JP5430477B2 - Multiplexing device and multiplexing method, separation device and separation method, and program - Google Patents

Description

  In the present invention, when multiplexing a plurality of transport streams (TS), a technique for time-division multiplexing in units of packets and time-division multiplexing in units of packets while maintaining the independence of the transport streams The present invention relates to a technique for separating a transport stream.

  Conventionally, a plurality of MPEG-2 TSs (transport streams defined in ISO / IEC (International Organization for Standardization: International Electrotechnical Commission) 13818-1) are kept independent. Thus, a method of transmitting a transmission line assuming a single TS has been proposed (see, for example, Patent Document 1 and Non-Patent Document 1).

  In this transmission method, a multiplexing device adds a header to a TS packet (fixed length (188 bytes) packet starting with a synchronization byte (0x47) or a packet with a fixed length parity byte added thereto). A periodic frame is generated, and TS packet sequences are multiplexed by using slot position information (hereinafter referred to as slot allocation information) for each TS packet accommodated in the slot of the frame. Further, the demultiplexer receives the multiplexed TS packet sequence frame, and uses the slot allocation information to demultiplex the TS packet sequence. The slot allocation information and necessary synchronization information are transmitted in a TS packet format header. Hereinafter, a frame composed of a TS packet format header and a TS packet is referred to as a multiplexed frame.

  Data to be transmitted using multiple frames is mainly for TS, but can be transmitted in the same way as TS if it is data of a fixed-length packet sequence starting with the same synchronization byte as TS. Therefore, neither “MPEG-2 TS” nor “data of a fixed-length packet sequence starting with a synchronization byte (0x47) like TS, but not compliant with ISO / IEC 13818-1” is described as TS. To explain.

  The slot assignment method applied to each TS applied to the above transmission scheme includes a static pre-assignment method in which the number of slots and slot positions to which each TS is assigned is fixed for each multiplex frame, and each A dynamic assignment method (demand assignment) is known in which the number of slots to which a TS is assigned and the slot position are changed as necessary (see, for example, Non-Patent Document 2).

(Dynamic allocation method)
When executing the dynamic allocation method, the multiplexing apparatus, for example, temporarily stores each TS in a buffer and allocates a slot to each TS according to a preset rule, such as allocating a slot from a TS having a large remaining buffer capacity, Multiplex TS. According to the dynamic allocation method, TS speed conversion required in the static allocation method to be described later becomes unnecessary, and a decrease in transmission efficiency can be suppressed.

(Static assignment method)
When executing the static allocation method, the multiplexing apparatus inserts a null packet into the TS and rewrites the value of the PCR (program clock reference) in the TS, thereby allocating the original speed of the TS. The speed is converted to a speed determined by the number (for example, see Non-Patent Document 3). Also, if the TS is “fixed-length packet string data that starts with a synchronization byte (0x47) as in the TS, but does not conform to ISO / IEC 13818-1”, a packet consisting of the synchronization byte and appropriate stuff data is inserted. By converting the speed. Hereinafter, the null packet and the “packet composed of the synchronization byte and appropriate stuff data” are not distinguished from each other and are referred to as a null packet. At the time of speed conversion, an integer number of slots to be allocated is determined so that the speed of the TS after conversion is higher than the original speed. This is to prevent the TS packet from being discarded without being assigned a slot.

  According to the static allocation method, if the total number of slots storing TS packets in a multiplex frame is Nd, the total number of slots storing headers is Nh, and the number of slots allocated to a certain TS is n, the TS speed is , Expressed as n / (Nd + Nh) times the transmission rate of all data including the headers of multiple frames. For this reason, the demultiplexer that receives multiple frames can easily perform clock recovery using a PLL or the like when recovering the clock of the TS.

  In addition, according to the static allocation method, since the number of slots and the slot position of each TS are fixed for each multiplex frame, the slot allocation information indicating the position of each TS in the multiplex frame does not change. Therefore, even if an error occurs in slot allocation information in a certain multiplex frame header due to the influence of noise or the like during transmission, the demultiplexer that receives the multiplex frame includes error detection means such as CRC. As a result, erroneous slot allocation information can be discarded. Then, TS can be correctly separated by using the correct slot allocation information received before that.

(Transmission by superframe)
By the way, apart from a transmission method that repeatedly transmits for each multiplex frame, a transmission method is known in which a superframe is configured with a preset number of multiplex frames and is repeatedly transmitted for each superframe (for example, non-patent). (Ref. 4). In this transmission method, the number of slots and the slot position assigned to each TS are not the same between multiple frames, but are the same and fixed between superframes. The demultiplexer that receives the superframe establishes synchronization of multiple frames, establishes superframe synchronization, acquires slot assignment information from each multiple frame header in the superframe, and assigns the number of slots assigned to each TS. Then, the slot position is specified and TS is separated.

  According to the superframe transmission scheme, when the number of multiplexed frames constituting a superframe is M, the TS speed for assigning L slots among all slots (Nd × M slots) in which TS packets are stored is Since the frame transmission rate is L / {(Nd + Nh) × M} times, the post-conversion rate can be set more finely. Therefore, speed conversion can be performed so that the amount of null packets to be inserted into each TS becomes smaller, and a decrease in transmission efficiency can be suppressed.

  Also, according to the superframe transmission scheme, the slot number and slot position of each TS are fixed for each superframe, so that the slot allocation information of M multiplexed frames constituting the superframe does not change. For this reason, even if an error occurs in one or more of the M slot allocation information due to the influence of noise or the like during transmission, the separating apparatus that receives the superframe is provided with error detection means such as CRC. By providing the above, it is possible to discard erroneous slot allocation information. Then, TS can be correctly separated by using the correct slot allocation information received before that.

Japanese Patent No. 3051729

ITU-T Rec. J. et al. 83, ITU-T Rec. J. et al. 183 “TDMA Communication”, The Institute of Electronics, Information and Communication Engineers, p140, 1989 Japan CATV Technology Association (JCTEA) Standard STD-002 “Digital Broadcast Baseband Batch Retransmission System Using Synchronous Multiplexing Using Frame Structure”, Video Information Media Society Technical Report, BCT 2006-159, pp. 31-36, Nov. 2006

  As described above, the dynamic allocation method, the static allocation method, and the superframe transmission method have various advantages. However, when the dynamic allocation method is executed, the transmission rate of all data including the header when using multiple frames and the rate of each transmitted TS may not be in a rational number ratio relationship. There has been a problem that a clock recovery circuit for recovering a TS clock is complicated in a separation device that receives multiple frames.

  Further, since the number of slots and the slot position of each TS change for each multiplex frame, the slot allocation information differs for each multiplex frame. For this reason, unlike the case of the static allocation method, the demultiplexer that receives multiple frames needs to correctly receive all slot allocation information. The separation device receives a multiplex frame affected by noise or the like during transmission, and when the slot allocation information in the multiplex frame is incorrect, the TS cannot be correctly separated for the multiplex frame. was there.

  On the other hand, when the static allocation method is executed, the number of slots to which each TS is allocated and the slot position are fixed for each multiplex frame, so that there is a problem that the TS speed cannot be flexibly handled. It was. In addition, since a null packet is inserted into the TS to perform speed conversion, there is a problem that transmission efficiency decreases.

  In the transmission method using a super frame, the number of multiplexed frames constituting the super frame is set in advance. For this reason, the demultiplexer that receives the superframe requires a certain time until the synchronization of the superframe is established regardless of the speed of each TS and the number of TSs to be multiplexed. If the time until this synchronization is established is long, the waiting time (for example, the waiting time when the channel arrangement is changed or the number of channels is increased) from when the separation device is started to when the service is started increases. It will be stressful for the user who receives the service.

  Therefore, the present invention has been made in view of the above problems, and its purpose is to assign a time slot of a transmission path to a plurality of TSs in a fixed manner, time-division multiplex, and multiplex frames and superframes. An object of the present invention is to provide a multiplexing apparatus and multiplexing method, a demultiplexing apparatus and a demultiplexing method, and a program capable of suppressing a decrease in transmission efficiency and shortening the time required for establishing superframe synchronization in a system configured and transmitted.

  In order to achieve the above object, according to the first aspect of the present invention, a time slot of a transmission path is fixedly assigned to a plurality of transport streams, the transport streams are time-division multiplexed, and one or more multiplexed frames are obtained. In the multiplexing apparatus that generates a superframe consisting of the above and outputs it to the transmission path, the number of multiplexed frames constituting the superframe is determined based on the speeds of the plurality of transport streams, and the data of the multiplexed frame is determined. Based on the slot allocation information, a slot allocation unit that generates slot allocation information in which the number and position of slots allocated to each transport stream when storing the plurality of transport streams in the slot, Convert the speed of the transport stream A degree conversion unit, a header generation unit that generates a multiplex frame header including the slot assignment information, and a rate-converted transport stream is stored in a data slot of the multiplex frame based on the slot assignment information and multiplexed. And a multiplexing unit that stores the multiplexed frame header in a header slot of the multiplexed frame and generates a super frame composed of multiplexed frames corresponding to the number of multiplexed frames.

