JPH0614727B2 - Magnetic recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording device such as a video tape recorder (VTR), and more particularly to a magnetic recording device having a high-quality still image recording function with a simple structure. Regarding the device.

(Prior Art) Recently, a camera and V such as 8 mm video and VHS-C are used.
The so-called camera-integrated VTR that integrates the TR is gaining popularity.

Such a VTR with a built-in camera is characterized by its small size and light weight, and it is suitable for taking videos while traveling or at sports events, but it is also sufficient for general use in terms of image quality. Various improvements have been made.

For example, in the case of an image pickup tube or image pickup element, which is also called the heart of a video camera, high sensitivity and high resolution have been achieved, and especially CCD
In this case, the number of pixels is increased to about 250,000, the resolution is improved by about 30%, and the smear phenomenon and the moire phenomenon are reduced.

As for the circuit, the S / N ratio is improved by improving the emphasis circuit and the comb filter.
Further, since the camera and the VTR are directly connected, the circuit for mixing the luminance signal and the color signal, the circuit for separating the two signals, and the like are omitted, so that the bands of the luminance signal and the color signal are not compressed and the resolution is reduced. There is also a merit unique to integration that improves color reproducibility.

By the way, in video shooting, it is common to take moving pictures of moving people, winds, etc. I often see still images.

In the VTR still image reproduction, blurring and noise often occur in the image, which is a phenomenon of a tracking error that occurs when the head does not accurately trace the video track on which the image to be reproduced is recorded. However, recently, a reproduction head dedicated to still images is mounted to reduce blurring and noise.

Note that in recent years, since a video printer for converting a video image into a hard copy has been developed, it is considered that it becomes popular to easily print and enjoy a still image of a video.

(Problems to be solved by the invention) However, still images are required to have a considerably high image quality, unlike moving images, because the information that does not change with time contained in one image is viewed as visual information. It Therefore, if the reproduced video signal contains jitter, dropout, or the like, an image deterioration phenomenon such as shake, distortion, color unevenness, or noise may appear in the image, and the still image may not be sufficiently watched. Further, when such a still image is hard-copied, the low image quality becomes even more noticeable.

So, video, especially VT with integrated camera as described above
Although the spread of R is remarkable, it is still far from silver salt photography in terms of image quality, and users use a camera-integrated VTR or a portable separation type camera for shooting movies, and a silver salt still camera for shooting still images. It is used properly,
Sometimes I am forced to carry both a video camera and a still camera.

Therefore, when considering the video system by dividing it into an imaging system, a recording system, and a hard copy system, a CCD with 400,000 pixels is being developed in the imaging system, and the appearance of the CCD will be near, and in the hard copy system. Recently, the image quality has improved considerably, and it is only a matter of time before it reaches a practically satisfactory level. Therefore, although the remaining recording system is the key, although various signal processing circuits have been developed or improved in order to improve the image quality, a still image with a high image quality that is sufficiently endurable for viewing has not been obtained.

In view of such problems, it is an object of the present invention to provide a magnetic recording device that not only records moving images but also records high-quality still images that can withstand viewing when necessary.
That is, if the magnetic recording device of the present invention is applied to, for example, a camera-integrated VTR, not only moving images can be shot with one video, but also high-quality still images can be shot at any time.

By the way, if you just add a still image recording function,
A variety of still image recording devices are provided, and it is easy to incorporate them into a video, and indeed some such attempts have been made so far. However, all of them are products that are unbalanced due to significant increase in weight and price. That is, in order for a video having a still image recording function to spread to general users, it is needless to say that it is possible to deal with higher image quality, but it is required that the weight increase is small, and for example, a device requiring a mechanism is required. It shouldn't be bad, and it shouldn't cost too much. However, a magnetic recording device satisfying such requirements has not yet been realized.

Therefore, another object of the present invention is to realize a magnetic recording apparatus capable of recording a high-quality still image with a small weight increase and at a low cost in order to provide a well-balanced popular type product. Especially.

Still another object of the present invention is to provide a magnetic recording device capable of selectively recording high-quality still images and high-quality audio.

