KR0136022B1 - Slow reverse reproducing method of video compact disk - Google Patents

Abstract

The present invention is to provide a reverse slow playback method of a video compact disc in which all pictures are played at low speed in the reverse direction from the current playback position.

To this end, the present invention provides a video compact disc playback method for playing a video compact disc on which audio / video information is recorded by using the MPEG method, which is provided on a disc corresponding to an I picture of a video data stream in a normal forward playback mode. When the reverse slow playback mode is selected, the position data is stored in sequence, and based on the position data of the immediately preceding I picture of the currently displayed picture, the I picture on the disc is reproduced from the currently displayed picture to the currently displayed picture. And decoding the picture immediately before the picture being displayed and then displaying the last decoded picture.

Description

Reverse Slow Play Method of Video Compact Disc

1 is a main block diagram of a general video compact disc player implementing the method of the present invention;

2 is a detailed configuration diagram of a memory for explaining the operation relationship between the memory and the MPEG video decoder shown in FIG.

3 are diagrams showing the picture order encoded in MPEG video data, the picture order being displayed;

4A to 4G illustrate the order of pictures stored in the frame buffer and the display buffer of the memory shown in FIG. 3 in the reverse slow playback method according to the present invention.

Explanation of symbols on the main parts of the drawings

2 ---- disc, 4 ---- spindle motor,

6 ---- servo circuit part, 8 ---- first microcomputer,

10 ---- pickup, 12 ---- preamplifier,

14 ---- digital signal processor, 18 ---- CD-ROM decoder,

20 ---- MPEG video decoder, 22 ---- memory,

24 ---- digital / analog converter, 26 ---- RGB encoder,

222 ---- data storage, 224 ---- frame buffer,

226 ---- Display buffer section.

The present invention relates to a reverse slow playback method of a video compact disc, and more particularly, to a reverse slow playback method of a video compact disc for reproducing all pictures at a low speed in a reverse direction from a current playback position.

Recently, an MPEG information recording medium that records audio / video information using a Motion Picture Expert Group (MPEG) method such as a Video Compact Disc (VCD) has attracted attention as a next generation audio / video information recording medium. In the MPEG type information recording medium, video information and audio information are recorded in a compressed state based on a standard for moving picture processing proposed in the MPEG standard. Here, in the case of a video compact disc, the reproduction amount thereof is recorded for about 74 minutes on the information recording surface of the 12 cm compact disc.

In general, a video compact disc player for playing such a video compact disc can play not only a video compact disc (VCD) in which moving pictures and audio information are recorded, but also a compact disc (CD) in which only voice data is recorded. It is put into practical use as a composite product.

1 is a diagram showing the main block structure of a video compact disc player capable of selectively reproducing a compact disc (CD) and a video compact disc (VCD). As shown in the figure, a video compact disc player, like a video compact disc, includes an optical disc 2 on which audio / video information is recorded using an MPEG method, and a spindle motor for rotating the optical disc 2 at high speed. 4), pickup 10 for reading data recorded on the optical disc 2, drive of the spindle motor 4 and transfer of the optical pickup 10, and not shown installed in the optical pickup 10 A key having a plurality of control keys such as a servo circuit section 6 for controlling the output of the laser diode, a preamplification section 12 for amplifying the data read by the pickup 10, and a plurality of power on / off keys. A first microcomputer 8 which performs control operation of the entire system according to a control key input from an input unit (not shown), and a digital signal destination which processes the data amplified by the preamplifier 12 into a serial data stream. A CD-ROM decoder 18 for decoding data from the digital signal processor 14, extracting sector-by-sector, and separating and outputting MPEG data and control data from the CD-ROM decoder 18. MPEG video decoder 20 for decoding and outputting MPEG data according to audio and video synchronous clocks (90 kHz), and receiving control data from the CD-ROM decoder 18 and receiving the MPEG video decoder based on the control data. A second microcomputer 16 for outputting the decoding control signal of (20), a digital / analog converter 24 for converting the digital video data decoded by the MPEG audio / video decoder 20 into analog, and the analog to And an RGB encoder 26 for converting the converted video signal into a composite video signal having R, G, and B color signals and outputting the converted video signal. Here, in the present specification and drawings, only the video signal processing system of the video compact disc will be described and described only for the sake of simplicity and simplification of the drawings.

