Scrambling device and scrambling method

Abstract

To provide superior functionality related to transmitting scrambled signals.SOLUTION: A scrambling device includes a receiving unit that receives a non-scrambled signal, a PMT acquisition unit that acquires a first packet including a PMT from the non-scrambled signal, a scrambling unit that generates a scrambled signal using a scrambling key, a PMT generation unit that generates a second packet including a PMT that stores descriptor information related to the scrambling key, a multiplexing unit that multiplexes the second packet onto the scrambled signal, and a transmitting unit that transmits the scrambled signal onto which the second packet is multiplexed. The PMT generation unit adjusts the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a scrambling device and a scrambling method. [Background technology]

[0002] So-called retransmission services, which deliver broadcast content to subscribers' homes in real time, have become popular. For example, Patent Document 1 (JP 2020-10199 A) discloses the following IP retransmission device. That is, the IP retransmission device is used in an IP retransmission system that retransmits multi-channel digital broadcast signals received from an antenna to multiple receivers via an IP multicast network. The IP retransmission device extracts SI information from the digital broadcast signals, stores the SI information in packets with SI identification values added to part of the header information, and transmits the packets to the IP multicast network together with or separately from the broadcast stream. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-10199 Summary of the Invention [Problem to be solved by the invention]

[0004] In addition to retransmission services, independent broadcasting services that distribute content from independent broadcasting channels are becoming popular. In these independent broadcasting services, content is encrypted, a scrambled signal is generated, and the signal is transmitted to a receiver in the user's home. Regarding the transmission of the scrambled signal, a technology that can achieve superior functionality beyond that of the technology described in Patent Document 1 is desired.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a scrambling device and a scrambling method that can achieve excellent functions related to the transmission of scrambled signals. [Means for solving the problem]

[0006] The scrambling device of the present disclosure comprises a receiving unit that receives a non-scrambled signal containing content, a PMT acquisition unit that acquires a first packet containing a PMT (Program Map Table) from the non-scrambled signal received by the receiving unit, a scrambling unit that generates a scrambled signal by encrypting the non-scrambled signal using a scrambling key, a PMT generation unit that generates a second packet containing a PMT that stores descriptor information related to the scrambling key, a multiplexing unit that multiplexes the second packet generated by the PMT generation unit onto the scrambled signal generated by the scrambling unit, and a transmitting unit that transmits the scrambled signal onto which the second packet is multiplexed by the multiplexing unit, and the PMT generation unit adjusts the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet acquired by the PMT acquisition unit.

[0007] One aspect of the present disclosure can be realized not only as a scrambling device having such a characteristic processing unit, but also as a program for causing a computer to execute the steps of such a characteristic processing. Furthermore, one aspect of the present disclosure can be realized as a semiconductor integrated circuit that realizes part or all of the scrambling device, or as a system including the scrambling device. [Effects of the Invention]

[0008] According to the present disclosure, excellent functionality regarding the transmission of scrambled signals can be achieved. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram illustrating a configuration of a broadcasting system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating a configuration of a scrambling device according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a diagram illustrating an example of a signal transmitted and received by a scrambling device according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram showing an example of transition of the version number of the PMT included in a signal transmitted and received by a scrambling device according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram showing an example of transition of the version number of the PMT included in a signal transmitted and received by a scrambling device according to a comparative example. [Figure 6] FIG. 6 is a diagram showing an example of transition of the version number of the PMT included in a signal transmitted and received by a scrambling device according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a flowchart defining an example of an operation procedure when a scrambling device according to an embodiment of the present disclosure transmits a scrambled signal. [Figure 8] FIG. 8 is a flowchart defining an example of an operation procedure when the scrambling device according to the embodiment of the present disclosure acquires the PMT packet Ppmt1. [Figure 9] FIG. 9 is a flowchart defining an example of an operation procedure when a scrambling device according to an embodiment of the present disclosure generates a PMT packet Ppmt2. [Figure 10] FIG. 10 is a diagram showing an example of transition of the version number of the PMT included in a signal transmitted and received by a scrambling device according to a modified example of an embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram showing an example of transition of the version number of the PMT included in a signal transmitted and received by a scrambling device according to a modified example of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] First, the contents of the embodiments of the present disclosure will be listed and described. (1) A scrambling device according to an embodiment of the present disclosure includes a receiving unit that receives a non-scrambled signal containing content, a PMT acquisition unit that acquires a first packet containing a PMT from the non-scrambled signal received by the receiving unit, a scrambling unit that generates a scrambled signal by encrypting the non-scrambled signal using a scrambling key, a PMT generation unit that generates a second packet containing a PMT that stores descriptor information related to the scrambling key, a multiplexing unit that multiplexes the second packet generated by the PMT generation unit onto the scrambled signal generated by the scrambling unit, and a transmitting unit that transmits the scrambled signal onto which the second packet is multiplexed by the multiplexing unit, and the PMT generation unit adjusts the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet acquired by the PMT acquisition unit.

[0011] In this way, by adjusting the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet, the version number of the PMT to be transmitted can be changed in accordance with the version number of the PMT included in the non-scrambled signal, allowing the PMT to be transmitted in accordance with the standard defined by ARIB (Association of Radio Industries and Businesses), thereby achieving excellent functionality for transmitting scrambled signals.

[0012] (2) In the above (1), the transmitting unit may be capable of switching the signal to be transmitted from the scrambled signal to the non-scrambled signal, and the PMT generating unit may adjust the version number of the PMT included in the second packet so that the interval between the version number of the PMT included in the first packet and the version number of the PMT included in the second packet is 2 or more.

