KR20050023713A - Method And Apparatus for Re-multiplexing Tranports Stream in Digital Boardcast Receiver - Google Patents

Abstract

PURPOSE: A method and an apparatus for re-multiplexing a transport stream in a digital broadcast receiver are provided to enable a user to use various programs at the same time by outputting a plurality of received transport streams to various output units. CONSTITUTION: A digital tuner receives a digital broadcast signal and outputs at least two transport streams. A re-multiplexor receives a plurality of transport streams and processes them into one transport stream. A conditional access unit decrypts a re-multiplexed transport stream outputted from the re-multiplexor. A decoder de-multiplexes and decodes the decrypted transport stream. The re-multiplexor includes a plurality of filters(501-506,511-516), a plurality of processors(531-536) and a multiplexor(540). The filters separate a certain transport packet from the inputted transport streams. The processors process the separated transport packet. The multiplexor reassembles the transport packet processed by the processors and executes a time division multiplexing operation and thereby generates one transport stream.

Description

Method and Apparatus for Re-multiplexing Tranports Stream in Digital Boardcast Receiver}

The present invention relates to a digital broadcast receiving apparatus and method for receiving a digital broadcast signal and outputting a video and audio signal. More particularly, the present invention relates to a method and apparatus for remultiplexing a plurality of transport streams in a digital broadcast receiving apparatus using a conditional access unit necessary for encryption or the like.

Digital broadcasting services have begun in earnest through the video and audio compression technology of MPEG2, a high-efficiency video and audio compression technology. In the MPEG2 standard, a transport stream (hereinafter referred to as " MPEG2-TS ") for time-division multiplexing and transmitting a plurality of programs is defined in consideration of application to digital broadcasting. In conventional analog broadcasting, only one program can be broadcasted in one communication channel. In digital broadcasting using MPEG2-TS, time-division multiplexing of several programs (for example, four or four programs) is performed. It became possible to broadcast.

However, in the conventional analog broadcasting, the viewer can watch a desired program only by channel tuning through the tuner of the receiving terminal. In the digital broadcasting using MPEG2-TS, even after tuning a channel, the viewer can select a desired program among multiple programs transmitted by time division multiplexing. You need to select and isolate the program.

The program selection method in such MPEG2-TS or digital broadcasting using the same will be described below. MPEG2-TS is composed of a transport packet having a fixed length of 188 bytes, as shown in Figs. 1A and 1B. The transport packet is composed of a 4-byte packet header and a 184-byte data area. The packet header includes a 13-bit binary value starting from 8-bit sync information and has a binary value. Information such as packet identifier).

In addition, as shown in Fig. 1C, various data are separately stored and stored in units of transport packets in the data area. Here, as an example, various data transmitted as MPEG2-TS is shown when time-division multiplexing two programs through one channel. The program data is video / audio data of each program broadcasted by time division multiplexing, and specifically, video data of MPEG2 and audio data of MPEG2 corresponding to each program. PSI (Program Specific Information) data, which is program specification information, is information for facilitating selection of the program at a receiving terminal. The PSI includes transport packets such as a program association table (PAT), a program map table (PMT) corresponding to each program, a network information table (NIT), and the like.

These program data and PSI data are each assigned a unique PID as shown in Fig. 1C, and are time division multiplexed in units of transport packets. Through this, the PID of the transport packet can identify the type of data separately stored in the data area of the transport packet.

Fig. 2 shows the contents of the information described in the above PAT, PMT, and NIT and a connection relationship between them in the case of time division multiplexing and broadcasting two programs in one channel as MPEG2-TS. In FIG. 2, the PAT, PMT, and NIT have a hierarchical structure. PID = 0 is fixedly assigned to the PAT according to the MPEG2 standard. In addition, all programs broadcast by time division multiplexing and broadcasting in the corresponding MPEG2-TS have a program number as program identification information, respectively. This program number can be arbitrarily set by the broadcaster for each program.

The PAT describes the PID and the program number of the PMT corresponding to each of the time-division multiplexed and broadcast programs in the corresponding MPEG2-TS. As shown in Fig. 2, the PID of the PMT corresponding to program 1 with program number "1" (= "11") and the PID of PMT corresponding to program 2 with program number "2" ( = "12") is described. In addition, the PAT describes not only the PID of the PMT corresponding to the program but also the PID of the NIT. Since the program number "0" is fixedly assigned to the NIT according to the MPEG2 standard, the PID of the NIT corresponding to the program number "0" is described.

