JPH11164242A - High-speed reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a natural reproduced image in a high-speed reproduction device that has four heads placed on a cylinder at an angular interval of 90-degree and reproduces video data recorded on a magnetic tape at a high speed. SOLUTION: A tape drive speed by a magnetic tape drive section 2 is set to be a multiple of (M+α)/(2n+1) in the cue operation and to be a multiple of (M-α)/(2n+1) in the review operation, where M is the number of tracks equivalent to one frame, α is a predetermined constant (-0.1M<=a<=0.1M) and n is an integer made than zero. Since the scanning loci of positive azimuth heads 4a, 4c and negative azimuth heads 4b, 4d equivalent to an image at high speed reproduction are close to each other in this way, a time difference of reproducing adjacent areas on the image is reduced and then the quality of the reproduced image at high speed reproduction is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed reproducing apparatus for reproducing and outputting an image at a speed higher than a normal speed used in a digital video tape recorder or the like.

[0002]

2. Description of the Related Art In recent years, with the development of magnetic recording / reproducing technology and high-efficiency compression technology of image data, digitalization of video tape recorders has been advanced. In these devices, not only normal recording and reproduction but also high-speed reproduction operation is required as realized by an analog video tape recorder. However, in general, in a tape recording / reproducing method using helicopter scanning of compressed digital image data, image quality of high-speed reproducing operation is not desirable, and improvement of the image quality is an important issue. Therefore, many improvement proposals have already been submitted, and they can be broadly classified into two types: a system for recording special data for high-speed reproduction, and a system for high-speed reproduction using only data for normal recording and reproduction.

Here, a description will be given of a method for high-speed reproduction using only data for normal recording and reproduction related to the present invention. In this high-speed reproduction method, the data at the same time is made adjacent to each other on the screen by rearranging data called shuffling and de-shuffling, thereby improving the image quality of high-speed reproduction. There is a method (Japanese Patent Laid-Open No. 5-252476, Japanese Patent Laid-Open No. 5-266597, or the like) that expands only possible basic data portions to achieve compatibility with the image quality of normal reproduction. This method does not require special hardware for generating and recording high-speed reproduction-specific data. As a standard of a digital video tape recorder adopting the latter method, HD Digital VCR
FERENCE) Specification of Consumer Use Digital VCRs Using 6.
3mm magnetic tape (Specification of C
onsumer-Use Digital VCRs Using 6.3mm Magnetic Tap
e) (hereinafter abbreviated as DVC format) has been proposed.

Hereinafter, the DVC format (SD mode)
A conventional example of a basic high-speed reproducing apparatus based on the above will be described. FIG. 8 is a configuration diagram showing the configuration of this conventional high-speed playback device. In FIG. 8, a magnetic tape 1 is driven by a magnetic tape driving unit 102 which can be driven at normal speed and high speed, and is scanned by a pair of heads 4e and 4f of a cylinder 103. Is input to the error correction unit 5 through The correction output of the error correction unit 5 is stored in the memory 7 via the capture selection switch 6 that opens and closes according to the correction result. The data block selected and read from the memory 7 is subjected to decompression processing by the decompression processing unit 8, then temporarily stored in the output memory 9, and is output as an image from the terminal B.

[0005] In the conventional high-speed reproducing apparatus configured as described above, the recording form on the magnetic tape 1 will be described first, and then the high-speed reproducing operation (hereinafter, the forward high-speed reproducing operation will be referred to as a cue operation, the reverse direction will be described below). (The high-speed reproduction operation is abbreviated as a review operation).

In this conventional example, the recording form of the magnetic tape 1 is based on the DVC format (SD mode) described above. First, referring to FIGS.
The correspondence between the recording mode of the image and the output image will be described. FIG. 9 is a shape diagram showing a recording form of the magnetic tape 1. One frame of image data is composed of 1350 data blocks, and is recorded on the magnetic tape 1 by being divided into ten tracks as shown in FIG. Each track contains 135 data blocks. The data block (0, 1) in the drawing means the first data block on the 0th track.

FIG. 10 is a structural diagram showing the structure of a screen of one frame. In FIG. 10, a screen of one frame is divided into rectangular areas called 1350 macroblocks, and each macroblock corresponds to a data block on the magnetic tape 1 in FIG. In addition, 135 data blocks recorded on each of tracks 0 to 9 on the magnetic tape 1 are displayed on the screen in FIG.
As shown by 0, it corresponds to a macroblock aligned in one band-like area.

