KR101588738B1 - A method for processing a digital broadcast signal and a digital broadcast receiver - Google Patents

Abstract

The present invention relates to a digital broadcasting signal processing method and a digital broadcasting receiver, and an example of a digital broadcasting receiver according to the present invention is a digital broadcasting receiver which tunes a specific channel and processes a first stream and a second stream, A tuner for receiving a digital broadcast signal including a stream; A channel decoder for demodulating and error-correcting the received digital broadcasting signal; A demultiplexer for demultiplexing the first stream and the second stream from the error-corrected digital broadcast signal; A first video decoder for decoding video data of the first stream; A buffer for receiving and temporarily storing the video data of the second stream while the video data of the first stream is being decoded; A control unit for stopping the decoding operation of the first video decoder and controlling the video data of the second stream stored in the buffer to be decoded and output if the error rate of the first stream is equal to or greater than a threshold value; A second video decoder for decoding video data of a second stream received from the buffer; An audio decoder for decoding audio data of each stream in synchronization with the video data to be decoded; And an output unit for outputting the decoded audio data and the video data.

According to the present invention, it is possible to adaptively process a digital broadcast signal transmitted in various transmission modes by switching the reception mode automatically according to a reception environment, to prevent a phenomenon such as a viewing interruption occurring in a mode switching process, It is possible to simplify and miniaturize the system configuration by sharing some of the configurations according to the mode in the process according to the mode, thereby reducing the cost and the system efficiency.

Digital broadcasting signal, ISDB-T, 1seg, 12seg, receiving sensitivity

Description

TECHNICAL FIELD [0001] The present invention relates to a digital broadcast signal processing method and a digital broadcast receiver,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcasting signal processing method and a digital broadcasting receiver, and more particularly, to a digital broadcasting signal processing method and a digital broadcasting receiver that adaptively transmit digital broadcasting signals according to reception environments.

The subject can be transmitted in various modes by a digital device having a photographing and sending function such as a camera. In order to consider the reception environment and the like, transmission in various modes at the transmitting end is considered.

However, the conventional receiver is configured to process a digital broadcast signal transmitted in a specific mode, so that a digital broadcast signal transmitted in a transmission mode other than the corresponding mode can not be processed. Particularly, since the digital broadcast signal transmitted in the specific mode has a high error rate, the state of the broadcast screen on which the digital broadcast signal is displayed is poor, which may cause inconvenience to viewers.

In order to solve such a problem, a method has been proposed that includes a configuration capable of processing all digital broadcast signals corresponding to each transmission mode. However, when such a method is used, the configuration of the receiver becomes complicated, and the cost of the receiver is increased, and the efficiency of the system is deteriorated.

Even if the receiver has all of the configurations corresponding to the respective transmission modes, the viewer must check the status of the screen and determine that the mode should be switched only when there is a mode switching command. The digital broadcasting signal adaptively transmitted according to the reception environment There is a problem that it can not be processed.

In addition, when switching from a specific mode to another mode, there is a problem that a screen is cut off due to a blank space, causing inconvenience to viewers.

In order to solve the above problems, it is an object of the present invention to provide a method for adaptively processing a digital broadcast signal transmitted in various transmission modes according to a reception environment and a digital broadcast receiver.

It is another object of the present invention to provide a method and a digital broadcasting receiver capable of automatically switching a reception mode corresponding to a transmission mode according to a reception environment and adaptively processing the reception mode.

It is another object of the present invention to prevent a viewing interruption phenomenon occurring in a receiving mode switching process.

The present invention aims to simplify and miniaturize the system configuration by sharing some of the configurations used in the process according to the reception mode, and to prevent the system efficiency from deteriorating along with the cost reduction thereof. .

The present invention relates to a digital broadcasting signal processing method and a digital broadcasting receiver, and an example of a digital broadcasting receiver according to the present invention is a digital broadcasting receiver which tunes a specific channel and processes a first stream and a second stream, A tuner for receiving a digital broadcast signal including a stream; A channel decoder for demodulating and error-correcting the received digital broadcasting signal; A demultiplexer for demultiplexing the first stream and the second stream from the error-corrected digital broadcast signal; A first video decoder for decoding video data of the first stream; A buffer for receiving and temporarily storing the video data of the second stream while the video data of the first stream is being decoded; A control unit for stopping the decoding operation of the first video decoder and controlling the video data of the second stream stored in the buffer to be decoded and output if the error rate of the first stream is equal to or greater than a threshold value; A second video decoder for decoding video data of a second stream received from the buffer; An audio decoder for decoding audio data of each stream in synchronization with the video data to be decoded; And an output unit for outputting the decoded audio data and the video data.

At this time, the control unit may control the first video decoder and the second video decoder not to operate at the same time.

The controller may control the first video decoder to operate when the error rate of the first stream is within the threshold again.

