JPH0810920B2 - Digital recording / playback device for television signals - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal digital recording / reproducing apparatus for recording / reproducing a digitized television signal.

2. Description of the Related Art As a conventional recording and reproducing apparatus for television signals, there is a 4: 2: 2 system digital VTR which is a standard for digital studio equipment. The 4: 2: 2 system records and reproduces signals obtained by sampling Y signals at 13.5 MHz × 8 bits and C _W and C _N signals at 6.75 MHz × 8 bits.

As a recording / playback device for a television signal that has been recorded for a long time, there is a device that performs band compression so as to reduce the data rate of the television signal, and the band compression method includes subsampling, DPCM, DCT, and vector. There are many methods that use methods such as quantization.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the digital recording / reproducing apparatus for a television signal as described above, two kinds of standard time recording and long time recording
There is a problem that one mode cannot be used for one mode.

In other words, for long-term recording, the conventional analog VTR (VHS
If only the tape feed speed is lowered (such as in the beta system or the like), the recording track width on the tape becomes narrower and the bit error rate of reproduction becomes worse due to interference such as crosstalk, so that good image quality cannot be obtained. There was a problem.

In view of the above point, the present invention ensures that the track width on the tape and the linear density in the track are exactly the same even when recording in both standard time recording mode and long time recording mode, and in the standard time mode. Provided is a digital recording / reproducing apparatus for a television signal, which can obtain a good image quality even if a recorded signal is reproduced in a long time mode or a signal recorded in a long time mode is reproduced in a standard time mode. It is a thing.

Means for Solving the Problems The present invention relates to a sub-sampling means for dividing an input television signal into n using a sub-sampling method, and m (1 ≦ 1) of television signals obtained from the sub-sampling means at the time of recording. (m ≦ n) Television signals having a phase of n are always rearranged so as to have a constant n phase periods, and at the time of reproduction, n or a predetermined number of phases of the television signals are arranged in the constant n phase periods. It is provided with a converting means for outputting a television signal and an interpolating and interpolating means for subjecting a television signal obtained from the converting means at the time of reproduction to a reproduced television signal by performing an interpolation process or an interpolation process. A television set in which the rotational speed of the rotary cylinder and the tape feed speed are multiplied by m / n in comparison with the case where m is equal to n according to the value of m. It is a digital recording / playback device for digital signals.

Action The present invention has the above-mentioned configuration, and m / m in the conversion means.
Even in a long-time recording mode such as recording a double compressed television signal, the rotation speed of the rotary cylinder and the tape feed speed are m / n times higher than in the standard time recording mode, and therefore recorded. In both modes, the signals have the same track width, track inclination angle, and the number of data in the tracks on the tape, and the conversion means output has a constant n phase period regardless of the value of m. The sampling phase arrangement is also the same. Therefore, not only the playback in both modes is possible by multiplying the rotation speed and tape running speed in the long-time playback mode by m / n in the standard time playback mode, but the recorded television signal is still image. If so, a high-definition television signal can be reproduced simply by interpolating the signals of the adjacent fields by the converting means and the interpolating / interpolating means. Moreover, since the tape pattern is the same, the signal recorded in the standard time recording mode can be recorded for a long time. A high-quality playback television that does not deteriorate bit errors due to narrow tracks and high cotton density even in slow playback that plays in playback mode and high-speed playback that plays back signals recorded in long-time recording mode in standard time playback mode The signal is obtained.

Embodiment FIG. 1 is a block diagram of a digital recording / reproducing apparatus for a television signal according to an embodiment of the present invention. FIG.
Is a recording time, and 1 is an input means for inputting a digitized television signal, and the input television signal is represented by g _(k) using a field number k (k is an integer). The sub-sampling means 2 obtains two signals g _{A (k)} and g _{B (k)} by dividing this g _(k) into two phases (phases of A and B) using a sub-sampling method. Transform means for arranging these g _{A (k)} and g _{B (k)} in phase order, 4
Is a rotary cylinder for recording the signal obtained from the converting means 3, and 5 is a tape to be recorded. At that time, the rotation speed of the rotating cylinder is v _s , and the tape feeding speed is v _t .
FIG. 1b shows a flow at the time of reproduction, in which a signal recorded from the tape 5'having a tape feeding speed v _t is transferred to a rotating cylinder _4'having a rotating speed V _s of g _{A (k)} , g _{B (k )} , The signals arranged in phase order are reproduced. The converting means 3 separately outputs g _{A (k)} and g _{B (k)} arranged in the order of phase, which is opposite to that at the time of recording. Interpolates g _{A (k)} and g _{B (k)} from the sub-sampling means 2 in the opposite manner, or when there is no phase in either one, interpolates and interpolates from other phase and the signals of the preceding and following fields. It is an interpolating / interpolating means for transmitting the result (g _(k)) to the output means 7 for reproduction.

