk (hereinafter simply referred to as a video floppy). In recent years, the use of video floppies has expanded not only to recording still video signals, but also to recording audio signals (audio recording) and data recording in personal computers and word processors. These video signal records, audio records, and data records each have their own formats.

Video signals, audio signals, and data signals are recorded on a track-by-track basis, so these different types of signals can be combined into one video signal.
Sometimes they are mixed on floppies. Therefore, it is possible that a video floppy is loaded into a video signal reproducing device and tracks of non-video signals such as data and audio are played back. Even if this is not the case, a video floppy containing only data may be mistakenly connected to a video signal reproducing device.

If this video signal reproducing device does not have a data signal or audio signal reproducing function, or even if it does have it, unless it can output it as a reproduced video signal, do not give the signal output from the reproducing device to the monitor display device. However, no image appears and the screen becomes garbled.

Additionally, if the user of a playback device capable of recording video signals does not display a playback image on the monitor, it is assumed that no signal is recorded on the track being played back, and a new video signal is recorded on that track. may be recorded (or erased). If you do so, the data or audio recorded on that track will be erased.

SUMMARY OF THE INVENTION Purpose of the Invention This invention relates to a device for reproducing at least a video signal from a recording medium capable of selectively recording one video signal and a non-video signal. The purpose is to prevent disturbances in monitor images.

This invention also. It is an object of the present invention to provide a playback device that can clearly notify that a signal recorded at a location being accessed for playback is a non-video signal.

A further object of the present invention is to prevent erroneous erasure of non-video signals in a playback device capable of recording video signals.

Structure 1 of the Invention Functions and Effects The video signal reproducing device according to the present invention is a reproducing device capable of reproducing at least a video signal from a recording medium on which a video signal and other non-video signals are selectively recorded. A read head that reads signals recorded on a recording medium;
a video signal determining means for determining whether the signal read from the recording medium by the reading head is a video signal; and a video signal determining means for determining whether the signal read from the recording medium is a non-video signal. The present invention is characterized by comprising means for muting the signal output from the reproducing circuit and outputting a signal representing a predetermined message when the message is received.

According to this invention, when the signal read by the reading head is determined to be a non-video signal, the signal output from the reproduction circuit is muted and a predetermined message signal is output, so that the non-video signal is monitored. It is possible to prevent the occurrence of disturbances on the monitor screen caused by the video being sent to the computer, and a predetermined message is output, making it clear that the signal recorded at the location being accessed for playback is a non-video signal. .

In a playback device that has a function of recording a video signal on a recording medium, when the recording mode or erasing mode is set, recording or It is preferable to further provide means for prohibiting erasure.

This prevents the non-video signal from being erased by mistake.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a block diagram showing a reproducing apparatus for still video signals recorded on a video floppy disk.

The video signal playback function will be explained assuming that the recorded signal recorded on the video floppy is a still video signal (that is, it is not audio or data).

Video floppy (magnetic recording medium) (as shown)
A still video signal recorded with M modulation (hereinafter referred to as RF
The multiplied signal) is read by the magnetic head IQ and then applied to the preamplifier 11. Regenerative RF amplified by amplifier 11
The signals are applied to a low pass filter 12, a high pass filter 15 and an envelope detection circuit 19, respectively.

The low-pass filter 12 filters the color signal component (C
-This filter 1 allows only the RF multiplied signal to pass through.
A reproduced C-RF signal is extracted from 2. The reproduced C-RF signal is given to the FM demodulation circuit 13. FM demodulation circuit 13
is the color signal (C
signal). The color signal (line sequential signal) demodulated by the FM demodulation circuit I3 is supplied to the synchronization circuit 14, where it is synchronized, and then supplied to the Y/C mix circuit 21.

The high-pass filter 15 includes a luminance signal component (
It allows only the Y-RF multiplied signal to pass through.

A reproduced Y-RF signal is extracted by this high-pass filter 15. The reproduced Y-RF signal is given to the FM demodulation circuit 1B. The FM demodulation circuit 16 demodulates the input reproduced Y-RF signal into a luminance signal (Y signal) before modulation. The luminance signal demodulated by the FM demodulation circuit 16 is given to a Y/C mix circuit 21 and a sync separation circuit 17, respectively.

The Y/C mix circuit 21 mixes the input luminance signal and color signal and outputs the mixed signal as a reproduced video signal in a predetermined format. The reproduced video signal output from the Y/C mix circuit 21 is applied to the a terminal of the switching circuit 22.

A synchronizing signal is applied to the b terminal of the switching circuit 22 from a synchronizing signal generating circuit 24 . The switching circuit 22 switches between the a terminal and the b terminal based on a mute signal output from the CPU 20. When the a terminal of the switching circuit 22 is made conductive, a reproduced video signal is output, and when the b terminal is made conductive, the reproduced signal is muted.

