JPS60191594A - Special reproducing circuit of video disc player - Google Patents

Abstract

PURPOSE:To attain special reproduction without reproducing an unpleasant still picture at a joint of a pattern by inhibiting track jump for still picture reproduction at four-field after the joint. CONSTITUTION:An extraction pulse generating circuit 27 inputs a jump inhibition signal D to an extraction pulse inhibition signal detection circuit 28 in synchronizing the inserted position of the signal D so as to detect the signal D. A detected output of the circuit 28 is utilized as a control signal of a pulse gate circuit 29 and the passing of the timing pulse is detected by detecting the signal D. The track jump output is inputted to a tracking mirror drive coil and the track jump for two-track's share is attained in the returning direction at still reproduction. Thus, in scanning a discontinuous pattern, since the track jump is inhibited, the normal reproduction is conducted for four fields from the start of the discontinuous pattern and then the slow motion reproduction is attained again.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a special playback circuit for a video disc player that plays back high-quality video signals.

(b) Prior Art A video disc player that optically plays back a video disc record in which one frame of an NTSC color video signal is recorded at a constant angular velocity over one recording track, repeats a track jump to an adjacent trunk once per frame. Still image playback continues by scanning the track.

(Refer to equity 54-15485) However, the video signal band is 20MHz audio signal audio sound 7
In the case of a high-quality video signal of MHz, it is not possible to record one frame of the video signal in one revolution. Therefore, in Japanese Patent Application No. 513-185608, the applicant previously recorded one field of a high-definition video signal on one round of a recording track, and when playing still images, a track jump of two tracks was made once every two fields. We proposed a method for repeatedly playing still images.

However, in the above proposal, since the disk record is rotated at high speed in a field period, the recordable time is shortened.

Therefore, if a wideband video signal is converted using the Zabusample TCI transmission method, which is a transmission method for high-quality video signals, the frequency band will be 8 MHz, so recording and playback can be performed at the same rotation speed as before. becomes. This sub-sample TCI transmission method was published in October 1982.
As stated in the ``Television Society Technical Report'' published on August 20, the recolor signal is compressed and multiplexed in the time axis during the horizontal blanking period using the straight TCI method, and each field is While changing the sampling point of
This is a new transmission method that thins out data to 4 times and transmits it.

According to this method, one screen is formed by four fields, and it is possible to reproduce a still image by continuously reproducing the four fields. Therefore, in order to play still images from a video disk record that rotates at a frame period of 4.
All you have to do is make a two-track jump in the field.

However, when performing special playback such as slow motion while sequentially changing the still playback position, or when playing still images across the screen seam where the recorded content changes, there is a risk that the screen may become distorted. .

(c) Purpose of the Invention Therefore, the present invention proposes a new and effective special reproduction circuit that performs special reproduction without reproducing unsightly still images at the joints of screens.

(d) Structure of the Invention The present invention is characterized in that track jumps for still image reproduction are prohibited in four fields after the seam.

(e) Examples The present invention will be described below with reference to illustrative embodiments.

In the first embodiment, as shown in FIG. 2, when creating a video disc record, a high-quality video signal is output to a TCI encoder (1>), a color signal is converted into a line-sequential signal, and a luminance signal is converted. 4H (H is the horizontal synchronization period) in advance, line-sequential color signals are compressed on the time axis and multiplexed during the horizontal blanking period.

The encoded output is input to a sub-sample filter 2), which switches the phase by π/2 for each field.
The encoded output is sampled with a 2MH2 sampling pulse, and the encoded frequency band of approximately 20 MHz is converted to approximately 8 MHz to realize multiplexed subsamples.

A part of the encoded output output is sent to the motion vector detection circuit (
3) is also input, and a motion correction signal is derived by detecting the movement (panning or telt) of the entire screen and vector-coding the direction. .

A part of the multiplexed sub-sampled output is input to the motion block detection circuit (4), and the screen is divided into 6 horizontal blocks and 32 vertical blocks, and the presence or absence of motion is detected for each block. A control signal is derived.

On the other hand, the audio signal is input to the audio encoding circuit 5), where it is compressed on the time axis to less than the vertical blanking period, and then encoded into three values to be derived as a PCM audio signal.

Furthermore, in this embodiment, the switching output of a switcher that switches and derives the output of the high-quality camera is input to the screen switching detection circuit (5) to generate a jump prohibition signal (D).

In this embodiment, the jump prohibition signal (D) indicates the start of a discontinuous screen (start of a new field) in synchronization with an empty line in the vertical jump period preceding the video signal of each field. The signal is emitted continuously for 4 fields.

Figure 4 shows the discontinuous points in the video disc record (DR) (7) recording track and the jump inhibit signal (DI
>(D2)(, p*)(DI) is schematically illustrated.

