JP6183881B2 - Codec conversion gateway, codec conversion method, and codec conversion program - Google Patents

Description

  The present invention relates to a codec conversion gateway, a codec conversion method, and a codec conversion program that enable communication between devices using different encoding methods.

  A codec is a device, function, or algorithm that performs encoding on a code of a specific encoding method or decoding from a code of a specific encoding method with respect to data such as audio, moving images, and images.

  The codec conversion is to convert a code encoded by one codec into a code of an encoding method used by another codec when there are a plurality of types of codecs.

  When a plurality of terminals do not support a common encoding method, each terminal cannot reproduce data such as voice, moving image, and image received from the counterpart terminal. In such a case, for example, the data received from the partner terminal can be reproduced by relaying the data after the codec conversion gateway mutually converts the encoding methods of the partner terminal and the terminal itself.

  An example of codec conversion is disclosed in Patent Document 1. The codec conversion system disclosed in Patent Document 1 includes two IP (Internet Protocol) telephone terminals, a codec conversion gateway (session border controller), a codec conversion device, and a SIP (Session Initiation Protocol) connected to different operator networks. And a server. The gateway includes a plurality of interface units, a control unit, and a switch unit. The codec conversion system of Patent Document 1 operates as follows.

  The SIP server uses a codec applied to each IP telephone terminal that is going to make a call during the SIP session establishment process (encoding method adopted by the carrier network in which each IP telephone terminal is accommodated). Recognize If the encoding methods of the two IP telephone terminals are different, the SIP server issues a codec conversion start instruction to the codec conversion gateway. A session is a logical communication path from a transmission source to a transmission destination.

  In the codec conversion gateway, the control unit to which the codec conversion start instruction is given controls the interface unit, the switch unit, and the codec conversion device, and prepares codec conversion.

  Specifically, the control unit prepares the packet from one IP telephone terminal to be transferred to the codec converter by the interface unit and the switch unit that accommodate the IP telephone terminal. Alternatively, the control unit prepares the codec conversion device to convert the code of the encoding method of the packet into the encoding method applied to the other IP telephone terminal. Then, the control unit prepares the packet output from the codec conversion device so that the switch unit and the interface unit that accommodates the other IP telephone terminal transmit the packet to the other IP telephone terminal. Further, the control unit similarly prepares to execute codec conversion in the reverse direction.

  When codec conversion is enabled, the control unit returns a message “Codec conversion start OK” to the SIP server, and the SIP server notifies both IP phone terminals of “call OK”. Notify the message.

  The packet related to the call started in this way is converted into a packet of a code of the encoding method applied by the opposite IP telephone terminal via the codec conversion device, and is transmitted to the opposite IP telephone terminal.

  As in the above operation, in the codec conversion system of Patent Document 1, when the encoding method of the opposite IP phone terminal is different, the SIP server allows the call path between the IP phone terminals to pass through the codec conversion device. Instructs the codec conversion gateway.

  Note that the codec conversion system disclosed in Patent Document 1 requires a SIP server that is a dedicated session control device in addition to the terminal and the codec conversion gateway.

  In communication between terminals in a telephone, an IP phone, a videophone, a conference system, instant messaging, and the like, session control such as start, change, and end of a session is necessary.

  For session control between terminals, a session control dedicated device may be required separately from the terminal. For example, as a session control protocol in a public switched telephone network, No. 7 common line signaling may be used. No. In the 7 common line signaling, an exchange may be required for session control. As a session control protocol in an IP network, H.264 is used. 323, SIP, etc. may be used. For session control, H.264. A gatekeeper (telephone number management server) may be required for H.323, and a SIP server (SIP proxy server) may be required for SIP. As a session control protocol in an IP network connected via a public switched telephone network, H.264 is used. 248 (Megaco), MGCP (Media Gateway Control Protocol), etc. may be used. H. In 248 and MGCP, a media gateway controller (call agent), media gateway and signaling gateway may be required for session control.

  An example of a telephone system that does not use a session control dedicated device is disclosed in Patent Document 2. The IP telephone system of Patent Document 2 includes one IP network and a plurality of IP telephone terminals connected to the IP network. The IP telephone terminal includes a terminal list information storage unit. The IP telephone terminal of Patent Document 2 operates as follows.

