KR19990001905A - Double speed playback apparatus and method in video disk system - Google Patents

Abstract

The present invention relates to a double speed playback device and method in a video disc system that reads data from a disk at high speed during MPEG playback, decodes MPEG, and then selects and displays frames at predetermined intervals according to the speed type. By rotating the disk at high speed to read the data, amplifying and waveform shaping the read data at high speed, and MPEG-decoding the waveform shaped data to form all the frames, and then selecting specific frames required at predetermined intervals according to the type of double speed. By constructing and displaying 30 frames in seconds, it is possible to perform natural high speed playback as if the screen is progressed at the correct double speed.

Description

Double speed playback apparatus and method in video disk system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to double speed playback in a disc type video playback device such as a video CD, digital versatile disc (DVD) system, and the like. The present invention relates to a double speed playback apparatus and method in a video disc system for performing high speed playback by selecting only a specific frame according to the type.

In general, in a digital video system, each frame of an image is sampled in units of pixels. Since image information is very large, an image compression (or encoding) technique is required for efficient transmission or storage.

It mainly uses a method of removing redundant information in the space and time domain.

The redundancy in the spatial domain is due to the small degree of change between adjacent pixels in one frame, and the redundancy in the time domain is due to the slight change in object movement between adjacent frames.

In particular, in MPEG, a sequence of a moving image is divided into a plurality of frames, that is, a GOP (Group Of Picture) composed of pictures, and encoding is performed.

There are three types of image types to be encoded: I (intra code), P (forward prediction code), and B (bidirectional prediction code).

The GOP is composed of an I picture which is an intra-frame coded picture, a P picture that is a coded picture between frames that are already coded and temporally processed in a previous frame, and a B picture that is a bidirectional predictive interpolation picture that is predicted in two frames before and after.

In other words, MPEG introduces a B picture featuring inter-frame predictive coding, inserts an I picture (in-frame) by intra-frame coding at an appropriate interval, while ensuring a sufficient compression rate, thereby overcoming image quality degradation due to error measurement.

Therefore, conventionally, when a high speed mode using only I pictures is determined by double-speed playback of a disc on which MPEG-coded data is recorded, when a B picture or P picture is encountered on a disc, track jumps to the position of the next I picture. In the low speed mode using the I and P pictures, only the I picture is read from the disc. When the B picture is encountered, the track jumps to the position of the next I or P picture.

For example, in the 3x playback mode, the B picture does not read out from the disc and only the I and P pictures are read out and displayed. In the 12x playback mode, only the B picture and the I picture are not read out. Read and display as shown.

However, the above-described double speed reproduction method requires moving the pickup continuously, but it is difficult to construct a 30-frame screen for one second at the normal pickup movement speed.

In other words, if only I pictures are displayed at the normal pick-up movement speed, there are not 30 I pictures in one second. In addition, even when I and P pictures are displayed, I and P pictures must be searched and read while moving between tracks, so that there are not 30 I or P pictures in one second.

Therefore, it is difficult to compose such a screen as if the movie is being rotated quickly, and a screen that is as if watching a slide appears.

In addition, although compressed data is recorded on the disk, the amount of data per fixed time is often inconsistent depending on the compression method. Therefore, if the location of data corresponding to the screen after a certain time is not constant, and you want to display the screen at a fixed speed such as 2 times or 3 times, you need to know the location of the data corresponding to the screen after a certain time first. Hard to find.

In addition, when making a disc, it must be made in consideration of this to enable high speed playback at a predetermined speed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to speed up data read speed and digital signal processor (DSP) speed from a disc during double speed playback, and then to configure the entire screen, Accordingly, the present invention provides a device and method for double speed playback in a video disc system which performs smooth high speed playback by selecting and displaying required frames at predetermined intervals.

Features of the double speed reproducing apparatus of the video disc system according to the present invention for achieving the above object are an optical pickup that reads data from the disc by controlling the rotation of the disc at a normal or high speed according to the type of double speed, and the optical DSP which amplifies and waveform-forms the signal read out from the pickup at normal or high speed according to the double speed type, and selects and outputs the signal according to the control signal And a control unit for controlling frame selection of the DSP and the MPEG decoder.

A characteristic of the double speed playback method in a video disc system according to the present invention is a high speed playback mode, which comprises a first step of reading data by rotating the disc at high speed, and amplifying and waveforming the data read out in the first step at high speed. And a third step of performing MPEG decoding on the waveform-shaped data in the second step and selecting and displaying a specific frame according to the type of the double speed.

1 is a view showing an example of a double speed playback process in a conventional video disc system

2 is a block diagram of a double speed playback device in a video disc system according to the present invention;

3 is a flowchart of a method of double speed playback in a video disc system according to the present invention.

4 is a diagram illustrating an example of a double speed playback process in a video disc system according to the present invention;

* Description of the symbols for the main parts of the drawings *

20 disc 21 optical pickup

22: DSP22-1: first digital processing unit

22-2: second digital processing unit 22-3, 24-3: multiplexer

23: Micom 24: MPEG decoder

24-1: decoding section 24-2: frame selection section

25 display unit 26 key input unit

27: servo control unit

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

Fig. 2 is a block diagram of a double speed playback apparatus in a video disk system according to the present invention, in which a compressed disk, in particular MPEG encoded data is recorded, controls the rotation of the disk according to a playback mode. An optical pickup 21 for reading data from the optical pickup 21, and a digital signal processor (DSP) 22 for amplifying and waveform-shaping the signal read out from the optical pickup 21 at a normal or high speed in accordance with a reproduction mode. The microcomputer 23 which controls the control of the DSP 22 and the data reading of the disk 20, and decoded the waveform-formed signal by the control of the microcomputer 23 according to the type of the speed The MPEG decoder 24 for selecting a specific frame, the display unit 25 for encoding and displaying the output signal of the MPEG decoder 24, the key input unit 26 for selecting a double speed playback mode, and the microcomputer 23 Optical peek by control And a servo controller 27 for controlling the tracking and focusing of the up 21.

