JP6724517B2 - Bit rate instruction device, bit rate instruction method, and bit rate instruction program - Google Patents

Description

The present invention relates to, for example, a bit rate indicating device capable of controlling communication related to a communication network.

In a best-effort communication network such as the Internet and a mobile network, the available communication network band (communication network bandwidth, hereinafter, available band) varies depending on the influence of congestion conditions, wireless communication quality, and the like. Regarding such a communication network, there is a technique of controlling a bit rate representing the amount of data per unit time when stream data is communicated, as the available bandwidth changes.

For example, the communication device disclosed in Patent Document 1 has an optimum bit rate based on an evaluation function including a delay related to a communication network and a bit rate indicating the amount of data per unit time communicated via the communication network. And an available bandwidth estimating unit that estimates an available bandwidth related to the communication network. The optimum bit rate calculation unit calculates, as an optimum bit rate, a bit rate that is less than or equal to the available band calculated by the available band estimation unit and has the maximum value of the evaluation function. The optimum bit rate calculation unit stochastically changes the value of the bit rate, determines whether or not the value of the evaluation function increases according to the changed bit rate, and based on the value of the evaluation function, Search for the bit rate with the highest value. The evaluation function is, for example, a function that represents the quality received by the user (user experience quality).

Non-Patent Document 1 discloses a method of estimating the user experience quality based on information such as a bit rate, a delay, and a packet loss rate observed when communicating video data.

JP, 2014-229956, A

ITU-T Recommendation G.M. 1070, _"Multimedia Quality of Service and performance-Generic and user-related aspects".

The method disclosed in Patent Document 1 has a problem that it may take a long time until the evaluation function (for example, the user experience quality) reaches the maximum value. As a result, according to the method disclosed in Patent Document 1, the value obtained by temporally averaging the user experience quality may be low. In other words, the method disclosed in Patent Document 1 has a problem that the user experience quality for a stream may be poor.

Therefore, a main object of the present invention is to provide a bit rate indicating device or the like that can improve the quality of information communication via a communication network in a short time.

In order to achieve the above object, in one aspect of the present invention, a bit rate indicating device is
The bit rate model in the bit rate information including a plurality of bit rate models representing the extent to which the amount of data per unit time relating to the data communicated via the communication network changes over time, and the communication of the communication network Creates a delay model that represents the degree to which the delay time of communication performed via the communication network changes with time, based on the difference from the available bandwidth model that represents the degree to which the band changes with time. Delay model creating means to
Quality model creating means for creating a quality model representing the degree of the communication quality changing over time based on the delay model and the bit rate model,
Based on the quality represented by the created quality model, among the plurality of bit rate models included in the bit rate information, the quality in a certain period follows a bit rate model larger than other bit rate models. A bit rate instruction means for instructing a control device controlling the communication network so as to control the amount of data per unit time.

Further, as another aspect of the present invention, a bit rate indicating method is
The bit rate model in the bit rate information including a plurality of bit rate models representing the extent to which the amount of data per unit time relating to the data communicated via the communication network changes over time, and the communication of the communication network Creates a delay model that represents the degree to which the delay time of communication performed via the communication network changes with time, based on the difference from the available bandwidth model that represents the degree to which the band changes with time. Then
The quality of the communication, the quality model representing the degree of transition over time, based on the delay model and the bit rate model,
Based on the quality represented by the created quality model, among the plurality of bit rate models included in the bit rate information, the quality in a certain period follows a bit rate model larger than other bit rate models. , Instructing the control device controlling the communication network to control the amount of data per unit time.

Further, as another aspect of the present invention, the bit rate instruction program is
The bit rate model in the bit rate information including a plurality of bit rate models representing the extent to which the amount of data per unit time relating to the data communicated via the communication network changes over time, and the communication of the communication network Create a delay model that represents the degree to which the delay time of communication performed via the communication network changes with time, based on the difference from the available bandwidth model that represents the degree to which the band changes with time. Delay model creation function to
A quality model creating function for creating a quality model representing the degree of the communication quality changing with time, based on the delay model and the bit rate model,
Based on the quality represented by the created quality model, among the plurality of bit rate models included in the bit rate information, the quality in a certain period follows a bit rate model larger than other bit rate models. And a bit rate instruction function for instructing a control device controlling the communication network so as to control the amount of data per unit time.