[0013] With this configuration, even if the transmission signal switches from a scrambled signal to a non-scrambled signal between the time when the version number of the PMT contained in the received non-scrambled signal is changed and the time when the version number of the PMT multiplexed onto the scrambled signal is changed, the version number of the PMT sent by the scrambling device will be different before and after the time when the transmission signal is switched, so the PMT can be sent in accordance with the standards set by ARIB.

[0014] (3) In the above (1) or (2), the PMT generation unit may generate the second packet by adding the descriptor information to the PMT included in the first packet acquired by the PMT acquisition unit.

[0015] With this configuration, the second packet can be generated through simple processing using the PMT included in the received non-scrambled signal.

[0016] (4) In (3) above, the PMT acquisition unit may repeatedly acquire the first packet, the PMT generation unit may repeatedly generate the second packet, and the PMT generation unit may increment the version number of the PMT included in the second packet each time at least one of the PMT and the descriptor information included in the first packet is updated.

[0017] With this configuration, the version number can be changed with simple processing every time the data included in the PMT is updated.

[0018] (5) A scrambling method according to an embodiment of the present disclosure is a scrambling method in a scrambling device, and includes the steps of receiving a non-scrambled signal containing content, obtaining a first packet containing a PMT from the received non-scrambled signal, generating a scrambled signal by encrypting the non-scrambled signal using a scrambling key, generating a second packet containing a PMT in which descriptor information related to the scrambling key is stored, multiplexing the generated second packet onto the generated scrambled signal, and transmitting the scrambled signal multiplexed with the second packet, wherein in the step of generating the second packet, the version number of the PMT contained in the second packet is adjusted based on the version number of the PMT contained in the obtained first packet.

[0019] In this way, by adjusting the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet, the version number of the PMT to be transmitted can be changed to match the version number of the PMT included in the non-scrambled signal, allowing the PMT to be transmitted in accordance with the standard defined by ARIB, thereby achieving excellent functionality for transmitting scrambled signals.

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any manner.

[0021] [Configuration and basic operation] 1 is a diagram illustrating a configuration of a broadcasting system according to an embodiment of the present disclosure. Referring to FIG. 1, a broadcasting system 401 includes an encoding device 111, remuxing devices 121 and 221, a scrambling device 101, transmitting devices 131 and 231, and a control device 141. The encoding device 111, the remuxing devices 121 and 221, the scrambling device 101, the transmitting devices 131 and 231, and the control device 141 are provided in a cable television station building 301. Note that the broadcasting system 401 may be configured to include multiple pairs of remuxing devices 221 and transmitting devices 231.

[0022] A broadcasting system 401 transmits content to a set-top box (STB) 351 installed in a user's home via a cable television (CATV) network 321. The content includes, for example, audio information, video information, program specific information (PSI), and service information (SI).

[0023] The content includes PSI information such as a PAT, a PMT, and a TOT (Time Offset Table). The PMT includes PID information F1 indicating the PID of a TS packet that stores audio information, video signals, etc., and a version number expressed using a value from 0 to 31. The version number is changed every time the data included in the PMT is updated, in accordance with the standard defined by ARIB.

[0024] The remux device 221 receives scrambled audio and video information from a distribution device (not shown) at a program distribution provider, and generates a plurality of TS packets containing information obtained by dividing the received audio and video information into a plurality of pieces. The remux device 221 also receives EPG information for a channel assigned to the remux device 221 from a management device (not shown), and generates a plurality of TS packets containing SI information for the channel based on the received EPG information. The remux device 221 transmits a broadcast signal, which is a stream containing the generated TS packets, to the transmitting device 231.

[0025] The transmitting device 231 transmits the broadcast signal received from the remux device 221 to the STB 351. For example, the transmitting device 231 generates a plurality of IP packets including the broadcast signal and transmits the generated IP packets to the STB 351 via the hub 311 and the CATV network 321. The transmitting device 231 may also be configured to transmit an RF signal including content to the STB 351. More specifically, the transmitting device 231 generates an RF signal by modulating the broadcast signal according to a predetermined modulation method such as QAM (Quadrature Amplitude Modulation), and transmits the generated RF signal to the STB 351 via the hub 311 and the CATV network 321.

[0026] The encoding device 111 acquires a plurality of contents corresponding to a plurality of independent broadcast channels from a storage unit inside or outside the encoding device 111. The encoding device 111 generates an audio ES (Elementary Stream) and a video ES by compressing the audio information and video information contained in the acquired contents, and transmits the generated audio ES and video ES to the remux device 121.

[0027] The remux device 121 receives audio ES and video ES from the encoding device 111 and generates a plurality of TS packets Pts including the received audio ES and a plurality of TS packets Pts including the received video ES. The remux device 121 also receives EPG information and various data for a channel assigned to the remux device 121 from a management device (not shown), and generates a plurality of TS packets Pts including SI information for the channel based on the received EPG information and various data. The remux device 121 transmits a non-scrambled signal, which is a stream including the generated TS packets Pts and NULL packets Pnull, to the scramble device 101.

[0028] The scrambling device 101 generates a scrambled signal by encrypting the non-scrambled signal received from the remuxing device 121 , and transmits the generated scrambled signal to the transmitting device 131 .

