JP2023079391A - Broadcast signal conversion device and program therefor - Google Patents

Abstract

To provide a broadcast signal conversion device capable of preventing the MTU size from being exceeded and suppressing reduction in transmission efficiency.SOLUTION: A broadcast signal conversion device 1 includes: a video encoding unit 10 that encodes a video signal; an audio encoding unit 20 that encodes an audio signal; a control information generating unit 30 that fragments the leading fragment of control information to become a payload not exceeding a full header target fragment size, and fragments the remaining control information to become a payload not exceeding a basic fragment size; a multiplexing processing unit 40 that generates a multiplexed signal of IP packets storing the fragmented control information and the payloads of the video signal and the audio signal; and a TLV conversion unit 50 that converts the multiplexed signal of IP packets into TLV packets.SELECTED DRAWING: Figure 1

Description

The present invention relates to a broadcast signal converter and its program.

In IP (Internet Protocol)-based broadcasting, TLV (Type Length Value) is used as an interface between IP packets and modulation frames of the physical layer. For example, in broadcast services using MMT (MPEG Media Transport), MMTP (MMT Protocol) / UDP (User Datagram Protocol) / IPv6 / TLV packet sequences are stored in modulation frames and modulated into broadcast waves (non-patent References 1-4).

When an IP packet string belongs to the same IP data flow as one broadcast service, in this IP packet string, the source address/port number and the destination address/port number contained in the UDP/IP header are constant and do not change. . For this reason, there are cases where IP header compression is applied to an IP packet sequence in order to improve transmission efficiency during TLV conversion.

FIG. 9A shows an IP packet 100 before IP header compression. This IP packet 100 includes a payload 200 , an MMTP header 210 and a UDP/IPv6 header 220 . Also, FIG. 9B shows the TLV packet 110 after IP header compression. This TLV packet 110 includes a payload 200 , an MMTP header 210 , either a full header 230 or a partial header 240 and a TLV header 250 . Thus, IP header compression has transformed the UDP/IPv6 header 220 into either a full header 230 or a partial header 240 .

The majority of TLV packets 110S contain partial headers 240 that are heavily compressed UDP/IPv6 headers 220, resulting in smaller packet sizes. On the other hand, some TLV packets 110L include full headers 230 that are inserted periodically regardless of the type of payload 200, so the packet size does not change significantly from before IP header compression. For example, the 48-byte UDP/IPv6 header 220 is compressed into a 3-byte partial header 240, while the full header 230 is 45 bytes. The full header 230 and the partial header 240 are specified in Non-Patent Document 5, and the partial header 240 is sometimes called a compressed header. Non-Patent Document 3 defines an example of a method of using IP header compression in a broadcasting service.

In addition to the MMT method, DASH/ROUTE (Dynamic Adaptive Streaming over HTTP/Real -Time Object Delivery over Unidirectional Transport) method is also known (Non-Patent Document 4). In MMT, a payload to which an MMTP payload header is added is added to an encoded audio/video signal, and an MMTP/UDP/IP header is added to transmit the payload. On the other hand, in DASH/ROUTE, an encoded audio/video signal is transmitted as a segment file using LCT (Layer Coding Transport)/ALC (Asynchronous Layered Coding)/UDP/IP packets.

ISO/IEC 23008-1, “High efficiency coding and media delivery in heterogeneous environments: MPEG media transport” ARIB STD-B60, "Media transport method by MMT in digital broadcasting" ARIB TR-B39, "Advanced Broadband Satellite Digital Broadcasting Operational Regulations (Volume 3)" ATSC Standard: A/331, "Signaling, Delivery, Synchronization, and Error Protection" ARIB STD-B32, "Video coding, audio coding and multiplexing methods in digital broadcasting"

Here, as shown in FIG. 9C, a TLV packet 110 may be stored in a UDP/IPv4 packet 120 as an IP transmission format between sending/transmitting facilities inside and outside a broadcasting station or in an IP network. However, the UDP/IPv4 packet 120L includes the TLV packet 110L in which the full header 230 is stored in addition to the 28-byte UDP/IPv4 header 260 added. Therefore, the packet size of the UDP/IPv4 packet 120L exceeds the MTU (Maximum Transmission Unit) size (for example, 1500 bytes) of general IP lines/equipment, and may not be transmitted normally. In FIG. 9, when the IP packet 100 is configured to be 1491 bytes, for example, the UDP/IPv4 packet 120L is 1520 bytes and exceeds the MTU size, whereas the UDP/IPv4 packet 120S is 1478 bytes which is less than the MTU size. and does not exceed the MTU size. Although the TLV packet 110 may be stored in a UDP/IPv6 packet and transmitted, the data size of the UDP/IPv6 header is larger than the UDP/IPv4 header 260, so the MTU size is likely to be exceeded.