  All IP telephone terminals already connected to the IP network hold correspondence information between identification information and IP addresses of all IP telephone terminals already connected in the terminal list information storage unit.

  When the new IP telephone terminal is connected to the IP network, the correspondence information between the identification information of the new IP telephone terminal and the IP address is transmitted to one already connected IP telephone terminal.

  One IP phone terminal that has received the correspondence information between the new IP phone terminal identification information and the IP address adds the correspondence information between the new IP phone terminal identification information and the IP address to the terminal list information storage unit. Then, the contents of the terminal list information storage unit are transmitted to the new IP telephone terminal and other IP telephone terminals already connected to the IP network.

  As a result of the above operation, in this IP telephone system, each IP telephone terminal can talk to each other without using a dedicated session control device.

  An example of a call center system that does not require a specific device such as a SIP server is disclosed in Patent Document 3. The call center system disclosed in Patent Document 3 includes a plurality of main lines for external lines, a plurality of sub lines used for other purposes, and a call request to a telephone connected to an external line from an operator's IP telephone to a customer's IP telephone. First and second communication control servers that perform connection processing, and a management server that manages the lines and the status of the first and second communication control servers. A gateway is provided between the operator's IP telephone and the IP network to which the customer's IP telephone is connected, and performs protocol conversion between IP / SIP. Each of the communication control server, the operator's IP phone, and the management server performs data communication using the IP protocol or a dedicated message. The call center system of Patent Document 3 operates as follows.

  First, when there is no free main line in the server, the first communication control server that has received the call request queries the management server for a communication control server that has a free main line.

  Next, the first communication control server receives free line information indicating that the main line of the second communication control server is free from the management server, and uses the sub line of the first communication control server. Connect to the second communication control server, connect to the customer's IP phone via the external line (including the external line IP network and gateway) using the main line of the second communication control server, and establish a call.

  As a result of the above operation, this call center system does not require a specific device such as a SIP server.

JP 2009-267628 A (page 5-6, FIG. 4) JP 2010-239336 A (page 6-13, FIG. 1-7) JP 2011-223474 A (page 3-9, FIGS. 1-4)

  In the technique disclosed in Patent Document 1, an instruction from a SIP server, which is a dedicated session control device, is required to start codec conversion. Therefore, there is a problem that the technique disclosed in Patent Document 1 cannot be applied to a system that does not manage a session. Even in a system including a session control dedicated device, if the function for instructing the start of codec conversion is not provided, it is necessary to add that function to the session control dedicated device.

  In the technique disclosed in Patent Document 2, each IP telephone terminal can talk to each other without using a SIP server which is a session control dedicated device. However, since this telephone system does not support the codec conversion function in the first place, it is necessary to add the codec conversion function in order to realize the codec conversion.

  Similarly, the technique disclosed in Patent Literature 3 can also construct a call center system without using a SIP server that is a session control dedicated device. However, since this call center system does not support the codec conversion function, it is necessary to add the codec conversion function in order to realize the codec conversion.

  An object of the present invention is to provide a codec conversion gateway, a codec conversion method, and a codec conversion program capable of starting codec conversion by a codec conversion gateway alone without requiring an external instruction such as an instruction from a session control dedicated device. There is to do.

  The codec conversion gateway according to the present invention includes a conversion rule storage unit that stores a conversion rule of an encoding scheme set in association with a set of a packet transmission source and a packet first transmission destination, and a conversion rule based on the conversion rule. Conversion means for converting the encoding method of the received packet.

  The codec conversion method of the present invention converts the encoding method of a received packet based on an encoding method conversion rule set in association with a set of a packet transmission source and a packet first transmission destination. It is characterized by doing.

  The codec conversion program according to the present invention includes a codec conversion gateway including a conversion rule storage unit that stores a conversion rule of an encoding scheme that is set in association with a set of a packet transmission source and a packet first transmission destination. A computer provided is operated as a conversion means for converting the encoding method of a received packet based on a conversion rule.

  According to the present invention, there is an effect that codec conversion can be started by a codec conversion gateway alone without requiring an external instruction.