Next, the operation of the video compact disc player constructed as above will be described schematically. That is, when a commercial user first selects a predetermined song while the video compact disc is mounted on the disc tray or more, and then presses the play key of a key input unit (not shown), the first microcomputer 8 recognizes this and the servo circuit unit 6 recognizes this. The control signal is outputted to the control unit to control the driving of the spindle motor 4 and the transfer of the pickup 10, and also to output the control signal to the digital signal processor 14. Accordingly, the data of the position corresponding to the predetermined song on the disc 2 is read by the pickup 10 and input to the digital signal processor 14 via the preamplifier 12, which is the digital signal processor. In 14, the data input from the preamplifier 12 is signal processed into a serial data stream. Thereafter, the CD-ROM decoder 18 decodes the serial data stream transmitted from the signal processor 11, outputs control data to the second microcomputer 16, and outputs MPEG video data to the MPEG video decoder 20. Done. Subsequently, the MPEG video decoder 20 decodes the input MPEG video data according to the A / V synchronous clock (90 kHz) based on the control data input from the second microcomputer 16 and outputs the same. The video signal is converted into an analog composite video signal by the digital / analog converter 24 and the RGB encoder 26 and output. Here, a first-in first-out (FIFO) memory unit (not shown) is provided inside the MPEG video decoder 20, and the MPEG video data is sequentially stored in the memory unit of the FIFO system. Will be.

The MPEG video data recorded on the video compact disc is made of any one of an I picture (Intra coded picture), a P picture (Predictive-coded picture), and a B picture (Bidirectionally predictive-coded picture). In this case, the I picture is encoded by performing DCT processing without taking a difference, so that the image is reconstructed using only information of one picture itself. This encoding method generally decreases data compression efficiency, but if it is put everywhere, random access or high speed playback is performed. This becomes possible. The P picture is a predictive picture which is located earlier in time and compressed using motion compensation prediction in an I picture or a P picture as a reference picture that has already been decoded. In addition, the B picture is an I picture or a P picture as a reference picture decoded and positioned before in time, an I picture or a P picture as a reference picture decoded and positioned in time and decoded, and three types of interpolation images made in both directions thereof. Is a predictive image compressed using motion compensation prediction in.

Such a method of decoding and displaying such MPEG video data includes a forward playback mode for playback at a normal playback speed, a forward slow playback mode at a slightly slower speed than the forward playback mode, and a fast forward search for a screen in a high speed forward direction. There is a search mode and a reverse fast search mode for searching the screen in a fast reverse direction. Here, in the fast forward search mode and the reverse fast search mode, the fast search of the screen is performed by sequentially reproducing the first outgoing picture by jumping forward or backward by a predetermined interval (predetermined frame) corresponding to a predetermined picture.

However, conventionally, since the data sequence consisting of the I picture, the P picture, and the B picture of the video data stream input to the MPEG video decoder 20 does not match the displayed sequence, there is a problem that slow playback of MPEG video data cannot be performed in the reverse direction. there was.

Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide a reverse slow playback method of a video compact disc in which all pictures are played at low speed in the reverse direction from the current playback position.

According to the reverse slow playback method of a video compact disc according to the present invention to achieve the above object, in the playback method of a video compact disc for playing back a video compact disc recorded with audio / video information using the MPEG method, In the normal forward play mode, the position data on the disc corresponding to the I picture of the video data stream is stored in sequence, and when the reverse slow play mode is selected, the disc is based on the position data of the immediately preceding I picture of the picture currently being displayed. Playback from the I picture on the picture to the picture currently being displayed, decoding the picture immediately before the picture currently being displayed, and then displaying the last decoded picture.

Hereinafter, a reverse slow playback method of a video compact disc according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a detailed configuration diagram for explaining the operation of the memory 22 and MPEG video decoder 24 in which MPEG video data is temporarily stored in the general video compact disc player shown in FIG. As shown in the figure, the memory 22 stores the MPEG video data input in the frame unit from the CD-ROM decoder 18 to the FIFO type memory unit (not shown) of the MPEG video decoder 20. A data storage unit 222 for storing an address in a memory unit (not shown) of the FIFO method and three pieces of data for which MPEG video data is decoded in units of frames by the MPEG video decoder 20. And a display buffer 226 among the frame buffer unit 224 including the frame buffers 224A, 224B, and 224C and the frame data stored in the frame buffers 224A, 224B, and 224C. Here, the frame data stored in the display buffer 226 is output directly to the digital / analog converter 26 by the MPEG video decoder 24.

