JP2017139521A - Stream distributing device, stream receiving device, stream distributing system, stream distributing method, and stream distributing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately estimate an available band of a network in stream distribution.SOLUTION: A stream distributing device comprises: stream packet transmitting means for transmitting stream data to a stream receiving device including stream packet receiving means for receiving the stream data and a packet stream for estimation and available band estimating means for estimating an available band of a network on the basis of the received packet stream for estimation to the stream receiving device; and transmission method determining means for determining a transmission method for transmitting a part of the stream data as the packet stream for estimation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stream distribution device, a stream reception device, a stream distribution system, a stream distribution method, and a stream distribution program for distributing stream data such as video and audio, and particularly in a best-effort network whose quality is not guaranteed. The present invention relates to a stream distribution device, a stream reception device, a stream distribution system, a stream distribution method, and a stream distribution program.

  In a best effort network such as the Internet or a mobile network, the usable bandwidth of the network varies greatly depending on the congestion state and wireless communication quality. Hereinafter, the “network available bandwidth” is simply referred to as “available bandwidth”. In such an environment, in order to improve the quality at the time of distributing stream data such as video, it is possible to control the bit rate (data amount per unit time) of the stream data according to the fluctuation of the available bandwidth. is necessary.

  Non-Patent Document 1 discloses a method for estimating a user experience quality index in a videophone which is one form of video distribution. According to Non-Patent Document 1, the user experience quality of a videophone varies depending on the bit rate, delay, and packet loss rate. The user experience quality is better as the bit rate is higher and the delay and packet loss rate are lower. In a packet communication network, devices in the network have a queue. Therefore, when the bit rate of the stream data to be transmitted exceeds the available bandwidth, the stream data is temporarily stored in the queue, and the delay of the stream data increases. This increase in delay is a factor that lowers the user experience quality. Also, since the queue length is finite, if the bit rate of stream data greatly exceeds the available bandwidth, the queue overflows and packet loss occurs. Packet loss is also a factor in reducing the user experience quality. Therefore, in order to maximize the user experience quality, it is desirable that the stream data is distributed at the same bit rate as the usable bandwidth.

  As a general method for measuring the available bandwidth, there is a method of calculating throughput by transmitting data of a predetermined data size at a time and dividing the data size by the time taken for reception. Hereinafter, this method is referred to as “throughput measurement method”. For example, when the data is a video stream, the above calculation can be performed for each video frame (one frame of video). In the throughput measurement method, if the “time required for reception” is sufficiently long, an accurate usable bandwidth can be measured. However, when the time taken for reception is short, the measurement error in the throughput measurement method is large, or the measurement error is so large that the throughput measurement method is not effective.

  In general, the communication apparatus notifies the upper layer of packet reception completion when packet reception is completed. Therefore, when the data size of the data to be transmitted is small and the data can be contained in one packet, the notification of data reception completion occurs only once. When the notification of data reception completion occurs only once, the upper layer cannot calculate the “time taken for reception” of the data. Therefore, the upper layer cannot calculate the data throughput. Even if the data spans multiple packets, if the “reception time” is short, the measurement error of the data throughput will be large due to the influence of fluctuations in the OS (Operating System) interrupt timing, etc. May be. In other words, the throughput measurement method has a problem that the available bandwidth cannot be measured or the measurement error of the available bandwidth is large when the data size of the data is small.

  Therefore, a packet sequence for measuring the available bandwidth including a plurality of packets having a relatively small packet size is transmitted, and the available bandwidth is estimated based on delay variation in reception of each packet included in the packet sequence. Technology is disclosed. Hereinafter, the packet sequence for measuring the available bandwidth is referred to as “packet train”. Each packet constituting the packet train for measuring the available bandwidth is referred to as a “measurement packet”. The data (payload) included in the measurement packet is referred to as “measurement data”. The packet train includes a series of measurement packets characterized by packet size and packet transmission interval, and there are several types of packet trains. Hereinafter, a packet train transmission method characterized by packet size and packet transmission interval is referred to as a “packet train transmission method”. Also, a method for measuring available bandwidth using a packet train is referred to as a “packet train measurement method”. In the packet train measurement method, the available bandwidth of the network can be measured with high accuracy using a relatively small amount of measurement data.

  In the packet train measurement method of Patent Document 1, the transmission side transmits each packet included in the packet train whose packet size linearly increases with time at a constant time interval. That is, in the packet train measurement method of Patent Document 1, the bit rate of the packet train increases with time. When the packet train bit rate exceeds the available bandwidth, the delay of the received packet increases. Therefore, the receiving side uses the bit rate at the packet size at which the delay starts to increase as the estimated value of the usable bandwidth. As a result of the above operation, in the packet train measurement method of Patent Document 1, the available bandwidth is estimated using measurement data having a relatively small data size.

  In the packet train measurement method of Non-Patent Document 2, the transmission side transmits a plurality of packet trains having a constant bit rate. The receiving side observes the delay time of the packets that make up each packet train. If the delay time tends to increase, the bit rate is larger than the available bandwidth, and if the delay time does not tend to increase, the bit rate Is less than the available bandwidth. The transmission side transmits the packet train while changing the bit rate, and the reception side uses the maximum bit rate at which the delay time does not tend to increase as the estimated available bandwidth. As a result of the above operation, in the packet train measurement method of Non-Patent Document 2, the available bandwidth is estimated using measurement data having a relatively small data size.

  In the packet train measurement method of Non-Patent Document 3, the transmission side transmits a packet of a certain size while gradually reducing the transmission interval. In the packet train measurement method of Patent Document 3, as with the packet train measurement method of Patent Document 1, the bit rate necessary for transmitting the packet train increases with time. The receiving side estimates the available bandwidth based on the transmission interval and size of the packet immediately before the reception interval becomes larger than the transmission interval. As a result of the above operation, in the packet train measurement method of Non-Patent Document 3, the available bandwidth is estimated using measurement data having a relatively small data size.

JP 2011-142622 A

ITU-T Recommendation G.1070, "Multimedia Quality of Service and performance-Generic and user-related aspects". M. Jain and C. Dovrolis, "Pathload: A Measurement Tool for End-to-end Available Bandwidth," In Proceedings of the 3rd Passive and Active Measurements Workshop, March 2002, Fort Collins CO. V. Ribeiro, R. Riedi, R. Baraniuk, J. Navratil, and L. Cottrell, "pathChirp: Efficient Available Bandwidth Estimation for Network Paths," In Proceedings of the 4th Passive and Active Measurements Workshop, April 2003, La Jolla, CA.

With the packet train measurement methods of Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3, it is possible to estimate the available bandwidth with relatively high accuracy using measurement data having a relatively small data size. . However, when the above-described packet train measurement method is used during transmission of stream data, there is a problem that an estimation error of an available band becomes large. For example, in stream data, generally, stream data is transmitted at a time for every 20 milliseconds in the case of audio and for each video frame in the case of video. Therefore, when the above-described packet train measurement method is used simultaneously with stream distribution, the delay of the packet train changes due to the influence of the stream data. As a result, the estimated value of the available bandwidth changes depending on the reception timing of the stream data and the packet train. Therefore, the packet train measurement methods of Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3 have a problem that the estimation accuracy of the available bandwidth is low in the stream distribution system.
(Object of invention)
A main object of the present invention is to provide a stream distribution device, a stream reception device, a stream distribution system, a stream distribution method, and a stream distribution program capable of accurately estimating the available bandwidth of a network in stream distribution. It is.

