JPH0247981A - High definition television signal digital recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a picture natural visually by adopting a value of a still picture mode or a value of a moving picture mode in response to the speed of fast speed reproducion selectively and replacing the value into a control signal included in a reproducing signal and giving the resulting output. CONSTITUTION:A MUSE signal being the result of compressing a high definition TV signal is reproduced from a tape via a reproducing head 1. A control signal included in a reproducing signal is separated by a control signal separation circuit 7. Data of plural fields and plural sampling phases are mixed at the fast speed reproducing to form one field, then a switch 12 is turned to the down position to adopt a control signal set to a prescribed value. When the speed to the fast speed reproduction is a comparatively slow speed such as twice or four times, a switch 10 is turned to the down position to set the control signal to a value of the complete still picture mode. Moreover, when the speed of the fast reproduction is fast, the switch 10 is turned to the position of the UP side to set the control signal to a value in the moving picture mode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a digital re-recording and reproducing apparatus for MUSE signals, which records and reproduces high-definition television signals (MUSE signals) based on the MUSE system.

2. Description of the Related Art The MUSE method is a method for transmitting high-definition television signals using 1,000 channels of satellite broadcasting. In this method, a high-definition television signal with a band of 20 MHz is compressed to a baseband band of 8 MHz by multiple sub-Nyquist sampling, and then,
By frequency modulating, the transmission band is
This allows satellite broadcasting to be carried out on the same transmission channel as current broadcasting by keeping the channel width to 27MHz.

The sampling pattern according to the MUSE method is the same as shown in FIG. 2, and is compressed to one-fourth of the original band and transmitted.

- The force receiving side has a frame memory and reproduces the image using all the sampling points of the four fields that have been transmitted, but regarding the points that have not been transmitted as shown in Figure 2. Also, reproduction is performed by two-dimensional interpolation.

In this way, the original image can be completely reproduced for still images, but since the correlation between fields is low for video parts, if all four fields are used, the image will be blurred or the sampling pattern will be visible. occurs.

Therefore, to reproduce the moving image part, it is necessary to reproduce only from the currently sent sampling points for one field, without using the sampling points for four fields. For this reason, the transmission signal band of the video part is naturally narrow and the shift is noticeable, so as a countermeasure for this, when the entire screen moves in parallel such as panning, the motion vector is transmitted and interpolated between frames on the receiving side. Accurate interpolation is performed by correcting the position of the sampling point. With this method, in the case of parallel movement of the entire screen such as panning described above, it is possible to obtain a resolution comparable to that of a still image even though the image is moving.

As described above, this method is a band compression method for high-definition television signals that is suitable for both still images and moving images.
Various control signals such as correction position information of sampling points related to the video are superimposed and transmitted as digital information once per field within the vertical blanking period.
The position of the sampling point is corrected by controlling the read/write address of the frame memory in accordance with the control signal on the receiver side.

As explained above, the MUSE system is a signal format that can transmit high-definition television signals in a narrow band, so it can be used not only for television broadcasting by broadcasting satellites, but also for various recording and playback devices such as VTRs and video discs. Can be applied.

Here, a digital recording/reproducing device (hereinafter referred to as digital V
Let us consider the case where a MUSE signal is recorded and reproduced in a memory card (abbreviated as TR).

First, FIG. 3 shows a block diagram of a reproduction system of a generally known digital/L/VTR. The operation of the digital/L/VTR during reproduction will be explained using FIG.

The signal reproduced from the tape via the reproduction head 16 is
The signal is amplified by the reproduction amplifier 17 and written to the memory 19 via the reproduction processor 18. The memory 19 is a memory for restoring the signal randomized by interleaving during recording, and the original signal is restored by writing to the memory 19 according to the address information added during recording and sequentially reading it out. . The error correction decoder 20 corrects errors in the reproduced signal due to dropouts and detects errors based on the error correction code added during recording, and corrects errors that cannot be corrected by the error correction decoder 2o. In circuit 21, interpolation is performed with neighboring correlated samples based on the error flag so that error samples are visually less noticeable. The modified playback signal is
It is output from the output terminal 22.

When recording and reproducing the MUSE signal on the above-mentioned digital) VTR, in the case of normal playback, it is decoded by the receiver's decoder and becomes a high-quality television signal, no different from the signal received by satellite broadcasting. The signal is displayed on the screen, but the signal format changes when high-speed playback is performed.

The operation in high-speed playback will be explained below.

During high-speed reproduction, one field of a reproduction signal of a digital VTR is constructed using data of a plurality of different fields. For example, in the case of 4x speed, one field is constructed using data taken from four different fields. In addition, in order to use only the data from which the block atrea can be read in each field, if the number of error samples is large in one field during high-speed playback, corrections are made using interpolation and replacement. Configure. By the way, in the case of a MUSE signal, since the subsample phase differs for each field, one field during high-speed playback contains data of multiple different fields and data of four different subsample phases. It will be mixed. M
When input to the USE decoder, processing such as interpolation is performed based on control signals obtained from a plurality of different fields.

Problems to be Solved by the Invention However, the above-described high-definition television signal digital recording and reproducing apparatus has the following problems.

If the reproduced MUSE signal is determined to be a moving area by motion detection during high-speed playback, interpolation is performed using the sample data of the current one field, but the number of samples included in one field and the number of samples with the correct subsample phase are Since the number of samples is small and there are many samples that have been modified, it is not possible to obtain a sufficient image even if interpolation is performed. In addition, the digital/L/VTR has four feed memories corresponding to each subsample phase,
Another option would be to write the correct sub-sample data into the corresponding feed memory, hold the data for several fields until enough data has been written, and then send it to the decoder, but this would require four field memories. As the scale of the circuit increases, it is necessary to use data from fields in the past, which results in unnatural images in the case of moving images.

