KR20180071993A - System and method for stream failover switching in digital broadcasting system by PCR information - Google Patents

Abstract

The present invention relates to a system and a method for stream failover switching in a digital broadcasting system by utilizing PCR. The present invention proposes a method of using PCR of the MPEG-2 TS standard, capable of minimizing the influence of a broadcasting accident when an automatic switching to an emergency link is performed due to a problem of input signal caused by an accident of digital broadcasting equipment or transmission network in terrestrial DTV, IPTV, CATV, and satellite broadcasting. The present invention also provides a system and a method for stream failover switching in a digital broadcasting system by utilizing PCR, in which the broadcast output switching between a main input and a sub input is naturally performed at a broadcast accident and forcible transitions and errors of the ETSI TR 101 290 standard are minimized, thereby maintaining the quality of broadcasting upon a broadcasting accident. In the first embodiment, a PCR input synchronization method calculates a PCR value in ASI input 1 from an input receiver and an MPEG-2 TS of input 2 of a DTV RF tuner by tracking every packet and stores the corresponding packet in each buffer by an amount of a PCR difference between the input 1 (main input) and the input 2 (sub input). In order to prevent the transmission accident, the PCR input synchronization method 1 is used to perform a failover switching after buffering by the amount of packet difference between the ASI 0 and ASI 1 inputs. When a failover switching is performed from the main input to the sub input, a digital broadcasting signal is transmitted after an automatic failover switching by a switch under the control of an MPEG-2 TS PSI/PCR analyzer, a PCR synchronous control unit, and a buffer by using a method of shifting to the same PCR packet position of the main input as before Δt, so that packet loss and PCR delay are not generated.

Description

[0001] The present invention relates to a digital broadcasting system stream switching system and method using PCR,

The present invention relates to a digital broadcasting system stream switching system and method using a PCR (Program Clock Reference), and more particularly, to a digital broadcasting system stream switching system and method using a program clock reference In this paper, we propose a method using PCR of MPEG-2 TS standard as a method to minimize the influence of broadcasting accident in case of automatic transfer by emergency link. To a system and method for digital broadcasting system stream switching using PCR to maintain the quality of broadcasting in case of a broadcasting transmission accident by minimizing errors of the ETSI TR 101 290 standard.

In terrestrial, cable and satellite broadcasting systems, terrestrial digital broadcasting transmission uses ATSC 8-VSB, cable broadcasting uses QAM, and satellite broadcasting uses QPSK. The multiplexing method of terrestrial, cable, and satellite broadcasting systems uses MPEG-2 TS (Transport Stream).

I. Related Technology

1. MPEG-2 TS (Moving Picture Expert Group-2 Transport Stream)

MPEG-2 TS is a system protocol for audio, video and data transmission used for digital broadcast transmission. The transport stream (TS) provides an error correction function and is used for transmission of digital broadcasts such as DVB (Digital Video Broadcasting) and ATSC (Advanced Television Standard Committee). The transport stream (TS) supports packet header and program specific information (PSI). The receiving terminal can detect a TS packet error and analyze the configuration of the program through this information. The TS packet header and the PSI configuration information indicate the structure of the MPEG-2 TS packet as shown in FIG.

The MPEG-2 system creates a packetized elementary stream (PES) by packetizing each ES (Elementary Stream) created from the encoding of video and audio and stores the transport stream (TS) Lt; / RTI > The combination of these TS packets is TS.

i) ES (Elementary Stream)

Video -> Sampling -> DCT -> Quantizer / MC, ME -> Entropy Coding process is called ES. ES includes video ES, audio ES, and additional data ES. A broadcast schedule table such as EPG (Electro Program Guide) is used as typical additional data ES.

ii) PES (Packetized Elementary Stream)

ES is cut to a variable size that does not exceed 64 kbytes pure, and a packetized packet with a header added thereto is called a PES (Packetized Elementary Stream). As in the case of ES, video PES, audio PES, and additional data PES are independent since they are not yet multiplexed. These independent PESs are multiplexed to generate TS or PS.

iii) TS packet

The TS packet is composed of a 4-byte size header (TS Header) and a 184-byte payload (Play Data: real data area), each of which has a variable size PES. A packet stream in which a video PES, an audio PES, and an additional data PES are multiplexed is formed, and this combination of TS packets constitutes a transport stream (TS).

When an ES (Elementary Stream) is encoded, each ES is divided into E1, E2, E3 ... by data. PES Header is attached to this, and ES is converted into PES (Packetized Elementary Stream) data. To make this PES a TS, it is separated into a fixed size 4Byte header (TS Header) and a 184 byte payload (Playload) length, and the remaining portion is filled with NULL.

One PES is made into TS, and the remaining part is filled with NULL. If one PES is longer than the TS length, it is truncated to the TS length, and the last packet is filled with NULL.

Referring to FIG. 1, an MPEG-2 TS is configured with a 4-byte header and a 184-byte payload as basic units, and the broadcasting system constructs and transmits a transport stream of MPEG-2 TS successively.

