JP3267001B2 - Recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus, and more particularly to a digital VTR.

[0002]

2. Description of the Related Art Conventionally, analog recording has been used for VTR. However, VTR based on digital recording is now expected because VTR based on analog recording suffers remarkable image quality deterioration due to recording and reproduction, especially dubbing.

FIG. 9 shows an example of a block diagram of a general home digital VTR. 101 is an error correction encoder, 10
2 is a modulator, 103 is a recording head, 107 is an error correction decoder, 106 is a demodulator, 105 is a reproducing head, and 104 is a magnetic tape.

At the time of recording, an input video signal is input to an error correction encoder 101. Error correction encoder 10
In step 1, an error correction code is added to the input video signal, and the resultant signal is output to the modulator 102. The modulator 102 modulates the input data and outputs the data to the recording head 103.
The recording head 103 records the modulated data on the magnetic tape 104.

At the time of reproduction, reproduction data is input from a magnetic tape 104 to a demodulator 106 by a reproduction head 105. The demodulator 106 demodulates the reproduced data and outputs the demodulated data to the error correction decoder 107. Error correction decoder 107
Then, an error in the reproduced data is corrected and a video signal is output.

[0006] The video signal and the audio signal are recorded and reproduced as described above. Helical recording is used in VTRs. This is a recording / reproducing method in which a head 112 is mounted on a cylinder 111 inclined with respect to a vertical direction as shown in FIG. 10, rotated at high speed, and a magnetic tape 113 is wound around a loading post 114 and run as shown in FIG. .

By performing the helical recording, the data is recorded as a track 115 as shown in FIG. 12 from the running of the magnetic tape 113 and the rotation of the head 112.

[0008] The search is realized by setting the speed of the magnetic tape 113 higher than that during normal reproduction. At this time, since the speed of the magnetic tape 113 increases, the locus of the head 112 crosses a plurality of tracks as indicated by arrows in FIG. When crossing a truck, the truck 115
If the azimuth angle of the head 112 is the same as that of the head 112, the data in the traversed portion is reproduced (shaded portion in FIG. 13), and by decoding this data, the video can be reproduced.

[0009]

However, at the time of search, it is impossible to reproduce all the data recorded at the time of recording, so that the image quality deteriorates.

[0010] In addition, since the magnetic tape runs at a high speed during the search, the reproducible data is updated in order over a plurality of frames without updating the screen all at once, making it difficult to see the screen.

When the recorded video is recorded by variable-length coding, the position on the magnetic tape does not correspond to the position on the screen, so that the order in which the screen is updated during the search is not constant. . For this reason, pixels that are not updated may appear on the screen, and in this case, the screen becomes difficult to see.

[0012] In addition, the information to be recorded can be reduced by recording a difference between a video compressed in one frame and the video without recording the video as it is, and recording the video compressed between frames. In this method, in order to restore a video that has been compressed between frames, information on the video that has been compressed within the frame, which is the source of the difference, is required, but this is not reliably reproduced during the search. Therefore, in the video using inter-frame compression, the video that can be restored at the time of search is only the intra-frame compressed data among the reproduced data. At this time, all the reproduced data cannot be restored to the image.

An object of the present invention is to solve the above problems and to provide a recording / reproducing apparatus having excellent image quality at the time of searching.

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a search data encoding means which uses a video signal input as search data and a plurality of search data identical data over n tracks. And a format means for rearranging the data to be recorded.

[0015]

According to the present invention, a search data encoding means for using a video signal input as search data and a format means for rearranging the search data so that a plurality of pieces of the same data are recorded over n tracks are provided. Sometimes it works to output images with excellent image quality.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment according to the recording / reproducing apparatus of the present invention. At the time of recording, the video signal is encoded with search data by the search data encoder 1. In the case of an inter-frame compressed video signal, this search data encoding is capable of extracting a signal in a frame or compressing a video signal to reproduce a screen with less data, and can be reproduced. The screen can be reproduced even during a search with a small amount of data. The video signal is also input to the formatter 2 as it is as normal reproduction data, and is formatted together with the search data by the formatter 2 into a track pattern as shown in FIG. After the recording data is input to the error correction encoder 3, it is modulated by the modulator 4 and recorded on the magnetic tape 6 by the recording head 5.

