JPH03185683A - Video signal recorder - Google Patents

Abstract

PURPOSE:To reproduce a large number of video elements on a screen even at a different reproducing speed from a recording speed by changing over an arrangement of plural tracks to be recorded with prescribed video elements respectively to that of each screen and changing over a relationship of video elements in individual tracks corresponding to their positions on the screen to that in a unit of track. CONSTITUTION:A digital video signal is inputted to a system control circuit 12, where an increment of one frame is added to its internal data F for counting frame by frame. A number of tracks to be shifted is decided by an address control circuit 10 according to this data F, and an arrangement of the tracks is shifted by a frame memory 3. And, whenever a data for one track is derived from the memory 3, an increment of this is added by the system control circuit 10 to its internal data T, and an address control circuit 11 is operated in accordance with the data T, and then an arrangement of each track is rearranged. By this method, a recorded video signal is reproduced at any various reproducing speed in such a way that a large number of video elements on a screen are uniformly reproduced, and hence a good reproducing video can be obtained in a reproducing system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal recording device, and more particularly to a device that records video signals while forming a plurality of tracks on each side.

[Prior Art] Conventionally, in video signal recording and reproducing devices that digitally record video signals, recording errors and reproduction errors can be effectively corrected by performing digital recording with error correction and interleaving processing for error correction. This enabled the system to have good signal reproducibility.

That is, when forming an error correction code, pixels that cannot be corrected are distributed on the screen, and interleaving processing is performed to rearrange the data of each pixel so that there is no deterioration in image quality when errors are corrected. .

[Problems to be Solved by the Invention] However, conventional devices employ fixed rules for interleaving processing. For this reason, for example, in a digital VTR that performs special playback by transporting a magnetic tape at an integral multiple of the standard playback speed, a portion of the playback screen that is not played back may become unplayable for a long period of time. Furthermore, in a digital VTR, there is a high possibility that the tape will be damaged in the longitudinal direction of the tape, and even in this case, the same portion of the screen cannot be played back for a long time. Furthermore, in a device that performs multi-channel recording and playback, when one frame worth of image signals is recorded over multiple tracks, if one of the multiple heads becomes inoperable due to damage, etc., the on-screen All predetermined parts of the file cannot be played back.

6 and 7 are diagrams for explaining conventional problems, and FIG. 6 is a diagram showing the head configuration of a general digital VTR.
FIG. 7(A) is a diagram schematically showing the trace pattern on the tape by the head having the configuration shown in FIG. 6, and FIG. 7(B) is a diagram schematically showing the data to be reproduced in one screen's worth of data. It is.

As shown in FIG. 6, there are four rotating heads 22.2:
1. Wrap the magnetic tape 26 over an angular range of 180＠ or more around the rotating tram 20 that holds 24.
The rotating drum 20 is rotated at 200 r, pl. A pair of heads 22, 23 and 24 arranged in close proximity.
25 have different azimuth angles, and only tracks recorded with heads having the same azimuth angle can be reproduced.

FIG. 7(A) is a diagram showing the state of playback while transporting the tape 26 at twice the speed of recording. The numbers inside circles indicate the track numbers of each frame, and the shaded areas indicate each head. This shows the part that will be played. As shown in the figure, the reproduced signals are signals of the same portion of the track group of each frame. In the illustrated example, video signals for one frame are recorded on 12 tracks, but since the recording signals for each frame are arranged according to the same interleaving rule, only pixels at the same position on the screen are repeatedly displayed. It will be played.

FIG. 7(B) is a diagram showing the video signal for a frame in correspondence with 12 tracks. When the interleaving rule for each frame is the same as described above, the video signal for one frame is played back. includes only the pixels corresponding to the shaded areas twice. Therefore, the range of pixels that can be reproduced as a whole is narrow, and corrections such as interpolation cause pixels that cannot be reproduced in a wide range, making it impossible to obtain a good reproduced image.

Further, even if reproduction is continued in this state, only pixels occupying the same position on the screen will be repeatedly reproduced, and interpolation using correlation in the time axis direction cannot be performed.