DISCLOSURE OF THE INVENTION According to the present invention, a video track for recording a video signal for one unit image and a PCM track continuous on the extension of the video track are formed obliquely on a magnetic tape.
In a helical scanning type magnetic recording device in which an analog video signal of a moving image continuously given by one unit image in a unit image period is sequentially recorded on the video track, a still image recording switch for instructing still image recording, A first video signal suitable for video recording and a second video signal suitable for still image recording are created and output from an analog video signal of a video continuously provided for one unit image in one unit image period. Signal processing circuit, first recording means for modulating the first video signal output from the signal processing circuit and sequentially recording one unit image on one video track, still image recording from the still image recording switch Still image data generating means for taking in the second video signal for one unit image output from the signal processing circuit in response to the command and converting the second video signal into digital image data; and 1 unit image content of a still image for the digital image data generated by the still image data generating means, while dividing the required plurality partial image data, converts each partial image data to the PCM signal, P of the partial image data
A second recording means is provided for recording still image data for one unit image by sequentially recording the CM signal on each PCM track over the required plurality of PCM tracks.

In response to a still image recording command, a still image of one unit image (one frame or one field) is obtained from a video signal of a moving image obtained by shooting with an image pickup device or input from an external device through an input terminal. The video signal for recording is extracted and converted into digital image data for still images. The still image digital image data is divided into a plurality of partial image data, PCM-modulated, and then sequentially recorded on each PCM track. As a result, the video signal for recording a still image for one unit image is recorded over a plurality of required PCM tracks.

According to the present invention, while recording a video signal of a moving image on a magnetic tape, one frame of the moving image can be simultaneously recorded by a simple operation of operating a still image recording switch. When the present invention is applied to a camera-integrated VTR, not only moving images can be shot and recorded, but also still images (still photos) can be shot and recorded at any time.
By playing back still images that have been shot and recorded, they can be displayed on a television screen or printed. Furthermore, a still image can be repeatedly and automatically recorded at regular time intervals (for example, every 420 frames as shown in the embodiment described later).

In a preferred embodiment of the present invention, the magnetic recording apparatus further comprises means for converting a given analog audio signal into a digital audio signal and time-axis compression of the digital audio signal of one unit image period at a predetermined rate. A compression means and third recording means for converting the digital audio signal compressed by the compression means into a PCM signal and recording the PCM track when the PCM audio recording is selected are provided.

As a result, in addition to still image recording, it is possible to record audio signals that accompany moving image recording.

Preferably, the partial image data is selected when still image recording is selected, and the digital audio signal is selected when PCM audio recording is selected.
The PCM conversion circuit for converting into a signal is shared by the second recording means and the third recording means.

Since the PCM modulation circuit is used for both PCM still image recording and PCM audio recording, the structure is simplified, and it is possible to realize a lightweight and low-cost product.

(Embodiment) An embodiment in which the present invention is applied to an 8 mm video will be described below with reference to FIGS. 1 to 5.

8 mm Video Format First, the format of 8 mm video will be outlined with reference to FIGS. 4 and 5.

As you know, 8mm video is "8mm video conference"
However, the major differences from the conventional VHS system and β system are that the tape width is narrower, the audio signal recording system, the tracking system, and the like.

FIG. 4 shows the track arrangement on the magnetic tape in 8 mm video. The tape width is 8 mm and the material is coated or vapor-deposited metal tape. Each track is diagonally formed on the magnetic tape by the helical scan as in the conventional case, but the PCM track TR corresponding to the head scan 36 ° period is extended on the extension of the video track TR _V corresponding to the head scan 180 ° period. _P is provided. On each video track TR _V , a video signal (Video) is recorded by the low frequency conversion color difference signal recording method as in the conventional case, and F
The M audio signal (AFM) and the tracking pilot signal (TPS) are frequency-multiplexed and recorded. On the other hand, each P
The CM track TR _P is compressed audio signal over time is PCM recording a tracking pilot signal (TPS) is superimposed recorded. However, this PCM
Recording is optional, and post-recording is also possible.

As shown in FIG. 5, PCM tracks TR _P usually 18
Obtained by increasing the drum wrap angle which is 0 ° by 36 °. As can be seen from the head position in this figure, when one video head CH-1 finishes recording the video track TR _V , the other video head CH-
2 is adapted to perform the PCM recorded in the following PCM track TR _P.

Referring again to FIG. 4, a cue track TR _Q for recording a cue signal using fixed heads and an audio track TR _A for recording an after-recording audio signal are provided as options on the upper and lower sides of each scanning track TR.