At the time of reproduction, recorded data is reproduced from the magnetic tape 6 by the reproduction head 7 and demodulated by the demodulator 8. The demodulated data is subjected to error correction by an error correction decoder 9 and input to a deformatter 10. The deformatter 10 separates the data for normal reproduction and the data for search, and outputs the data individually. At the time of normal reproduction, the contact piece is connected to the terminal a by the switch 12,
The data for normal reproduction is output as a video output. At the time of search, the contact piece is connected to the terminal b side by the switch 12 to expand the search data that has been input to the search video decoder 11 and has been compressed and returned to the same format as that of the normal reproduction, and as a video signal Output.

Hereinafter, the time during which one frame of video is recorded during normal playback is referred to as one frame period, and the section on the magnetic tape where one frame of video is recorded is referred to as one frame section.

FIG. 2 shows an example of a track pattern formed by the formatter 2. Regions 30, 31, 3
2, 33, 34, 35, 36, 37, 38 and 39 are search data areas, and areas 20, 21, 22, 2 and
3, 24, 25, 26, 27, 28 and 29 are data areas for normal reproduction. The search data is in search data areas 30, 31, 32, 33, 34, 35, 36, 3
7, 38 and 39, and the normal reproduction data is stored in the normal reproduction data areas 20, 21, 22, 23, 24, 2
5, 26, 27, 28 and 29.

At the time of recording, one frame of normal reproduction data is recorded in one normal reproduction area. For example,
One frame of data at time n is recorded in the normal reproduction data area 21, one frame of data at time (n + 1) is recorded in the normal reproduction data area 22, and at time (n + 2). Is recorded in the normal reproduction data area 23, one frame of data at the time (n + 3) is recorded in the normal reproduction data area 24, and one frame of the time (n + 4) is recorded. Is recorded in the data area 25 for normal reproduction.

On the other hand, the search data is recorded in the search data area. At the time of the search, the tape speed is higher than at the time of the normal reproduction. For example, if the search speed is four times that of the normal reproduction, At the time of search, the magnetic tape is sent at four times, so that one frame period is four times as large as that at normal reproduction.
Play the frame section.

Therefore, the search data at the time of frame n is divided into four parts, and the search areas 31 and 3 of the four-frame section are divided.
Record at 2, 33 and 34. In the next search area, search data for frame (n + 4) is stored in the next search area.
The search areas 35, 36, 3 divided into four frame sections
Record at 7 and 38. Hereinafter, recording is performed similarly.

When the search data is large and one frame of search data cannot be recorded in the search area of four frames, for example, as shown in FIG. The video signal of is recorded. At this time, during high-speed reproduction, it is possible to reproduce one frame of video in two frame periods. Update cycle is 2
Although doubled, one screen can be updated simultaneously.

Alternatively, as shown in FIG. 4, half of one frame, for example, the right half on the screen is recorded in the search area of the first four frame sections, and the left half of the screen is recorded in the remaining four frame sections. 1 in one frame period
It is possible to reproduce half the video of the frame.

As shown in FIG. 5, consider a head configuration which is 180 degrees opposite and has a different azimuth angle. In this head configuration, if the cylinder makes one rotation when the tape traveling speed is four times the speed during normal reproduction, a head pass as shown in FIG. 6 is taken. The hatched area is the area that can be reproduced at this time. When the speed is an even multiple speed, the azimuth angles are different from each other, so that the areas that can be reproduced by the head A and the head B are different from each other. Therefore, if the same data is repeatedly recorded on a certain portion of the track, either of the two heads can always reproduce this data. Since the heads A and B complement each other to reproduce data, the same data may be recorded during each single scan. This is twice as many tracks as the search speed in the head configuration shown in FIG. 5, and becomes eight tracks at four times the speed. As described above, the same data is recorded in the search area during the section in which the cylinder makes one rotation at the even speed, ie, 2n tracks at the n speed, so that this data can be reliably reproduced. This does not change even if the head path is different.

By recording in such a track pattern, control of the head and the magnetic tape during high-speed reproduction can be simplified.

In FIG. 6, the same data (A1, A2, A3, A4, and A) are recorded over eight (= 4 × 2) tracks.
5) is recorded. If a search is performed at a quadruple speed, the heads A and B reproduce this area once. With the above data arrangement, it is possible to reproduce A1, A2, and A3 by the head A and data A4 and A5 by the head B at the time of the head pass as shown in FIG.

By recording in such a track pattern, reproducible data can be scheduled in advance.

When two heads having different azimuths are provided at one position of the cylinder, separated by one track as shown in FIG. 7, the head path is as shown in FIG. 8 at an integer +1/2 times speed. become. At this time, by recording A, B, A, B,... For each track in the search area, the data of A and B can be surely reproduced during two rotations of the cylinder.