As a countermeasure, it is necessary to introduce high-cost equipment for jumbo packets exceeding 1,500 bytes in transmission/transmission equipment of broadcasting stations. Furthermore, in broadcast retransmission, it is also necessary to use the division TLV method, which has a large overhead, in order to enable the transmission of jumbo packets on existing lines and facilities. The divided TLV method is a method of subdividing TLV packets into MPEG-2 TS (Transport Stream) packets, storing them in IP packets, and transmitting them by TS Over IP, which is transmitted over IP lines.

Also, in order to prevent the TLV/UDP/IP packet including the full header from exceeding the MTU size, a method of reducing the fragment size of the IP packet payload stored in all TLV packets is also conceivable. However, with this method, the overhead ratio of IP packets increases, and the transmission efficiency of broadcast signals decreases. Various definitions of the IP packet overhead ratio are possible. For example, when the data size up to the MMTP/UDP/IP header is A, and the data size (fragment size) of the payload above MMTP is B, A/(A+B) can be defined as the overhead ratio. The closer the overhead ratio is to '0', the higher the transmission efficiency, and the closer to '1', the lower the transmission efficiency.

Accordingly, it is an object of the present invention to provide a broadcast signal converter and its program that can prevent the MTU size from exceeding and suppress the deterioration of transmission efficiency.

In order to solve the above problems, a broadcast signal conversion apparatus according to the present invention is a broadcast signal conversion apparatus that converts IP packets of a broadcast signal into TLV packets so that the size becomes equal to or less than a predetermined target size at the time of IP transmission. section, a multiplexing processing section, and a TLV conversion section.

According to such a configuration, the broadcast signal converter receives the first fragment size set so that the size of the TLV packet storing the full header during IP transmission is equal to or less than the target size to the fragment part. This target size is a value determined according to the operation, with one requirement not to exceed the MTU size. Then, the fragmentation unit fragments the control information so that the payload is equal to or smaller than the input first fragment size. If the payload including the entire control information does not meet the first fragment size, the payload includes the entire control information without fragmentation.

In the broadcast signal converter, the payloads of the encoded and fragmented video signal and audio signal are input by the multiplexing processing unit, and the fragmentation unit stores the fragmented control information and payloads of the video signal and the audio signal. A multiplexed signal of IP packets is generated.
Furthermore, the broadcast signal converter converts the IP packet storing the payload of the control information fragmented so as to have a payload smaller than the first fragment size into a TLV packet including a full header by the TLV converter.

In this way, the broadcast signal conversion device makes the first fragment or the whole of the control information a payload of a first fragment size or less considering the insertion of the full header, and then converts it into a TLV / UDP / IP packet that stores the full header. , it is possible to prevent the MTU size from being exceeded in general IP lines and facilities, and to enable IP transmission of TLV packets. Furthermore, since the broadcast signal conversion apparatus does not need to reduce the fragment size of the payload stored in all IP packets, the overhead ratio of IP packets does not increase significantly, and the reduction in transmission efficiency can be suppressed.

The present invention can also be realized by a program for causing a computer to function as the broadcast signal conversion device described above.

According to the present invention, it is possible to prevent the MTU size from exceeding and suppress the deterioration of the transmission efficiency.

1 is a block diagram showing the configuration of a broadcast signal converter according to an embodiment; FIG. In the embodiment, (a) is an IP packet multiplexed signal before IP header compression, (b) is a TLV packet after IP header compression, and (c) is an explanatory diagram of a TLV packet during IP transmission. In an embodiment, (a) and (b) are explanatory diagrams of payloads. FIG. 4 is an explanatory diagram illustrating fragments of a control signal in an embodiment; 4 is a flowchart showing the operation of a control signal generator in an embodiment; In an embodiment, it is a flow chart which shows operation of a TLV conversion part. 10 is a flowchart showing the operation of the control signal generator in the modified example; In a modified example, it is a flowchart which shows operation|movement of a TLV conversion part. In the prior art, (a) is an IP packet before IP header compression, (b) is a TLV packet after IP header compression, and (c) is an explanatory diagram of a TLV packet during IP transmission.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, each embodiment described below is for embodying the technical idea of the present invention, and unless there is a specific description, the present invention is not limited to the following. Further, the same reference numerals may be given to the same means, and the description thereof may be omitted.