The tracking pilot signal (TPS) is based on the automatic track finding (ATF) method, and four TPSs with different frequencies 1 to 4 selected within a band of about 100 kH to 160 kH are sequentially provided to each scanning track TR. Will be recorded. Then, during reproduction, tracking servo is applied so that accurate tracing is performed by detecting the head shift based on the frequency difference between the TPSs on both sides. Therefore, a fixed head type control track is not provided for 8 mm video.

Although outlined 8 mm video format, according to the present embodiment, as described later, a part of the video is recorded PCM still picture therein by utilizing the PCM track TR _P of 8 mm video, yet this PCM Still image recording is performed in the same PCM format as PCM audio recording. Thus, the PCM encoder has a PCM still image recording function and P
It is also used for the CM audio recording function.

Structure of Embodiment FIG. 1 shows the main structure of an 8 mm video according to this embodiment.

In this figure, light from a subject passes through the lens 10 and forms an image on the image pickup surface of the CCD 12. C
The CD 12 converts the image formed thereon into an electric signal, accumulates the electric signal, and drives the driving circuit 14 to perform horizontal / vertical scanning to output a video signal. This video signal is supplied to the camera process circuit 16, where it is subjected to signal processing such as noise reduction and gamma correction.

The luminance signal Y and the color signal C, into which the synchronization signal S is inserted, are supplied from the camera process circuit 16 to the modulation / recording circuit 18, where the luminance signal Y is FM-modulated and the color signal C is 3.
The frequency is converted from 58 MHz to about 743 kHz, and a phase conversion (PI) process is performed at that time. Then, the modulation / recording circuit 18 outputs a video signal Video which is a mixture of the FM luminance signal YFM and the low frequency conversion color signal C _0, and the video signal Video is output from the FM modulator 22 to the FM signal from the FM modulator 22 by the mixing circuit 24. Changeover switch 2 mixed with audio signal AFM
It is supplied to the magnetic heads 28 and 30 via 5 and 26 alternately at a field cycle. Incidentally, the microphone 20 outputs an audio signal _AU L of left and right channels, the AU _R, one channel is in the FM modulator 22, for example, a left channel audio signal AU _L is input.

The magnetic heads 28 and 30 are attached to the slit 32a at the substantially center of the cylinder 32, and are rotationally driven by the spindle motor 34 at the same number of revolutions as the frame frequency (30 revolutions per second). A magnetic tape 36 is obliquely wound around the cylinder 32 by 221 °, and is made to run at a constant speed by a tape running mechanism such as a capstan.
30 alternately scans the magnetic tape 36 obliquely, and an analog signal such as a video signal Video is recorded on the video track TR _V each time.

A magnet piece and a fixed head (not shown) are attached to the cylinder 32, and the magnetic heads 28, 30 are attached from the fixed head.
A pulse PG representing the rotation phase of the
G is given to the servo circuit 38. The servo circuit 38 is
The reference pulse P from the synchronization signal generation circuit 40 is used as the pulse PG.
The spindle motor 34 is controlled so that the rotation of the head is synchronized with the reference pulse PS by phase comparison with S, and
Servo is applied to the capstan motor 42 so as to keep the traveling speed of the magnetic tape 36 constant. Further, the servo circuit 38 gives switch switches SW1 and SW2 to the switches 25 and 26, respectively.

The components described so far are standard equipment for 8 mm video, and are almost common to the VHS system and β system.

Next, the PCM audio recording system equipped in this embodiment will be described. The two-channel audio signals AU _L and AU _R output from the microphone 20 are supplied to the switch 70.
To both input terminals 70a and 70b. The switch 70 has a switching signal S from the synchronization signal generating circuit 40.
Predetermined sampling frequency _H depending on M (31.5KH
z) Both input terminals 70a, with switching speed corresponding to
It is designed to switch to 70b alternately. The A / D converter 72 receives the clock signal C from the synchronization signal generation circuit 40.
M and receives analog audio signals AU _L and AU _R alternately to form a 10-bit digital audio signal AUD
Convert to _L , AUD _R.

These digital audio signals AUD _L , AUD _R
Is input to the compression circuit 74, where it is time-axis compressed to about 1/6 and subjected to 10-bit to 8-bit conversion processing. The time warp is used to record the PCM track TR _P of intermittent small section of the audio signal present sequentially in time, the digital audio signal AUD period corresponding to the head scanning interval 180 ° _L , AU
D _R is a digital audio signal of the period corresponding to the PCM track sections 36 ° audL, is converted into AUDR. In addition, 10-bit to 8-bit conversion is a small area PCM
By not be recorded only several 8-bit quantization bits to the track TR _P, it is for obtaining a 10-bit equivalent dynamic range in non-linear quantization of 10-8. Digital output from the compression circuit 74
The audio signals AUD _L and AUD _R are selected by a changeover switch 76.
Is input to the PCM encoder 68 via.