[0008] With such a configuration, since data to be reproduced simultaneously at the time of high-speed reproduction is solidified and continuous on the screen, an easily viewable image quality can be obtained even at high-speed reproduction using only data for normal recording and reproduction.

Next, as an operation of the conventional example (SD mode),
The queue operation will be described. Now, it is assumed that the magnetic tape driving unit 102 drives the magnetic tape 1 at a speed of 10.5 times the normal speed, and the rotation speed of the cylinder 103 is the same as that in the normal reproduction. FIG. 11 shows the head 4
e, two scan loci drawn on the magnetic tape 1 by the center point of the head 4f. In FIG. 11, the trajectory of the head 4e is drawn by a half rotation of the cylinder 103, and the trajectory of the head 4f is drawn by a subsequent half rotation of the cylinder 103. Since the drive speed of the magnetic tape 1 is 10.5 times, one head locus is 10.5-1 = 9.
The track crosses five tracks, and the track number corresponding to the start position of each scan is 10.5-10 = 0.
5, that is, it increases by 0.5. Assuming that even-numbered tracks among the tracks on the magnetic tape 1 have a plus azimuth angle and odd-numbered tracks have a minus azimuth angle, the head 4e has a plus azimuth angle, and the head 4f has a minus azimuth angle. 11
In the two scans shown in (1), the data blocks indicated by hatching from the magnetic tape 1 are reproduced.

The error correction unit 5 receives the reproduced data block, performs error correction processing in data block units, and takes in the corrected data block and sends it to the selection switch 6. If the reliability of the corrected data block after processing is sufficient, the capture selection switch 6 is turned on. If it is determined that the reliability is lacking, the capture selection switch 6 is turned off.
Is turned off. That is, only the data blocks that have been subjected to the error / error correction processing are stored in the memory 7 via the selection switch 6 without error.

FIG. 12 is a distribution diagram of data blocks stored in the memory 7. FIG. 12 is drawn in association with the positional relationship of the screen as in FIG. Reproduced data blocks obtained by two scans of two frames shown in FIG. 11 are shown on the memory 7 at the positions indicated by the numerals in FIG. Stored in the area. The number struck here in the area,
Here, 1 or 2 indicates the frame number to which the reproduced area belongs. Further, by repeating the scan 20 times, the data is stored in the entire area of FIG. 12, and the data of one entire frame is updated on the memory 7. Further, the band-shaped area updated each time scanning is performed is moved downward and upward by 0.5 track width on the screen.

The decompression processing unit 8 sequentially reads out data blocks from the memory 7, performs decompression processing, and transfers image data as a decompression result to the output memory 9. Then, the images are sequentially output from the output memory 9 via the terminal B.

As described above, in the conventional queue operation, the error correction unit 5 writes a data block on a single surface of the memory 7 and the decompression processing unit 8 reads the same surface, whereby image-compressed recording is performed. In spite of the operation of obliquely scanning the magnetic tape 1 over a plurality of tracks, the data block reproduced using the memory 7 is reconstructed, and the data at the same time is arranged in a close portion on the screen. High-speed playback images can be output.

Next, a description will be given of a high-speed reproduction operation in the HD mode, which is defined as the upper mode of the SD mode in the DVC format. The HD mode enables recording and reproduction of images with higher precision by setting the recording rate to twice that of the SD mode. Specifically, in the SD mode, the current television broadcast signal is used, and
In the D mode, an HDTV signal is recorded and reproduced.

First, the correspondence between the recording mode of the magnetic tape 1 and the output image in the HD mode will be described with reference to FIGS. FIG. 2 is a shape diagram showing a recording form of the magnetic tape 1 in the HD mode. Recording rate is 2 for SD mode
Therefore, one frame of image data is composed of 2700 data blocks. Then, on the magnetic tape 1, as shown in FIG. The number of data blocks included in each track is 135, which is the same as in the SD mode.

FIG. 3 is a structural diagram showing a structure of a screen of one frame. In FIG. 3, the screen of one frame is divided into rectangular areas called 2700 macroblocks, and each macroblock is divided into the magnetic tape 1 shown in FIG.
Corresponds to the upper data block.