  The stream delivery apparatus of the present invention includes a stream packet receiving unit that receives stream data and an estimation packet sequence, and a stream reception unit that includes an available bandwidth estimation unit that estimates an available network bandwidth based on the received estimation packet sequence. A stream packet transmitting means for transmitting stream data to the apparatus, and a transmission method determining means for determining a transmission method for transmitting a part of the stream data as an estimation packet sequence are provided.

  The stream receiving apparatus of the present invention includes: a stream distribution apparatus including a stream packet transmitting unit that transmits stream data; and a transmission method determining unit that determines a transmission method for transmitting a part of the stream data as an estimation packet sequence. It is characterized by comprising stream packet receiving means for receiving stream data and an estimation packet sequence, and usable bandwidth estimation means for estimating an available network bandwidth based on the received estimation packet sequence.

  A stream distribution system according to the present invention includes a stream receiving device including an available bandwidth estimation unit that estimates an available bandwidth of a network based on a received estimation packet sequence, a stream packet transmission unit that transmits stream data, and stream data And a stream distribution device including a transmission method determining means for determining a transmission method for transmitting a part of the packet as an estimation packet sequence.

  The stream distribution method of the present invention determines a transmission method for transmitting a part of stream data as an estimation packet sequence, transmits the stream data, receives the stream data and the estimation packet sequence, and receives the estimation packet received The available bandwidth of the network is estimated based on the sequence.

  A stream distribution program according to the present invention includes a stream packet receiving unit that receives stream data and an estimation packet sequence, and a stream reception unit that includes an available bandwidth estimation unit that estimates an available network bandwidth based on the received estimation packet sequence. The apparatus is characterized by causing a computer to execute stream packet transmission processing for transmitting stream data and transmission method determination processing for determining a transmission method for transmitting a part of the stream data as an estimation packet sequence.

  According to the present invention, it is possible to estimate a usable network bandwidth with high accuracy in stream distribution.

It is a block diagram which shows an example of a structure of the stream delivery system of the 1st Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream delivery apparatus of the 1st Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream receiver of the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the stream delivery apparatus of the 1st Embodiment of this invention. It is a flowchart which shows the detailed operation | movement of the transmission method determination means of the 1st Embodiment of this invention. It is a figure which shows an example of the packet produced | generated by the packet production | generation means of the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the stream receiver of the 1st Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream delivery apparatus of the 2nd Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream receiver of the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement at the time of the feedback reception of the stream delivery apparatus of the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the stream receiver of the 2nd Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream delivery system of the 3rd Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream delivery apparatus of the 3rd Embodiment of this invention. It is a block diagram which shows an example of a structure of the stream receiver of the 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of the stream delivery apparatus of the 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of the stream receiver of 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, equivalent components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
(First embodiment)
A configuration in the present embodiment will be described.

  FIG. 1 is a block diagram showing an example of the configuration of the stream distribution system according to the first embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  A stream distribution system 400 according to this embodiment includes a stream distribution device 100 that distributes stream data, a stream reception device 200 that receives stream data, and a network 300. The stream distribution device 100 and the stream reception device 200 are connected via the network 300. In the stream distribution system 400, a plurality of stream receiving apparatuses 200 may be connected to one stream distribution apparatus 100. Further, the stream distribution system 400 may have a bidirectional configuration in which stream data is distributed from the stream reception device 200 to the stream distribution device 100. The network 300 is the Internet, a mobile network, an in-house network (intranet), a home LAN (Local Area Network), or a combination of these.

  The configuration of the stream distribution device 100 will be described.

  FIG. 2 is a block diagram illustrating an example of the configuration of the stream distribution device 100 according to the first embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream distribution apparatus 100 includes a parameter setting unit 110, a stream data input unit 120, a transmission method determination unit 130, a packet specification determination unit 140, a packet generation unit 150, and a stream packet transmission unit 160.

  The parameter setting unit 110 accepts the setting by the user of parameters used for the determination in the transmission method determination unit 130 and the packet specification determination unit 140. The type and usage method of parameters will be described later.

  The stream data input unit 120 inputs stream data to be transmitted. The stream data includes information such as image data of one video frame, audio data for a predetermined time, or sensor information for a predetermined time. The stream data input unit 120 inputs such information from a camera, a microphone, a sensor (none of which is shown), or the like. The stream data may be encoded (compressed). In that case, the stream data input means 120 inputs encoded stream data from an encoder (not shown).

  The transmission method determining means 130 receives the data size of the stream data from the stream data input means 120 and the parameter for determination from the parameter setting means 110, and determines the transmission method of the stream data from these information. Here, the transmission method includes a packet train transmission method and a transmission method using a normal packet sequence for the throughput measurement method (hereinafter referred to as “normal packet transmission method”). In a normal packet transmission method, stream data is divided into packets having a size equal to or smaller than the MTU (Maximum Transfer Unit) of the network, and transmitted without an interval.

  The packet specification determination unit 140 determines the packet size and transmission time of each packet when transmitting the stream data based on the transmission method determination by the transmission method determination unit 130.

  The packet generation unit 150 receives the stream data from the stream data input unit 120, divides the stream data so as to have the packet size determined by the packet specification determination unit 140, and adds a header to generate a packet.

  The stream packet transmission unit 160 receives the packet from the packet generation unit 150 and transmits the packet to the stream reception device 200 at a designated time.

  The configuration of the stream receiving device 200 will be described.

  FIG. 3 is a block diagram illustrating an example of a configuration of the stream reception device 200 according to the first embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream receiving apparatus 200 includes a stream packet receiving unit 210, a stream data processing unit 220, and an available bandwidth estimation unit 230.

  The stream packet receiving unit 210 receives the packet transmitted by the stream distribution apparatus 100 and notifies the stream data processing unit 220 and the usable bandwidth estimation unit 230 of the received packet information.

  The stream data processing unit 220 processes the stream data included in the packet received by the stream packet receiving unit 210. For example, when the stream data includes a video frame, the stream data processing unit 220 outputs the stream data to a display device (not shown). For example, when the stream data includes an audio frame, the stream data processing unit 220 outputs the stream data to a speaker (not shown). Further, the stream data processing means 220 may output the stream data to a storage device (not shown). If the stream data has been encoded, the stream data processing means 220 may output the stream data to a decoding device (not shown).

  The available bandwidth estimation unit 230 estimates the available bandwidth in the network 300 based on the packet size and reception time of the packet including the stream data notified from the stream packet reception unit 210.

  Next, the operation in this embodiment will be described.

  The operation of the stream distribution device 100 will be described.

