KR100190605B1 - Digital satellite video receiver - Google Patents

Abstract

The present invention relates to a digital satellite video receiver having a slow playback function having practical use and a cost-saving effect by allowing a particular screen to be played slowly according to a user's request while reducing the memory size. The present invention relates to a digital satellite receiver according to the present invention. The video receiver receives a high frequency signal and QPSK demodulates the signal, converts and converts the error into a digital signal, a demultiplexer which separates the digital signal output from the channel into a video signal and an audio signal, and controls the controller. A video / audio decoding unit for decoding a digital video signal and an audio signal of I, P, and B images inputted from the multiplexing unit, or decoding a video signal of I and P images stored in a memory unit; Under the control of the controller is input from the demultiplexer through the video / audio decoding unit A memory unit for storing I and P video signals of the digital video signal, a video encoding unit encoding the decoded digital video signal output from the video / audio decoding unit according to a TV broadcasting method, and the video / audio decoding unit The audio DAC unit converts the decoded audio signal input from the analog signal into an analog signal, and the video / audio decoding unit decodes the data stored in the memory unit and outputs the data when the slow playback is required. And a control unit for outputting a control signal to decode the video signal.

Description

Digital Satellite Video Receiver with Slow Playback

1 is a block diagram showing a schematic configuration of a digital satellite broadcast receiver.

2 is a block diagram showing the structure of a video signal compressed by the MPEG method.

3 is a flowchart showing the operation during slow playback according to the present invention.

* Explanation of symbols for main parts of the drawings

11 channel portion 12 demultiplexing portion

13 video / audio encoding unit 14 memory unit (DRAM)

15: video encoding unit 16: audio DAC

17 control unit (Micom)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital satellite video receiver (DSVR). The present invention relates to a digital satellite broadcasting receiver having a slow playback function capable of reproducing a digital video input signal compressed by an MPEG method at a slow speed according to a viewer's request. It is about.

In general, the satellite video signal is transmitted as a compressed signal according to the Moving Picture Experts Group (MPEG), an international standard for moving picture compression, so that a large amount of video information can be transmitted in a short time. In order to view a video, a digital satellite video receiver which decodes the video compressed by the MPEG method and converts the video into a TV broadcast signal must be provided.

The digital video broadcasting receiver converts the received high frequency input signal into a QPSK demodulation, a digital signal, and corrects an error generated during transmission, and then divides the digital signal into a video signal and an audio signal. Then, the MPEG decoder reads and decodes the digital audio signal and the digital signal, respectively, to decompress the compressed state. Then, the decoded video signal and the audio signal are input to the video encoding unit and the audio DAC, respectively, and converted into a signal of the same type as that of the TV broadcasting system (e.g., NTSC system, PAL system). It is applied to the video receiving terminal.

However, when a general viewer wants to view a specific screen slowly and sees it in detail, the conventional satellite broadcasting receiver stores all the separated video signals in a storage device, and then slows down the decoding process of the stored data so that they can be played at a slow speed. .

Therefore, conventionally, in order to slowly reproduce a specific screen, for example, 16 Mbytes of memory is required to store a screen for one second, which is inefficient in terms of cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a digital satellite image receiver having a slow playback function capable of playing a specific screen slowly according to a user's request while reducing the memory size.

As a technical means for achieving the above object, the present invention provides a digital satellite image receiver,

A channel section for receiving high frequency signals, QPSK demodulation, converting them into digital signals, and correcting errors;

A demultiplexer which separates the digital signal output from the channel unit into a video signal and an audio signal;

Video / audio decoding digital video signals and audio signals of I, P, and B images input from the multiplexing unit, or decoding I and P images stored in a memory unit under control of the controller. A decoding unit,

A memory unit for storing the I and P video signals of the digital video signal inputted from the demultiplexing unit through the video / audio decoding unit under control of the controller;

A video encoding unit encoding the decoded digital video signal output from the video / audio decoding unit according to a TV broadcasting method;

An audio DAC unit for converting the decoded audio signal input from the video / audio decoding unit into an analog signal;

And a control unit for outputting a control signal to decode the data stored in the memory unit when the slow playback request is performed, and to decode the video signal input from the demultiplexer during normal speed playback. do.

It will be described below with reference to the accompanying drawings.

2 is a block diagram showing a schematic configuration of a digital satellite image receiver according to the present invention. The channel unit 11 demodulates and digitally converts an input high frequency signal, and corrects an error inserted during transmission. Outputs the multiplexing unit 12 which separates the audio signal and the video signal from the digital signal input from the channel unit, and the digital video signal input from the demultiplexing unit 12 to be selectively stored in the memory unit 14. At the same time, the digital video signal input from the demultiplexing unit 12 or the digital video signal stored in the memory unit 14 and the digital audio signal stored in the memory unit 14 are decoded in MPEG according to the control signal from the control unit 17. A video / audio decoding unit 13, a memory unit 14 for storing a digital video signal applied to the video / audio decoding unit 13, and the ratio A video encoding unit 15 for encoding the decoded video signal input from the audio / audio encoding unit 13 in accordance with a TV broadcasting method (eg, NTSC, PAL), and the video / audio encoding unit 13 And an audio DAC unit 16 for PCM demodulation of the decoded audio signal, and a control unit 17 for controlling the operation of each device.

