JPH0294071A - Video signal recorder - Google Patents

Abstract

PURPOSE:To obtain a clear picture by dispersion-recording a part or all of static picture information extracted at the interval of the prescribed period from a video signal during the recording to a part or all of the sub-code area included in a prescribed plural tracks. CONSTITUTION:Sub-code areas 13-1, 13-2, 13-3 and 13-4 are provided between video and voice areas 12 corresponding to a tracing pattern 4 on respective video tracks. When the capacity of the sub-code area is 8,640 bits, 256 tracks are necessary in order to record the still picture full picture of one field. Therefore, the still picture full picture of one field is dispersion-recorded to areas 13-1, 13-2, 13-3, 13-4...13-2n (n=128) at the interval of 64 fields. An information reduction rate is made into 1/16 by a frame omission rate 1/64 and a necessary TG number (n=8) may be reduced. Further, n=8 is kept, the frame omission rate is raised to 1/16 and the density of the time direction may be raised. Thus, as the frame omission picture of the still picture, the picture, which has no noise bar and is natural and high in visibility, can be obtained.

Description

[Detailed description of the invention] Ru.

FIG. 2 is a diagram showing the structure of a video signal in an embodiment of the present invention. In this embodiment, 4-11 component encoding is performed, that is, the sampling frequency of the Y signal, ■ signal, and Q signal is 14 JMHz, 3.58 MIIz, and 3.5, respectively.
Consider the case of sampling at 8 MHz, quantizing at 8 bits, and recording. 21 indicates the number of effective pixels in one field of the Y signal, which is 768 pixels in the horizontal direction and 240 lines in the vertical direction. 22 indicates the number of effective pixels in one field of the I and Q signals, which are 192 pixels in the horizontal direction and 240 lines in the vertical direction, respectively.

The video signal bit rate in the above configuration is (768+
192 x 2) x 240 x 8 x 60
= 132 Mbps, and since it is difficult to record such a high bit rate signal directly with a small number of heads, the amount of information is compressed to 66 Mbps at the station using a band compression encoder (COD), which will be described later (Fig. 8, 88). do. 48 more
kllz, 16-bit 2-channel audio signal bit rate (48 x 16 x 2 = 1.54) Ab
ps) and the subcode area (Subcode
The data bit rate is 69.62 Mbps, which is the sum of the bit rate of 2.08 Mbps for Area).

In digital recording, parity is usually added to correct errors that occur during playback, a 5YNC signal is added as a timing reference during playback, and digital modulation (main data) is added to match the characteristics of the head medium. In the example, we assume 8-9 conversion), so the total bit rate increases, but
Normally, it is sufficient to see about 25%. Therefore, in this example, the total bit rate is 88 Mbps (redundancy 26.4%).
And so. Note that the configuration of 5YNCBLOC is the same as the conventional one (FIG. 9(C)).

FIG. 3 shows the head configuration and tape pattern in an embodiment of the present invention. He-nd 31-34 (he ten, heto, to)
is attached to a rotating drum (62φ) 35 so that two channels are opposite each other at 180° as shown in the figure, and the tape 36 is rotated at 3600 rpm in the scanning direction 37.
The tape 36 is scanned in the direction of
~44 are formed. In each track, 12 longitudinal areas are video and audio areas.
o Area), 13 is the subcode area.

Next, the basis for recording data at a total bit rate of 88 Mbps with the above configuration will be explained. The total number of data per field time is B (bits), the diameter of the drum is R (■), the shortest recording wavelength is λ (μm), the number of tracks required to record one field is N, and the channel frequency is If fch is fch (MHz), in this example of 180° winding, 3600 rpm, 2 channels simultaneous recording, R = 82 (mm), N = 4, λ = 0.53
μm, fch = 22MHz In other words, when a 62φ drum is rotated at 3BOOrpm, if all the data for one field is recorded on 4 tracks in one rotation with 2 channels simultaneous recording, the shortest recording wavelength is 0.53 μm and per channel. The frequency is 22 MIIz, which is a value that can be easily achieved at present.

In the above, the total number of bits in one track (after 8/!l conversion) is: Of this, the total number of valid bits before 8/9 conversion is 8/9 (
B/N) phantom 325 (bits) In addition, the number of effective bits in the subcode area above is increased to 8640 bits (108 (l)
Byta, 27% of all effective bits), 1 field still image (768 x 192 x 2) x 240
-276480 Bytes) in the subcode area requires 256 tracks (64 fields in time). Conversely, 1 in 64 fields
Still images for one field can be distributed and recorded in a subcode area of 256 tracks, and in this embodiment, the distribution is performed in accordance with a head tracing pattern corresponding to the magnification of high-speed search.

