JP3846853B2 - Information distribution system and information distribution method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information distribution system for distributing predetermined information from a transmitting station to a receiving station through a predetermined network, and a technology related thereto.
[0002]
[Prior art]
When distributing video and audio on a predetermined network, http (hyper transfer protocol), which is frequently used on the Internet, supports session-type standardized communication with a TCP connection. In this case, TCP (transmission control protocol) / IP (internet protocol) having processing functions such as error detection, retransmission, and flow control is often employed in the transport layer.
[0003]
On the other hand, in a dedicated network for one-way transmission of information such as networks, such as when video captured by an imaging camera and audio collected by a microphone are distributed in real time to a remote location Even if a slight network failure occurs, the failure is allowed, and when such a network failure occurs, the latest video and audio are delivered even if the past video and audio are discarded. There may be a request to do. In such cases, UDP (user datagram protocol) is a transport layer communication protocol that does not guarantee network reliability (support for network failures, etc.), and does not require confirmation between networks. However, efficient communication rather than TCP / IP can be realized.
[0004]
[Problems to be solved by the invention]
In general, when a large amount of data such as video and audio is distributed, packet loss occurs when the network condition is not good such as a large number of collisions or when the client does not have reception capability. In particular, in the case of video and audio data, since the amount of data for one piece is large, the number of packets constituting one piece of video and audio is increased. Here, in the case of TCP / IP, various processes such as retransmission for packet transmission are performed, but when video and audio data is distributed using the UDP protocol, support for network failure and the like is not performed. Due to packet loss, it is often impossible to construct one image or the like, and depending on the situation, it may be difficult to reproduce video and audio.
[0005]
Accordingly, an object of the present invention is to provide an information distribution system and related technology capable of reducing degradation of video and audio while efficiently distributing large amounts of data such as video and audio in a one-way manner. Is to provide.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is an information distribution system for distributing predetermined information from a transmitting station to a receiving station through a predetermined network, wherein the transmitting station, the receiving station, and the relay A server, and the receiving station includes information receiving means for receiving information from the transmitting station, and a reception loss management unit for detecting a degree of loss occurring in the information received by the information receiving means, When the information reception means initially requests the transmission station to transmit information in UDP, and the loss of information detected by the reception loss management unit exceeds a predetermined threshold, the transmission station together provide a distribution stop request to provide the video and audio information distribution request in TCP / IP to the relay server, the relay server, TCP from the information receiving means of the receiving station / When the information distribution request in P is given, given the information distribution request in UDP to the transmitting station, the information in the UDP given from the transmitting station to the TCP / IP accordingly The data is converted and transmitted to the receiving station.
[0008]
The invention according to claim 2 is the information distribution system according to claim 1 , wherein the receiving station receives the information in units of packets, and the number of packet losses exceeds a predetermined threshold. The loss of information exceeds a predetermined threshold.
[0010]
The invention according to claim 3 is an information distribution method for distributing predetermined information from a transmitting station to a receiving station through a predetermined network, wherein the receiving station distributes information to the transmitting station by UDP. A second step in which the transmitting station transmits information to the receiving station by UDP after the first step, and information in UDP that the receiving station gives from the transmitting station A third step of determining the degree of loss of the first and a second step in which the receiving station makes a distribution stop request to the transmitting station when the degree of information loss exceeds a predetermined threshold in the third step. After the fourth step, the fifth step after the fourth step, the receiving station makes a TCP / IP information distribution request to a predetermined relay server, and after the fifth step, The relay server sends the UDP information to the transmitting station. A sixth step of making a communication request, a seventh step in which the transmitting station transmits information to the relay server by UDP after the sixth step, and after the seventh step, the relay An eighth step in which the server converts the information in UDP given from the transmitting station into TCP / IP; and after the eighth step, the relay server sends information to the receiving station in TCP / IP. And a ninth step of transmitting.