The buffer may output the video data of the second stream temporarily stored in the buffer to the FIFO so that the video data is decoded by the second video decoder under the control of the controller.

The control unit may control the video data of the second stream to be stored in the buffer while the video data of the first stream is being decoded by the first video decoder.

Also, the control unit controls the first video decoder so that second stream video data output from the first buffer after being temporarily stored in the buffer while the video data of the first stream is being decoded is not input to the second video decoder can do.

The first stream may be a 12-segment processed stream for one image.

Also, the second stream may be a stream processed by one segment for one image.

The tuner and the channel decoder can check the error rate of each stream so that data of a specific stream is processed according to reception sensitivity of the received digital broadcasting signal.

According to another aspect of the present invention, there is provided a method of processing a digital broadcast signal, the method comprising: receiving a broadcast signal including a first stream and a second stream that are processed in different ways for one image; Channel decoding the received digital broadcasting signal; Demultiplexing the first stream and the second stream from the channel-decoded broadcast signal; Decoding the video data of the first stream and simultaneously storing the video data of the second stream; Stopping decoding the video data of the first stream and decoding the video data of the temporarily stored second stream if the error rate of the first stream is greater than or equal to a threshold value; And outputting the decoded video data.

At this time, the video data of the first stream and the video data of the second stream may be decoded simultaneously and not output.

And control the video data of the first stream to be decoded if the error rate of the first stream is again within the threshold value.

If the error rate of the first stream is equal to or greater than the threshold value, the video data of the input second stream may be decoded so as to be output to the FIFO.

The first stream may be a 12-segment processed stream for one image.

Also, the second stream may be a stream processed by one segment for one image.

According to the digital broadcast signal processing method and digital broadcast receiver of the present invention,

First, there is an effect that a digital broadcast signal transmitted in various transmission modes can be adaptively processed according to a reception environment.

Secondly, there is an effect that the receiver automatically adapts the broadcast signal by switching the reception mode automatically according to the reception environment.

Third, there is an effect that it is possible to prevent a viewing interruption phenomenon generated in the reception mode switching process.

Fourth, by sharing some of the configurations used in the process according to the reception mode, it is possible to simplify and miniaturize the system configuration. In addition to the cost reduction, system efficiency There is an effect that it is also possible to prevent such a decrease.

Although the terms used in the present invention have been selected in consideration of the functions of the present invention, it is possible to use general terms that are currently widely used, but this may vary depending on the intention or custom of a person skilled in the art or the emergence of new technology. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term rather than the name of the term, and the contents of the present invention throughout the present invention.

Hereinafter, a method of processing a digital broadcast signal and a digital broadcast receiver according to the present invention will be described in detail with reference to the accompanying drawings. Here, for convenience of description, a description will be given of an example in which a digital broadcast signal is transmitted and received by an ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) method. It should be noted, however, that the present invention is not limited to the above method.

ISDB Concept of

FIG. 1 is a diagram for explaining the concept of an ISDB scheme according to the present invention, and FIG. 2 is a diagram illustrating an example of a multimedia service transmitted by a transport stream (TS) according to the present invention .

Referring to FIGS. 1 and 2, the ISDB relates to digital broadcasting. One channel having a bandwidth of 6 MHz is divided into 13 segments to transmit video, data, and audio. Here, it is possible to provide a fixed-frequency broadcast using 12 segments (12 seg) out of 13 segments and to provide a broadcast for a mobile device using the remaining 1 segment (1 seg). The latter is also known as the One Seg.

Such an ISDB is a new type of broadcasting for multimedia services, and it can be used for various types of digital contents including high definition television (HDTV), standard definition television (SDTV), sound, graphics, text, digital contents) can be systematically integrated and transmitted and received.

In FIG. 2, Example 1 shows a case in which high definition HDTV broadcasting and data broadcasting data are transmitted using 12 segments (12seg) for fixed reception, or three SDTV programs of normal picture quality available for four segments and data for data broadcasting are transmitted , And audio and data are transmitted using one segment (1seg) for mobile reception. In the latter case in Example 1, three different programs can be broadcast simultaneously on one channel.

In Example 2, one SDTV program and data broadcasting data are transmitted using 12 segments (12seg) for fixed reception and one SDTV program and data broadcasting data are transmitted using 1segment (1seg) for mobile reception This is an example of a case.

Finally, Example 3 is an example in which still picture and data are transmitted using 1 segment (1seg) for mobile reception.

As described above, the ISDB conforms to the MPEG-2 TS standard regarding the input / output of the system, which may include various kinds of services. And the digital contents integrated in the ISDB stream can be transmitted simultaneously with appropriate modulation scheme and data rate. Therefore, on the transmitting side, a control signal is used to inform the receiving side about multiplexing and modulation techniques. In addition, ISDB shall be capable of partial reception. This makes it possible to combine various systems suitable for the purpose of use and frequency conditions by appropriately selecting the number of segments on the transmitting side.