The MPEG-2 TS packet header includes an 8-bit sync byte (0x47), a 1-bit transport error indicator (TEI), a 1-bit payload unit start indicator (PUSI) Transport Priority), a 13-bit PID (Porgram ID), a 2-bit Transport Scrambling Control (TSC), a 2-bit Adaptation Field Control, and a 4-bit Continuity counter.

2 is a block diagram of an MPEG-2 TS table & program.

Terrestrial, cable and satellite broadcasting signals are basically transmitted including video, audio, data and PSI (Program Specific Information). The broadcast system transmits channel information (SI) separately at the transmitting end. When there is a CAS, ECM and EMM are transmitted.

PSI is information representing the configuration of a program included in the MPEG-2 TS. The PSI classifies a plurality of programs, classifies video, audio, and data of the program, Lt; / RTI > The components of the PSI include Program Association Table (PAT), Program Map Table (PMT), Conditional Access Table (CAT), and Network Information Table (NIT). After analysis of PMT through PAT, Audio, Video and PCR (Program Clock Reference) PID (Program Identity) can be found through PMT.

2. SCR & PCR

In the MPEG-2 TS, the transmission unit transmits a time reference value relative to the program to the receiving unit. 3 and Equation (1) are equations for calculating the PCR position and the PCR value found. The PCR (Program Clock Reference) shows the system clock frequency (system_clock_frequency) and the time reference value for the program in the TS stream over time.

PCR (i) = PCR_base (i) * 300 + PCR_ext (i)

PCR_base (i) = ((system_clock_frequency * t (i)) / 300)% 2 ³³

PCR_ext (i) = ((system_clock_frequency * t (i)) 1)% 300 (1)

Here, "i" is the first MPEG-TS packet of the video intra frame, and PCR (i) is the receiver system time in the MPEG-TS packet.

PCR_base (i) is a value obtained by counting the carry of PCR_ext (i), and PCR_ext (i) is a value obtained by counting 300 with modulo at 27 MHz.

t (i) represents the i-th MPEG-TS packet transmission period according to the system clock frequency (system_clock_frequency).

The PCR / SCR consists of a 33-bit PCR_base expressed in units of 90 KHz (system_clock_frequency / 300) and a PCR_ext of 9 bits expressed in units of 27 MHz.

The PCR value is a value obtained by sampling the time at the system encoder at 27 MHz.

PCR is divided into a base 33-bit field and a 9-bit ext field for compatibility with MPEG-1. Also. It is composed of 48 (6byte) bits by placing six bits of meaningless bits in the middle for byte alignment. Since it is expressed in total 42 bits, the integer range of one unit is 0.0037 nsec, and the time range that can be expressed in PCR is 0.0037 nsec * (the maximum integer that can be expressed in 42 bits) = 162890.4 seconds. When the PCR value reaches the maximum value, it becomes 0 again.

Considering the delay in the transmission process from the broadcasting system to the receiving terminal, the absolute time indicated by the PCR in the encoder and the decoder is different.

However, since clock recovery is not based on absolute time but rather based on the PCR value generated by the encoder, the decoder loses the value written by the encoder as it is, and the delay time time is not considered.

3 is a diagram showing a PCR field (MPEG-2 TS) of an MPEG-2 TS.

The MPEG-2 TS is composed of a 4-byte header and a 184-byte payload as basic units, and the broadcasting system constructs and transmits a transport stream of MPEG-2 TS successively.

The MPEG-2 TS packet header includes an 8-bit sync byte (0x47), a 1-bit transport error indicator (TEI), a 1-bit payload unit start indicator (PUSI) Transport Priority), a 13-bit PID (Porgram ID), a 2-bit Transport Scrambling Control (TSC), a 2-bit Adaptation Field Control (AFC), a 4-bit Continuity Counter and an Adaptation Field.

The adaptation field consists of 8 bit Adaptation Field Length, 1 bit Discontinuity Indicator, 1 bit Random Access Indicator, 1 bit Stream Priority Indicator, 5 bit Flag Info, Conditional coding / option field and Stuffing byte.

Conditional coding / option field consists of PCR base, reserved, PCR extension, OPCR, Splice countdown, ....

In recent years, major digital broadcasting terrestrial broadcasting stations, multi-system operators (MSOs), and IPTV transmission companies have been making various efforts to prepare for accidents such as fail-over interruptions. When the broadcast transmission of one channel of the terrestrial wave, the cable, or the satellite broadcasting station is cut off, the TV receiver causes a screen stop phenomenon. In order to prevent the interruption of transmission due to the interruption of the input, a main switch and an auxiliary device are provided at the beginning of a transmission to transmit a broadcast on two channels to perform a failover switch.

These devices are installed at the beginning of the transmission to monitor the input and to switch the emergency signal when the input signal is interrupted or forced to Emergency Link. Most of the switching devices monitor and switch input signals at the beginning of broadcasting. Conventional devices use RF, ASI and IP input switching devices and use the input signal RF (Radio Frequency) signal strength, BER (Bit Error Rate) Or MPEG-2 (Moving Picture Expert Group) transport stream (TS) packet header to determine whether a signal loss, a packet error or a loss (packet error / loss) . Switching to an emergency link due to such physical switching or loss monitoring of MPEG-2 TS packets has a problem in that broadcast quality such as an asynchronization problem between main and negative input and a break of audio video is deteriorated.