[0029] The transmitting device 131 transmits the scrambled signal received from the scrambling device 101 to the STB 351. More specifically, for example, the transmitting device 131 generates a plurality of IP packets including the scrambled signal, and transmits the generated IP packets to the STB 351 via the hub 311 and the CATV network 321. The transmitting device 131 may also be configured to transmit an RF signal including content to the STB 351. More specifically, the transmitting device 131 generates an RF signal by modulating the scrambled signal according to a predetermined modulation method such as QAM, and transmits the generated RF signal to the STB 351 via the hub 311 and the CATV network 321.

[0030] The control device 141 transmits descriptor information F2 relating to the scrambling key Ks to the scrambling device 101. More specifically, the control device 141 determines an ECMPID, which is the PID (Packet ID) of a TS packet in which an ECM containing the scrambling key Ks is stored, and transmits descriptor information F2 containing the determined ECMPID to the scrambling device 101. For example, the control device 141 periodically or irregularly determines a new ECMPID and transmits descriptor information F2 containing the determined ECMPID to the scrambling device 101.

[0031] (Scramble device) FIG. 2 is a diagram illustrating a configuration of a scrambling device according to an embodiment of the present disclosure. Referring to FIG. 2, the scrambling device 101 includes a receiving unit 11, a key generating unit 12, an ECM generating unit 13, a scrambling unit 14, a PMT blocking unit 15, a PMT acquiring unit 16, a PMT generating unit 17, a multiplexing unit 18, a transmitting unit 19, and a storage unit 20. The PMT generating unit 17 includes a generating unit 17A and a management unit 17B. Some or all of the receiving unit 11, the key generating unit 12, the ECM generating unit 13, the scrambling unit 14, the PMT blocking unit 15, the PMT acquiring unit 16, the PMT generating unit 17, the multiplexing unit 18, and the transmitting unit 19 are implemented by, for example, a processing circuit including one or more processors. The storage unit 20 is, for example, a nonvolatile memory included in the processing circuit.

[0032] The receiving unit 11 receives a non-scrambled signal including content from the remux device 121. The receiving unit 11 outputs the received non-scrambled signal to the scrambling unit 14, the PMT obtaining unit 16, and the transmitting unit 19.

[0033] (Scrambling) The key generation unit 12 generates a scramble key Ks. For example, the key generation unit 12 generates a new scramble key Ks at a generation timing according to a predetermined update period Ck. After generating the scramble key Ks, the key generation unit 12 outputs the generated scramble key Ks to the ECM generation unit 13 and the scrambler 14.

[0034] The ECM generation unit 13 generates an ECM packet Pecm, which is a TS packet that stores an ECM including a scrambling key Ks, at an ECM transmission timing that conforms to a predetermined transmission cycle Ce. More specifically, the ECM generation unit 13 receives descriptor information F2 from the control device 141. The ECM generation unit 13 generates an ECM including the latest scrambling key Ks received from the key generation unit 12 at the ECM transmission timing. After generating the ECM, the ECM generation unit 13 stores the generated ECM in the payload section and generates an ECM packet Pecm in which the ECM ID included in the latest descriptor information F2 received from the control device 141 is stored in the header section, and outputs the generated ECM packet Pecm to the multiplexer 18.

[0035] The scrambler 14 performs scrambling processing to generate a scrambled signal by encrypting a non-scrambled signal using the scramble key Ks. More specifically, the scrambler 14 encrypts the non-scrambled signal received from the receiver 11 using the latest scramble key Ks received from the key generator 12, thereby generating a scrambled signal including encrypted TS packets Pts. The scrambler 14 outputs the generated scrambled signal to the PMT blocking unit 15.

[0036] The PMT blocking unit 15 removes PMT packets Ppmt1, which are TS packets Pts that store a PMT, from the TS packets Pts included in the scrambled signal received from the scramble unit 14. More specifically, the PMT blocking unit 15 references the PID stored in the header of the TS packets Pts included in the scrambled signal received from the scramble unit 14, and extracts TS packets Pts with a PID of "0x0000" from the TS packets Pts included in the scrambled signal. Here, the PID of a TS packet Pts that includes a PAT is "0x0000." A number beginning with "0x" means that the numbers following "0x" are expressed in hexadecimal. The PMT blocking unit 15 obtains the PAT from the extracted TS packets Pts, and analyzes the obtained PAT to obtain the PID of the PMT packet Ppmt1.

[0037] Upon acquiring the PID of the PMT packet Ppmt1, the PMT blocking unit 15 starts removing the PMT packet Ppmt1 based on the acquired PID. Specifically, the PMT blocking unit 15 references the PID stored in the header of the TS packet Pts included in the scrambled signal received from the scramble unit 14, and determines that the TS packet Pts in which the acquired PID is stored, among the TS packets Pts included in the scrambled signal, is the PMT packet Ppmt1.

[0038] Then, the PMT blocking unit 15 removes the determined PMT packet Ppmt1 from the scrambled signal, and outputs the scrambled signal from which the PMT packet Ppmt1 has been removed to the multiplexing unit 18. More specifically, the PMT blocking unit 15 outputs the scrambled signal from which the PMT packet Ppmt1 has been replaced with a NULL packet Pnull to the multiplexing unit 18.