[0011]
The invention according to claim 4 is the information distribution method according to claim 3 , wherein in the third step, the receiving station receives the information in units of packets and the number of lost packets. In the fourth step, the receiving station determines that the degree of information loss has exceeded a predetermined threshold when the number of packet losses has exceeded a predetermined threshold.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
{First embodiment}
FIG. 1 is a diagram showing an information distribution system according to the first embodiment of the present invention. In general, when a video and audio data packet is distributed from the transmitting station 1 to the receiving station 2 by UDP, a sequential number is added to the packet, and when the packet loss occurs, the lost packet is recognized. It is a mechanism that can. By utilizing this fact, this information distribution system requests that the receiving station 2 switch from UDP to TCP when the receiving station 2 recognizes that packet loss frequently occurs. Based on this request, the transmitting station 1 delivers video and audio to the receiving station 2 by TCP / IP.
[0013]
Specifically, this information distribution system has a configuration in which a transmitting station 1 and a receiving station 2 are connected to a predetermined network 3 such as a LAN.
[0014]
The transmission station 1 has a ROM, a RAM, and a CPU, and is an electronic unit that operates according to a software program stored in the ROM or the like in advance. As shown in FIG. 2, a video / audio compression unit 11 that compresses video and audio. The distribution request processing unit 12 that determines the content of the distribution request when a distribution request is received from the receiving station 2, and the video / audio compression unit 11 compresses the content according to the content determined by the distribution request processing unit 12. A video / audio distribution unit 16 that determines whether the compressed data is distributed by UDP 13 or TCP / IP 14 and distributes the compressed data to the receiving station 2 through the network 3 through the LAN driver 15. The video / audio distribution unit 16 has a function of assigning sequential numbers to video and audio data when data is distributed using the UDP 13.
[0015]
As shown in FIG. 3, the receiving station 2 includes a video / audio receiving unit (information receiving unit) 21 that receives video and audio data in units of packets through the LAN driver 20 using the UDP 20a or TCP / IP 20b, and a video / audio receiving unit. Video / audio data received at 21 is displayed on a display monitor (not shown) by performing predetermined video and audio processing, and video / audio data is recorded on a recording device (not shown). The audio reproduction unit 22 and a reception loss management unit 23 that detects the degree of loss occurring in the packet received by the video / audio reception unit 21 are provided.
[0016]
The reception loss management unit 23 detects packet loss by determining whether or not sequential numbers included in video and audio data are continuously received.
[0017]
The video / audio receiving unit 21 then transports the video and audio data transmission protocol to the transmitting station 1 when the packet loss detected by the reception loss management unit 23 exceeds a predetermined threshold. Is provided with a protocol change request function for requesting to change from UDP to TCP. Specifically, for example, in the case of video data, if one frame of video cannot be configured due to packet loss, if the sequence continues N (eg, 3) times or more, the distribution protocol is changed from UDP 20a to TCP / IP 20b, and again Make a delivery request. Or when half of the number of frames delivered per second cannot be played back, or when 30 frames / second of video and audio is delivered, but the actual playback was less than 15 frames. The distribution protocol is changed from UDP 20a to TCP / IP 20b, and a distribution request is made again.
[0018]
In FIG. 1, reference numeral 4 denotes a hub, and reference numeral 5 denotes a relay server.
[0019]
4 shows a processing flow on the transmitting station 1 side, and FIG. 5 shows a processing flow on the receiving station 2 side.
[0020]
In the information distribution system configured as described above, the transmitting station 1 first waits for a distribution request from the receiving station 2 in step S01 in FIG.
[0021]
On the receiving station 2 side, initially, in step T01 in FIG. 5, a distribution request in the UDP 20a is given to the transmitting station 1 side through the network 3.
[0022]
Returning to the processing flow on the transmitting station 1 side (FIG. 4), in step S02 (see FIG. 6), the distribution request given from the receiving station 2 side is received, and in step S03, the distribution request processing unit 12 performs TCP / IP14. It is determined whether or not a distribution request has been made. Then, it is determined that there is a distribution request in UDP 13, and the process proceeds to step S04. In step S04 (see FIG. 6), a sequential number is added to the video and audio data in accordance with a normal UDP 13 distribution method, and this is transmitted to the receiving station 2 side via the network 3 via the UDP 13.
[0023]
On the receiving station 2 side, the video and audio data given from the transmitting station 1 is received in step T02. In step T03, it is determined whether or not sequential numbers included in the video and audio data are continuously received. If the sequential numbers are consecutive, the process proceeds to step T04, and the received video and audio are reproduced by the video / audio reproduction unit 22.