Patent Registration No. 10-07475070000 (Date of Registration August 02, 2007), "Broadcasting System and Method", Korea Broadcasting Corporation Patent Registration No. 10-07214460000 (May 17, 2007) (Registration date May 17, 2007), "Broadcasting system and method, and broadcast receiving device", Korea Broadcasting Corporation

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a method and apparatus for preventing the influence of broadcast incidents when an automatic transmission is switched to an emergency link due to an input signal problem due to an accident of a digital broadcasting equipment or a transmission network during terrestrial DTV, IPTV, CATV, In this paper, we propose a method using PCR of MPEG-2 TS standard, minimize the error of ETSI TR 101 290, connect broadcast output switching between main input and broadcast input accidentally, And to provide a digital broadcasting system stream switching system and method using PCR to maintain quality of broadcasting.

In order to accomplish the object of the present invention, a digital broadcasting system stream switching system using PCR includes a DTV RF tuner having an antenna used as a main input, an ASI (Asynchronous Serial Interface) receiver used as a negative input, An input receiver for receiving 2-channel digital broadcast video, voice and data, and PSI information / or PSIP information from various inputs; The MPEG-2 TS PSI / PCR analyzer is provided in each of the two channels, and the digital broadcasting program is analyzed by an MPEG-2 TS PSI / PCR analyzer of each channel. MPEG-2 TS PSI / PCR analyzer to find PCR value; The PCR positions of the MPEG-2 TS of the main and sub input streams are synchronized and buffered through the PCR value found by the MPEG-2 TS PSI / PCR analyzer provided in each of the two channels including the main input channel and the negative input channel A PCR synchronization control unit and a buffer for transmitting a main input when there is no problem in the main input in the state where the PCR position of the MPEG-2 TS is synchronized and controlling the auxiliary input to be switched to the negative input when a trouble occurs in the main input; If the main input has no problem in the state where the PCR positions of the MPEG-2 TS are synchronized under the control of the PCR synchronization control unit and the buffer, the digital broadcasting signal of the main input is transmitted. If there is a problem in the main input, A switch for switching; And a DTV transmitter or an ASI transmitter for transmitting the digital broadcasting signal from a main input or a secondary input channel,

The above devices are provided at the beginning of the transmission, and the influence of the broadcasting accident when the automatic switching (failover switch) due to the trouble of the input signal due to the accident of the digital broadcasting equipment or the transmission network in the terrestrial DTV, IPTV, CATV, If the two input streams of the main input and the negative input are completely the same, the PCR input synchronization method 1 is used to buffer the packets as much as the packet difference between the ASI 0 and ASI 1 inputs. In case of broadcast incidents and forced switching, Switches the broadcast output of the input,

The PCR input synchronization method 1 stores a TS packet corresponding to Δt in the FPGA buffer of the PCR synchronization control unit and the buffer 15 when the input streams of the main input and the sub input are completely identical, The packet loss and the PCR delay do not occur in the output stream by outputting the output of the packet which is buffered in the ASI 1. In the case of the output of the terrestrial DTV tuner, the digital of the two channels (ASI 0, ASI 1) A broadcast signal is buffered only by the PCR difference, and when it is switched, it is detected and synchronized. When only the packet corresponding to? T is buffered, the packet is lost and a failover switch is performed without a PCR accuracy error.

In order to achieve the other object of the present invention, a digital broadcasting system stream switching method using PCR is provided with a DTV RF tuner, an ASI (Asynchronous Serial Interface) receiver or an IP (Internet Protocol) terminal used as a main input and a negative input Receiving digital broadcast video, voice and data, and PSI information and / or PSIP information from two or more channels from various inputs in an input receiver; The MPEG-2 TS PSI / PCR analyzer is provided in each of the two channels including the main input channel and the negative input channel. The MPEG-2 TS PSI / PCR analyzer analyzes the digital broadcast program of each channel, Finding a PCR value of the MPEG-2 TS after analyzing the information; The PCR positions of the MPEG-2 TS of the main and sub input streams are synchronized and buffered through the PCR value found by the MPEG-2 TS PSI / PCR analyzer provided in each of the two channels including the main input channel and the negative input channel A step of transmitting a main input when there is no problem in the main input by the PCR synchronization control unit and the buffer in a state in which the PCR position of the MPEG-2 TS is synchronized, and controlling the main input to switch to the negative input if a problem occurs; If there is no problem with the main input while the PCR position of the MPEG-2 TS is synchronized under the control of the PCR synchronization control unit and the buffer, the digital broadcasting signal of the main input is transmitted. If a problem occurs in the main input, To perform a failover switch; And transmitting the digital broadcasting signal from a primary input or a secondary input channel through a DTV transmitter or an ASI transmitter, and transmitting the digital broadcasting signal to a terrestrial DTV, IPTV, CATV, When the input stream of the two channels of the main input and the sub input is completely the same when the automatic switching to the emergency link due to the problem of the input signal, the PCR input synchronization method 1 is used to buffer the packet difference as much as the packet difference between the ASI 0 and ASI 1 inputs The broadcast output of the main and auxiliary inputs is switched when a broadcast accident or a forced switch is made,