The PMT exists for each program and is hierarchically located under the PAT. Therefore, in the example shown in FIG. 2, PMT of program 1 and PMT of program 2 exist. In the PMT of each program, the PID of a transport packet for transmitting video and audio information of the program is described at the same time as the program number unique to each program.

Like the PMT, the NIT is hierarchically located below the PAT. The NIT describes physical information about the transmission path, but the details of the data structure are not defined in the MPEG2 standard and can be defined by the user. However, in digital broadcasting using MPEG2-TS, NIT is essential for realizing a program selection function to a receiving terminal. In general, at least information such as the number and frequency of the channel on which each program is broadcasted is described. In the NIT, as shown in Fig. 2, a program number unique to each program and a channel number on which the program is broadcast are described.

As described in the above description, the PAT and the PMT describe information on a program broadcast in the corresponding MPEG2-TS and are different for each channel. However, in the NIT, program numbers and channel numbers for programs not only broadcast on the corresponding MPEG2-TS (channel "61") but also programs of all other channels being serviced are described, respectively.

FIG. 3 briefly illustrates a structure of a set top box that receives a digital broadcast signal including the MPEG2-TS having the packet structure and extracts a video and audio signal. This figure shows, in particular, the case of using a conditional access unit, such as a media reader. The conditional access unit is a device that allows a user to watch a broadcast only for a user who purchased (or registered) the unit, such as a paid broadcast or a restricted broadcast for a specific person.

The digital tuner 310 of the set-top box 300 receives the digital broadcast signal transmitted through the broadcast transmission apparatus, and outputs it in the form of MPEG2 TS through a channel tuning process. The media reader 320 decrypts the transport stream output from the digital tuner 310 and delivers it to the MEPG decoder 330. Then, the MPEG decoder 330 de-multiplexes the input transport stream, separates it into an MPEG2 elementary stream of video and audio, and decodes and outputs the video and audio.

As described above, FIG. 3 illustrates a case in which one TS is decrypted through one set top box, but recently, a plurality of tuners are provided in one set top box so that multiple TS can be processed simultaneously so that multiple programs can be viewed simultaneously. The demand to increase is increasing. In this case, as many conditional access units are needed to decrypt multiple TS at the same time in one set-top box. As such, in order to use multiple conditional access units in one set-top box, there is a problem in that the user has to contract (or register) with the service provider by that number. Accordingly, there is a need to devise a method for simultaneously processing a plurality of MPEG TSs with only one conditional access unit.

An object of the present invention is to allow a user to use different programs at the same time by receiving a plurality of transport streams and output them to various output devices.

It is also an object of the present invention to provide an apparatus and method for decrypting a plurality of transport streams received using one conditional access unit in a set top box receiving a plurality of transport streams.

It is also an object of the present invention to provide an apparatus and method for remultiplexing a plurality of received transport streams in a set top box receiving a plurality of transport streams.

In order to achieve the above object, the apparatus according to the present invention comprises a digital tuner for receiving a digital broadcast signal and outputting two or more transport streams; A remultiplexer which receives the plurality of transport streams and processes them into one transport stream; A conditional access unit for decrypting a remultiplexed transport stream output from the remultiplexer; And an MPEG decoder for demultiplexing and decrypting the decrypted transport stream.

In order to achieve the above object, the method according to the present invention comprises the steps of: receiving a digital broadcast signal and outputting two or more transport streams; A second step of receiving the plurality of transport streams and processing the same into one transport stream; Decrypting a remultiplexed transport stream output from the remultiplexer; And a fourth step of demultiplexing and decrypting the decrypted transport stream.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram showing the configuration of a digital broadcast receiving apparatus including a remultiplexer according to the present invention. First, the broadcast signal 400 input through cable, terrestrial or satellite communication is converted into an intermediate frequency by an RF front end 401. This signal includes digital / analog common use tuners (402 and 403), an out-of-band receiver (404) and data-over DOCSIS (Digital / Analog Common Use Tuner) capable of processing both digital and analog broadcast signals. -Cable Service Interface Specification) respectively received by the receiver 405. The digital / analog tuners 402 and 403 are devices capable of receiving, for example, digital broadcast signals by ATSC (Advanced Television Systems Committee) cable or analog broadcast signals by general airwaves.