  Further, the invention of claim 2 is the multiplexing device according to claim 1, wherein the rate conversion unit converts a rate by inserting a null packet into the transport stream, and the slot allocating unit includes the multiplexing unit. The number of multiplexed frames is determined and the slot allocation information is generated so that a transport stream is not lost in accordance with the conversion, and null packets inserted at the time of the speed conversion are minimized. And

The invention of claim 3 is the multiplexing device according to claim 2, wherein the number of transport streams is J (J is an integer), and the maximum value of the number of multiplexed frames is I (I is an integer). , A and B as parameters (A is a positive integer, B is a positive integer less than I), and the slot allocation is performed when the transport stream is speed-converted to allocate slots in units of 1 / I slots. The number of slots A ₁ + B ₁ is allocated to J transport streams so that the transport stream is not lost with the multiplexing and the number of null packets inserted during the speed conversion is minimized. _/ I~A J _{+ B} J / I were determined, _{respectively,} in the case of _{B 1 = ··· = B J =} 0 (1), determines the number of the multiplexed frames 1, not 0 _{B j} j is present following a positive integer) J, when I / _{B j} is for all non-0 _{B j} integer (2), the multi-frame number _{LCM {I / B j} (} LCM {} Represents the least common multiple), and when neither of the conditions (1) and (2) is satisfied, the number of multiplexed frames is determined as I.

Further, the invention of claim 4 is the multiplexing device according to claim 3, wherein the number of multiplexed frames is set to I when the slot allocation unit does not satisfy either of the conditions (1) and (2). Instead of determining, A and B are newly determined so as to satisfy the condition (1) or (2), and the number of multiplexed frames is determined as LCM {I / B _j }.

  Further, the invention of claim 5 is the multiplexing device according to any one of claims 1 to 4, wherein the header generation unit is configured to transmit a multiplexed frame constituting a superframe based on the slot allocation information. Position information indicating a relative position is generated, and a multi-frame header including the slot allocation information and the position information is generated.

  The invention according to claim 6 is the multiplexing device according to any one of claims 1 to 5, wherein the header generation unit determines whether the slot allocation information has changed based on the slot allocation information. Update information indicating the above is generated, and a multi-frame header including the slot allocation information and the update information is generated.

  Further, the invention of claim 7 is a separating apparatus for inputting a superframe output from the multiplexing apparatus according to claim 5 and separating a predetermined transport stream from the multiplexed frames constituting the superframe. Position information indicating a relative position of the multiplex frame from a multiplex frame header of the multiplex frame constituting the super frame, establishing synchronization of the multiplex frame constituting the super frame, establishing synchronization of the super frame Slot allocation information for acquiring slot allocation information for the number of multiplexed frames from a synchronization establishment unit for determining the number of multiplexed frames based on the position information and a multiplexed frame header of the multiplexed frames constituting the superframe Based on the acquisition unit and the slot allocation information, the slot A separation unit for separating a predetermined transport stream from the multiplex frames constituting the superframe, further comprising a characterized.

  The invention according to claim 8 is a separating apparatus for inputting a superframe output from the multiplexing apparatus according to claim 6 and separating a predetermined transport stream from the multiplexed frames constituting the superframe. , When obtaining update information indicating whether the slot assignment information has changed from a multiplex frame header of a multiplex frame constituting the super frame, and when determining that the slot assignment information has changed from the update information, If the synchronization of the multiplex frame and the synchronization of the super frame are established and it is determined that the slot allocation information has not changed from the update information, a synchronization establishment unit that establishes only the synchronization of the multiplex frame, and When synchronization and synchronization of the superframe are established, the superframe is Slot allocation information corresponding to the number of multiplexed frames is acquired and output from the multiplexed frame header of the generated multiplexed frame, and when only synchronization of the multiplexed frame is established, the slot allocation information that has already been acquired is output. An allocation information acquisition unit; and a separation unit that separates a predetermined transport stream from multiple frames constituting the superframe based on the slot allocation information output by the slot allocation information acquisition unit. And

  Furthermore, the invention of claim 9 assigns a time slot of a transmission path to a plurality of transport streams in a fixed manner, and time-division multiplexes the transport streams to generate a super frame composed of one or more multiplexed frames. Then, in the multiplexing method for outputting to the transmission path, a step of determining the number of multiplexed frames constituting the super frame based on the speed of the plurality of transport streams; Generating the slot allocation information in which the number and position of the slots allocated to each transport stream are stored, and the speed of the transport stream is determined based on the slot allocation information. Converting, and Generating a multiplex frame header including lot allocation information; and storing and multiplexing the rate-converted transport stream in a data slot of the multiplex frame based on the slot allocation information; The method includes a step of generating a super frame that is stored in a header slot of a frame and is composed of multiple frames corresponding to the number of multiplexed frames, and a step of outputting the super frame.

  Furthermore, in the invention of claim 10, by the multiplexing method of claim 9, a plurality of transport streams are multiplexed and stored in a data slot, and the number and position of the slots allocated to each transport stream are defined. A multiple frame header including a slot allocation information and a position information indicating a relative position of the multiplexed frame in a super frame configured by the multiplexed frame, the multiplexed frame having the data slot and the header slot. A separation method for inputting a superframe configured by the above and separating a predetermined transport stream from the multiplex frame, establishing a synchronization of the multiplex frames constituting the superframe, and configuring the superframe Multi-frame multi Obtaining position information from a frame header, establishing synchronization of the super frame based on the position information, obtaining a number of multiplexed frames, and from the multiplexed frame header of the multiplexed frames constituting the super frame, the multiplexed frame Obtaining a number of slot allocation information, and separating a predetermined transport stream from the multiplexed frames constituting the superframe based on the slot allocation information.

  The invention of claim 11 is a multiplexing program for causing a computer to function as the multiplexing device.

  The invention of claim 12 is a separation program for causing a computer to function as the separation device.

  According to the present invention, the multiplexing apparatus determines the number of multiplexed frames and slot allocation information based on the speed of the transport stream. As a result, the number of multiplexed frames constituting the superframe is an appropriate number based on the speed of the transport stream, so the size of the superframe can be reduced compared to the case where the number of superframes is preset. it can. Therefore, a decrease in transmission efficiency can be suppressed, and the time required for establishing superframe synchronization in the separation device can be shortened.

  Further, according to the present invention, in the separation device, the superframe output from the multiplexing device is input, slot allocation information for the number of multiplexed frames is obtained from the multiplexed frames constituting the superframe, and a predetermined transport is obtained. The stream was separated. Since the super frame is composed of an appropriate number of multiplexed frames so that the size of the super frame is reduced, the time required for establishing synchronization of the super frame can be shortened.

It is a block diagram which shows the structure of the multiplexing apparatus by embodiment of this invention. It is a flowchart which shows the process of a slot allocation part. It is a figure which shows the structural example (1) of a multi-frame and a super frame. It is a figure which shows the structural example of a multi-frame header. It is a figure which shows the structural example (2) of a multi-frame and a super frame. It is a figure which shows the structural example (3) of a multi-frame and a super frame. It is a block diagram which shows the structure of the separation apparatus by embodiment of this invention. It is a flowchart which shows the process of a synchronization establishment part. It is a flowchart which shows the process of a slot allocation information acquisition part. It is a figure which shows the structural example of the multiplex frame by a prior art. It is a figure which shows the structural example of the multiplex frame and super frame by a prior art.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[Multiplexer]
First, a multiplexing device according to an embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the multiplexing apparatus. The multiplexing apparatus 1 includes speed conversion units 10-1 to 10 -J, a slot allocation unit 11, a header generation unit 12, and a multiplexing unit 13. Multiplexer 1 assigns a time slot of a transmission path to a plurality of TSs in a fixed manner, that is, slots in a superframe are assigned to each TS so that the transmission amount of each superframe is the same for each TS Allocation and time division multiplexing are performed to form a multiplexed frame and a super frame, and the super frame is transmitted to a separation device to be described later via a transmission path.

  When J (J is an integer) TS1 to TSJ to be transmitted by the multiplexing apparatus 1 are input, the speed converters 10-1 to 10-J input TS1 to TSJ, respectively, and from the slot allocator 11 to TS1. The normalization rate after rate conversion for .about.TSJ (the rate obtained by normalizing the converted rate by the transmission rate per slot, that is, the number of assigned slots per multiplexed frame) is input. Then, the speed conversion units 10-1 to 10-J measure the speeds of the input TS1 to TSJ, respectively, convert the measured speed (original speed) into a normalized speed, and the converted original normalized speed and With respect to the difference between the normalized speed after the speed conversion, null packets are inserted into TS1 to TSJ, the PCR values are rewritten, and the TS1 to TSJ after the speed conversion are output to the multiplexing unit 13. For example, when the normalized speed measured and converted with respect to the input TS1 is 4.134, and the normalized speed after the speed conversion of TS1 is 4.2, the speed conversion unit 10-1 A null packet having a speed (4.2-4.134...) Corresponding to the difference between the two is inserted, and TS1 after the speed conversion is output. The speed conversion units 10-1 to 10-J input slot allocation information instead of the normalized speed from the slot allocation unit 11, calculate the normalized speed after speed conversion from the slot allocation information, and perform the original normalization. A null packet corresponding to the difference between the normalization speed and the normalized speed after speed conversion may be inserted into TS1 to TSJ. Details of the normalization speed will be described later.