  FIG. 4 is a flowchart illustrating the operation of the stream distribution device 100 according to the first embodiment of this invention. Note that the flowchart shown in FIG. 4 and the following description are merely examples, and the processing order may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  First, the transmission method determination unit 130 and the packet specification determination unit 140 receive parameter settings from the parameter setting unit 110 (step S401).

  Next, the stream data input means 120 inputs stream data (step S402).

  Subsequently, the transmission method determination unit 130 determines the transmission method of the input stream data based on the data size of the stream data received from the stream data input unit 120 and the parameter settings received from the parameter setting unit 110. (Step S403). Here, the transmission method is either a normal packet transmission method or a packet train transmission method.

  Subsequently, the packet specification determination unit 140 determines the packet specifications (packet size and transmission time) in the transmission of the data link frame based on the transmission method determined by the transmission method determination unit 130 (step S404).

  Subsequently, the packet generation unit 150 divides the stream data based on the packet specification determined by the packet specification determination unit 140, and generates a packet (step S405).

  Subsequently, the stream packet transmission unit 160 transmits the packet generated by the packet generation unit 150 to the stream reception device 200 (step S406).

  Subsequently, the stream data input unit 120 determines whether or not stream data is input (step S407). The stream data input unit 120 repeats the processing from step S402 to step S406 while the stream data is input (step S407: Yes). When the input of the stream data is completed (step S407: No), the stream data input unit 120 ends the process.

  The detailed operation of the transmission method determining means 130 will be described.

  FIG. 5 is a flowchart showing a detailed operation of the transmission method determination unit 130 according to the first embodiment of this invention. Note that the flowchart shown in FIG. 5 and the following description are merely examples, and the processing order may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  If the data size of the input stream data is equal to or larger than the predetermined threshold (step S4031: Yes), the transmission method determination unit 130 determines to use the normal packet transmission method (step S4032). If the data size is less than the predetermined threshold (step S4031: No), the transmission method determining unit 130 determines to use the packet train transmission method (step S4033).

  Note that the threshold value in step S4031 is determined from the relationship between the data size of the stream data and the MTU, for example. As described above, when the data size of the stream data is equal to or smaller than the MTU, the stream data is transmitted in one packet, and thus the time taken for reception cannot be acquired. Therefore, the threshold value in step S4031 may be set to MTU + 1. However, since the measurement error of the available bandwidth increases when the number of packets is small, the threshold value in step S4031 may be set to MTU × a + 1 (a is a natural number).

  The detailed operation of the packet specification determining unit 140 will be described.

  When the normal packet transmission method is selected, the packet specification determination unit 140 sets the MTU as the packet size, and determines the packet specification so that all packets are transmitted immediately at the transmission time.

  For example, Ethernet (registered trademark) is used for the data link layer, IPv4 (Internet Protocol version 4) for the network layer, UDP (User Datagram Protocol) for the transport layer, and RTP (Real-time Transport Protocol) for the application layer The case where it will be described. The MTU of Ethernet is 1500 bytes, and the header sizes (not including options) of IPv4, UDP, and RTP are 20, 8, and 12 bytes, respectively. Therefore, the packet specification determining unit 140 determines the packet size so that the stream data is divided into 1460 bytes (= 1500− (20 + 8 + 12)) to generate an RTP packet of 1500 bytes. Note that the packet specification determining unit 140 can identify RTP packets including different parts of a specific series of stream data. For example, the packet specification determining unit 140 sets the same value in a time stamp field (hereinafter simply referred to as “time stamp”) of an RTP packet including different portions of a specific series of stream data. Alternatively, the packet specification determination unit 140, for example, sets the Marker bit of the RTP header of the last RTP packet including a different part of a specific series of stream data to ON. For example, by these methods, it is possible to identify that an RTP packet including a different part of a specific series of stream data is a packet included in one packet train.

  On the other hand, when the packet train transmission method is selected, the packet specification determination unit 140 determines the packet specifications so as to satisfy a predetermined constraint condition.

The constraint condition is, for example, a logical product of the following constraint conditions.
Restriction condition 1: The data size of stream data included in one packet train is equal to or smaller than the data size of stream data to be transmitted. However, the payload of the data link frame that is actually transmitted may include some dummy data in addition to the stream data. Further, the stream data remaining when configuring the packet train packet may be transmitted as a normal packet that is not a packet train packet.
Restriction 2: Transmission of the current stream data is completed before the next stream data is input.
Restriction condition 3: The lower limit of the available bandwidth that can be estimated is equal to or lower than a predetermined lower limit.
Restriction condition 4: The upper limit of the available bandwidth that can be estimated is greater than or equal to a predetermined upper limit.

  The determination of the packet specification by the packet specification determination unit 140 is formulated as an optimization problem that maximizes or minimizes the objective function under the above-described constraints. The objective function is, for example, a function representing maximization of the resolution of the available bandwidth estimation value, or a function representing minimization of a step size of the usable bandwidth estimation value having a meaning corresponding to the aforementioned function. Note that the constraint condition and the objective function can be interchanged. For example, the optimization problem described above is based on the “upper limit of the estimable available bandwidth” under the constraint that “the resolution is equal to or higher than a predetermined target value” in which the objective function and the constraint 4 are replaced. It is replaced by an optimization problem that maximizes the objective function of value.

  Next, a specific packet specification (packet size and transmission time) determination method will be described by taking as an example the case where the packet train measurement method of Patent Document 1 is used.

In the packet train measurement method of Patent Document 1, the packet train to be transmitted is
-Packet size of the first packet: P (1) [bytes]
-Packet size increment: ΔP [bytes]
-Number of packets: N
-Packet interval: T [seconds]
It is characterized using the following four types of parameters. The packet size of the i-th (2 <= i <= N) packet is P (i) and the transmission time is t (i). P (i) = P (1) + (i-1 ) ΔP, t (i) = t (1) + (i−1) T. Note that the lower limit value of the usable bandwidth that can be estimated (unit: bps (Bit Per Second)) is 8P (1) / T, and the upper limit value of the usable bandwidth that can be estimated (unit: bps) is 8 ( P (1) + ΔP (N−1)) / T, and the resolution is ΔP / T. Note that the lower limit value of the available bandwidth that can be estimated is detected when the delay in receiving the second packet is increased compared to the delay in receiving the first packet. In this case, a packet with a packet size P (1) [bytes] could be received at time T [seconds], but a packet with a packet size P (2) [bytes] could not be received at time T [seconds]. It corresponds to. In other words, in this case, the packet can be received at the bit rate 8P (1) / T [bps], but this is equivalent to the case where the packet cannot be received at the bit rate 8P (2) / T [bps]. The lower limit value of the available bandwidth is 8P (1) / T [bps].

  On the other hand, the upper limit value of the available bandwidth that can be estimated is detected when the delay in receiving the Nth packet does not increase compared to the delay in receiving the (N-1) th packet. This case corresponds to a case where a packet having a packet size P (N) [bytes] can be received at time T [seconds]. That is, in this case, the bit rate of 8P (N) / T = 8 (P (1) + ΔP (N−1)) [bps] corresponds to the case where a packet can be received, and the upper limit of the usable bandwidth that can be estimated. The value is 8 (P (1) + ΔP (N−1)) / T [bps]. The step size of the available bandwidth that can be estimated is equal to the bit rate difference ΔP / T between adjacent packets.

