JP5359929B2 - Transmission device, reception device, communication system, transmission method, and conversion method - Google Patents

Abstract

The disclosed transmission device-which generates a data signal by compressing a broadcast stream that has as configuring elements frames configured from broadcast packets comprising a header section, a data section, and an additional information section without being aware of the frame configuration of the broadcast stream and in a manner so that a reception device can replay the broadcast stream, and which transmits the data signal using a plurality of transmission packets-contains: a generating unit that, when a null packet, which is a type of broadcast packet, is present within the broadcast stream, compresses the broadcast stream-generating a data signal-by means of converting a section to be compressed, which is at least a part of the portion configured from the header section and the data section in the null packet, to a display information section that indicates the null packet and that has a smaller size than the size of the section to be compressed; and a transmission unit that transmits a data signal using a plurality of transmission packets.

Description

  The present invention relates to a transmission device, a reception device, a communication system, a transmission method, and a conversion method for transmitting a broadcast stream.

  A technique for transmitting a TS (Transport Stream) in a terrestrial digital broadcasting signal format to a predetermined transmitting station or relay station is known. A terrestrial digital broadcast signal format TS can generally be called a broadcast stream.

  As a TS of the signal format of terrestrial digital broadcasting, there is a broadcasting TS of ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) format. The broadcast TS is configured by a multiplexed frame in which a plurality of pieces of information (for example, audio information, video information, and data information) are multiplexed. In the ISDB-T format broadcast TS, a multiplex frame is generated by multiplexing a frame in which a plurality of pieces of information are multiplexed. The multiplex frame is composed of a plurality of broadcast TS packets.

  Patent Document 1 discloses a transmission system that converts an ISDB-T format broadcast TS into a satellite digital broadcast signal format and transmits the converted broadcast TS to a relay station via the broadcast satellite, and a converted version from the broadcast satellite. A relay station that receives a broadcast TS and converts the received broadcast TS into ISDB-T format is described.

  In addition, the transmission system described in Patent Document 1 deletes a null packet in an ISDB-T format broadcast TS in order to reduce the amount of transmission, and the broadcast TS from which the null packet is deleted is converted into a satellite digital signal. Convert to broadcast signal format and transmit the converted broadcast TS.

JP 2009-44354 A

  The transmission system described in Patent Literature 1 deletes a Null packet in a broadcast TS in ISDB-T format. When the null packet is deleted from the broadcast TS, the configuration of the multiplex frame having the deleted null packet is destroyed.

  Therefore, in the repeater described in Patent Document 1, for example, when a broadcast TS converted into a satellite digital broadcast signal format is converted into an ISDB-T format broadcast TS, a frame configuration pattern is regenerated and regenerated. There is a problem that it is necessary to reconstruct a multiplex frame based on the frame configuration pattern.

  The present invention provides a transmission device, a reception device, a communication system, a transmission method, and a conversion method that can solve the above-described problems.

  The transmitting apparatus of the present invention generates a data signal by compressing a broadcast stream including a frame composed of a broadcast packet including a header part, a data part, and an additional information part, and transmits the data signal to a plurality of transmissions. When a null packet which is a kind of the broadcast packet is present in the broadcast stream, the transmission device transmits using the packet, and at least one of the parts configured by the header portion and the data portion in the null packet Generating means for compressing the broadcast stream and generating the data signal by converting the compression target portion, which is a portion, into a display information portion having a size smaller than the size of the compression target portion and indicating the null packet And transmitting means for transmitting the data signal using the plurality of transmission packets.

  The receiving device of the present invention includes a receiving unit that receives a plurality of transmission packets transmitted from the transmitting device, an acquiring unit that acquires the data signal from a plurality of transmission packets received by the receiving unit, and the acquisition Change means for changing the data signal to a broadcast stream by changing the display information portion to the compression target portion when the display information portion is present in the data signal acquired by the means. .

  The communication system of the present invention includes the transmission device and the reception device.

  In the transmission method of the present invention, a data stream is generated by compressing a broadcast stream including a frame composed of a broadcast packet including a header part, a data part, and an additional information part, and the data signal is transmitted in a plurality of ways. A transmission method in a transmission apparatus that transmits using a packet, and when a null packet that is a kind of the broadcast packet exists in the broadcast stream, it is configured by a header portion and a data portion in the null packet By compressing the compression target portion that is at least a part of the portion into a display information portion having a size smaller than the size of the compression target portion and indicating the null packet, the broadcast stream is compressed to convert the data signal A generating step of generating, and a transmitting step of transmitting the data signal using the plurality of transmission packets.

  The conversion method of the present invention is a conversion method in a receiving apparatus, the receiving step for receiving a plurality of transmission packets transmitted from the transmitting apparatus, and the acquiring step for acquiring the data signal from the plurality of transmission packets; When the display information part is present in the data signal, the display information part is changed to the compression target part, thereby changing the data signal to a broadcast stream.

  According to the present invention, the amount of transmission can be reduced, and the receiving apparatus can reproduce the broadcast stream without reconfiguring the frame structure of the broadcast stream.