  The slot allocating unit 11 inputs speed information (rate information) 1 to J of TS1 to TSJ, determines a normalized speed after speed conversion based on the speed information 1 to J, and forms multiple frames constituting a superframe (Number of multiplexed frames) is determined, and slot allocation information indicating the slot number and slot position of each TS stored in the multiplexed frame in the superframe is generated. Then, the slot allocation unit 11 outputs the normalized speed after the speed conversion to the speed conversion units 10-1 to 10-J, outputs the slot allocation information to the header generation unit 12 and the multiplexing unit 13, and the number of multiplexed frames Is output to the header generation unit 12.

  Here, the normalized speed after the speed conversion, the number of multiplexed frames, and the slot allocation information are determined and generated so that TS packets of TS1 to TSJ are not lost during multiplexing. That is, the number of assigned slots of each TS stored in the multiplex frame in the superframe is a speed determined by the number of assigned slots (speed converted by the speed converters 10-1 to 10-J) is higher than the original speed. It is decided to become. Details of processing for determining the normalized speed and the number of multiplexed frames after rate conversion, details of processing for generating slot allocation information, and details of slot allocation information will be described later.

  The slot allocation unit 11 may input preset speed information 1 to J when TS1 to TSJ are constant speeds. When TS1 to TSJ are variable speeds, the speed information 1 to J measured by the speed converters 10-1 to 10-J or the speed information measuring unit (not shown) may be input. In this case, the speed information measuring unit inputs TS1 to TSJ and measures speed information 1 to J based on TS1 to TSJ, respectively.

  The header generation unit 12 receives the slot allocation information and the number of multiplexed frames from the slot allocation unit 11, and generates the relative position information of the multiplexed frames constituting the superframe based on the slot allocation information and the number of multiplexed frames. Update information indicating whether or not the slot allocation information has changed is generated. The header generation unit 12 includes packet synchronization information, multiple frame synchronization information, slot allocation information, relative position information of the multiple frames constituting the super frame, and update information for each of the multiple frames constituting the super frame. A multiplex frame header is generated and output to the multiplexing unit 13. Details of the multiple frame header will be described later.

  Multiplexer 13 receives TS1 to TSJ after speed conversion from speed converters 10-1 to 10-J, receives slot assignment information from slot assigner 11, and receives a multiplexed frame header from header generator 12. To do. Then, based on the slot allocation information, the multiplexing unit 13 stores and multiplexes TS1 to TSJ in the data slot of the multiplexed frame, stores the multiplexed frame header in the header slot of the multiplexed frame, and stores the multiplexed frame and the superframe. Generate and output a superframe. The super frame output from the multiplexing unit 13 is transmitted as a broadcast wave from the multiplexing device 1 to a separation device to be described later via a transmission path of the broadcast network. Details of the superframe configuration will be described later.

(Slot allocation part)
Next, the slot allocation unit 11 shown in FIG. 1 will be described in detail. As described above, the slot assignment unit 11 determines the normalized speed after speed conversion and the number of multiplexed frames constituting the superframe based on the speed information 1 to J of TS1 to TSJ, and generates slot assignment information. . That is, the slot allocation unit 11 prevents the TS packets of TS1 to TSJ from being lost at the time of multiplexing based on the speed information 1 to J of TS1 to TSJ, that is, the TS speed (rate conversion unit) determined by the number of slots to be allocated. The normalized speed and the number of multiplexed frames after the speed conversion are determined so that the speed converted by 10-1 to 10-J is equal to or higher than the original speed, and slot allocation information is generated.

FIG. 2 is a flowchart showing the processing of the slot allocation unit 11. The slot allocation unit 11 inputs speed information 1 to J of TS1 to TSJ (step S201), and based on the speed information 1 to J, the speed of each TS determined by the number of allocated slots is determined. The number of allocated slots A ₁ + B ₁ / I to A _J + B _J / I of TS1 to TSJ is determined so that the null packet inserted at the time of speed conversion becomes the minimum or higher (step S202). ). Here, the number of assigned slots A ₁ + B ₁ / I to A _J + B _J / I of TS1 to TSJ is the number of assigned slots of each TS per multiplexed frame, and is the normalized speed after speed conversion. That is, the speed conversion is performed in the speed conversion units 10-1 to 10-J so that the slots in one multiplexed frame are assigned in units of 1 / I slots. I represents the maximum value of the number of multiplexed frames (integer) included in the superframe, and is set in advance. A is a positive integer, and B is a positive integer less than I. Thereby, the parameters A and B are determined for each TS according to the speed information 1 to J.

The slot allocation unit 11 determines the number of multiplexed frames included in the superframe according to the following rules.
(1) When all of B _{1 to} B _J are 0 (when B ₁ =... = B _J = 0), the number of multiplexed frames in the superframe is set to 1.
(2) When non-zero B _j (j is a positive integer equal to or less than J) exists and I / B _j is an integer for all B _j , the number of multiplexed frames in the superframe is represented by LCM {I / B _j }. LCM {} is a function for calculating the least common multiple.
(3) If none of the above (1) and (2) applies, the number of multiplexed frames in the superframe is I.

Specifically, the slot allocation unit 11 determines whether or not B _{1 to} B _J determined in step S202 is B _{1 to} B _J = 0 (step S203), and B _{1 to} B _J = 0. When it is determined that there is a frame (step S203: Y), the number of multiplexed frames is determined to be 1 (step S204). On the other hand, when it is determined that B _{1 to} B _J = 0 are not satisfied (step S203: N), the process proceeds to step S205.

Slot allocation unit 11, the _{B j} nonzero, all I / _{B j} is equal to or an integer (step S205), when all of the I / _{B j} for _{B j} nonzero is an integer If it is determined (step S205: Y), the number of multiplexed frames is determined to be LCM {I / B _j } (the least common multiple of I / B _j ) (step S206). On the other hand, is not an integer all I / B _j for B _j is not zero, i.e., if any of the I / B _j is determined not to be an integer (step S205: N), determines the number number of frames to I (Step S207). Let N be the number of multiplexed frames determined in steps S204, S206, and S207.

Then, the slot assignment unit 11 shifts from step S204, S206, S207, determined at step S202, TS1～TSJ the assigned slot number _{A 1 + B 1 / I~A J} + B J / I and, Based on the number N of multiplexed frames determined in steps S203 to S207, slot assignment information indicating the number of slots and slot positions of TS1 to TSJ stored in the N multiplexed frames constituting the superframe is generated (steps). S208). Here, the number of slots of TS1 to TSJ stored in N multiplexed frames constituting the superframe is multiplexed to A ₁ + B ₁ / I to A _J + B _J / I, which is the number of assigned slots per multiplexed frame. It is obtained by multiplying the number N of frames. In the N multiplexed frames constituting the superframe, among the slots storing data, the remaining slots other than the slots storing TS1 to TSJ are empty slots. Further, the slot positions (and empty slot positions) of TS1 to TSJ stored in N multiplexed frames constituting the superframe are arbitrarily determined.

  The slot allocation unit 11 outputs the normalized speed after the speed conversion to the speed conversion units 10-1 to 10-J, outputs the slot allocation information to the header generation unit 12 and the multiplexing unit 13, and sets the number of multiplexed frames as the header. It outputs to the production | generation part 12 (step S209).

  As described above, the slot allocation unit 11 determines the normalized speed after the speed conversion based on the speed information 1 to J of TS1 to TSJ according to the processing flow shown in FIG. The number is determined and slot allocation information is generated.

〔Concrete example〕
Next, specific examples of a process for determining the number of multiplexed frames, a process for generating slot allocation information, a process for generating a multiplexed frame header, and a process for generating a multiplexed frame and a superframe will be described. The number of TSs input by the multiplexing apparatus 1 is J = 4, and the transmission rates normalized by the transmission rate per slot in each TS are TS1 = 4.134, TS2 = 2.198, TS3 = 2. TS4 = 0.111... And the multiplexed frame is composed of a slot (data slot) for storing 11 data and a slot (header slot) for storing one header. In other words, the normalized speed for all slots storing data in one multiplexed frame is 11. Here, the transmission rate normalized by the transmission rate per slot (normalized rate) indicates a rate obtained by dividing the TS transmission rate by the transmission rate per slot. For example, when the transmission rate per slot is 1 Mbps and the input TS rate is 2 Mbps, the normalized rate is 2/1 = 2.