The analog video signals input to the digital / analog tuners 402 and 403 are output in CVBS format, and the respective analog audio signals are output in SIF format. In addition, each digital video and audio signal input to the digital / analog tuners 402 and 403 is, after channel tuning, an MPEG2 TS format including a multi-program or a single-program. Is output. Meanwhile, the signal input to the OOB receiver 404 is output as a quadrature phase shift keying (QPSK) signal after channel tuning, and the signal input to the DOCSIS receiver 405 is a quadrature amplitude modulation (QAM) signal after channel tuning. Is output.

Each analog video signal CVBS output from the digital / analog tuners 402 and 403 is input to analog video signal decoders 407 and 426 and output in the itu-trbt656 format. Each analog audio signal SIF output from the digital / analog tuners 402 and 403 is input to the MTS decoders (Multi-Channel Television Sound Decoder) 408 and 411 and then output as analog voice. The analog output voice is input to the analog to digital converters 409 and 413 and converted into digital signals.

Meanwhile, MPEG2 TS1 and TS2 including multiple programs or single programs output from the digital / analog tuners 402 and 403 are remultiplexed through an MPEG2 TS Re-multiplexer 415. This remultiplexed signal is in MPEG2 TS format containing multiple programs. This remultiplexed signal is input to a Media Cipher 416 corresponding to a Conditional Access Unit, and after decryption is decoded, the MPEG decoder over the PCI bus 420 is used. (MPEG Decoder; 423).

Each of the itu-trbt656 outputs output from the analog video signal decoders 407 and 426 and the respective digital audio outputs from the A / D converters 409 and 413 are dual channel MPEG encoders. 419, encoded by MPEG2 TS, and then input to MPEG decoder 423 through PCI bus 420.

The MPEG decoder 423 serves to process several MPEG2 TSs at the same time. The input to the MPEG decoder 423 includes two MPEG2 TS inputs including a single program output from the dual channel MPEG encoder 419 and one MPEG2 TS including multiple programs output from the media reader 416. The MPEG2 TSs input to the MPEG decoder 423 are first de-multiplexed into an MPEG2 elementary stream of video and audio, and then decoded and output from the MPEG decoder 423.

The set top box according to the present invention includes a plurality of tuners and a receiver. The purpose of the set top box is as follows. First, it may have a picture in picture function that allows a plurality of programs to be simultaneously viewed on one screen. In addition, it is possible to simultaneously watch another program received from the set-top box at another place by using a place where the set-top box is installed and a home network. In addition, the program can be recorded on the hard disk 425 while receiving and watching other programs.

As described above, the MPEG TS1 and MPEG TS2 output from the digital / analog tuners 402 and 403 are remultiplexed into an MPEG2 TS3 including multiple programs through the MPEG2 TS remultiplexer 415. This remultiplexing is necessary because MPEG2 TS1 and MPEG2 TS2, which contain respective digital video and audio input signals, cannot pass through the media reader 416 at the same time. If a plurality of TSs are to be decrypted at the same time in one set-top box, the number of conditional access units, that is, the media reader 416, is required. As described above, in order to use a plurality of conditional access units in one set-top box, the user has to contract (or register) with the service provider by the number thereof. However, using the multiplexing as proposed in the present invention, it is possible to simultaneously process a plurality of MPEG TSs with only one conditional access unit.

5 is a block diagram showing the internal configuration of a remultiplexer proposed in the present invention. The MPEG2 TS1 and MPEG2 TS2 received through the digital tuner 402 are PAT filters 501 and 511, PMT filters 502 and 512 and PES filters, respectively, according to the types of transport packets constituting the transport stream. 503 and 513, CAT filters 504 and 514, private filters 505 and 515, and NIT filters 506 and 516 are subjected to filtering.

First, the PAT filters 501 and 511 extract a header of a program association table (PAT) and a payload, which is a data area of the PAT, and write it to the buffer 520. The header and payload of the PAT constitute a transport packet whose PID in the header of Fig. 6A is "0x0000h". 6B shows the Program Association Section, which shows the structure of the payload portion of the PAT. The value of "table id" at the beginning of the Program Association Section has "0x00h" (h means hexadecimal). The structure of this PAT header and payload is defined in the standard specification of MPEG2 transport stream.