[0024]
As described above, the processing of steps S01 to S04 is repeatedly performed on the transmitting station 1 side, and the processing of steps T01 to T04 is repeatedly performed on the receiving station 2 side.
[0025]
By the way, when the reception loss management unit 23 determines in step T03 on the receiving station 2 side that the sequential numbers are not consecutive, the process proceeds to step T05, and the number of missing packets is accumulated. In step T06, the video / audio receiving unit 21 determines whether the number of missing packets (number of packet loss) detected by the reception loss management unit 23 exceeds a predetermined threshold value.
[0026]
If it is determined in step T06 that the number of missing packets does not exceed the predetermined threshold, the processes in steps T02 to T06 are repeated.
[0027]
On the other hand, if it is determined in step T06 that the number of missing packets exceeds a predetermined threshold, the process proceeds to step T07.
[0028]
In step T07, the current distribution is stopped (see FIG. 6), and a distribution request in TCP / IP 20b is given to the transmitting station 1 through the network 3 (see FIG. 6).
[0029]
Returning to the processing flow on the transmitting station 1 side (FIG. 4), in the repetitive processing of steps S01 to S04, it is determined in step T03 that there has been a delivery request from the receiving station 2 via TCP / IP 14, and the process proceeds to step T05. . In step T05, the video and audio data are transmitted to the receiving station 2 by TCP / IP 14 (see FIG. 6).
[0030]
On the receiving station 2 side, the process proceeds to step T08 in FIG. 5, and the video and audio data given by the TCP / IP 20b from the transmitting station 1 is received and reproduced by the video / audio reproduction unit 22.
[0031]
As described above, initially, video and audio data distribution is performed with UDP suitable for one-way information distribution, while transmission is performed when the packet loss exceeds a certain threshold on the receiving station 2 side. Since the distribution protocol from the station 1 to the receiving station 2 is changed from UDP to TCP / IP, the packet loss increases, for example, while the one-way information distribution is efficiently performed by UDP at normal times. When there is a problem such that a single picture cannot be constructed, the deterioration of video and audio can be easily reduced by TCP / IP.
[0032]
{Second Embodiment}
<Configuration>
FIG. 7 is a block diagram showing a processing flow of the information distribution system according to the second embodiment of the present invention. In FIG. 7, elements having the same functions as those of the first embodiment are denoted by the same reference numerals. As shown in FIG. 7, in the information distribution system of this embodiment, when the transmitting station 1 side has only the function of the UDP distribution protocol, the number of packet losses at the receiving station 2 exceeds a predetermined threshold. In addition, video and audio data provided from the transmitting station 1 is converted into a TCP / IP system by the relay server 5 and provided to the receiving station 2.
[0033]
Specifically, the relay server 5 makes a UDP / IP data distribution request to the transmitting station 1 when a TCP / IP distribution request is given from the receiving station 2. It has a function of converting UDP video and audio data given from the transmitting station 1 in response to TCP / IP and giving it to the receiving station 2.
[0034]
The video / audio receiving unit (information receiving unit) 21 of the receiving station 2 gives a transmission stop request to the transmitting station 1 when the packet loss exceeds a predetermined threshold in the reception loss management unit 23. In addition, the relay server 5 has a function of giving a video / audio data distribution request by TCP / IP.
[0035]
As a processing procedure, in step U01, a video and audio data distribution request in UDP is directly transmitted from the receiving station 2 to the transmitting station 1 through the network 3. In response to this, in step U02, the transmitting station 1 distributes video and audio data in UDP to the receiving station 2.
[0036]
Here, if the receiving station 2 determines that the packet loss has exceeded a predetermined threshold value as in the first embodiment, the distribution is stopped from the receiving station 2 to the transmitting station 1 in step U03. Make a request. Subsequently, in step U04, the receiving station 2 sends a TCP / IP distribution request to the relay server 5. At this time, the relay server 5 makes a UDP distribution request to the transmitting station 1 in step U05. In response to this, the transmitting station 1 distributes video and audio data to the relay server 5 by UDP (step U06). The relay server 5 converts the UDP video and audio data given from the transmitting station 1 into TCP / IP and transmits it to the receiving station 2 (step U07).