(Conventional example 1)
Before explaining a specific example of the processing of the multiplexing apparatus 1 according to the embodiment of the present invention, as a first example in the prior art, when a slot is fixedly assigned for each multiplex frame, that is, a superframe is not generated. The case will be described. In this case, since the minimum unit of the number of slots allocated to each TS is 1, the normalized speed of each TS after speed conversion is TS1 = 5, TS2 = 3, TS3 = 2, and TS4 = 1.

  FIG. 10 is a diagram showing a configuration example of a multiplex frame according to the prior art (configuration example when the normalized speed of each TS after rate conversion is TS1 = 5, TS2 = 3, TS3 = 2, TS4 = 1). . As shown in FIG. 10, according to the normalized speed of each TS after speed conversion, one slot for storing a header, five slots for storing TS1, three slots for storing TS2, TS3 Is generated, and a multi-frame consisting of one slot in which TS4 is stored is generated. All slots of the multiplex frame are assigned slots without converting the speed of the input TS with respect to the number of slots 11 excluding the header (for the normalized speed 11 of all slots storing data in the multiplex frame). In this case, the total number of slots (the sum of the normalized speeds in the input TS) is 8.442 (= 4.134 ... + 2.198 ... + 2 + 0.111 ...). Null packets are transmitted in the remaining band 2.557 (= 11-8.442).

(Conventional example 2)
Next, as a second example of the prior art (example of Non-Patent Document 4 described above), a case where a superframe having a preset size is generated and a slot is fixedly assigned to each superframe will be described. Assume that M = 10 is preset as the number of multiplexed frames constituting the superframe. In this case, since the minimum unit of the number of slots allocated to each TS is 0.1 (1 slot in 10 multiplexed frames), the normalized speed of each TS after speed conversion is TS1 = 4.2, TS2 = 2.2, TS3 = 2.0, and TS4 = 0.2.

  FIG. 11 shows a configuration example of a multiplex frame and a superframe according to the prior art (normalized speeds of TS after speed conversion are TS1 = 4.2, TS2 = 2.2, TS3 = 2.0, TS4 = 0.2 It is a figure which shows the example of a structure at that time. The multiplexing apparatus generates a multiplexed frame and a super frame shown in FIG. Of all the slots of the multiplex frame, the number of slots in which the header is excluded (for the normalized speed 11 of all the slots storing data in the multiplex frame) The sum (the sum of normalized speeds in TS after speed conversion) is 8.6 (= 4.2 + 2.2 + 2.0 + 0.2), and 2.4 per multiplexed frame (24 per superframe) Empty slots are generated. Further, the transmission rate of the null packet inserted along with the TS rate conversion is 0.157 (= 8.6−8.442,...). Since the empty slot can be used to transmit another TS, a decrease in transmission efficiency can be suppressed as compared with a case where a superframe is not transmitted.

(Embodiment 1: N = 5 when the number N of multiplexed frames is determined by the above (2))
Next, an embodiment of the multiplexing apparatus 1 shown in FIG. 1 will be described. First, a case where the rule (2) is satisfied in the rule for determining the number N of multiplexed frames (an example in which the number of multiplexed frames N = 5 is determined by the slot allocation unit 11) will be described. As described above, the number of TSs is J = 4, and the normalization speed (number of slots allocated per multiplexed frame) is set to TS1 = 4.134..., TS2 = 2.198. .., TS3 = 2, TS4 = 0.111, and the multiplex frame is composed of a slot for storing 11 data and a slot for storing one header, and the maximum value of the multiplex frames constituting the superframe Let I = 10.

The slot allocation unit 11 determines the number of allocated slots based on the normalized speeds TS1 = 4.134..., TS2 = 2.198..., TS3 = 2, TS4 = 0.111. speed of each TS becomes more original speed determined by the assigned number of slots of the time, and, as a null packet which is inserted when the rate conversion is minimized, the number of allocated slots each TS a _{1 +} B _{1 /} 10~A determining a ₄ + _{B 4/10.} That is, the number of assigned slots for TS1 is 4.2 (= 4 + 2/10), the number of assigned slots for TS2 is 2.2 (= 2 + 2/10), the number of assigned slots for TS3 is 2.0 (= 2 + 0/10), The number of slots assigned to TS4 is 0.2 (= 0 + 2/10), A ₁ = 4, B ₁ = 2, A ₂ = 2, B ₂ = 2, A ₃ = 2 and B ₃ = 0, A ₄ = 0, B ₄ = 2.

  The speed conversion units 10-1 to 10-4 input the normalized speed (number of slot allocations per multiplexed frame) after the speed conversion of the corresponding TS from the slot allocation unit 11 (input slot allocation information, The normalized speed after speed conversion is calculated from the slot allocation information), and a null packet is inserted for the difference between the original normalized speed of the corresponding TS and the normalized speed after speed conversion. For example, the speed conversion unit 10-1 inputs the normalized speed 4.2 after the speed conversion of TS1, and the original normalized speed TS1 = 4.134... Of TS1 and the normalized speed TS1 = after the speed conversion. For the difference from 4.2, rate conversion is realized by inserting null packets for the transmission rate of 4.2-4.134.

From the determined parameters B ₁ = 2, B ₂ = 2, B ₃ = 0, and B ₄ = 2, the slot allocator 11 determines that all B _{1 to} B ₄ are not 0 in step S203 shown in FIG. Since I / B ₁ = 10/2 = 5, I / B ₂ = 10/2 = 5, and I / B ₄ = 10/2 = 5 in step S205, the condition (2) is satisfied, and step S206 is satisfied. The number of multiplexed frames N = 5 is determined by the above process.

  FIG. 3 is a diagram illustrating a configuration example (1) of a multiplex frame and a super frame. This multiplex frame and superframe have a multiplex frame number N = 5, a TS1 allocation slot number 4.2, a TS2 allocation slot number 2.2, a TS3 allocation slot number 2.0, and a TS4 allocation slot number 0.2. At this time, the frame is generated by the multiplexing unit 13. In the superframe, TS1 is stored in 21 slots (number of assigned slots 4.2 × 5 multiplexed frames 5), TS2 is stored in 11 (2.2 × 5) slots, and TS3 is 10 ( 2.0 × 5) and TS4 is stored in one (0.2 × 5) slot. Note that the position of the slot in which each TS is stored does not necessarily have to be the arrangement shown in FIG. 3 as long as the number of TSs stored in the superframe and the number of empty slots are the same. Such an arrangement may be used. The same applies to FIG.

  As described above, the multiplexing unit 13 generates the multiplexed frame and the super frame shown in FIG. 3, and the number of multiplexed frames constituting the super frame is N = 5. Compared to the technology of No. 4, the size of the super frame is halved. Accordingly, the time required for establishing synchronization of the super frame can be shortened in the separation apparatus that receives the super frame and will be described later.

  FIG. 4 is a diagram illustrating a configuration example of a multiple frame header. This multiplex frame header has a multiplex frame number N = 5, a TS1 allocation slot number of 4.2, a TS2 allocation slot number of 2.2, a TS3 allocation slot number of 2.0, and a TS4 allocation slot number of 0.2. The header is generated by the header generator 12.

  As shown in FIG. 4, the multiplex frame header includes packet synchronization information, multiplex frame synchronization information, slot allocation information, position information, update information, and other information. The packet synchronization information (0x47) is information indicating the head of data in the TS packet format, and the multiplex frame synchronization information (0x1a86, 0x0579) is information for establishing synchronization of multiplex frames. This multi-frame synchronization information is stored in ITU-T Rec. J. et al. Similar to the provisions of H.183, it consists of two types of information in which all bits are inverted for each multiplexed frame.

  Similar to Non-Patent Document 3 described above, the slot allocation information is represented by using a 4-bit relative TS_id, and includes 15 TS_ids (TS IDs), a correspondence table of original_network_id and relative TS_id, and a table of relative TS_id. Composed. These two tables specify the TS packet stored in each slot. Note that TS_id and original_network_id corresponding to the unassigned relative TS_id are 0xFFFF, and the relative TS_id of the empty slot is 0x0. This slot allocation information corresponds to TS1 to TS4 and empty slots stored in each multiplexed frame constituting the superframe shown in FIG. For example, it can be seen from FIG. 3 that 5 TS1, 3 TS2, 2 TS3, and 1 TS4 are stored in this order in the data slot of the first multiplexed frame. Referring to FIG. 4, in the first multiple frame header (header 1) corresponding to this, the correspondence table of relative TS_id of the slot allocation information is 5 0x1, 3 0x2, 2 0x3 and 1 It can be seen that this is in the order of 0x4, corresponding to FIG.

  The position information is information indicating a relative position of multiple frames (in the multiple frame header) constituting the super frame. The position information has a bit number of 4 and is assigned numbers 1 to 5 in the order of transmission of multiple frames (multiple frame headers). If the transmission order does not change, the assignment may be started from any header. In the above example, since the maximum value of the multiplexed frame is I = 10, the position information takes a value from 1 to 10, and takes a maximum value of 10. Therefore, the number of bits of the position information is 4 bits (= 16) It is enough. The update information is update information indicating whether the slot allocation information has changed. In the update information, the number of bits is 8, and 1 is added when there is a change in the position information. When the maximum value (255) is reached, the result of adding 1 is set to 0.