The PMT filters 502 and 512 extract a header of a program map table (PMT) and a payload, which is a data region of the PMT, and write the same into the buffer 520. The header and payload of the PMT constitute a transport packet in which the PID in the header of FIG. 6A has a value ranging from 0x0010h to 0x01FFEh. 6C shows a Program Map Section, which shows the structure of the payload portion of the PMT. The value of "table id" at the beginning of the program map section has "0x02h". The structure of the PMT header and payload is defined in the standard specification of the MPEG2 transport stream.

The PES filters 503 and 513 extract a header of a packetized elementary stream (PES) and a payload which is a data area of the PES, and write the same into the buffer 520. The header and payload of the PES constitute a transport packet whose PID in the header of FIG. 6A has a value in the range of 0x0010h to 0x01FFEh. Fig. 6D shows the PES_packet, which shows the structure of the payload portion of the PES. The value of "packet start code prefix" at the head of the PES packet has "0x0000001h". The structure of the header and payload of the PES is defined in the standard specification of the MPEG2 transport stream.

The CAT filters 504 and 514 extract a header of a conditional access table (CAT) and a payload which is a data area of the CAT and write the same to the buffer 520. The header and payload of the CAT constitute a transport packet whose PID in the header of FIG. 6A is "0x0001h". 6E shows a Conditional Access Map Section, which shows the structure of the payload portion of the CAT. The value of "table id" at the beginning of the Conditional Access Section has "0x021". The structure of the CAT header and payload is defined in the standard specification of the MPEG2 transport stream.

The private filters 505 and 515 extract payloads that are headers and data areas of the private section and write them to the buffer 520. The header and payload of the private section constitute a transport packet in which the PID in the header of FIG. 6A has a value ranging from 0x0010h to 0x01FFEh. FIG. 6F illustrates the payload structure of the private section. If necessary, the structure of FIG. 6F (a) or the structure of FIG. 6F (b) may be used. The value of "table id" at the beginning of the private section has a range of 0x40h to 0xFEh. The contents described in the " private data " portion of the private section are not defined in the MPEG-2 TS standard, and arbitrary data necessary for the broadcast transmission side can be described. However, parts other than "private data" are defined in the MPEG-2 TS standard. These private sections include the Entitlement Management Message (EMM) private section, which is a transport packet related to encryption, the Entitlement Control Message (ECM) private section, and a network information table (NIT), which is a transport packet related to network information, and other personal information. Data private section, which is a packet. However, since the NIT uses separate NIT filters 506 and 516, the private filters 505 and 515 process only the private section other than the NIT.

The NIT filters 506 and 516 extract a header of a network information table (NIT) and a payload, which is a data region of the NIT, and write the same to the buffer 520. The header and payload of the NIT are transport packets in which the PID in the header of FIG. 6A has a value ranging from 0x0010h to 0x01FFEh. In order to detect such a NIT, a private section having a PID recorded in the "Network PID" is found when the "program number" in the "payload" of the PAT is "0x0000h". The NIT has a structure of a private section in (b) of FIG. 6F, where the value of "table id" at the beginning has a value in the range of "0x40h-0xFEh".

A buffer 520 stores the transport packets classified from the respective filters and transmits the values to the corresponding processors. Transmission packets passing through the PAT filters 501 and 511 to the PAT processor 531, transmission packets passing through the PMT filters 502 and 512 to the PAT processor 532, and transmission packets passing through the PES filters 503 and 513 Respectively delivered to the PES processor 533. In addition, transmission packets passing through the CAT filters 504 and 514 are transmitted to the CAT processor 534, transmission packets passing through the private filters 505 and 515 to the private processor 535, and transmissions passing through the NIT filters 506 and 516. The packets are delivered to NIT processor 536 respectively.

The PAT processor 531 recombines two input PATs existing in MPEG2 TS1 and MPEG2 TS2, which contain respective digital video and audio input signals, into one output PAT. In FIG. 7A, the input TS1 and TS2 are stored in the buffer 520 after being passed through the PAT filters 501 and 511 and recombined by the PAT processor 531. The table displayed in the buffer 520 represents a combination of binary field names representing the field names, their values, and the number of bits of the stored data. This representational form is the same in the following FIGS. 7B to 7F.