Against this background, it is an object of the present invention to provide a video signal recording device that performs recording such that a large number of pixels on the screen can be reproduced even when the reproduction is performed at a speed different from that at the time of recording. With the goal.

[Means for Solving the Problem] According to the present invention, in an apparatus for recording a video signal while forming a plurality of tracks for each screen, a plurality of tracks each recording a predetermined pixel are provided. The track arrangement is changed for each screen, and the correspondence relationship between the pixels in each track and the position on the screen is changed for each track.

[Operation] With the configuration as described above, even if the same portion of the same track of each frame is repeatedly reproduced on the recording medium, a completely different portion will be reproduced on the reproduction screen. In other words, when recording with the same interleaving rule, this is equivalent to playing back a different part of a different track for each frame, so an extremely wide range of pixels on the screen can be played back, resulting in good playback. You can get the image.

[Example] Examples of the present invention will be described below.

FIGS. 1A and 1B are diagrams schematically showing recording patterns of video signals according to this embodiment. Figure 1 (A
) shows that the video signal for one frame is recorded on one track, and the number inside the circle in the figure is the track number of this frame. Also, the numbers in each track are horizontal scanning line numbers, and in this example, n per frame.
Assume that a video signal with p horizontal scanning lines is recorded.

Now, if the pixel data of each scanning line is arranged as shown in Fig. 1(A) for the first frame, the data of each scanning line is arranged as shown in Fig. 1(B) for the next frame. . That is, the scanning line data recorded on the third track in the first frame is recorded on the first track in the next frame. Similarly, the scanning line data recorded on the 4th to pth tracks in the first frame are recorded on the 2nd to (p-2)th tracks in the next frame.

In the 1st #th frame, 1.21! The data of the scanning line recorded on the i-th track will be (p-1) in the next frame.
, recorded on the first track.

That is, the recording tracks are shifted by two for each frame.

Further, as shown in the figure, the scanning lines recorded on each track are shifted by 9 scanning lines for each frame. That is, the data of the scanning line recorded on the first track in the first frame will be recorded on the (p-1)th track in the second frame, but the recording order is l in the first frame, (p+1), (p+2)...(np-p+1)
In the second frame, (IOp +1)
, (lip + 1) - (np - p+1), 1
．． The order is (p+1)...(8p+1)(9p+1). The same applies to other tracks.

Then, in the next (third) frame, the tracks to be recorded are similarly shifted by two, the scanning lines of each track are shifted by nine and recorded, and this is repeated thereafter. For the sequence, if p is a multiple of 2, it will be completed in (p/2) frames, and for the sequence of running lines of each track, if n is a multiple of 9, it will be completed in (n/9) frames.
) will be completed with a frame.

Next, the effects will be explained using FIGS. 2(A), (B) and FIGS. 3(A) to (E). Here, to simplify the explanation, it is assumed that the number p of tracks on which one frame worth of video signals is recorded is 12, the number of lines recorded per one track is 87, and the total number of lines of one frame is 1044. Figure 2 (A) is a diagram showing what happens when tapes recorded as in Figures 1 (A) and (B) are played back at twice the recording speed, and Figure 2 (B) shows 12 tapes. FIG. 2 is a diagram schematically showing a reproduced portion of a scanning line recorded on a track of FIG.

In FIG. 2(A), the numbers inside the box indicate the track numbers of source frame 1, the numbers inside Δ show the track numbers of source frame 2, and the numbers inside the box show the track numbers of source frame 3. The interleaving pattern of source frame l is as shown in fJS1 diagram (A),
The interleave pattern of source frame 2 is shown in Figure 1 (
As shown in B). That is, in the first track of source frame 2, the scanning line recorded in the third track of source frame 1 is recorded in a state shifted by 9 lines. Similarly, in the first track 1 link of source frame 3, the scanning line recorded in the fifth track of source frame I is recorded after being shifted by 18 lines.

The shaded area in FIG. 2(A) indicates a reproducible area, and a video signal for one frame is formed from the reproduced signals of source frame 1 and source frame 2. As is clear from FIG. 2(B), the number of types of scanning lines included in the reproduced video signal for one frame reproduced in this way is twice as many as in the case where each frame interleave rule is the same. . Note that since this example assumes digital recording and reproduction, only data in areas where the ratio of the hatched area to the track width is 60% or more can be reproduced. Although not shown, similar results can be obtained if the playback speed is set to an integral multiple of the recording speed, such as 3x playback or 6x playback.