The concept of the ISDB will be described with reference to FIG. The video 101, the audio 102 and the data broadcasting data 103 are coded by the coder 104, 105 and 106 in accordance with the MPEG-2 system and are multiplexed by the multiplexer 107 into an MPEG-2 TS.

The coded MPEG-2 TS is modulated after error correction and transmitted through each medium.

For example, in the case of satellite broadcasting, the coded MPEG-2 TS is subjected to error correction using the RS code (Reed Solomon code) 204 and 188 in the error correction unit 108, Modulated and transmitted via the satellite 110. [

In the case of cable broadcasting, the coded MPEG-2 TS is error-corrected using the RS code of (204, 188) in the error correction unit 111, modulated by the modulation unit 112 in the 64 QAM manner, .

In the case of terrestrial broadcasting, the coded MPEG-2 TS is transmitted to the error correction unit 114 through the RS codes 204 and 188 and convolutional codes (1/2, 2/3, 3/4, 5/6, 7/8) and then modulated by a segmented orthogonal frequency division multiplexing (OFDM) scheme in the modulator 115 and transmitted through the antenna 116. [

In the following description, for the sake of convenience of description, ISDB-T (errestrial) for terrestrial broadcasting will be mainly described, and detailed description of satellite broadcasting and cable broadcasting will be omitted.

The ISDB-T broadcasting system uses the OFDM scheme as a modulation scheme to construct SFN (Single Frequency Networks) for robustness of a signal, and uses a segment structure to enable extensibility and partial reception . Transmission and Multiplexing Configuration Control (TMCC) technology can also be used to borrow time interleaving techniques for portable or mobile reception and to ensure flexibility and versatility.

ISDB The basic structure of -T

FIG. 3 is a diagram for explaining an example of layer transmission and partial reception through multiplexing and spectrum of ISDB-T according to the present invention, and FIG. 4 is a diagram for explaining a modulation scheme of ISDB-T according to the present invention Fig.

FIG. 1 briefly explains the concept of the ISDB scheme. Hereinafter, the structure in which broadcast signals are transmitted and received according to the ISDB-T scheme will be described in more detail.

ISDB-T uses MPEG-2 for source coding for digital broadcast signals to be transmitted. In addition, the RF transmission channel uses the OFDM scheme. Here, the transmission bandwidth is 5.6 MHz, which is suitable for transmission on a 6 MHz channel.

Three different services with different transmission parameters can be transmitted simultaneously over one transport channel. This approach is called hierarchical transmission. That is, ISDB-T can select transmission parameters independently for each layer layer. Therefore, the receiver can flexibly edit and receive the multiplexed program according to the reception condition.

The ISDB-T multiplexes each data to be transmitted, for example, an audio program, an HDTV program, an SDTV program, data broadcasting data, and the like, and is transmitted to the receiving side in an OFDM spectrum.

As described above, ISDB-T uses a transmission scheme called BST (band segmented transmission) -OFDM based on OFDM, and will be briefly described with reference to FIG. 4 attached hereto.

Referring to FIG. 4, the channel has a bandwidth of 6 MHz, the number of OFDM segments in one OFDM stream is 13 in the case of a wide band ISDB-T, and the number of OFDM segments in a narrow band ISDB- 1 " or " 3 " Thus, the bandwidth of one OFDM segment is 6/14 MHz, i.e., 429 kHz. At this time, each OFDM segment has the same structure.

The multiplexing and spectrum of the ISDB-T according to the present invention will be described with reference to FIGS. 3 and 4 as follows.

The ISDB-T scheme is broadband ISDB-T scheme and narrowband ISDB-T scheme. And each is transmitted to wide band receiver 310 and narrow band receiver 320 and processed.

First, the wideband ISDB-T scheme will be described as follows. The first spectrum is where the multiplexed audio program and the HDTV program are formed in the band 330 of 5.6 MHz. At this time, the spectrum is composed of a total of 13 OFDM segments and transmitted to the wideband receiver 310. One OFDM segment 331 located in the center of the spectrum is transmitted to the narrowband receiver 320.

The second spectrum is a multiplexed audio program, an SDTV program for mobile reception and an SDTV program for fixed reception in a band 340 of 5.6 MHz. At this time, the spectrum is composed of 13 OFDM segments in total, and the wideband receiver

Next, the narrowband ISDB-T scheme will be described as follows. The first spectrum is a case where only one audio program is formed in the band 350 of 429 kHz. At this time, the spectrum is composed of only one OFDM segment and is transmitted to the narrowband receiver 320.

The second spectrum is a case where multiplexed audio programs and data (for data broadcasting) are formed in a band 360 of 1.3 MHz. At this time, the spectrum is composed of a total of three OFDM segments and is transmitted to the narrowband receiver 320.