In this specific example, four types of parameters and the data size of stream data to be transmitted: S [bytes]
-Lower limit value of available bandwidth that can be estimated: Bmin [bps]
-Estimated upper limit of available bandwidth: Bmax [bps]
-Upper limit of packet train transmission time: f [seconds]
Is given. The lower limit value Bmin of the usable bandwidth that can be estimated and the upper limit value Bmax of the usable bandwidth that can be estimated are acquired by the parameter setting unit 110. Further, the upper limit value f of the packet train transmission time and the value of the data size S of the stream data to be transmitted are determined in advance. For example, when the stream data is a video frame, the packet train needs to be transmitted within the transmission interval of each video frame. That is, the upper limit f of the packet train transmission time is determined in advance as the reciprocal of the frame rate (f is 0.2 seconds if the frame rate is 5 fps (frames per second), and f is 0.1 seconds if the frame rate is 10 fps). Is done. For example, the value of the data size S of the stream data to be transmitted is determined in advance in relation to the data size of the video frame.

  Therefore, the above optimization problem for maximizing the resolution (minimizing the step size) while satisfying the constraint conditions 1 to 4 is formulated as follows. Hereinafter, in order to simplify the description, the packet size of the packet and the size of the payload will be described as being identical in the constraint condition 1. However, the constraint condition 1 may be formulated in consideration of the difference between the packet size of the packet and the payload size. If a slight error is allowed, it is possible to equate the packet size of the packet with the size of the payload.

minimize ΔP / T
subject to N (P (1) + ΔP (N−1) / 2) <= S (Constraint 1)
(N-1) T <= f (Constraint 2)
8P (1) / T <= Bmin (Constraint 3)
8 (P (1) + ΔP (N−1)) / T> = Bmax (Constraint 4)
In Constraint 1, the data size of stream data included in one packet train is P (1) + P (2) +... + P (N), and P (i) = P (1) + (I-1) It is obtained by substituting ΔP. Further, in the constraint condition 2, since the time required for transmission of the stream data itself is sufficiently smaller than the packet interval T, the time required for transmission of all the packets included in one packet train is the interval between the packets. Is multiplied by the packet interval T.

  The packet specification determination unit 140 causes the packet generation unit 150 to generate a packet train characterized by the four parameters P (1), ΔP, N, and T obtained by solving this optimization problem.

  Next, an example of a solution for the optimization problem will be described. Of the above four parameters, P (1), ΔP, and N are integers, and T is a real number. Therefore, first, the packet specification determining means 140 obtains the maximum T satisfying the constraint condition for the combination of P (1), ΔP, and N, and ΔP / T for this T. Note that there may be no T satisfying the constraint condition. Next, the packet specification determining means 140 determines the combination of parameters P (1), ΔP, N, and T that minimize the obtained ΔP / T as the packet specification. Note that the solution of the optimization problem in the present embodiment is not limited to the above-described solution. However, since the solution itself of the optimization problem is widely known, it will not be described in detail.

  The detailed operation of the packet generator 150 will be described.

  When the normal packet transmission method is selected, for example, the packet generation unit 150 divides the stream data into units of 1460 bytes as described above, adds various headers, and transmits the packet as a 1500-byte IPv4 packet. At this time, the packet generation means 150 transmits the next packet immediately after the transmission of the immediately preceding packet is completed without leaving an interval between the packets. On the other hand, when the packet train transmission method is selected, the packet generation means 150 is based on the packet specification (combination of parameters P (1), ΔP, N, and T) determined by the packet specification determination means 140. To generate a packet.

  FIG. 6 is a diagram illustrating an example of stream data division by the packet generation unit 150 according to the first embodiment of this invention. In FIG. 6, “input” indicates stream data to be transmitted, and “output” indicates stream data divided for transmission. The number indicates the data size of the stream data.

  For example, the packet generation unit 150 converts the stream data to be transmitted with S = 7500 bytes into a packet train according to the packet specifications (P (1) = 500 bytes, ΔP = 50 bytes, N = 10, T = 0.005 seconds). Divide into It is assumed that the packet train transmission start time is t0.

  First, the packet generation unit 150 extracts P (1) (= 500) bytes from the beginning of stream data to be transmitted, adds various headers to generate an RTP packet, and sets t0 as the transmission time of this packet. . Next, the packet generation means 150 extracts the next P (1) + ΔP (= 550) bytes from the stream data, generates an RTP packet, and sets t0 + T as the transmission time. Subsequently, the packet generation unit 150 repeats such processing, and the Nth RTP packet (data size: P (1) + (N−1) ΔP = 950 bytes, transmission time: t0 + (N−1)). T). Finally, the packet generator 150 generates an RTP packet including the remaining 250 bytes of stream data. The packet generator 150 sets the time immediately after the transmission time of the Nth packet as the transmission time of the last RTP packet.

  Note that the packet generation means 150 may use the Extension bit of the RTP header defined in RTP in order to distinguish packets generated by the normal packet transmission method or packet train transmission method. Specifically, for example, the packet generation unit 150 sets the Extension bit to 0 in the case of the normal packet transmission method, and sets the Extension bit to 1 in the case of the packet train transmission method. The Extension bit is a flag indicating that an extension header exists immediately after a standard RTP header of 12 bytes. The packet generator 150 may store information (such as a packet transmission time) used for estimating the available bandwidth in the extension header.

  A method for generating an RTP packet in a more specific example will be described.

  In this specific example, the stream data is H.264 of ITU-T (International Telecommunication Union Telecommunication Standardization Sector). H.264 format or H.264 format. This is video frame data encoded in the H.265 format. H. H.264 format and H.264 format. The minimum unit of the H.265 format stream is called a NAL (Network Abstraction Layer) unit. Each video frame includes one or more NAL units. H. using RTP The H.264 stream transmission protocol is defined in RFC (Request for Comments) 6184 of the Internet Engineering Task Force (IETF). In RFC6184, normally, one RTP packet stores one NAL unit. However, RFC6184 defines “Fragmentation Unit” in which one NAL unit is divided into a plurality of RTP packets and “Aggregation Packet” in which one RTP packet includes a plurality of NAL units. By using “Fragmentation Unit” or “Aggregation Packet”, it is possible to transmit a packet train as a stream compliant with RFC6184. Here, H. H.264 has been described. A similar method can be used in H.265.

  The operation of the stream receiving device 200 will be described.

  FIG. 7 is a flowchart showing an operation of the stream reception device 200 according to the first embodiment of this invention. Note that the flowchart shown in FIG. 7 and the following description are merely examples, and the processing order may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  First, the stream packet receiving unit 210 receives a packet including stream data distributed from the stream distribution apparatus 100, and notifies the stream data processing unit 220 and the available bandwidth estimation unit 230 of the received packet information (step S701). ).