FIG. 13 shows such a tape format recording / reproducing apparatus. In this recording / reproducing apparatus, the configuration of the cylinder, the head, and the magnetic tape drive unit 112 must be changed from the SD mode. In the DVC format, the relative speed of the head-tape is determined by the SD mode and HD mode.
In order to double the recording rate, it is necessary to mount four heads twice as much as in the mode, and furthermore, double the tape feed speed during normal recording and reproduction in the SD mode. For how to arrange the four heads on the cylinder,
Although there are several methods, usually, four heads 4 to 4d are arranged on the cylinder 3 every 90 degrees as shown in FIG. Of these heads, heads 4a and 4c have a positive azimuth, and heads 4b and 4d have a negative azimuth. The operation of the remaining part in FIG. 13 is the same as in the SD mode, except that the tape feed speed during normal reproduction of the magnetic tape drive unit 112 is twice that in the SD mode, and thus the description is omitted.

Next, a cue operation in the HD mode will be described. Now, as in the SD mode, the magnetic tape driving unit 2 drives the magnetic tape 1 at a speed 10.5 times the normal speed, and the rotation speed of the cylinder 3 is the same as that in the normal reproduction. And FIG. 14 shows the head 4
The center points of a, 4b, 4c, and 4d indicate the scan loci drawn on the magnetic tape 1. In FIG. 14, the head 4a
Is drawn by half rotation of the cylinder 3, and the trajectory of the head 4b is drawn by half rotation of the cylinder 3 starting with a delay of 90 degrees from the start of scanning of the head 4a. The heads 4c and 4d are sequentially scanned similarly. Since the driving speed of the magnetic tape 1 is 10.5 times, one head locus is 2 × (10.5
-1) = 19 tracks are traversed, and the track number corresponding to the start position of each scan is increased by 10.5. Similarly to the SD, the tracks on the magnetic tape 1 are generated with an even-numbered track at a plus azimuth angle and the odd-numbered tracks at a minus azimuth angle, so that the scanning shown in FIG. That is, the data block of the part that has been reproduced is reproduced.

FIG. 15 is a distribution diagram of data blocks stored in the memory 7. Reproduced data blocks obtained by the four scans shown in FIG. 14 are shown on the memory 7 at the positions indicated by the numerals in FIG. Stored in the area. Unlike the SD mode, there are two types of this band-like area, one based on a combination of the plus azimuth heads of the heads 4a and 4c, and the other based on a combination of the minus heads of the heads 4b and 4d. The belt-shaped area moves downward by one track on the screen for each of the plus-azimuth and minus-azimuth belt-shaped areas. That is, when looking at the screen during the cue operation, it appears that a plurality of downward-sloping strip-shaped areas are moving downward on the screen.

[0020]

SUMMARY OF THE INVENTION
The problem at the time of high-speed reproduction in the D mode will be described. As described above, since azimuth recording is performed, even tracks among tracks are plus azimuth heads (4a, 4c),
Odd track is minus azimuth head (4b, 4d)
You can only play data with. Now, in FIG. 15, attention is paid to the regions x and y shown in the tracks 4 and 5. First, the region x is reproduced without any problem by the scanning by the head 4a. Next, an area y adjacent to the area x
However, the head 4c scans the vicinity of the next frame in the next frame, but cannot reproduce due to a different azimuth.
Reproduction of the area y is limited to the head 4b or 4d. Now, the scanning positions of the heads 4b and 4d deviate considerably from the scanning locus of the head 4a as shown in the figure. As described above, since the belt-like area is sequentially moving down the screen, the area y will eventually be scanned by the head 4b or 4d, and data will be reproduced at that time. Thus, in this conventional configuration, there is a time lag at the time when the area x and the area y are updated. Specifically, the area y is updated only when the area x is updated and the number of frames is changed. 10 frames or more later. In other words, data that has an extremely long time difference is played back even though they are adjacent on the screen, and especially when fast-moving moving images are played at high speed, the way the screen is updated becomes very unnatural. Had the problem that

An object of the present invention is to improve the way in which an image is updated in a high-speed reproducing apparatus using four heads arranged at 90 degrees on a cylinder.

[0022]

According to a first aspect of the present invention, there is provided a cylinder having a cylinder and two heads mounted on the cylinder at intervals of 90 degrees and opposed to each other by 180 degrees. , The first set is plus azimuth angle, the other second
Set consists of four heads with minus azimuth angle,
The tape-shaped recording medium on which the image data of the surface is divided into M tracks and recorded is run around the cylinder, and at the time of high-speed reproduction, M / (2
(n + 1) (n is an integer equal to or greater than 0).