Further, the same object is also realized by a computer-readable recording medium that records the program.

According to the bit rate instruction device and the like according to the present invention, it is possible to improve the communication quality of information in a short time.

It is a block diagram which shows the structure which the stream delivery system which concerns on the 1st Embodiment of this invention has. It is a block diagram which shows the structure which the stream delivery apparatus which concerns on the 1st Embodiment of this invention has. 5 is a flowchart showing a flow of processing in the stream distribution device according to the first embodiment. 3 is a flowchart showing a flow of processing in which the stream distribution device according to the first embodiment instructs a bit rate according to a bit rate model. It is a figure which represents notionally an example of the bit rate model in the bit rate information stored in the bit rate information storage part. It is a figure which represents notionally an example of a delay model. FIG. 7 is a diagram conceptually illustrating an example of a user experience quality model calculated based on the bit rate model illustrated in FIG. 5 and the delay model illustrated in FIG. 6. It is a figure which represents notionally an example of a bit rate model. It is a block diagram which shows the structure which the stream delivery system which concerns on the 2nd Embodiment of this invention has. It is a figure which represents notionally an example of the structure which the transmission part in the stream delivery apparatus which concerns on 2nd Embodiment has. It is a flowchart which shows the flow of a process in the stream delivery apparatus which concerns on 2nd Embodiment. It is a block diagram which shows the structure which the stream delivery apparatus which concerns on the 3rd Embodiment of this invention has. It is a figure which represents notionally an example of a bit rate model. It is a block diagram which shows the structure which the stream delivery apparatus which concerns on the 4th Embodiment of this invention has. It is a figure which represents notionally an example of a bit rate model. It is a block diagram which shows the structure which the stream delivery apparatus which concerns on the 5th Embodiment of this invention has. It is a figure which represents notionally an example of a bit rate model. It is a figure which represents notionally an example of a bit rate model. It is a figure which represents notionally an example of a bit rate model. It is a block diagram which shows the structure which the stream delivery apparatus which concerns on the 6th Embodiment of this invention has. It is a figure which represents notionally an example of a bit rate model. It is a block diagram which shows the structure which the bit rate instruction|indication apparatus which concerns on the 7th Embodiment of this invention has. FIG. 1 is a block diagram schematically showing a hardware configuration example of a stream distribution device or a calculation processing device capable of realizing a bit rate instruction device according to each embodiment of the present invention. It is a figure showing the bit rate about the communication system, the degree of this delay, the bit rate, and the user experience quality showing the quality about the communication network when the delay is observed. It is a figure showing the bit rate about the communication system, the degree of this delay, the bit rate, and the user experience quality showing the quality about the communication network when the delay is observed. It is a figure showing the bit rate about the communication system, the degree of this delay, the bit rate, and the user experience quality showing the quality about the communication network when the delay is observed. It is a figure showing the bit rate about the communication system, the degree of this delay, the bit rate, and the user experience quality showing the quality about the communication network when the delay is observed.

To facilitate understanding of the present invention, the problem to be solved by the present invention will be described in detail with reference to FIG. FIG. 24 shows a bit rate, a degree of delay (for example, a delay time), a bit rate, and a communication performed via a communication network when the delay is observed, regarding the communication system. It is a figure showing the user experience quality showing quality. The horizontal axis represents the timing, and the right side indicates that the time advances. In (a) of FIG. 24, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate. In FIG. 24B, the vertical axis represents the degree of delay, and the higher the level, the greater the degree of delay. In (c) of FIG. 24, the vertical axis represents the user experience quality, and the higher the axis, the better the user experience quality.

In FIG. 24, L1 represents the transition of the available bandwidth. L2 represents the transition of the bit rate. L3 represents the degree of delay (for example, delay time). L4 represents the user experience quality.