  Next, the stream data processing unit 220 processes the stream data included in the packet received by the stream packet receiving unit 210 (step S702).

  Subsequently, the available bandwidth estimation unit 230 estimates the available bandwidth in the network 300 based on the data size and reception time of the packet including the stream data notified from the stream packet reception unit 210 (step S703).

  Subsequently, the stream packet receiving unit 210 determines whether or not stream data has been received (step S704). The stream packet receiving unit 210 repeats the processing from step S701 to step S703 while stream data is being received (step S704: Yes). When the stream packet receiving unit 210 finishes receiving the stream data (step S704: No), the process ends.

  The detailed operation of the available bandwidth estimation unit 230 will be described.

  For example, the available bandwidth estimation unit 230 refers to an RTP header in the received RTP packet and determines whether the RTP packet is transmitted by a normal packet transmission method or a packet train transmission method.

  When transmitted by a normal packet transmission method, the available bandwidth estimation unit 230 acquires the reception start time and reception completion time and the data size of the stream data of the packet including each stream data. The reception start time is, for example, the time when a packet including a certain RTP time stamp is first received. The reception completion time is, for example, the time when a packet whose marker bit is ON among packets including a certain RTP time stamp is received. The data size of the stream data is, for example, the total payload length of RTP packets including the same RTP time stamp. The available bandwidth estimation unit 230 calculates “data size / (reception completion time−reception start time)” after completion of reception of a series of stream data, and uses the result as an estimated value of the available bandwidth.

  When transmitted by the packet train transmission method, the available bandwidth estimation unit 230 acquires the reception time of each packet included in one packet train. When the available bandwidth estimation unit 230 detects completion of reception of a series of packet trains with reference to an extension header or the like, the available bandwidth estimation unit 230 estimates the available bandwidth. Note that the available bandwidth estimation method is an available bandwidth estimation method in the packet train measurement method of Patent Literature 1, Non-Patent Literature 2, or Non-Patent Literature 3, or the like.

  As described above, in the stream distribution system 400 of this embodiment, the packet generation unit 150 of the stream distribution device 100 generates a measurement packet from the stream data to be transmitted. That is, since the stream distribution system 400 transmits the stream data that should be transmitted originally so as not to adversely affect the estimation of the available bandwidth, no new packet is added and no delay is caused thereby. Therefore, the estimation accuracy of the usable bandwidth is high. In addition, the available bandwidth estimation unit 230 of the stream reception device 200 estimates the available bandwidth based on the received measurement packet. Therefore, the stream distribution system 400 of the present embodiment has an effect that the available network bandwidth can be estimated with high accuracy in stream distribution.

  In the stream distribution system 400 of the present embodiment, the packet specification determination unit 140 of the stream distribution device 100 determines the specification of the measurement packet for estimating the available bandwidth with high accuracy by solving the optimization problem. To do. In addition, the available bandwidth estimation unit 230 of the stream reception device 200 estimates the available bandwidth with a predetermined accuracy based on the received measurement packet. Therefore, the stream distribution system 400 of the present embodiment has an effect that the available network bandwidth can be estimated with high accuracy in stream distribution.

In the stream distribution system 400 of the present embodiment, when the data size of the stream data is less than a predetermined threshold, the transmission method determination unit 130 of the stream distribution device 100 transmits the stream data using the packet train transmission method. To do. As a result, measurement errors in the throughput measurement method are suppressed. Further, in the stream distribution system 400 of this embodiment, when the data size of the stream data is equal to or larger than a predetermined threshold, the transmission method determination unit 130 of the stream distribution device 100 uses the normal packet transmission method to transmit the stream data. Send. In this case, since measurement data having a sufficient data size is used, measurement errors in the usable bandwidth estimation method are suppressed. Therefore, the stream distribution system 400 of the present embodiment has an effect that the available network bandwidth can be estimated with high accuracy in stream distribution.
(Second Embodiment)
Next, a stream distribution system according to the second embodiment of the present invention based on the above-described stream distribution system 400 according to the first embodiment of the present invention will be described. In the stream distribution system of the present embodiment, the stream reception device feeds back the estimation result of the available bandwidth to the stream distribution device, and the stream distribution device controls the bit rate of the stream data based on the feedback result. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  A configuration in the present embodiment will be described.

  A stream distribution system 405 (not shown) of the present embodiment includes a stream distribution device 105, a stream reception device 205, and a network 300. The operations of the stream distribution device 105 and the stream reception device 205 are different from the operations of the stream distribution device 100 and the stream reception device 200 of the first embodiment of the present invention, respectively. The other configuration of the stream distribution system 405 is the same as the configuration of the stream distribution system 400 according to the first embodiment of this invention.

  The configuration of the stream distribution device 105 will be described.

  FIG. 8 is a block diagram illustrating an example of the configuration of the stream distribution device 105 according to the second embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream distribution apparatus 105 of the present embodiment includes a feedback reception unit 170, a bit rate control unit 180, and a stream data generation unit 190 in addition to the components of the stream distribution apparatus 100 of the first embodiment. In addition, the parameter setting unit 110 and the stream data input unit 120 of the stream distribution device 100 according to the first embodiment are replaced with a parameter setting unit 115 and a stream data input unit 125, respectively.

  The feedback receiving unit 170 receives information on the estimated value of the available bandwidth from the stream receiving device 205.

  The bit rate control means 180 determines the bit rate for generating the stream data based on the information on the available band estimation value received from the feedback receiving means 170.

  The stream data generation unit 190 generates stream data at the bit rate determined by the bit rate control unit 180. For example, when the stream data is video, the stream data generation unit 190 receives a video frame from a camera (not shown), The stream data is encoded using a codec such as H.264 so that the determined bit rate is obtained.

  The parameter setting unit 115 receives the estimated value of the available bandwidth from the feedback receiving unit 170.

  The stream data input unit 125 inputs the stream data to be transmitted from the stream data generation unit 190.

  The other configuration of the stream distribution device 105 is the same as the configuration of the stream distribution device 100 of the first embodiment.

  The configuration of the stream receiving device 205 will be described.

  FIG. 9 is a block diagram illustrating an example of a configuration of the stream reception device 205 according to the second embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream reception device 205 according to the second embodiment of the present invention includes feedback transmission means 240 in addition to the components of the stream reception device 200 according to the first embodiment. In addition, the available bandwidth estimation unit 230 of the stream receiving apparatus 200 according to the first embodiment is replaced with an available bandwidth estimation unit 235.

  The available bandwidth estimation unit 235 notifies the feedback transmission unit 240 of the estimated value of the available bandwidth.

  The feedback transmission unit 240 transmits (feeds back) the estimated value of the available bandwidth estimated by the available bandwidth estimation unit 235 to the stream distribution device 105.

  The other configuration of the stream receiving device 205 is the same as the configuration of the stream receiving device 200 of the first embodiment.

  Next, the operation in this embodiment will be described.

  The operation of the stream distribution device 105 will be described.