[0039] (Get PMT packet Ppmt1) The PMT acquisition unit 16 acquires a PMT packet Ppmt1 from the non-scrambled signal received by the receiving unit 11. For example, the PMT acquisition unit 16 repeatedly acquires the PMT packet Ppmt1. That is, the PMT acquisition unit 16 acquires the PMT packet Ppmt1 from the non-scrambled signal each time the PMT packet Ppmt1 is output from the receiving unit 11. The PMT packet Ppmt1 is an example of a first packet. More specifically, the PMT acquisition unit 16 references the PID stored in the header of the TS packet Pts included in the non-scrambled signal received from the receiving unit 11 and extracts TS packets Pts having a PID of "0x0000" from among the TS packets Pts included in the non-scrambled signal. The PMT acquisition unit 16 acquires a PAT from the extracted TS packet and analyzes the acquired PAT to acquire the PID of the PMT packet Ppmt1.

[0040] When the PMT acquisition unit 16 acquires the PID of the PMT packet Ppmt1, it starts extracting the PMT packet Ppmt1 based on the acquired PID. Specifically, the PMT acquisition unit 16 references the PID stored in the header of the TS packet Pts included in the non-scrambled signal received from the receiving unit 11, and determines that the TS packet Pts containing the acquired PID is the PMT packet Ppmt1, among the TS packets Pts included in the non-scrambled signal. The PMT acquisition unit 16 then extracts the determined PMT packet Ppmt1 from the non-scrambled signal and stores the extracted PMT packet Ppmt1 in the storage unit 20.

[0041] (Generation of PMT packet Ppmt2) The PMT generating unit 17 generates a PMT packet Ppmt2, which is a TS packet Pts including a PMT in which descriptor information F2 related to the scrambling key Ks is stored. The PMT generating unit 17 outputs the generated PMT packet Ppmt2 to the multiplexing unit 18.

[0042] More specifically, the generation unit 17A in the PMT generation unit 17 receives the descriptor information F2 from the control device 141 and stores the received descriptor information F2 in the storage unit 20. The generation unit 17A generates a PMT packet Ppmt2 including a PMT in which the latest descriptor information F2 in the storage unit 20 is stored. The PMT packet Ppmt2 is an example of a second packet.

[0043] For example, the generation unit 17A repeatedly generates a PMT packet Ppmt2 by adding descriptor information F2 to the PMT included in a PMT packet Ppmt1 acquired by the PMT acquisition unit 16. More specifically, each time the PMT acquisition unit 16 stores a PMT packet Ppmt1 in the storage unit 20, the generation unit 17A acquires the PMT packet Ppmt1 and the latest descriptor information F2 from the storage unit 20. The generation unit 17A generates a PMT packet Ppmt2 by adding the descriptor information F2 to the PMT packet Ppmt1.

[0044] The management unit 17B manages the version number of the PMT that stores the descriptor information F2 and that is generated within the scrambling device 101. More specifically, the management unit 17B manages the version number of the PMT included in the PMT packet Ppmt2 generated by the generation unit 17A.

[0045] (Comparison process) The management section 17B in the PMT generation section 17 increments the version number of the PMT included in the PMT packet Ppmt2 every time at least one of the PMT and the descriptor information F2 included in the PMT packet Ppmt1 is updated.

[0046] For example, the management unit 17B performs a comparison process to compare the PID information F1A and descriptor information F2A in the PMT contained in the PMT packet Ppmt2 generated by the generation unit 17A with the PID information F1B and descriptor information F2B in the PMT contained in the PMT packet Ppmt2 output to the multiplexing unit 18 immediately before.

[0047] If the comparison process finds that the PID information F1A and the PID information F1B do not match, or the descriptor information F2A and the descriptor information F2B do not match, the management unit 17B performs an increment process to increment the PMT version number included in the PMT packet Ppmt2 generated by the generation unit 17A.

[0048] Specifically, for example, if the version number of the PMT included in the PMT packet Ppmt2 is "zero," the management unit 17B changes the version number of the PMT to "1" in an increment process. Furthermore, for example, if the version number of the PMT included in the PMT packet Ppmt2 is "31," the management unit 17B changes the version number of the PMT to "zero" in an increment process. The management unit 17B then outputs the PMT packet Ppmt2 after the increment process to the multiplexer 18.

[0049] On the other hand, if the comparison process finds that the PID information F1A and the PID information F1B match and that the descriptor information F2A and the descriptor information F2B match, the management unit 17B does not increment the PMT version number included in the PMT packet Ppmt2 generated by the generation unit 17A. In this case, the management unit 17B outputs the PMT packet Ppmt2 generated by the generation unit 17A to the multiplexer 18.

[0050] (Adjustment processing) The PMT generation unit 17 performs an adjustment process to adjust the PMT version number included in the PMT packet Ppmt2 based on the PMT version number included in the PMT packet Ppmt1 acquired by the PMT acquisition unit 16. For example, in the adjustment process, the PMT generation unit 17 adjusts the PMT version number included in the PMT packet Ppmt2 so that the interval between the PMT version number included in the PMT packet Ppmt1 and the PMT version number included in the PMT packet Ppmt2 is 2 or more.

[0051] More specifically, the management unit 17B compares the PMT version number contained in the latest PMT packet Ppmt1 in the storage unit 20 with the PMT version number contained in the PMT packet Ppmt2 after the comparison process.

[0052] The management unit 17B calculates the interval NA between the PMT version number included in the PMT packet Ppmt1 and the PMT version number included in the compared PMT packet Ppmt2. If the difference D1 obtained by subtracting the PMT version number included in the PMT packet Ppmt1 from the PMT version number included in the compared PMT packet Ppmt2 is equal to or greater than zero, the interval NA is the difference D1. On the other hand, if the difference D1 is less than zero, the interval NA is the value obtained by adding 32 to the difference D1.