[Configuration of broadcast signal converter]
A configuration of a broadcast signal conversion device 1 according to an embodiment will be described with reference to FIG.
The broadcast signal conversion device 1 converts an IP packet of a broadcast signal into a TLV/UDP/IP packet (TLV packet) so that the IP transmission of the TLV packet does not exceed a predetermined target size. As shown in FIG. 1, the broadcast signal converter 1 includes a video encoder 10, an audio encoder 20, a control information generator (fragmenter) 30, a multiplexing processor 40, and a TLV converter 50. and a fragment size calculator 60 .

The video encoding unit 10 receives a video signal and encodes the input video signal. For example, the video encoding unit 10 may use H.264. A video signal is encoded by a general video encoding method such as H.265/HEVC (High Efficiency Video Coding). At this time, the video encoding unit 10 may fragment the video signal so that the payload is equal to or smaller than the basic fragment size (second fragment size) input from the fragment size calculation unit 60 described later. The video encoding unit 10 then outputs the payload of the encoded and fragmented video signal to the multiplexing processing unit 40 .

Fragmentation is to divide desired data such as a video signal, an audio signal, control information, etc. into a predetermined size or less for storing as the payload of an IP packet.
In addition, the full header target fragment size (first fragment size) is the size of the TLV/UDP/IP packet that stores the first fragment or the entire control information during IP transmission of the TLV packet, after the full header is inserted by IP header compression. However, it is set to be less than the target size. Here, the target size can be arbitrarily set, for example, MTU size=1500 bytes.
In addition, the basic fragment size (second fragment size) is set so that the sizes of TLV/UDP/IP packets other than the above are equal to or smaller than the target size even after partial headers are inserted by IP header compression. and is larger than the full-header target fragment size.

The voice encoding unit 20 receives a voice signal and encodes the input voice signal. For example, the audio encoding unit 20 encodes the audio signal using a general audio encoding method such as AAC (Advanced Audio Coding). At this time, the speech encoding unit 20 may fragment the speech signal so that the payload is equal to or smaller than the basic fragment size input from the fragment size calculation unit 60 . The speech encoder 20 then outputs the payload of the encoded and fragmented speech signal to the multiplexing processor 40 .

Note that the payload of the video signal output by the video encoding unit 10 and the payload of the audio signal output by the audio encoding unit 20 may not be encoded data. For example, when the multiplexing method is MMT, the MMTP payload format with the MMTP payload header added, and when the multiplexing method is DASH / ROUTE, the ISOBMFF (ISO Base Media File Format) segment file format, based on the basic fragment size It may be fragmented.

The control information generation unit 30 receives the full-header target fragment size from the fragment size calculation unit 60, and fragments the control information so that the payload becomes equal to or less than the input full-header target fragment size. However, if the payload including the entire control information is smaller than the fragment size for the full header, the control information generator 30 generates the payload including the entire control information without fragmentation. In this embodiment, the control information generator 30 generates a PA (Package Access) message including MPT (MMT Package Table), which is control information defined in Non-Patent Document 2.

In addition, the control information generation unit 30 receives the basic fragment size from the fragment size calculation unit 60, and converts the rest of the unfragmented control information to the full-header target fragment size so that the payload is equal to or smaller than the input basic fragment size. fragment. The control information generator 30 then outputs the fragmented control signal to the multiplexing processor 40 .

Here, there are cases where the transmission cycle of the full header may be longer than the transmission cycle of the control information serving as the entry point. In this case, it is not necessary to insert a full header into all IP packets including the leading fragment of the control information serving as the entry point. Therefore, the control information generation unit 30 fragments the head fragment of the control information or the entire control information with the full-header target fragment size at each full-header transmission interval set in advance. The full-header transmission interval represents the interval at which full-headers are transmitted, that is, the interval at which full-headers are inserted into IP packets. For example, if the entry point control information transmission cycle is 100 milliseconds or less and the full header transmission cycle is 500 milliseconds or less, the full header should be inserted only once out of five control information transmissions (full header transmission interval = 5).

The multiplexing processing unit 40 receives the payloads of the encoded and fragmented video and audio signals, and multiplexes the IP packets storing the control information fragmented by the control information generation unit 30 and the payloads of the video and audio signals. It generates a signal. That is, the multiplexing processing unit 40 receives the payload of the video signal input from the video encoding unit 10, the payload of the audio signal input from the audio encoding unit 20, and the control signal input from the control information generating unit 30. are multiplexed as IP packets of the same IP data flow. For example, the multiplexing processing unit 40 performs multiplexing using a general multiplexing method such as MMT or DASH/ROUTE. The multiplexing unit 40 then outputs a multiplexed signal of IP packets storing the payloads of the video signal, the audio signal, and the control signal to the TLV conversion unit 50 .

