JPH02226893A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent rainbow noise at reproduction of overwrite portion by interrupting a chroma signal for a prescribed time after recording stop command and recording only a luminance signal so as to simplify the detection of the end of recording area of an old scene at consecutive shot. CONSTITUTION:The device is provided with an input terminal 1 for a video signal, an input terminal 2 for a control signal, an OSD(ON SCREEN DISPLAY) 3, a luminance signal (Y)/chroma signal (C) separator 4, a recording luminance signal processing circuit 5, a recording chroma signal processing circuit 6, a switch 7 a Y/C mixer 8 and an output terminal 9. Since only the luminance signal Y subjected to FM modulation for a prescribed time together with a recording stop command is used as the recording signal, the recording area having only the luminance signal Y from the end of the recording area of the scene is provided. Thus, the end of the recording area of an old scene is simply detected, the trouble of consecutive shot is avoided and production of rainbow noise due to overwrite at consecutive shot is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a helical scan type magnetic recording/reproducing device, and in particular relates to a transition in which recording is temporarily interrupted and then restarted on the same magnetic tape. .

(Prior art) Helical scan type magnetic recording/reproducing device (hereinafter referred to as VT)
One way to use R is as a tsunagi-dori. When the scene being recorded ends, it enters a pause state, and when a new scene begins, it releases the pause and records this scene.On the magnetic tape, the scene recorded before the pause (hereinafter referred to as Following the video signal of the new scene (hereinafter referred to as "new scene"), the video signal of the new scene (hereinafter referred to as "new scene") is recorded.

In such continuous shooting, for example, "home VTR"
"Introduction" October 1980, published by Corona Publishing, pp. 192
-194, when the pause state is set, the magnetic tape is rewound by a length corresponding to 0.3 to 1 second and then stopped, and when the pause state is released, the magnetic tape is 0.
．． It runs in playback mode for 25 to 0.3 seconds, and then recording begins. While this playback mode is set,
Control is performed so that the video head tracks the video signal recording track of the opening scene of the rewound part,
The track in which the video signal of the new bath surface is recorded is formed consecutively to the track in which the video signal of the open scene is recorded.

This prevents the video head from tracking misaligned at the joint between the old and new recording areas during playback.
On the playback screen, the display will smoothly transition from the open scene to the new bath surface without any disturbance in the playback image.

[Problem to be solved by the invention]

However, in a VTR, a full-width erase head is used during recording, and as the magnetic tape is being erased, recording is performed by the video head on the erased portion.

However, in the above-mentioned continuous shooting, since the full-width erasing head is provided at a certain distance from the video head, erasing is not performed on the portion of the magnetic tape that is rewound along with the paused state. For this reason, in the rewound part after the pause state is released and the playback mode for tracking control is performed for 0.25 to 0.3 seconds, the video signal of the opening scene is recorded on the track. So-called overwriting is performed to form one rack of video signals of the fresh water surface.

On the other hand, when recording a video signal, the video a signal is divided into a brightness signal and a chroma signal, the brightness signal is FM modulated to become a high frequency FM brightness signal, and the chroma signal is frequency converted to a low frequency signal. It becomes a low frequency converted chroma signal, and these FM
The wide signal, color signal conversion, and chroma signal are mixed and recorded on the magnetic tape.

Therefore, in the above-mentioned overwriting, since the high-frequency FM luminance signal has a short recording wavelength and the low-frequency low-frequency conversion chroma signal has a long recording wavelength on the magnetic tape, the overwriting of the video signal of the new hot water surface causes , the FMgMg signal in the video signal of the open scene recorded on the rack is erased, but the low-frequency converted chroma signal is not erased sufficiently. For this purpose, when you play the spliced magnetic tape, you can see the record of the old and new hot water surfaces 1! From the overwritten part of the Sakaki grain of the area,
The low frequency converted chroma signal of the video signal of the open scene will be mixed into the reproduced video signal of the new bath surface.

When performing continuous shooting by recording pauses and releasing pauses as described above, the overwriting period is sufficiently short, so this is not as much of a problem. When performing a continuous process of recording a new hot water surface following a new hot water surface, the following problem occurs due to overwriting.

That is, in a VTR, when the recording mode is changed to the stop mode, the magnetic tape stops as it is, and the above-mentioned rewinding is not performed.