The mute signal is output when it is determined that the signal being read by the magnetic head IO is a non-video signal.

The signal output from the switching circuit 22 is sent to the next stage mix circuit 2.
given to 3. A message signal representing a predetermined message outputted from the CPU 20 is also supplied to the mix circuit 23. The message signal is output when it is determined that the signal being read by the magnetic head IO is a non-video signal. Message signals are "not video signals."

It is used to display messages such as ``data signal'' and ``audio signal'' on the monitor, and includes a synchronization signal for displaying a single image.

Therefore, when the video signal of the video floppy is being read by the head 10, the output of the mix circuit 23 becomes a demodulated video signal.

When non-video signals other than video signals such as data signals and audio signals are being read from the video floppy, only message signals are generated.

The envelope of the reproduced RF signal is detected by an envelope detection circuit 19. When the detected envelope is at a predetermined level or higher, it is called envelope detection, and a signal indicating this is given to the CPU 20. Detection of an envelope means that some signal (video signal, data signal, or audio signal) is recorded on the track of the video floppy that is being accessed by the magnetic head IO.

On the other hand, a synchronization signal is extracted from the luminance signal demodulated by the demodulation circuit 16 in a synchronization separation circuit 17 and provided to a synchronization signal detection circuit 18 . The synchronization signal detection circuit 18 detects whether a synchronization signal is included in the output signal of the synchronization separation circuit 17.

The detection result is given to the CPU 20. Demodulation circuit 1B
The fact that the synchronization signal is included in the output signal of
This shows that the signal read by the magnetic head IO is a video signal. Further, the fact that the synchronization signal is not included indicates that the signal is a non-video signal (data signal or audio signal).

FIG. 2 is a flow chart showing the processing procedure carried out by the CPU 20, particularly the process of determining whether the read signal is a video signal, the muting process and the message signal output process that are carried out when it is a non-video signal. .

When the envelope is detected by the envelope detection circuit 19 from the signal read from the video floppy (
If YES in step 31), the track of the video floppy being accessed is not unrecorded but has some signal recorded on it, so it is checked whether the recorded signal is a video signal. To check whether a signal is a video signal, it is sufficient to detect a signal specific to a video signal. The above-mentioned synchronization signal detection circuit 18 is connected for this purpose. When the synchronizing signal is detected by the synchronizing signal detection circuit 18 (YES at step 32), the signal being read from the video floppy is a video signal, so the video signal demodulated as described above is output. As a result, the reproduced image is displayed on the monitor connected to the reproduction device.

If no envelope is detected from the signal being read from the video floppy (NO in step 31), the track is unrecorded and the changeover switch 22 is set to b.
The mute processing is performed by switching to the terminal, and a message signal for displaying the mute processing is output (step 33). As a result, "Not recorded" appears on the monitor.
The following characters are displayed. Also, if an envelope is detected from the signal being read from the video floppy (YES at step 31), but no synchronization signal is detected (NO at step 32), the track contains audio signals, data signals, etc. Since a non-video signal is being recorded, a mute signal is output to prevent a distorted image from being displayed on the monitor, the switching circuit is switched to the b terminal side, and a message is sent to indicate that the non-video signal is being accessed. A signal is output (step 34)
. For example, a message such as ``This is not a video signal'' may be displayed on the monitor.

If necessary, provide a means for determining whether a non-video signal is a data signal or an audio signal (this determination is easily possible since the formats of the data signal and audio signal are different) 1. Send the determination result as a message. It may also be displayed as .

Furthermore, in playback devices that have a video signal recording function,
It is preferable to prohibit recording or erasing when it is determined that the signal recorded on the track being accessed by the magnetic head is a non-video signal. This prevents data, audio, etc. recorded on the video floppy from being accidentally erased.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the invention. FIG. 2 is a flow chart showing the processing procedure performed by the CPU. 10...Magnetic head. 13, 18...FM demodulation circuit. 18...Synchronization signal detection circuit. 19...Envelope detection circuit. 20... CPU. 22...Switching circuit. that's all

Claims (2)

[Claims] (1) In a playback device capable of reproducing at least a video signal from a recording medium on which a video signal and other non-video signals are selectively recorded, a reading head for reading signals recorded on the recording medium; A reproduction circuit that reproduces at least a video signal among the signals read from the recording medium by the reading head, a video signal determining means for determining whether the signal read from the recording medium by the reading head is a video signal, and the recording medium. means for muting the signal output from the reproduction circuit and outputting a signal representing a predetermined message when the signal read from the medium is determined to be a non-video signal by the video signal determining means; A video signal playback device equipped with (2) In a playback device that can record video signals on a recording medium, when recording mode or erasing mode is set,
2. The video signal reproducing apparatus according to claim 1, further comprising means for prohibiting recording or erasing in response to the video signal determining means determining that the video signal is a non-video signal.