[0053] If the calculated interval NA is less than 2, the management unit 17B corrects the version number of the PMT included in the PMT packet Ppmt2 so that the interval NA is equal to or greater than 2. Specifically, if the calculated interval NA is less than 2, the management unit 17B corrects the version number of the PMT included in the PMT packet Ppmt2 to a smaller value or a larger value so that the interval NA is equal to or greater than 2. Then, the management unit 17B outputs the corrected PMT packet Ppmt2 to the multiplexer 18.

[0054] On the other hand, if the calculated interval NA is 2 or more, the management unit 17B outputs the PMT packet Ppmt2 to the multiplexer 18 without correcting the version number of the PMT included in the PMT packet Ppmt2.

[0055] (TS packet multiplexing) The multiplexing unit 18 multiplexes the PMT packet Ppmt2 generated by the PMT generation unit 17 onto the scrambled signal generated by the scrambler 14. More specifically, the multiplexing unit 18 replaces the NULL packet Pnull included in the scrambled signal received from the PMT blocking unit 15 with the PMT packet Ppmt2 received from the PMT generation unit 17 and the ECM packet Pecm received from the ECM generation unit 13, thereby multiplexing the PMT packet Ppmt2 and the ECM packet Pecm onto the scrambled signal. The multiplexing unit 18 outputs the scrambled signal into which the PMT packet Ppmt2 and the ECM packet Pecm are multiplexed to the transmitter 19.

[0056] The transmitting unit 19 transmits the scrambled signal into which the PMT packet Ppmt2 and the ECM packet Pecm have been multiplexed by the multiplexing unit 18. More specifically, the transmitting unit 19 transmits the scrambled signal received from the multiplexing unit 18 to the transmitting device 131.

[0057] The transmitter 19 can switch the signal to be transmitted from a scrambled signal to a non-scrambled signal. More specifically, the transmitter 19 can transmit the non-scrambled signal received from the receiver 11 instead of the scrambled signal received from the multiplexer 18.

[0058] For example, the transmitting unit 19 can switch the transmission signal between a scrambled signal and a non-scrambled signal in accordance with the operation of the administrator of the scrambling device 101.

[0059] Furthermore, for example, the transmitter 19 includes a normally closed relay, and switches the transmission signal from a scrambled signal to a non-scrambled signal in a hardware manner, i.e., forcibly, when the power supply to the scramble device 101 is cut off. In this case, the time required for the transmitter 19 to switch the transmission signal is sufficiently shorter than the cycle of incrementing the version number by the management unit 17B and the delay time Td described later.

[0060] 3 is a diagram illustrating an example of signals transmitted and received by a scrambling device according to an embodiment of the present disclosure, showing a non-scrambled signal received by the scrambling device 101 from the remuxing device 121 and a scrambled signal transmitted by the scrambling device 101 to the transmitting device 131.

[0061] 3, as described above, the PMT blocking unit 15 replaces the PMT packet Ppmt1 included in the scrambled signal with a NULL packet Pnull. For example, if a buffer or the like for delaying the scrambled signal is not provided between the scrambler 14 and the multiplexer 18, the multiplexer 18 receives the PMT packet Ppmt2 from the PMT generator 17 at a timing after receiving the NULL packet Pnull replaced by the PMT blocking unit 15. Therefore, the multiplexer 18 replaces the NULL packet Pnull received from the PMT blocking unit 15 after the NULL packet Pnull with the PMT packet Ppmt2, resulting in a delay time Td in the timing of sending the PMT from the scramble device 101.

[0062] (PMT version number transition) 4 is a diagram showing an example of transition of the version number of the PMT included in the signal transmitted and received by the scrambling device according to the embodiment of the present disclosure. Fig. 4 shows the transition of the version number of the PMT included in the non-scrambled signal received by the scrambling device 101 from the remuxing device 121, the transition of the version number of the PMT included in the scrambled signal generated by the scrambling device 101, and the transition of the version number of the PMT included in the transmission signal transmitted by the scrambling device 101 to the transmitting device 131.

[0063] Referring to FIG. 4, the version number of the PMT included in the non-scrambled signal transmitted from the remux device 121 to the scramble device 101 is, for example, "0x04" in the initial state.

[0064] Furthermore, the version number of the PMT included in the PMT packet Ppmt2 output by the PMT generation unit 17 to the multiplexing unit 18 is adjusted to "0x06" in the initial state so that the interval NA is, for example, "2." Furthermore, in the initial state, the transmitting unit 19 transmits to the transmitting device 131 a scrambled signal including a PMT whose version number is "0x06."

[0065] Thereafter, the version number of the PMT included in the non-scrambled signal transmitted by the remux device 121 to the scramble device 101 is changed from "0x04" to "0x05" at time t1, for example, in conjunction with the update of the PID information F1.

[0066] In this case, the version number of the PMT included in the PMT packet Ppmt2 output by the PMT generation unit 17 to the multiplexing unit 18 is changed from "0x06" to "0x07" at time t2, which is a delay time Td after time t1. Furthermore, after time t2, the transmitting unit 19 transmits a scrambled signal including a PMT with the version number "0x07" to the transmitting device 131.

[0067] Furthermore, when the power supply to the scrambling device 101 is cut off at time ts after time t2, the transmitting unit 19 in the scrambling device 101 switches the transmission signal from a scrambled signal to a non-scrambled signal. In this case, the version number of the PMT sent by the scrambling device 101 switches from "0x07" to "0x05," which is different before and after time ts, and therefore does not violate the standards defined by ARIB.