(Embodiment 2: When the number of multiplexed frames N is determined by the above (1), N = 1)
Next, as another embodiment of the multiplexing apparatus 1 shown in FIG. 1, in the rule for determining the number N of multiplexed frames, when the condition (1) is satisfied (the number of multiplexed frames N = 1 by the slot allocation unit 11). An example in which is determined) will be described. The number of TSs input by the multiplexing apparatus 1 is J = 4, and the normalization speeds are TS1 = 4, TS2 = 2, TS3 = 2, and TS4 = 1 for each TS input by the multiplexing apparatus 1 (TS1). , TS2 and TS4 are different from the transmission speed of the first embodiment), and the multiplexed frame is composed of a slot for storing 11 data and a slot for storing one header. The maximum value I = 10.

Slot allocation unit 11 based on the normalized speed TS1 = 4, TS2 = 2, TS3 = 2, TS4 = 1 is the speed information 1 to J, assigned slot number _A 1 ₊ B 1 / _{10~A 4} of each TS determining + _B 4/10. That is, the number of assigned slots of TS1 is 4.0 (= 4 + 0/10), the number of assigned slots of TS2 is 2.0 (= 2 + 0/10), the number of assigned slots of TS3 is 2.0 (= 2 + 0/10), The number of slots allocated to TS4 is 1.0 (= 1 + 0/10), A ₁ = 4, B ₁ = 0, A ₂ = 2, B ₂ = 0, A ₃ = 2, B ₃ = 0, A ₄ = 1, B ₄ = 0.

Since the determined parameters B ₁ = 0, B ₂ = 0, B ₃ = 0, and B ₄ = 0, all the B _{1 to} B ₄ are 0 in step S203 shown in FIG. The number of multiplexed frames N = 1 is determined by satisfying the condition (1) and performing the processing in step S204 described above.

  FIG. 5 is a diagram illustrating a configuration example (2) of the multiplex frame and the super frame. The multiplex frame and superframe have a multiplex frame number N = 1, a TS1 allocation slot number of 4.0, a TS2 allocation slot number of 2.0, a TS3 allocation slot number of 2.0, and a TS4 allocation slot number of 1.0. At this time, the frame is generated by the multiplexing unit 13. In the superframe, TS1 is stored in 4 slots (number of assigned slots 4.0 × multiple frame number 1), TS2 is stored in 2 (2.0 × 1) slots, and TS3 is 2 ( 2.0 × 1) and TS4 is stored in one (1.0 × 1) slot.

  As described above, the multiplexing unit 13 generates the multiplexed frame and the super frame shown in FIG. 5, and the number of multiplexed frames constituting the super frame is N = 1. Compared to the technology of No. 4, the size of the super frame is 1/10. Accordingly, the time required for establishing synchronization of the super frame can be shortened in the separation apparatus that receives the super frame and will be described later.

(Third embodiment: N = 10 when the number N of multiplexed frames is determined by the above (3))
Next, as another embodiment of the multiplexing apparatus 1 shown in FIG. 1, in the rule for determining the number N of multiplexed frames, when the condition (3) is satisfied (the number of multiplexed frames N = 10 by the slot allocation unit 11). An example in which is determined) will be described. The number of TSs input by the multiplexer 1 is J = 4, and for each TS input by the multiplexer 1, the normalized speeds are TS1 = 4.134, TS2 = 2.198, TS3 = 2, TS4 = 0.221 (only the transmission rate of TS4 is different from that of the first embodiment), and the multiplex frame is composed of a slot for storing 11 data and a slot for storing one header. It is assumed that the maximum value I = 10 of the multiplex frames constituting the.

The slot allocation unit 11 assigns the number of slots allocated to each TS based on the normalized speeds TS1 = 4.134..., TS2 = 2.198..., TS3 = 2, TS4 = 0.212. determining _{a 1 + B 1 / 10~A 4} + B 4/10. That is, the number of assigned slots for TS1 is 4.2 (= 4 + 2/10), the number of assigned slots for TS2 is 2.2 (= 2 + 2/10), the number of assigned slots for TS3 is 2.0 (= 2 + 0/10), The number of slots assigned to TS4 is 0.3 (= 0 + 3/10), A ₁ = 4, B ₁ = 2, A ₂ = 2, B ₂ = 2, A ₃ = 2 and B ₃ = 0, A ₄ = 0, B ₄ = 3 (only B ₄ is different from the first embodiment).

From the determined parameters B ₁ = 2, B ₂ = 2, B ₃ = 0, and B ₄ = 3, the slot allocating unit 11 determines that all B _{1 to} B ₄ are not 0 in step S203 shown in FIG. Since I / B ₄ = 10/3 is not an integer in step S205, the condition (3) is satisfied, and the number of multiplexed frames N = I = 10 is determined by the processing in step S207.

  FIG. 6 is a diagram illustrating a configuration example (3) of a multiplex frame and a super frame. This multiplex frame and superframe have a multiplex frame number N = 10, a TS1 allocation slot number of 4.2, a TS2 allocation slot number of 2.2, a TS3 allocation slot number of 2.0, and a TS4 allocation slot number of 0.3. At this time, the frame is generated by the multiplexing unit 13. In the superframe, TS1 is stored in 42 slots (number of assigned slots 4.2 × 10 multiplexed frames 10), TS2 is stored in 22 (2.2 × 10) slots, and TS3 is 20 ( 2.0 × 10) slots, and TS4 is stored in three (0.3 × 10) slots.

  As described above, according to the multiplexing apparatus 1 according to the embodiment of the present invention, the time slot of the transmission path is fixedly assigned to a plurality of TSs, time-division multiplexed, and a multiplexed frame and a super frame are configured. In the transmission system, when the slot allocation unit 11 determines the number of allocated slots based on the speed information 1 to J of TS1 to TSJ, the speed of each TS1 to TSJ is equal to or higher than the original speed, and the speed conversion is performed. The number of multiplexed frames and the slot allocation information are determined so that null packets inserted at times are minimized. The header generation unit 12 generates position information and update information based on the number of multiplexed frames and slot allocation information, and generates a multiplexed frame header. Further, the multiplexing unit 13 inputs TS1 to TSJ converted in speed by the speed converting units 10-1 to 10-J, and stores and multiplexes TS1 to TSJ in data slots based on the slot allocation information. Multiple frame headers are stored in header slots, and multiple frames and super frames are generated and output.

  Thereby, since the super frame is composed of an appropriate number of multiplexed frames based on the speed information 1 to J of TS1 to TSJ, the size of the superframe can be reduced. Moreover, since the null packet inserted into TS becomes the minimum, the speed conversion of each TS can be performed appropriately. Accordingly, it is possible to suppress a decrease in transmission efficiency and to shorten the time required for establishing superframe synchronization in the separation apparatus described later. Furthermore, by appropriately setting the speed after conversion for each TS, the size of the super frame can be reduced, etc., and it is possible to respond flexibly according to conditions required for transmission efficiency and synchronization establishment time. Can do.

[Separator]
Next, the separation apparatus according to the embodiment of the present invention will be described. FIG. 7 is a block diagram showing the configuration of the separation apparatus. The separation device 2 includes a synchronization establishment unit 20, a slot allocation information acquisition unit 21, and a separation unit 22. The demultiplexer 2 inputs the superframe output from the multiplexer 1 via the transmission line, establishes the synchronization of the multiframe, establishes the synchronization of the superframe, and extracts the slot allocation information from the multiframe header Then, based on the slot allocation information, the requested TS is separated from the superframe and output.

  When the synchronization establishing unit 20 receives a super frame and determines that the update information in the multiplexed frame header has not changed, the synchronization establishing unit 20 establishes only the synchronization of the multiplexed frame, assuming that the slot allocation information has not changed. Further, when it is determined that the update information has changed, the synchronization establishment unit 20 determines that there is a change in the slot allocation information and establishes synchronization of multiple frames and superframes. Then, when only the synchronization of the multiplex frame is established, the synchronization establishment unit 20 outputs the synchronization information indicating the head of the multiplex frame and the position information of the multiplex frame to the slot allocation information acquisition unit 21. In addition, the synchronization establishing unit 20 sets the synchronization information indicating the head of the super frame (for example, the head of the multiplexed frame whose position information is 1) and the number of multiplexed frames when the synchronization of the multiplexed frame and the super frame is established. Output to the acquisition unit 21. Details of the synchronization establishing unit 20 will be described later.