However, the jump prohibition signal (D) only needs to function as an identification signal during a track jump, and in the second embodiment, a jump signal (J') that specifies jump control for each field is constantly multiplexed. Then, from the start of the discontinuous screen, the jump signal (J
) may be prohibited.

FIG. 5 shows discontinuous points in the recording track of a video disc record (DR) and jump signals <Jl) to (J
s) schematically illustrates the positional relationship of FIG.

Furthermore, it is preferable to superimpose the jump signal (J) in the second embodiment or the jump prohibition signal (D) in the first embodiment for each field, but the multiplexed signal ensures that an empty line is provided in each field. If this is not possible, the jump signal (J) or jump prohibition signal (D
) may be multiplexed.

The multiplexed sub-sampled signal, motion compensation signal, block control signal, PCM audio signal, and jump inhibition signal (D) derived in this way are input to the multiplexing circuit (7), and a series of wideband video signals ( Band 8MH2).

This wideband video signal has a frequency shift range of 14 to 16 MHz.
It can be input to the FM modulation circuit (8) designated as z. This FM modulated wave can be recorded on a video disc as an information signal, but the frequency range of 4 to 16 MHz, which includes the frequency shift range and the first lower sideband (6 to 14 MHz), is necessary for recording and reproducing without SN deterioration.
is extracted through the first bandpass filter.

The allowable residual jitter of a high-quality video signal is limited to 2n5ec or less compared to a normal color video signal.

Therefore, horizontal synchronization period 1/33.75X 10° (=1
#+) Even if the jitter is corrected by sec, the residual jitter is 2n.
It cannot be limited to less than sec. Therefore, it becomes necessary to detect jitter at a period longer than the horizontal synchronization period.

Therefore, it becomes necessary to superimpose a pilot signal with a period longer than the horizontal synchronization period on the information signal. However, if the pilot signal is a multiplied output of the horizontal synchronization period or a frequency close to it, striped beat noise becomes noticeable. Therefore, in this embodiment, the pyro/torrent borrowed frequency 5, horizontal synchronization frequency 5□, and 5
r = (n + 1/2) SH, 5, and an interleave relationship is selected.

This 172 interleave frequency is equal to 112 horizontal scan lines.
If one frame is composed of five trees and one frame is recorded in one round of the illuminance recording track, as long as the track jumps two trees at a time, the pilot signal will drop out during the jump period but its phase will continue.

Therefore, in this embodiment, the fixed oscillator of the high-quality video camera has a frequency of 48 MHz, which is twice the color subcarrier frequency of 24.3 MHz.
．． Considering that 6MHz is selected, the fixed oscillation output is input to the 1764 frequency divider circuit (10), and its fundamental wave component of 759.395KHz (45㎠/2) is extracted through the low-pass filter (11〉). There is.

The information signal and the pilot signal are input to an adder circuit (12), and are added while limiting the pilot signal level to -35 db relative to the information signal level.

The addition output is input to the limiter (13) and is divided into low and high levels.
converted into a value signal.

This limit output is input to the optical modulation means (14) arranged in the optical system of the video disc recorder, and a recording track consisting of pits is formed on the video disc record rotating at a frame period (1/30 second). Ru.

Note that the signal recording system is the same as that of the well-known optical video disc recorder, so a detailed explanation will be omitted.

Next, the circuit operation of the video f-isk player, which is the gist of this embodiment, will be explained.

The preamplifier (15) that inputs the pickup output inputs the amplified output to the bypass filter (16χ) and the second handpass filter (17).

The bypass output separates the information signal including the first lower sideband and the frequency shift range, is input to the FM demodulation circuit (17) and returned to the wideband video signal, and then sent to the RF conversion circuit (not shown). The signal is then input to a band compression decoder exemplified in a high-definition television receiver.

This band compression decoder converts the RF conversion signal back into the original wide-band video signal, and by making full use of memory, synthesizes 4 consecutive fields of wide-band video (1 field of high-quality video signals from No. 8, It is supplied to high-definition television receivers.

That is, in order to synthesize a high-quality video signal, four fields must be continuously reproduced.

On the other hand, the hand bus output separates the reproduced pilot signal and is passed through a 90° phase shift circuit (18) to be used as a comparison input of an 11th phase comparison circuit (19).

This first phase comparator circuit (19) includes a multiplier circuit and a low-cross filter, and uses the output of a fixed reference oscillation circuit (20) as a reference input.

The first phase comparison output is supplied to a sick correction mirror or a variable delay circuit as a jitter correction output via a first phase compensation circuit (21).

Further, the reproduced pilot signal is converted into a continuous signal without dropouts caused by track jumps or the like via the AFC circuit 22), and is then input to the second phase comparator circuit (23) together with the reference signal.