It is the figure which showed the broadcasting system of one Embodiment of this invention. It is the figure which showed the packet structure. FIG. 6 is a diagram showing a broadcast TS, a signal A, and a signal B that are processed by the transmission side TS converter 12. It is the figure which showed signal B ', signal A', and broadcasting TS which are processed by the receiving side TS converter 22.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of a broadcasting system using a satellite line according to an embodiment of the present invention. The broadcasting system includes a transmitting station system 1, a receiving station system 2, and a satellite device 3. A broadcast system can generally be referred to as a communication system. The transmission station system 1 can generally be called a transmission device. The receiving station system 2 can be generally called a receiving device.

  In FIG. 1A, the transmission station system 1 includes an ISDB-T MUX (multiplexer) device 11, a transmission-side TS converter 12, a satellite line transmitter 13, and a reference signal generator 14.

  The reference signal generator 14 is a GPS (Global Positioning System) synchronous reference signal generator. The reference signal generator 14 generates a 10 MHz reference signal synchronized with the GPS signal. The reference signal generator 14 outputs a 10 MHz reference signal to the ISDB-T MUX device 11.

  The ISDB-T MUX device 11 is a TS (Transport Stream) multiplexing device for digital terrestrial broadcasting. The ISDB-T MUX device 11 generates a clock synchronized with the 10 MHz reference signal output from the reference signal generator 14 and generates a 32.5 Mbps broadcast TS (packet size of 204 bytes) synchronized with the clock. Generate. A broadcast TS can generally be called a broadcast stream.

  Note that the broadcast TS generated by the ISDB-T MUX device 11 is a broadcast TS in the ISDB-T format. The ISDB-T format broadcast TS includes a multiplexed frame in which a plurality of pieces of information (for example, audio information, video information, and data information) are multiplexed. In the ISDB-T format broadcast TS, a multiplex frame is generated by multiplexing a frame in which a plurality of pieces of information are multiplexed. Multiple frames can generally be referred to as frames. The multiplex frame is composed of a plurality of broadcast TS packets. A broadcast TS packet can be generally called a broadcast packet.

  FIG. 2A is a diagram showing a configuration of the broadcast TS packet 4.

  In FIG. 2A, a broadcast TS packet 4 includes a TS header portion 41 indicating information such as a 0x47 value (hexadecimal display), a packet ID (PID), and a continuity counter value, an adaptation field, and a payload. (Hereinafter referred to as a “payload part”) 42 and a dummy byte part 43.

  The TS header portion 41 can be generally called a header portion. Payload portion 42 can be generally referred to as a data portion. Dummy byte portion 43 can generally be referred to as an additional information portion.

  The size of the TS header portion 41 is 4 bytes. The size of the payload part 42 is 184 bytes. The size of the dummy byte part 43 is 16 bytes. For this reason, the size of the broadcast TS packet 4 is 204 bytes.

  Control information defined by the ISDB-T method is described in the 8 bytes before the dummy byte portion 43. This control information is called ISDB-T Information (hereinafter referred to as “II”) and includes layer information indicating the layer of the broadcast TS packet 4.

  In the remaining 8 bytes of the dummy byte portion 43, error correction information defined by the ISDB-T method is described. As the error correction information, a Reed-Solomon (hereinafter referred to as “RS”) code is used. Hereinafter, the dummy byte part is also referred to as an II + RS part.

  The ISDB-T MUX device 11 illustrated in FIG. 1A outputs the broadcast TS to the transmission-side TS conversion device 12.

  Note that when there is no data to be placed on the payload section 42, the ISDB-T MUX device 11 uses a transmission bit rate adjustment packet called a null packet as a packet constituting the broadcast TS, that is, a broadcast packet, as a transmission side TS. Output to the converter 12.

  Null packets that make up a broadcast TS form part of a multiplex frame that is a component of the broadcast TS. Similarly to the broadcast TS packet 4, the Null packet constituting the broadcast TS also includes a TS header portion 41 having a size of 4 bytes, a payload portion 42 having a size of 184 bytes, an II + RS portion 43 having a size of 16 bytes, Consists of.

  When receiving the broadcast TS, the transmission-side TS converter 12 converts the broadcast TS into a transmission TS. A transmission TS can be generally referred to as a transmission stream. The transmission TS is composed of a plurality of transmission TS packets. A transmission TS packet can be generally referred to as a transmission packet.

  FIG. 2B is a diagram showing the configuration of the transmission TS packet 5.

  In FIG. 2B, a transmission TS packet 5 includes a transmission TS header portion 51 indicating a 0x47 value (hexadecimal display) and a Payload_unit_start_indicator value, an adaptation field, and a payload (hereinafter referred to as a “payload portion”). 52).

  The transmission TS header portion 51 can be generally called a header portion. Payload portion 52 can generally be referred to as a data portion.

  The size of the transmission TS header 51 is 4 bytes. The size of the payload part 52 is 184 bytes. For this reason, the size of the transmission TS packet 5 is 188 bytes.