For convenience of explanation, regarding the communication system, it is assumed that the available bandwidth L1 increases at the timing t1. In the communication system, it is assumed that the increase of the available bandwidth at the timing t1 is detected at the timing t2.

The communication device disclosed in Patent Document 1, for example, stochastically selects from among a process of increasing the bit rate, a process of not changing the bit rate, or a process of decreasing the bit rate when the available bandwidth is changed, Select the process to be executed next. When the “increasing process” is selected at the timing t2, the communication device executes the process of increasing the bit rate according to the selected process. Referring to FIG. 24A, the bit rate L2 increases during the period from the timing t2 to the timing t3. This means that the bit rate L2 increases, for example, when the communication device continuously selects the "increasing process" in the period from the timing t2 to the timing t3.

In addition, when the bit rate L2 exceeds the available bandwidth L1, the communication device disclosed in Patent Document 1 stochastically executes the next process from “unchanged process” or “reduced process”. Select the process to be performed. For example, referring to FIG. 24A, the bit rate L2 is a constant value in the period after the timing t3. This means that the bit rate L2 is constant, for example, when the communication device continuously selects the “non-change processing” in the period after the timing t3. However, since the communication device disclosed in Patent Document 1 stochastically selects the process to be executed next, the bit rate L2 is not always constant.

When the delay L3 is constant as shown in (b) of FIG. 24 and the bit rate L2 is increased in the period from the timing t2 to the timing t3 as shown in (a) of FIG. In addition, the user experience quality L4 increases during the period ((c) of FIG. 24). In this case, the communication device disclosed in Patent Document 1 determines that the process of increasing the bit rate L2 has succeeded.

However, the communication device disclosed in Patent Document 1 does not always calculate the optimum bit rate with respect to the user experience quality. The reason for this will be described with reference to FIG. FIG. 25 is a diagram showing the bit rate, the degree of delay, the bit rate, and the user experience quality indicating the quality of the communication network when the delay is observed in the communication system. In FIG. 25, (a), (b), (c), the vertical axis, and the horizontal axis are the same as in FIG.

In FIG. 25, L1 represents the transition of the available bandwidth. L5 represents the transition of the bit rate. L3 represents the degree of delay (for example, delay time). L6 represents the user experience quality.

For convenience of explanation, regarding the communication system, it is assumed that the available bandwidth L1 increases at the timing t1. In the communication system, it is assumed that the increase of the available bandwidth L1 at the timing t1 is detected at the timing t2. Further, in the communication system, the bit rate L5 is assumed to increase to the available bandwidth L1 at the timing t2. In such a case, the bit rate L5 is the optimum control method.

As the bit rate L5 increases to the available band L1 at the timing t2, the user experience quality L6 increases at the timing t2. Comparing the user experience quality L4 shown in (c) of FIG. 24 and the user experience quality L6 shown in (c) of FIG. 25, the user experience quality L4 is as follows in the period from the timing t2 to the timing t3. It is lower than the user experience quality L6. In other words, the average value of the user experience quality in a certain period (for example, the period from the timing t2 to the timing t3) is lower in the user experience quality L4 than in the user experience quality L6. Therefore, the method of controlling the bit rate as illustrated in FIG. 25 is a control method with higher user experience quality than the method disclosed in Patent Document 1.

It will be described that there is a control method having a higher user experience quality than the method disclosed in Patent Document 1 even when the available bandwidth is reduced as illustrated in FIG. FIG. 26 is a diagram showing the bit rate, the degree of delay, the bit rate, and the user experience quality indicating the quality of the communication network when the delay is observed in the communication system. 26, (a), (b), (c), the vertical axis, and the horizontal axis are the same as those in FIG.

In FIG. 26, L1 represents the transition of the available bandwidth. L2 represents the transition of the bit rate. L3 represents the degree of delay (for example, delay time). L4 represents the user experience quality.

For convenience of explanation, regarding the communication system, it is assumed that the available bandwidth L1 decreases at the timing t1. In the communication system, it is assumed that the reduction of the available band L1 at the timing t1 is detected at the timing t2.