According to a second aspect of the present invention, there is provided a cylinder, and two heads mounted on the cylinder at intervals of 90 degrees and facing each other by 180 degrees. Group 2 is composed of four heads having a minus azimuth angle, one surface of image data divided into M tracks, and a recording medium on a tape recorded in units of a plurality of blocks on each track is run, and high-speed reproduction is performed. Time is k for normal playback
M / (2n + 1) (n is an integer of 0 or more, 0.9 ≦ k ≦
1.1) tape driving means for driving at twice the recording medium transfer speed, and reproducing data read from the head,
Error correction means for performing error correction processing, memory for holding read data in units of blocks after error correction by the error correction means in an area corresponding to one-sided image data, and reading and expanding the output of the memory in units of one screen And a decompression processing unit for performing processing.

The invention of claim 3 of the present application is directed to claim 1 or 2
In the high-speed reproducing apparatus according to (1), the tape driving means sets a predetermined constant to α (−0.1M ≦ α ≦ 0.1
M), (M + α) / (2n + 1) times the normal reproduction during forward high-speed reproduction, and (M−α) / (2n + 1) times (n is 0) during the normal high-speed reproduction during normal reproduction.
It is characterized by being driven at a recording medium transfer speed of (the above integer).

By setting the tape speed in this manner, the scanning trajectory of the plus azimuth head and the minus azimuth head in the playback screen can be made close to each other, and the time difference between adjacent areas on the screen can be reduced and playback can be performed. can do.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the configuration of a high-speed reproducing apparatus according to this embodiment will be described. The basic configuration of the high-speed playback device according to this embodiment is the same as that of the above-described conventional example. That is, in FIG. 1, the magnetic tape 1 is driven by a magnetic tape driving unit 2 that drives the magnetic tape 1 at high speed. Also cylinder 3
Has four heads arranged in the cylinder at 90 ° intervals. Of these heads, heads 4a and 4c are 18
It faces 0 degrees and has + azimuth. The heads 4b and 4d are opposed to each other by 180 degrees, and are heads having a minus magic angle. The signals read from these heads are input to the error correction unit 5. The correction output of the error correction unit 5 is a capture selection switch 6 that opens and closes according to the correction result.
Through the memory 7. The data block read from the memory 7 is subjected to decompression processing by the decompression processing unit 8 and then temporarily stored in the output memory 9 and read from the output memory 9.

Here, it is assumed that the magnetic tape driving section 2 according to the present embodiment runs the tape at the following speed with respect to the running speed at the time of recording and at the time of reproduction at the normal speed. When one frame of image data is divided into M tracks and stored, the reproduction speed is M / (2n +
1) (n is an integer of 0 or more) Drive at a recording medium transfer speed that is about multiple times. That is, if one frame is composed of 20 frames as shown in FIG.
Drive at a speed near 6.66 times, 4.times., 2.86 times...

Thus, the scanning trajectories of the plus azimuth head and the minus azimuth head in the reproduction screen can be brought close in time and distance. That is, since the adjacent area on the screen can be reproduced with a small time difference, the quality of the reproduced image at the time of high-speed reproduction can be improved.

With respect to the high-speed reproducing apparatus of the present invention having the above-described configuration, a high-speed reproducing operation (queue operation) in the forward direction,
The high-speed reproduction operation (review operation) in the reverse direction will be sequentially described below.

First, the queue operation will be described. The present embodiment differs from the conventional HD mode high-speed playback apparatus in the drive speed of the magnetic tape drive unit 2 during cueing. That is, as shown in FIG. 2, a screen of one frame is divided into 20 tracks from track number 0 to track number 19 and recorded. Data blocks of each track are composed of 135 blocks, and one frame is composed of 2700 data blocks. Constitute. As described above, the tape driving unit 2 drives the magnetic tape 1 at a speed near 20 / (2n + 1) with respect to the normal speed, for example, at a speed of (20 + α) / 3. If α is, for example, 0.5, the tape drive speed is 6.
83 times. It is assumed that the rotation speed of the cylinder 3 is the same as that in the case of normal reproduction.

FIG. 4 shows that the center points of the heads 4a, 4b, 4c and 4d when the tape is run at this driving speed are as follows.
2 shows a scanning locus drawn on the magnetic tape 1.
In FIG. 4, the trajectory of the head 4a is drawn by a half rotation of the cylinder 3, and the trajectory of the head 4b is drawn by a half rotation started from the time when the scanning of the head 4a is delayed by 90 degrees of the cylinder 3. As a result of driving at 6.83 times speed, one head trajectory crosses 2 × (6.83-1) = 11.7 tracks, and the track number corresponding to the start position of each scan is: It will increase by 6.83.