However, the OFDM segments formed by the robust band ISDB-T scheme can also be transmitted to the wideband receiver 310. [

The above-mentioned FIG. 3 also includes the concept of partial reception. For example, it can be seen that not all of the OFDM segments in the spectrum of the wideband ISDB-T are transmitted in one set to the wideband receiver 310, but some of them are transmitted to the narrowband receiver 320.

Partial reception of broadcast spectrum is a special case of layer transmission. As described above, one OFDM spectrum is composed of 13 segments. If the range of influence of the transmission parameters is limited to one OFDM segment, that segment may be received independently of the other 12 segments. In particular, the narrow band receiver 320 is capable of receiving one OFDM segment as described above in the form of a complete signal.

Regarding partial reception, limiting the range of frequency interleaving on the transmitted signal into one segment allows the segment to be separated independently from the other segments. With this method, a partial reception of a service included in a transmission channel is enabled by a narrow band receiver 320 having one OFDM segment bandwidth. Only one segment is assigned to partial reception, and this must be located in the middle of the OFDM segments.

The multiplexing in the ISDB-T system conforms to the specifications of the MPEG-2 system. For hierarchical multiplexing in ISDB-T, basically, a single TS should be transmitted on the transmission channel of a given bandwidth regardless of whether or not layer transmission is used. Therefore, separation and combination of TS is necessary, and this processing is performed on both the transmitting side and the receiving side. Since the signal for partial reception is part of a full channel signal, only a portion of the TS is used for partial reception.

Hereinafter, channel coding will be described.

FIG. 5 is a block diagram illustrating channel coding according to the present invention. Referring to FIG.

Basically, channel coding is provided in three paths, with respect to layer coding.

A remultiplexer 501 allows the transport stream TS to be remultiplexed prior to OFDM framing so that it can be sorted into data segments.

The outer coder 502, including the RS code applied to each transport stream packet, allows the receiver to correct errors for eight erroneous bytes in the transport stream packet.

The splitter 503 serves to distribute the transport stream packets through the outer coder 502 to each path as described above.

Hereinafter, each component according to each path will be described in common. An energy dispersal 504 adds a pseudo random binary sequence (PRBS) to the data stream to ensure a sufficient number of binary changes.

When the delay adjustment 505 and the byte-wide interleaver 506 depend on two transmission parameters, modulation and code rate, the data streams of the three paths have different delays, Resulting from byte-wise interleaving and deinterleaving at the receiver. Thus, the delay adjustment can be performed in a coder to enable the delay of the receiver to be minimized. In addition, the byte-wise interleaver 506 distributes the adjacent data by rearranging the sequences.

As described above, the transport stream TS is remultiplexed prior to OFDM framing and is channel-coded by being aligned with a data segment. After channel coding, a pilot signal is inserted into the data to form an OFDM segment.

In ISDB-T, for each data segment, the transmission parameters for the OFDM carrier modulation method and the length of time interleaving can be applied independently. Layer transmission of ISDB-T is possible by transmitting an OFDM segment group with different transmission parameters on one channel. Up to three layers (different segment groups) can be transmitted simultaneously on one channel. Also, partial reception can be regarded as one hierarchical layer.

FIG. 6 is an example of a block diagram illustrating a modulation process after channel coding according to the present invention.

The modulation is performed by a bit deinterleaver (601) and a mapper (602). The modulation includes a delay adjustment by bit-wise interleaving and a mapping of a constellation diagram of the modulation. Possible constellations in ISDB-T include differential quadrature phase shift keying (DQPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (16QAM) and 64QAM.

This layered data stream is synchronized and time-interleaved 603 and frequency interleaved 604 to form an OFDM frame 606. The OFDM frame unit 606 receives a data stream up to the frequency interleaving and receives a pilot and a control signal 605 in performing a framing process.

A guard interval is inserted through the IFFT 607 in the formed OFDM frame (608) and transmitted in the OFDM scheme.

The digital broadcasting receiver must be able to receive and process the MPEG-2 TS transmitted according to the transmission system and the transmission system as described above.

1st Example ( ISDB -T 12seg receiver)

7 is a diagram illustrating an example of an ISDB-T digital broadcast receiver according to the present invention.

7 shows an example of a configuration of a digital broadcasting receiver for processing a 12seg TS and includes a tuner unit 701, a channel decoder 702, a demultiplexer 705, a 12seg A / V decoder 709/706, And an output unit 708/710.

The tuner unit 701 tunes the corresponding channel when the receiver is turned on and a channel change request by a user or the like is received. When a user or the like makes a request for channel change or the like through a remote controller, the infrared detection unit (IR) (not shown) detects the channel and transmits the code to the system control unit 711. The system control unit 711 decodes the input key code and transmits a control signal to each component so that the key code can be operated according to the code. The tuner unit 701 cooperates with the center frequency of the changed channel, receives the carrier wave included in the center frequency of the set channel, converts the received carrier wave to an intermediate frequency, and transmits the intermediate frequency to the channel decoder 702.