Therefore, in order to record the video signal of the new hot water surface without any unrecorded area following the recording area of the open scene, the magnetic tape is rewound from the end of the recording area U of the open scene, and then the new hot water surface is recorded. However, since this rewinding is done by the user, rewinding can be quite costly, and when transitioning from stop mode to recording mode, recording is changed along with the recording mode setting. It will be started. For this reason, the overwritten area becomes long.

Then, if the low-frequency converted chroma signal of the opening scene is mixed in the video signal of the new bath surface that is reproduced from this overwritten part,
Due to the influence of this mixed low-frequency conversion Kuro No. 743, a rainbow-like color change (hereinafter referred to as rainbow noise) occurs in the reproduced image, but if the overwritten area is long as described above, this rainbow noise becomes noticeable. will be displayed.

As a method for suppressing such rainbow noise, which is also described in the above-mentioned known document, a rotating erase head (flying erase head) is provided in advance of the video head, and the flying erase head is installed at the same time as the recording mode is set. There is a method of erasing track by track, which can eliminate overwritten parts, but installing a flying erase head is very expensive and is not desirable for home VTRs. .

In addition, with conventional VTRs, in order to find the end of the recording area of a scene, it is determined by replaying it and looking at breaks in the playback screen, but finding this end is extremely time-consuming. It is something. For this reason, when the stop mode is entered at the end of the old scene, and the new hot water surface is subsequently recorded, the end of the old scene will be roughly set, and the necessary images at the end of the old scene will be removed. There was also the problem of putting it away.

It is an object of the present invention to provide a magnetic recording and reproducing apparatus that solves these problems, prevents the occurrence of rainbow noise due to overwriting during transition, and makes it possible to easily find the end of the recording area of the old scene. Our goal is to provide the following.

[Means to solve the problem]

In order to achieve the above object, the present invention cuts off the chroma signal for a certain period of time after a recording stop command, so that only the luminance signal is recorded.

Further, in the present invention, recording is continued for a certain period of time after a recording stop command is issued, and the chroma signal is gradually attenuated to zero within this certain period of time.

Furthermore, the present invention allows recording to continue for a certain period of time after a recording stop command is issued, gradually attenuates the chroma signal to zero within this certain period of time, and at the same time allows the chroma signal to be reduced to zero. Gradually increase the amplitude of the signal.

[For production]

From the end of the recording area of the scene, a recording area is provided in which only the brightness signal or the chroma signal gradually attenuates and only the rx flaw signal appears. For this reason, when this scene is played back, as soon as the playback ends, ■ the raw screen becomes a black and white screen or the color gradually disappears and becomes both black and white, and the scene is recorded! The end of the area becomes clear.

In addition, in the above area where only the luminance signal is recorded or the area where the chroma signal is sufficiently attenuated, the luminance signal is
Since it is recorded with M modulation, even if the video signal of the new hot water surface is overwritten, the already recorded flaw signal will be sufficiently erased, and when the overwritten portion is played back, the chroma signal will not be played back or the chroma signal will not be played back. Even if it is, the amplitude is sufficiently small that rainbow noise will not occur.

〔Example〕 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic recording and reproducing apparatus according to the present invention, in which l is an input terminal for a video signal, 2 is an input terminal for a control signal, and 3 is a 03D (ON 5CREE) input terminal.
N DISPLAY), 4 is a Y/C separator, 5 is a recording luminance signal processing circuit, 6 is a recording chroma signal processing circuit, 7
8 is a switch, 8 is a Y/C mixer, and 9 is an output terminal.

In the figure, the video signal input from input terminal l is
08D3 to the Y/C separator 4, and the brightness is 48
Separated into No. Y and Chroma (No. i C).

The separated luminance rx and signal Y are subjected to processing such as FM modulation in the recording luminance signal processing circuit 5 to become a high-frequency FM luminance signal. The chroma signal C is subjected to processing such as frequency conversion in the recording chroma signal processing circuit 6 and becomes a low-frequency transition chroma signal.
Y/C mixer 8 via switch 7 which is normally on
is supplied to The Y/C mixer 8 mixes the FM luminance signal and the low frequency converted chroma signal, and this mixed signal is supplied to the video head from the output terminal 9 via a recording amplifier (not shown) and recorded on the magnetic tape.