The PCM encoder 68 is commercially available for 8 mm video, in which error correction processing and modulation in the 8 mm video format are performed. That is, an 8-word 2-parity cross interleave code is used as an error correction code, and an address, a synchronization signal, parity, etc. are added to the data. A CRC code for error detection is also added. In addition to the video signal, the data includes I for index.
D words are also included. For the modulation, a kind of FM modulation called bi-phase modulation is used.
The later recording system can be used for both analog signals and PCM signals.

Then, the digital audio signals aud _L and aud _R input to the PCM encoder 68 are converted into PCM signals to which the error correction code is added, and the magnetic audio signals are outputted from the magnetic heads 28 and 30 via the changeover switches 25 and 26. It is adapted to be recorded in the PCM tracks TR _P of the tape 36.

Next, the PCM still image recording system of this embodiment will be described. From the camera process circuit 16, the luminance signal Y and the color difference signal RY,
BY is output and analog signals Y, RY, and
BY is a digital signal YD, (RY) D, (BY Y) converted to D. Therefore, in the case of component coding of 4: 1: 1, the change-over switch 40 changes over to the terminals 50a and 50b once during a period in which the luminance signal Y is sampled four times, and thereby, within that period. Color difference signals RY, BY
Are sampled once each. The changeover operation of the changeover switch 50 is performed in response to the changeover signal SQ from the synchronization signal generator 40.
Further, a clock signal CL for sampling and A / D conversion is given from the synchronization signal generator 40 to the A / D converters 52 and 54.

Here, the sampling frequency and the number of quantization bits in the A / D conversion have a great influence on the image quality, so they must be secured at a certain value or more, and they must be selected at least within the Nyquist band. The frequency should be 2MHz or higher, preferably 3MHz or higher,
The number of quantization bits must be 5 bits or more for the luminance signal Y + S, and 3 bits or more for the color difference signals RY and BY. However, as the number of bits increases, the processing circuit becomes complicated and the cost also rises, so that point must be taken into consideration. In the case of this embodiment, since the digital data of the 8 mm video format is 8 bits, the quantization bit is selected to be 8 bits accordingly. As for the sampling frequency, for example, the frequency characteristic of the luminance signal Y is 4.2 according to the image quality specification of a still image.
The frequency characteristics of the color difference signals RY and BY are determined to be substantially flat up to 1.0 MHz, and the END of
When a filter having a PASSBAND / START of STOPBAND ratio of 1: 1.3 is used, 4.2 × 1.3 × 2 = 10.92 MHz (1) or more is selected. Meanwhile, data bits per one field at 8 mm video, or data bit amount to be written to the PCM track TR _P 1050 words (1 word is 8 bits) are decided. Therefore, in the PCM still image recording of this embodiment, each PCM track T
Assuming that 1H of the video signal is PCM recorded in R _P , the sampling frequency _S for the luminance signal Y is 8 ( _3/2 × _S / _H ) = 8 in the case of component coding of 4: 1: 1. From × 1050 (2), 700 _H (≈11.01 MHz) was selected, which satisfies the above condition (1). In this case, the color difference signal R-
The sampling frequency _S / 4 for Y and BY is 17
It becomes 5 _H (≈2.75 MHz). In addition, the cylinder 32
Since 2H of the video signal is recorded by PCM for each rotation of, the number of effective scanning lines in one frame is 420.
An image of one frame (one frame) is recorded as a PCM still image per second.

The digital video signals YD, (RY) D, and (BY) D output from the A / D converters 52 and 54 are stored in the frame memory for one frame at a writing speed synchronized with the sampling frequency _S. 56 is input. When the magnetic head 28 or 30 scans a PCM track TR _P, so that there 1H of the video signal is PCM recorded, 1H component of the digital video signal YD, (R-Y) D ,
(BY) D is output from the frame memory 56 at a predetermined reading speed and supplied to the PCM encoder 68 via the changeover switch 76. In this way, the frame memory 56
Then, the digital video signals YD, (RY) D, (B-
Y) The 1H portion of D is read during the head scanning period of 36 °, and the whole frame is read, for example, in 7 seconds, so that the time axis expansion of the digital video signal is performed. Note that such a frame memory 56
The writing / reading operation of is controlled by the memory controller 58. A clock signal CK is supplied from the synchronizing signal generating circuit 40 and a control signal CT is supplied from the system controller 60 to the controller 58.

