JPH0795512A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide a recording and reproducing device which outputs a stable search image with high picture quality. CONSTITUTION:A video signal input is defined as data for search by a data encoder 1 for search. The video signal input is formatted and turned to recording data by a formatter 2 so as to record the same data of the data for search over (n) tracks plural times. The recording data are inputted to an error correction encoder 3, modulated by a modulator 4 later and recorded in a magnetic tape 6 by a recording head 5. At the time of reproducing, they are reproduced from the magnetic tape 6 by a reproducing head 6 and turned to data by a modulator 8. The data are inputted to a deformatter 10 while performing error correction to them with an error correction decoder 9. At the deformatter 10, the data are separated into data for normal reproducing and data for search and respectively outputted. At the time of normal reproducing, the data for normal reproducing are outputted by a switch 12. At the time of search, the data are decoded to pictures by the data decoder for search and outputted later.

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, but VTR by digital recording is currently expected because recording / reproduction, especially image quality deterioration due to dubbing is remarkable in VTR by analog recording.

FIG. 9 shows an example of a block diagram of a general home digital VTR. 101 is an error correction encoder, 10
Reference numeral 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.

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

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

Video signals and audio signals are recorded and reproduced as described above. Helical recording is used in the VTR. This is a recording / reproducing method in which a head 112 is attached to a cylinder 111 inclined with respect to the vertical direction as shown in FIG. 10, the head 112 is rotated at a high speed, and a magnetic tape 113 is wound around a loading post 114 as shown in FIG. .

By performing the helical recording, the magnetic tape 113 is run and the head 112 is rotated to record as a track 115 as shown in FIG.

The search is realized by making the speed of the magnetic tape 113 higher than that during normal reproduction. At this time, the trajectory of the head 112 takes a trajectory traversing a plurality of tracks as indicated by an arrow in FIG. 13 because the speed of the magnetic tape 113 is increased. When crossing the track, track 115
If the azimuth angle of the head 112 is the same, the data of the crossed portion is reproduced (hatched portion in FIG. 13), and the video can be reproduced by decoding this data.

[0009]

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

Further, since the magnetic tape runs at a high speed during the search, the reproducible data is not updated at once over a plurality of frames but is updated in order, which makes 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 is not constant at the time of search. . Therefore, there is a possibility that some pixels of the screen are not updated, and in this case, the screen becomes difficult to see.

Further, the information to be recorded is reduced by not recording the video as it is and by taking the difference between the video compressed within one frame and the video and recording the compressed video between the compressed frames. In the method described above, in order to restore the video compressed between frames, the information of the intra-frame compressed video that is the source of the difference is required, but this is not reliably reproduced during the search. Therefore, in the video using the inter-frame compression, the video can be restored at the time of search only for the data compressed in the frame among the reproduced data. At this time, it becomes impossible to restore all the reproduced data to an image.

An object of the present invention is to solve the above problems and to provide a recording / reproducing apparatus which is excellent in image quality during search.

[0014]

In order to achieve the above-mentioned object, the present invention provides a plurality of search data encoding means which use video signal input as search data and a plurality of the same data over n tracks. And a formatting means for rearranging so as to record.

[0015]

According to the present invention, the search data encoding means using the video signal input as the search data and the formatting means for rearranging the search data so as to record a plurality of the same data over n tracks are used. 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 of a recording / reproducing apparatus of the present invention. At the time of recording, the search data encoder 1 encodes the search data for the video signal. In the case of a video signal that is compressed between frames, this data coding for search enables to extract the signal within the frame or compress the video signal and reproduce the screen with less data, and it can be reproduced. It is possible to reproduce the screen even when searching with a small amount of data. The video signal is also input to the formatter 2 as normal reproduction data as it is, and is formatted by the formatter 2 together with the search data into a track pattern as shown in FIG. 2 to be recorded data. The recording data is input to the error correction encoder 3, modulated by the modulator 4, and recorded on the magnetic tape 6 by the recording head 5.

At the time of reproduction, the recording data is reproduced from the magnetic tape 6 by the reproducing head 7 and demodulated by the demodulator 8. The demodulated data is error-corrected by the error-correction decoder 9 and input to the deformatter 10. The deformatter 10 separates the normal reproduction data and the search data and outputs them separately. During normal playback, connect the contact piece to the terminal a side with the switch 12,
The normal reproduction data is output as a video output. Further, at the time of search, the contact piece is connected to the terminal b side by the switch 12 to expand the search data which is input to the search video decoder 11 and compressed, and is returned to the same format as the normal reproduction to obtain a video signal. Output.

Hereinafter, the time for recording one frame of video during normal reproduction will be referred to as one frame period, and the section on the magnetic tape in which one frame of video is recorded will be referred to as one frame section.

FIG. 2 is an example of a track pattern formed by the formatter 2. Areas 30, 31, 3
2, 33, 34, 35, 36, 37, 38 and 39 are search data areas, and are areas 20, 21, 22, 2
Reference numerals 3, 24, 25, 26, 27, 28 and 29 are normal reproduction data areas. The search data is in the search data areas 30, 31, 32, 33, 34, 35, 36, 3
7, 38 and 39, the normal reproduction data are 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, and one frame of data at time (n + 1) is recorded in the normal reproduction data area 22 at time (n + 2). 1 frame of data is recorded in the normal reproduction data area 23, 1 frame of data at time (n + 3) is recorded in the normal reproduction data area 24, and 1 frame of time (n + 4) is recorded. Data is recorded in the normal reproduction data area 25.