In the PCR input synchronization method 1, when the input stream of the main input and the sub input are completely identical, a TS packet corresponding to? T is stored in the FPGA buffer of the PCR synchronization control unit and the buffer, and the switching is performed from ASI 0 to ASI 1 (ASI 0, ASI 1) in the case of the output of the terrestrial DTV tuner so that the packet loss and the PCR delay of the output stream do not occur by outputting the output of the buffered packet in the ASI 1. The PCR is buffered only for the difference, and the packet is synchronized when it is switched. When the packet corresponding to? T is buffered, the packet is lost and the packet is switched without a PCR accuracy error.

Major digital broadcast terrestrial broadcasters, Multi-System Operators (MSOs), and IPTV transmitters are making various efforts to prepare for accidents such as outage. In order to prevent interruption of transmission due to interruption of input, main switch and auxiliary device are connected at the beginning of transmission to perform failover switch.

The digital broadcasting system stream switching system and method using the PCR of the present invention automatically switches to an emergency link in the event of a problem of a transmission signal due to an accident of a digital broadcasting equipment or a transmission network in DTV, IPTV, CATV, and satellite broadcasting we propose a method that minimizes the impact on the failover switch broadcast quality. The digital broadcasting is transmitted according to the MPEG-2 TS standard. The primary input and the secondary input stream are switched by referring to the SCR (System Clock Reference) and the PCR (Program Clock Reference) in the MPEG-2 TS. The ETSI (European Telecommunication Standard Institute) TR 101 290 It is proposed to minimize the error of the digital broadcasting quality standard and to maintain the quality of broadcasting in the event of a failure. In addition, in the method proposed in the present invention, the digital broadcasting transmission stream It was possible to minimize PCR and packet errors according to the ETSI TR 101 290 standard.

When the broadcast transmission of one channel of the terrestrial wave, the cable, or the satellite broadcasting station is cut off, the TV receiver causes a screen stop phenomenon. In order to prevent the interruption of transmission due to the interruption of the input, a main switch and an auxiliary device are provided at the beginning of a transmission to transmit a broadcast on two channels to perform a failover switch.

These devices are installed at the beginning of the transmission to monitor the input and to switch the emergency signal or the Emergency Link when the input signal is interrupted.

In the first embodiment, the PCR input synchronization method calculates the PCR value in the MPEG-2 TS of the ASI input 1 and the input 2 of the DTV RF tuner from the input receiver every packet to calculate the input 1 (main input) and the input 2 2). The MPEG-2 TS PSI / PCR analyzer, the PCR synchronous controller, and the buffer are connected to each other by using a method of storing the corresponding packets in the respective buffers by the PCR difference of the input PCR And the digital broadcast signal is transmitted through a switch by a switch according to the control of the switch, thereby preventing packet loss and PCR delay of the output stream.

1 is a diagram showing a structure of an MPEG-2 TS packet.
2 is an MPEG-2 TS table & program structure diagram (MPEG-2 TS table & program structure).
3 is a diagram showing a PCR field (MPEG-2 TS) of an MPEG-2 TS.
4 is a block diagram of a digital broadcasting system stream switching system using PCR according to the present invention.
5 is a packet flow diagram of PCR input synchronization method 1: ASI 0, 1 according to the first embodiment of the present invention.
6 is a real-time flow chart of PCR input synchronization method 2: ASI 0, 1 according to a second embodiment of the present invention.
7 shows a photograph of a system board implemented in the present invention.
FIG. 8 is a screen showing the result of PCR non-synchronization during PCR asynchronization.
9 is a view showing a result of PCR input synchronization method 1 (Result of PCR Synchronization method 1).
10 is a view showing a result of the PCR input synchronization method 2 (Result of PCR Synchronization method 2).

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

The digital broadcasting system stream switching method using the PCR of the present invention proposes a method of automatically switching to an emergency link and minimizing the influence on broadcast quality when a problem of a transmission signal occurs due to an accident of a digital broadcasting equipment or a transmission network . Digital broadcasting is transmitted in conformity with the MPEG-2 TS standard, and refers to SCR (System Clock Reference) and PCR (Program Clock Reference) in a TS (Transport Stream) And proposes a method of maintaining the quality of broadcasting in the event of a failure by minimizing the error of the European Telecommunication Standard Institute (ETSI) TR 101 290 digital broadcast quality standard. In addition, according to the method proposed by the present invention, - When the input is forcibly switched (failover switch), the digital broadcast transmission stream can minimize PCR and packet error according to ETSI TR 101 290 specification.

4 is a block diagram of a digital broadcasting system stream switching system using PCR according to the present invention.