In the present invention, the absolute time (minutes and seconds) and the block number (sector number) of the video compact disc corresponding to the I picture of the video data stream reproduced so far are stored in the second microcomputer 16.

Next, a reverse slow playback method of a video compact disc according to the present invention will be described with reference to FIGS. 3 and 4. FIG.

3 is a diagram showing a picture order in which MPEG video data is encoded, and FIG. 3 is a diagram showing a picture order in which MPEG video data is displayed.

As shown in Figs. 3A and 3B, the reproduction order of pictures in the case where the current search position is 14I and the reverse search method of the video compact disc according to the present invention is applied will be described.

That is, first, the frame buffers 224A, 224B, and 224C and the display buffer 226 of the memory 22 shown in FIG. 2 are respectively shown in FIG. 4A as shown in FIG. 4A (10P, 14I, 13B). 14I is stored. In this state, when the reverse slow playback mode according to the present invention is selected, the second microcomputer 16 determines the absolute time (minutes and seconds) of the video compact disc with respect to the I picture (i.e., 7I) immediately before the 14I currently being displayed. And block number (sector number) are sent to the first microcomputer 8, and under the control of the first microcomputer 8, the pickup 14 is currently displayed from the I picture 7I on the disc 2 14I. Play until. Then, the second microcomputer 16 controls the MPEG video decoder 20 to display 13B, which is the picture displayed immediately before the picture 14I currently being displayed, as shown in FIG. 4B. 13B is outputted as a video signal output signal via the digital / analog converter 24 and the RGB encoder 26.

Subsequently, the second microcomputer 16 determines the absolute time (minutes and seconds) and the block number (sector number) of the video compact disc for the I picture (i.e., 7I) immediately before 13B currently being displayed. 8), under the control of the first microcomputer 8, the pickup 10 reproduces from the I picture 7I on the disc 2 to the picture 13B currently displayed. Thereafter, the second microcomputer 16 controls the MPEG video decoder 20 to display 12B, which is a picture displayed immediately before the picture 13B currently being displayed, as shown in FIG. 4C. 12B is outputted as a video signal output signal via the digital / analog converter 24 and the RGB encoder 26.

Next, the second microcomputer 16 displays the absolute time (minutes and seconds) and the block number (sector number) of the video compact disc for the I picture (i.e., 7I) immediately before the 12B currently being displayed. (8), the pickup 10 reproduces from the I picture 7I on the disc 2 to the picture 14I currently displayed under the control of the first microcomputer 8; Thereafter, the second microcomputer 16 controls the MPEG video decoder 20 to display 11B, which is a picture displayed immediately before the picture 12B currently being displayed, as shown in FIG. 4D. 11B is outputted as a video signal output signal through the digital / analog converter 24 and the RGB encoder 26. By the method similar to the above, as shown in FIG. 4 e-g, 10P, 9B, and 8B are displayed one by one.

As described above, the second microcomputer 16 converts the absolute time (minutes and seconds) and the block number (sector number) of the video compact disc to the first microcomputer 8 for the I picture immediately before the currently displayed picture. And the pickup 10 reproduces from the I picture on the disc 2 to the currently displayed picture under the control of the first microcomputer 8, and then the second microcomputer 16 performs the MPEG video decoder 20. ) Is output to the display buffer 226 immediately before the picture currently being displayed.

As described above, according to the present invention, when the reverse slow playback mode is selected and the reverse slow playback mode is selected, the picture currently being displayed is stored in the position data on the disc corresponding to the I picture of the video data stream played so far. On the basis of the positional data for the I picture immediately before, the pickup 10 plays back from the I picture on the disc to the currently displayed picture, and then controls the MPEG video decoder to immediately before the picture currently being displayed. By repeating the operation of outputting the displayed picture to the display buffer, MPEG video data can be played at a slow speed in the reverse direction.

Claims (2)

In the video compact disc playback method of playing a video compact disc having audio / video information recorded using the MPEG method, In the normal forward play mode, the position data on the disc corresponding to the I picture of the video data stream is stored in sequence, and when the reverse slow play mode is selected, the disc is based on the position data of the immediately preceding I picture of the picture currently being displayed. Video compact, playing from the I picture on the picture to the currently displayed picture, decoding the picture immediately before the picture currently being displayed, and then displaying the last decoded picture. Reverse slow playback of the disc. 2. The method of claim 1, wherein the position data is an absolute time and a block number (sector number) on the video compact disc for the I picture.