FIG. 4 is a schematic diagram showing the video track on the tape and the head tracing pattern during high-speed sana, and (a)
(b) shows four times speed, and (C) shows eight times speed (power of 2). In the figure, reference numeral 51 indicates a track group (hereinafter referred to as TG) consisting of two tracks formed simultaneously by two-channel heads;
The shaded area 52 is an area where a reproduced signal is obtained during each high-speed search, and reproduction is possible only at the same azimuth as during recording. Note that when the head end approaches the track boundary, the playback envelope decreases and errors increase; however, as mentioned above, the subcode area 13 is only 2.7% of the total track length, so the playback envelope does not decrease much. It's not easy.

As shown in FIG. 4, as the search magnification increases from standard playback, the playable area on each track rapidly decreases. FIG. 5 is a diagram illustrating a pixel pickup method for dispersively recording pixels of one original field in accordance with the above-mentioned tracing pattern, and FIG. 1 is a diagram showing a track pattern for an 8x search. FIG. 3 is a diagram showing the correspondence between the positions of subcode areas of each track and the pickup method of still image information. In addition, the figure shows the number of pixels in the horizontal direction
h, Y, 1. by simply changing the value of the number of pixels in the vertical direction nV.
Since it can be applied to any Q signal, the signals will not be distinguished in the following explanation. In Figure 1(a), 11 is TG
, N'o,, 12 is the video and audio area, 13-
113-2, 13-3, 13-4, . . . are subcode areas provided between the video and audio areas 13 corresponding to the tracing patterns 14 on each video track.

FIG. 1(b) shows the relationship between the frame drop rate of the frame drop still image recorded in the subcode area, the information reduction rate, and the required number of TGs.

As mentioned above, assuming that the capacity of each subcode area is 8640 bits, 256 tracks (+28 TG) are required to record a full still image of one field. Therefore, every 64 fields, one field of still image full screen (all pixels in Fig. 5) is added to the subcode area +3-1.13-2.
13-3. 13-4-, 13-2n (n = +28)
Distributed recording. Alternatively, the required number of TGs (n=8) may be reduced by setting the information reduction rate to 1716 at the same frame drop rate (1/64). In this case, pixels 61.65°62, . . . , [i8.69.70 . In this case, the picked pixels 61, 65, 82.・68.69-... and subcode area N.

You are free to respond accordingly.

Alternatively, the frame dropping rate may be increased to 1716 while n=8, thereby increasing the density in the time direction. In this case, the information reduction rate is 1
/64, in FIG. 5, pixel 6162,...
63.64. ... will be picked up. Other cases where n=1fi and 32.64 were also shown, but their explanation will be omitted.

FIG. 6 shows a method of displaying a still image recorded in the subcode area by the method described above on a monitor screen.

(a) is the display method when n-8, frame drop rate l/16, 61; 62.63.6 picked up during recording.
By displaying 4... with the same bits as the original still image, it becomes a 1/64 reduced image. Similarly, for (b), n=8 frame drop rate l/64 or n=32. Piece drop rate 1716
In the case of (C), n=16. This is a case where the frame drop rate is 1/16. Since (c) is a horizontally long display, interpolation may be performed in the vertical direction.

FIG. 8 is a block diagram of a recording/reproducing apparatus in an embodiment of the present invention. Note that the audio system is essentially irrelevant to the present invention and will therefore be omitted.

First, I will explain the recording process. Y converted to/D.

1. The input signals Y, I, and Q on the Q buses 81, 82, and 83 are field thinned out to the main RAIA 84 and subcode area 13 for recording continuous images in the video and audio areas 12, respectively. The data is supplied to a sub RAM 85 for recording still images.

M84 to main R has a first write address generator (WA
The Y, I, and Q signals are sequentially written by the first read address generator (RADRGEN) 86, and then the first read address generator (RADRGEN
I) 87, for example, a band compressor using block coding (COD188) generates a signal from -1-A1 to address for block extraction suitable for COD188, and generates Y+, q from RAIA84.
(G number (hereinafter referred to as image data 1-) is read out to the data bus (D version IIIsI) 119, and the amount of information is %ed by C0D88. The image data compressed by C0D88 is transferred to the data bus (DAT8B). IS2) Supplied to FCC Brosset!) (PROC) 91 at 90 Beniyu,
After parity for error correction is added, the signal is divided into two channels and converted into 8/9 by a modulator (MOD) 92 for each channel, and then sent to a synchronization signal addition circuit (SYN) 9.
A synchronizing signal is added at step 3, and the signal is recorded in the video and audio area 13 on the tape by a head (not shown).