  FIG. 1B is a block diagram showing the transmission side TS converter 12.

  In FIG. 1B, the transmission side TS converter 12 includes a broadcast TS synchronizer 121, a Null packet compressor 122, a transmission TS packetizer 123, and a speed conversion processor 124. Broadcast TS synchronization section 121 and null packet compression section 122 are included in generation section 12A. Generation unit 12A can be generally referred to as generation means. The transmission TS packetizing unit 123, the speed conversion processing unit 124, and the satellite line transmitter 13 are included in the transmission unit 12B. Transmitter 12B can generally be referred to as a transmission means.

  FIG. 3 is a diagram showing a broadcast TS, a signal A, and a signal B that are processed by the transmission-side TS converter 12.

  The generation unit 12A illustrated in FIG. 1B has a TS header part (4 bytes) 41 and a payload part (184 bytes) in a null packet when a null packet which is a kind of broadcast TS packet exists in the broadcast TS. ) 42 is converted into a head display byte (1 byte), thereby compressing the broadcast TS and generating a signal A which is a data signal. The generation unit 12A outputs the signal A to the transmission unit 12B.

  The head display byte indicates a 0xB8 value representing the head of the null packet.

  Further, the portion composed of the TS header portion 41 and the payload portion 42 in the Null packet that is a broadcast TS packet can be called a compression target portion. The compression target part is at least a part of a part constituted by the TS header part 41 and the payload part 42 in a Null packet that is a broadcast TS packet.

  The transmission unit 12B transmits the signal A using a plurality of transmission TS packets.

  The broadcast TS synchronization unit 121 detects synchronization of the broadcast TS. For example, the broadcast TS synchronization unit 121 detects the 0x47 value from the TS header unit 41 in the broadcast TS packet 4, generates a synchronization signal synchronized with the detection timing of the 0x47 value, and outputs the synchronization signal to the Null packet compression unit 122. To do.

  The null packet compressing unit 122 compresses the null packet in the broadcast TS (see FIG. 3A) to generate a signal A (see FIG. 3B).

  In the present embodiment, the Null packet compression unit 122 reads information described in the TS header portion 41 of the broadcast TS packet 4 at a timing synchronized with the synchronization signal from the broadcast TS synchronization unit 121.

  When the PID indicating the null packet is described in the TS header section 41, the null packet compression section 122 and the payload section in the packet including the TS header section 41 (that is, the null packet) 42 is deleted, and a signal A is generated by adding a head display byte to the remaining II + RS unit 43 of the null packet.

  Note that the head display byte can be generally called a display information portion indicating a null packet. The size of the first display byte is 1 byte. For this reason, the size (1 byte) of the head display byte is smaller than the total size (188 bytes) of the TS header part 41 of the null packet and the payload part 42 of the null packet.

  The Null packet compression unit 122 outputs the signal A to the transmission TS packetization unit 123.

  When receiving the signal A, the transmission TS packetizing unit 123 divides the signal A into units of 184 bytes from the head of the signal A, that is, the size of the payload part 52 of the transmission TS packet 5, and the payload of the transmission TS packet 5 A part 52 is generated.

  The transmission TS packetizing unit 123 generates a 188-byte transmission TS packet 5 by newly adding a 4-byte transmission TS header 51 to each of the payload parts 52 of the transmission TS packet 5, thereby generating a transmission TS packet. A signal B constituted by the packet 5 is generated (see FIG. 3C).

  The transmission TS packetizing unit 123 converts the TS header part (hereinafter referred to as “first TS header part”) 41 of the first broadcast TS packet 4 in the ISDB-T multiplex frame into the frame constituting the signal B. The first transmission TS packet (hereinafter referred to as “first transmission TS packet”) 5 is arranged at the head position of the payload portion 52.

  Further, the transmission TS packetizing unit 123 sets the Payload_unit_start_indicator value in the transmission TS header 51 in the head transmission TS packet 5 to “1”, and the head transmission TS packet is a boundary between multiple frames constituting the broadcast TS. It shows that.

  The transmission TS packetizing unit 123 outputs the signal B to the speed conversion processing unit 124.

  The speed conversion processing unit 124 generates a transmission TS by inserting a null packet into the signal B in order to convert the bit rate of the signal B into a bit rate for the transmission TS. The speed conversion processing unit 124 outputs the transmission TS to the satellite line transmitter 13.

  When receiving the transmission TS, the satellite line transmitter 13 transmits the transmission TS to the satellite device 3.

  Upon receiving the transmission TS, the satellite device 3 transmits the transmission TS to the receiving station system 2.

  The receiving station system 2 includes a satellite line receiver 21, a receiving-side TS converter 22, an ISDB-T transmission facility 23, and a reference signal generator 24.

  The reference signal generator 24 is a GPS synchronous reference signal generator. The reference signal generator 24 generates a 10 MHz reference signal synchronized with the GPS signal. The reference signal generator 24 outputs a 10 MHz reference signal to the reception-side TS converter 22.