The digital broadcasting system stream switching system using the PCR of the present invention includes a DTV RF tuner 11 having an antenna used as a main input, an ASI (Asynchronous Serial Interface) receiver 12 used as a negative input, An input receiver 10 for receiving 2-channel digital broadcast video, audio and data, and PSI information (or PSIP information) from various inputs of the terminal;

An MPEG-2 TS PSI / PCR analyzer is provided in two channels connected to the DTV RF tuner 11 and the ASI receiver 12, respectively, and MPEG-2 TS PSI / An MPEG-2 TS PSI / PCR analyzer (13, 14) for analyzing program information of two inputs and analyzing the PCR value of MPEG-2 TS;

2 TS of the input stream between the primary and the secondary input through the PCR value found by the MPEG-2 TS PSI / PCR analyzer (13, 14) provided in each of the two channels including the primary input channel and the secondary input channel A PCR synchronization control unit for buffering synchronization of the PCR positions and transmitting the main input when there is no problem in the main input while the PCR position of the MPEG-2 TS is synchronized, (15);

If there is no problem with the main input in the state where the TS PCR position of MPEG-2 is synchronized under the control of the PCR synchronization control unit and the buffer 15, the digital broadcasting signal of the main input is transmitted. If there is a problem in the main input, A switch 16 for performing a failover switch; And

A DTV transmitter or an ASI transmitter 17 for transmitting the digital broadcasting signal from a main input channel or a sub input channel,

These equipments are provided at the beginning of the transmission, and the influence of the broadcast accident when the automatic switch (failover switch) to the emergency link due to the problem of the input signal due to the accident of the digital broadcasting equipment or the transmission network in the terrestrial DTV, IPTV, CATV, If the two input streams of the main input and the negative input are completely identical to each other, the PCR is synchronized by using the PCR synchronization method 1 to buffer the packets as much as the packet difference between the ASI 0 and ASI 1 inputs. And the broadcast output of the broadcast program is switched.

The digital broadcasting signal from the main input channel or the secondary input channel includes digital broadcasting video / audio / data / PSI in the terrestrial or satellite broadcasting.

Also, the digital broadcast signal from the main input or the secondary input channel includes digital broadcast video / audio / data / PSIP at the time of cable broadcasting.

The PCR input synchronization method in the MPEG-2 TS is applied to the MPEG-2 TS PSI / PCR analyzers 13 and 14, the PCR synchronization control unit and the buffer 15.

The digital broadcasting system stream switching system using the PCR according to the present invention can be applied to digital broadcasting video / audio / data / PSI information (or PSIP information) from various inputs such as an RF tuner, ASI (Asynchronous Serial Interface) Analyzes the program information of the two inputs, analyzes the digital broadcast program, and finds the PCR value of the MPEG-2 TS. The PCR positions of the MPEG-2 TS of the main and sub input streams are determined through the PCR values found by the MPEG-2 TS PSI / PCR analyzers (13, 14) provided in the two channels including the main input channel and the secondary input channel, Synchronize. If the main input has no problem in the state where the PCR position of the MPEG-2 TS is synchronized, a broadcast signal of the main input is transmitted. If a problem occurs in the main input, have.

The digital broadcasting system stream switching system using the PCR according to the first embodiment is a system in which terrestrial DTV, IPTV, CATV, satellite broadcast, In order to minimize the influence of broadcast incidents during the switch, the PCR method of MPEG-2 TS standard is used. It is provided at the beginning of the transmission and connects the broadcast output switching between the main input and the negative input naturally, The error of the TR 101 290 standard is minimized, and the quality of the broadcast is maintained in the event of a broadcast transmission accident.

In the PCR input synchronization method 1 according to the first embodiment, the PCR value in the MPEG-2 TS of the ASI input 1 and the input 2 of the DTV RF tuner is calculated for each packet and input 1 (main input) and input 2 ) In the respective buffers, and moves to the same PCR packet position at the time of the failover switch.

In the PCR input synchronization method 1, the PCR value in the MPEG-2 TS of the ASI input 1 of 2 channels and the input 2 of the DTV RF tuner is computed every packet from the input receiver 10 and input 1 (main input) 2 (negative input), the packets are stored in the respective buffers. In order to prevent a transmission accident, the PCR input synchronization method 1 is used for the failover switch to buffer the packet difference between the ASI 0 and ASI 1 inputs 2 TS PSI / PCR analyzer (13, 14) and PCR (12) using a method of moving to the same PCR packet position before △ t of the main input upon failover switch from main input to negative input And is automatically switched by the switch 16 in accordance with the control of the synchronization control unit and the buffer 15 to transmit the digital broadcast signal through the DTV transmitter or the ASI transmitter 17. [

These devices usually have two channels and are installed at the beginning of the transmission to monitor the input and to switch the emergency signal when the input signal is interrupted or forced to Emergency Link.