Referring to (a) of FIG. 26, the bit rate L2 is higher than the available band L1 in the period from the timing t1 to the timing t2. Therefore, the data that could not be transmitted during the period is temporarily stored in the buffer in the communication system. Since the data stored in the buffer is communicated as it becomes possible to communicate via the communication network, the delay L3 increases in the period from the timing t1 to the timing t2. As a result, the user experience quality L4 decreases in the period from the timing t1 to the timing t2.

For convenience of explanation, the communication device "decreases" the bit rate L2 until it becomes less than the available bandwidth L1 at the timing t2, for example, by detecting that the available bandwidth L1 has dropped at the timing t1 at the timing t2. Suppose you choose. In this case, since the bit rate L2 is less than the available band L1 in the period from the timing t2 to the timing t3, the delay L3 decreases. As a result, the user experience quality L4 increases during the period from the timing t2 to the timing t3.

For convenience of explanation, the communication device continuously selects the “reduction process” of the bit rate L2 until the process on the data stored in the buffer is completed (the period is from the timing t3 to the timing t4). And In this case, since the bit rate L2 is less than the available band L1 in the period from the timing t3 to the timing t4, the delay L3 decreases. As a result, the user experience quality L4 increases during the period from the timing t3 to the timing t4.

As illustrated in (a) of FIG. 26, it is assumed that the communication device continuously selects the “increasing process” of the bit rate L2 in the period from the timing t4 to the timing t5. In this case, in the period from the timing t4 to the timing t5, the bit rate L2 increases without increasing the delay L3, and the user experience quality L4 increases.

However, the communication device that controls the bit rate as illustrated in FIG. 26 does not always calculate the optimum bit rate with respect to the user experience quality. The reason for this will be described with reference to FIG. FIG. 27 is a diagram showing the bit rate, the degree of delay, the bit rate, and the user experience quality indicating the quality of the communication network when the delay is observed in the communication system. 27, (a), (b), (c), the vertical axis, and the horizontal axis are the same as those in FIG.

In FIG. 27, L1 represents the transition of the available bandwidth. L5 represents the transition of the bit rate. L3 represents the degree of delay (for example, delay time). L6 represents the user experience quality.

Regarding the bit rate, comparing the bit rate L2 shown in (a) of FIG. 26 and the bit rate L5 shown in (a) of FIG. 27, the communication device determines the bit rate L5 at timing t2. , The bit rate L2 is reduced to a value smaller than the bit rate L2. As a result, comparing the timings at which the delays are eliminated, the delay L3 shown in (b) of FIG. 26 is the timing t4, while the delay L3 shown in (b) of FIG. The timing t3 is earlier than the timing t4.

Further, assuming that the communication device increases the bit rate L5 to the available bandwidth L1 at the timing t3 when the delay is eliminated, the user experience quality L6 improves at the timing t3. As a result, when the user experience quality L6 (illustrated in FIG. 27) and the user experience quality L4 (illustrated in FIG. 26) are compared, the user experience quality L4 is the user experience quality L6 in the period from the timing t2 to the timing t5. Lower than. In other words, the average value of the user experience quality in a certain period (for example, the period from the timing t2 to the timing t5) is lower in the user experience quality L4 than in the user experience quality L6. Therefore, the method of controlling the bit rate as illustrated in FIG. 27 is a control method with higher user experience quality than the method of controlling the bit rate as illustrated in FIG.

The inventor of the present application has found out the problems as described with reference to FIGS. 24 to 27, and has derived means for solving the problems. Hereinafter, embodiments for carrying out the present invention capable of solving such problems will be described in detail with reference to the drawings.

<First Embodiment>
The configuration of the stream distribution system 4 according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a block diagram showing a configuration of a stream distribution system 4 according to the first embodiment of the present invention.

The stream distribution system 4 according to the first embodiment of the present invention includes a stream distribution device 1 that distributes stream data, a stream reception device 2 that receives stream data, and a communication network 3.