  FIG. 10 is a flowchart illustrating an operation at the time of feedback reception from the stream reception device 205 of the stream distribution device 105 according to the second embodiment of this invention. Note that the flowchart shown in FIG. 10 and the following description are merely examples, and the processing order and the like may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  First, the feedback receiving unit 170 receives feedback of the estimated value of the available bandwidth from the stream receiving device 205, and notifies the parameter setting unit 115 and the bit rate control unit 180 of the received information (step S1001).

  Next, the parameter setting unit 115 changes the parameter used for each determination in the transmission method determination unit 130 and the packet specification determination unit 140 based on the estimated value of the available bandwidth notified from the feedback reception unit 170. (Step S1002).

  Subsequently, the bit rate control unit 180 determines the bit rate of the stream data to be transmitted based on the estimated value of the available bandwidth received from the feedback receiving unit 170 (step S1003).

  Finally, the stream data generation unit 190 generates stream data having the bit rate determined by the bit rate control unit 180 (step S1004).

  The detailed operation of the parameter setting unit 115 will be described.

  For example, the parameter setting unit 115 may change the threshold value for determining whether to use the packet train transmission method or the normal packet transmission method (step S4031 in FIG. 5) based on the estimated value of the available bandwidth. Good. As described above, in the throughput measurement method, if the “time required for reception” is short, the measurement error is large. When the threshold is fixed, if the available bandwidth is large, the “time required for reception” is shortened, and the measurement accuracy is lowered. Therefore, the parameter setting unit 115 reduces the measurement error by increasing the threshold when the estimated value of the available bandwidth is large and decreasing the threshold when the estimated value of the available bandwidth is small. Specifically, when the estimated value of the available bandwidth is b and the threshold of “time taken for reception” is th, the parameter setting unit 115 uses the packet train transmission method or the normal packet transmission method. Is set to b × th.

  Further, the parameter setting unit 115 may change the lower limit value Bmin and the upper limit value Bmax of the available bandwidth that can be estimated based on the estimated value of the available bandwidth, for example. Usually, the lower limit Bmin is set to a sufficiently small value, and the upper limit Bmax is set to a sufficiently large value. However, the resolution can be improved by increasing the lower limit value Bmin or decreasing the upper limit value Bmax. For example, when the lower limit Bmin is increased, the constraint condition 3 is relaxed and the packet interval T can be increased, so that the objective function ΔP / T can be reduced (that is, the resolution can be increased). Further, when the upper limit value Bmax is reduced, the constraint condition 4 is relaxed, the packet size increment ΔP can be reduced, and the packet interval T can be increased. Therefore, the objective function ΔP / T can be reduced. For example, the parameter setting unit 115 may perform control to suppress the bit rate of the stream data to be transmitted to a maximum of twice the previous bit rate. When this control is performed, the upper limit value Bmax is suppressed to twice the bit rate of the stream data, so that the resolution can be improved as described above.

  The detailed operation of the bit rate control means 180 will be described.

  For example, the bit rate control unit 180 may determine the latest available bandwidth estimation value received from the feedback reception unit 170 as the bit rate of the generated stream data. Although the available bandwidth varies depending on factors such as the degree of congestion of the network 300, the stream distribution system 405 can change the bit rate in response to the variation, so that the available bandwidth of the network 300 can be used effectively. Alternatively, the bit rate control unit 180 converts, for example, the result of performing filtering such as moving average on the time series of the estimated value of the available bandwidth received from the feedback receiving unit 170 to the bit rate of the generated stream data. You may decide. Alternatively, for example, the bit rate control unit 180 obtains the result of performing filtering such as moving average on the available bandwidth or the time series of the estimated value of the available bandwidth received from the feedback receiving unit 170 as α (α May be determined as the bit rate of the stream data to be generated.

  A detailed operation of the stream data generation unit 190 will be described. For example, when the stream data is video, the stream data generation unit 190 designates the bit rate determined by the bit rate control unit 180 to the encoder (not shown). Alternatively, when the stream data is audio, the stream data generation unit 190 specifies the bit rate determined by the bit rate control unit 180 to the encoder for the type of codec that can specify the bit rate. On the other hand, the stream data generation means 190 switches the codec type for the codec type for which the bit rate cannot be specified when the stream data is audio. In this case, the stream data generation unit 190 selects a codec type that can specify a bit rate that is equal to or lower than the bit rate determined by the bit rate control unit 180. Further, when the stream data is sensor data or the like, the stream data generation unit 190 thins out the data (discards the data without transmitting it), thereby obtaining the bit rate determined by the bit rate control unit 180. The stream data may be generated.

  Other operations of the stream distribution apparatus 105 of the present embodiment are the same as the operations of the stream distribution apparatus 100 of the first embodiment.

  The operation of the stream receiving device 205 will be described.

  FIG. 11 is a flowchart illustrating the operation of the stream reception device 205 according to the second embodiment of this invention. Note that the flowchart shown in FIG. 11 and the following description are merely examples, and the processing order and the like may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  The feedback transmission unit 240 feeds back the estimated value of the available bandwidth estimated by the available bandwidth estimation unit 235 to the stream distribution device 105 (step S1105).

  Other operations of the stream receiving device 205 of the present embodiment are the same as the operations of the stream receiving device 200 of the first embodiment.

  As described above, in the stream distribution system 405 of the present embodiment, the stream distribution device 105 includes the function of the stream distribution device 100 of the first embodiment of the present invention. In the stream distribution system 405 of the present embodiment, the stream receiving device 205 includes the function of the stream receiving device 200 of the first embodiment of the present invention. Therefore, the stream distribution system 405 of the present embodiment has the same effect as the stream distribution system 400 of the first embodiment of the present invention.

In the stream distribution system 405 of the present embodiment, the feedback transmission unit 240 of the stream reception device 205 feeds back the estimation result of the available bandwidth to the stream distribution device 105. Further, in the stream distribution system 405 of the present embodiment, the feedback receiving unit 170 of the stream distribution apparatus 105 determines the bit rate of stream data to be transmitted based on the fed back available band estimation result. Therefore, the stream distribution system 405 of the present embodiment has an effect that the available network bandwidth can be effectively used in stream distribution.
(Third embodiment)
Next, a stream distribution system according to a third embodiment of the present invention having the minimum configuration of the present invention will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  A configuration in the present embodiment will be described.

  FIG. 12 is a block diagram illustrating an example of the configuration of the stream distribution system according to the third embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream distribution system 406 of this embodiment includes a stream distribution device 106, a stream reception device 206, and a network 300.

  The configuration of the stream distribution device 106 will be described.

  FIG. 13 is a block diagram illustrating an example of the configuration of the stream distribution device 106 according to the third embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream distribution device 106 includes a transmission method determination unit 136 and a stream packet transmission unit 166.

