KR100259141B1 - Method for controlling reproducing velocity on the vdp - Google Patents

Abstract

PURPOSE: A method for reducing a playing speed in a video compact disk player is provided to combine a pick-up location control function of a compact disk drive with a frame maintenance/ignorance function of an MPEG(Moving Picture Experts Group) decoder. Therefore, it is possible to appreciate videos under a slow motion or a stop state. CONSTITUTION: A host CPU(10) confirms whether an N times slow key is inputted. If so, the host CPU(10) transmits a slow motion command to an MPEG(Moving Picture Experts Group) decoder(20). The MPEG decoder(20) outputs one frame, and confirms whether the frame is outputted as much as an N frequency necessary for a user. If not, the host CPU(10) repeats previous steps. If the frame is outputted as much as the N frequency, a transmission signal is transmitted from the MPEG decoder(20) to the host CPU(10). The next frame address movement is performed to output the next screen output. A ready completion interrupt for the next screen output is generated from the MPEG decoder(20) to the host CPU(10). The host CPU(10) confirms whether a slow key is inputted after a temporal pause release. If not, the host CPU(10) repeats the previous steps. If the slow key is inputted, the host CPU(10) completely releases a slow motion. The host CPU(10) performs a sequential operation.

Description

How to slow down the playback speed on video compact disc players

1 is a video compact disc player block diagram for applying the present invention.

2 is a signal flow diagram for slow playback in a video compact disc player of the present invention.

3 is a flowchart of slow playback in the video compact disc player of the present invention.

* Explanation of symbols for main parts of the drawings

10: host central processing unit 11: P-ROM

12: D-RAM 20: MPEG decoder

21: microcode 22: RAM

30: Compact Disc Kit 31: Front Panel / Remote Control

32: Compact Disc Kit Central Processing Unit

33: compact disc mechanism and pick-up

40: NTSC / PAL (US TV system / color TV system) encoder

50: audio digital signal processor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video compact disc player, and more particularly, to a method of slowing down a playback speed in a video compact disc player, which allows a user to slowly rotate a screen to watch or stop motion while watching a video compact disc.

A typical video player can speed up, slow down, or freeze the playback speed by adjusting the rotational speed of the motor, but the video compact disc player is fixed to the rotation and access speed specifications of the compact disc driver, and the MPEG decoder Since it is fixed to operate according to the access speed, it is not possible to change the playback speed by adjusting the rotation speed of the motor. In addition, 24 or 30 frames per second must be scattered through the decoder to output the video. Since there was not enough data to be played, the video could not be played back, so the user could not see the scene that he wanted to see in detail or slow down in slow motion.

Therefore, the present invention is characterized by enabling the slow motion and motion stop function by combining the pick-up position control of the compact disc driver, which accesses the data of a predetermined position of the compact disc, and the functions of the MPEG decoder.

That is, the host central processing unit is connected to the MPEG decoder and the compact disk kit to command and control various operations; An MPEG decoder that receives and decodes data encoded according to the MPEG standard of the compact disc kit; A compact disc kit central processing unit for controlling the compact disc; It consists of a compact disc kit that includes a mechanism and an input unit for playing the compact disc, and when the slow key of the compact disc kit is input, the MPEG decoder receives a command from the HST central processor and reduces the rate of one frame. Output as many times as possible to enable slow motion and motion stop.

Hereinafter, a configuration for applying the present invention will be described with reference to the accompanying drawings.

As shown in Fig. 1, the MPP decoder controls playback, operation stop, slow operation, and interrupt, and recognizes the user's key operation or the status of the compact disc kit and commands the compact disc kit to play, stop, or stop the operation. A host central processing unit 10; An MPEG decoder 20 for receiving and decoding data encoded in the MPEG standard of the compact disk kit under the control of the host central processing unit 10; A compact disc kit 30 such as a compact disc playback system; An NTSC / PAL encoder 40 for outputting video in a “NTSC” or “PAL” mode, which is a color TV system designated by the US TV Method Committee in accordance with the TV video output standard; Comprised of an audio digital signal processor (hereinafter referred to as an audio DSP) 50 for converting the MPEG decompressed digital audio signal into an analog signal, the compact disc kit 30 is provided with a keyboard or a remote controller. A front panel / remote control 31 which receives a user input from; A compact disc kit central processor 32 for controlling all parts of the compact disc kit under the control of the host central processing unit 10; Programmable ROM, which consists of a compact disk mechanism and pick-up 33, a device for mechanically driving the compact disk and reading out the compact disk data using a laser, and defines a series of operations of the host central processing unit 10. A P-rom 11 storing software; The D-RAM 12, which is a RAM for executing the program of the host CPU 10, is connected to the host CPU 10, and the microcode, which is a ROM, in which an algorithm for operating the MPEG decoder 20 is stored. 21); The RAM 22 for decompressing the MPEG and operating in accordance with the microcode 21 is connected to the MPEG decoder 20.

A method of slowing down the playback speed of the video compact disc player configured as described above is as follows.