When the broadcast transmission of one channel of the terrestrial wave, the cable, or the satellite broadcasting station is cut off, the TV receiver causes a screen stop phenomenon. In order to prevent the interruption of transmission due to the interruption of the input, it is possible to use the main device and the auxiliary device at the beginning of the transmission to transmit the broadcast on the two channels and to use it for the failover switch.

The present invention provides two PCR input synchronization methods.

(Example 1)

1. PCR Input Synchronization Method 1: When the PCR values of ASI0 input and ASI1 input are completely equal

5 is a packet flow diagram of PCR input synchronization method 1: ASI 0, 1 according to the first embodiment of the present invention.

PCR Input Synchronization Method 1, when the input stream of two channels of the main input and the sub input is completely the same, TS packets corresponding to Δt are stored in the respective FPGA buffers, and when the switching from ASI 0 to ASI 1 is performed, ASI 1 And the output of the digital broadcast signal is transmitted to prevent the packet loss and the PCR delay of the output stream from occurring.

In this case, it is the output of the terrestrial DTV tuner (terrestrial DTV tuner). The digital broadcasting signals of the two channels (ASI 0, ASI 1) are buffered only by the PCR difference, If only packets corresponding to? T in FIG. 5 are buffered, a packet loss and a failover switch can be performed without a PCR accuracy error.

(Example 2)

2. PCR Input Synchronization Method 2: If the PCR values of ASI0 input and ASI1 input are not completely the same

6 is a real-time flow chart of PCR input synchronization method 2: ASI 0, 1 according to a second embodiment of the present invention.

PCR input synchronization method 2 is a case in which the two channel ASI 0 and ASI 1 input streams are not completely identical. In this case, TS packets corresponding to t are stored in the FPGA buffer, and when switching from ASI 0 to ASI 1 is performed, the buffered packet position is found in ASI 1 and the output is transmitted. However, since a null packet is inserted in the middle, the PCR value of the PCR packet becomes completely unequal. The reason for this is that the PCR value may be different due to PCR re-stamping and null packet insertion in order to adjust the data rate while passing through the ASI interface. In this case, the PCR value difference between ASI 0 and 1 input is tracked in units of packets and buffered by the maximum PCR difference value to synchronize the input between main and side. However, due to the limitation of the buffer capacity of the system, the present invention is limited to two times of 312 packets.

II. System design and implementation

7 shows a photograph of a system board implemented in the present invention.

III. Experiment result

In the embodiment, the reception analysis equipment was analyzed by the receiver according to the ETSI TR101 290 standard using DEKTEC's DTU-234 equipment and StreamExpert software.

1. Experimental results of PCR asynchronization

In case of PCR asynchronization of the input stream, since PCR monitoring and buffering between ASI 0 input and ASI 1 input are not performed, the PCR and packet order between ASI 0 and 1 input may be overlapped or lost. The results of the experiment are shown in Fig.

FIG. 8 is a screen showing the result of PCR non-synchronization during PCR asynchronization.

TR101 290 Monitoring result Continuity count error, PCR discontinuity, PCR accuracy error occurred and TS packet continuity count error was high. In this case, loss of video or audio packets occurs.

2. PCR input synchronization method 1 Experimental result

In the case of the PCR input synchronization method 1 (embodiment 1), processing can be performed without packet loss of broadcasting because buffering is performed by a packet difference between ASI 0 and ASI 1 input, and the experimental result is shown in FIG. In the case of the PCR input synchronization method 1 (embodiment 1), since there is no difference in input, it can be seen that the automatic switching is performed very well.

In addition, it showed that it works well without error at all according to ETSI TR101 290 standard.

9 is a view showing a result of PCR input synchronization method 1 (Result of PCR Synchronization method 1).

3. PCR Input Synchronization Method 2 Experimental Results

In the case of the PCR synchronization method 2 (embodiment 2), the packet was shifted by a packet difference between ASI 0 and ASI 1 inputs, and the position of the packet was changed due to an incorrect position difference of the PCR packet, but the position of the image was not significantly different .

In the case of method 2, the type of error in switching between main parts is within the range of 0 to 11 μsec within 1 sec or 2 packet loss and PCR Accuracy Error of TS packet Continuity Count Error. Other audio-video packet losses occurred, mostly within audio 1-frame (24.2msec at 48KHz sampling) or video 1-slice (16.6msec at 60Hz). The results of this experiment are shown in FIG.

10 is a view showing a result of the PCR input synchronization method 2 (Result of PCR Synchronization method 2).

The present invention claims the patent right for the first embodiment.