  The satellite line receiver 21 can be generally referred to as receiving means. The satellite line receiver 21 receives the transmission TS from the satellite device 3. In other words, the satellite line receiver 21 receives a plurality of transmission TS packets 5 from the satellite device 3. When receiving the transmission TS, the satellite line receiver 21 outputs the transmission TS to the reception-side TS converter 22.

  The receiving-side TS converter 22 receives the transmission TS received from the satellite line receiver 21 and the 10 MHz reference signal output from the reference signal generator 24, and transmits the broadcast TS transmission clock synchronized with the 10 MHz reference signal. And restore the broadcast TS from the transmission TS.

  FIG. 1C is a block diagram showing the receiving side TS converter 22.

  In FIG. 1C, the receiving side TS converter 22 includes a transmission TS synchronization unit 221, a speed conversion processing unit 222, a transmission TS header removal unit 223, a head display byte search processing unit 224, and a broadcast TS packet. And a conversion unit 225. The transmission TS synchronization unit 221, the speed conversion processing unit 222, and the transmission TS header removal unit 223 can be referred to as an acquisition unit 22A. Acquisition unit 22A can be generally referred to as acquisition means. The head display byte search processing unit 224 and the broadcast TS packetizing unit 225 can be referred to as a changing unit 22B. Changing unit 22B can be generally referred to as changing means.

  FIG. 4 is a diagram showing a signal B ′, a signal A ′, and a broadcast TS processed by the receiving side TS converter 22.

  The acquisition unit 22A illustrated in FIG. 1C acquires a signal A from a plurality of transmission TS packets received by the satellite channel receiver 21, and outputs the acquired signal A as a signal A ′ to the change unit 22B. To do.

  When the head display byte is present in the signal A ′, the changing unit 22B changes the head display byte to the TS header part 41 and the payload part 42 of the Null packet that is the broadcast TS packet 4, thereby changing the signal A ′. Is changed to broadcasting TS.

  The transmission TS synchronization unit 221 detects the synchronization of the transmission TS. For example, the transmission TS synchronization unit 221 detects the 0x47 value from the transmission TS header 51 in the transmission TS input to the reception-side TS converter 22.

  The transmission TS synchronization unit 221 generates a synchronization signal synchronized with the detection timing of the 0x47 value, and outputs the synchronization signal to the speed conversion processing unit 222.

  The speed conversion processing unit 222 receives the transmission TS and the synchronization signal from the transmission TS synchronization unit 211. The speed conversion processing unit 222 reads information described in the transmission TS header 51 of the transmission TS packet 5 at a timing synchronized with the synchronization signal from the transmission TS synchronization unit 211.

  When the PID described in the transmission TS header 51 indicates a null packet, the speed conversion processing unit 222 transmits the transmission TS packet having the transmission TS header 51 in which the PID indicating the null packet is described, that is, the speed conversion. The Null packet inserted by the processing unit 124 when converting the transmission bit rate is deleted from the transmission TS to generate a signal B ′. The signal B ′ shows the same content as the signal B.

  The speed conversion processing unit 222 detects the 0x47 value from the transmission TS header unit 51 in the signal B ′, and generates synchronization information indicating the detection timing of the 0x47 value.

  The speed conversion processing unit 222 outputs the signal B ′ and the synchronization information to the transmission TS header removal unit 223.

  When receiving the signal B ′ and the synchronization information, the transmission TS header removal unit 223 reads the Payload_unit_start_indicator value from the transmission TS header unit 51 in the signal B ′ in synchronization with the timing indicated by the synchronization information, A transmission TS header portion (hereinafter referred to as “head transmission TS header portion”) 51 indicating Payload_unit_start_indicator value = “1” is detected.

  A head TS header portion is arranged immediately after the head transmission TS header portion 51.

  Therefore, the transmission TS header removal unit 223 uses the detection result of the head transmission TS header 51 to identify the head TS header immediately after the head transmission TS header 51.

  Thereafter, the transmission TS header removing unit 223 removes the transmission TS header 51 from the signal B ′ to generate a signal A ′.

  Further, the transmission TS header removal unit 223 generates specific information for specifying the position where the head TS header part is present in the signal A ′. As the specific information, for example, a signal synchronized with the signal A ′ in which “H” appears when the first TS header portion appears in the signal A ′ is used.

  The transmission TS header removal unit 223 outputs the signal A ′ and the specific information to the head display byte search processing unit 224 and the broadcast TS packetization unit 225. The broadcast TS packetizing unit 225 only needs to output the signal A ′, and the specific information may not be output to the broadcast TS packetizing unit 225.

  When the head display byte search processing unit 224 receives the signal A ′ and the specific information, the head TS header portion (the first broadcast of the ISDB-T multiplexed frame) whose position in the signal A ′ is specified by the specific information is received. The TS header part included in the TS packet) is detected from the signal A ′.

  When the head display byte search processing unit 224 detects the head TS header part, it generates head TS header part position information for specifying the position of the head TS header part in the signal A ′. The head display byte search processing unit 224 may use the specific information from the transmission TS header removal unit 223 as head TS header part position information.