The TLV conversion unit 50 converts an IP packet storing a payload of control information fragmented so as to have a payload smaller than the full-header target fragment size into a TLV/UDP/IP packet including a full-header. In addition, the TLV conversion unit 50 converts payload IP packets containing control information fragmented with the basic fragment size into TLV/UDP/IP packets containing partial headers. At this time, the TLV converter 50 applies IP header compression to the IP packet multiplexed signal input from the multiplexing processor 40 . Then, the TLV converter 50 IP-transmits the IP header-compressed TLV/UDP/IP packet.

In this embodiment, the TLV conversion unit 50 converts the IP packet of the payload containing the control information fragmented with the full-header target fragment size into a TLV packet containing the full-header at each full-header transmission interval. Also, in this embodiment, the TLV converter 50 stores the converted TLV packet in a UDP/IPv4 packet.

The fragment size calculator 60 calculates a full header target fragment size and a basic fragment size from a preset target packet size. This target packet size represents the target size of TLV packets (TLV/UDP/IP packets) during IP transmission, and is set to be equal to or less than the MTU size. The fragment size calculator 60 then outputs the calculated full-header target fragment size and basic fragment size to the control information generator 30 . Furthermore, the fragment size calculator 60 outputs the calculated basic fragment size to the video encoder 10 and the audio encoder 20 .

<Conversion of TLV packet>
2 and 3, the conversion of TLV packets will be described in detail.
FIG. 2(a) shows a multiplexed signal of the IP packet 100 before the IP header is compressed by the TLV converter 50. FIG. As shown in FIG. 2A, the multiplexed signal of IP packet 100 (100A, 100B) includes payload 200 (200A, 200B), MMTP header 210, and UDP/IPv6 header 220. FIG. Here, the multiplexing processing unit 40 adds an MMTP header 210 and a UDP/IPv6 header 220 .

As shown in FIG. 3, the payload 200 includes a video signal 300 encoded by the video encoding unit 10, an audio signal 310 encoded by the audio encoding unit 20, or a control signal fragmented by the control information generation unit 30. 320 (320A, 320B) is stored. Here, the control signal 320A is fragmented so as to have a payload smaller than the fragment size for the full header, whereas the control signal 320B is fragmented so as to have a payload smaller than the basic fragment size. Therefore, the payload 200A storing the control signal 320A is smaller in size than the payload 200B storing the control signal 320B.

FIG. 2(b) shows the TLV packet 110 after the IP header is compressed by the TLV converter 50. As shown in FIG. As shown in FIG. 2B, the TLV packet 110 (110A, 110B) includes a payload 200 (200A, 200B), an MMTP header 210, either a full header 230 or a partial header 240, and a TLV header 250. I'm in. Here, the TLV conversion unit 50 compresses the UDP/IPv6 header 220 into either a full header 230 or a partial header 240 and adds a TLV header 250 to it.

FIG. 2(c) shows a TLV packet (UDP/IPv4 packet 120) during IP transmission. As shown in FIG. 2(c), UDP/IPv4 packet 120 includes TLV packet 110 (110A, 110B) and UDP/IPv4 header 260. As shown in FIG. Here, the TLV converter 50 adds the UDP/IPv4 header 260 .

As described above, since the size of the full header 230 is as large as 45 bytes compared to the partial header 240 of 3 bytes, the UDP/IPv4 packet 120L exceeds the MTU size (see FIG. 9). In anticipation of this, as shown in FIG. 4, the control information generator 30 fragments the head fragment (control signal 320A) of the control signal 320 as a payload 200A of the full header target fragment size. On the other hand, the remaining fragment (control signal 320B) of the control signal 320 that was not fragmented with the full-header target fragment size is fragmented by the control information generator 30 as a payload 200B with the basic fragment size.

As a result, as shown in FIG. 2(b), a TLV packet 110A containing a payload 200A fragmented with a full-header target fragment size and a full header 230 becomes a TLV packet 110B containing a payload 200B with a basic fragment size and a partial header 240. be the same size. Therefore, as shown in FIG. 2(c), during IP transmission, even if the UDP/IPv4 header 260 is added to the TLV packet 110A, the UDP/IPv4 packet 120A will fit within the MTU size or less. In the example of FIG. 2(c), both UDP/IPv4 packets 120A and 120B are 1500 bytes or less.

<Calculation of full header target fragment size and basic fragment size>
Calculation of the full-header target fragment size and the basic fragment size will be described in detail below.
The fragment size calculation unit 60 subtracts the size of the UDP/IPv4 header to be added to the TLV packet, the header size of the TLV packet including the full header, and the header size of the multiplexing method from the target packet size. Calculate the fragment size. By constructing the payload using this full-header target fragment size, the size of the TLV packet that stores the head fragment or the whole of the control information during IP transmission becomes equal to or smaller than the MTU size.