In this embodiment, the data for normal reproduction is distinguished from the data for search. However, the data for search may be compressed data for normal reproduction or may be used as it is. Or completely different data. Also, the description has been given of the example in which the data for normal reproduction is recorded at the beginning of the track, and then the data for search is recorded. However, the data for search may be recorded first. Although the search speed is quadrupled, a higher-speed search may be used.

Although the search speed is quadrupled in the present embodiment, the same effect can be obtained when the search speed is quadrupled. When such a track pattern is determined, the track patterns of the forward search and the reverse search are the same.

In this embodiment, the track pattern is determined by fixing the search speed to four times. However, the track pattern may be formatted into a track pattern that allows a search at a plurality of search speeds. Further, although the description has been made with the head configuration fixed, the track pattern may be formatted so as to search for a different head configuration.

[0034]

As described above, the recording / reproducing apparatus of the present invention is
By providing a search data encoding unit that uses a video signal input as search data and a format unit that rearranges the search data so that a plurality of identical data are recorded over n tracks, the image quality at the time of search is improved, A stable output can be obtained, and the digital VTR
When used for a large amount, a great effect is achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a track pattern diagram recorded by the recording / reproducing apparatus of the present invention.

FIG. 3 is a track pattern diagram recorded by the recording / reproducing apparatus of the present invention.

FIG. 4 is a track pattern diagram recorded by a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 5 is a diagram showing an example of the arrangement of heads used in the recording / reproducing apparatus of the present invention.

FIG. 6 is a diagram showing a track pattern recorded by a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 7 is a view showing another arrangement example of the head used in the recording / reproducing apparatus of the present invention.

FIG. 8 is a track pattern diagram recorded by a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 9 is a block diagram of a conventional recording / reproducing apparatus.

FIG. 10 is a configuration diagram of a cylinder for performing helical recording and its head.

FIG. 11 is a configuration diagram of a main part of a tape traveling system that performs helical recording.

FIG. 12 is a track pattern diagram recorded by helical recording.

FIG. 13 is a track pattern diagram recorded by a conventional recording / reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Search data encoder 2 Formatter 3 Error correction encoder 4 Modulator 5 Recording head 6 Magnetic tape 7 Reproduction head 8 Demodulator 9 Error correction decoder 10 Deformatter 11 Search data decoder 12 Switch

Claims (5)

(57) [Claims] 1. A recording / reproducing apparatus for recording and reproducing video data composed of intra-frame compressed data and inter-frame compressed data on a track by a plurality of heads, wherein the track is composed of a normal reproduction area and a fixed special reproduction area. At the time of recording , n tracks (n is 2 or more) in the special reproduction area
Of the compressed data in the frame
Data and a part of the same compressed data in the frame during special playback.
A plurality of times, and read the same data in the same frame pressure according to the read data.
A recording / reproducing apparatus for performing special reproduction while complementing data consisting of a part of compressed data . 2. A recording / reproducing apparatus for recording and reproducing video data composed of intra-frame compressed data and inter-frame compressed data on a track by a plurality of heads, wherein the track comprises a normal reproduction area and a fixed special reproduction area. In the special reproduction area, the frame read in correspondence with the positions of the plurality of heads so as to perform the special reproduction while complementing the data read by the plurality of heads with each other.
The same data consisting of a part of the compressed data in n tracks
(N is an integer of 2 or more) . 3. A head configuration in which the plurality of heads are opposed to each other by 180 degrees, the speed during the special reproduction is an even multiple speed, the n tracks are continuous, and n is the speed during the special reproduction. 3. The recording / reproducing apparatus according to claim 1, wherein the number is twice the number . 4. The plurality of heads have a head configuration facing 180 degrees or a head configuration in which each head is separated by one track, the speed at the time of trick play is an integer +1/2 times speed , and the n tracks are continuous. 3. The recording / reproducing apparatus according to claim 1, wherein said n is four times the number of speeds during said special reproduction. 5. A head configuration in which the plurality of heads face each other by 180 degrees or a head configuration in which each of the plurality of heads is separated by one track, the speed at the time of trick play is an integer +1/2 times speed , and the n tracks have A plurality of types of the in- frame compressed data
Data consisting of a part of the data are recorded intermittently for n tracks, and n is a value in the frame.
3. The recording / reproducing apparatus according to claim 1 , wherein the speed number at the time of the special reproduction is twice as high for each type of data composed of a part of the compressed data .