The stream distribution device 1 and the stream reception device 2 can be communicatively connected via a communication network 3. The communication network 3 is, for example, the Internet, a mobile communication network, an in-house communication network (intranet), a home LAN (Local_Area_Network), or a communication network in which these communication networks are combined.

In the stream distribution system 4, a plurality of stream receiving apparatuses 2 may be communicatively connected to one stream distributing apparatus 1. The stream distribution system 4 may also have a bidirectional structure in which stream data is distributed from the stream receiving apparatus 2 to the stream distributing apparatus 1.

The configuration of the stream distribution device 1 according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 2 is a block diagram showing a configuration of the stream distribution device 1 according to the first embodiment of the present invention.

The stream distribution device 1 according to the first embodiment of the present invention includes a stream data input unit 11, an encoding unit 12, a transmission unit 13, an available bandwidth unit 14, a buffer amount estimation unit 15, and a delay model creation. It has a unit 16, a quality model creation unit 17, a bit rate model selection unit 18, a transmission delay estimation unit 19, and a bit rate information storage unit 20.

The stream data input unit 11 inputs stream data to be transmitted from an external device (not shown). Stream data is, for example, information such as video data, audio data, operation information, and sensor information. The external device (not shown) is, for example, an image pickup device such as a camera, a microphone, a controller, or a sensor (none of which is shown). The stream data input unit 11 outputs the input stream data to the encoding unit 12.

The encoding unit 12 inputs the stream data output by the stream data input unit 11 and executes an encoding process of encoding the input stream data based on an instruction (described later) from the bit rate model selection unit 18. .. For example, when the video data is input, the encoding unit 12 determines the H.264 standard. H.264 or H.264. The encoding process may be executed according to a codec such as H.265 (HEVC). The encoding unit 12, for example, when the audio data is input, the G.I. The encoding process may be executed according to a codec such as 711, AMR, and AAC. The encoding unit 12 outputs the stream data created by encoding the stream data (hereinafter referred to as “encoded stream data”) to the transmission unit 13.

HEVC stands for High_Efficiency_Video_Coding. AAC is an abbreviation for Advanced_Audio_Coding. AMR represents an abbreviation of Adaptive_Multi-Rate.

The transmission unit 13 inputs the encoded stream data output from the encoding unit 12, creates a packet related to the input encoded stream data, and transmits the created packet to the stream receiving apparatus 2. The transmission unit 13 may create data to which a header such as RTP (Real-time_Transport_Protocol) is added to the encoded stream data to be transmitted, and may transmit a packet related to the created data.

Next, a control process regarding the bit rate will be described.

The available band unit 14 estimates (or predicts) an available communication band (available band) with respect to the communication network 3 between the stream distribution device 1 and the stream receiving device 2. When the available band can be acquired from the communication device or the like that constitutes the communication network 3, it may be acquired without estimation. The available band unit 14 outputs the estimated (or predicted) available band to the delay model creation unit 16.

The buffer amount estimation unit 15 acquires (or the amount of data stored in the buffer of the stream distribution device 1 and each device communicatively connected to the communication network 3 (hereinafter, referred to as “transmission buffer amount”)). , Estimate, and measure). The buffer amount estimation unit 15 outputs the acquired (or estimated, measured) data amount to the delay model creation unit 16.

The transmission delay estimation unit 19 acquires (or estimates) the transmission delay when data is transmitted from the stream distribution device 1 to the stream reception device 2. Here, the transmission delay represents, for example, a time required to transmit a packet from the stream distribution device 1 to the stream reception device 2. The required time does not include the period stored in the buffer.

The bit rate model selection unit 18 selects a certain bit rate model from the bit rate information storage unit 20 that stores the bit rate information including a plurality of bit rate models according to the case of controlling the bit rate, and selects the selected certain bit rate. The model is output to the delay model creating unit 16 and the quality model creating unit 17. As will be described later with reference to FIG. 5 and the like, in the bit rate model, the amount of data communicated via the communication network 3 per unit time changes with the passage of time (related ) Indicates the degree.