  The head display byte search unit 224 detects the subsequent TS header part and the head display byte having a value of 0xB8 on the basis of the head TS header part, and the position where the TS header part exists in the signal A ′. TS header part position information for specifying the first display byte position information for specifying the position where the first display byte exists in the signal A ′.

  As the TS header portion position information, for example, a signal that becomes “H” when the TS header portion appears in the signal A ′ and is synchronized with the signal A ′ is used. As the head display byte position information, for example, a signal that becomes “H” when the head display byte appears in the signal A ′ and is synchronized with the signal A ′ is used.

  The head display byte search processing unit 224 outputs the head TS header part position information, the TS header part position information, and the head display byte position information to the broadcast TS packetization unit 225.

  The broadcast TS packetizing unit 225 uses the TS header part position information and the head display byte position information to check the synchronization state of the signal A ′ and the TS header part position information and the head display byte position information.

  When the signal A ′ is synchronized with the TS header part position information and the head display byte position information, the broadcast TS packetization unit 225 uses the head TS header part position information to start the multiplexed frame starting position of the multiplexed TS. Further, based on the head display byte position information, the Null packet existing in the broadcast TS from the ISDB-T MUX device 11 is reproduced to restore the 32.5 Mbps broadcast TS in 204 byte format.

  Therefore, a null packet, which is a broadcast TS packet composed of a total of 204 bytes, in which the TS header portion 41 is 4 bytes, the payload portion 42 is 184 bytes, and the dummy byte portion 43 is 16 bytes, is restored. As a result, a 204-byte format broadcast TS can be restored.

  The broadcast TS packetization unit 225 outputs the restored broadcast TS to the ISDB-T transmission facility 23.

  When receiving the broadcast TS, the ISDB-T transmission facility 23 converts the broadcast TS into an ISDB-T modulation wave and transmits a signal for digital terrestrial broadcasting.

  If the signal A ′ is not synchronized with the TS header part position information and the head display byte position information, the broadcast TS packetization unit 225 performs predetermined error processing.

  Next, the operation will be described.

  First, an operation in which the transmission side TS converter 12 converts a broadcast TS into a transmission TS will be described.

  The broadcast TS (see FIG. 3A) input to the transmission-side TS converter 12 is detected by the Null packet compressor 122 after the 0x47 value is detected from the TS header 41 by the broadcast TS synchronizer 121. The TS header part 41 (4 bytes) and the payload part 42 (184 bytes) of the Null packet are deleted.

  The Null packet compression unit 122 adds a head display byte (1 byte) to the remaining II + RS unit 43 (16 bytes), and generates a signal A shown in FIG. The Null packet compression unit 122 outputs the signal A to the transmission TS packetization unit 123.

  When the transmission TS packetizing unit 123 receives the signal A, the transmission TS packetizing unit 123 divides the signal A in units of 184 bytes from the head of the data to generate the payload portion 52 of the transmission TS packet. The transmission TS packetization unit 123 generates a transmission TS packet 5 of 188 bytes by newly adding a transmission TS header 51 (4 bytes) to each of the payload parts 52 of the transmission TS packet. A signal B (see FIG. 3C) composed of the packet 5 is generated.

  Further, the transmission TS packetizing unit 123 converts the first TS header part (TS header part of the first broadcast TS packet 4 in the ISDB-T multiplex frame) 41 into the first transmission TS packet (in the frame constituting the signal B). It is arranged at the head position of the payload portion 52 of the head transmission TS packet) 5.

  Subsequently, the transmission TS packetizing unit 123 sets the Payload_unit_start_indicator value in the transmission TS header 51 in the head transmission TS packet 5 to “1”, and the head transmission TS packet is at the boundary of the multiple frames constituting the broadcast TS. Indicates that there is.

  The transmission TS packetizing unit 123 outputs the signal B to the speed conversion processing unit 124.

  Upon receiving the signal B, the speed conversion processing unit 124 generates a transmission TS by inserting a null packet into the signal B in order to convert the bit rate of the signal B into a bit rate for the transmission TS.

  As a result, the 204-byte format broadcast TS can be converted into a form that can be transmitted on the transmission path for the 188-byte format transmission TS packet, and the transmission amount of 32.5 Mbps can be reduced.

  The transmission TS generated by the transmission side TS converter 12 is output to the satellite line transmitter 13 and transmitted from the satellite line transmitter 13 to the satellite apparatus 3. The satellite device 3 transmits the transmission TS to the satellite line receiver 21.

  Next, the operation in which the receiving side TS converter 22 restores the transmission TS to the broadcast TS will be described.

  The receiving side TS converter 22 accepts the transmission TS received by the satellite line receiver 21.

  The transmission TS synchronization unit 221 detects a 0x47 value from the transmission TS header 51 in the transmission TS input to the reception-side TS converter 22, and generates a synchronization signal synchronized with the detection timing of the 0x47 value. The transmission TS synchronization unit 221 outputs the synchronization signal to the speed conversion processing unit 222.

