KR19990031649A - How to control tempo of video disc player - Google Patents

Abstract

The present invention relates to a tempo control method of a video disc player, and more particularly, to a method in which a user can adjust a tempo when playing a karaoke video recording.

The tempo control method includes a first step of controlling the rotation speed of a disc in accordance with a high speed or a low speed playback mode; A second step of decoding the data reproduced in the fast or slow playback mode according to the first step; A third step of temporarily storing the data decoded in the second step in a memory; And a fourth step of monitoring the data storage amount of the memory and controlling the data output of the memory according to the occurrence of overflow or underflow.

Description

Tempo control method of video disc player.

The present invention relates to a tempo control method of a video disc player, and more particularly, to a method in which a user can adjust a tempo when playing a karaoke video recording.

Video discs (hereinafter referred to as "video CDs") are recording media used in karaoke, multimedia personal computers, game consoles, and the like. The data recorded on the video disc includes various types of data, ranging from still images such as general characters and images to moving images. The recorded data are read by an optical pickup device and signal processed, and then displayed on a display. Is displayed.

On the other hand, a video player such as the karaoke, a multimedia personal computer, a game machine, and the like, and a decoder (for example, MPEG) which are compatible with the video player to decode data are distinguished from each other. In other words, the speed of reading data recorded on the video disk using the optical pickup device is different from that of the signal processing process of decoding and displaying the data read from the optical pickup device.

Therefore, signal processing is required to constantly control the data transmission rate between the separated player and decoder.

Conventionally, a simple example of controlling the data transmission rate at a constant speed, a player such as karaoke has a speed control function. Therefore, this function and SRAM of predetermined size are used to realize data transfer with a minimum buffer size.

However, a video player that plays a conventional video disc always reads data from the disc at a constant speed (about 1.5 Mbps), and processes the signal at a constant speed even if the read data is displayed on the screen using the SRAM of the predetermined size. Is doing.

Therefore, when users play video discs using karaoke, there is a problem that they cannot play the disc at the tempo they want to call.

This is because a conventional video player plays data from a video disk at a constant bit rate. In addition, when the bit rate of reading data from the disk is varied, an underflow or overflow occurs in the memory during decoding of the bit stream input to the decoder, thereby temporarily holding the image ( Underflow) or part of the image is broken (when an overflow occurs).

Accordingly, an object of the present invention is to provide a tempo control method of a video disc player which can vary the bit rate of reading data from the video disc.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing the configuration of a tempo control apparatus of a video disc player according to the present invention.

2 is an operation flowchart for a tempo control method of a video disc player according to the present invention;

(Explanation of symbols for the main parts of the drawing)

1: Video Disc 3: Pickup Device

5: Servo unit 7: Key matrix

9: display unit 11: microprocessor

13 CD signal processor 15 memory

17: MPEG decoder 19: digital video encoder

21: digital / video encoder 23: key control unit

25: high frequency amplifier

A tempo control method of a video disc player according to the present invention for achieving the above object comprises: a first step of controlling a rotational speed of a disc in accordance with a high speed or a low speed playback mode; A second step of decoding the data reproduced in the fast or slow playback mode according to the first step; A third step of temporarily storing the data decoded in the second step in a memory; And a fourth step of monitoring the data storage amount of the memory and controlling the data output of the memory according to the occurrence of overflow or underflow.

The tempo control method of a video disc player according to the present invention is characterized in that the speed of reading data from a video recording disc for karaoke can be varied according to user selection.

In addition, the tempo control method of a video disc player according to the present invention controls a decoder and a memory for storing the decoded data in order to suppress an underflow or overflow of a decoder generated when the speed of reading from a disc is changed. Characterized in that.

The tempo control method of a video disc player according to the present invention includes a device for reducing the original tone by key control to the final audio output stage in order to control the change of audio tone generated by varying the speed of reading from the disc. It is characterized by.

Hereinafter, a tempo control method of a video disc player according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing the configuration of a tempo control apparatus of a video disc player according to the present invention.

In the configuration, a video disk 1 storing various types of data, a pickup device 3 for reading data from the disk 1, and a signal amplifying a signal read out from the pickup device 3 And a high frequency amplifier 25 for outputting digitization, focusing error, and tracking error signals.

