KR0124159B1 - Head assembly for digital vcr and trick mode playback method using the same - Google Patents

Abstract

Disclosed is a head assembly of a digital video cassette recorder and a special replaying method using the head assembly. The head assembly comprises a drum and the plural heads. The heads records the compressed image data into the tape, replays the recorded data, and replays the recorded data by horizontal scanning to the tape in the special replaying mode. Thereby, the image can be replayed perfectly by the scanning.

Description

Head of Digital V-Cal and Special Regeneration Method Using the Same

1 is a diagram showing a head direction in general playback of a VCR tape and a head direction in special playback.

2A and 2B show a traveling direction of a plurality of head assemblies and a plurality of head assemblies.

* Explanation of symbols for main parts of the drawings

1: Head direction in normal playback 2: Head direction in special playback

3: Progress direction of a plurality of head assemblies during special playback

4: Recording DCT Data 5: Mounted Drum Composed of Multiple Heads

6: head assembly 10: VCR tape

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital VCR, and more particularly, to a head assembly of a digital VCR capable of completely reconstructing an image in a special playback mode, and a special playback method using the same.

In general, in the case of a device that converts a video into a digital signal such as an HDTV and transmits the video signal, the bandwidth of the video signal is considerably wider than that of the audio signal, thereby increasing the amount of data to be processed relatively.

Therefore, a high rate data compression encoding method is used as a method for reducing the huge amount of data generated during transmission of a video signal.

As is well known, such data compression encoding methods include variable length coding, discrete cosine transform (DCT), subband coding, and the like. There are interframe differential coding and variable length coding using motion compensation.

Therefore, the digital VCR uses a method of recording and reproducing the compressed video data as described above. However, in special playback modes such as CUE and REVIEW, it is not possible to read the data compressed at a high rate in a sequential manner and display it on the screen in time, and when the high data rate is read like a conventional VCR, the screen configuration is perfectly It does not happen and the screen is broken.

The video data is recorded in the order of odd and even fields. In addition, as described above, for data compression to reduce the amount of data, DCT data is recorded in the first field, and a predetermined number of fields, starting from the next field, are used as a motion vector with the amount of difference in the image of the first field. In this way, DCT data is recorded for one field as described above, and only motion vectors referring to previous DCT data are recorded for the next predetermined number of fields. Therefore, when the recorded data is reproduced, the screen for the subsequent field can be reproduced by restoring the data of the field in which only the motion vector is recorded based on the DCT data.

Fig. 1 shows the head direction in the normal playback of data recorded on the VCR tape and the head direction in the special playback.

As shown in Fig. 1, when the tape advances in the special playback mode, the head's scanning angle for the track recorded on the tape does not match, so that the motion vector irrelevant to the initial DCT data is read, i.e., the actual motion. The DCT data used to obtain the vector cannot be read. As a result, the data of the field in which only the motion vector is recorded is not restored normally and the displayed screen is broken.

Accordingly, an object of the present invention is to provide a head assembly of a digital VCR and a special playback method using the same, which are designed to solve such a problem and to perfectly reproduce an image on a screen in a special playback mode.

According to an aspect of the present invention for achieving the above object, recording the compressed image data mounted on the tape and at a predetermined interval in the vertical direction on the outer peripheral surface of the drum on a tape, and recorded the recorded image data A head assembly of a digital VCR is provided, which is composed of a plurality of heads for reproducing, and for reproducing image data recorded on the tape by scanning the tape in a horizontal direction during special playback.

According to another aspect of the present invention for achieving the above object, in the special playback method of the digital VCR for reproducing the video signal recorded on the tape through a plurality of heads mounted at predetermined intervals in the vertical direction on the outer peripheral surface of the drum The special playback method using the head assembly according to claim 1, wherein the plurality of heads respectively play back the video signal while advancing in the horizontal direction of the tape so as to reproduce all the DCT data recorded on the tape. Is provided.

Hereinafter, the present invention will be described with reference to the drawings.

2A and 2B show the head assembly of a digital VCR composed of a plurality of heads according to the present invention and a heading direction of the head assembly of a digital VCR composed of a plurality of heads on a track of a VCR tape.

First, FIG. 2B shows a head assembly of a digital VCR composed of a plurality of heads and a drum on which the head assembly composed of the heads is mounted.

The head assembly 6 mounted on the drum 5 can extend the head by the number of DCT data recorded on the track, and can change the installation angle of the head to install and reproduce the image data recorded on the track of the tape. have.

Further, according to the present invention, at the time of special playback, the head assembly according to the present invention is used to advance each head in the horizontal direction, thereby reading only the compressed data after DCT conversion in the image field recorded on the track of the tape. The result is a perfect picture that is unbroken.

Also, as shown in FIG. 2A, the digital VCR head assembly 6 composed of a plurality of heads scans horizontally only the portions on which the compressed data after DCT conversion is recorded on the track of the VCR tape in the special playback. .

That is, as described above, when the head assembly 6 proceeds in the horizontal direction of the tape during the special playback, only the compressed DCT data recorded on the tape can be reproduced, so that a perfect image can be reproduced.

Therefore, in the present invention, the head assembly of the head assembly uses the head assembly during the special playback to read a perfect image that is not broken by reading and playing the compressed data after DCT conversion recorded on the track of the tape while the head assembly proceeds in the horizontal direction of the tape. There is an effect that can be obtained.

Claims (3)

Record the drum and the compressed image data mounted at a predetermined interval in the vertical direction on the outer circumferential surface of the drum on a tape, and reproduce the recorded image data, by scanning the tape in a horizontal direction during the special reproduction. Head assembly of a digital VCR consisting of a plurality of heads for playing back image data recorded on a tape. 2. The head assembly of a digital VCR according to claim 1, wherein the plurality of heads can adjust the number of the heads according to the compressed video data to be played on the tape. A special playback method of a digital VCR for reproducing a video signal recorded on a tape through a plurality of heads mounted at predetermined intervals in a vertical direction on an outer circumferential surface of a drum, wherein each of the plurality of heads is the tape during special playback. A special reproducing method using a head assembly, characterized by reproducing a video signal while advancing in a horizontal direction to reproduce all DCT data recorded on the tape.