The operation and effects of the present invention will be described in detail.

First, the structure of a digital video signal compressed by the MPEG method will be described with reference to FIG. 2. FIG.

As shown in FIG. 2 (a), the MPEG compressed video signal includes a plurality of group of groups (GOP) and a sequence head (SEQUENCE HEADER: SH) indicating an entry point of each screen group. STREAM), and about 15 screens (about 0.5 seconds) are played from each GOP, and one GOP is a base screen as shown in FIG. One I image obtained by encoding the entire data, four P images encoded for forward prediction between the frames, and between the I image and the P image, are bidirectionally predicted from the two images (I, P). It consists of 10 B images, which are images that are forward and reverse prediction.

The digital video signals I, P, and B made as described above are sequentially stored in the order input to the memory unit 14 before being input to the video / audio decoding unit 13 and decoded. In the present invention, the memory unit 14 ) Stores only the I image (1 sheet) and the P image (4 sheets) under the control of the controller 17. Therefore, the amount of data stored in the memory unit 14 is reduced to 1/3 (5 pieces out of 15 pieces in total). In general, since the viewer requires a slow playback in order to watch a specific screen in detail, the viewer can provide a satisfactory picture quality even when playing 10 screens per second.

First, when playing at the normal speed, the control unit 17 outputs a control signal to each device through the control service to be reproduced at the normal speed by the TV broadcast signal in the order of input, thereby input to the channel unit 11 The high frequency signal is PQSK demodulated and converted into a digital signal. After the error occurred during transmission by the forward error correction (FFC) is corrected, the high frequency signal is input to the demultiplexing unit 12. The demultiplexing section 12 separates the digital signal input from the channel section 11 into a video signal and an audio signal. The separated video digital signal and the audio digital signal are respectively input to the video / audio decoding unit 13, and are respectively decoded. The video digital signals are input in the order of I, P, and B video signals as shown in FIG. First, I picture, which is a video signal that encodes a frame, is decoded, and then P picture, which is a forward predictive coded picture, is decoded based on the decoded I picture, and based on the decoded I picture, P picture, two signals (I, The B picture which is the bidirectional predictive encoded video inputted between P) is decoded in the input order, the next P picture is decoded based on the I picture which is the base screen, and the two B pictures provided therebetween are decoded as above. do. In this way, when the decoding of one screen group (GOP) is completed, the decoded video signal is inputted to the video encoder 15, and encoded according to the TV system, for example, NTSC or PAL system. Then, the digital audio signal input to the video / audio decoder 13 is decoded, and after the compressed information is decompressed, it is input to the audio DAC 16 and converted into a state (analog signal) that can be received by a TV.

Next, a case of reproducing the screen at a slow speed will be described with reference to the flowchart of FIG. 3. As described above, the high frequency input signal is demodulated in the channel unit 11 and the error inserted during transmission after digital conversion processing is corrected. The demultiplexing unit 12 is input to the demultiplexing unit 12 so as to be separated into a video signal and an audio signal. The digital video signal output from the demultiplexing unit 12 is stored in the memory unit 14 through the video / audio decoding unit 13, and the frame encoding image (I image) and forward reflection prediction of the digital video data are performed. Only the encoded image (P image) is stored, and the bidirectional predictive encoded image (B image) is not stored. The controller 17 receives a slow playback command from the viewer during the operation, and outputs a control signal to the video / audio decoding unit 13 to decode the data stored in the memory 14, whereby the video / audio decoding unit 13 Blocks the digital video signal input directly from the demultiplexing unit 12 and decodes the data (I picture and P picture) stored in the memory unit 14. That is, after decoding the I picture first, the P picture is decoded based on the I picture, and then output to the video encoding unit 15. The decoded video signal is converted into a TV broadcast signal by the video encoding unit 15. Is converted.

As described above, the present invention can reproduce the digital satellite video signal at a slow speed without increasing the memory size, and has an excellent effect of improving the practicality by reducing the price of the digital satellite broadcast receiver.

Claims (1)

In a digital satellite image receiver, A channel section for receiving high frequency signals, QPSK demodulation, converting them into digital signals, and correcting errors; A demultiplexer which separates the digital signal output from the channel unit into a video signal and an audio signal; Video / audio decoding digital video signals and audio signals of I, P, and B images input from the multiplexing unit, or decoding I and P images stored in a memory unit under control of the controller. A decoding unit, A memory unit for storing the I and P video signals of the digital video signal inputted from the demultiplexing unit through the video / audio decoding unit under control of the controller; A video encoding unit encoding the decoded digital video signal output from the video / audio decoding unit according to a TV broadcasting method; An audio DAC unit for converting the decoded audio signal input from the video / audio decoding unit into an analog signal; And a control unit for outputting a control signal to decode the data stored in the memory unit when the slow playback request is performed, and to decode the video signal input from the demultiplexer during normal speed playback. Digital satellite video receiver with slow playback.