Referring to the recombination process in the PAT processor 531, first, a "transport error indicator" value of each of the two input PATs is described as "OR bit operation" in the "transport error indicator". The payload unit start indicator describes the result of performing the “AND bit operation” on the “payload unit start indicator” values present in the two input PATs respectively. The OR bit operation of the "Transport prioty" value present in each of the two input PATs is described. In the "Adaptation field control", the result of OR bit operation of the "Adaptation field control" values present in each of the two input PATs is described, and in the "Continuity counter", it is first described as "0000" and the "Adaptation". If the value of the field control value is 01 or 11, the count is increased. In the section "Section length", the number of bytes from the field "Transport stream ID" to the last field "CRC32" is calculated and described, and in "Transport stream ID", a value for identifying a newly created transport stream is described. Version number is described by adding 1 to the Version number value existing in each of the two input PATs. In addition, the " Current next indicator " describes the result of performing the AND bit operation on the " Current next indicator " values respectively present in the two input PATs, and the " Section number " Increase the count by the number of sections. Last section number specifies the number of the last section of the recombined output PAT.

On the other hand, when "program number" is "0000 0000 0000 0000", it indicates NIT. Even if NITs of MPEG2 TS1 and MPEG2 TS2 exist, the two NITs are identical to each other if they are transmitted through the same transmission system. Therefore, only one of them may be used. Therefore, "network PID" describes a new number in the range of "0x0010h-0x01FFEh".

The program numbers of the two input PATs are rearranged to be described in one output PAT, so that there is no duplicate value. In addition, the "program map PID" is rearranged similarly so that there is no duplication. The "program number" described in the output PAT uses a value other than "0000 0000 0000 0000" so as to be distinguished from the "program number" of the NIT. In the "Program map PID", a new number is written in the range of 0x0010h to 0x01FFEh. The process of describing the "program number" and the "program map PID" is repeated by the total number of programs existing in the two input PATs. Fields other than the above are described as they are described in FIG. 7A.

The PMT processor 532 processes PMTs present in MPEG2 TS1 and MPEG2 TS2. In FIG. 7B, the input TS1 and TS2 are stored in the buffer 520 after being processed through the PMT filters 502 and 512, and are processed by the PMT processor 532. This processing process, unlike the PAT processing process, configures an output PMT for each of TS1 and TS2. This also applies to FIGS. 7C to 7F.

First, the PID of PMT and the "program number" of PMT are changed to values described in "PMT" PID "and" program number "determined by the recombination process by the PAT processor 531, respectively. In addition, the "PCR PID" included in the PMT is also described again in the range of 0x0010h to 0x01FFEh, but it is described so that there is no overlapping value. The PCR PID refers to an ID of a packet including a program clock reference (PCR) that is a reference clock when decoding a transport stream. Version number is described by adding 1 to the value present in the input TS1 or TS2. And, the "Elementary PID" included in the PMT is described again in the range of "0x0010h-0x01FFEh", but it is described so that there is no overlapping value. In addition, the "CA PID" included in the descriptor of the PMT is described again in the range of 0x0010h to 0x01FFEh, but it is described so that there is no duplicate value. The process of describing the " Elementary PID " and the " CA PID " is repeated by the number of elementary present on the corresponding PMT. The other fields describe the values existing in the input PMT as they are.

The PES processor 533 processes PESs existing in MPEG2 TS1 and MPEG2 TS2. In FIG. 7C, the input TS1 and TS2 are stored in the buffer 520 after being passed through the PES filters 503 and 513, and are processed in the PES processor 533. The PID in the header portion of the PES is changed to the " Elementary PID " value determined through the processing by the PMT processor 532. In the other fields, values existing in the input PES are described as they are.

The CAT processor 534 processes the CATs present in MPEG2 TS1 and MPEG2 TS2. In FIG. 7D, the input TS1 and TS2 are stored in the buffer 520 through the CAT filters 504 and 514 and processed by the CAT processor 534. Rewrite "CA PID" included in the descriptor of CAT, so that there are no duplicate values. This process is repeated as many as N loop descriptors on the CAT. In addition, "Version number" is described by adding 1 to the value present in the input CAT. In the other fields, values existing in the input CAT are described as they are.