  When the speed conversion processing unit 222 receives the transmission TS input to the reception-side TS conversion device 22 and the synchronization signal from the transmission TS synchronization unit 221, the speed conversion processing unit 124 transmits the transmission bit rate from the transmission TS. The null packet inserted at the time of conversion is deleted, and a signal B ′ shown in FIG.

  When generating the signal B ′, the speed conversion processing unit 222 detects the 0x47 value from the transmission TS header unit 51 in the signal B ′, and generates synchronization information indicating the detection timing of the 0x47 value.

  The speed conversion processing unit 222 outputs the signal B ′ and the synchronization information to the transmission TS header removal unit 223.

  When receiving the signal B ′ and the synchronization information, the transmission TS header removal unit 223 reads the Payload_unit_start_indicator value from the transmission TS header unit 51 in the signal B ′ in synchronization with the timing indicated by the synchronization information, A transmission TS header part (first transmission TS header part) 51 indicating Payload_unit_start_indicator value = “1” is detected.

  When the transmission TS header removing unit 223 detects the leading transmission TS header 51, the transmission TS header removing unit 223 uses the detection result of the leading transmission TS header 51 to identify the leading TS header immediately after the leading transmission TS header 51. To do.

  Thereafter, the transmission TS header removal unit 223 removes the transmission TS header 51 from the signal B ′ to generate a signal A ′.

  When the transmission TS header removal unit 223 creates the signal A ′, the transmission TS header removal unit 223 generates specific information for specifying the position where the leading TS header portion exists in the signal A ′.

  When the transmission TS header removal unit 223 generates the specific information, the transmission TS header removal unit 223 outputs the signal A ′ and the specific information to the head display byte search processing unit 224 and the broadcast TS packetization unit 225.

  When the head display byte search processing unit 224 receives the signal A ′ and the specific information, the head TS header portion (the first broadcast of the ISDB-T multiplexed frame) whose position in the signal A ′ is specified by the specific information is received. The TS header part included in the TS packet) is detected from the signal A ′.

  When the head display byte search processing unit 224 detects the head TS header part, it generates head TS header part position information.

  Subsequently, the head display byte search unit 224 detects the TS header part after that and the head display byte having the value 0xB8 with reference to the head TS header part, and TS header part position information and head display byte position information. And generate

  The head display byte search processing unit 224 outputs the head TS header part position information, the TS header part position information, and the head display byte position information to the broadcast TS packetization unit 225.

  When receiving the signal A ′, the specific information, the head TS header part position information, the TS header part position information, and the head display byte position information, the broadcast TS packetization unit 225 receives the TS header part position information, the head display byte position information, and Is used to confirm the synchronization state of the signal A ′ with the TS header part position information and the head display byte position information.

  When the signal A ′ is synchronized with the TS header part position information and the head display byte position information, the broadcast TS packetization unit 225 uses the head TS header part position information to start the multiplexed frame starting position of the multiplexed TS. Further, based on the head display byte position information, the Null packet existing in the broadcast TS from the ISDB-T MUX device 11 is reproduced to restore the 32.5 Mbps broadcast TS in 204 byte format.

  In this embodiment, the broadcast TS packetization unit 225, when the TS header part is present at the head position of the signal A ′, sets the TS header part as the head position and the 204th byte from the TS header part as the last position. The signal is divided from the signal A ′, and the signal divided from the signal A ′ is handled as a broadcast TS packet.

  In addition, when the TS header part is present at the head position of the signal A ′ obtained by dividing the broadcast TS packet, the broadcast TS packetizing section 225 sets the TS header section as the head position and the 204th byte from the TS header section. The signal as the final position is divided from the signal A ′, and the signal divided from the signal A ′ is handled as a broadcast TS packet.

  Also, the broadcast TS packetization unit 225 deletes the head display byte when the head display byte is present at the head position of the signal A ′, and the TS header section 41 having the PID (packet ID) of the null packet and the payload section. 42 is added to the head portion of the signal A ′. The broadcast TS packetization unit 225 stores the II + RS unit 43 added to the rear part of the head display byte as it is, and stores 184 bytes of compressed invalid data in the payload part 42. The broadcast TS packetizing unit 225 converts a null packet including a TS header unit 41 having a PID of a null packet, a payload unit 42 in which invalid data is stored, and an II + RS unit 43 into a broadcast TS packet as a signal A. Split from '.

  Also, the broadcast TS packetization unit 225 deletes the head display byte when the head display byte exists at the head position of the signal A ′ obtained by dividing the broadcast TS packet, and the TS header unit 41 having the PID of the null packet. And the payload portion 42 are added to the head portion of the signal A ′. The broadcast TS packetization unit 225 stores the II + RS unit 43 added to the rear part of the head display byte as it is, and stores 184 bytes of compressed invalid data in the payload part 42. The broadcast TS packetizing unit 225 converts a null packet including a TS header unit 41 having a PID of a null packet, a payload unit 42 in which invalid data is stored, and an II + RS unit 43 into a broadcast TS packet as a signal A. Split from '.