[0068] Fig. 5 is a diagram showing an example of the transition of the version number of the PMT included in the signal transmitted and received by the scrambling device according to the comparative example. Fig. 5 shows the transition of the version number of the PMT included in the non-scrambled signal received by the scrambling device according to the comparative example from the remux device 121, the transition of the version number of the PMT included in the scrambled signal generated by the scrambling device according to the comparative example, and the transition of the version number of the PMT included in the transmission signal transmitted by the scrambling device according to the comparative example to the transmission device 131.

[0069] Referring to Figure 5, for example, a scrambling device in the comparative example generates, in its initial state, a PMT packet Ppmt2 whose PMT version number is "0x04", the same as that of the PMT packet Ppmt1, and transmits a scrambled signal including the generated PMT packet Ppmt2 to the transmitting device 131.

[0070] Thereafter, the version number of the PMT included in the non-scrambled signal transmitted by the remux device 121 to the scramble device according to the comparative example is changed from "0x04" to "0x05" at time t1, for example, in conjunction with the update of the PID information F1.

[0071] In this case, the scrambling device according to the comparative example generates a PMT packet Ppmt2 having a PMT version number of "0x05" after time t2, and transmits to the transmitting device 131 a scrambled signal including the generated PMT packet Ppmt2.

[0072] Furthermore, when the power supply to the scrambling device according to the comparative example is cut off at time ts, the transmission signal is switched from a scrambled signal to a non-scrambled signal. In this case, the PMT sent by the scrambling device according to the comparative example is switched at time ts from a PMT that does not include descriptor information F2 to a PMT that includes descriptor information F2, but the version number of the PMT is the same before and after time ts, which violates the standards defined by ARIB.

[0073] 6 is a diagram showing an example of transition of the version number of the PMT included in the signal transmitted and received by the scrambling device according to the embodiment of the present disclosure. Compared to FIG. 4, FIG. 6 shows transition of the version number of the PMT included in the transmission signal when the scrambling device 101 switches the transmission signal to be transmitted to the transmitting device 131 at time ts between time t1 and time t2.

[0074] 6, when the power supply to the scrambling device 101 is cut off at time ts between time t1 and time t2, the transmitting unit 19 in the scrambling device 101 switches the transmission signal from a scrambled signal to a non-scrambled signal. In this case, the version number of the PMT sent by the scrambling device 101 switches from "0x06" to "0x05," which is different before and after time ts, and therefore does not violate the standards defined by ARIB.

[0075] [Operation flow] FIG. 7 is a flowchart defining an example of an operation procedure when a scrambling device according to an embodiment of the present disclosure transmits a scrambled signal.

[0076] Referring to FIG. 7, first, scrambling device 101 receives a non-scrambled signal (step S11).

[0077] Next, the scrambling device 101 generates a scramble signal using the scrambling key Ks (step S12).

[0078] Next, the scrambling device 101 obtains the PMT packet Ppmt1 from the non-scrambled signal (step S13).

[0079] Next, the scramble device 101 generates a PMT packet Ppmt2 by adding descriptor information F2 to the PMT contained in the PMT packet Ppmt1 (step S14).

[0080] Next, the scrambling device 101 multiplexes the PMT packet Ppmt2 onto the scrambled signal from which the PMT packet Ppmt1 has been removed (step S15).

[0081] Next, the scrambling device 101 transmits the scrambled signal in which the PMT packet Ppmt2 is multiplexed to the transmitting device 131 (step S16).

[0082] 8 is a flowchart showing an example of an operation procedure when the scrambling device according to the embodiment of the present disclosure acquires the PMT packet Ppmt1, and shows details of step S13 in FIG.

[0083] Referring to Figure 8, first, the PMT acquisition unit 16 in the scrambling device 101 refers to the PID of the TS packets Pts included in the non-scrambled signal received from the receiving unit 11, and extracts TS packets Pts whose PID is "0x0000" from the TS packets Pts included in the non-scrambled signal (step S21).

[0084] Next, the PMT obtaining unit 16 obtains the PAT from the extracted TS packet, and analyzes the obtained PAT to obtain the PID of the PMT packet Ppmt1 (step S22).

[0085] Next, the PMT acquisition unit 16 starts extracting the PMT packet Ppmt1 based on the acquired PID (step S23).

[0086] Next, the PMT acquisition unit 16 waits for the arrival of the PMT packet Ppmt1 (NO in step S24), and if it detects the PMT packet Ppmt1 included in the non-scrambled signal (YES in step S24), it extracts the PMT packet Ppmt1 from the non-scrambled signal (step S25).

[0087] Next, the PMT acquisition unit 16 stores the extracted PMT packet Ppmt1 in the storage unit 20 (step S26).

[0088] Next, the PMT acquisition unit 16 waits for the arrival of a new PMT packet Ppmt1 (NO in step S24).

[0089] 9 is a flowchart showing an example of an operation procedure when the scrambling device according to the embodiment of the present disclosure generates the PMT packet Ppmt2, and shows details of step S14 in FIG.

[0090] Referring to Figure 9, first, the generation unit 17A in the PMT generation unit 17 of the scrambling device 101 waits for the PMT packet Ppmt1 to be stored in the memory unit 20 (NO in step S31), and when the PMT acquisition unit 16 stores the PMT packet Ppmt1 in the memory unit 20 (YES in step S31), it acquires the PMT packet Ppmt1 and the latest descriptor information F2 from the memory unit 20 (step S32).

[0091] Next, the generating unit 17A generates a PMT packet Ppmt2 by adding the obtained descriptor information F2 to the obtained PMT packet Ppmt1 (step S33).