FIG. 5 is a distribution diagram of data blocks stored in the memory 7. In this figure, a line drawn from the upper left to the lower right indicates a scan line stored in the memory 7 by scanning of the head 4a, and the numerical value given to the track included on this line indicates the data of the first frame. I have. The head 4b starts scanning from a position separated by 6.83 tracks, and the head 4c starts scanning from a position further separated by 6.83 tracks, that is, 13.66 tracks. Read the data of the frame. Therefore, the head 4d starts scanning from 20.49 tracks, that is, a position shifted by about 0.5 tracks in the original second frame. The data blocks obtained in each scan are stored in the lower right band-like area shown in FIG. As shown in the drawing, a plurality of band-shaped regions are formed on a screen for a certain frame. Then, each of the belt-shaped areas moves downward by 0.5 track every time the head scans one frame. Decompression processing unit 8
Reading data from the memory 7 and outputting a high-speed playback video via the output memory 9 is exactly the same as in the conventional example.

Now, in the image reproduced in this way,
How the conventional problem is solved will be described. As in the conventional example, attention is paid to areas u and w of adjacent tracks as shown in FIG. In the first frame, first, the area u is scanned by the head 4a and reproduced. The area w is
In the subsequent second frame, scanning is performed by the head 4d. In the conventional example, since the heads 4a and 4c have the same azimuth angle, this area w cannot be reproduced by the head 4c. However, in this embodiment, since the heads 4a and 4d have reverse azimuths, the area w has a problem due to the head 4d. It is possible to reproduce without. That is, in the frame immediately following the frame in which the area u has been reproduced, the area w is also reproduced.
As a result, when viewed on the screen, adjacent areas are reproduced almost simultaneously, and a very natural reproduced image can be obtained during high-speed reproduction.

Next, the review operation will be described. At the time of review, the drive speed is set to (20-α) / 3 times. α
Assuming that = 0.5, specifically, it becomes 6.5 times. The head 4 when the magnetic tape driving unit 2 drives the magnetic tape 1 in reverse running at 6.5 times the normal speed
FIG. 6 shows scan loci drawn on the magnetic tape 1 by the center points a, 4b, 4c, and 4d. One head trajectory is 2
× (6.5 + 1) = 15 tracks, and the track number corresponding to the start position of each scan is reduced by 6.5. That is, assuming that the trajectory of the head 4a starts from the lower left end of FIG. 7, 6.5.
The scanning of the head 4b starts from the position shifted by 13 frames and the head 4c starts from the position shifted by 13 frames. Therefore, the head 4d starts scanning from 19.5, that is, a position close to the locus of the head 4a. As described above, FIG. 7 is a distribution diagram of the data blocks stored in the memory 7. As in the case of the cue operation, the data blocks are stored in a plurality of upward-sloping belt-like areas as shown in FIG. In addition, each of the band-shaped areas moves downward by 0.5 track every frame scan.

In this review operation, similarly to the cue operation, the trajectory of the plus azimuth head and the trajectory of the minus azimuth head can be brought close to each other on the screen, so that adjacent areas can be reproduced with a time difference of one frame. Thus, a natural high-speed reproduction image can be obtained.

Here, in the speed setting at the time of the review operation, -α is used instead of + α. In this way, by setting + α at the time of the cue operation and −α at the time of the review operation,
In both the case of the cue operation and the case of the review operation, the band-shaped area updated in the memory 7 moves downward by 0.5 track every one frame scan of the head. That is, for each scan of one frame, in the cue operation and the review operation, the movement of the position of the data to be written on the memory is in the same direction and the movement amount is the same. Therefore, the sequence of the screen output from the memory 7 is the same between the cue operation and the review operation, and an output video of substantially the same image quality can be obtained.

In the present embodiment, α is set to a value of +0.5, but the same effect can be obtained even if the value is minus. That is, the speed setting may be (20-0.5) /3=6.5 times speed in the cue operation, and (20 + 0.5) /3=6.83 times speed in the review operation. In this case, the moving amount of the band-shaped area trajectory of the screen for each frame is 0.5 track upward in both the cue operation and the review operation.

