KR0135790B1 - Restoring method of digital video tape recorder in trick playing - Google Patents

Abstract

The present invention relates to a method of decoding a signal in performing a trick play of a digital video tape recorder. The present invention relates to a trick data recorded from a tape, and forms a DCT block using signals of one DC component and a plurality of AC components, and the IDCT block. A signal recovery method of a digital video tape recorder for restoring a signal of a trick data recorded by converting the data into a data, the method comprising: dividing the converted IDCT block into a first region, a second region, a third region, and a fourth region, and In order to expand and reconstruct each divided region into four independent IDCT blocks, data of each region is moved to reference data of an independent IDCT block, and each of the shifted reference data is assigned to each IDCT block to be reconstructed. Copy the same data to form an independent IDCT block, and restore the signal of the reconstructed IDCT block. It characterized in that it comprises the method.

Therefore, the present invention reads one data at the time of performing trick play, so that four areas can be reproduced, thereby providing an effective play in terms of four times memory and speed in comparison with the conventional decoding method.

Description

Signal Restoration Method of Digital Video Tape Recorder during Trick Play

1 is a flowchart for explaining a decoding method when performing trick play according to the present invention.

2A is a diagram for showing the situation where the head reads the recorded data from the tape.

FIG. 2B is a diagram showing the data read in FIG. 2A as a DCT block composed of one DC component and two AC components.

FIG. 2C is a diagram showing the result of converting the DCT block of FIG. 2B into an IDCT block.

FIG. 2D is a diagram showing the division of an 8 * 8 IDCT block into four 4 * 4 IDCT blocks.

FIG. 2E is a diagram showing the step of copying the 4 * 4 blocks moved to the upper left of each 8 * 8 block.

FIG. 2F is a diagram showing the division of one 8 * 8 IDCT block into four 4 * 4 IDCT blocks and copying each of them.

The present invention relates to trick play of a digital video tape recorder, and more particularly, to a method of decoding a signal in performing a trick play of a digital video tape recorder.

In general, decoding in the search mode that performs trick play of a digital video tape recorder does not require a resolution of image quality equivalent to that required by normal play. In other words, only the outline of the screen needs to be recognized. On the other hand, when performing trick play, more attention is paid to the play speed than the image quality.

Decoding is performed by displaying the data read by the head as a color signal at the position of the screen when performing normal play or performing trick play. At this time, when performing the trick play, the perfect picture is not decoded as described above. However, if a large portion of the screen can be decoded and displayed with a small number of bits, the play speed will be increased. Will be done.

Therefore, an object of the present invention is to devise to satisfy the requirements as described above, so that four regions can be reproduced by reading one data when performing signal decoding.

The method of the present invention for achieving the above object,

In the signal recovery method of the digital video tape recorder for reading the recorded trick data from the tape and constructing a DCT block with a signal of one DC component and a plurality of AC components and converting it into an IDCT block to restore the recorded trick data signal. In

Dividing the converted IDCT block into a first region, a second region, a third region, and a fourth region,

In order to expand and reconstruct each divided region into four independent IDCT blocks, data of each region is moved to reference data of independent IDCT blocks.

Each of the moved reference data is copied to the same data in each IDCT block to be reconstructed to form an independent IDCT block,

And reconstructing the signal of the reconstructed IDCT block.

Hereinafter, with reference to the accompanying drawings will be described the present invention in more detail.

1 is a flowchart for explaining a decoding method when performing trick play according to the present invention. In FIG. 1, step 100 is reading the recorded data from the tape. This will be described with reference to the drawings.

2A is a diagram for showing the situation where the head reads the recorded data from the tape. Referring to Fig. 2A, the head track at 5 times speed is shown and the part to be read is shown.

Continuing with FIG. 1, step 110 is a step of determining whether the data read in step 100 is trick data. If the data determined in step 110 is not the trick data, it is ignored. Step 120 is to configure the data DC component and AC component in the fixed field. In step 130, data of the DC component and the AC component of step 120 are configured as a discrete cosine tranformation (DCT) block.