[0092] Next, the management unit 17B in the PMT generation unit 17 of the scrambling device 101 performs a comparison process to compare the PID information F1A and descriptor information F2A in the PMT contained in the PMT packet Ppmt2 generated by the generation unit 17A with the PID information F1B and descriptor information F2B in the PMT contained in the PMT packet Ppmt2 output to the multiplexing unit 18 immediately before (step S34).

[0093] Next, if there is a PMT update, i.e., if the PID information F1A and the PID information F1B do not match, or if the descriptor information F2A and the descriptor information F2B do not match (YES in step S35), the management unit 17B performs an increment process to increment the PMT version number included in the PMT packet Ppmt2 generated by the generation unit 17A (step S36).

[0094] On the other hand, if the PMT has not been updated, that is, if the PID information F1A and the PID information F1B match and the descriptor information F2A and the descriptor information F2B match (NO in step 35), the management unit 17B does not perform the increment process.

[0095] Next, the management unit 17B calculates the interval NA between the PMT version number included in the latest PMT packet Ppmt1 in the storage unit 20 and the PMT version number included in the PMT packet Ppmt2 after the comparison process (step S37).

[0096] Next, if the interval NA is less than 2 (YES in step S38), the management unit 17B corrects the version number of the PMT included in the PMT packet Ppmt2 so that the interval NA is 2 or more (step S39).

[0097] On the other hand, if the interval NA is 2 or more (NO in step S38), the management unit 17B does not correct the version number.

[0098] Next, the management unit 17B outputs the PMT packet Ppmt2 to the multiplexing unit 18 (step S40).

[0099] Next, the generation unit 17A waits for a new PMT packet Ppmt1 to be stored in the storage unit 20 (NO in step S31).

[0100] In the scrambling device 101 according to the embodiment of the present disclosure, the generator 17A in the PMT generator 17 is configured to generate the PMT packet Ppmt2 by adding descriptor information F2 to the PMT included in the PMT packet Ppmt1, but this is not limited to this. Instead of using the PMT included in the PMT packet Ppmt1, the generator 17A may be configured to obtain PID information F1 from the control device 141, and generate the PMT packet Ppmt2 based on the obtained PID information F1 and descriptor information F2.

[0101] Furthermore, in the scrambling device 101 according to the embodiment of the present disclosure, the management unit 17B in the PMT generation unit 17 is configured to increment the version number of the PMT included in the PMT packet Ppmt2 each time at least one of the PMT and the descriptor information F2 included in the PMT packet Ppmt1 is updated, but this is not limited to this. Instead of incrementing the version number of the PMT included in the PMT packet Ppmt2 each time at least one of the PMT and the descriptor information F2 included in the PMT packet Ppmt1 is updated, the management unit 17B may be configured to determine the version number of the PMT included in the PMT packet Ppmt2 regardless of the version number of the PMT packet Ppmt2 output in the past.

[0102] (Variation) In the scrambling device 101 according to the embodiment of the present disclosure, the PMT generation unit 17 is configured to adjust the version number of the PMT included in the PMT packet Ppmt2 so that the interval NA is 2 or more, but this is not limited to this. The PMT generation unit 17 may also be configured to adjust the version number of the PMT included in the PMT packet Ppmt2 so that the interval NA is 1.

[0103] 10 is a diagram showing an example of transitions in the version number of a PMT included in a signal transmitted and received by a scrambling device according to a modified example of an embodiment of the present disclosure. Fig. 10 shows transitions in the version number of a PMT included in a non-scrambled signal received by a scrambling device according to a modified example from a remuxing device 121, transitions in the version number of a PMT included in a scrambled signal generated by a scrambling device according to a modified example, and transitions in the version number of a PMT included in a transmission signal transmitted to a transmitting device 131 by a scrambling device according to a modified example.

[0104] Referring to FIG. 10, the scrambling device according to the modification adjusts the version number of the PMT included in the PMT packet Ppmt2 to "0x05" so that the interval NA becomes "1" in the initial state.

[0105] Thereafter, the version number of the PMT included in the non-scrambled signal transmitted by the remux device 121 to the scramble device according to the modified example is changed from "0x04" to "0x05" at time t1, for example, in conjunction with the update of the PID information F1.

[0106] In this case, the scrambling device according to the modified example generates a PMT packet Ppmt2 whose PMT version number is "0x06" after time t2, and transmits to the transmitting device 131 a scrambled signal including the generated PMT packet Ppmt2.

[0107] Furthermore, when the power supply to the scrambling device according to the modified example is cut off at time ts, the transmission signal is switched from a scrambled signal to a non-scrambled signal. In this case, the version number of the PMT sent by the scrambling device according to the modified example is switched from "0x06" to "0x05," which is different before and after time ts, and therefore does not violate the standards defined by ARIB.

[0108] Fig. 11 is a diagram showing an example of transition of the version number of the PMT included in a signal transmitted and received by a scrambling device according to a modified embodiment of the present disclosure. Compared to Fig. 10, Fig. 11 shows transition of the version number of the PMT included in the transmission signal when the scrambling device switches the transmission signal to be transmitted to the transmitting device 131 at time ts between time t1 and time t2.

[0109] 11, the scrambling device according to the modified example switches the transmission signal from a scrambled signal to a non-scrambled signal when the power supply to the scrambling device 101 is cut off at time ts between time t1 and time t2. In this case, the PMT sent by the scrambling device according to the modified example switches at time ts from a PMT that does not include descriptor information F2 to a PMT that includes descriptor information F2, while the version number of the PMT remains the same before and after time ts, which violates the standard defined by ARIB.

