JP2696951B2 - Recording device and playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for recording a digital image signal on a recording medium and a reproducing apparatus for reproducing the digital image signal from the recording medium.

[Conventional technology]

Digital signals can be completely reconstructed as long as the playback S / N level is above a certain value, so they are attracting attention for high-quality recording / playback. Digital video recording is performed in which a digital video signal obtained as a result is recorded on a magnetic tape, magnetic disk, or optical disk. In a digital VTR that digitally records a video signal on a magnetic tape, the digital video signal is recorded at a track pitch that provides a minimum allowable S / N.
The long-time recording mode realized by the current analog recording / reproducing VTR is addressed by reducing digital data (bandwidth compression).

Recent advances in digital / recording / reproduction and band compression technologies have been remarkable, and a sufficiently satisfactory reproduced image can be obtained even in the long-time mode, and the long-time mode has been frequently used from the viewpoint of effective use of the magnetic tape. Is coming.

[Problems to be solved by the invention]

In recent years, as non-interlaced monitor devices have become popular, so-called double scan cameras that generate twice as much information as conventional cameras have emerged. However, conventional VT
In R, the output signal could not be recorded.

Accordingly, it is an object of the present invention to provide a digital signal recording device and a reproducing device which can respond to a plurality of types of video signals.

[Means for solving the problem]

The recording device according to the present invention is a supply unit for selectively supplying one system of digital image signals having a predetermined information amount per screen and n systems of digital image signals each having the predetermined information amount per screen. And compressing the information amount of the one-system digital image signal supplied by the supply means to obtain a first digital image signal at a predetermined rate, and the n-system digital image signal supplied by the supply means Compression means for compressing the information amount of each of the above, and multiplexing the compressed digital image signals of n systems to obtain a second digital image signal of one system having a higher rate than the predetermined rate; Recording means for selectively recording the image signal and the second digital image signal on a recording medium.

According to the reproducing apparatus of the present invention, a first digital image signal having a predetermined rate is multiplexed with n-system digital image signals, and a second digital image signal having a higher rate than the first digital signal is obtained.
Reproducing means for selectively reproducing the digital image signal from the recording medium; and the first signal reproduced by the reproducing means.
The information amount of the digital image signal is expanded to obtain one system of digital image signals having a predetermined amount of information per screen, and the second digital image signal reproduced by the reproducing means is converted into n system digital image signals. Decompressing means for decompressing the information amount of each of the n types of digital image signals to obtain n types of digital image signals each having the predetermined amount of information per screen; Output means for selectively outputting one system of digital image signals and n systems of digital image signals is provided.

[Operation] By the above means, one system of digital image signals having a predetermined information amount per screen and n systems of digital image signals each having the predetermined information amount per screen can be recorded and reproduced by the same processing system. Become like

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a basic configuration of a recording / reproducing system which enables simultaneous recording and simultaneous reproduction of two systems of video signals, and FIG.
1 is a block diagram showing the configuration of an input circuit connected to the input side of FIG.
FIG. 1B is a block diagram showing the configuration of an output circuit connected to the output side of FIG.

First, the standard mode will be described. In this mode, switches 22 and 58 are connected to contact a and switches 104 and 110 are connected to contact b. The video signal input to the input terminal 100 is sampled and hold by sample-and-hold (S / H) circuit 106, 8f _sc by an A / D converter 108 (f _sc is the color of the NTSC system subcarrier frequency) are sampled at , 8-bit digital signals. The output of the A / D converter 108 is a latch circuit 112
, And becomes a 4f _sc / 8 bit digital signal.
It is applied to the input terminal 10A of FIG.

In FIG. 1, a sub-sampling circuit 14A has an input terminal 10A.
Is decimated by a field offset or a line offset, compressed to a signal having a sampling rate of 2 _fsc , and supplied to the a contact of the switch 22. The distribution circuit 24 distributes the signal from the switch 22 to two systems. The signals distributed to the two systems by the distribution circuit 24 are respectively supplied to the ECC encoding circuit 2
The signals are supplied to switches 30A and 30B via 6A and 26B and modulation circuits 28A and 28B. The ECC encoding circuits 26A and 26B perform processing such as addition of an error detection / correction code and interleaving.
A and 28B convert to a signal having a small DC component suitable for digital recording.