03D3 is for outputting a video signal for displaying characters on both sides and a video signal for turning the screen blue (hereinafter referred to as a blue video signal), and a control signal is input from input terminal 2. Then, 03D3 outputs a blue video signal. Further, this control No. 48 turns off the switch 7. This control signal is input from the input terminal 2 for a certain period of time together with the setting of the stop mode, and after this time has elapsed, the VT
R is set to stop mode.

Therefore, when the stop mode is set at the end of the old scene, a control signal is input from input terminal 2 for a certain period of time, and 03D3 outputs a blue video signal instead of the video signal from input terminal 1, and at the same time Switch 7 is turned off.

As a result, the luminance signal Y of the blue video signal is separated by the Y/C divider 4 and processed by the recording Hirohiro signal processor 1 circuit 5, and only the obtained FM luminance signal is sent to the Y/C mixer 8. The video signal is supplied to the video head via the video head and recorded on the magnetic tape.

After the predetermined period of time has elapsed, the magnetic tape stops and enters the standstill mode, the OSD3 stops outputting the blue video signal, and the switch 7 returns to the on state.

In this way, an area where only the FM luminance signal is not recorded is provided on the magnetic tape following the end of the recording area of the old scene.

By the way, if you play back the area where only this FM brightness signal is recorded, both sides will be uniformly blue.Since this is the FM modulated blue signal brightness signal, both sides of the playback will have a uniform 911 degree angle. The screen becomes a white screen. For this reason, when the old scene is replayed and the reproduced screen becomes a white screen, it can be easily determined that this is the end of the recording area of this old scene.

Furthermore, if the video signal of the new hot water surface is overwritten in the recording area of only this FM luminance signal, the FMIi degree signal is sufficiently erased by the video signal of the new hot water surface because the recording wavelength is short.
Further, since no undesired low-frequency signals are mixed into the video No. 43 of the new hot water surface that is reproduced in the overwritten portion, rainbow noise will not occur.

Therefore, the end of the recording area of the old scene can be determined by the display of the white screen, and a transition can be made to make the signal recording area of this white screen the overwriting area of the new hot water surface. The cylindrical part detects the end of the recording area of the old scene at the time of transition, so it is possible to perform the transition without damaging the old scene image, and also prevents rainbow noise when playing back the overwritten part. can.

Also, it is not necessary to start recording the new hot water surface exactly from the end of the recording area of the old scene, even if there is a gap between the end of the recording area of the old scene and the start of the recording area of the new hot water surface. Since the FM brightness signal is recorded, there will be no unrecorded areas, and by setting this interval sufficiently small, the white screen when moving from the old scene to the new hot water surface on the playback screen will not be noticeable. It can be done.

FIG. 2 is a block diagram showing another embodiment of the magnetic recording/reproducing apparatus according to the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals.

This embodiment is the same as the embodiment shown in FIG. 1 except that 03D3 is removed.

In the figure, a video signal of an old scene is input from input terminal 1, and this video signal is recorded in the same manner as in the embodiment shown in FIG. When the stop mode operation is performed at the end of this old scene, a control signal is input from input terminal 2 for a certain period of time, switch 7 is turned off, and the low frequency conversion chroma signal is cut off.

For this reason, only the FM modulated luminance signal of the old scene is recorded during the period of this control signal, after which the stop mode is entered.

In the embodiment shown in FIG. 1, the playback screen becomes uniformly white as soon as the playback of the video signal of the old scene ends, but in the embodiment shown in FIG. 2, as soon as the playback of the video signal of the old scene ends, , a black and white image is displayed on the playback screen, and this also makes it possible to detect the end of the recording area of the old scene, providing the same effect as the embodiment shown in FIG.

FIG. 3 is a block diagram showing still another embodiment of the magnetic recording and reproducing apparatus according to the present invention, in which 10 is a brightness amplitude variable circuit, 11 is a chroma amplitude variable circuit, and the parts corresponding to FIG. The same reference numerals are used to omit duplicate explanations.