First, the recording operation of the above embodiment will be described. FIG. 2 shows one sub-sampling method in the sub-sampling means 2 shown in FIG. 1. Two sub-samplings of the k-th field television signal g _(k) arranged in a grid pattern in the form of a quincunx are shown. The phase (g _{A (k)} is marked with a circle and g _{B (k)} is marked with a circle). Conversion circuit 3, divided g _{A (k),} g _{B (k)} of the first half of the feed period g _{A (k),} rearranges such that g _{B (k).} The rearranged signals are recorded on the tape 5 having the tape feeding speed v _t by the rotating cylinder 4 having the rotation speed v _s . At this time, if one field data is recorded on two tracks on the tape pattern, the tape pattern is as shown in FIG.

The above is the description of the operation of this embodiment in the standard time recording mode. Next, the operation in the long time recording mode will be described.

In the long-time recording mode, the conversion means 3 is set to g _{A (k)} and g _{B (k).}
Only the signal of one of the phases is output. However, the kth
If the phase of A, that is, g _{A (k)} is output in the field, the position of B, that is, g _{B (k + 1)} in the next k + 1th field, and the phase of A, that is, g _{A (k + 1) in the k +} 2th field. So the order of the phases is the same as in standard time recording. The signal output from the conversion means 3 thus configured is half the data of the input television signal g _{(k) in} terms of data rate. Next, in the rotating cylinder 4 and the tape 5,
In the long-time recording mode, the rotation speed is v _s / 2 and the tape feed speed is v _t / 2, which is half the standard time recording mode. By doing so, the recorded tape pattern becomes as shown in FIG. Comparing FIG. 4 with the tape pattern in the standard time recording mode of FIG. 3, all of the track width, the track inclination angle, the number of data in the track, and the phase arrangement in which the phases A and B are alternately arranged are shown. Are the same, and are different only in the time interval between the tracks, and the tape pattern in FIG. 4 is formed by recording twice as long as that in FIG.

 Next, the operation during reproduction will be described.

First, when the signal recorded in the standard time recording mode is reproduced in the standard time reproducing mode, the tape feeding speed of the tape 5'and the rotation speed of the rotary cylinder 4'are the same v _t and v _s as those at the time of recording. , To the conversion means 3 in the order of g _{A (k)} and g _{B (k)} during the k-th field. Therefore, the interpolating / interpolating means 6 interpolates signals having two phases A and B opposite to those of the sub-sampling means 2 at the time of recording, and the input television signal g _(k) at the time of recording is reproduced as it is. It becomes the signal g ' _(k) .

Next, when the signal recorded in the long-time recording mode is reproduced in the long-time reproduction mode, the tape feeding speed of the tape 5'and the rotation speed of the rotary cylinder 4'are the same as those at the time of recording.
v _t / 2, v _s / 2. At that time, only g _{A (k)} is sent to the conversion means 3 during the k-th field. Therefore, the interpolation / interpolation means outputs a signal obtained by interpolating g _{B (k)} of B phase from g _{A (k)} as a reproduction signal g ′ _(k) . However, if the recorded signal is a still image, the reproduced signal is interpolated with the data of the fields before and after the reproduced signal to form a reproduced signal with high resolution and high image quality. Therefore, the converting means 3 interpolates and interpolates the signal g _{A (k)} of the kth field and the signal g _{B (k-1) of the (k-1)} th field or the signal g _{B (k-1)} of the _(k + 1 ₎ th field. It is sent to the means 6 to perform the same interpolation processing as in the standard time reproduction mode. However, switching between the still image / moving image can be easily realized by recording the control signal together with the image signal.

Next, a case where the signal recorded in the standard time recording mode is reproduced in the long time reproduction mode will be described. in this case,
This is so-called slow reproduction, which is the same as the operation for a still image in the long-time recording mode recording and the long-time reproduction mode reproduction described above. That is, the tape feed speed is v _t / 2,
Since the rotation speed is v _s / 2 and 1/2 times those at the time of recording,
For example, only g _{A (k)} is sent to the conversion means 3 during one field period, but g _{A (k)} is sent to the conversion means 3 during the next field period.
_{Since B (k)} is sent, the conversion means 3 interpolates g _{A (k)} and g _{B (k)} over the two-field period and sends it to the interpolation means 6 to perform interpolation processing, thereby completing the complete image quality. It is possible to perform slow playback at 1/2 speed.