This will be described with reference to the drawings.

FIG. 2B is a diagram showing the data read in FIG. 2A as a DCT block comprising one DC component and two AC components.

In FIG. 1, step 140 is a step of configuring the DCT block configured in step 130 as an Inverse Discrete Cosine Tranformation (IDCT) block in 8 * 8 blocks. This will be described with reference to the drawings.

FIG. 2C is a diagram showing the result of converting the DCT block of FIG. 2B into an IDCT block. 2C, it is composed of one DC component and 63 AC components.

In FIG. 1, step 150 is to divide the IDCT result of step 140 into four 4 * 4 blocks. This will be described with reference to the drawings.

FIG. 2D is a diagram showing the division of an 8 * 8 IDCT block into four 4 * 4 IDCT blocks. In FIG. 2D, the 4 * 4 block 12 at the top left of the 8 * 8 block 10 is moved to the 4 * 4 block 16 at the top left of the 8 * 8 block 14, and 8 * 8. The 4 * 4 block 18 at the top right of the block 10 is moved to the 4 * 4 block 22 at the top left of the 8 * 8 block 20, and 4 at the bottom left of the 8 * 8 block 10. * 4 block 24 moves to 4 * 4 block 28 at the upper left of 8 * 8 block 26, and 4 * 4 block 30 at the lower right of 8 * 8 block 10 is 8 *. The eighth block 32 is moved to the 4 * 4 block 34 at the upper left.

In FIG. 1, step 160 is the upper left 4 * 4 blocks 16, 22, 28 and 34 in each of the four 8 * 8 blocks 14, 20, 26 and 32 shown in FIG. Step to copy it. This will be described with reference to the drawings.

FIG. 2E is a diagram showing the step of copying the 4 * 4 blocks moved to the upper left of each 8 * 8 block. This will be described in the following drawings as a whole.

FIG. 2F shows one 8 * 8 IDCT block divided into four 4 * 4 IDCT blocks and duplicates them. In FIG. 2F, 8 * 8 IDCT blocks are copied into 16 * 16 IDCT blocks, respectively. This will reduce the quality of the screen, but can be four times as effective in the signal recovery.

The present invention constructed as described above can read four pieces of data when performing trick play, and thus four areas can be reproduced, thus providing four times as much memory and speed as compared to the conventional decoding method.

Claims (3)

A method of restoring a digital video tape recorder for recovering the recorded trick data signal by constructing a DCT block using a signal of one DC component and a plurality of AC components, and converting the recorded trick data from the tape. In Dividing the converted IDCT block into a first region, a second region, a third region, and a fourth region, In order to reconstruct and expand each divided region into four independent IDCT blocks, data of each region is moved to reference data of independent IDCT blocks. Each of the moved reference data is copied to the same data in each IDCT block to be reconstructed to form an independent IDCT block, And restoring a signal of the reconstructed IDCT block. In the signal recovery method of the digital video tape recorder for reading the recorded trick data from the tape and constructing a DCT block with a signal of one DC component and a plurality of AC components and converting it into an IDCT block to restore the recorded trick data signal. In Splitting the converted 8 * 8 IDCT blocks into 4 * 4 first, second, third and fourth regions, respectively, In order to expand and reconstruct each divided region into four independent 8 * 8 IDCT blocks, data of each region is moved to 4 * 4 reference data of independent 8 * 8 IDCT blocks. In each 8 * 8 IDCT block to be reconstructed, each of the 4 * 4 reference data that is reconstructed is copied to the same data to form an independent 8 * 8 IDCT block, And restoring a signal of the reconstructed 8 * 8 IDCT block. The method according to claim 2, wherein in each 8 * 8 IDCT block to be reconstructed, the same data is copied to the same data to form an independent 8 * 8 IDCT block. Copy to data is equally applied to each of the four first, second, third and fourth quadrants divided by 4 * 4 reference data centered on the center of the newly constructed 8 * 8 IDCT block. A method for restoring a signal of a digital video data recorder, characterized in that it is copied.