KR100312713B1 - Device for caption broadcasting using digital broadcasting satellite - Google Patents

Abstract

PURPOSE: A device for caption broadcasting using a digital broadcasting satellite is provided to offer caption broadcasting by embedding a caption broadcasting decoder in a set-top box for digital broadcasting if a television receiver is not equipped with caption broadcasting function. CONSTITUTION: A device caption broadcasting using a digital broadcasting satellite comprises a caption data slice unit(100) for slicing only the caption data of an CC/EDS(Closed Caption/Extended Data Stream) from the output of an MPEG-2(Moving Picture Expert Group Layer-2) video decoder(60), a caption data decoding unit(110) for outputting caption signals by decoding the caption data, and a video signal mixing unit(120) for outputting video signals by mixing the caption signals output from the caption data decoding unit with the output of an STSC/PAL(National Television Standard Committee/Phase Alternation by Lines) encoder(70).

Description

Caption broadcasting device using digital broadcasting system

The present invention relates to a caption broadcasting apparatus using a digital broadcasting system. More particularly, in the case of a television receiver having no caption broadcasting function, a caption broadcasting decoder for caption broadcasting can be provided in a set top box for digital broadcasting. A caption broadcasting apparatus using a digital broadcasting system.

In general, a caption is translated into subtitles in Korean, and a character is displayed on a video screen such as a movie or a television, and has a function of supplementing the image. The contents of the video screen can be abbreviated and serviced for the hearing impaired, or translated and displayed in a foreign language can be used for language learning.

In other words, the Caption function is a function that translates a foreign language output as a voice signal into subtitles or provides a subtitle even if it is a native language. It is an add-on to television that enhances learning or is specifically considered for the visually impaired.

Caption broadcasts that are served to viewers using television are largely divided into open captions and closed captions. Open captions are subtitles that are always inserted with the video screen. On the other hand, closed captions insert caption data into empty sections of a video signal and transmit the caption data, and viewers can arbitrarily turn on / off the captions in a decoder having a caption function.

A representative caption broadcast method is a closed caption of the United States.

The feature of closed caption method is started by Resume Text Display (RTD) command and clears the current screen by TR (Text Restart) command. Then, the cursor moves to 1 row and 1 column to wait for input of caption command. Once entered, you exit the text mode. You can enter commands related to character positioning or return between the RTD command and the TR command.

Typically, this caption function is achieved by a caption processing circuit mounted inside the television set. That is, as shown in Fig. 1, a television with a caption processing circuit includes a signal tuning unit 2 and a frequency tuning unit for tuning and tuning a broadcast signal including a composite video signal received through an antenna 1, and a signal tuning unit 2; A video signal processor (3) for signal processing the video signal among the broadcast signals tuned by "), a voice signal processor (4) for signal processing the audio signal among the broadcast signals tuned by the signal tuner (2), and the video. A caption processing circuit 5 for slicing only the caption data carried in the vertical blanking period from the composite video signal of the signal processing section 3 for signal processing, and the video signal and caption processing circuit processed in the video signal processing section 3 ( 5) a video signal synthesizer 6 for synthesizing the closed caption video signal, a second amplifying unit 7 for amplifying the audio signal processed by the audio signal processor 4, and a first synthesizer 6 Synthesized synthesized video signal amplification The first amplifying unit 8, a cathode ray tube 9a for visually displaying the composite video signal amplified by the first amplifying unit 8, and the synthesized audio signal amplified by the second amplifying unit 7. The speaker 9b is shown.

By the way, such a conventional caption processing circuit is generally mounted in addition to a high-performance television.

Particularly, in the case of a television without a reception function for the closed caption / extended data stream (CC / EDS), character data cannot be displayed and data cannot be received through a low speed data port.

Therefore, a consumer who purchases a general television has a contradiction in which a high-performance television must be separately purchased to obtain caption information.

When caption information is to be viewed using an external caption signal processing apparatus, the external caption signal processing apparatus processes the caption signal among the broadcast signals received through a separate broadcast signal receiver and outputs the synthesizer to the synthesizer to output the broadcast signal of the TV. By combining with the user, there is a problem that the user must further include a separate broadcast signal receiving apparatus to watch the caption information.