It is a block diagram which shows the structure of the codec conversion gateway in the 1st Embodiment of this invention. It is a block diagram which shows an example of the hardware constitutions of the codec conversion gateway in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the codec conversion gateway in the 1st Embodiment of this invention. It is a figure which shows an example of the conversion rule in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the codec conversion gateway in the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the codec conversion gateway in the 2nd Embodiment of this invention. It is a figure which shows an example of the session list | wrist in the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the codec conversion gateway in the 3rd Embodiment of this invention. It is a figure which shows an example of the conversion rule in the 3rd Embodiment of this invention. It is a figure which shows an example of the session list | wrist in the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.
(First embodiment)
FIG. 1 is a block diagram showing a configuration of a codec conversion gateway in the first embodiment of the present invention.

  The codec conversion gateway 100 of this embodiment includes a conversion rule storage unit 105 and codec conversion means 107.

  The codec conversion gateway 100 is connected to the transmission terminal 200 and the reception terminal 300. The codec conversion gateway 100 may be connected to the transmission terminal 200 or the reception terminal 300 via a session control dedicated device (not shown) such as a SIP server. Note that, here, the configuration of only one direction is shown by paying attention to the data flow from the transmission terminal 200 to the reception terminal 300. However, when both terminals perform bidirectional communication, they are also symmetrical in the opposite direction. You may have a structure.

  Conversion rules are stored in the conversion rule storage unit 105 in advance. Each conversion rule includes information on a transmission source and a transmission destination of a packet for determining a packet that is a codec conversion target, and information on encoding methods before and after the codec conversion included in the packet that is a codec conversion target.

  Note that the information on the transmission source and transmission destination of the packet for determining the packet to be codec converted includes one of the following items for each of the transmission source and the transmission destination.

1) Terminal identifier or range 2) Application identifier or range on the terminal 3) User identifier or range of the terminal 4) Others included in the packet subject to codec conversion, and the source or destination Arbitrary information to be specified or its range 5) Combination of items in paragraphs 1 to 4 6) Arbitrary items to be included in packets that are subject to codec conversion and items that are subject to codec conversion and to limit packets that are subject to codec conversion The identification information in any one of items 1-5, which can identify each of the transmission source and the transmission destination, is essential. Since the transmission source and the transmission destination may be a terminal or an application, each specific information is information that can identify the terminal and the application, for example. That is, the specific information includes a terminal identifier or its range (address), or an application identifier or its range (port number). And the encoding system before conversion and after conversion are specified with respect to the set of two specific information which designates the transmission origin and transmission destination with which the packet which needs conversion is transmitted / received. In addition, when the information of the encoding system before conversion is contained in the packet which is a codec conversion object, the information of the encoding system before conversion in a conversion rule may be abbreviate | omitted.

  For a set that does not require conversion, there may or may not be information on the encoding scheme and information on the set itself. In addition, when the range of information specifying or limiting the transmission source or transmission destination of a packet that needs to be converted is the entire range that the information can take, the information in the range may or may not be present.

  As an additional information for a set of two specific information that designates a transmission source and a transmission destination for transmitting and receiving a packet that needs to be converted, for example, a packet of a packet that the transmission source notifies the transmission stop of the packet to the transmission destination. Transmission destination information, timeout time information for determining timeout, and the like may be added.

  The codec conversion unit 107 refers to the conversion rule stored in the conversion rule storage unit 105 to check whether or not the received packet corresponds to a conversion target packet for which the conversion rule is set. If the packet corresponds to the conversion target packet, the codec conversion unit 107 transmits the packet to the receiving terminal 300 after converting the encoding method of the received packet. If the packet does not correspond to the conversion target packet, the codec conversion unit 107 transmits the packet to the receiving terminal 300 as it is.

  Here, the packet is, for example, IP, X. 25, or a packet of a network layer protocol such as CLNP (Connection Less Network Protocol). The payload of the network layer protocol packet may be a transport layer protocol packet such as UDP (User Datagram Protocol). Further, the payload of the packet of the network layer protocol or the transport layer protocol is, for example, a session layer protocol such as RTP (Real-time Transport Protocol) (here, in particular, a data stream such as voice or video is delivered in real time). Protocol) packet.