  The slot allocation information acquisition unit 21 receives a super frame, and also receives synchronization information and the number of multiplexed frames indicating the head of the super frame, or synchronization information and position information indicating the head of the multiplexed frame from the synchronization establishing unit 20. The slot allocation information acquisition unit 21 acquires new slot allocation information from the multiplex frame header of the multiplex frame constituting the super frame when the synchronization information indicating the head of the super frame and the number of multiplex frames are input. Output. The slot allocation information acquisition unit 21 stores the slot allocation information (slot allocation information of the multiplex frame indicated by the position information) that has already been acquired when the synchronization information and the position information indicating the head of the multiplex frame are input. (Not shown) and output to the separation unit 22. Details of the slot allocation information acquisition unit 21 will be described later.

  The separation unit 22 receives a superframe, receives slot assignment information from the slot assignment information acquisition unit 21, and receives identification information (TS_id (ID of TS) and original_network_id (original network) of the TS requested to be separated by the separation device 2). ID)). Then, the separation unit 22 separates and outputs the requested TS from the multiplexed frames constituting the superframe based on the slot allocation information.

(Synchronization establishment part)
Next, the synchronization establishment unit 20 shown in FIG. 7 will be described in detail. As described above, when the synchronization establishment unit 20 receives a superframe and determines that the update information in the multiplex frame header has not changed, the synchronization establishment unit 20 establishes only the multiplex frame synchronization, assuming that there is no change in the slot allocation information. . Further, when it is determined that the update information has changed, the synchronization establishment unit 20 determines that there is a change in the slot allocation information and establishes synchronization of multiple frames and superframes.

  FIG. 8 is a flowchart showing the processing of the synchronization establishing unit 20. The synchronization establishment unit 20 includes storage means (not shown) for storing update information (update information for each multiplex frame) acquired from the multiplex frame header, establishes synchronization between the multiplex frame and the superframe, and has already been updated. It is assumed that information is stored. The synchronization establishing unit 20 inputs a super frame (step S801), acquires position information and update information from the multiplexed frame header of the multiplexed frames constituting the input super frame (step S802), and reads the updated information from the storage unit. (Step S803).

  The synchronization establishment unit 20 compares the acquired update information with the read update information for each multiplex frame (step S804), and when it is determined that the update information is the same (step S804: Y), By determining that there is no change and acquiring the pattern of the multiplexed frame synchronization information, the synchronization of the multiplexed frame is established (step S805). Then, the synchronization establishing unit 20 outputs the synchronization information indicating the head of the multiplexed frame and the position information of the multiplexed frame to the slot allocation information acquiring unit 21 (step S806). As described above, since the update information is information indicating whether or not the slot allocation information has changed, if the acquired update information is the same as the read update information, the slot allocation information has not changed. Become. On the other hand, if the update information is not the same, the slot allocation information has changed, so it is necessary to acquire new slot allocation information from the multiplex frame header.

  On the other hand, if the synchronization establishment unit 20 determines in step S804 that the update information is not the same (step S804: N), the synchronization establishment unit 20 establishes the synchronization of the multiple frames by obtaining the pattern of the multiple frame synchronization information (step S807). ). Then, the synchronization establishment unit 20 establishes superframe synchronization based on the position information in the multiplex frame header (step S808), and determines the number of multiplex frames (the number of multiplex frames) constituting the superframe (step 808). S809). As described above, the position information is information indicating the relative position of the multiple frames constituting the super frame, and numbers are assigned in the order of transmission of the multiple frames. Therefore, the largest number among the numbers indicated by the position information of the multiplexed frames constituting the superframe is the number of multiplexed frames.

  The synchronization establishing unit 20 stores the acquired update information (new update information) in the storage unit, and overwrites the already stored update information (step S810). Then, the synchronization establishment unit 20 outputs the synchronization information indicating the head of the super frame and the number of multiplexed frames to the slot allocation information acquisition unit 21 (step S811).

  As described above, when it is determined that the update information has not changed, the synchronization establishment unit 20 determines that there is no change in the slot assignment information and establishes only the synchronization of the multiple frames by acquiring the pattern of the multiple frame synchronization information. The synchronization information indicating the head of the multiplex frame and the position information of the multiplex frame are output to the slot allocation information acquisition unit 21. Also, if the synchronization establishment unit 20 determines that the update information has changed, the synchronization establishment unit 20 determines that the slot allocation information has changed, establishes synchronization of the multiplex frame, and based on the position information in the multiplex frame header, Synchronization is established, the number of multiplexed frames is set, the synchronization information indicating the head of the superframe and the number of multiplexed frames are output to the slot allocation information acquiring unit 21, and the slot allocation information acquiring unit 21 acquires new slot allocation information .

(Slot allocation information acquisition unit)
Next, the slot allocation information acquisition unit 21 shown in FIG. 7 will be described in detail. As described above, when the synchronization information indicating the head of the super frame and the number of multiplexed frames are input from the synchronization establishing unit 20, the slot allocation information acquiring unit 21 acquires new slot allocation information from the multiplexed frame header in the super frame. To do. Further, when the synchronization information indicating the head of the multiplexed frame and the position information are input from the synchronization establishing unit 20, the slot allocation information acquiring unit 21 has already acquired the slot allocation information without acquiring the slot allocation information from the multiplexed frame header in the superframe. The assigned slot assignment information (slot assignment information of the multiplexed frame indicated by the position information) is read from the storage means (not shown).

  FIG. 9 is a flowchart showing the processing of the slot allocation information acquisition unit 21. The slot allocation information acquisition unit 21 includes storage means (not shown) for storing slot allocation information and position information (slot allocation information and position information for each multiplex frame) acquired from the multiplex frame header. And position information is already stored.

  The slot allocation information acquisition unit 21 inputs a super frame (step S901), and determines whether or not synchronization information indicating the head of the super frame and the number of multiplexed frames are input from the synchronization establishment unit 20 (step S902).

  If the slot allocation information acquisition unit 21 determines in step S902 that the synchronization information indicating the head of the super frame and the number of multiplexed frames have been input (step S902: Y), the slot allocation information acquisition unit 21 is based on the synchronization information indicating the head of the super frame. Recognizing the super frame, for the multiple frames corresponding to the number of multiple frames constituting the super frame, the slot allocation information and the position information for all the multiple frames are acquired from the multiple frame header and stored in the storage means (step S903). In this case, the slot allocation information and position information that have already been stored are discarded. Then, the slot allocation information acquisition unit 21 outputs the acquired slot allocation information for all multiplexed frames to the separation unit 22 (step S904).

  On the other hand, if the slot allocation information acquisition unit 21 determines in step S902 that the synchronization information indicating the head of the super frame and the number of multiplexed frames are not input (step S902: N), It is determined whether or not synchronization information and position information indicating the head of the frame have been input (step S905).

  If the slot allocation information acquisition unit 21 determines in step S905 that the synchronization information and position information indicating the head of the multiplexed frame have been input (step S905: Y), the slot allocation information acquisition unit 21 sets the synchronization information and position information indicating the head of the multiplexed frame. Based on this, the multiplex frame indicated by the position information is recognized, and the slot assignment information is read out from the storage means using the inputted position information as a key without acquiring the slot assignment information from the multiplex frame header (step S906). Then, the slot allocation information acquisition unit 21 outputs the read slot allocation information to the separation unit 22 (step S907). On the other hand, when it is determined in step S905 that the synchronization information indicating the head of the multiplexed frame and the position information are not input (step S905: N), the slot allocation information acquisition unit 21 performs an abnormality process.

  As described above, when the synchronization information indicating the head of the super frame and the number of multiplexed frames are input from the synchronization establishing unit 20, the slot allocation information acquiring unit 21 acquires the slot allocation information from the multiplexed frame header in the super frame. Further, when the slot allocation information acquisition unit 21 receives the synchronization information and the position information indicating the head of the multiplex frame from the synchronization establishment unit 20, the slot allocation information acquisition unit 21 has already acquired the slot allocation information without acquiring the slot allocation information from the multiplex frame header in the superframe. The assigned slot allocation information is read from the storage means.

〔Concrete example〕
Next, a specific example of processing for establishing synchronization of multiple frames and superframes and processing for acquiring slot allocation information will be described. It is assumed that the super frame shown in FIG. 3 is input to the separation device 2, and the multiplex frame header shown in FIG. 4 is added to the multiplex frame. In addition, the number of backward protection stages for multiframe synchronization and superframe synchronization in the synchronization establishing unit 20 is assumed to be 3, and there is no forward protection.

(Example 4: When update information changes)
First, a case where update information changes (when slot allocation information changes) will be described. For example, it is assumed that update information 0x7 is stored in the storage unit of the synchronization establishing unit 20, and the synchronization establishing unit 20 acquires the update information 0x8 from the multiplexed frame header in the superframe.

  The synchronization establishment unit 20 compares the update information 0x8 obtained from the multiple frame header with the update information 0x7 read from the storage means, determines that the update information is not the same, and establishes synchronization of the multiple frame and the super frame. To do. Specifically, the synchronization establishing unit 20 determines (establishes) the start position of the multiplexed frame by determining that the pattern of the multiplexed frame synchronization information (0x1a86, 0x0579) has been received three times in succession at the correct timing. To do. Thereby, the synchronization of multiple frames is established. Then, the synchronization establishing unit 20 acquires position information from the multiplex frame header, and determines that a value of 1 to 5 has been received for three consecutive periods, whereby a super frame is configured by five multiplex frames. And determines (establishes) the head of the multiplexed frame whose position information is 1 as the head position of the super frame. This establishes superframe synchronization.