  Therefore, the 204-byte broadcast TS is restored.

  Since the transmission clock for the broadcast TS restored by the broadcast TS packetization unit 225 is synchronized with the GPS signal in the same manner as the broadcast TS of the transmission station system 1, the ISDB-T MUX device 11 generates the transmission clock. Fully synchronized with the transmission clock.

  The position of each packet in the broadcast TS (ISDB-T multiplex frame) restored by the broadcast TS packetization unit 225 is also in the broadcast TS (ISDB-T multiplex frame) generated by the ISDB-T MUX device 11. Exactly matches the position of each packet in

  Therefore, the broadcast TS structure (ISDB-T multiple frame structure) restored by the broadcast TS packetization unit 225 is also the same as the broadcast TS structure (ISDB-T multiple frame structure) generated by the ISDB-T MUX device 11. Match exactly. Also, in the broadcast TS restored by the broadcast TS packetization unit 225 and the broadcast TS generated by the ISDB-T MUX device 11, the arrangement positions of the PCR packets are the same, and it is not necessary to correct the PCR values in the PCR packets.

  The broadcast TS restored by the reception-side TS converter 22 is input to the ISDB-T transmission facility 23.

  According to the present embodiment, in the transmission station system 1, when a Null packet that is a kind of the broadcast TS packet 4 is present in the broadcast TS, the generation unit 12 </ b> A has a TS header part 41 and a payload part 42 in the Null packet. That is, the broadcast TS is compressed by converting the compression target portion into the head display byte, and the signal A which is a data signal is generated. The transmission unit 12B transmits the signal A using a plurality of transmission TS packets 5.

  For this reason, the signal A existing in a compressed state of the Null packet in the broadcast TS is transmitted using a plurality of transmission TS packets. Therefore, it is possible to reduce the amount of transmission and compress the transmission band compared to the case where a broadcast TS that exists in a compressed state of Null packets in the broadcast TS is transmitted using a plurality of transmission TS packets. .

  Further, the number of packets and the arrangement of packets in the broadcast TS are also maintained by the signal A. For this reason, the structure of the multiplex frame constituted by the packets in the broadcast TS is also maintained by the signal A. In the present embodiment, in the receiving station system 2, the satellite line receiver 21 receives a plurality of transmission TS packets 5 transmitted from the transmitting station system 1. The acquiring unit 22A acquires the signal A from the plurality of transmission TS packets 5 received by the satellite line receiver 21, and outputs the signal A as the signal A '. When the head display byte is present in the signal A ′, the changing unit 22B changes the head display byte to the TS header part 41 and the payload part 42 of the Null packet that is the broadcast TS packet 4, thereby changing the signal A ′. Change to broadcast TS.

  As described above, the number of packets and the arrangement of packets in the broadcast TS are also maintained in the signal A. For this reason, the structure of the multiplex frame constituted by the packets in the broadcast TS is also maintained by the signal A. Therefore, if the receiving station system 2 restores the compressed Null packet present in the signal A, it is possible to reproduce the broadcast TS without considering the configuration of the multiplexed frame.

  Therefore, it is not necessary for the receiving station system 2 to regenerate the frame configuration pattern based on the transmission TS, and to reconstruct the multiplexed frame based on the regenerated frame configuration pattern.

  In addition, since the number of packets and the arrangement of packets in the broadcast TS are also maintained in the signal A, the multiplexed position of the PCR packet in the broadcast TS after playback is the same as the multiplexed position of the PCR packet in the original broadcast TS. Become. For this reason, the PCR correction circuit for correcting the information in the PCR packet in the transmitting station system 1 and the receiving station system 2 can be eliminated.

  In the above embodiment, the size of the transmission TS packet is 188 bytes. However, the size of the transmission TS packet can be changed as appropriate, and may be 204 bytes, for example.

  In the above embodiment, the broadcast TS for terrestrial digital broadcasting is used as the broadcast TS. However, the broadcast TS can be appropriately changed. For example, the broadcast TS for BS / CS digital broadcast is used as the broadcast TS. May be.

  In the above embodiment, the ISDB-T format broadcast TS is used as the terrestrial digital broadcast TS. However, the terrestrial digital broadcast TS can be appropriately changed.

  In addition, a retransmission system that retransmits the restored broadcast TS may be used instead of the receiving station system 2 of the above embodiment.

  In addition, when RS error correction is not required in the ISDB-T transmission facility 23 of the receiving station system 2, the Null packet compression unit 122 does not leave all dummy byte parts (16 bytes) when compressing Null packets. Only the ISDB-T_information part (8 bytes) of the dummy byte part may be left. In this case, it is possible to further reduce the transmission amount and further compress the transmission band.

  Further, in this embodiment, the top packet of the ISDB-T multiplex frame comes to the payload of the top packet in the frame in the transmission TS, but the top packet of the ISDB-T multiplex frame and the packet in the transmission TS The relationship with the first packet in the frame is not limited to the above.