The private processor 535 processes private sections existing in MPEG2 TS1 and MPEG2 TS2. In FIG. 7E, the input TS1 and TS2 are stored in the buffer 520 through the private filters 505 and 515, and are processed by the private processor 535. Among the payload part, the part below ＇Section length＇ may be composed of ＇Private data bytes＇ field as in (A) and plural fields as in (B). Will be according. If the private section is an EMM private section, the PID in the header portion of the private section is changed to the "CA PID" value determined through the processing by the CAT processor 534. In addition, in the case of the ECM private section, the PID in the header section of the private section is changed to the “CA PID” value determined through the processing by the PMT processor 532. In other fields, the value existing in the input private section is written as it is.

The NIT processor 536 processes two NITs existing in MPEG2 TS1 and MPEG2 TS2, respectively. In FIG. 7F, the input TS1 and TS2 are stored in the buffer 520 after being passed through the NIT filters 506 and 516, and are processed by the NIT processor 536. If transmitted through the same transmission system, two NITs are identical to each other, so only one of them may be processed and used. The PID in the NIT header is changed to a "network PID" value determined through the recombination process by the PAT processor 531. In addition, "Version number" is described by adding 1 to the value present in the input (TS1 or TS2). In the other fields, values existing in the input NIT are described as they are.

The multiplexer 540 transmits the transport packet processed by the PAT processor 531, the PMT processor 532, the PES processor 533, the CAT processor 534, the private processor 535, and the NIT processor 536. After reassembly and time division multiplexing, one transport stream including multiple programs, that is, MPEG2 TS is output. FIG. 8 illustrates an example of a process of time division multiplexing by reassembling a transport stream processed by each processor. The PAT packet 810 recombined through the recombination process by the PAT processor 531, the PMT packets 820 and 830 processed through the process by the PMT processor 532, and the private processor 535. The processed EMM packet 840 and the PES packets 851 to 857 containing the video signal and the audio signal are time-division multiplexed and output to the transport stream TS3. Although not shown, other CAT packets, NIT packets, ECM packets, and the like are also multiplexed.

9 is a flowchart illustrating the overall operation of the present invention. First, a plurality of digital broadcast signals are received through a plurality of digital tuners (S900). The received digital broadcast signal is output from the digital tuner as a plurality of transport streams and transmitted to the MPEG2 TS remultiplexer (S910). The plurality of transport streams are filtered through a corresponding filter for each transport packet type constituting the transport stream (S920). That is, the PATs on the plurality of transport streams are filtered through a PAT filter, a PMT through a PMT filter, and a PES through a PES filter. In addition, CAT filters CAT filters, EMM or ECM filters Private, and NIT filters NIT. A detailed description of the filtering process through the filters is described in detail in the description of the operation of each filter in the description of FIG. 5. Next, each filtered transmission packet is stored in a buffer (S930). The transport packet stored in the buffer is processed through the corresponding processor for each transport packet type (S940). A detailed description of the processing process through the processors is described in detail in the description of the operation of each processor in the description of FIG. 5. Next, time division multiplexing by reassembling the transport packets processed by the processor (S950). Transport packets processed by the respective processors exist in the form of separate packets, not transport streams, and thus need to be multiplexed. One transport stream generated through the remultiplexing is decrypted through a media reader (S960). Since only one transport stream can be input to one media reader in this manner, the plurality of transport streams are recombined into one transport stream in the above processes. Next, the decrypted transport stream is demultiplexed through an MPEG decoder (S970). As a result of the demultiplexing, video data and audio data are generated for each program. The video data and the audio data are decoded through the MPEG decoder (S980). Since the video data and the audio data are encoded and transmitted by using the MPEG2 compression scheme at the broadcaster, the user needs to decode the video data and the audio data in order to actually enjoy the video and the audio.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept are included in the scope of the present invention. Should be interpreted.

According to the present invention, the user can use a plurality of programs at the same time by using one set-top box.

In addition, according to the present invention, since a plurality of transport streams can be decrypted with only one conditional restriction unit, there is an effect of providing convenience and economic advantages to a user who wants to use a plurality of programs simultaneously.

In addition, according to the present invention, by remultiplexing the plurality of transport streams in the set-top box, there is an effect that can be used for various purposes.

1 illustrates an internal structure of a transport packet constituting a transport stream and a classification of transport packets for respective PIDs.

Fig. 2 shows the contents of information described in PAT, PMT and NIT and the connection relation therebetween.

3 is a block diagram briefly illustrating an internal configuration of a set top box according to the related art.

4 is a block diagram showing the configuration of a digital broadcast receiving apparatus including the MPEG2 TS remultiplexer according to the present invention.