Accordingly, the present invention has been made to solve the above problems, and in the case of a television receiver without a caption broadcasting function, a digital broadcasting capable of providing caption broadcasting by embedding a caption broadcasting decoder for caption broadcasting in a set top box for digital broadcasting is provided. The purpose is to provide a caption broadcasting apparatus using a system.

1 is a schematic block diagram of a conventional TV with a built-in caption processing circuit,

2 is a block diagram showing a preferred embodiment of a caption broadcasting apparatus using a digital broadcasting system according to the present invention;

3 is an exemplary diagram illustrating syntax of a transport stream packet of an MPEG-2 TS.

<Description of the symbols for the main parts of the drawings>

10 parabolic antenna 20 tuning unit

30: demodulation unit 40: forward error correction unit

50: demultiplexer 60: MPEG-2 video decoder

70: NTSC / PAL Encoder 80: MPEG-2 Audio Decoder

90: audio digital-analog converter 100: caption data slice

110: caption data decoding unit 120: video signal mixing unit

In order to achieve the above object, a caption broadcasting apparatus using a digital broadcasting system according to the present invention receives digital video data compressed with digital video data and digital audio data, and converts it into an analog video signal and an audio signal. A system, comprising: a signal tuner for tuning a transport packet carrier by impedance matching; A demodulator for separating the digital broadcast transmission packet through digital channel demodulation from the transmission packet carrier; A demultiplexer for separating and demultiplexing video data and audio data compressed to a predetermined standard in the transmission packet; A video decoder for decoding the compressed video data and restoring the original digital data; A composite video signal encoder for encoding a video output of the video decoder into a television video composite video signal of a predetermined standard for display through a television receiver; A caption data slicer which slices only caption data at an output of the video decoder; A caption data decoder for decoding the caption data and outputting an analog caption signal; And a video signal mixing unit for mixing the caption signal output from the caption data decoder and the composite video signal output from the composite video signal encoder and outputting the mixed video signal to the television receiver.

The digital broadcast transport packet may be an MPEG-2 TS packet, and the caption data is a closed caption / extended data stream (CC / EDS).

Hereinafter, a preferred embodiment of a caption broadcasting apparatus using a digital broadcasting system according to the present invention will be described with reference to the accompanying drawings.

Recently, with the advent of the digital era, various digital technologies have been actively introduced into the broadcasting field. In particular, the development of audio / video compression technology for processing data in a digital format has become a direct background to realize digital broadcasting.

In addition, digital broadcasting has been helped by the development of communication satellites and broadcasting technologies, and the boundaries between the existing telecommunications and computer industries, as well as the broadcasting and film industries have been broken down, and the elements recognized as characteristics of each field are different fields. It can be said to be the result of the phenomenon of expanding.

Digital Direct Broadcasting Satellite (DBS) broadcasting system technology, which is the basis of digital broadcasting system, is based on the MPEG-2 (ISO / IEC JTC / SC2 / WG11) of the International Standard Organization (Moving Picture Experts Group-2) system. (ISO / IEC 13818-1) and video (ISO / IEC 13818-2) and audio (ISO / IEC 13818-3) have been standardized, the European Digital Video Broadcasting (DVB) challenge and the European Telecommunications Standards Standardization of digital TV systems (satellite, terrestrial, cable), including service information, scrambling, channel coding, and modulation, by the Institute has been successfully completed. Realization and sharing of technology is an international trend.

A brief history of the major digital broadcasting services currently in service is as follows: In mid- 1994, PrimeStar Partners of the United States applied Digichipher technology, similar to MPEG, to a conventional DSB using Primestar DBS ( With the launch of PrimeStar DBS), DirecTV / USSB (DirecTV / United States Satellite Broadcasting Company) also launched digital DBS service using MPEG-1 video technology, and digital broadcasting service has been in full swing.

Since early 1996, Tee-Comm's Alphastar and Echostar Comm's DISH Network, which has applied MPEG-2 technology and DVB standards, have been in service. Japan and Europe are actively participating in digital broadcasting services using their respective communication satellites and unique digital broadcasting methods. In addition, Korea Telecommunication (KT) of Korea has begun digital broadcasting services using MPEG-2 technology and DVB standard through Koreasat in July 1996.