  The synchronization establishment unit 20 overwrites the update information 0x8 newly stored in the update information 0x7 stored in the storage unit. Then, the synchronization establishment unit 20 outputs the synchronization information (synchronization information indicating the head) reflecting the head position of the superframe and the number of multiplexed frames 5 to the slot allocation information acquisition unit 21.

  The slot allocation information acquisition unit 21 receives the synchronization information indicating the head of the super frame and the number of multiplexed frames 5 from the synchronization establishment unit 20, and the update information has changed, and it is necessary to acquire new slot allocation information. It is determined that there are five types of multiple frames in the superframe. The slot allocation information acquisition unit 21 recognizes a super frame based on synchronization information indicating the head of the super frame, and acquires slot allocation information and position information for five multiplexed frames from the multiplexed frame header in the super frame. The slot allocation information and position information stored in the storage means are discarded, and the acquired slot assignment information and position information are stored in the storage means. Then, the slot allocation information acquisition unit 21 outputs the acquired slot allocation information to the separation unit 22.

(Example 5: When update information has not changed)
Next, a case where update information has not changed (a case where slot allocation information has not changed) will be described. For example, it is assumed that the update information 0x8 is stored in the storage unit of the synchronization establishing unit 20, and the synchronization establishing unit 20 acquires the update information 0x8 from the multiplexed frame header in the superframe.

  The synchronization establishment unit 20 compares the update information 0x8 obtained from the multiplex frame header with the update information 0x8 read from the storage means, determines that the update information is the same, and establishes only the multiplex frame synchronization. Specifically, the synchronization establishing unit 20 determines (establishes) the start position of the multiplexed frame by determining that the pattern of the multiplexed frame synchronization information (0x1a86, 0x0579) has been received three times in succession at the correct timing. To do. Thereby, the synchronization of multiple frames is established. Then, the synchronization establishing unit 20 acquires position information from the multiplex frame header, and outputs synchronization information (synchronization information indicating the start) and position information reflecting the start position of the multiplex frame to the slot allocation information acquisition unit 21.

  The slot allocation information acquisition unit 21 receives the synchronization information indicating the head of the multiplexed frame and the position information from the synchronization establishment unit 20, so that the update information has not changed and it is not necessary to acquire new slot allocation information. Judge that. The slot allocation information acquisition unit 21 reads out slot allocation information corresponding to the same position information as the input position information from the storage unit, and outputs it to the separation unit 22.

  As described above, according to the separation device 2 according to the embodiment of the present invention, the slot of the TS is allocated from the multiplexing device 1 so that the TS is equal to or higher than the original speed and the null packet is minimized, When a super frame composed of a plurality of multiplex frames is input, the synchronization establishing unit 20 includes storage means for storing update information, and when the update information of the multiplex frame header in the super frame is changed, the multiplex frame In addition, when synchronization of superframes is established and update information is not changed, only synchronization of multiple frames is established. Further, the slot allocation information acquisition unit 21 includes storage means for storing the slot allocation information and the position information, and when the update information has not changed, without acquiring the slot allocation information from the multiplex frame header in the superframe, The slot allocation information is read from the storage means.

  Since the superframe input from the multiplexing apparatus 1 is composed of an appropriate number of multiplexed frames based on the speed information 1 to J of TS1 to TSJ, the size of the superframe is not a preset fixed size. Is getting smaller properly. Therefore, the separating apparatus 2 can shorten the time required for establishing synchronization of the superframe.

  Further, since the synchronization establishment unit 20 stores the acquired update information in the storage unit, and the slot allocation information acquisition unit 21 stores the acquired slot allocation information and position information in the storage unit, the synchronization establishment unit 20 Thereafter, as long as there is no change in the update information of the multiplexed frame header in the input superframe, the separation unit 22 performs the same slot assignment as before stored in the storage means by performing only the process of establishing the synchronization of the multiplexed frame. Information can be used to separate TSs. In other words, TS separation processing is performed only by establishing synchronization of multiple frames without establishing superframe synchronization. Even if the demultiplexing device 2 receives the slot allocation information in a certain multiplex frame by mistake, the TS can be demultiplexed using the same slot allocation information as previously stored in the storage means. Therefore, the time required for establishing synchronization for TS separation processing can be shortened as compared with the prior art in which TS separation processing is performed after superframe synchronization is established in addition to establishment of synchronization of multiple frames.

  In the above-described fourth and fifth embodiments, when the update information has changed and when the update information has not changed, the information in the multiplexed frame header is acquired from the state where the synchronization of the multiplexed frame is not established. Compare the required time between. The time required to establish synchronization of multiple frames is multiple frame length × 3, and the time required to establish synchronization of superframes is superframe length × 3. Therefore, the required time when the update information is changed is a time obtained by adding the time required for establishing synchronization of multiple frames and the time required for establishing synchronization of superframes. On the other hand, the time required when the update information has not changed is equal to the time required to establish synchronization of multiple frames. As a result, when the update information has not changed, the time required for establishing synchronization for acquiring information in the multiframe header and performing TS separation processing is the time required for establishing superframe synchronization. It can be shortened by the time of frame length × 3.

[Modification 1]
Next, a first modified example (modified example 1) in the multiplexing apparatus 1 shown in FIG. 1 will be described. Modification 1 is a process for determining the number of multiplexed frames when the condition (3) is satisfied among the conditions (1) to (3) described above (when the number of multiplexed frames is determined to be the maximum value I). The parameters A and B are forcibly changed so as to satisfy the condition (1) or (2). That is, in order to reduce the number of multiplexed frames, processing is performed so that the maximum value I is not determined.

The multiplexing device 1 of the first modification includes a slot allocation unit 11 that performs processing different from the processing described above. In the processing flow shown in FIG. 2, the slot allocation unit 11, the determination in step S205, is not the integer all I / B _j for B _j is not zero, i.e., with any of the I / B _j is not an integer If so (step S205: N), the number of multiple frames is determined as the maximum value I (step S207). On the other hand, instead of the process of step S207, the slot allocation unit 11 of the modification 1 determines A _j and B _j for setting all B _j to 0, performs the process of step S204, and performs the superframe. The number of multiplexed frames is determined as 1. _{Alternatively} , A _j and B _j for making non-integer I / B _j an integer are determined, and the process of step S206 is performed using the new I / B _j, and the number of multiplexed frames is set to LCM {I / B _j }. (The least common multiple of I / B _j ).

As described above, according to the multiplexing apparatus 1 of the first modification, for TSj having I / B _j that is not an integer, the transmission efficiency is reduced along with the speed conversion by the speed conversion unit 10-j, Since the number of multiplex frames to be configured is reduced, the size of the super frame can be reduced, and the time required for establishing synchronization of the super frame can be shortened. Therefore, it can be applied flexibly according to conditions required for transmission efficiency and synchronization establishment time.

For example, in Example 3 described above, the number of slots allocated to TS1 (normalized speed after speed conversion) is 4.2 (= 4 + 2/10), the number of slots allocated to TS2 is 2.2 (= 2 + 2/10), The number of slots allocated to TS3 is 2.0 (= 2 + 0/10), the number of slots allocated to TS4 is 0.3 (= 0 + 3/10), and A ₁ = 4, B ₁ = 2 and A ₂ = 2, B ₂ = 2, A ₃ = 2, B ₃ = 0, A ₄ = 0, B ₄ = 3. Since I / B ₄ = 10/3 is not an integer in step S205, the condition (3) is satisfied, and the number of multiplexed frames is determined to be 10 (maximum value I) by the process in step S207.

On the other hand, in the first modification, the number of assigned slots of TS4 is set to 1.0 instead of 0.3, that is, A ₄ = 1 and B ₄ = 0 instead of A ₄ = 0 and B ₄ = 3. Thus, the condition (2) is satisfied, and the number of multiplexed frames is determined to be 5. That is, by changing the normalized speed 0.3 after the speed conversion of TS4 to 1.0, the condition (2) is satisfied, and the number of multiplexed frames is determined to be 5. In this case, the time required for establishing synchronization of the superframe can be shortened by allowing a decrease in transmission efficiency accompanying the speed conversion of TS4.

[Modification 2]
Next, a second modification (modification 2) of the multiplexing apparatus 1 shown in FIG. 1 will be described. In Modification 2, in the process of determining the number of multiplexed frames, among the conditions (1) to (3) described above, the condition (3) (all I / B _j for non-zero B _j is not an integer) That is, the condition of (2) (all I / B _{1 to} I / B _J are integers for non-zero B _{1 to} B _J ) without satisfying any I / B _j is not an integer) is satisfied. A maximum value I of the number of multiplexed frames is set in advance so as to satisfy. That is, processing is performed so as to reduce the probability that the number of multiplexed frames is determined to be the maximum value I and increase the probability that the number of multiplexed frames is determined to be 1 to I-1.