The channel decoder 702 includes a demodulator 703 and an error corrector 704, and channel-decodes the received signal.

The demodulator 703 demodulates the signal included in the received intermediate frequency according to the modulation scheme of the signal.

The error correction unit 704 corrects the error when the error due to the obstacle and the reflected wave occurs in the process of transmitting the demodulated signal. The error correction unit 704 delivers a stream including the actual broadcast content included in the error-corrected signal to the demultiplexer 705. [

The demultiplexing unit 705 demultiplexes the video stream and the audio stream of the 12seg TS from the error-corrected received signal by the error correction unit 704.

The video decoder 706 receives and decodes the video stream of the demultiplexed 12seg TS.

The video processing unit 707 receives the decoded 12seg TS video stream from the video decoder 706 and converts the 12seg TS video stream into a format that can be output through the screen 708,

The audio decoder 709 receives and decodes the audio stream of the demultiplexed 12seg TS. At this time, the audio decoder 709 is processed in the video decoder 706, processed through the video processor 707, processed to be synchronized with the video data output through the screen 708, and outputted through the speaker 710.

According to the above-described procedure, the time required from the receiver to the video and audio output in response to the channel change request of the user or the like takes, for example, about 1 second.

Second Example ( ISDB -T 1 seg  receiving set)

8 is a diagram illustrating another embodiment of an ISDB-T digital broadcast receiver according to the present invention.

8 shows an example of the configuration of a digital broadcasting receiver for processing 1seg TS. The tuner unit 801, the channel decoder 802, the demultiplexer 806, the 1seg A / V decoder 810/807, And an output unit 809/811.

The tuner unit 801 tunes the corresponding channel when the receiver is turned on and a channel change request by a user or the like is received. When a user or the like makes a request for channel change or the like through a remote controller, the infrared detection unit (IR) (not shown) detects the request and transmits the code to the system controller 812. The system controller 812 decodes the input key code and transmits a control signal to each component so that the key code can be operated according to the code. The tuner unit 801 cooperates with the center frequency of the changed channel, receives the carrier wave included in the center frequency of the set channel, converts the received carrier wave to an intermediate frequency, and transmits the intermediate frequency to the channel decoder 802.

The channel decoder 802 includes a demodulator 803, a time interleaver 804, and an error corrector 805, and channel-decodes the received signal.

The demodulation unit 803 demodulates the signal in accordance with the modulation scheme of the signal included in the transmitted intermediate frequency.

The time de-interleaver 804 repeatedly and sequentially extracts and assembles the specific broadcast contents loaded in the demodulated OFDM signal at a repetitive sequential time interval in the demodulator 803. [

The error corrector 805 corrects the error when an error caused by the obstacle and the reflected wave occurs in the transmission process of the signal assembled by the time interleaver 805 after being demodulated. The error correction unit 805 delivers a stream including the actual broadcast content included in the error-corrected signal to a demultiplexer 806. [

The demultiplexing unit 806 demultiplexes the video stream and the audio stream of the 1seg TS from the error-corrected received signal by the error correction unit 805.

The video decoder 807 receives and decodes the video stream of the demultiplexed 1seg TS.

The video processing unit 808 receives the 1seg TS video stream decoded by the video decoder 807 and converts and processes the 1seg TS video stream so that the 1seg TS video stream can be displayed in accordance with the format that can be output through the screen 809,

The audio decoder 810 receives and decodes the demultiplexed 1seg TS audio stream. The audio decoder 810 is processed by the video decoder 807 and processed through the video processor 808 to be synchronized with the video data output through the screen 809 and outputted through the speaker 811.

According to the above-described process, the time required from the receiver to the video and audio output in response to the channel change request of the user, for example, takes about 4 seconds, for example.

Third Example ( ISDB -T 1 seg / 12 seg  receiving set)

A digital broadcasting receiver for receiving and processing an ISDB-T 12seg TS in the first embodiment, and a digital broadcasting receiver for receiving and processing an ISDB-T 1seg TS in the second embodiment. The above-described first and second embodiments exemplify and describe a dedicated receiver for each TS.

For example, in order to receive 1seg TS and 12seg TS at the same time, it is possible to simultaneously produce a final image by providing two tuners and decoders. However, in this case, a hardware configuration corresponding to twice the receiver configuration according to each of the above-described embodiments is required, and the problems mentioned in the related art also occur.

Accordingly, in the following description, a digital broadcast receiver configured to simultaneously receive 1seg TS and 12seg TS and solve the problems of the related art will be described.

That is, according to the present invention, when a problem such as deterioration of image quality of 12 seg broadcasting occurs due to deterioration of reception sensitivity due to reception environment while listening to a 12 seg broadcasting which is basically capable of high quality broadcasting, the mode is automatically switched, To be broadcasted. In addition, the redundant components are shared with each other so that the receiver configuration can be reduced in size and simplicity, and the efficiency of the system is not degraded.