Further, the fragment size calculation unit 60 subtracts the size of the UDP/IPv4 header, the size of the TLV packet including the partial header, and the size of the header of the multiplexing method from the target packet size, thereby obtaining the basic fragment size. calculate.

Here, for example, MMT is adopted as the multiplexing method, and the MMTP header is operated with packet_counter_flag=0 and extension_flag=0. Also, MMTP/UDP/IPv6 packets are stored in TLV packets, and IP transmission is performed using TLV/UDP/IPv4 packets. That is, the fragment size is calculated based on the data structure based on the MMTP payload including the MMTP payload header.

In this example, the target packet size, etc. are as follows.
Target packet size: 1478 bytes UDP/IPv4 header: 28 bytes (8 bytes for UDP + 20 bytes for IPv4)
Header size of TLV packet including full header: 49 bytes (TLV sync 1 byte + type 1 byte + length 2 bytes + full header 45 bytes)
Header size of TLV packet including partial header: 7 bytes (TLV sync 1 byte + type 1 byte + length 2 bytes + partial header 3 bytes)
MMTP header size: 12 bytes

In this example, the full header target fragment size is 1478-28-49-12=1389 bytes. Also, the basic fragment size is 1478-28-7-12=1431 bytes.

Note that even if the operation of the MMTP header (packet_counter_flag, extension_flag) is different, the increase in the header size is determined according to the operation method, so the basic fragment size can be calculated. Also, if the operation differs depending on the type of payload such as video signal, audio signal, and control information, the basic fragment size may be calculated for each. That is, the basic fragment size of the video signal and the audio signal may be different from the basic fragment size of the control information.

[Operation of control information generator]
The operation of the control information generator 30 will be described with reference to FIG.
As shown in FIG. 5, the control information generator 30 resets the counter to 0 in step S1.
In step S2, the control information generation unit 30 determines whether or not a timer interrupt instructing transmission of control information has occurred. For example, the timer interrupt includes a constant cycle timer that counts down or counts up a variable from a certain initial value with a certain clock and generates an interrupt when the variable reaches a certain set value. As a result, the control information can be generated and transmitted at regular intervals by generating interrupts at regular intervals such as 100 milliseconds.

If a timer interrupt has occurred (Yes in step S2), the control information generator 30 proceeds to the process of step S3.
If no timer interrupt occurs (No in step S2), the control information generator 30 returns to the process of step S2. In other words, the control information generator 30 is idle until a timer interrupt occurs.

In step S3, the control information generator 30 generates control information.
In step S4, the control information generator 30 determines whether or not the counter is zero.
If the counter is 0 (Yes in step S4), the control information generator 30 proceeds to the process of step S5.
If the counter is not 0 (No in step S4), the control information generator 30 proceeds to the process of step S6.

In step S5, the control information generation unit 30 fragments the head fragment of the control information with a full-header target fragment size.
In step S6, the control information generator 30 fragments the head of the control information with the basic fragment size.
In step S<b>7 , the control information generator 30 outputs the fragmented control information to the multiplexing processor 40 .

In step S8, the control information generator 30 determines whether or not the output of the entire control information has been completed.
When the output of the entire control information is completed (Yes in step S8), the control information generator 30 proceeds to the process of step S9.
If the output of the entire control information has not been completed (No in step S8), the control information generator 30 proceeds to the process of step S11.

In step S9, the control information generator 30 adds 1 to the counter.
In step S10, the control information generator 30 determines whether the counter is equal to the full header transmission interval.
If the counter is equal to the full-header transmission interval (Yes in step S10), the control information generator 30 returns to step S1.
If the counter is not equal to the full-header transmission interval (No in step S10), the control information generator 30 returns to step S2.

In step S11, the control information generator 30 fragments the rest of the control information with the basic fragment size. After that, the control information generator 30 returns to the process of step S7.

[Operation of TLV converter]
The operation of the TLV conversion unit 50 will be described with reference to FIG.
As shown in FIG. 6, the TLV conversion unit 50 resets the counter to 0 in step S20.
In step S21, the IP packet of the multiplexed signal is input to the TLV converter 50. FIG.

In step S22, the TLV conversion unit 50 determines whether the IP packet input in step S21 is an IP packet including the head fragment or the whole of the entry point control information.