  FIG. 2 is a block diagram illustrating an example of a hardware configuration of the codec conversion gateway.

  The codec conversion gateway 907 includes a storage device 902, a CPU (Central Processing Unit) 903, a keyboard 904, a monitor 905, and an I / O (Input / Output) 908, which are connected via an internal bus 906. Yes. The storage device 902 stores an operation program for the CPU 903 such as the codec conversion unit 107. The CPU 903 controls the entire codec conversion gateway 907, executes an operation program stored in the storage device 902, executes programs such as the codec conversion means 107 and transmits / receives data via the I / O 908. The internal configuration of the codec conversion gateway 907 is an example. The codec conversion gateway 907 may include only the CPU 903 and operate using a storage device 902, a keyboard 904, a monitor 905, and an I / O 908 provided outside.

  Next, the operation of this embodiment will be described.

  FIG. 3 is a flowchart showing the operation of the codec conversion gateway in the present embodiment. However, the operation for one received packet is shown. The operation for receiving a plurality of packets is repeated for one packet.

  The codec conversion means 107 receives a packet from the transmission terminal 200 (step S110).

  The codec conversion unit 107 refers to the conversion rule stored in the conversion rule storage unit 105 to check whether or not the received packet corresponds to a conversion target packet for which the conversion rule is set (step S130).

  If the received packet corresponds to the packet to be converted for which the conversion rule is set (step S130: Yes), the codec conversion means 107 determines the encoding method of the received packet before codec conversion indicated in the conversion rule. The coding method is converted to the coding method after the codec conversion indicated in the conversion rule (step S150).

  If the received packet does not correspond to the packet to be converted for which the conversion rule is set (step S130: No), the encoding method of the received packet is not converted, and the process proceeds to the next step S160.

  The codec conversion means 107 transmits a packet to the receiving terminal 300 (step S160).

  FIG. 4 is a diagram illustrating an example of a conversion rule in the first embodiment of the present invention. The first column in FIG. 4 indicates the range of the source IP address of the IP packet that is the target of codec conversion, the second column indicates the range of the destination port number of the UDP packet included in the IP packet that is the target of codec conversion, The third column shows the codec type before conversion, and the fourth column shows the codec type after conversion. For example, the source IP address in the IP packet is included in the IP address “aa.aa.aa.aa” having the net mask length “ee”, and the destination UDP port number is “A” or more and “E” or less. The IP packet corresponds to the conversion target of the conversion rule in the second row, and the RTP packet included in the payload of the IP packet is encoded by “AMR” (Adaptive Multi-Rate), and “EVRC” ( This indicates that it should be converted to an encoding method based on Enhanced Variable Rate Codec).

  As described above, the codec conversion gateway according to the present embodiment does not require an external instruction, and can start codec conversion by the codec conversion gateway alone. The reason is that the codec conversion unit 107 determines the codec conversion target packet and executes codec conversion defined in advance in the conversion rule.

  In addition, since the codec conversion gateway in the present embodiment does not use a session control dedicated device such as a SIP server, there is an effect that the cost of the session control dedicated device such as a SIP server does not occur.

In addition, since the codec conversion gateway in the present embodiment does not use a session control protocol such as SIP, an effect that does not cause a compatibility problem of the session control protocol in connection with a device using a session control protocol such as a SIP server. There is also.
(Second Embodiment)
FIG. 5 is a block diagram showing the configuration of the codec conversion gateway in the second exemplary embodiment of the present invention.

  In the following description, descriptions common to the first embodiment and the present embodiment are omitted, and only differences of the present embodiment from the first embodiment will be described.

  The configuration of the codec conversion gateway in the second embodiment of the present invention is obtained by adding a session list 109 connected to the codec conversion means 107 to the configuration of the codec conversion gateway in the first embodiment.

  The information on the transmission source and transmission destination of the packet for determining the packet that is the codec conversion target included in the conversion rule specifies one or more sessions (one or more sets of transmission source and transmission destination). On the other hand, in the individual session information stored in the session list 109, the packet transmission source and transmission destination information for determining the packet that is the codec conversion target included in the session information is one session (transmission source and transmission source). 1 set of transmission destinations) is specified.