Advances in digital broadcasting technology not only provide advantages in terms of television broadcasting, such as efficient use of repeater bandwidth, improved video and audio quality, and miniaturization of receive antennas, but also enable data services, and the transmission signal is digital. Due to this, it can be easily connected and converged with other communication systems, computer systems, and different digital broadcasting systems, thereby creating a wide range of technical ripple effects.

2 is a block diagram showing a preferred embodiment of a caption broadcasting apparatus using a digital broadcasting system according to the present invention.

The digital broadcast receiver shown in Fig. 2 has a parabolic antenna 10, which is a conductor that radiates and absorbs radio waves, and a signal tuning for tuning transmission packet carriers by impedance matching in the radio waves received by the parabola antenna 10. A demodulator 30 that separates a transport packet from the transport packet carrier through quadrature phase shift keying demodulation (QPSK), and forward error correction (FEC) for the transport packet signal. A forward error corrector 40 for performing correction and a reverse error multiplexer coupled to the forward error corrector 40 to demultiplex MPEG-2 video data and MPEG-2 audio data from the output of the forward error corrector 40. A multiplexer (DEMUX) 50, an MPEG-2 video decoder 60 for decoding the MPEG-2 video data, and a video signal output from the MPEG-2 video decoder 60; Combined with the NTSC / PAL encoder 70 encoding the NTSC (Phase Alternation by Lines) method and the demultiplexer 50 to decode the MPEG-2 audio data for display through the NTSC (National Television Standard Committee) or PAL (Phase Alternation by Lines) scheme. Audio-to-analog conversion (DAC) to perform an MPEG-2 audio decoder 80 and an output of the MPEG-2 audio decoder 80 through a speaker. A caption data slicer 100 which slices only caption data of CC / EDS (Closed Caption / Extended Data Stream) at the output of the MPEG-2 video decoder 60 and the caption data Caption data decoding unit 110 for outputting a caption signal, and a video signal mixing unit for mixing and outputting the caption signal output from the caption data decoding unit 110 and the output of the NTSC / PAL encoder 70. It consists of 120.

The operation of the preferred embodiment of the caption broadcasting apparatus using the digital broadcasting system according to the present invention configured as described above will be described in detail.

In general, a parabolic antenna having a directivity determined by an aperture area and a focal length is widely used as a digital broadcasting antenna, which reflects radio waves from parabolic surfaces and emits almost plane waves in the direction of the aperture surface. As sharp directivity and high gain are obtained, it is most widely used as a microwave antenna for satellite broadcasting.

In describing the performance of the present invention, the process of the present invention will be described with reference to the MPEG-2 TS (MPEG-2 Transport Stream) method among digital broadcasting methods to help understand the present invention.

Currently, digital broadcasting is performed using MPEG-2 TS, which is a DVB method using a transport stream packet according to MPEG-2, and Direc TV, which is a non-DVB (Non-DVB) method, which does not use a TS packet. Although largely divided, it is clear that the scope of the present invention is not limited to the MPEG-2 TS method due to the description of the present invention based on the MPEG-2 TS method.

A syntax of a TS packet that can be used as a transport packet of the present invention will be described with reference to FIG. 3.

3 is an exemplary diagram illustrating syntax of a transport stream packet (ie, TS packet) of MPEG-2 TS.

The TS packet is composed of 188 bytes, and is composed of a header that provides advance information on the TS packet and a payload, which is a part where actual data is recorded. The header is a sync byte. Transport error indicator, start indicator, transport priority, packet identifier (PID), scrambling control, adaptation field control ), A predetermined bit is allocated to each of the continuity counter and the adaptation field to provide related information.

The two bits of the scrambling control bit (scrambling control bit) is a bit indicating whether the scrambling of the payload, if the bit combination is' 00 'indicates that the payload is not scrambled, while the remaining bit combination, that is,' 01 ',' 10 ', and' 11 'generally mean that the payload is scrambled and may be set by user-defined.

A 2-bit adaptation field control bit is a bit indicating whether to use an adaptation field. If the bit combination is '01', it indicates that there is no adaptation field but a payload exists. '10' indicates that there is no payload but an adaptation field exists, and '11' indicates a bit indicating that both a payload and an adaptation field exist.

On the other hand, the packet identifier (PID) is a bit indicating the type of the packet as known from the name, and 13 bits are allocated, thereby providing identification of 8192 (ie, 2 ¹³ = 8192) different packets.