Specifically, the slot allocation unit 11 performs processing using the maximum value I of the number of multiplexed frames shown below. A unit (1 / I slot) for allocating a slot in a multiplexed frame can be freely set within a range in which the maximum value I of the number of multiplexed frames is a positive integer other than a prime number. That is, the maximum value I of the number of multiplexed frames is set to a value having more prime factors. When the maximum value I of the number of multiplexed frames is set to a prime number, the integer 1 is obtained when I / B _j is B _j = I, but it is not an integer otherwise. In this case, the probability that I / B _j becomes an integer is lower than when the maximum value I of the number of multiplexed frames is set to a value other than a prime number (a value having more prime factors), and the condition of (3) is satisfied. The probability of satisfying increases. Accordingly, by setting the maximum value I of the number of multiplexed frames to a value having a larger prime factor, among the conditions (1) to (3) for determining the number of multiplexed frames in the superframe, (2) The probability of satisfying the condition (3) is high, and the probability of satisfying the condition (3) is low. That is, the size of the super frame can be reduced, and the time required for establishing synchronization of the super frame can be shortened.

  As a hardware configuration of the multiplexing device 1 and the demultiplexing device 2 according to the embodiment of the present invention, a normal computer can be used. The multiplexing device 1 and the separation device 2 are configured by a computer including a CPU, a volatile storage medium such as a RAM, a non-volatile storage medium such as a ROM, an interface, and the like. The functions of the speed conversion units 10-1 to 10-J, the slot allocation unit 11, the header generation unit 12, and the multiplexing unit 13 included in the multiplexing apparatus 1 cause the CPU to execute a program describing these functions. It is realized by each. The functions of the synchronization establishment unit 20, the slot allocation information acquisition unit 21, and the separation unit 22 included in the separation device 2 are also realized by causing the CPU to execute a program describing these functions. These programs can be stored and distributed in a storage medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, or the like.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the technical idea thereof.

DESCRIPTION OF SYMBOLS 1 Multiplexer 2 Separation apparatus 10-1 to 10-J Speed conversion unit 11 Slot allocation unit 12 Header generation unit 13 Multiplexing unit 20 Synchronization establishment unit 21 Slot allocation information acquisition unit 22 Separation unit

Claims (12)

Multiplexed transmission slots are fixedly assigned to a plurality of transport streams, the transport streams are time-division multiplexed, a superframe consisting of one or more multiplexed frames is generated and output to the transmission path In the device
Based on the speed of the plurality of transport streams, the number of multiplexed frames constituting the super frame is determined, and each of the transport streams when storing the plurality of transport streams in the data slot of the multiplexed frame A slot allocation unit for generating slot allocation information in which the number and position of slots to be allocated are defined;
A speed conversion unit that converts the speed of the transport stream based on the slot allocation information;
A header generation unit for generating a multi-frame header including the slot allocation information;
Based on the slot assignment information, the rate-converted transport stream is stored in the data slot of the multiplexed frame and multiplexed, the multiplexed frame header is stored in the header slot of the multiplexed frame, and the number of multiplexed frames A multiplexing unit that generates a superframe composed of multiple frames of
A multiplexing apparatus comprising: The multiplexing device according to claim 1, wherein
The speed conversion unit converts the speed by inserting a null packet into the transport stream,
The slot allocation unit determines the number of multiplexed frames so that a transport stream is not lost along with the multiplexing, and a null packet inserted at the time of the speed conversion is minimized, and the slot allocation is performed. A multiplexing apparatus that generates information. The multiplexing device according to claim 2, wherein
The number of transport streams is J (J is an integer), the maximum number of multiplexed frames is I (I is an integer), A and B are parameters (A is a positive integer, and B is a positive number less than I). ), When the transport stream is speed-converted to allocate slots in 1 / I slot units,
The slot allocation unit includes:
The number of slots A ₁ + B ₁ / I to be allocated to the J transport streams so that the transport stream is not lost with the multiplexing and the number of null packets inserted at the time of the speed conversion is minimized. Determine A _J + B _J / I respectively,
When B ₁ =... = B _J = 0 (1), the number of multiplexed frames is determined to be 1, and there is a non-zero B _j (j is a positive integer less than or equal to J), and all non-zero B _When I / B _j is an integer with respect to _j (2), the number of multiplexed frames is determined to be LCM {I / B _j } (LCM {} represents the least common multiple), and (1) and (2) When neither of the conditions is satisfied, the multiplexing apparatus determines the number of multiplexed frames as I. The multiplexing device according to claim 3, wherein
If the slot allocation unit does not satisfy either of the conditions (1) and (2), instead of determining the number of multiplexed frames as I, the slot allocation unit A satisfies the condition (1) or (2). And B are newly determined, and the number of multiplexed frames is determined to be LCM {I / B _j }. In the multiplexing apparatus as described in any one of Claim 1-4,
The header generation unit generates position information indicating a relative position of multiple frames constituting a super frame based on the slot assignment information, and generates a multiple frame header including the slot assignment information and the position information. A multiplexing device characterized by that. In the multiplexing apparatus as described in any one of Claim 1-5,
The header generation unit generates update information indicating whether the slot allocation information has changed based on the slot allocation information, and generates a multi-frame header including the slot allocation information and the update information; A multiplexing device characterized. A demultiplexer that inputs a superframe output by the multiplexing device according to claim 5 and demultiplexes a predetermined transport stream from the multiframe constituting the superframe,
Position information indicating the relative position of the multiple frame is established from the multiple frame header of the multiple frame constituting the super frame by establishing synchronization of the multiple frame constituting the super frame, establishing the synchronization of the super frame. A synchronization establishment unit that obtains and determines the number of multiplexed frames based on the position information;
A slot allocation information acquisition unit for acquiring slot allocation information for the number of multiplexed frames from a multiplexed frame header of the multiplexed frames constituting the superframe;
A separator that separates a predetermined transport stream from multiple frames constituting the superframe based on the slot allocation information;
A separation device comprising: A demultiplexer that inputs a superframe output by the multiplexing device according to claim 6 and demultiplexes a predetermined transport stream from the multiframe constituting the superframe,
When obtaining update information indicating whether or not the slot assignment information has changed from a multiplex frame header of a multiplex frame constituting the super frame, and when determining that the slot assignment information has changed from the update information, A synchronization establishment unit that establishes synchronization of multiple frames and synchronization of the super frame, and determines that slot assignment information has not changed from the update information; and
When synchronization of the multiplexed frame and synchronization of the superframe are established, slot allocation information corresponding to the number of multiplexed frames is obtained and output from the multiplexed frame header of the multiplexed frame constituting the superframe, and the multiplexed frame is output. Slot synchronization information acquisition unit for outputting the slot allocation information that has already been acquired,
A demultiplexing unit that demultiplexes a predetermined transport stream from multiple frames constituting the superframe based on the slot allocation information output by the slot allocation information acquisition unit;
A separation device comprising: Multiplexed transmission slots are fixedly assigned to a plurality of transport streams, the transport streams are time-division multiplexed, a superframe consisting of one or more multiplexed frames is generated and output to the transmission path In the conversion method,
Determining the number of multiplexed frames constituting the superframe based on the speeds of the plurality of transport streams;
Generating slot allocation information in which the number and position of slots allocated to each transport stream when the plurality of transport streams are stored in the data slots of the multiplex frame;
Converting the speed of the transport stream based on the slot allocation information;
Generating a multi-frame header including the slot allocation information;
Based on the slot allocation information, the speed-converted transport stream is stored and multiplexed in the data slot of the multiplexed frame, the multiplexed frame header is stored in the header slot of the multiplexed frame, and the number of multiplexed frames Generating a superframe consisting of multiple frames;
Outputting the superframe;
A multiplexing method characterized by comprising: According to the multiplexing method of claim 9, a plurality of transport streams are multiplexed and stored in a data slot, and slot allocation information in which the number and position of slots allocated to each transport stream is defined, and a multiplexed frame A multiplex frame header including position information indicating a relative position of the multiplex frame in the constituted super frame is stored in a header slot, and a super frame configured by the multiplex frame having the data slot and the header slot is input. A separation method for separating a predetermined transport stream from the multiplex frame,
Establishing synchronization of multiple frames making up the superframe;
Obtaining position information from multiple frame headers of multiple frames constituting the super frame, establishing synchronization of the super frame based on the position information, and determining the number of multiplexed frames;
Obtaining slot allocation information for the number of multiplexed frames from the multiplexed frame header of the multiplexed frames constituting the superframe;
Separating a predetermined transport stream from multiple frames constituting the superframe based on the slot allocation information;
A separation method characterized by comprising:   The multiplexing program for functioning a computer as a multiplexing apparatus as described in any one of Claim 1-6.   A separation program for causing a computer to function as the separation device according to claim 7 or 8.

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