On the other hand, although the search data is recorded in the search data area, the tape speed during the search is higher than that during the normal reproduction. Therefore, for example, if the search speed is set to four times that during the normal reproduction, When searching, the magnetic tape is sent 4 times, so in one frame period, it is 4 times the normal playback
Play the frame section.

Therefore, the search data in the frame n is divided into four, and the search areas 31 and 3 in the four frame sections are divided.
Record at 2, 33 and 34. Then, in the next search area, search data for frame (n + 4) is 4
Search areas 35, 36, and 3 for four frame sections by dividing
Record at 7 and 38. Thereafter, recording is similarly performed.

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

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 on the screen is recorded in the other four frame sections. 1 in one frame period
It is possible to play back half the video of a frame.

As a head, as shown in FIG. 5, consider a head configuration in which the heads are opposed to each other by 180 degrees and the azimuth angles are different from each other. In this head configuration, when the cylinder makes one rotation when the tape running speed is 4 times the normal playback speed, the head path shown in FIG. 6 is taken. The shaded 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 in a certain portion of the track, either of the two heads can always reproduce this data. Since the head A and the head B complement each other to reproduce the data, the same data may be recorded during each scan. This is the number of tracks twice the search speed in the head configuration of FIG. 5, and 8 tracks at the quadruple speed. As described above, by recording the same data in the search area during the period in which the cylinder makes one revolution at the even speed, that is, during the 2n tracks at the n speed, this data can be reliably reproduced. This does not change with different head paths.

By recording with such a track pattern, the 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) is distributed over 8 (= 4 × 2) tracks.
5) is recorded. If the search is performed at a quadruple speed, the heads A and B reproduce this area once. With the data arrangement as described above, it is possible to reproduce the data A1, A2 and A3 by the head A and the data A4 and A5 by the head B during the head pass as shown in FIG.

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

If two heads separated by one track as shown in FIG. 7 and having different azimuths are provided at one location of the cylinder, the head path is as shown in FIG. 8 at the integer + 1/2 speed. become. At this time, by recording A, B, A, B, ... For each track in the search area, it is possible to reliably reproduce the data of A and B while the cylinder makes two revolutions.

Although the normal reproduction data and the search data are distinguished from each other in this embodiment, the normal reproduction data may be compressed as the search data, or the normal reproduction data may be used as it is. Data or completely different data. In addition, although an example has been described in which the normal reproduction data is recorded at the beginning of the track and then the search data is recorded, the search data may be recorded first. Further, although the search speed is quadrupled, a faster search may be used.

Although the search speed is set to 4 times in the present embodiment, the same effect can be obtained when the search speed is set to -4 times. When the track pattern is determined in this way, the track patterns for the forward search and the backward search are the same.

Further, in the present embodiment, the search speed is fixed to 4 times and the track pattern is determined. However, this may be formatted into a track pattern which enables a search at a plurality of search speeds. Further, although the head configuration has been described as 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 search data encoding means using the video signal input as search data and formatting means for rearranging the search data so as to record a plurality of identical data over n tracks, the image quality at the time of search is improved, It is possible to obtain a stable output, and a digital VTR
If it is used for, it will produce a great effect.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a recording / reproducing apparatus of 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 arrangement example of heads used in the recording / reproducing apparatus of the present invention.

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

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

FIG. 8 is a track pattern diagram recorded by the recording / reproducing apparatus in one 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 running 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]

 1 Search Data Encoder 2 Formatter 3 Error Correction Encoder 4 Modulator 5 Recording Head 6 Magnetic Tape 7 Playback Head 8 Demodulator 9 Error Correction Decoder 10 Deformatter 11 Search Data Decoder 12 Switch

Claims (4)

[Claims] 1. In a recording / reproducing apparatus for sequentially recording / reproducing tracks by a head mounted on a rotary cylinder, a track to be recorded is divided into an area for normal reproduction and an area for high-speed reproduction. Is recorded and the same data is recorded over n tracks in an area to be reproduced at high speed reproduction. 2. The speed during high speed reproduction is an even multiple speed, and the n track is twice as high as the speed during high speed reproduction.
The recording / reproducing apparatus described. 3. The speed during high speed reproduction is an odd multiple speed, and the n track is the same as the speed during high speed reproduction.
The recording / reproducing apparatus described. 4. A recording / reproducing apparatus for sequentially recording / reproducing tracks by a head attached to a rotary cylinder, and search data encoding means for encoding a video signal input as search data, and n tracks of the search data. Formatting means for arranging a plurality of the same data in a recordable manner, recording means for recording the data output from the formatting means on a recording medium, reproducing means for reproducing the recorded data from the recording medium, and the reproducing means. A recording / reproducing apparatus having a deformatter means for separating normal reproduction data and search data from the data reproduced by the above and individually outputting them.