In the PCM encoder 68, the digital video signal YD,
For (RY) D and (RY) D, error correction processing and modulation similar to those for PCM audio recording are performed. Then, the digital video signal YD, (RY)
D and (BY) D are PCM encoders 68 for each 1H.
Is converted into a PCM signal to which an error correction code is added, and the magnetic head 28,
It is adapted to be recorded in the PCM tracks TR _P of the magnetic tape 36 than 30.

The changeover switches 25 and 26 are adapted to be alternately closed every head scanning period by the changeover signals SW1 and SW2 from the servo circuit 38. That is, the head 2
When 8 scans tape 36, switch 25 is closed and switch 26 is open. Then, the switch 25 first switches to the terminal 25A during the PCM recording period (PCM track scanning period) to switch to the PCM encoder 6
8 is sent to the head 28, and in the next moving image recording period (video track scanning period), it is switched to the terminal 25B and the analog video signals Video and F from the mixer 24 are fed.
The M audio signal AFM and the head 28 are input and sent. Similarly, during the period in which the head 30 scans the tape 36,
The switch 26 sequentially switches to terminals 26A and 26B,
On the other hand, the switch 25 is open.

The system controller 60 receives the system clock SC from the synchronization signal generation circuit 40 and also receives the servo circuit 3
The head phase pulse PG is received from 8 to control each part of the system. In particular, the system controller 60 includes a PCM still image recording button 6 attached to the outside of the camera housing.
In response to 2, the memory controller 58 is instructed to write and read the frame memory 56, and the switch 76 is switched to the terminal 76a. The PCM still image recording lamp 64 is provided in the viewfinder and
Lights up when a still image is being recorded to indicate that a still image is being recorded. Also, the system controller 60
Is a PCM audio recording button 63 on the outside of the camera housing.
In response to the change, switch 76 to terminal 76b
While in the M audio recording mode, the PCM audio recording lamp 65 in the finder is turned on. In this embodiment, the PCM still image recording button 62 and the PCM audio recording button 63 are configured such that when one button is pressed (ON), the other button returns (OFF).

In FIG. 1, the tracking pilot signal (T
The circuit for recording PS) is omitted.

Operation of Embodiment Next, the operation of the PCM still image recording according to this embodiment will be described with reference to FIG.

In FIG. 2 (A), the images taken by the CCD 12 are F1 and F.
It is shown that a moving image is formed by sequentially changing frame by frame, such as 2, F3 .... Each frame image Fi has the analog video signal Vide as described above.
In the form of o, it is recorded on two continuous video tracks TR _V , ia, TR _V , ib on the magnetic tape 36 shown in FIG. 2 (B).

First, at time to, PCM audio record button 6
3 is pressed, which selects the PCM audio recording mode. In this mode, the switch 76 is switched to the terminal 76b in FIG.
The encoder 68 receives the digital audio signals audL and audR from the compression circuit 74 in each PCM track T.
It is input within the scanning period of R _P. Then, in each of the PCM tracks TR _P , 1a, TR _P , 1b ..., the digital audio signals audL and audR are added to the PCM signal Pa.
Recorded in the form of ud. At this time, the PCM audio recording lamp 65 is lit.

Now, the PCM still image recording according to the present embodiment is performed in response to the operation of the PCM still image recording button 62. In FIG. 2, the PCM still image recording button 62 is pressed at time t1,
At this time, the moving image of the frame image F50 is being recorded. In response to the button operation, the system controller 60 switches the switch 76 to the terminal 76a at the recording start time t2 of the next frame image F51, and the memory controller 5
8 is instructed to write in the frame memory 56. In addition,
When the PCM still image recording button 62 is pressed, P
The CM audio recording button 63 returns. Then,
From time t2, the digital signals YD, (RY) D, and (BY) D representing the frame image F51 are transferred to the frame memory 5
Data is input to 6. At the same time, the system controller 60 turns on the PCM still image recording lamp 64,
The PCM audio recording lamp 65 is turned off.