In the standard mode, the switches 30A and 30B alternately switch to the a contact and the b contact at a period of 1/120 second. Signal is recording amplifier 32
Amplified by ~ 35, and magnetic tape 40 by magnetic heads 36 ~ 39
Is magnetically recorded. The arrangement of the magnetic heads 36 to 39 is shown in FIG. In FIG. 2, reference numeral 72 denotes a rotating head drum. FIG. 2A is a plan view of the rotary drum 72 as viewed from above, and FIG. 2B is a layout view of the heads 36 to 39 as viewed from the side surface of the drum 72.
Head 36 and 37 constitute a pair head, and head 36 is +
Azimuth, head 37 is -azimuth, FIG. 2 (b)
As shown in the figure, the height is one track pitch (T _p )
Different by a minute. The heads 38 and 39 also have the same relationship as the heads 36 and 37, and these two pairs of heads face each other at an interval of 180 degrees. The rotating head drum 72 rotates at 3,600 rpm,
The magnetic tape 40 is wound around its outer periphery for about 180 °. Therefore, in the standard mode, as shown in FIG. 3A, one field of a video signal having a field frequency of 60 Hz is recorded on four tracks.

A case where the video signal recorded in the standard mode is reproduced will be described. Magnetic tape 40 by magnetic head 36-39
The signals reproduced from are supplied to the switches 48A and 48B via the reproduction amplifiers 44 to 47. The switches 48A and 48B are switched between the a-contact and the b-contact at a 1/120 second cycle, as in the case of recording. The detection circuits 50A and 50B are composed of a waveform equalizing unit, a clock reproducing unit, and a discriminating unit. The discriminating unit compares "0" and "1" with a bit time obtained from the clock reproducing unit. Determine. Demodulators 52A and 52B are detection circuits 5
The outputs of 0A and 50B are demodulated, and the ECC decoding circuits 54A and 54B perform error detection / correction and deinterleave processing. The synthesis circuit 56 is EC
The outputs of the C decoding circuits 54A and 54B are combined and output as one system signal. In the standard mode, the switch 58 is connected to the contact a, and the output of the synthesizing circuit 56 is output from the output terminal 70A after the interpolated sampling points are interpolated by the interpolation circuit 66A.

In the standard mode, the switches 202 and 204 shown in FIG. 1B are connected to the contact a, and the signal of the output terminal 70A is
Is output to

Next, the operation in the long time mode will be described. In this mode, the switches 22, 58, 104 are connected to contact b. The analog video signal at the input terminal 100 is sent to the S / H circuit 106, A / D converter 10
8 and the sub-sampling circuit 14A perform the same processing as in the standard mode, and the scale / index (S / I) encoding circuit 1
Applied to 6A. The S / I encoding circuit 16A is a circuit that performs scale / index encoding, and the MIN-MAX method is generally famous. In the MIN-MAX method, an image is divided into blocks, and the maximum value and the minimum value in the block are equally divided and quantized. The index of which quantization level belongs to each pixel is transmitted, and the maximum value
By sending the minimum value, it is possible to reproduce the quantized representative value on the receiving side.

For example, 16 (= 4 × 4) pixels are defined as one block, the maximum value / minimum value is each 8 bits as a scale component, and all 16 pixels are assigned a 3-bit index obtained by dividing the interval between the maximum value / minimum value into eight. As a result, the information amount of 128 bits / block when all 16 pixels are quantized by 8 bits,
Only 64 (= 2 × 8 + 16 × 3) bits / block is required.

The signal whose data amount has been halved by the S / I encoding circuit 16A is compressed on the time axis by the time axis conversion circuit 18, and
It is applied to the distribution circuit 24 via the contact. The distribution circuit 24 distributes the input signal to two signal processing systems. ECC encoding circuit 2
6A and 26B perform the above-described processing on the output of the distribution circuit 24 and output intermittently according to the recording rate. For example, head
Assuming that the rotation speed of the drum 72 is constant at 3,600 rpm, in the long time mode, recording is performed only with the paired heads including the heads 36 and 37. Modulation circuits 28A and 28B are ECC encoding circuits 26A and 26
Modulate the output of B in the same way as in standard mode, and switch 3
Apply to 0A and 30B.