The DSP 22 amplifies and waveforms the RF signal read out from the pickup 21 at a high speed by a first digital processor 22-1 for amplifying and waveform shaping the RF signal read out from the pickup 21 at a normal speed. The MPEG decoder 24 controls the processing result of the first digital processing unit 22-1 or the second digital processing unit 22-2 under the control of the shaping second digital processing unit 22-2 and the microcomputer 23. The multiplexer 22-3 outputs the selective selection.

The MPEG decoder 24 MPEG-decodes the output of the multiplexer 22-3 of the DSP 22 by the decoding unit 24-1 and the decoding unit 24- in accordance with the type of the double speed output from the microcomputer 23. A frame selector 24-2 for selectively outputting frames at a predetermined interval among the outputs of 1), and an output or frame selector 24-2 of the decoder 24-1 under the control of the microcomputer 23; The multiplexer 24-3 selects and outputs the output of the output to the display unit 25.

In this case, the frame selector 24-2 may be disposed in front of the display unit 25.

3 is a flowchart illustrating a method of double speed playback in a video disc system according to the present invention.

According to the present invention configured as described above, when the normal speed regeneration is selected through the key input unit 26 (step 301), the servo controller 27 rotates the disc 20 at the normal speed through the optical pickup 21, and the optical pickup ( 21 reads data from the disk 20 which rotates normally (step 302).

The signal read out from the optical pickup 21 is input to the DSP 22 in the form of RF.

At this time, the RF signal is amplified and waveform-shaped at the normal speed by the first digital processing unit 22-1 of the DSP 22 under the control of the microcomputer 23, and then the MPEG decoder 24 through the multiplexer 22-3. (Step 303).

The MPEG decoder 24 decodes the waveform-shaped data at the normal speed by the decoding unit 24-1 under the control of the microcomputer 23, and then outputs the data to the display unit 25 through the multiplexer 24-3. (Step 304).

The display unit 25 restores the original image using the I, P, and B pictures, and then displays the restored image (step 308).

On the other hand, if it is determined in step 301 that the high speed reproduction is not the normal speed reproduction, the servo controller 27 rotates the disc 20 at high speed through the optical pickup 21 and the optical pickup 21 at high speed according to the type of double speed. The rotating disk 20 is irradiated with a light beam, and the reflected beam is read and converted into an RF signal (step 305).

The RF signal read out at high speed is amplified and waveform-formed at high speed by the second digital processing unit 22-2 of the DSP 22 under the control of the microcomputer 23, and then, through the multiplexer 22-3, the MPEG decoder ( 24) (step 306).

The MPEG decoder 24 performs MPEG decoding on waveform-formed data at high speed by the decoding unit 24-1 under the control of the microcomputer 23, and then outputs the data to the frame selecting unit 24-2. 24-2 selects a specific frame according to the type of double speed output through the microcomputer 23 and outputs it to the multiplexer 24-3 (step 307).

That is, if the double speed type is 2x speed, as shown in FIG. 4, 30 frames are configured for 1 second by selecting one frame over one frame regardless of I, P, and B pictures.

If the speed is 3x, one frame is selected over two frames irrespective of the I, P, and B pictures, and if the 4x speed is selected, one frame is selected over three frames to form 30 frames in one second.

The multiplexer 24-3 outputs only the frame selected by the frame selector 24-2 to the display unit 25 under the control of the microcomputer 23, and the display unit 25 displays the selected frames by stitching them together. (Step 308).

As described above, according to the double speed playback apparatus and method of the video disc system according to the present invention, in the case of high speed playback, data are read out from the disc at high speed and DSP processed to configure all the frames, and then the intermediate frames are spaced at predetermined intervals according to the speed type. By discarding them and configuring 30 frames for one second with the remaining frames, smooth high speed playback can be performed at the correct double speed.

Also, depending on the compression method, 30 frames can be configured for 1 second at all times regardless of I, P, and B pictures, even if the amount of data is not constant. You do not need to know.

Claims (5)

A disk on which compressed data is recorded, An optical pickup for reading data from the disc by controlling the rotation of the disc at a normal or high speed according to the playback mode; A digital signal processor for amplifying and waveform shaping the signal read out from the optical pickup at a normal or high speed according to a reproduction mode and then selectively outputting the signal according to a control signal; An MPEG decoder which MPEG-decodes the waveform-formed signal at a normal or high speed in the digital signal processor and selects a specific frame according to a double speed type; And a controller for controlling frame selection of the digital signal processing unit and the MPEG decoder. The method of claim 1, wherein the frame selector And n-1 frames are selected one by one when the speed type output from the controller is n (n is a positive integer). In a playback method for playing back a disc on which data is recorded at a speed of n (n is a positive integer), A first step of reading data by rotating the disk at high speed in the high speed playback mode; A second step of amplifying and waveform-shaping the data read out in the first step at high speed; And a third step of performing MPEG decoding on the waveform-shaped data in the second step and then selecting and displaying a specific frame according to the type of a double speed. The method of claim 3, wherein the third step A method of double speed playback in a video disc system, characterized in that frames are selected one by one when the speed is n (n is a positive integer). The method of claim 3, wherein the third step A method of double speed playback in a video disc system, characterized in that the number of frames displayed on the screen per second during double speed playback is the same as the number of frames displayed on the screen per second during normal playback.