In view of this point, the present invention provides a method for achieving high-speed playback using a digital VTR that records and plays back MUSE signals, and that provides optimal image quality for high-speed playback images without adding a large-scale circuit. An object of the present invention is to provide a high-definition television signal digital recording and reproducing device.

Means for Solving the Problems The present invention is a digital recording and reproducing device that records and reproduces a MUSE signal obtained by band-compressing a high-definition television signal. This is a high-definition television signal digital recording and reproducing device characterized in that it selectively adopts a still image mode value or a moving image mode value, and outputs it in place of a control signal included in a reproduced signal.

Effect The present invention has the above-described configuration, and when recording and reproducing MUSE signals using a digital recording and reproducing device, when performing high-speed reproduction, the reproduction speed of high-speed reproduction is relatively slow, such as double or quadruple. In the case of speed, the control signal is forcibly set to full still image mode, the decoder side processes it as a still image, and if the playback speed of high-speed playback is high, the control signal is set to video mode. , and the decoder side processes it as a moving image, that is, reproduces one screen from only the sampling points of one field.

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

FIG. 1 is a diagram showing an embodiment of a MUSE signal digital recording/reproducing apparatus according to the present invention. In Figure 1,
1 is a playback head, 2 is a playback amplifier, 3 is a playback processor, 4 is a memory for restoring data randomized by interleaving to its original form, 5 is an error correction decoder that performs error correction and error detection of the playback signal, 6 is an error correction circuit that corrects error samples based on the error flag; 7 is a control signal separation circuit that separates the control signal from the playback signal; 8 is a video mode setting circuit that forces the control signal into video mode; 9 10 is a still image mode setting circuit that forces the control signal to set the still image mode; 10 is a switch that changes the setting of the control signal to video mode or still image mode; and 11 is a switch that sets subsample phase information. a sub-sample phase information setting circuit; 12 is a switch for selectively adopting either the value obtained from the playback head or the value set in the control signal setting circuits 8 and 9.11 as a control signal for the MUSE signal; 13 is a subsample phase information separation circuit that separates subsample phase information from the control signal selected by switch 12; 14 is a video signal based on a value obtained from the playback head or a control signal set to a predetermined value; A control signal insertion circuit 16 is an output terminal for a reproduction signal.

MUSE type digital VTR configured as above
The operation during high-speed playback will be explained below.

During high-speed reproduction, data of a plurality of different fields and a plurality of different sub-sample phases are mixed to form one field, so the value of the control signal read out in this case cannot be used.

Therefore, with the switch 12 in the lower position, a control signal set to a predetermined value is employed.

Here, when the high-speed playback speed is relatively slow, such as double or quadruple speed, the switch 10 is set to the lower side and the control signal is set to the value for the complete still image mode. In this case, the MUSE decoder that receives the reproduced MUSE signal from the digital/l/VTR performs interpolation using samples from four adjacent fields in order to treat all input data as a complete still image. For the samples used for interpolation, samples with the correct subsample phase,
Samples with different subsample phases and modified samples are mixed together, but for samples with different subsample phases, the phase deviation from the correct sample position is small, and many samples in the vicinity are By configuring the screen using the above-described method, acceptable image quality can be obtained as an image during high-speed playback.

Next, if the playback speed of high-speed playback is fast, switch 1o.
Set the control signal to the video mode value with the upper side. As mentioned above, when the control signal is set to complete still image mode and the MUSE decoder performs still image processing, the time difference between the sample points of the current field and the sample points of the past field becomes large. As the correlation disappears, image quality deterioration becomes more noticeable as the speed increases.

However, in video mode, one screen is played back from only the sample points of the current field, so the time difference between each sample point is small and the correlation is high, and although the resolution is slightly reduced, there is no significant deterioration in image quality. It is possible to prevent this. Note that in the case of the full-screen moving image mode, since the image is decoded using only the playback signal within one field, the motion vector is naturally not used.

In addition, during high-speed playback, by circulating the subsample phase information using the subsample phase information setter, the sample points of the four types of subsample phases are updated to new sample points in order, and the sample points of the specific subsample phase are It is possible to avoid the problem of sample points not being updated and past values remaining forever.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, in the case of high-speed reproduction, in MUSli: a digital recording and reproducing apparatus for recording and reproducing signals, a control signal is set to a predetermined value according to the speed of high-speed reproduction. As a result, there is no need to provide a special processing circuit on the MUSE decoder side, and the circuit added to the digital recording/playback device can be relatively small-scale, making it possible to obtain visually natural images with a simple configuration. The practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a high-definition television signal digital recording and reproducing apparatus according to an embodiment of the present invention, and FIG.
An explanatory diagram showing the sampling pattern of the USE signal,
FIG. 3 is a block diagram of a reproduction system of a digital VTR. 7... Control signal separation circuit, 14...
. . . Control signal insertion circuit, 8 . . . Video mode setting circuit, 9 . . . Still image mode setting circuit. -X-(1---X--0-Ichiko-4-X-()-X
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Claims (1)

[Claims] This is a digital recording and reproducing device that records and reproduces a MUSE signal obtained by band-compressing a high-definition television signal. A high-definition television signal digital recording and reproducing device characterized by selectively adopting a value and outputting the value in place of a control signal included in a reproduced signal.