5 is a block diagram showing the internal configuration of the MPEG2 TS remultiplexer proposed in the present invention.

6A shows the structure of the header portion of a transport packet in detail.

6B shows the structure of the Program Association Section in detail.

6C shows the structure of the Program Map Section in detail.

Figure 6d shows the structure of the PES \ packet in detail.

6E illustrates the structure of the Conditional Access Map Section in detail.

Figure 6f shows the payload structure of the private section.

FIG. 7A illustrates a process where input TS1 and TS2 pass through a PAT filter, are stored in a buffer, and are recombined in a PAT processor.

FIG. 7B illustrates a process in which the input TS1 and TS2 pass through the PMT filter, are stored in a buffer, and are processed by the PMT processor.

FIG. 7C illustrates a process in which the input TS1 and TS2 pass through the PES filter, are stored in a buffer, and are processed in the PES processor.

FIG. 7D illustrates a process in which the input TS1 and TS2 pass through a CAT filter, are stored in a buffer, and processed in a CAT processor.

FIG. 7E illustrates a process in which the input TS1 and TS2 pass through a private filter, are stored in a buffer, and are processed in a private processor.

7F illustrates a process in which the input TS1 and TS2 pass through the NIT filter, are stored in a buffer, and are processed in the NIT processor.

8 illustrates an example of a process of time division multiplexing by reassembling a transport stream processed by each processor.

9 is a flowchart illustrating the overall operation of the present invention.

Claims (22)