[0110] In contrast, in the scrambling device 101 according to an embodiment of the present disclosure, even if the power supply to the scrambling device 101 is cut off at time ts between time t1 and time t2, the PMT can be transmitted in accordance with the standard set by ARIB.

[0111] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0112] Each process (each function) in the above-described embodiments is realized by a processing circuit including one or more processors. The processing circuit may be configured as an integrated circuit or the like that combines one or more memories, various analog circuits, and various digital circuits in addition to the one or more processors. The one or more memories store programs (instructions) that cause the one or more processors to execute each of the processes. The one or more processors may execute each of the processes according to the program read from the one or more memories, or according to a logic circuit pre-designed to execute each of the processes. The processor may be various processors suitable for computer control, such as a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a field programmable gate array (FPGA), and an application-specific integrated circuit (ASIC). Note that the physically separate processors may cooperate with each other to execute each of the processes. For example, the processors mounted on a plurality of physically separated computers may cooperate with each other to execute the above processes via a network such as a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, etc. The program may be installed into the memory from an external server device or the like via the network, or may be distributed in a state stored on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a semiconductor memory, and installed into the memory from the recording medium.

[0113] The above description includes the following additional features. [Appendix 1] A scrambling device, a receiving unit for receiving a non-scrambled signal including content; a PMT acquisition unit that acquires a first packet including a PMT from the non-scrambled signal received by the receiving unit; a scrambling unit that generates a scrambled signal by encrypting the non-scrambled signal using a scrambling key; a PMT generator that generates a second packet including a PMT that stores descriptor information related to the scrambling key; a multiplexing unit that multiplexes the second packet generated by the PMT generating unit onto the scrambled signal generated by the scrambling unit; a transmitting unit that transmits the scrambled signal into which the second packet is multiplexed by the multiplexing unit, the PMT generation unit adjusts the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet acquired by the PMT acquisition unit; The scrambling device, wherein the transmitting unit switches the transmission signal from the scrambled signal to the non-scrambled signal by hardware when the power supply to the scrambling device is cut off.

[0114] [Appendix 2] A scrambling device, a processing circuit; The processing circuitry receiving a non-scrambled signal containing content; obtaining a first packet including a PMT from the received non-scrambled signal; generating a scrambled signal by encrypting the non-scrambled signal using a scrambling key; generating a second packet including a PMT in which descriptor information relating to the scrambling key is stored; multiplexing the generated second packet onto the generated scrambled signal; transmitting the scrambled signal into which the second packet is multiplexed; a scrambling device that adjusts the version number of the PMT included in the second packet based on the version number of the PMT included in the acquired first packet; [Explanation of symbols]

[0115] 11 Receiving unit 12 Key generation section 13 ECM generation section 14 Scramble Section 15 PMT blocking part 16 PMT Acquisition Department 17 PMT generation section 17A Generation part 17B Management Department 18 Multiplex section 19 Transmitter 20 Memory section 101 Scramble Device 111 Encoding Device 121 Remax Device 131 Transmitting device 141 Control device 221 Remax Device 231 Transmitting Device 301 Station Building 311 Hub 321 CATV network 351 STB 401 Broadcasting System Pts TS packet Ppmt1, Ppmt2 PMT packets Pnull NULL packet t1,t2,ts time

Claims

1. a receiving unit for receiving a non-scrambled signal including content; a PMT acquisition unit that acquires a first packet including a PMT (Program Map Table) from the non-scrambled signal received by the receiving unit; a scrambling unit that generates a scrambled signal by encrypting the non-scrambled signal using a scrambling key; a PMT generating unit that generates a second packet including a PMT in which descriptor information related to the scrambling key is stored; a multiplexing unit that multiplexes the second packet generated by the PMT generating unit onto the scrambled signal generated by the scrambling unit; a transmitter that transmits the scrambled signal into which the second packet is multiplexed by the multiplexer, The PMT generation unit adjusts the version number of the PMT included in the second packet based on the version number of the PMT included in the first packet acquired by the PMT acquisition unit.

2. the transmitter is capable of switching the signal to be transmitted from the scrambled signal to the non-scrambled signal; The scrambling device according to claim 1, wherein the PMT generation unit adjusts the version number of the PMT included in the second packet so that the interval between the version number of the PMT included in the first packet and the version number of the PMT included in the second packet is 2 or more.

3. 3. The scrambling device according to claim 1, wherein the PMT generating unit generates the second packet by adding the descriptor information to a PMT included in the first packet acquired by the PMT acquiring unit.

4. the PMT acquisition unit repeatedly acquires the first packet; the PMT generation unit repeatedly generates the second packet; 4. The scrambling device according to claim 3, wherein the PMT generation unit increments a version number of the PMT included in the second packet every time at least one of the PMT included in the first packet and the descriptor information is updated.

5. A scrambling method in a scrambling device, comprising: receiving a non-scrambled signal containing content; obtaining a first packet including a PMT from the received non-scrambled signal; generating a scrambled signal by encrypting the non-scrambled signal with a scrambling key; generating a second packet including a PMT in which descriptor information relating to the scrambling key is stored; multiplexing the generated second packet onto the generated scrambled signal; transmitting the scrambled signal into which the second packet is multiplexed; A scrambling method, wherein in the step of generating the second packet, the version number of the PMT included in the second packet is adjusted based on the version number of the PMT included in the obtained first packet.

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