The digital broadcasting system stream switching method using the PCR according to the first embodiment

A DTV RF tuner 11 used as a main input and a negative input and an input receiver 10 having an ASI (Asynchronous Serial Interface) receiver 12 or an IP And receiving and receiving voice, data, and PSI information (or PSIP information);

Each of the two channels is provided with an MPEG-2 TS PSI / PCR analyzer. The MPEG-2 TS PSI / PCR analyzer 13 or 14 analyzes the digital broadcasting program and analyzes the program information of the two inputs Finding a PCR value of the MPEG-2 TS;

The MPEG-2 TS PCR positions of the primary and secondary input streams are determined through the PCR value found by the MPEG-2 TS PSI / PCR analyzer (13, 14) provided in each of the two channels including the primary input channel and the secondary input channel When the main input is not affected by the PCR synchronization control unit and the buffer 15 while the PCR position of the MPEG-2 TS is synchronized, a broadcast signal of the main input is transmitted. If there is a problem in the main input, ;

If there is no problem with the main input in the state where the PCR position of the MPEG-2 TS is synchronized under the control of the PCR synchronization control unit and the buffer 15, the digital broadcasting signal of the main input (input 1) is transmitted, Switching to a negative input (input 2) using a live switch 16 to perform a failover switch; And

Transmitting the digital broadcast signal from a primary input or a secondary input channel through a DTV transmitter or an ASI transmitter 17,

In the case of terrestrial DTV, IPTV, CATV, satellite broadcasting, the input channel of two channels of main input and negative input during emergency switch (failover switch) Is completely the same, the PCR input synchronization method 1 is used to buffer and transfer the packet difference between the ASI 0 and ASI 1 inputs, and to switch the broadcast output of the main input and the negative input during a broadcast accident and forced switchover.

The digital broadcasting signal from the primary input or the secondary input channel includes digital broadcast video / audio / data / PSI in the terrestrial or satellite broadcasting.

The digital broadcast signal from the primary input or the secondary input channel includes digital broadcast video / audio / data / PSIP at the time of cable broadcasting.

The PCR input synchronization method 1 calculates the PCR values in the MPEG-2 TS of the ASI input 1 and the input 2 of the DTV RF tuner from the input receiver 10 and calculates input values 1 (main input) and 2 The packet is stored in the respective buffers by the PCR difference of the main input and the negative input, and in case of failover switch from the main input to the sub input in order to prevent a transmission accident, 2 TS PSI / PCR analyzers 13 and 14 provided in two channels including a primary input channel and a secondary input channel, respectively, and the PCR (synchronous control) 16 to automatically transmit the digital broadcast signal.

As a result, if the PCR values of the two inputs are exactly the same as the PCR input synchronization method 1 (Example 1) proposed in the present invention, the ASI 0,1 input can be accurately transferred. If the TS packet is correctly transferred, it can hardly be sensed that the receiver has received the digital broadcast signal.

In addition, even when the PCR input synchronization method 2 (Example 2) proposed in the present invention is used, even when the ASI 0,1 input PCR value deviates, the transfer is performed at a relatively accurate point. In this case as well, there is a continuity count error, a PCR discontinuity, a PCR accuracy error, a PAT PMT error and other types of errors and the number of error packets decreased from 5 packets to 1 packet. Decreasing the error of the packet does not need to initialize the MPEG-2 TS decoder in the receiver. Therefore, it is possible to reduce the frequency of occurrence of video break, audio mute or Tick Noise and hold time in the receiver .

As described above, the digital broadcasting system stream switching method using the PCR of the present invention can be implemented by a program and can be recorded on a recording medium (CD-ROM, RAM, ROM, memory card, hard disk, Magneto-optical disks, storage devices, etc.).

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that various modifications and changes may be made without departing from the scope of the present invention.

10: Input Receiver 11: DTV RF Tuner
12: ASI receiver 13,14: MPEG-2 TS PSI / PCR analyzer
15: PCR synchronization control unit and buffer 16: switch
17: DTV transmitter or ASI transmitter

Claims (8)