And a servo unit including focus servo control for maintaining a constant distance between the lens of the pickup device 3 and a disk signal surface, a tracking servo for following the track pit, a slide servo for moving the pickup around and around the pickup, and the like. (5) is included.

In addition, the CD signal processor 13 inputs the signal amplified by the high frequency amplifier 25, demodulates the modulated signal, and performs signal processing such as error correction. The CD signal processing unit 13 and the servo unit 5 are operated under the control of the microprocessor 11, and the microprocessor 11 inputs a key signal input by the user from the key matrix 7, Also, predetermined OSD information is displayed on the display unit 9.

MPEG decoder 17 for decoding the bit stream output from the CD signal processor 13 and external memory 15 for temporarily storing predetermined data in the process of decoding the bit stream input to the decoder 17. And an encoder 19 for converting the video signal output from the decoder 17 to be output to a television receiver, and an audio digital / analog for converting the video signal output from the decoder 17 into an analog signal for outputting the audio signal. And a transducer 21.

The audio signal output from the MPEG decoder 17 is output through the key control unit 23 included therein. The key control unit 23 is configured to return the output audio tone to the original tone.

Next, an operation process for tempo control of the video disc according to the above configuration will be described in detail.

2 is an operation flowchart for a tempo control method of a video disc player according to the present invention.

A video player called karaoke is a device that plays video recordings. Therefore, when playing a video disc using this karaoke, users must play the disc at the tempo they want to sing.

By this need, the user selects whether to play the video disc 1 currently mounted on the turntable in the normal playback mode or in the variable speed playback mode according to the high speed and the low speed. This selection is made by selecting the normal playback key or the shift playback key included in the key matrix 7. Therefore, when the user selects the normal playback key included in the key matrix 7, the microprocessor 11 controls to read data from the video disc 1 at a constant speed and perform signal processing by the same method as the conventional method. do.

However, when the user selects the shift playback key in the key matrix 7 (step 101), the microprocessor 11 recognizes that the shift playback mode of the disk 1 is selected and the CD signal processor 13 and the servo unit ( 5), the speed (bit rate) of reading data from the disc 1 is adjusted.

That is, when the shift playback mode is selected in step 101, the microprocessor 11 determines whether the user has selected high speed playback or low speed playback (step 103).

When the low speed regeneration is selected in step 103, the microprocessor 11 outputs a control signal according to the low speed regeneration to the servo unit 5. At this time, the servo unit 5 outputs a signal according to the low speed control to the motor controlling the rotational speed of the disk 1, so that the disk 1 is rotated at a low speed state (step 115).

Therefore, the speed of reading the data recorded on the disc 1 from the pickup device 3 will be slowed down, and the data read slower than the normal speed will be used for reproduction of the CD by the high frequency amplifier 25 and the CD signal processor 13. Necessary signal processing is performed and output.

Next, the bit stream output from the CD signal processing unit 13 performs a decoding process. The bit stream processed by the CD signal processing unit 13 is stored in the memory 15, and then the MPEG decoder 17 When the amount of data suitable for decoding (usually a picture amount) is reached, the decoding process is performed in the MPEG decoder 17.

However, the memory 15 is a memory of a limited size configured to control the decoding amount of the MPEG decoder 17 at the speed according to the normal reproduction. Therefore, there is a fear that underflow occurs in the memory 15 in the reproducing mode according to the low speed reproducing.

Therefore, the microprocessor 11 constantly monitors the amount of data stored in the memory 15, and if a risk of underflow is detected (step 117), the microprocessor 11 repeatedly repeats the currently decoded screen. A control signal for outputting is output (step 119).

The data subsequently read out from the pickup device 3 is stored in the memory 15 after predetermined signal processing through the high frequency amplification unit 25 and the CD signal processing unit 13, and thus the memory 15 If a predetermined amount of data is stored in the MPEC decoder 17, the decoding process is performed again. That is, when there is a risk of underflow, the bit stream for composing the new screen is decoded by one field delay.

The video signal decoded by the decoder 17 is output after being converted into a signal such that the digital video encoder 19 can display on a television monitor.