Here, when MMT is used as the multiplexing method, the IP packet with packet_ID of '0' and fragmentation_indicator of '0' or '1' corresponds to the IP packet containing the first fragment or the whole of the control information of the entry point. . In this case, the target for inserting the full header is an IP packet containing the first fragment of the PA message transmitted by MMTP/UDP/IPv4 with Packet_ID=0, or an IP packet containing the entire PA message. An IP packet containing the top fragment has fragmentation_indicator=1, and an IP packet containing the entire PA message has fragmentation_indicator=0.

Also, when DASH/ROUTE is used as the multiplexing method, the TSI (Transport Session Identifier) is '0' and the TOI (Transport Object Identifier) is an LCT/ALC/UDP/IP packet of '0', and the following conditions corresponds to an IP packet containing the head fragment or the whole of the control information of the entry point. The aforementioned condition is that the close_object_flag of the previous IP packet is '1' among the IP packets with TSI=0 and TOI=0. In this case, the target for inserting the full header is a packet containing the head fragment of the file object transmitted by the LCT/ALC/UDP/IP packet with TSI=0 and TOI=0, or an IP packet containing the entire file object. In ROUTE, there is no flag that plays the same role as the fragmentation_indicator of MMT, but it is found by close_object_flag='1' that the packet contains the end of the file object. Furthermore, a packet that does not split the file object and sends the entire file object in one packet can be found by close_object_flag='1'. Therefore, among IP packets with TSI = '0' and TOI = '0', the next IP packet from the IP packet with close_object_flag = '1' is the first packet of the fragment of the file object, or the entire file object. is an IP packet containing a full header, and is a target packet for inserting a full header.

If it corresponds to the IP packet (Yes in step S22), the TLV conversion unit 50 proceeds to the process of step S23.
If it does not correspond to the IP packet (No in step S22), the TLV conversion unit 50 proceeds to the process of step S26.

In step S23, the TLV conversion unit 50 determines whether the size of the TLV/UDP/IP packet does not exceed the target packet size even if the full header is included during IP transmission. That is, the TLV conversion unit 50 calculates backward the size of the UDP/IPv4 packet 120A in FIG. 2(c) and determines whether or not the size exceeds the target packet size.
It should be noted that the threshold value of the IP packet size may be obtained in advance at the start of processing so that the target packet size is not exceeded after the full header is inserted. In this case, in step S23, determination may be made by comparing the threshold with the size of the input IP packet.

If the target packet size is not exceeded (Yes in step S23), the TLV conversion unit 50 proceeds to processing in step S24.
If the target packet size is exceeded (No in step S23), the TLV conversion unit 50 proceeds to the process of step S26.

In step S24, the TLV conversion unit 50 determines whether or not the counter is 0.
When the counter is 0 (Yes in step S24), the TLV conversion unit 50 proceeds to the process of step S25.
If the counter is not 0 (No in step S24), the TLV conversion unit 50 proceeds to the process of step S26.

In step S25, the TLV converter 50 converts the IP packet input in step S21 into a TLV packet including a full header. That is, the TLV converter 50 performs IP header compression on the IP packet 100A of FIG. 2(a) and adds the UDP/IPv4 header 260 to generate the UDP/IPv4 packet 120A of FIG. 2(c).

In step S26, the TLV converter 50 converts the IP packet input in step S21 into a TLV packet including a partial header. That is, the TLV conversion unit 50 performs IP header compression on the IP packet 100B of FIG. 2(a) and adds the UDP/IPv4 header 260 to generate the UDP/IPv4 packet 120B of FIG. 2(c). After that, the TLV conversion unit 50 proceeds to the process of step S30.

In step S27, the TLV conversion unit 50 adds 1 to the counter.
In step S28, the TLV conversion unit 50 determines whether or not the counter is equal to the full header transmission interval.
If the counter is equal to the full header transmission interval (Yes in step S28), the TLV conversion unit 50 proceeds to processing in step S29.
If the counter is not equal to the full-header transmission interval (No in step S28), the TLV conversion unit 50 proceeds to processing in step S30.

In step S29, the TLV conversion unit 50 resets the counter to 0.
In step S30, the TLV conversion unit 50 transmits the TLV packets converted in steps S25 and S26 to the IP transmission line. After that, the TLV conversion unit 50 returns to the process of step S21.

[Action/Effect]
In this way, the broadcast signal conversion device 1 reduces the size of the head fragment of the control information or the entire payload in consideration of the insertion of the full header, compared with other payloads, and then stores the full header in TLV/UDP/ By using IP packets, IP transmission of TLV packets becomes possible while preventing an excess of the MTU size in general IP lines/equipment. Furthermore, since the broadcast signal converter 1 does not need to reduce the fragment size of the payload stored in all IP packets, the overhead ratio of IP packets does not rise much, and the reduction in transmission efficiency can be suppressed.