Next, the effects of shifting the arrangement of scanning lines within a track will be explained using FIGS. 3(A), (B), (C), (D), and (E). Figure 3 (A), (B), and (C) are 2x, 3x, 6x
This is a diagram showing the head trace pattern of each track during double-speed playback, where the shaded area is the area traced by the playback head, (I) is the area where the playback video signal is obtained, and (II) is the area where the playback head traces.
) is an area where no playback video signal can be obtained. When playing at an integer multiple speed or when the number of tracks per frame is P (
2/P), the trace pattern of each track pattern becomes common.

When the track arrangement of each frame is switched as described above, the number of types of scanning lines included in the reproduced video signal for one frame increases, or since all tracks are reproduced with the same trace pattern, all If the arrangement of the scanning lines of the track matches the arrangement of the scanning lines on the screen, only the scanning lines within a limited area on the screen will be reproduced.

FIG. 3(D) is a schematic diagram showing the correspondence between tracks and screens, and the area to be reproduced during 6x speed reproduction is indicated by diagonal lines. In other words, it is possible to obtain information on scanning lines included in odd-numbered areas among areas (1) to (11) on the five screens, but information on scanning lines included in even-numbered areas cannot be obtained. In Figure 3 (D), the numbers shown on the left side indicate each area (1
) to (11) is the number of scanning lines on the l track.

In this embodiment, the arrangement of the scanning lines of each track is shifted by 9 lines for each frame. As a result, if areas (1) to (11) on the screen are arranged for the track of the first source frame as shown in FIG. 3(D), the area on the screen of each track in the next source frame is is shown in Figure 3 (
They will be arranged as shown in E). In other words, if the reproduced signal of the first source frame consists of information of scanning lines in odd-numbered areas, the second
The reproduced signal of the source frame becomes the information of the scanning line of the even-numbered area.

Here, in this embodiment, the number of shifts of scanning lines due to frame switching is set to 9, which is a shift number suitable for the above-mentioned 6x speed reproduction. Therefore, in order to ensure good reproduction at other reproduction speeds, it is desirable to set an appropriate shift number. However, in general, if you set the shift number corresponding to the highest playback speed, you can play back the scanning line information of all areas over several frames even at lower playback speeds. For example, 2x, 3x ,6
It is difficult to realize an interleave pattern that is suitable for all double-speed playbacks, both in terms of hardware and system configuration, and is not a desirable mode. The above-mentioned shift number is set to a number suitable for 6x speed playback based on the playback device.

Note that this shift number corresponds to each playable area CI of each track)
When the number of scanning lines in each non-reproducible area (II) is A, and the number of scanning lines in each non-reproducible area (II) is B, it is given by (A+B)/2.

Next, a configuration for realizing recording as in this embodiment will be explained using FIG. 4.

In the figure, 1 is an input terminal for a video signal, 2 is an A/D converter for digitizing an analog video signal, and 3 is a frame memory capable of storing video signals for two frames. The system control circuit 12 receives the digital video signal from the A/D converter 2, and increments internal frame count data F every one frame. This data F is (P
/2), it is reset and the address control circuit lO
is supplied to The address control circuit 10 determines the number of tracks to be shifted according to this data F, and accordingly sets the write address WAI and read address RAI to the memory 4.
Determine. As a result, the arrangement of tracks in the frame memory 3 is replaced.

Further, the system control circuit 10 increments the internal data T every time data for one track is derived from the memory 3, and when this data T exceeds (n/9), it is reset and supplied to the address control circuit 11. . Memory 4 is 2
A memory that can store video signals for tracks, and determines the data arrangement of each track. That is, the address control circuit 11 operates according to the data T, and the write address W
A2. By determining the read address RA2, the arrangement of each track is replaced.