The switches 30A and 30B repeat connection and disconnection at the 1/60 second cycle in accordance with the output timing of the ECC encoding circuits 26A and 26B. The signals at the contacts a of the switches 30A and 30B are applied to the magnetic heads 36 and 37 via the recording amplifiers 32 and 33, and are recorded on the magnetic tape 40.

In the long time mode, the capstan motor 42 rotates at half the speed in the standard mode according to an instruction from the system controller 44, and the recording format on the magnetic tape 40 is as shown in FIG. )become that way.

When reproducing the recording signal in such a long time mode, only the heads 36 and 37 are used, and the reproduced signal is applied to the a contacts of the switches 48A and 48B via the reproducing amplifiers 44 and 45, respectively. Detection circuits 50A, 50B, modulation circuits 52A, 52B and EC
The signal is supplied to the synthesizing circuit 56 via the C decoding circuits 54A and 54B. EC
The C decoding circuits 54A and 54B perform error detection / correction and deinterleave processing, and then convert the time axis. The signal made continuous by the synthesizing circuit 56 is applied to the time base extending circuit 62 via the contact b of the switch 58, where the time base is extended. The scale / index decoding circuit 64A decodes the output data of the time axis decompression circuit 62 into a representative value of 8 bits per sample, performs block raster conversion, and outputs the result. The interpolation circuit 66A interpolates the data decimated by the sub-sampling circuit 14A. Switches 202 and 20 even in long-time mode
Reference numeral 4 is connected to the contact a, and the output of the interpolation circuit 66A is supplied to the terminal 214 via the output terminal 70A and the switch 202.

Next, the recording mode of the double scan signal will be described. In this double scan recording mode, 525 scanning lines are used as a signal source.
The book uses a camera that scans 60 frames per second. The double scan signal is input from the input terminal 102. In this mode, the switches 104 and 110 are connected to the b contact, and the input signal is input to the A / D converter 108 via the S / H circuit 106 and is converted into an 8-bit digital signal. The digital signal quantized by 8f _sc / 8 bits is switched line by line by a switch 118, and is written into the two-line memories 114 and 116 at a frequency of 8f _sc . The signals from the memories 114 and 116 are read at a frequency of 4 _fsc , and two-channel non-interlaced signals having 525 horizontal scanning lines are formed and supplied to the inputs 10A and 10B in addition to the inputs shown in FIG.

In this double scan mode, switches 22 and 5 in FIG.
8 is connected to the c contact. The video signal input to the input terminal 10A is subjected to the same processing as in the long-time mode by the sub-sampling circuit 14A and the S / I encoding circuit 16A, and then supplied to the synthesizing circuit 20. The video signal input to the input terminal 10B undergoes the same processing as the video signal at the input terminal 10A by the sub-sampling circuit 14B and the S / I encoding circuit 16B, and is then supplied to the synthesizing circuit 20. The synthesizing circuit 20 includes a time axis conversion circuit and a switching circuit, and synthesizes both inputs. The synthesized signal has the same data rate as in the standard mode, and the same processing as in the standard mode is performed after the distribution circuit 24.

The synthesizing circuit 20 controls the input terminal 10A so that the pair heads 36 and 37 are supplied with the video signal of the input terminal 10A, and the pair heads 37 and 38 are supplied with the video signal of the input terminal 10B.
The signal at the input terminal 10B is time-axis-compressed during the period when the signal is not supplied, and the signal at the input terminal 10A and the signal at the input terminal 10B are switched to a signal at the standard mode data rate.
The recording format of the magnetic tape is as shown in FIG.
Same as standard mode.