[0037]
According to this method, even if the communication situation between the transmitting station 1 and the receiving station 2 deteriorates and packet loss increases, the communication situation between the transmitting station 1 and the relay server 5 deteriorates. If not, a large amount of data can be given to the receiving station 2 without delay by retransmitting video and audio data in units of packets by TCP / IP via the relay server 5. Therefore, the same advantages as those of the first embodiment can be obtained.
[0038]
In the above embodiment, the distribution of video and audio data has been described as an example. Needless to say, the present invention can be applied to information distribution of any content as long as a large amount of data is transmitted in real time. .
[0040]
【The invention's effect】
According to the invention according to any one of claims 1 to 4 , when the transmitting station does not have a TCP / IP distribution function, the information is initially set by UDP suitable for one-way information distribution. On the other hand, when the loss of information (packet) exceeds a certain threshold on the receiving station side, the relay server changes the distribution protocol from the transmitting station to the receiving station and transmits it from UDP to TCP / IP. Therefore, in the normal case, while one-way information distribution is efficiently performed by UDP, degradation of video and audio can be easily reduced by TCP / IP when information loss increases.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing an overall configuration of an information distribution system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a transmitting station of the information distribution system according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a receiving station of the information distribution system according to the first embodiment of the present invention.
FIG. 4 is a flowchart showing a processing flow in a transmitting station of the information distribution system according to the first embodiment of the present invention.
FIG. 5 is a flowchart showing a processing flow in the receiving station of the information distribution system according to the first embodiment of the present invention.
FIG. 6 is a block diagram showing an overall processing flow of the information distribution system according to the first embodiment of the present invention.
FIG. 7 is a block diagram showing an overall processing flow of an information distribution system according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transmitting station 2 Receiving station 3 Network 5 Relay server 11 Video / audio compression unit 12 Distribution request processing unit 15 LAN driver 16 Video / audio distribution unit 20 LAN driver 21 Video / audio reception unit 22 Video / audio reproduction unit 23 Reception loss management Part

Claims (4)

An information distribution system for distributing predetermined information from a transmitting station to a receiving station through a predetermined network,
The transmission station, the reception station and a relay server,
The receiving station receives information from the transmitting station; and information receiving means;
A reception loss management unit that detects the degree of loss that has occurred in the information received by the information receiving means,
When the information reception means initially requests the transmission station to transmit information in UDP, and the loss of information detected by the reception loss management unit exceeds a predetermined threshold, the transmission A distribution stop request is given to the station, and a video / audio information distribution request in TCP / IP is given to the relay server,
When the relay server receives the information delivery request in TCP / IP from the information receiving means of the receiving station, the relay server gives the information delivery request in UDP to the transmitting station, and accordingly An information distribution system, wherein information in UDP given from the transmitting station is converted into TCP / IP and transmitted to the receiving station. The information distribution system according to claim 1,
The receiving station receives the information in units of packets, and the loss of information exceeds a predetermined threshold when the number of packet losses exceeds a predetermined threshold. Information distribution system. An information distribution method for distributing predetermined information from a transmitting station to a receiving station through a predetermined network,
  A first step in which the receiving station requests the transmitting station to distribute information by UDP;
  A second step in which the transmitting station transmits information to the receiving station by UDP after the first step;
  A third step in which the receiving station determines the degree of information loss in UDP given by the transmitting station;
  A fourth step in which, when the degree of information loss in the third step exceeds a predetermined threshold, the receiving station makes a distribution stop request to the transmitting station;
  A fifth step in which the receiving station makes a TCP / IP information distribution request to a predetermined relay server after the fourth step;
  After the fifth step, a sixth step in which the relay server makes a UDP information distribution request to the transmitting station;
  After the sixth step, a seventh step in which the transmitting station transmits information to the relay server by UDP;
  After the seventh step, an eighth step in which the relay server converts information in UDP given from the transmitting station into TCP / IP;
  After the eighth step, a ninth step in which the relay server transmits information to the receiving station by TCP / IP;
An information delivery method comprising: The information distribution method according to claim 3,
In the third step, the receiving station receives the information in units of packets and detects the number of lost packets,
In the fourth step, the receiving station determines that the degree of information loss exceeds a predetermined threshold value when the number of packet losses exceeds a predetermined threshold value. Method.

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