  In the collation of the correspondence between the packet and the conversion rule, it is necessary to compare the identifier included in the packet with the range of identifiers included in the conversion rule. On the other hand, the matching of the correspondence between the packet and the session information can be performed by comparing the identifier included in the packet with the identifier included in the session information.

  In addition, the codec conversion means may require conversion preparation (child process activation, etc.) and post-conversion processing (end of the child process, etc.) for each set of encoding methods before and after codec conversion. At that time, for example, when there are many combinations of encoding methods before and after codec conversion and it is difficult to always maintain preparation for conversion, if there is no session list, preparation for conversion, conversion processing, conversion Post processing must be performed. On the other hand, if there is a session list, the conversion ready state corresponding to the existing session can be maintained. Also, the conversion ready state corresponding to the terminated session can be released.

  Therefore, after conversion is prepared for a session, if the session information has an identifier (such as an identifier of a child process) for identifying the prepared conversion process, a packet corresponding to the session corresponds. Can be passed to the session conversion process. In the following, each session information in the session list holds an identifier of a set of encoding methods before and after the codec conversion generated based on the conversion rule applied to the session, and the conversion applied by the identifier Is identified.

  The session list 109 stores one piece of session information for one session to which the conversion rule is applied (a real-time data stream including RTP packets and the like). Each session information includes one set of packet source and destination information for uniquely identifying a session and codec conversion method information applied to the packet corresponding to the session (for example, before and after codec conversion). Information of each encoding method).

  The packet transmission source and transmission destination information for identifying the session includes any of the following items for each of the transmission source and the transmission destination.

1) Terminal identifier 2) Application identifier on the terminal 3) Terminal user identifier 4) Other arbitrary information included in the packet to be codec converted to identify the source or destination 5) First The combination of items in item -4 The identification information in any one of items 1-5 that can identify each of the transmission source and the transmission destination is essential.

  The codec conversion means 107 can add information for identifying a session to the session list 109 based on the received packet and the conversion rule applied to the packet.

  Next, the operation of this embodiment will be described.

  FIG. 6 is a flowchart showing the operation of the codec conversion gateway in the present embodiment.

  Steps S110, S130, and 150 to S160 are the same as steps S110, S130, and 150 to S160 of the first embodiment of the present invention.

  The codec conversion means 107 checks whether or not a session corresponding to the received packet is registered in the session list 109 (step S120). The session is identified by, for example, a transmission source IP address included in the received IP packet and a transmission destination port number included in the UDP packet.

  If the session corresponding to the received packet is not registered in the session list 109 (step S120: No), step S130 is executed.

  If the received packet corresponds to the packet to be converted in which the conversion rule is set (step S130: Yes), the codec conversion unit 107 uniquely identifies the session corresponding to the received packet (for example, received Information that identifies the source IP address included in the IP packet and the destination port number included in the UDP packet) and the set of encoding methods before and after codec conversion applied to the packet belonging to the session (for example, conversion The encoding method information before and after conversion copied from the conversion rule of the storage unit 105 is registered in the session list 109 (step S140).

  If a session corresponding to the received packet is registered in the session list 109 (step S120: Yes), the codec conversion unit 107 executes step S150. However, in the present embodiment, the codec conversion unit 107 performs codec conversion according to information for identifying a set of encoding methods before and after conversion registered in the session list 109, copied from the conversion rule included in the conversion rule unit 105. Execute.

  FIG. 7 is a diagram showing an example of a session list in the second embodiment of the present invention. The first column in FIG. 7 shows the source IP address of the received IP packet, and the second column shows the destination port number of the UDP packet included in the received IP packet. For example, the second line indicates that the source IP address is “aa.aa.aa.aa” and the destination RTP port number is “A”. In columns 3 to 4 of FIG. 7, pre-conversion codec information (“AMR”) and post-conversion codec information (“EVRC”) copied from the conversion rule of the conversion storage unit 105 are registered.

  As described above, the codec conversion gateway according to the present embodiment does not require an external instruction, and can start codec conversion by the codec conversion gateway alone. The reason is that the codec conversion means 107 determines the codec conversion target packet using the session list 109 and executes the codec conversion defined in advance in the conversion rule.