Reproduction will be described. The same processing as in the standard mode is performed from the heads 36 to 39 to the combining circuit 56. The output of the synthesizing circuit 56 is supplied to the distribution circuit 60 via the c contact of the switch 58. The distribution circuit 60 is composed of a switching circuit and a time axis conversion circuit.The reproduction signals from the heads 36 and 37 are output to the time axis conversion circuit 62, and the reproduction signals from the heads 38 and 39 are subjected to time axis expansion and S / I conversion. Output to the decoding circuit 64B. The same processing as in the long time mode is performed in the S / I decoding circuit 64B and the interpolation circuit 64B,
Output to the output terminal 70B. The signal expanded by the time axis conversion circuit 62 is subjected to the same processing as in the long time mode by the S / I decoding circuit 64A and the interpolation circuit 66A, and is output to the output terminal 70A.

When playing back a recorded signal in double scan mode,
Switches 202 and 204 (FIG. 1B) are connected to contact b,
Terminal 70A, 2-channel signals from 70B are written at a frequency 4f _sc in 2 line memory 206, 208. Memory 206,2
08 signals are read out at a frequency 8f _sc is a multiple of the speed of writing. The switch 210 is switched at the horizontal scanning frequency at the time of double scanning, so that the signal at the terminal 212 is a double scanning signal similar to that at the time of recording.

FIGS. 4, 5, and 6 show connection examples of a digital VTR 80 according to an embodiment of the present invention, a tuner, a camera, and a monitor device. When the ordinary interlace camera 81 is used as an input device, the VTR 80 can be operated in the standard mode and the long-time mode, and can be output to the ordinary interlace scanning monitor device 84. When the tuner 82 is used as an input device, normal interlaced scanning is used.
The data can be recorded / reproduced on / from the VTR 80 and output to the monitor device 84 for normal interlaced scanning. When using a double scan camera 83 that can output 60 frames per second with 525 scanning lines as an input device, the signal from the camera 83 is divided into two channels.
The data is recorded on the VTR 80, and the reproduced signal can be displayed on the double scan monitor 85.

〔The invention's effect〕

As can be seen from the above description, according to the present invention, it is possible to record and reproduce a signal having a picture quality equivalent to the long-time mode and having an information amount of n times the normal amount.

[Brief description of the drawings]

1 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 1A is a block diagram showing a configuration of an input circuit shown in FIG. 1, FIG. 1B is a block diagram showing a configuration of an output circuit shown in FIG. 1, and FIG. / Recording head layout diagram, FIG. 3 is a diagram showing a recording track pattern of a magnetic tape, and FIGS. 4, 5, and 6 are diagrams showing connection between an embodiment of the present invention and an input device and an output device. It is an example. 10A, 10B ... input terminal, 16A, 16B ... scale / index coding circuit, 18, 62 ... time axis conversion circuit, 26A, 26B ...
... Error detection / correction circuit, 36 ... Head A +, 37 ... Head A-, 38 ... Head B +, 39 ... Head B-, 44 ...
System controller, 64A, 64B …… Scale / index decoding circuit

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soichi Kashida 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Inside the Tamagawa Works of Canon Inc. (56) References JP-A-63-135077 (JP, A)

Claims (2)

(57) [Claims] A supply means for selectively supplying one system of digital image signals having a predetermined amount of information per screen and n systems of digital image signals each having the predetermined information amount per screen; The information amount of the one-system digital image signal supplied by the supply unit is compressed to obtain a first digital image signal of a predetermined rate, and the information amount of the n-system digital image signal supplied by the supply unit Compression means for compressing each of the compressed digital image signals and multiplexing the compressed n digital image signals to obtain a first digital image signal having a higher rate than the predetermined rate; Recording means for selectively recording the second digital image signal on a recording medium. 2. A first digital image signal having a predetermined rate and n-system digital image signals are multiplexed, and a second digital image signal having a higher rate than the first digital signal is selectively output from a recording medium. A reproducing means for reproducing, and an information amount of the first digital image signal reproduced by the reproducing means is extended to obtain a digital image signal of one system having a predetermined information amount per screen, and The second digital image signal to be reproduced is separated into n types of digital image signals, and the information amount of the n types of digital image signals is decompressed, respectively, and the n types of n types of image signals each having the predetermined information amount per screen are obtained. Decompression means for obtaining a digital image signal; one digital image signal and n digital image signals decompressed by the decompression means Reproducing apparatus characterized by comprising an output means for outputting selectively the.