  The transmission method determination unit 136 determines a transmission method for transmitting a part of the stream data as an estimation packet sequence. Note that the transmission method may include a packet train transmission method, a normal packet transmission method, and the like. Further, when the transmission method is a packet train transmission method, the transmission method determination means 136 maximizes an objective function having a positive correlation with the accuracy of estimation after satisfying a given constraint condition, or The packet specifications may be determined so as to minimize an objective function that has a negative correlation with the accuracy of the estimation. The constraint conditions may include the size of stream data, the lower and upper limits of the available bandwidth that can be estimated, the upper limit of the transmission time of the packet train, and the like. The packet specification may include the size and transmission time of each packet included in the packet train. The packet specification may be a specification in which the size of each packet included in the estimation packet sequence is increased in the order of appearance and the transmission cycle is made constant. The packet specification may include the size of the packet that appears first in the packet train, the size increase between two adjacent packets, the number of packets, the packet transmission period, and the like. Further, the transmission method determining unit 136 may determine the transmission method depending on whether or not the data size of the stream data to be transmitted is less than a predetermined threshold.

  The stream packet transmission unit 166 transmits the stream data to the stream reception device 206 according to the transmission method determined by the transmission method determination unit 136. Note that the stream packet transmission unit 166 may change the parameter value of the stream distribution device 106 based on the estimation result when the estimation result of the available bandwidth is fed back from the stream reception device 206. The parameter may include a parameter included in the above-described constraint condition, the above-described threshold value, a bit rate of stream data to be transmitted, and the like.

  The configuration of the stream receiving device 206 will be described.

  FIG. 14 is a block diagram illustrating an example of the configuration of the stream reception device 206 according to the third embodiment of this invention. In addition, the direction of the arrow in a drawing shows an example and does not limit the direction of the signal between blocks.

  The stream reception device 206 includes a stream packet reception unit 216 and an available bandwidth estimation unit 236.

  The stream packet receiving unit 216 receives the stream data and the estimation packet sequence.

  The available bandwidth estimation means 236 estimates the available bandwidth of the network based on the received estimation packet sequence. Note that the estimation method may include a packet train measurement method, a throughput measurement method, and the like. Note that the available bandwidth estimation unit 236 may feed back the estimation result of the available bandwidth to the stream distribution device 106.

  Next, the operation in this embodiment will be described.

  The operation of the stream distribution device 106 will be described.

  The transmission method determining unit 136 determines the transmission method of the input stream data based on the data size of the stream data to be transmitted and a predetermined parameter set in advance (step S1503).

  The stream packet transmitting unit 166 transmits the stream data to the stream receiving device 206 according to the transmission method determined by the transmission method determining unit 136 (step S1506).

  FIG. 15 is a flowchart illustrating the operation of the stream distribution device 106 according to the third embodiment of this invention. Note that the flowchart shown in FIG. 15 and the following description are merely examples, and the processing order may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  The operation of the stream receiving device 206 will be described.

  FIG. 16 is a flowchart illustrating the operation of the stream reception device 206 according to the third embodiment of this invention. Note that the flowchart shown in FIG. 16 and the following description are examples, and the processing order may be changed, the processing may be returned, or the processing may be repeated depending on the processing that is appropriately obtained.

  The stream packet receiving unit 216 receives the estimation packet sequence distributed from the stream distribution device 106, and notifies the usable bandwidth estimation unit 236 of the information (including the data size and the reception time) of the received estimation packet sequence. (Step S1601).

  The available bandwidth estimation unit 236 estimates the available bandwidth in the network 300 based on the information of the estimation packet sequence notified from the stream packet reception unit 216 (step S1603).

  As described above, in the stream distribution system 406 of the present embodiment, the transmission method determination unit 136 of the stream distribution apparatus 106 causes the stream packet transmission unit 166 to transmit the measurement packet generated from the stream data to be transmitted. That is, in the stream distribution system 406, measurement data different from the stream data to be transmitted is not used, so that the influence of the available bandwidth estimation on the throughput of the stream data is suppressed, and as a result, the estimation accuracy of the available bandwidth is reduced. Is expensive. Further, the available bandwidth estimation unit 236 of the stream receiving device 206 estimates the available bandwidth based on the received measurement packet. Therefore, the stream distribution system 406 of the present embodiment has an effect that the available network bandwidth can be estimated with high accuracy in stream distribution.

  In addition, the stream distribution device and the stream reception device according to each embodiment of the present invention described above may be realized by a dedicated device, but may also be realized by a computer (information processing device). In this case, the computer reads a software program stored in a memory (not shown) to a CPU (Central Processing Unit, not shown), and executes the read software program on the CPU to obtain an execution result. For example, output to the user interface. In the case of each of the embodiments described above, the software program includes, as described above, each unit of the stream distribution device 100 illustrated in FIG. 2, each unit of the stream reception device 200 illustrated in FIG. 3, and illustrated in FIG. It is only necessary to have a description that can realize the functions of the respective means of the stream distribution apparatus 105 and the respective means of the stream reception apparatus 205 shown in FIG. However, it is assumed that each means of the stream distribution device 100, the stream distribution device 105, the stream reception device 200, and the stream reception device 205 includes hardware as appropriate. In such a case, the software program (computer program) can be regarded as constituting the present invention. Furthermore, a computer-readable storage medium storing such a software program can also be understood as constituting the present invention.

  The present invention has been exemplarily described with the above-described embodiments and modifications thereof. However, the technical scope of the present invention is not limited to the scope described in the above-described embodiments and modifications thereof. It will be apparent to those skilled in the art that various modifications and improvements can be made to such embodiments. In such a case, new embodiments to which such changes or improvements are added can also be included in the technical scope of the present invention. This is clear from the matters described in the claims.