A digital tuner that receives a digital broadcast signal and outputs two or more transport streams; A remultiplexer which receives the plurality of transport streams and processes them into one transport stream; A conditional access unit for decrypting a remultiplexed transport stream output from the remultiplexer; And And a decoder for demultiplexing and decrypting the decrypted transport stream. The method of claim 1, wherein the remultiplexer is A plurality of filters for separating a specific transport packet from the input two or more transport streams through a corresponding filter; A plurality of processors for processing the separated transport packet in a corresponding processor; And And a multiplexer for generating one transport stream by reassembling and time-division multiplexing the transport packet processed by the processor. 3. The apparatus of claim 2, wherein the remultiplexer further comprises a buffer for storing the transport packets classified from the plurality of filters and delivering the stored values to a corresponding processor. . The method of claim 2, wherein the plurality of filters A first filter for separating only a transport packet (a) from the inputted two or more transport streams, the transport packet (a) containing information about a program contained in a transport packet currently being transmitted; A second filter for separating only the transport packet (b) from the inputted two or more transport streams containing information on which packet the video bit stream or audio bit stream is transmitted by; A third filter for separating only a transport packet (c) containing video bit stream or audio bit stream information from the input two or more transport streams; A fourth filter for separating only the transport packet (d) containing conditional reception information from the input two or more transport streams; A fifth filter for separating only the transport packet (e) containing encrypted bit string information from the input two or more transport streams; And And a sixth filter for separating only the transport packet (f) containing link information between the repeater and the program from the input two or more transport streams. The method of claim 2, wherein the plurality of processors A first processor for recombining a transport packet (a) containing information about a program included in a transport packet currently transmitted from among transport packets separated by the plurality of filters; A second processor for processing a transport packet (b) which contains information on which packet is transmitted by video bit stream or audio bit stream among transport packets separated by the plurality of filters; A third processor for processing a transport packet (c) containing video bit stream or audio bit stream information among transport packets separated by the plurality of filters; A fourth processor for processing a transport packet (d) containing conditional reception information among transport packets separated by the plurality of filters; A fifth processor for processing a transport packet (e) containing encryption bit string information among transport packets separated by the plurality of filters; And And a fifth processor for processing a packet (f) containing link information between a repeater and a program among transport packets separated by the plurality of filters. The method of claim 5, wherein the transport packet (a) is a PAT, Recombining the transport packet (a), Transport stream characterized in that the program number PID and program map PID of the output PAT are rearranged so that there are no duplicate values by rearranging the program number PID and the program map PID existing in the separated PATs. Device to remultiplex. The method of claim 5, wherein the transport packet (b) is PMT, The process of processing the transport packet (b), 2. An apparatus for remultiplexing a transport stream, wherein the " Elementary PID " and " CA PID " of the output PMT are rewritten so that there are no duplicate values. The method of claim 5, wherein the transport packet (c) is PES, The process of processing the transport packet (c), And changing the PID in the header portion of the output PES to the " Elementary PID " value determined through the processing by the second processor. The method of claim 5, wherein the transport packet (d) is CAT, The process of processing the transport packet (d), An apparatus for remultiplexing a transport stream comprising rewriting "CA PID" contained in a "descriptor" of an output CAT so that there is no duplicate value. The method of claim 5, wherein the transport packet (e) is a Private Section, The process of processing the transport packet (e), When the private section is an EMM, the PID in the header section of the output private section is changed and described as a "CA PID" value determined through a processing by the CAT processor. When the private section is an ECM, the PMT is described. An apparatus for remultiplexing a transport stream, characterized by changing a PID in a header portion of an output private section to a "CA PID" value determined through a processing by a processor. The method of claim 5, wherein the transport packet (f) is NIT, The process of processing the transport packet (f), And changing the PID in the output NIT header to a "network PID" value determined through a recombination process by the first processor. Receiving two digital broadcast signals and outputting two or more transport streams; Receiving the plurality of transport streams and processing the same into one transport stream; Decrypting the remultiplexed transport stream output from the remultiplexer; And Demultiplexing and decrypting the decrypted transport stream. 13. The method of claim 12, wherein processing into one transport stream Separating a specific transport packet from the input two or more transport streams through a corresponding filter; Processing the separated transport packet in a corresponding processor; And Generating one transport stream by reassembling and time division multiplexing the processed transport packet. The method of claim 13, wherein processing into one transport stream comprises: Storing the transport packets classified from the plurality of filters and passing the stored values to the corresponding processor. 14. The method of claim 13, wherein the step of separating the specific transport packet through the filter A first step of separating only a transport packet (a) containing information about a program included in a transport packet currently being transmitted from the input two or more transport streams; A second step of separating only the transport packet (b) from the inputted two or more transport streams containing information on which packet the video bit stream or audio bit stream is transmitted by; Separating a transport packet (c) containing video bit stream or audio bit stream information from the inputted two or more transport streams; A fourth step of separating only the transport packet (d) containing conditional reception information from the input two or more transport streams; Separating a transport packet (e) containing encrypted bit string information from the inputted two or more transport streams; And And a sixth step of separating only the transport packet (f) containing link information between the repeater and the program from the input two or more transport streams. The method of claim 13, wherein the processing in the processor A first step of recombining a transport packet (a) containing information on a program included in a transport packet currently transmitted from among transport packets separated by the plurality of filters; A second step of processing a transport packet (b) which contains information on which packet is transmitted by a video bit stream or an audio bit stream among transport packets separated by the plurality of filters; A third step of processing a transport packet (c) containing video bit stream or audio bit stream information among transport packets separated by the plurality of filters; A fourth step of processing a transport packet (d) containing conditional reception information among transport packets separated by the plurality of filters; A fifth step of processing a transport packet (e) containing encrypted bit string information among transport packets separated by the plurality of filters; And And a fifth step of processing the packet (f) containing link information between the repeater and the program among the transport packets separated by the plurality of filters. 17. The method of claim 16, wherein the transport packet (a) is a PAT and the first step is The program number PID and program map PID of the output PAT are arranged to rearrange the program number PID and the program map PID existing in the separated PATs so that there are no duplicate values. How to remultiplex a transport stream. 17. The method of claim 16, wherein the transport packet b is a PMT, and the second step is And re-writing "Elmentary PID" and "CA PID" of the output PMT so that there are no duplicate values. 17. The method of claim 16, wherein the transport packet (c) is PES, and the third step is And changing the PID in the header portion of the output PES to the " Elementary PID " value determined through the second step. The method of claim 16, wherein the transport packet (d) is CAT, and the fourth step is And re-writing the "CA PID" included in the "descriptor" of the output CAT so that there are no duplicate values. 17. The method of claim 16, wherein the transport packet e is a private section, and the fifth step is If the private section is an EMM, changing and describing a PID in a header portion of an output private section with a “CA PID” value determined through a processing by the CAT processor; And If the private section is an ECM transport stream, characterized in that the step of changing the PID in the header portion of the output private section to the "CA PID" value determined through the processing process by the PMT processor, characterized in that it comprises How to remultiplex. 17. The method of claim 16, wherein the transport packet (f) is NIT, and the sixth step is And changing and describing the PID in the output NIT header with a value of "network PID" determined through the first step.