Data that has been interleaved in this way is ECC
After an error correction code (ECC) is added in the addition circuit 5 and a synchronization code is added in the synchronization addition circuit 6, the modulation circuit 7 digitally modulates the tape 9.
recorded above.

In the example shown in Fig. 4, it is shown that one system of signals is recorded, but for example, when using a head with the configuration shown in Fig. 6, two systems of signals will actually be recorded. Two systems of processing circuits for frame memories 3 and below are required.

In addition, in Figure 4, whether the track arrangement swapping, the data arrangement swapping within a track, and the addition of ECC are performed in separate blocks, or in the case of an actual hardware configuration, these scans are performed in a common block. It is natural to realize this by controlling access to memory and write/read addresses.

As mentioned above, in the embodiment described using FIGS. 1 to 4, it has become possible to dramatically improve the reproduced image quality compared to the conventional art, especially when performing integer multiple speed reproduction.

Next, another embodiment will be described with reference to FIG. 5. This embodiment is particularly effective when applied to a digital VTR that performs recording and reproduction using a bare head as shown in FIG.
The operation of exchanging the track arrangement for each frame is the same as in the embodiment described in FIGS. 1 to 4.

In this embodiment, the method of arranging data on each track is different from the above-described embodiment. That is, in this embodiment, the arrangement of scanning lines recorded on even-numbered tracks is shifted on the screen with respect to the arrangement of scanning lines recorded on odd-numbered tracks.

As shown in Figure 5, the odd numbered track and even numbered track are approximately 9.
It has shifted by p duties. This corresponds to 1/2 the pitch of the reproducible area during 6x speed reproduction shown in FIGS. 3(D) and 3(E).

When recording and reproducing are performed using a device having a head arrangement as shown in FIG. 6, adjacent odd-numbered tracks and even-numbered tracks are simultaneously reproduced. These reproducible areas are located at the same position in the longitudinal direction of the track. Therefore, if the scanning lines recorded at the same position in these adjacent tracks are shifted by 9 lines, that is, by 9p lines in each track, the same effect as in the embodiment shown in FIGS. 1 to 4 can be obtained.

In each of the above-mentioned embodiments, the head arrangement was explained as being as shown in FIG.
Even if the present invention is applied to a digital recording/reproducing apparatus of the type in which a tape is wound over an angular range of 180" or more around a rotating drum equipped with four rotating heads whose rotational phase is shifted by 0 degrees, the same result can be obtained. You can get some effect.

[Effects of the Invention] As explained above, the video signal recorded by the video signal recording device of the present invention can be reproduced evenly on a large number of pixels on the screen during playback at various playback speeds. An extremely good reproduced image can be obtained.

[Brief explanation of drawings]

1A and 1B are diagrams schematically showing recording patterns of video signals by a video signal recording device as an embodiment of the present invention, and FIGS. ) is a diagram schematically showing how a tape recorded with a pattern like this is played back at twice the recording speed. Figure 2 (B) is a diagram schematically showing the reproduced portion of the scanning line of one frame. Figure 3 (A) (B) (C) (D) (E) is the arrangement of the scanning lines in the track. FIG. 4 is a diagram showing a configuration for realizing the recording pattern as shown in FIG. 1. FIG. FIG. 6 is a diagram schematically showing a recording pattern of a video signal by a signal recording device. FIG. 6 is a diagram showing the head configuration of a general digital VTR. FIG. 7(A) is a diagram schematically showing a trace pattern on a tape by the head configured as in FIG. 6, and FIG. 7(B) is a diagram schematically showing data reproduced according to FIG. 7(A). It is a diagram. In the figure, 3 is a frame memory, 4 is a track memory, 5 is an ECC addition circuit, 8 is a magnetic head, 9 is a tape, 10.
11 is an address control circuit, and 12 is a system control circuit.

Claims (2)

[Claims] (1) A device that records a video signal while forming a plurality of tracks for each screen, which switches the arrangement of the plurality of tracks in which predetermined pixels are recorded for each screen, and
A video signal recording device characterized in that the correspondence between the position of a pixel in each track on a screen and the position on the track is switched on a track-by-track basis. (2) A video signal recording device according to claim (1), characterized in that it has a function of playing back at an integral multiple of the recording speed.