Furthermore, the codec conversion gateway in the present embodiment can reduce the number of times of referring to conversion rules. The reason is that the codec conversion means 107 refers to the conversion rule storage unit only when the received packet is not registered in the session list 109.
(Third embodiment)
The configuration of the codec conversion gateway in the third embodiment of the present invention is the same as the configuration of the codec conversion gateway in the second embodiment of the present invention shown in FIG.

  However, the conversion rule held by the conversion rule storage unit 105 in this embodiment is not limited to the information held by the conversion rule storage unit 105 in the second embodiment, but is information on the notification destination of the session end (for example, a real-time data stream). (Identification information of the packet for notifying the end of transmission).

  In addition, the conversion information held in the session list 109 according to the present embodiment includes information on the notification destination of the session end (for example, transmission end of the real-time data stream) in addition to the conversion information held in the session list 109 according to the second embodiment The packet identification information) and the last reception time of the packet corresponding to the session. Here, the information of the session end notification destination is copied from the conversion rule held by the conversion rule storage unit 105 by the codec conversion means 107. In addition, the last reception time of the packet corresponding to the session is updated by the codec conversion means 107.

  Further, the codec conversion means 107 holds a predetermined session timeout time.

  In the following description, descriptions common to the second embodiment and the present embodiment are omitted, and only differences of the present embodiment from the second embodiment will be described.

  Next, the operation of this embodiment will be described.

  FIG. 8 is a flowchart showing the operation of the codec conversion gateway in the present embodiment.

  Steps S110 to S160 are the same as steps S110 to S160 of the second embodiment of the present invention.

  However, in step S140 of the third embodiment of the present invention, a session end notification destination as an item to be copied from the conversion rule held by the conversion rule storage unit 105 to the session list 109 in the second embodiment of the present invention. (For example, identification information of a packet that notifies the end of transmission of a real-time data stream) is added.

  The codec conversion means 107 transmits a packet to the receiving terminal 300 (step S160). Next, the codec conversion means 107 checks the transmitted packet in accordance with the session end notification destination information held in the session list 109. At this time, if the payload of the transmitted packet includes a packet for notifying the end of the session (transmission end of the real-time data stream) (step S170: Yes), the codec conversion unit 107 adds the corresponding session from the session list 109. Delete (step S180).

  Here, the packet for notifying the end of transmission of the data stream may be an IP packet including a “BYE” packet of RTCP (Real-time Transport Control Protocol), for example.

  The codec conversion means 107 updates the last packet reception time for each session held in the session list 109 for the packet transmitted to the receiving terminal 300 in step S160, and all the values held in the session list 109 according to a preset timeout value. The session that has timed out is deleted from the session list 109 (step S190).

  In this example, the codec conversion unit 107 has a session deletion function, but another unit may be provided.

  In addition, the session deletion function by a packet that notifies the end of transmission of the real-time data stream may be omitted.

  FIG. 9 is a diagram illustrating an example of a conversion rule in the third embodiment of the present invention. The first to fourth columns in FIG. 9 are the same as the first to fourth columns in FIG. 4 in the first embodiment of the present invention. The fifth column in FIG. 9 shows the destination port number of the UDP packet when the IP packet notifying the end of transmission of the real-time data stream includes an RTCP packet. For example, in the second line, the source IP address in the IP packet is included in the IP address “aa.aa.aa.aa” having the netmask length “ee”, and the destination UDP port number is “A” or more and “E”. "If it is less than or equal to, the IP packet corresponds to the conversion target of the conversion rule in the second row, and the destination port number of UDP (payload is RTCP) notifying the end of transmission of the data stream belonging to the session is" H " This indicates that it is “L” or less.

  FIG. 10 is a diagram showing an example of a session list in the third embodiment of the present invention. The first to fourth columns in FIG. 10 are the same as the first to fourth columns in FIG. 7 in the second embodiment of the present invention. The fifth column in FIG. 10 shows the destination port number of the UDP packet when the IP packet notifying the end of transmission of the real-time data stream includes the RTCP packet, and the sixth column is when the payload of the received IP packet includes the RTP packet The last reception time of the IP packet by the codec conversion gateway is shown. For example, in the second line, there is a session whose source IP address is “aa.aa.aa.aa” and whose UDP (payload is RTP) destination port number “A”, and data belonging to that session The destination port number of UDP (payload is RTCP) for notifying the end of transmission of the stream is “H to L”, and the last reception time of the RTP packet belonging to the session by the codec conversion gateway is “hh: MM: SS”. It shows that there is.