9 is a diagram illustrating another embodiment of an ISDB-T digital broadcast receiver according to the present invention.

FIG. 9 shows an example of a configuration of a digital broadcast receiver for processing a 1seg TS / 12seg TS, and one receiver can process all of the 1seg TS / 12seg TSs.

9, the digital broadcasting receiver includes a tuner unit 901, a channel decoder 902, a demultiplexer 906/907, a video decoder 909/910, and an output unit 912/914 .

The tuner unit 901 tunes the corresponding channel when the receiver is turned on and a channel change request by a user or the like is received. The tuner unit 901 cooperates with the center frequency of the changed channel, receives the carrier wave included in the center frequency of the set channel, converts it to an intermediate frequency, and transmits the intermediate frequency to the channel decoder 902. When a user or the like makes a request for channel change or the like through a remote controller, the infrared detection unit (IR) (not shown) detects the request and transmits the code to the system controller 915. The system controller 915 decrypts the input key code and transmits a control signal to each component so that operation corresponding to the code can be performed.

The channel decoder 902 includes a demodulator 903, a time interleaver 904 and an error corrector 905. The channel decoder 902 channel-decodes a signal of an intermediate frequency transmitted through the tuner 901. The channel decoder 902 may be directly input to the error corrector 905 without going through the time interleaver 904 through the demodulator 903 when processing 12seg TS.

The channel decoding process will now be described. The demodulator 903 demodulates the signal included in the transmitted intermediate frequency according to the modulation scheme of the signal. The time de-interleaver 904 repeatedly and sequentially extracts and assembles the specific broadcast contents carried in the repetitive sequential time intervals in the OFDM signal demodulated by the demodulator 903 in the case of 1seg TS. The error correction unit 905 corrects the error of the 12seg TS demodulated through the demodulation unit 903 or 1seg TS assembled by the time interleaver 904 after the demodulation by the demodulation unit 903, Lt; / RTI > The error correction unit 905 outputs a stream including the actual broadcast content included in the error-corrected signal, that is, a stream including all the 13seg broadcast contents including 1seg and 12seg, to the 1seg demultiplexer 906 and the 12seg station And transmits it to the multiplexing unit 907 at the same time.

The 1seg TS demultiplexer 906 receives the 1seg TS error-corrected and received by the error corrector 905, and demultiplexes the video stream and the audio stream from the received 1seg TS.

The 12seg TS demultiplexer 907 receives the error-corrected 12seg TS received by the error corrector 905, and demultiplexes the video stream and the audio stream from the received 12seg TS.

The 1seg video buffer 908 receives and temporarily stores the demultiplexed video stream in the 1seg TS demultiplexer 906. At this time, the 1seg video buffer 908 may store, for example, 3 seconds of video stream. Further, the 1seg video buffer 908 processes the video stream in a first input first output (FIFO) manner.

The 1seg video decoder 909 receives the video stream temporarily stored in the 1seg video buffer 909, decodes it, and outputs the decoded video stream.

The 12seg video decoder 910 receives the demultiplexed video stream in the 12seg TS demultiplexer 907, decodes it, and outputs the decoded video stream.

The video data decoded and output by the 1seg video decoder 909 and the 12seg video decoder 910 is converted into a format that can be outputted through the screen 912 in the video processing unit 911, .

The audio decoder 913 receives and demodulates the audio stream demultiplexed by the 1seg TS demultiplexer 906 and the 12seg TS demultiplexer 907 and outputs the decoded audio stream through the speaker 914. At this time, the audio decoder 913 is processed in the video decoder 909/910 so as to be synchronized with the video data outputted through the screen 912 via the video processor 911.

The 1seg stream input to the 1seg TS demultiplexer 906 is demultiplexed into 1seg video stream and 1seg audio stream. The demultiplexed 1seg video stream is stored in the 1seg video buffer 908, as described above. Here, if the viewer is watching 1seg video, the stream stored in the 1seg video buffer 908 is directly transmitted to the 1seg video decoder 909, and the 1seg audio stream is delivered to the audio decoder 913 and output .

However, even if the viewer sees the 12 seg video, the 1 seg video buffer 908 simultaneously or continuously stores the 1 seg stream. The reason for storing at the same time is to prevent a phenomenon such as a screen break due to the switching by transmitting 1seg TS to the 1seg video decoder 909 within a short time and decoding when switching from the 12seg viewing state to the 1seg viewing state.

Further, in the case of the audio decoder 913, efficiency reduction of the system is prevented by sharing them in the 1seg / 12seg processing. This is because the decoding start time of the audio stream is very short, and therefore, at the time when the reception of 1seg and 12seg is switched, whether the 1seg audio or the 12seg audio is used does not affect the entire decoding time.