On the other hand, since the speed of reproducing data from the disc 1 becomes slow in accordance with the low speed reproducing mode in step 115, the audio signal output tone after being decoded by the decoder 17 becomes lower than the reference tone.

Therefore, the microprocessor 11 monitors the audio tone after decoding, and when the audio tone is lower than the normal reproduction (step 121), the audio tone according to the normal reproduction is supplied to the key control unit 23 included in the MPEG decoder 17. In step 123, a control signal for converting the signal is output.

By the above process, the audio signal output from the MPEG 17 has an audio signal of normal tone, and the output audio signal is output in synchronization with the video signal output from the digital video encoder 19.

By the above process, the data recorded on the disc 1 can be reproduced at a slower speed than the normal playback speed, and the karaoke disc is reproduced at the slow tempo required by the user.

Next, when the user selects the high speed reproduction of the disc 1 in step 103, the microprocessor 11 outputs a control signal according to the high speed reproduction to the servo unit 5 and the CD signal processing unit 13 ( Step 105).

By performing in the step 105, the servo unit 5 rotates the disk 1 at a faster speed than in normal playback. Then, the speed at which data is read from the disc 1 by the pickup device 3 becomes faster than during normal playback, and the data at this higher speed is transmitted through the high frequency amplifier 25 and the CD signal processor 13. It is transmitted to the MPEG decoder 17.

The MPEG decoder 17 decodes the input data in a predetermined unit. In this case, the decoding speed of the decoder 17 is a speed at which data read from the disc 1 is input into the memory 15 after CD signal processing. Since it is slower, the memory 15 is likely to overflow.

Therefore, the microprocessor 11 constantly monitors the amount of data stored in the memory 15, and when there is a risk of overflow (step 107), I-picture and P-picture read from the disk 1 In step 109, a control signal for decoding only the remaining data except for the B-picture among the B-picture data is output. That is, in step 109, the B-picture is skipped.

When data can be stored in the memory 15 again, control is performed to resume data storage.

In this way, the video data decoded and output by the decoder 17 is input to the digital video encoder 19, converted into a signal that can be displayed on a television monitor, and output.

In addition, the audio data decoded and output by the decoder 17 is converted into an analog signal by the audio / digital converter 21 for audio and output in synchronization with the video signal output by the digital video encoder 19. However, at this time, the data immediately after the decoding in the decoder 17 is output in a tone higher than the reference audio tone by accelerating the reproduction speed.

Therefore, the microprocessor 11 monitors the audio signal immediately after the decoding is performed in the decoder 17, and when the audio signal tone is higher than in normal reproduction (step 111), the key control unit embedded in the decoder 17 itself. (23), the control is performed so as to be the reference tone (step 113).

The data recorded on the disc 1 by the above process is reproduced at the high speed required by the user, which means that the image disc is reproduced at a high tempo.

As described above, the tempo control method of a video disc according to the present invention, when the user controls the playback tempo of the disc at a low speed during the playback operation of the video disc in a player such as karaoke, underflow of the external memory of the decoder occurs By suppressing this, there is an effect that can prevent the instantaneous holding phenomenon of the output image by the underflow.

In addition, the tempo control method of the video disc according to the present invention, when the user controls the playback tempo of the disc at high speed during the playback operation of the video disc in a player such as karaoke, by suppressing the occurrence of overflow of the external memory of the decoder Therefore, there is an effect that can prevent the output image is partially broken due to overflow.

In addition, the tempo control method of the video disk according to the present invention, by controlling the final output of the audio signal is high or low by the high speed or low speed playback of the disc to the effect that allows the viewer to listen to the sound quality There is.

Claims (3)

A first step of controlling the rotational speed of the disc according to the high speed or low speed playback mode; A second step of decoding the data reproduced in the fast or slow playback mode according to the first step; A third step of temporarily storing the data decoded in the second step in a memory; And a fourth step of monitoring the amount of data stored in the memory and controlling the data output of the memory according to the occurrence of overflow or underflow. The method of claim 1, And controlling the audio signal decoded in the second step to a reference level. The method according to claim 1 or 2, The data output control of the memory of the fourth step includes skipping a part of data to be reproduced when a memory overflow occurs, and repeatedly outputting one screen output when an underflow of the memory occurs.