First, when the tuning unit 20 tunes the transmission packet carrier from the radio wave received by the parabola antenna 10 by impedance matching, the demodulation unit 30 performs the transmission packet carrier through QPSK demodulation, which is a representative digital modulation and demodulation scheme. The MPEG-2 Transport Stream is separated from the MPEG-2 Transport Stream, and the forward error correction unit 40 performs forward error correction on the transport packet to correct an error in its own error correction scheme in the transmitted data. .

Thereafter, when the demultiplexer 50 separates and demultiplexes MPEG-2 video data and MPEG-2 audio data from the transport packet with reference to the header of the transport packet on which forward error correction has been performed, the MPEG-2 video decoder As the 60 decodes the MPEG-2 video data and applies it to the NTSC / PAL encoder 70, the NTSC / PAL encoder 70 displays the output of the MPEG-2 video decoder 60 through a television receiver. In order to encode using NTSC or PAL, the MPEG-2 audio decoder 80 decodes MPEG-2 audio data and applies it to the audio digital-to-analog converter 90. The audio digital-to-analog converter 90 The output of the MPEG-2 audio decoder 80 is digital-analog converted and then output through a speaker.

In this case, when the caption data slice unit 100 slices only caption data of CC / EDS (Closed Caption / Extended Data Stream) from the output of the MPEG-2 video decoder 60, the caption data decoding unit 110 may capture the caption. As the caption signal is output by decoding the data, the image signal mixer 120 mixes the caption signal output from the caption data decoder 110 with the output of the NTSC / PAL encoder 70 to display a television receiver (not shown). ).

Terminologies used herein are terms defined in consideration of functions in the present invention, which may vary according to the intention or customs of those skilled in the art, and the definitions should be based on the contents throughout the present application. will be.

In addition, since the present invention has been described through the preferred embodiment of the present invention, in view of the technical difficulty aspects of the present invention, those having ordinary skill in the art can easily be different from another embodiment of the present invention. Since modifications may be made, it is obvious that both the embodiments and modifications cited in the above description belong to the claims of the present invention.

As described in detail above, in a digital broadcasting system for receiving digital video data compressed with digital video data and digital audio data and converting them into analog video signals and audio signals, the transmission packet carriers are tuned by impedance matching. A signal tuning unit to make; A demodulator for separating the digital broadcast transmission packet through digital channel demodulation from the transmission packet carrier; A demultiplexer for separating and demultiplexing video data and audio data compressed to a predetermined standard from the transport packet; A video decoder for decoding the compressed video data and restoring the original digital data; A composite video signal encoder for encoding a video output of the video decoder into a television video composite video signal of a predetermined standard for display through a television receiver; A caption data slicer which slices only caption data at an output of the video decoder; A caption data decoder for decoding the caption data and outputting an analog caption signal; And a video signal mixer which mixes the caption signal output from the caption data decoder and the composite video signal output from the composite video signal encoder and outputs the mixed video signal to the television receiver. According to the present invention, there is an advantage that a caption broadcast can be easily viewed even by using a television receiver having no caption broadcast function.

Claims (3)

A digital broadcasting system for receiving digital video data compressed with digital video data and digital audio data, and converting the digital video data into analog video signals and audio signals, comprising: a signal tuning unit for tuning a transport packet carrier by impedance matching; A demodulator for separating the digital broadcast transmission packet through digital channel demodulation from the transmission packet carrier; A demultiplexer for separating and demultiplexing video data and audio data compressed to a predetermined standard in the transmission packet; A video decoder for decoding the compressed video data and restoring the original digital data; A composite video signal encoder for encoding a video output of the video decoder into a television video composite video signal of a predetermined standard for display through a television receiver; A caption data slicer which slices only caption data at an output of the video decoder; A caption data decoder for decoding the caption data and outputting an analog caption signal; And a video signal mixing unit which mixes the caption signal output from the caption data decoder and the composite video signal output from the composite video signal encoder and outputs the mixed video signal to the television receiver. . The caption broadcasting apparatus according to claim 1, wherein the transport packet for digital broadcasting is an MPEG-2 TS packet (Moving Picture Experts Group-2 Transport Stream packet). The caption broadcasting apparatus according to claim 1, wherein the caption data is a closed caption / extended data stream (CC / EDS).