The 12seg stream input to the 12seg TS demultiplexer 907 is demultiplexed into a 12seg video stream and a 12seg audio stream. Here, if the viewer is watching the 12 seg video, the 12 seg video stream is delivered to the 12 seg video decoder 910, and the 12 seg audio stream is delivered to the audio decoder and output.

The selected video decoder decodes the incoming video stream to produce the same video frames as the transmitted broadcast content.

The system control unit 915 checks the reception sensitivity according to the reception environment through the tuner 901 and the channel decoder 902. [ That is, the system control unit 915 determines the reception sensitivity of the TS from the error ratio of the TS to be error-corrected. At this time, the system control unit 915 determines whether the error rate of the TS is equal to or greater than a predetermined threshold, and controls the 1seg TS so that the 1seg TS can be processed because the reception sensitivity is lowered. That is, if the error rate is equal to or greater than the threshold value, the 1seg buffer 908 and the 1seg video decoder 909 are controlled so that the 1seg TS is decoded and output through the screen 912. On the other hand, when the error rate of the TS is less than the predetermined threshold value, the system control unit 915 controls the current state to be maintained or switch to the high-quality 12seg viewing state since the reception sensitivity is not lowered. That is, if the current 12seg viewing state, the 12seg TS is processed and outputted. If the current 1seg viewing state is present, the 12seg TS viewing state is switched to the 12seg viewing state to transmit the control signal so that the 12seg TS is processed and output. In the above, for example, the threshold value may be a case where the error rate is 10%.

Overall, the system control unit 915 allows the viewer to view a high-quality broadcast by switching from the 1seg viewing state to the 12seg viewing state by keeping the 12seg viewing state when the reception sensitivity is good according to the receiving sensitivity of the error-corrected TS, If the reception sensitivity is not good, the control is switched to the 1seg viewing state so that the 1seg broadcast having the normal image quality but the good reception ability is viewed rather than the image quality due to the lowered reception sensitivity. If the TS is received, the reception sensitivity is continuously checked, and the received screen is automatically switched according to the check result to provide the processed screen so that the broadcast can be continuously provided to the viewer without interruption of the screen. That is, even if the reception sensitivity is worse and the first sensitivity is changed from the 12 sec viewing state to the 1 se viewing state, if the reception sensitivity is improved again, the 12 sec viewing state can be switched again.

Digital broadcasting signal processing method

FIG. 10 is a flowchart illustrating a method of processing an ISDB-T digital broadcast signal according to the present invention.

Hereinafter, a process of processing a digital broadcast signal transmitted in an ISDB-T scheme will be described with reference to the configuration of a digital broadcast receiver configured according to an embodiment of the present invention, for example, in FIGS.

A specific channel is tuned to receive the digital broadcasting signal of the ISDB-T scheme through the tuner 901 (S1001).

The channel decoder 902 channel-decodes the digital broadcast signal received in step S1001 (S1002). Here, the channel decoding may include demodulation, time-interleaving, error correction, and the like, as described above.

In step S1002, the channel-decoded digital broadcast signal is demultiplexed into 1seg TS and 12seg TS (S1003).

The demultiplexed 12seg TS is decoded and the demultiplexed 1seg TS is temporarily stored in the buffer 908 (S1004). The video frame portion of the 12seg TS is decoded in the video decoder 910, and the audio frame portion is decoded in the audio decoder 913. Here, the decoding process for the 12seg TS and the storage process for the 1seg TS can be performed simultaneously.

In step S1004, the decoded 12seg video frame and the audio frame are synchronized with each other in step S1004.

The receiver checks the error rate of the 12seg TS after step S1003. That is, the receiver determines whether the error rate of the 12seg TS is equal to or greater than a predetermined threshold (S1006). The step S1006 may be performed simultaneously with the step S1004 or S1005. Here, the predetermined threshold is, for example, a case where the error rate is 10%.

As a result of the determination in step S1006, if the error rate of the 12seg TS is not equal to or greater than the threshold value, steps S1004 and S1005 are performed.

However, if it is determined in step S1006 that the error rate of the 12seg TS is greater than or equal to the threshold, the 1seg TS temporarily stored in step S1004 is decoded and decoded in step S1007. This is because if the error rate of the 12seg TS exceeds the threshold value, the quality of the image outputted due to the lowered reception sensitivity due to the reception environment is lowered, which may cause inconvenience to viewers.

In step S1004, the buffer 908 temporarily stores the 1seg TS and then FIFO (first input first output) when the storage capacity is exceeded. Accordingly, if the error rate is equal to or higher than the threshold value in step S1006, the 1seg TS is directly received from the buffer 908 and processed, thereby preventing a screen break due to the 1seg TS mode switching in the 12seg TS mode . Further, as described above, in the present invention, 12seg TS and 1seg TS, in particular, video frames are not processed at the same time. 9, the 1seg video decoder 909 and the 12seg video decoder 910 do not operate at the same time. However, since the time required for the data processing is short, the audio decoder 913 shares the audio data with respect to the 1seg TS and the audio data with respect to the 12seg TS, Is enough.