Although the embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and includes design changes and the like within the scope of the present invention.

(Modification 1)
In the above-described embodiment, the fragmentation is performed with the full-header target fragment size based on the control information transmission frequency and the frequency thinned out by the full-header transmission interval. However, the present invention is not limited to this. When the entry point control information and the full header insertion cycle are the same, the full header transmission interval may be set to 1, or the full header transmission interval itself may not be considered. Hereinafter, as a modification 1, operations of the control information generation unit 30 and the TLV conversion unit 50 when not considering the full-header transmission interval will be described.

[Operation of control information generator]
The operation of the control information generator 30 will be described with reference to FIG.
As shown in FIG. 7, in step S30, the control information generator 30 determines whether or not a timer interrupt instructing transmission of control information has occurred.

If a timer interrupt has occurred (Yes in step S30), the control information generator 30 proceeds to the process of step S31.
If the timer interrupt does not occur (No in step S30), the control information generator 30 returns to the process of step S30. In other words, the control information generator 30 is idle until a timer interrupt occurs.

In step S31, the control information generator 30 generates control information.
In step S32, the control information generation unit 30 fragments the head fragment of the control information with the full-header target fragment size.
In step S<b>33 , the control information generator 30 outputs the fragmented control information to the multiplexing processor 40 .

In step S34, the control information generator 30 determines whether or not the output of the entire control information has been completed.
When the output of the entire control information is completed (Yes in step S34), the control information generator 30 returns to the process of step S30.
If the output of the entire control information has not been completed (No in step S34), the control information generator 30 proceeds to the process of step S35.
In step S35, the control information generator 30 fragments the rest of the control information with the basic fragment size. After that, the control information generator 30 returns to the process of step S33.

[Operation of TLV converter]
The operation of the TLV conversion unit 50 will be described with reference to FIG.
As shown in FIG. 8, IP packets of multiplexed signals are input to the TLV converter 50 in step S40.

In step S41, the TLV conversion unit 50 determines whether the IP packet input in step S40 is an IP packet including the head fragment or the entire entry point control information.

If it corresponds to the IP packet (Yes in step S41), the TLV conversion unit 50 proceeds to the process of step S42.
If it does not correspond to the IP packet (No in step S41), the TLV conversion unit 50 proceeds to the process of step S44.

In step S42, the TLV conversion unit 50 determines whether the size of the TLV packet does not exceed the target packet size even if the full header is included.
If the target packet size is not exceeded (Yes in step S42), the TLV conversion unit 50 proceeds to processing in step S43.
If the target packet size is exceeded (No in step S42), the TLV conversion unit 50 proceeds to the process of step S44.

In step S43, the TLV converter 50 converts the IP packet input in step S40 into a TLV packet including a full header.
In step S44, the TLV converter 50 converts the IP packet input in step S40 into a TLV packet including a partial header.
In step S45, the TLV converter 50 IP-transmits the TLV packets converted in steps S43 and S44. After that, the TLV conversion unit 50 returns to the process of step S40.

(Variation thereof)
In the above-described embodiment, the control information generator generates the control information, but the control information may be input to the control information generator from the outside.

In the above-described embodiment, the control information generating unit 30 is described as generating a PA message containing MPT, which is the control information specified in Non-Patent Document 2, but with the control information specified in Non-Patent Document 2 A PA message containing a PLT (Package List Table) may be generated. When a PLT is used as a service entry point and is transmitted by a PA message with Packet_ID=0, an MPT referenced from the PLT can also be transmitted by a PA message other than Packet_ID=0. In this case, since PA messages other than Packet_ID=0 are not service entry point control information, they may be fragmented so that the payload is smaller than the basic fragment size.

A payload other than a video signal and an audio signal may be input to the multiplexing processing unit 40 from an encoding device or the like (not shown). For example, in the case of broadcasting services, the multiplexing processing unit 40 may multiplex payloads of data broadcasting and caption data in addition to video signals and audio signals. At this time, data broadcasting and caption data may be fragmented so as to have a payload smaller than the basic fragment size.

The payload 200 and the MMTP header 210 are input to the TLV conversion unit 50 without adding a UDP/IP header in the multiplexing processing unit 40, and the TLV conversion unit 50 directly adds either the full header 230 or the partial header 240. may be configured. In other words, the process can be simplified by omitting the step of FIG.