Finally, the case where the signal recorded in the long time recording mode is reproduced in the standard time reproduction mode will be described. In this case, so-called high-speed reproduction is performed. Since the tape feed speed is v _t and the rotation speed is v _s, which is twice as high as those at the time of recording, signals g _{A (k)} and g _{B (k + 1 )} over two fields, for example, during one field period. ₎ Is sent to the conversion means 3. At this time, if the recorded signal is a moving image, either g _{A (k)} or g _{B (k + 1)} is interpolated and sent to the interpolating means 6 for interpolation processing. However, if the recorded signal is a still image, both the signals g _{A (k)} and g _{B (k + 1)} are sent to the interpolation / interpolation means 6 to perform the interpolation processing. By doing the above, a reproduced image with high resolution and high image quality can be obtained even at high speed reproduction.

In addition, in the present embodiment, as shown in FIG. 2, a sub-sampling method of dividing into two in a quincunx shape is used.
A method such as a sub-sampling method in which a signal is divided by taking out every other line may be used as long as it can reproduce a screen of one field with data of one phase by interpolation processing as in the long-time recording mode. .

Further, in the present embodiment, as shown in FIG. 2, sub-sampling is used to divide into two, but sub-sampling method of dividing into n (n is a positive integer of 2 or more) such as 3 or 4 may be used. . At that time, a long-time recording mode that can record a television signal n times as long as the standard time recording mode is possible, and if the recording mode and the reproduction mode are switched, a shift from 1 / n times speed to n times speed is possible. It can be regenerated.

In addition, as shown in FIG. 3, the tape pattern in the standard time-change recording mode uses two 1-field television signals.
Although it is recorded in tracks, it may be recorded in one track, two tracks or more.
Further, the number of tracks may be other than the integer number such as 1.5 tracks.

Finally, in the present invention, the mode for recording all the data of the input television signal on the tape is the standard time recording mode, and the mode for recording only the data compressed by the sub-sampling is the long time recording mode. This is exactly the same according to the data rate recorded on the tape so that the recording mode is the standard image quality mode and the standard time recording mode is the high image quality mode.

As described above, according to the present invention, the tape pattern on the recorded tape, that is, the television signal is recorded in the standard time recording mode and in the long time recording mode in which band compression is performed by sub-sampling. Since the track width, track inclination angle, number of recorded data in the track, and subsampling phase arrangement are exactly the same, the signal recorded in either standard time or long time recording mode can be reproduced in either standard time or long time. Even if the image is reproduced in the mode, a reproduced image with good image quality can be obtained, and slow reproduction and high-speed reproduction can be easily performed by switching the recording and reproduction modes, which is a great practical effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a digital recording / reproducing apparatus for a television signal according to an embodiment of the present invention, and FIG. 2 is a pixel layout diagram showing a subsampling method of the embodiment. FIG. 3 is a tape pattern diagram in the case of recording in the standard time recording mode in the embodiment, and FIG. 4 is a tape pattern diagram in the case of recording in the long time recording mode in the embodiment. 2 ... subsampling means, 3 ... conversion means, 4,4 '
...... Rotary cylinder, 5,5 '…… Tape, 6 …… Interpolation, interpolation means.

Claims (1)

[Claims] 1. A sub-sampling means for dividing a digitized input television signal into n fields (n is a positive integer of 2 or more) of a 1-field television signal using a sub-sampling method, and the sub-sampling means at the time of recording. Only m (m is a positive integer satisfying 1 ≦ m ≦ n) television signals of phases are taken out from the n-divided television signals of n phases obtained by the above, but the output is irrespective of the value of m. Rearrange so that there are always constant n phase periods,
Conversion means for outputting n or a predetermined number of phases of the television signals arranged at a constant n phase period during reproduction, and n or a predetermined number obtained from the conversion means during reproduction. It is provided with an interpolating and interpolating means for performing a television signal of a number of phases by performing an interpolating process or an interpolating process to obtain a reproduced television signal. At the time of recording, m is changed to n according to the value of m in the converting means. In the case of equality, the digital signal of the television signal is characterized in that the rotational speed of the rotary cylinder for recording the television signal obtained by the converting means on the tape and the tape feed speed are respectively multiplied by m / n. Recording and playback device.