  In step S170, the codec conversion means 107 monitors the UDP destination port number in the fifth column in FIG. 10 and notifies the end of transmission (for example, an RTCP “BYE” packet. Information of the RTP session to be ended) Is included in the “BYE” packet).

  The codec conversion means 107 can delete the time-out session from the session list by subtracting the “last packet reception time” in the session list from the current time and comparing it with a predetermined session time-out time.

  As described above, the codec conversion gateway according to the present embodiment does not require an external instruction, and can start codec conversion by the codec conversion gateway alone. The reason is that the codec conversion means 107 determines the start of the session of the real-time data stream using the session list 109 and executes codec conversion defined in advance in the conversion rule.

  Furthermore, the codec conversion gateway according to the present embodiment does not require an instruction from the outside, and the codec conversion can be completed by the codec conversion gateway alone. The reason is that the codec conversion means 107 uses the session list 109 to determine the end of the session of the real-time data stream and deletes the corresponding session from the session list.

  In addition, this invention is not limited to the above-mentioned embodiment, It can implement in various changes and deformation | transformation in the range which does not deviate from the summary of this invention.

Claims (10)

One or more transmission sources of the packet, one or more first transmission destinations of the packet, an encoding method in the packet transmitted from the transmission source, and the transmission to the first transmission destination A conversion rule storage unit that stores in advance a conversion rule that can specify the encoding method in the packet ;
Conversion means for converting the encoding method of the received packet based on the conversion rule;
A codec conversion gateway comprising: The conversion rule is:
First identification information for identifying the transmission source;
Second identification information for identifying the first transmission destination;
First encoding scheme identification information for identifying an encoding scheme applied at the transmission source;
Second encoding scheme identification information for identifying an encoding scheme applied at the first destination;
The codec conversion gateway according to claim 1, comprising: The first identification information is information that identifies a terminal or application program that is the transmission source, or a user of the terminal,
The codec conversion gateway according to claim 2, wherein the second identification information is information identifying a terminal or an application program that is the first transmission destination or a user of the terminal. A series of packets that are transmitted from a source of the one or more sources to a first destination of the one or more first destinations based on the conversion rule; And a session list that holds a correspondence with a conversion method from a first encoding method applied at the certain transmission source to a second encoding method applied at the certain first transmission destination. The codec conversion gateway according to any one of claims 1 to 3. The session list further holds the last reception time of the series of packets.
5. The conversion unit according to claim 4, further comprising: determining a time-out for receiving the series of packet groups according to a time-out value set in advance, and deleting the time-out association from the session list. Codec conversion gateway. When the conversion means receives the transmission end notification of the series of packet groups transmitted from the transmission source to the first transmission destination or the second transmission destination of the transmission end notification of the series of packet groups. 6. The codec conversion gateway according to claim 4, wherein the association is deleted from the session list. 7. The codec conversion gateway according to claim 6, wherein the notification of the end of transmission of the series of packet groups is an IP packet including an RTCP BYE packet in a payload. The codec conversion gateway according to claim 1, wherein the packet is an IP packet including an RTP packet in a payload. One or more transmission sources of the packet, one or more first transmission destinations of the packet, an encoding method in the packet transmitted from the transmission source, and the transmission to the first transmission destination based on the previously stored conversion rule capable of specifying a coding scheme in a packet, the codec conversion method and converting the encoding method of the received packet. One or more transmission sources of the packet, one or more first transmission destinations of the packet, an encoding method in the packet transmitted from the transmission source, and the transmission to the first transmission destination A computer provided in a codec conversion gateway including a conversion rule storage unit that stores in advance a conversion rule capable of specifying an encoding method in a packet ;
A codec conversion program for operating as conversion means for converting the encoding method of a received packet based on the conversion rule.

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