In the description of this embodiment, the speed in the case of the constant n = 1 in the claims is described. However, if n is an integer of 0 or more, the condition is satisfied. Specifically, when M = 20, similar effects can be obtained by performing cue and review operations near a speed such as 20 × speed (n = 0) and 4 × speed (n = 2). However, if the speed is M / (2n + 1) itself, only the same portion is scanned, and an image of one frame cannot be formed on the memory 7, so that a normal screen cannot be viewed. Here, the vicinity is a speed at which an image of one frame can be formed at an appropriate speed, for example, kM / (2n + 1).
And k is in the range of 0.9 to 1.1. The aforementioned α is 0.5 or −0.5 within this range, but α can be changed within a range of ± 10% of M to satisfy this requirement.

[0039]

As described above, according to the present invention, since the scanning trajectories of the plus azimuth head and the minus azimuth head in the playback screen are brought close to each other during high-speed playback, the time difference between adjacent areas on the screen is reduced. And can be played. Therefore, the effect that the quality of the reproduced image at the time of high-speed reproduction can be improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a high-speed playback device according to an embodiment of the present invention.

FIG. 2 is a shape diagram showing a recording form of a magnetic tape 1 in an HD mode.

FIG. 3 is a structural diagram showing a structure of a screen of one frame in an HD mode.

FIG. 4 is a shape diagram showing a scan trajectory of a center point of a head in a cue operation (HD mode: 6.83 times).

FIG. 5 is a structural diagram of data stored in a memory 7 in a cue operation (HD mode 6.83 times).

FIG. 6 is a shape diagram showing a scan locus of a center point of a head in a review operation (HD mode 6.5 times).

FIG. 7 is a structural diagram of data stored in a memory 7 in a review operation (HD mode 6.5 times).

FIG. 8 is a configuration diagram of a conventional SD mode high-speed playback device.

FIG. 9 is a shape diagram showing a recording form of the magnetic tape 1 in the SD mode.

FIG. 10 is a structural diagram showing a structure of a screen of one frame in an SD mode.

FIG. 11 is a shape diagram showing a scan trajectory of a center point of a head in a cue operation (SD mode 10.5 × speed).

FIG. 12 is a structural diagram of data stored in a memory 7 in a queue operation (SD mode 10.5 × speed).

FIG. 13 is a configuration diagram of a conventional HD mode high-speed playback device.

FIG. 14 is a shape diagram showing a scan locus of a center point of a head in a cue operation (HD mode, 10.5 × speed).

FIG. 15 is a structural diagram of data stored in a memory 7 in a queue operation (HD mode 10.5 × speed).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic tape 2 Magnetic tape drive part 3 Cylinder 4a, 4b, 4c, 4d Head 5 Error correction part 6 Capture selection switch 7 Memory 8 Decompression processing part 9 Output memory

Claims (3)

[Claims] 1. A cylinder, comprising two heads mounted at 90 ° intervals on the cylinder and opposed by 180 °, a first set having a positive azimuth angle, and a second set having a negative azimuth angle. And a tape-shaped recording medium in which image data of one surface is divided into M tracks and recorded is run around the cylinder, and during high-speed reproduction, during normal reproduction M /
(2n + 1) (n is an integer greater than or equal to 0) a tape drive unit driven at a recording medium transfer speed that is about twice as high. 2. A cylinder, comprising two heads mounted at 90 ° intervals on the cylinder and facing each other by 180 °, a first set having a positive azimuth angle and a second set having a negative azimuth angle. And four heads having the following formulas: one surface of image data is divided into M tracks, and a recording medium on a tape in which a plurality of blocks are recorded in each track is run on each track; / (2n +
1) (n is an integer of 0 or more, 0.9 ≦ k ≦ 1.1) a tape driving unit that drives at a recording medium transfer speed that is times as high, and reproduces data read from the head to perform error correction processing. Error correcting means for performing, a memory for holding read data in units of blocks after error correction by the error correcting means in an area corresponding to one-sided image data, and a decompression for reading and expanding the output of the memory in units of one screen. A high-speed playback device comprising: a processing unit. 3. The tape driving means according to claim 1, wherein when a predetermined constant is α (−0.1 M ≦ α ≦ 0.1 M), (M + α) /
(2n + 1) times, (M−α) / (2n + 1) times (n is an integer of 0 or more) at the time of normal reproduction in normal reproduction.
3. The high-speed reproducing apparatus according to claim 1, wherein the high-speed reproducing apparatus is driven at a recording medium transfer speed.