Digital signals YD, (RY) D, and (B) representing the frame image F51 thus captured in the frame memory 56.
-Y) D is in the form of a PCM signal for each 1H after a predetermined time,
A plurality of consecutive PCM tracks TR _P , i to TR _P , j
Will be recorded over. In this embodiment, the number of effective scanning lines is 4
Since there are 20 tracks, 420 PCM track TRs
_{P, 81a~TR P,} PCM signal F51 · P of 1H minutes to 290b
1 to F51 and P420 are recorded, and the recording time is 7 seconds. The 30 PCM tracks TR _P , 51a to TR _P , 80b before the PCM tracks TR _P , 81a.
Although the still image data is not recorded (when 1 second has elapsed), the header HE, the control data CD, and the like are recorded.

In this way, when the PCM still image recording of the frame image F51 is completed, the next still image frame cycle Tc is entered, in which the frame image F291 is PCM still over the 420 continuous PCM tracks in the same manner as described above. The image is recorded.

As described above, in the present embodiment, when the PCM still image recording button 62 is pressed to enter the PCM still image recording mode, the recording of the moving image is performed without interruption according to the 8 mm format, and at the same time, the moving image in the moving image is recorded. 1 frame (1 frame image F
i) is selected at a constant cycle, and one frame is recorded as a PCM still image on a PCM track of 8 mm format.

Therefore, when the heads 28 and 30 or the reproducing head have uneven rotation, the tape 36 expands and contracts, and running unevenness occurs, the reproduced signal is accompanied by jitter, but the PCM signal reproduced from the PCM track is processed in the PCM reproducing process. Since the jitter is effectively removed by, the reproduced still image without shaking or distortion can be obtained. The reproduced still image is 1H read from each of the 420 PCM tracks.
It is formed by connecting the PCM signals for one minute and performing a PCM demodulation and D / A conversion to generate a standard analog video signal for one frame.

In addition, dropouts inevitably occur in VTRs due to scratches on the tape or head, dust adhesion, etc., but this is also restored brilliantly by the powerful error correction capability of PCM. For example, the redundancy due to error correction codes is 40%. With this setting, the effect of dropout is almost eliminated, and good reproduced still images can be obtained. In addition, various image quality deterioration phenomena due to analog recording are hardly found in the still image of PCM recording according to the present embodiment, and the storage stability of recording and the repeatability of reproduction are excellent.

As described above, according to the present embodiment, since one frame of a moving image is automatically recorded in a PCM signal at a constant cycle while the moving image is being captured, a frame (frame image) recorded later in the PCM still image is recorded. When PCM is played back on a TV screen or made into a hard copy, you can enjoy extremely high-quality still image playback that is comparable to, but not as good as, silver halide photography. Further, since PCM recording is performed on the same magnetic tape 36 by the same magnetic heads 28 and 30 for recording a moving image, no special mechanism is required and an increase in weight and shape is not caused. In addition, the PCM track of 8mm video is used, and there is almost the same P as PCM audio.
Since PCM still image recording is performed in the CM format,
Since the PCM encoder can be used for both the PCM still image recording function and the PCM audio recording function, there is a great cost advantage.

That is, the 8-mm video according to the present embodiment is a popular camera-integrated video that is lightweight, low-cost, and has the function of a high-quality still camera.

Modifications One embodiment has been described above, but the present invention is not limited to this, and various modifications and changes can be made within the scope of the technical idea thereof.

For example, the sampling frequency for PCM still image recording, the quantization characteristic, the recording time mode, etc. can be appropriately selected as necessary, and some examples are shown in FIG.

In FIG. 3, the A specifications are those selected in the above-described embodiment.

In the B specification, the H blank (horizontal blanking period) is not recorded. Since the image quality specification is high, the sampling frequency is increased accordingly, but the number of effective pixels (PIXEL) and the recording P
The number of CM tracks and the recording time are the same as those in the A specification.

The C specification is a line-sequential method in which the color difference signals RY and BY are alternately recorded every 1H, and is set to 1 under the condition that H blank is not recorded.
This is a method of PCM recording a 2H video signal on a PCM track. According to this specification, the number of recording PCM tracks and the recording time are each halved, but the image is slightly rough due to the low sampling frequency.

The D specification has the same conditions as the C specification, but the sampling frequency is made relatively large and the image quality is prioritized.
The number of M tracks and recording time have increased a little.

Although the four specifications have been exemplified above, of course, other specifications are possible. Further, in the above-described embodiment, the PC is used for each frame.
Although M still images were recorded, it is also possible to record them in field units.