Way n-8. If the frame drop rate is 1/16, sub RAM 85
2nd write address generator (DRGEN2 to W)
94, one field of image data is written into 16 fields, and then the second read address generator (RA
As shown in FIG. 5, the pixel 61 is
．． 62.63.64. ...(information reduction rate) 154) is read out and recorded in the subcode area 13 divided into areas on the same track via the data bus (DATA BUS2) 90 in the same process as the compressed image data. be done.

Next, the regeneration process will be described.

A synchronization signal detection circuit (SYN) 96 detects a synchronization signal for the video and audio area playback signals for each channel, and a demodulator (DEM) 97 performs 978 conversion, which is the reverse of that at the time of recording, and an FCC processor 91 performs error correction. ,
Only the image data is sent via the data bus 90 to the band compression decoder (
The data is decoded by DEC) 98, written to the main RAM 811 in band compression block units, read out at regular speed, and sent to Y, T, and Q buses 8182 and 83.

All reproduced signals from the subcode area are obtained in accordance with the tracing pattern, and the error is corrected in the same process as above, and the DRGE is sent to the third write address generator (W
N3) 100 sequentially sends subl(
A.M.85 is written to the third read address generator (
RADRGEN3)+01 displays Y, 1. in the display format shown in FIG. Read out to Q bus 81.82.83.

FIG. 7 shows another display example in which the display size is fixed. In this case, each time the information reduction rate in FIG. 1 is doubled, the horizontal or vertical resolution is doubled.

In the above example, the search magnification is 8 (@, n=B, 1
1 field 1 every 6 fields or 64 fields
All 8 bits of each pixel of a 1/64 or 1/16 still image of ~ were distributed and recorded in the subcode area of 16 TG (32 tracks), but the present invention is not limited to these numerical values, but Because human visual characteristics deteriorate,
It is not necessarily necessary to record 8 bits for all pixels, and the amount of information may be reduced by thinning out the pixels while keeping the upper 4 bits of all pixels or the resolution at 8 bits. For example, if the amount of information is determined by this method, other subcode information may be recorded in the subcode area of unnecessary tracks among the 256 tracks and used effectively, or the number of dropped frames may be reduced. i.e. % of 1 field every 8 fields
A still image with a reduced amount of information may be recorded. Koi-
By doing so, it is possible to improve the density in the time direction during the search.

As mentioned above, the subfield area is provided in the video track at a position corresponding to the head tracing pattern at a predetermined search speed in the longitudinal direction of the track, and one field is extracted from the original video signal every predetermined number of fields/frames. /By distributing and recording the still image information of a part or all of one frame in some or all of the subcode areas included in a plurality of predetermined video tracks, for example, noise bars can be recorded as frame-dropped images of still images during high-speed search. It is possible to obtain clear images that are natural and highly visible. Furthermore, by setting the search speed to a predetermined value, it has become possible to increase the resolution and time density as necessary. Further, since the subcode area records a frame-drop still image, it does not depend on the image data recorded in the video and audio areas (it may be f-range compressed).

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a natural, highly visible and clear image without noise bars as a drop-proof still image during a high-speed search, for example.

FIG. 9 is a diagram illustrating the structure of a recording signal, FIG. 10 is a diagram showing a trajectory of a conventional head, and FIG. 11 is a diagram illustrating pickup pixels during a conventional high-speed search.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the correspondence between the track pattern, the position of the subcode area on each track, and the pickup method of still image information, FIG. 2 is a diagram showing the structure of the video signal in the embodiment of the present invention, and FIG. is a diagram showing the head configuration and tape pattern in the same embodiment, FIG. 4 is a diagram showing a tracing pattern during search, FIG. 5 is an explanatory diagram of a pixel pickup method, and FIGS. 6 and 7 are search images. Figure 8 is a block diagram of the device of this embodiment, Figure 2 (b) 3 β Figure 3 (0> Figure (b) Figure 5 (0') (a) Cb) Figure 6 (C) Cb') (C) Figure A D Voo Figure 9 TR Figure 10 Figure 71

Claims (1)

[Claims] 1) A device that records video signals by sequentially forming a large number of parallel tracks using a rotating head, in which each track on a tape is run at a predetermined speed faster than the running speed during recording. A sub-code area is formed at a position corresponding to the pattern traced by the rotating head when the image is recorded, and part or all of the still image information extracted from the video signal being recorded at predetermined intervals is transferred to a sub-code area included in a predetermined plurality of tracks. A video signal recording device characterized in that recording is performed in a distributed manner over one or all subcode areas.