This second phase comparison circuit (23) compares the phases by dividing both inputs by 1745, and the comparison period is set to 5H/2, which sufficiently tolerates rotational fluctuations.

The second phase comparison output is supplied to the disc motor as a disc motor control output via the second phase compensation circuit 24), and the video disc record is stably rotated at a frame period.

Therefore, the first phase comparator circuit closely removes the shifter and the second
The phase comparator circuit roughly removes the shifter and reproduces an information signal with almost no shifter.

- The circuit configuration described above operates during normal playback, and the following circuit operates for special playback.

First, the wideband video signal is input to a synchronization separation circuit (25), where it is separated into a horizontal synchronization signal and a frame synchronization signal.

The surface synchronization signal is input to a timing pulse generation circuit (26) and a sampling pulse generation circuit (27).

The timing pulse generation circuit (26) derives a timing pulse specifying the jump timing in field synchronization.

The sampling pulse generation circuit 27> inputs a sampling pulse synchronized with the insertion position of the jump prohibition signal (D) to the prohibition male detection circuit (28>), and generates a transfer prohibition signal CD.
This makes it possible to detect

The detection output of the prohibition signal detection circuit (28) is overlapped with the control 11 of the pulse gate circuit (29) to detect the jump prohibition signal <D) and prohibit the passage of the timing pulse.

The pulse gate output is input to a variable frequency divider circuit (30). This variable frequency divider circuit <30) is used for still playback.
The frequency is divided by 74, and when moving to the next field, the frequency is divided by 175.

Therefore, when playing 175 slot motion, the frequency division value should be set to 11.
5 → 115 → 115..., and when playing 1/7 slot motion, 115 → 1/4 → 1/4 → 115 → 1/
4 → 1/4 → 115-... Good <, 1/4 and 1
It is good to freely set the slow ratio among the 15 combinations.

If this output is input to the jump pulse generation circuit (31), a jump output to the truck is derived. Note that this track jump output is input to the tracking mirror drive coil, and enables a track jump of two tracks in the return direction during still playback. However, during other special playbacks, the number of tracks to jump to is 2m (m
is an integer), and the direction is not necessarily the return direction.

Therefore, when scanning a discontinuous screen, track jumping is prohibited, so normal playback is performed for four fields from the start of both discontinuous screens, and after that, slow motion playback becomes possible again.

In the first embodiment described above, a track jump is inhibited by reproducing a track jump prohibition signal, but a jump signal is inserted at field intervals except for four fields from the start of a discontinuous screen. When reproducing the video disc record of the second embodiment, as partially shown in FIG. is input to the jump signal detection circuit (28'), and the detection output is input directly to the variable frequency dividing circuit (30), which simplifies the circuit configuration compared to the first embodiment.

(f) Effects of the Invention According to the present invention, since still images are not reproduced in discontinuous portions of the screen, the unsightly appearance of the reproduced screen is eliminated, and the effect is excellent.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of a main part of a video disc player according to a first embodiment of the present invention, FIG. 2 is a block diagram of a main part of a video disc player of the same embodiment, and FIG. FIG. 4 is a partial circuit block diagram of the video disc player of the example, FIG. 4 is a schematic diagram of the video disc record of the first embodiment, and FIG. 5 is a schematic diagram of the video disc record of the second embodiment. . Explanation of main figure numbers, (DR)...Video disc record, (J)...
・Jump signal, (D)・Medium jump prohibition signal,
<31>...Jump pulse generation circuit. Applicant Japan Broadcasting Corporation Applicant Sanyo Electric Co., Ltd. Agent Patent Attorney Shizuo Sano Continuation of page 1 ■ Inventor Hideki Kokubu @ Inventor Yasuhiro Ishii @ Inventor Takeo Toyama [phase] Inventor Mori 1) Yoshihiko

Claims (2)

[Claims] (1) A video disc record in which a color signal of a high-quality video signal is multiplexed during a horizontal blanking period and one frame of a wideband video signal compressed using the multiplexing method is recorded for one revolution of the recording trunk. A video characterized in that it rotates at a frame period and skips two recording tracks at a rate of once per two rotations of the video disc L code, thereby continuously reproducing a wideband video signal of four consecutive fields. Special playback circuit for disc players. (2) The color signal of the high-quality video signal is multiplexed during the horizontal blanking period, and the wideband video signal is compressed using the multiplex subsampling method, and the discontinuous screen is switched to 1 to 4 fields. In a video disc player that plays back a video disc record which is made by recording an identification signal for identifying a prohibited area on a video disc record that rotates at a frame period, the track jump stopping area is determined based on the playback identification signal. A video disc player characterized in that it does not continuously reproduce four consecutive fields by identifying recording tracks other than the above and skipping two recording tracks in the return direction once every 12 revolutions of the disc. special regeneration circuit.