Further, in the above-described embodiment, PCM still image recording and PCM
Only one of the audio recordings can be selected at a time, but both modes can be selected at the same time. In this case, the switch 70 does not alternately switch to both input terminals 70a and 70b, but rather to one input terminal, for example, 70a and the open position (terminals 70a and 70b).
In any switched alternately position without) and connected by an audio signal AU _L of the left channel is also sampling b, so as to be quantized, P is the switch 76
CM track TR _P both input terminals 76a during the scanning period of,
By alternately switching to 76b, the digital audio signal audL and the digital video signal YD, (R-
Y) D and (BY) D are alternately input to the PCM encoder 68 by 8 bits. That is, the digital video signals YD, (RY) D, and (BY) D are replaced with the digital audio signal audR of the right channel and the digital audio signal a of the left channel a.
To be PCM recorded in the PCM tracks TR _P with UDL. However, in this case, the time length of the still image frame cycle Tc is doubled, and the PCM audio becomes monaural.

Further, in the above-described embodiment, one frame of a moving image is automatically recorded in the PCM still image in a constant cycle in the PCM still image recording mode, but one frame of the moving image is recorded as a PCM still image at any time by button operation. It may be done.

The PCM still image recording according to the present invention can be performed in the after-recording format at a time different from the moving image recording, and in this case, a still image of a scene different from the moving image can be taken.

The present invention can also be applied to a so-called stationary 8 mm VTR, and can also record a television image as a PCM still image.

[Brief description of drawings]

FIG. 1 is a block diagram showing the main configuration of an 8 mm video to which an embodiment of the present invention is applied, and FIG. 2 is a diagram for explaining the operation of PCM still image recording according to the embodiment, and FIG. FIG. 4 is a diagram showing some specification examples of PCM still image recording of the present invention, FIG. 4 is a diagram showing track arrangement on a magnetic tape in the 8 mm video format, and FIG. 5 is an 8 mm video format. FIG. 6 is a diagram showing tape winding angles in FIG. 14 ... Camera process circuit, 25, 26 ... Changeover switch, 28, 30 ... Magnetic head, 32 ... Cylinder,
36 ... Magnetic tape, 40 ... Sync signal generating circuit, 50
...... Changeover switch, 52, 54 ...... A / D converter, 56
...... Frame memory, 58 …… Memory controller, 6
0 ... System controller, 62 ... Interrupt still image recording button, PCM audio recording button, 68 ... PCM
Encoder, 70 ... Changeover switch, 72 ... A / D converter, 74 ... Compression circuit, 76 ... Changeover switch.

Claims (4)

[Claims] 1. A video track for recording a video signal for one unit image and a PCM track continuous on the extension of the video track are formed obliquely on a magnetic tape.
In a helical scanning magnetic recording device in which analog video signals of a moving image continuously given for each unit image in a unit image period are sequentially recorded on the video track, a still image recording switch for instructing still image recording, A first video signal suitable for video recording and a second video signal suitable for still image recording are created and output from an analog video signal of a video continuously provided for one unit image in one unit image period. Signal processing circuit, a first recording means for modulating the first video signal output from the signal processing circuit and sequentially recording one unit image per video track, still image recording from the still image recording switch Still image data generating means for taking in the second video signal for one unit image output from the signal processing circuit in response to the command and converting it into digital image data, and While dividing the still image digital image data for one unit image generated by the still image data generation means into required plural partial image data, each partial image data is PCM.
Signal and convert the PCM signal of each partial image data to each PC
A magnetic recording apparatus comprising: second recording means for recording still image data for one unit image over the plurality of required PCM tracks by sequentially recording the data on M tracks. 2. A means for converting a given analog audio signal into a digital audio signal, a compression means for time-axis-compressing a digital audio signal of one unit image period at a predetermined ratio, and a PCM audio recording are selected. 3. The magnetic recording according to claim 1, further comprising: third recording means for converting the digital audio signal compressed by the compression means into a PCM signal and recording the PCM signal on the PCM track. apparatus. 3. The second recording means and the third recording means are shared, and partial image data is selected when still image recording is selected, and digital audio signal is selected when PCM audio recording is selected. The magnetic recording device according to claim 2, further comprising a PCM modulation circuit for converting into a PCM signal. 4. The PCM modulation circuit comprises a still image recording and a PC.
4. The magnetic recording apparatus according to claim 3, wherein when the M audio recording is selected, the partial image data and the digital audio signal are alternately converted into PCM signals by a predetermined amount.