A digital broadcasting system stream switching system comprising:
Channel DTV image, voice and data, and PSI information or PSIP information from various inputs of an Asynchronous Serial Interface (ASI) receiver or an IP terminal used as a negative input, a DTV RF tuner having an antenna used as a main input, An input receiver for receiving;
The MPEG-2 TS PSI / PCR analyzer is provided in each of the two channels, and the digital broadcasting program is analyzed by an MPEG-2 TS PSI / PCR analyzer of each channel. MPEG-2 TS PSI / PCR analyzer to find PCR value;
The MPEG-2 TS PCR positions of the main and sub input streams are synchronized and buffered through the PCR value found by the MPEG-2 TS PSI / PCR analyzer provided in each of the two channels including the primary input channel and the secondary input channel, A PCR synchronization control unit and a buffer for transmitting a broadcast signal of the main input when there is no problem in the main input in the state where the MPEG-2 TS PCR position is synchronized and controlling the input to be negative when a trouble occurs in the main input;
If there is no problem with the main input while the MPEG-2 TS PCR position is synchronized according to the control of the PCR synchronization control unit and the buffer, the digital broadcasting signal of the main input is transmitted. If a problem occurs in the main input, Switches; And
A DTV transmitter or an ASI transmitter for transmitting the digital broadcasting signal from a main input or a secondary input channel,
The above devices are provided at the beginning of the transmission, and when a failover switch is performed in an emergency link due to an input signal problem due to an accident of a digital broadcasting equipment or a transmission network in terrestrial DTV, IPTV, CATV, Channel input stream is completely the same, the PCR input synchronization method 1 is used to buffer and transfer the packet difference between the ASI 0 and ASI 1 inputs, switch the broadcast output of the main input and the negative input at the time of broadcast incidents and forced switching,
The PCR input synchronization method 1 stores a TS packet corresponding to Δt in the FPGA buffer of the PCR synchronization control unit and the buffer 15 when the input streams of the main input and the sub input are completely identical, The packet loss and the PCR delay do not occur in the output stream by outputting the output of the packet which is buffered in the ASI 1. In the case of the output of the terrestrial DTV tuner, the digital of the two channels (ASI 0, ASI 1) A digital broadcasting system stream switching system using PCR, which is buffered only by the PCR difference, finds and synchronizes with the PCR, and buffers only the packet corresponding to Δt, thereby failing to switch the packet without loss of PCR and PCR accuracy. . The method according to claim 1,
Wherein the digital broadcasting signal from the primary input or the secondary input channel includes a digital broadcast video / audio / data / PSI during terrestrial or satellite broadcasting. The method according to claim 1,
Wherein the digital broadcasting signal from the main input or the secondary input channel includes digital broadcasting video / audio / data / PSIP at the time of cable broadcasting. The method according to claim 1,
The PCR input synchronization method 1 calculates the PCR values in the MPEG-2 TS of the ASI input 1 and the input 2 of the DTV RF tuner from the input receiver 10 and calculates input values 1 (main input) and 2 The packet is stored in the respective buffers by the PCR difference of the main input and the negative input, and in case of failover switch from the main input to the sub input in order to prevent a transmission accident, 2 TS PSI / PCR analyzer provided in each of two channels including a primary input channel and a secondary input channel, and a PCR control unit and a buffer, A digital broadcasting system stream switching system using PCR. A digital broadcasting system stream switching method using PCR,
A DTV RF tuner used as a main input and a negative input, an input receiver having an ASI (Asynchronous Serial Interface) receiver or an IP (Internet Protocol) terminal, two channels of digital broadcast video, voice and data and PSI information / Receiving and receiving PSIP information;
The MPEG-2 TS PSI / PCR analyzer is provided in each of the two channels, and the digital broadcasting program is analyzed by an MPEG-2 TS PSI / PCR analyzer of each channel. Finding a PCR value;
The PCR positions of the MPEG-2 TS of the input stream between the main and the sub input are synchronized through the PCR value found by the MPEG-2 TS PSI / PCR analyzer provided in each of the two channels including the main input channel and the negative input channel If the main input is not affected by the PCR synchronization control unit and the buffer in the state where the PCR position of the MPEG-2 TS is synchronized, the digital broadcasting signal of the main input is transmitted. If a problem occurs in the main input, ;
If the main input has no problem in the state where the PCR position of the MPEG-2 TS is synchronized according to the control of the PCR synchronization control unit and the buffer, a broadcast signal of the main input is transmitted. If a problem occurs in the main input, Switching over to perform a failover switch; And
Transmitting the digital broadcast signal from a primary input or a secondary input channel through a DTV transmitter or an ASI transmitter,
In the case of terrestrial DTV, IPTV, CATV, satellite broadcasting, the input stream of two channels of main input and sub input is completely the same when automatic switching to emergency link due to the problem of input signal due to accident of digital broadcasting equipment or transmission network at the beginning of transmission The PCR input synchronization method 1 is used to buffer and switch the packet difference between the ASI 0 and ASI 1 inputs, to switch the broadcast output of the primary and secondary inputs in case of broadcast incidents and forced switching,
In the PCR input synchronization method 1, when the input stream of the main input and the sub input are completely identical, a TS packet corresponding to? T is stored in the FPGA buffer of the PCR synchronization control unit and the buffer, and the switching is performed from ASI 0 to ASI 1 (ASI 0, ASI 1) in the case of the output of the terrestrial DTV tuner so as to prevent the packet loss and the PCR delay of the output stream by outputting the output of the buffered packet in the ASI 1. A method of buffering only the PCR difference, detecting and synchronizing when the change is made, and buffering only packets corresponding to Δt, thereby failing to switch packets without packet loss and PCR accuracy error. 6. The method of claim 5,
Wherein the digital broadcasting signal from the main input or the secondary input channel includes digital broadcasting video / audio / data / PSI during terrestrial or satellite broadcasting. 6. The method of claim 5,
Wherein the digital broadcasting signal from the main input or the secondary input channel includes digital broadcasting video / audio / data / PSIP at the time of cable broadcasting. 6. The method of claim 5,
The PCR input synchronization method 1 calculates the PCR value in the MPEG-2 TS of the ASI input 1 and the input 2 of the DTV RF tuner from the input receiver and calculates input values of 1 (main input) and 2 (input) The packet is stored in the respective buffers as much as the PCR difference of the main input and the method of moving to the same PCR packet position before △ t of the main input in the case of failover switch from the main input to the sub input in order to prevent the transmission accident Wherein the MPEG-2 TS PSI / PCR analyzer, the PCR synchronization controller, and the buffer control the transmission of the digital broadcasting signal by the switch.

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