In the above-described embodiment, in step S22 or step S41, when the TLV conversion unit 50 determines whether or not the input IP packet is an IP packet containing the first fragment or the entirety of the control information of the entry point, the MMT Alternatively, the DASH/ROUTE header is analyzed and determined, but the method is not limited to this method.
For example, the control information generation unit 30 may add a label indicating that a full header can be inserted to a packet containing the first fragment or the entire payload of the control information fragmented with the full-header target fragment size. Then, the TLV conversion unit 50 may determine whether or not the IP packet is a full-header target based on this label, and convert the IP packet to which this label is added to a TLV packet including a full-header. This makes it possible to omit the process of analyzing the MMT or DASH/ROUTE headers. In this case, the labeled IP packet is considered to be fragmented with the full header target fragment size. Therefore, the process of step S23 or step S42 of determining whether the size of the TLV/UDP/IP packet does not exceed the target packet size even if the full header is included may be omitted.

In the above-described embodiment, the broadcast signal conversion device has been described as independent hardware, but the present invention is not limited to this. For example, the present invention can also be realized by a program for causing hardware resources such as a CPU, memory, and hard disk provided in a computer to function as the above-described broadcast signal conversion device. This program may be distributed via a communication line, or may be distributed by being written in a recording medium such as a CD-ROM or flash memory.

1 Broadcast signal conversion device 10 Video encoding unit 20 Audio encoding unit 30 Control information generation unit (fragment unit)
40 multiplexing processing unit 50 TLV conversion unit 60 fragment size calculation unit

Claims (10)

A broadcast signal converter for converting an IP packet of a broadcast signal into a TLV packet so that the packet size is less than or equal to a predetermined target size at the time of IP transmission,
A first fragment size is input that is set so that the size of a TLV packet that stores a full header during IP transmission is equal to or less than the target size, and the control information is fragmented so that the payload is equal to or less than the input first fragment size. a fragment part that
A multiplexing process in which payloads of encoded and fragmented video and audio signals are input, and a multiplexed signal of IP packets storing fragmented control information and payloads of the video signal and the audio signal is generated in the fragmentation section. Department and
a TLV conversion unit that converts an IP packet storing the payload of the control information fragmented so that the payload is equal to or smaller than the first fragment size, into a TLV packet including the full header;
A broadcast signal conversion device comprising: The fragmentation unit fragments the control information so that the payload is equal to or smaller than the first fragment size at each preset full-header transmission interval,
The TLV conversion unit converts an IP packet of a payload containing control information fragmented so as to have a payload of the first fragment size or less into a TLV packet containing the full header at each full header transmission interval. 2. The broadcast signal conversion device according to claim 1. The fragmentation unit further receives a second fragment size set larger than the first fragment size, fragments the leading portion of the control information so that the payload is equal to or smaller than the input first fragment size, and inputs the control information. Fragmenting the rest of the unfragmented control information with the first fragment size so that the payload is equal to or less than the second fragment size, and
3. The TLV converter converts an IP packet of a payload containing control information fragmented so as to have a payload smaller than the second fragment size into a TLV packet containing a partial header. 3. The broadcast signal conversion device according to 2. By subtracting the size of the UDP/IP header to be added to the TLV packet, the header size of the TLV packet including the full header, and the header size of the multiplexing method from the preset target packet size, the first Along with calculating the fragment size,
Fragment size for calculating the second fragment size by subtracting the size of the UDP/IP header, the header size of the TLV packet including the partial header, and the header size of the multiplexing scheme from the target packet size. 4. The broadcast signal conversion apparatus according to claim 3, further comprising a calculator. If the size of the TLV packet does not exceed the target packet size even if the full header is included, the TLV conversion unit converts the IP packet of the multiplexed signal including the control information fragmented with the first fragment size to the IP packet including the full header. 5. The broadcast signal conversion apparatus according to claim 4, wherein the conversion is made into TLV packets. When MMT is used as a multiplexing method, the TLV conversion unit converts an IP packet having a packet_ID of '0' and a fragmentation_indicator of '0' or '1' into a TLV packet including the full header. 6. The broadcast signal conversion device according to any one of claims 1 to 5. When DASH/ROUTE is used as a multiplexing method, the TLV conversion unit is limited to IP packets with TSI of '0' and TOI of '0'. 6. The broadcast signal conversion apparatus according to claim 1, wherein the IP packet is converted into a TLV packet containing the full header. The fragmentation unit adds a label indicating that the full header can be inserted to a packet containing control information fragmented so that the payload is equal to or smaller than the first fragment size,
8. The broadcast signal conversion apparatus according to claim 1, wherein the TLV converter converts the labeled IP packet into a TLV packet including the full header. a video encoding unit that encodes the video signal;
an audio encoder that encodes the audio signal;
9. The broadcast signal conversion apparatus according to any one of claims 1 to 8, further comprising: A program for causing a computer to function as the broadcast signal conversion device according to any one of claims 1 to 9.

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