A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
Stream data receiving means for receiving stream data and an estimation packet sequence, and usable bandwidth estimation means for estimating an available bandwidth of the network based on the received estimation packet sequence. A stream packet transmitting means for transmitting;
A stream distribution apparatus comprising: a transmission method determination unit that determines a transmission method for transmitting a part of the stream data as the estimation packet sequence.
(Appendix 2)
The stream distribution apparatus according to appendix 1, further comprising packet specification determining means for determining the size and transmission time of each packet included in the estimation packet sequence so as to satisfy given constraint conditions.
(Appendix 3)
The packet specification determining means maximizes the first objective function having a positive correlation with the accuracy of the estimation or satisfies the size and the transmission time while satisfying the constraint condition, or The stream delivery apparatus according to appendix 2, wherein the second objective function having the correlation of the second objective function is determined to be minimized.
(Appendix 4)
The stream distribution apparatus according to any one of appendices 1 to 3, wherein the size of each packet included in the estimation packet sequence increases with the order of appearance, and the transmission cycle is constant.
(Appendix 5)
The packet specification deciding means, from the input parameter including the size of the stream data, from the estimation packet sequence, the size of the packet that appears first, the size increment between two adjacent packets, the number of packets, And the output parameter including the packet transmission cycle is determined. The stream distribution device according to appendix 2 or appendix 3.
(Appendix 6)
The stream distribution apparatus according to appendix 5, wherein the input parameters include a lower limit value and an upper limit value of an available bandwidth that can be estimated, and an upper limit value of a transmission time of a packet sequence.
(Appendix 7)
A stream packet transmitting means for transmitting stream data; and a transmission method determining means for determining a transmission method for transmitting a part of the stream data as an estimation packet sequence. Stream packet receiving means for receiving a packet sequence;
A stream receiving device comprising: an available bandwidth estimating unit that estimates an available bandwidth of a network based on the received estimation packet sequence.
(Appendix 8)
A stream receiving device including stream packet receiving means for receiving stream data and an estimation packet sequence; and an available bandwidth estimation means for estimating an available bandwidth of the network based on the received estimation packet sequence;
A stream distribution apparatus comprising: stream packet transmission means for transmitting the stream data; and a transmission method determination means for determining a transmission method for transmitting a part of the stream data as the estimation packet sequence. Stream delivery system.
(Appendix 9)
Determining a transmission method for transmitting a part of the stream data as an estimation packet sequence, transmitting the stream data,
Receiving the stream data and the estimation packet sequence;
A stream distribution method characterized by estimating an available bandwidth of a network based on the received estimation packet sequence.
(Appendix 10)
Stream data receiving means for receiving stream data and an estimation packet sequence, and usable bandwidth estimation means for estimating an available bandwidth of the network based on the received estimation packet sequence. Stream packet transmission processing to be transmitted;
A stream distribution program causing a computer to execute a transmission method determination process for determining a transmission method for transmitting a part of the stream data as the estimation packet sequence.
(Appendix 11)
When the size of the stream data is less than a predetermined threshold, it is determined to transmit the stream data as the estimation packet sequence, and when the size of the stream data is equal to or larger than the threshold value, the stream data is converted to a normal packet sequence 7. The stream distribution device according to any one of appendices 1 to 6, further comprising: a transmission method determination unit that determines transmission as a transmission method.
(Appendix 12)
The stream delivery apparatus according to appendix 11, wherein the stream reception apparatus includes feedback transmission means for feeding back the estimation result of the available bandwidth to the stream delivery apparatus.
(Appendix 13)
13. The stream distribution apparatus according to appendix 12, wherein the stream distribution apparatus includes a parameter setting unit that changes the threshold based on the feedback estimation result.
(Appendix 14)
14. The stream delivery apparatus according to appendix 12 or appendix 13, wherein the stream delivery apparatus includes a bit rate control unit that controls a bit rate of the stream data based on the estimation result fed back.
(Appendix 15)
A stream packet transmitting means for transmitting stream data; and a transmission method determining means for determining a transmission method for transmitting a part of the stream data as an estimation packet sequence. A stream packet reception process for receiving a packet sequence;
A stream reception program that causes a computer to execute an available bandwidth estimation process for estimating an available bandwidth of a network based on the received packet sequence for estimation.
(Appendix 16)
The constraint condition is that the size of the stream data included in one of the estimation packet sequences is equal to or smaller than the size of the stream data, and the current stream data until the next stream data is input. Transmission is completed, the lower limit of the available bandwidth that can be estimated is less than or equal to a predetermined lower limit value, and the upper limit of the available bandwidth that can be estimated is greater than or equal to a predetermined upper limit value. The stream delivery device according to Supplementary Note 2 or Supplementary Note 3, wherein

  INDUSTRIAL APPLICABILITY The present invention can be used in a live video distribution system that distributes photographed video to a remote place, a video conference system or a telepresence system for communicating between remote places.

DESCRIPTION OF SYMBOLS 100 Stream delivery apparatus 200 Stream reception apparatus 300 Network 400 Stream delivery system 110 Parameter setting means 120 Stream data input means 130 Transmission method determination means 140 Packet specification determination means 150 Packet generation means 160 Stream packet transmission means 210 Stream packet reception means 220 Stream data Processing means 230 Available bandwidth estimation means 105 Stream distribution device 115 Parameter setting means 125 Stream data input means 170 Feedback reception means 180 Bit rate control means 190 Stream data generation means 205 Stream reception device 235 Available bandwidth estimation means 240 Feedback transmission means 405 Stream distribution system 106 Stream distribution device 20 Stream reception apparatus 136 transmission method determining unit 166 Stream packet transmitting means 216 stream packet receiving means 236 available bandwidth estimation section 406 stream distribution system

Claims (10)

Stream data receiving means for receiving stream data and an estimation packet sequence, and usable bandwidth estimation means for estimating an available bandwidth of the network based on the received estimation packet sequence. A stream packet transmitting means for transmitting;
A stream distribution apparatus comprising: a transmission method determination unit that determines a transmission method for transmitting a part of the stream data as the estimation packet sequence. The stream distribution apparatus according to claim 1, further comprising a packet specification determining unit that determines a size and a transmission time of each packet included in the estimation packet sequence so as to satisfy a given constraint condition. . The packet specification determining means maximizes the first objective function having a positive correlation with the accuracy of the estimation or satisfies the size and the transmission time while satisfying the constraint condition, or The stream distribution device according to claim 2, wherein the second objective function having the correlation of the second objective function is determined to be minimized. The packet specification deciding means, from the input parameter including the size of the stream data, from the estimation packet sequence, the size of the packet that appears first, the size increment between two adjacent packets, the number of packets, 4. The stream delivery apparatus according to claim 2, wherein an output parameter including a packet transmission period is determined. When the size of the stream data is less than a predetermined threshold, it is determined to transmit the stream data as the estimation packet sequence, and when the size of the stream data is equal to or larger than the threshold value, the stream data is converted to a normal packet sequence 5. The stream distribution device according to claim 1, further comprising: a transmission method determination unit that determines transmission as. 6. The stream receiving apparatus according to claim 5, further comprising: feedback transmission means for feeding back the estimation result of the available bandwidth; and parameter setting means for changing the threshold based on the fed back estimation result. 2. The stream delivery device according to 1. A stream packet transmitting means for transmitting stream data; and a transmission method determining means for determining a transmission method for transmitting a part of the stream data as an estimation packet sequence. Stream packet receiving means for receiving a packet sequence;
A stream receiving device comprising: an available bandwidth estimating unit that estimates an available bandwidth of a network based on the received estimation packet sequence. A stream receiving device including stream packet receiving means for receiving stream data and an estimation packet sequence; and an available bandwidth estimation means for estimating an available bandwidth of the network based on the received estimation packet sequence;
A stream distribution apparatus comprising: stream packet transmission means for transmitting the stream data; and a transmission method determination means for determining a transmission method for transmitting a part of the stream data as the estimation packet sequence. Stream delivery system. Determining a transmission method for transmitting a part of the stream data as an estimation packet sequence, transmitting the stream data,
Receiving the stream data and the estimation packet sequence;
A stream distribution method characterized by estimating an available bandwidth of a network based on the received estimation packet sequence. Stream data receiving means for receiving stream data and an estimation packet sequence, and usable bandwidth estimation means for estimating an available bandwidth of the network based on the received estimation packet sequence. Stream packet transmission processing to be transmitted;
A stream distribution program causing a computer to execute a transmission method determination process for determining a transmission method for transmitting a part of the stream data as the estimation packet sequence.

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