In the figure, when recording a scene, the luminance signal Y separated by the Y/C separator 4 passes through the luminance amplitude variable circuit 10 as it is, is supplied to the recording luminance signal processing circuit 5, and is sent from the recording chroma signal processing circuit 6. Output low frequency converted chroma signal C
' passes through the chroma amplitude variable circuit 11 and is connected to the Y/C mixer 8.
is supplied to

When the stop mode is operated at the end of this scene, a control signal is input from the input terminal 2 for a certain period of time, and this causes the brightness amplitude variable circuit 10 to gradually increase the level of the brightness signal to uniformly reach the white level. and chroma amplitude variable circuit 1
1, the level of the low-frequency converted chroma signal C' is gradually lowered to uniformly become zero. When the input of the control signal is completed, the stop mode is set.

Therefore, when the playback of the recording area of this scene is finished, the brightness will gradually increase and the color will disappear on the playback screen.
Eventually, a uniform white screen will appear. Therefore, the end of the recording area of the scene can be easily determined, and the same effect as the previous embodiment can be obtained.

A fade-out effect can be created at the seam of the new hot water surface.

FIG. 4 is a block diagram showing still another embodiment of the magnetic recording/reproducing apparatus according to the present invention, and parts corresponding to those in FIG. 3 are given the same reference numerals.

In this embodiment, the brightness amplitude variable circuit 10 in FIG. 3 is removed. Therefore, as is clear from the explanation of FIG. 3, the chroma amplitude variable circuit 11 is controlled by the control signal from the input terminal 2. The level of the low-frequency converted chroma signal only gradually decreases to zero. For this reason, when the reproduction of the recorded area of the scene is finished, the color gradually disappears on the reproduction screen until it becomes a black and white image. This also allows the end of the recording area of the scene to be easily determined, and the same effect as in the previous embodiment can be obtained. In this embodiment, a color fade-out effect can be obtained at the joint between the old and new hot water surfaces.

In the embodiments shown in FIGS. 3 and 4, rainbow noise can be prevented by overwriting the video signal of the new hot water surface at a portion where the level of the low-frequency conversion chroma signal has sufficiently attenuated.

Further, in the embodiment shown in FIG. 3, the brightness amplitude variable circuit 10 uniformly maintains the white level of the brightness signal Y during the period of the control signal, and instead of the chroma amplitude variable circuit 11, the brightness amplitude variable circuit 10 controls the brightness signal Y during the period of the control signal. A switch to turn it off may be provided.

Furthermore, in FIGS. 1 and 2, the switch 7 may be provided immediately before the recording chroma signal processing circuit 6, or similarly,
In FIGS. 3 and 4, the variable chroma amplitude circuit 11 may be provided immediately before the recording chroma signal processing circuit 6.

〔Effect of the invention〕

As explained above, according to the present invention, the old scene record! j
! The area can be easily detected, and the recording start position of the new hot water surface can be easily set without requiring precision. Excellent effects can be obtained, such as preventing the generation of noise and also making it possible to perform splicing without damaging the recording area of the old scene.

[Brief explanation of the drawing]

Figure 1. FIGS. 2, 3, and 4 are block diagrams showing embodiments of the magnetic recording/reproducing apparatus according to the present invention. 1... Video signal input terminal, 2... Control signal input terminal, 3... O8D, 4... Y/C separator, 5...
- Recording luminance signal processing circuit, 6... Recording chroma signal processing circuit, 7... Switch, 8... Y/C mixer, 10
... Luminance amplitude variable circuit, 11... Chroma amplitude variable circuit. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a magnetic recording and reproducing device that performs FM modulation on the luminance signal of an input video signal and converts the chroma signal into a low frequency range for recording and reproduction, the luminance is FM modulated for a certain period of time along with a recording stop command. A magnetic recording/reproducing device characterized in that it is provided with means for converting only a signal into a recording signal. 2. In claim 1, the recording signal by the means is an FM
A magnetic recording/reproducing device characterized by a modulated luminance signal of constant amplitude. 3. A magnetic recording and reproducing apparatus according to claim 1, wherein the recording signal by said means is an FM-modulated luminance signal of said input video signal. 4. In a magnetic recording/reproducing device that performs FM modulation on the luminance signal of an input video signal and low frequency converts the chroma signal for recording/reproduction, recording is continued for a certain period of time after a recording stop command, and the chroma signal is 1. A magnetic recording/reproducing device comprising means for gradually reducing the amplitude of the signal or the low frequency converted chroma signal to zero. 5. The magnetic recording and reproducing apparatus according to claim 4, further comprising means for gradually increasing the amplitude of the luminance signal of the input video signal within the certain period of time to uniformly maintain the white level.