  For example, in an arbitrary interval, the TS header part of the broadcast TS is arranged immediately after the transmission TS header part of the transmission TS, and the TS header part of the broadcast TS immediately follows the transmission TS header part. The Payload_unit_start_indicator value may be set to “1”.

  In this embodiment, the transmission TS is transmitted via the satellite device 3, but the transmission TS may be transmitted without passing the satellite device 3.

  In this embodiment, the transmission station system 1 has the ISDB-T NUX device 11 and the reference signal generator 14, but the transmission station system 1 has the ISDB-T NUX device 11 and the reference signal generator 14. Instead, the transmission-side TS converter 12 in the transmission station system 1 may accept a broadcast TS from the external ISDB-T NUX device 11.

  Further, in this embodiment, a part composed of the TS header part 41 and the payload part 42 in the Null packet which is a kind of broadcast TS packet is used as the compression target part. However, the compression target part can be changed as appropriate. is there. For example, only the TS header part 41 in the Null packet that is a kind of broadcast TS packet may be used as the compression target part, or the TS header part 41 and the payload in the Null packet that is a kind of broadcast TS packet. A part combined with a part of the part 42 may be used.

  The present embodiment can be used in a transmission system for terrestrial digital broadcasting TS or BS / CS digital broadcasting TS using various lines such as a satellite line and an FPU (Field Pickup Unit) line.

  In the embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

DESCRIPTION OF SYMBOLS 1 Transmission station system 11 ISDB-T MUX apparatus 12 Transmission side TS converter 12A Generation part 12B Transmission part 121 Broadcast TS synchronization part 122 Null packet compression part 123 Transmission TS packetization part 124 Speed conversion process part 13 Satellite line transmitter 14 Reference | standard Signal generator 2 Receiver station system 21 Satellite line receiver 22 Receiving side TS converter 22A Acquisition unit 22B Change unit 221 Transmission TS synchronization unit 222 Speed conversion processing unit 223 Transmission TS header removal unit 224 Lead display byte search processing unit 225 Broadcasting TS packetization part 23 ISDB-T transmission equipment 24 Reference signal generator 3 Satellite equipment

Claims (7)

Transmission that generates a data signal by compressing a broadcast stream including a frame composed of a broadcast packet including a header part, a data part, and an additional information part, and transmits the data signal using a plurality of transmission packets A device,
When a null packet that is a kind of the broadcast packet exists in the broadcast stream, a compression target portion that is at least a part of a portion composed of a header portion and a data portion in the null packet is changed to the compression target portion. Generating means for compressing the broadcast stream and generating the data signal by converting into a display information part having a size smaller than
Look including a transmitting means for transmitting the data signal using the plurality of transmission packets,
The transmission device is a transmission device , which is a portion configured by a header portion and a data portion in the null packet . The transmission apparatus according to claim 1 ,
In the additional information section, control information defined by the ISDB-T system and error correction information defined by the ISDB-T system are described,
When the null packet is present in the broadcast stream, the generation unit converts the compression target portion into the display information portion, and the error correction information is described in the additional information portion in the null packet. A transmission device that compresses the broadcast stream to generate the data signal by deleting the recorded portion. Receiving means for receiving a plurality of transmission packets transmitted from the transmitting apparatus according to claim 1 or 2,
Obtaining means for obtaining the data signal from a plurality of transmission packets received by the receiving means;
When the display information part is present in the data signal acquired by the acquisition means, changing means for changing the data signal to a broadcast stream by changing the display information part to the compression target part; Including a receiving device. Communication system including a transmitting apparatus according to claim 1 or 2, a receiving apparatus according to claim 3. Transmission that generates a data signal by compressing a broadcast stream including a frame composed of a broadcast packet including a header part, a data part, and an additional information part, and transmits the data signal using a plurality of transmission packets A transmission method in a device,
When a null packet that is a kind of the broadcast packet exists in the broadcast stream, a compression target portion that is at least a part of a portion composed of a header portion and a data portion in the null packet is changed to the compression target portion. Generating the data signal by compressing the broadcast stream by converting it into a display information part indicating a null packet having a size smaller than the size of
Look including a transmitting step of transmitting the data signal using the plurality of transmission packets,
The transmission target part is a transmission method , which is a part configured by a header part and a data part in the null packet . The transmission method according to claim 5 , wherein
In the additional information section, control information defined by the ISDB-T system and error correction information defined by the ISDB-T system are described,
In the generation step, when the null packet is present in the broadcast stream, the compression target part is converted into the display information part, and the error correction information is described in the additional information part in the null packet. The transmission method of generating the data signal by compressing the broadcast stream by deleting the processed part. A conversion method in a receiving device,
A receiving step of receiving a plurality of transmission packets transmitted from the transmitting apparatus according to claim 1 or 2,
Obtaining the data signal from the plurality of transmission packets;
When the display information part is present in the data signal, the conversion method includes changing the display information part to the compression target part to change the data signal to a broadcast stream.

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