As described above, according to the present invention, the viewer automatically switches the viewing state according to the reception environment and adaptively processes the broadcasting contents so that the viewer can continue to receive broadcasting without interrupting the screen.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Modification is possible. Accordingly, the spirit of the present invention should be understood only in accordance with the following claims, and all equivalents or equivalent variations thereof are included in the scope of the present invention.

1 is a diagram for explaining a concept of an ISDB scheme according to the present invention,

2 is a diagram illustrating an example of a multimedia service transmitted by a transport stream according to the present invention;

3 is a diagram illustrating an example of multiplexing and spectrum of ISDB-T according to the present invention,

4 is a diagram illustrating a modulation scheme of ISDB-T according to the present invention,

5 is a diagram illustrating channel coding in accordance with the present invention,

6 is a diagram illustrating a modulation process according to the present invention,

7 is a diagram illustrating an example of an ISDB-T digital broadcast receiver according to the present invention.

8 is a diagram illustrating another embodiment of an ISDB-T digital broadcast receiver according to the present invention.

9 is a diagram illustrating another embodiment of an ISDB-T digital broadcast receiver according to the present invention, and FIG.

FIG. 10 is a flowchart illustrating a method of processing an ISDB-T digital broadcast signal according to the present invention.

Claims (15)

A tuner for tuning a specific channel and receiving a digital broadcast signal including a first stream and a second stream that are processed in a different manner for one image; A channel decoder for demodulating and error-correcting the received digital broadcasting signal; A demultiplexer for demultiplexing the first stream and the second stream from the error-corrected digital broadcast signal; A first video decoder for decoding video data of the first stream; A buffer for receiving and temporarily storing the video data of the second stream while the video data of the first stream is being decoded; A control unit for stopping the decoding operation of the first video decoder and controlling the video data of the second stream stored in the buffer to be decoded and output if the error rate of the first stream is equal to or greater than a threshold value; A second video decoder for decoding video data of a second stream received from the buffer; When the video data of the first stream is decoded, the audio data of the first stream is decoded in synchronization with the video data of the decoded first stream, and when the video data of the second stream is decoded, An audio decoder for decoding the audio data of the second stream in synchronization with the video data of the second stream to be decoded; And And an output unit for outputting the decoded audio data and the video data. The method according to claim 1, Wherein, And controls the first video decoder and the second video decoder not to operate at the same time. 3. The method of claim 2, Wherein, And controls the first video decoder to operate when the error rate of the first stream is within a threshold again. The method according to claim 1, The buffer includes: And the video data of the second stream temporarily stored in the second video decoder is decoded by the second video decoder under the control of the controller. The method according to claim 1, Wherein, The video data of the second stream is simultaneously stored in the buffer while the video data of the first stream is being decoded by the first video decoder. 6. The method of claim 5, Wherein, And controls the first video decoder so that the video data of the second stream temporarily stored in the buffer is not input to the second video decoder while the video data of the first stream is being decoded. The method of claim 1, Wherein the first stream comprises: A digital broadcast receiver wherein the stream is processed in 12 segments for one image. The method of claim 1, Said second stream comprising: A digital broadcast receiver in which one stream is processed with one segment. The method according to claim 1, The tuner and the channel decoder, Wherein the error rate of each stream is checked so that data of a specific stream is processed according to reception sensitivity of the received digital broadcasting signal. The method comprising: receiving a broadcast signal including first and second streams processed in different ways for one video; Channel decoding the received digital broadcasting signal; Demultiplexing the first stream and the second stream from the channel-decoded broadcast signal; Decoding the video data of the first stream and simultaneously storing the video data of the second stream; Stopping decoding the video data of the first stream and decoding the video data of the temporarily stored second stream if the error rate of the first stream is greater than or equal to a threshold value; When the video data of the first stream is decoded using one audio decoder, the audio data of the first stream is decoded in synchronization with the video data of the decoded first stream, and the video data of the second stream is decoded Decoding the audio data of the second stream in synchronization with the video data of the second stream to be decoded when the audio data is decoded; and And outputting the decoded audio data and video data. 11. The method of claim 10, Wherein the video data of the first stream and the video data of the second stream are simultaneously decoded and not output. 12. The method of claim 11, And controlling the video data of the first stream to be decoded if the error rate of the first stream is within the threshold again. 11. The method of claim 10, And if the error rate of the first stream is equal to or greater than a threshold value, the video data of the second stream is decoded so as to be decoded. 11. The method of claim 10, Wherein the first stream comprises: Wherein the digital video signal is a stream processed in 12 segments for one video. 11. The method of claim 10, Said second stream comprising: And a stream processed by one segment with respect to one video.

Images