As shown in FIG. 2, when the user presses a slow key on the front of the compact disk kit 30 while watching a video compact disk, the host central processing unit 10 recognizes this and sends a slow motion command to the MPEG decoder 20. The MPEG decoder displays only one picture for N frame times according to the user's desired deceleration magnification. After sprinkling one screen on N screens, the end signal is notified to the host CPU 10 and the next screen is played. In order to inform the compact disc kit 30 to calculate an absolute pause address and move it backwards, the MPEG decoder 20 generates a next display ready interrupt, which is information that the next frame can be displayed. The host central processing unit 10 receives the pause release signal from the host central processing unit 10, When the stream after the displayed picture is inputted to the disk kit 30 and is normally played back, the operation after pressing the slow key is repeated to keep the screen running slowly. Press again to release it completely.

The reproduction speed reduction ratio of the operation will be described in more detail as follows.

Since the movie consists of 24 frames in one second and the TV consists of 30 frames, if you press the 2x slow key during auditing, 24 frames are continuously input from the frame of the screen at the time the key is pressed to the MPEG decoder 20. However, it stores only the first 1 frame, discards the remaining frame data, and consists of 24 frames per second, so twice the slow key was pressed for 1/24 seconds per frame. By spraying only the frame twice, the magnification increases to a certain degree, and almost stops. Therefore, the same algorithm as described above enables the freeze.

The skew time will be described in more detail below.

When the compact disc kit 30 operates such as stopping motion or slow motion, a very accurate time calculation is required. When outputting only audio, if the audio is only connected when it is played again after stopping, It is hard to know, but in the case of an image, the connection operation is not smooth when it is cut off in the middle, and this should be considered in the system. The above disconnection is a structural problem of the compact disc kit 30 and communication with the host central processing unit 10. In order to play the next scene after a stop due to a time delay, the pick-up must be shifted and read before the paused time. If this time is sent too far, it takes too long to meet the video to be played. It's time consuming and if it's too short, Since the data comes out late or malfunctions due to communication time or the video data to be played back is not connected, the skew time is corrected. This value depends on the configured chip performance. The set is 15/75 seconds and the Sony chip set is 60/75 seconds.

FIG. 3 is a flowchart illustrating a method of reducing a playback speed in a video compact disc player operating as described above.

A first step S1 of checking whether N times slow keys are input; A second step (S2) of performing a slow motion command from the host CPU 10 to the MPEG decoder 20 when the slow key is input in the first step; A third step (S3) of repeating the present step if the N-pack decoder outputs one frame and checks whether the frame has been output N times by the desired magnification and does not output N times; A fourth step (S4) of transmitting the temporary transmission end signal from the MPEG decoder 20 to the host CPU 10 when outputting N times in the third step; A fifth step S5 of moving back to the next frame address for the next screen output; A sixth step S6 of generating an interrupt for preparing the next screen output from the MPEG decoder 20 to the host CPU 10; A seventh step (S7) of checking whether the slow key is input again after the release of the pause; An eighth step (S8) of repeatedly performing the second, third, fourth, fifth, sixth and seventh steps when the slow key is not input again in the seventh step; When the slow key is input again in the seventh step, the sequential operation is performed in a ninth step S9 of releasing the slow motion completely.

As described in detail above, the present invention repeatedly sprinkles one frame by combining pick-up position control of the compact disc driver and frame keeping and ignoring functions of the MPEG decoder in a video compact disc player, and the next screen is repeated in the same manner. Thus, there is a feature that can enjoy the image in slow motion or still state.

Claims (3)

A video compact disc player, comprising: a first step (S1) of checking whether an N times slow key is input; A second step (S2) of performing a slow motion command from the host CPU 10 to the MPEG decoder when the slow key is input in the first step; A third step (S3) of outputting one frame from the MPEG decoder and confirming whether the frame has been output N times by a desired magnification, or repeating the present step if the output is not performed N times; A fourth step (S4) of transmitting the temporary transmission end signal from the MPEG decoder to the host central processing unit when outputting N times in the third step; A fifth step S5 of moving back to the next frame address for the next screen output; A sixth step (S6) of generating a next screen output ready interrupt from the MPEG decoder to the host CPU; A seventh step (S7) of checking whether the slow key is input again after the release of the pause; An eighth step (S8) of repeatedly performing the second, third, fourth, fifth, sixth and seventh steps when the slow key is not input again in the seventh step; And a ninth step (S9) of releasing the slow motion completely when the slow key is input again in the seventh step. The method of claim 1, wherein in the first step, the user decreases the playback speed of the video compact player by increasing the value of the deceleration magnification N desired by the user by a predetermined size or more to display the same screen for a predetermined time and to pause the screen. Way. 2. The method of claim 1, wherein moving back to the next frame address for the next screen output in the fifth step defines how far behind the pick-up, which is calculated very precisely as an experimental value. A method of slowing down the playback speed of a video compact disc player, by subtracting a constant value from the current time to increase the accuracy of the back-up position and smooth the connection.