The delay model creating unit 16 outputs the available bandwidth output from the available bandwidth unit 14, the data amount output from the buffer amount estimating unit 15 (that is, the data amount stored in the buffer), and the bit rate model selecting unit 18 outputs. The input bit rate model and the transmission delay output by the transmission delay estimation unit 19 are input. The delay model creation unit 16 calculates the delay model based on the input value and according to the procedure described later with reference to Expressions 1 to 5 and the like. The delay model represents the degree to which the delay time of communication via the communication network 3 changes (is related) with the passage of time.

The quality model creation unit 17 inputs the bit rate model output by the bit rate model selection unit 18 and the delay model related to the bit rate model, and based on the input bit rate model and the delay model, see Formula 6. However, the quality model is calculated according to the procedure described below.

The bit rate model selection unit 18 calculates the quality in a certain period based on the quality model calculated by the quality model creation unit 17 according to the procedure described later with reference to FIG.

The bit rate model selection unit 18, the delay model creation unit 16, and the quality model creation unit 17 execute the above-described processing for each bit rate model stored in the bit rate information storage unit 20. After that, the bit rate model selection unit 18 selects and selects, for example, the bit rate model whose calculated quality is maximum (or approximately maximum) from the bit rate models stored in the bit rate information storage unit 20. The encoding unit 12 is requested to perform encoding according to the bit rate model.

Next, the processing in the stream distribution device 1 according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 3 is a flowchart showing the flow of processing in the stream distribution device 1 according to the first embodiment.

The stream data input unit 11 receives stream data from, for example, an external device (not shown) or the like (step S1101). When the stream data is video data, the stream data input unit 11 receives the stream data, for example, for each frame included in the video data. When the stream data is audio information, operation information, sensor information, or the like, the stream data input unit 11 may receive the stream data at a constant cycle such as 20 milliseconds. The stream data input unit 11 outputs the input stream data to the encoding unit 12.

Next, the encoding unit 12 inputs the stream data output by the stream data input unit 11 and executes an encoding process of encoding the input stream data according to the bit rate model output by the bit rate model selection unit 18. Yes (step S1102). The encoding unit 12 outputs the encoded stream data representing the result of encoding the stream data to the transmission unit 13.

The transmission unit 13 receives the encoded stream data output from the encoding unit 12, creates a packet including the input encoded stream data, and transmits the created packet to the stream receiving apparatus 2 (step S1103). ..

The stream distribution device 1 determines whether the process of distributing the stream data has been completed (step S1104). When the process of distributing the stream data is not completed (NO in step S1104), the process shown in step S1101 is executed. When the process of distributing the stream data is completed (YES in step S1104), the stream distribution device 1 ends the process. That is, the stream distribution device 1 repeatedly executes the processing shown in steps S1101 to S1104 until the distribution processing is completed.

Next, with reference to FIG. 4, a process in which the stream distribution device 1 according to the first embodiment of the present invention instructs a bit rate according to a bit rate model will be described in detail. FIG. 4 is a flowchart showing a flow of processing in which the stream distribution device 1 according to the first embodiment instructs a bit rate according to a bit rate model. The stream distribution device 1 may execute the process of determining the bit rate model at a predetermined timing (for example, a constant cycle, a one-second cycle), or the amount of communication in the communication network 3 changes abruptly. The process of determining the bit rate model may be executed in response to the event of.

The available band unit 14 estimates (or predicts) the available band regarding the communication network 3 between the stream distribution device 1 and the stream receiving device 2 (step S1201).

When estimating the available band, the available band unit 14 transmits a plurality of packets to the stream receiving apparatus 2 at a certain timing, for example. The available bandwidth unit 14 determines the sizes of the plurality of packets based on the sizes of the plurality of packets and the time required from the transmission of the plurality of packets to the end of reception of the number of packets by the stream receiving apparatus 2. The available bandwidth at the certain timing may be estimated by dividing by the required time.

Alternatively, the available band unit 14 receives a plurality of packets transmitted at a certain timing of the stream receiving device 2 when estimating the available band. The available bandwidth unit 14 determines the size of the received packet based on the size of the received packet and the time required from the transmission of the plurality of packets by the stream receiving apparatus 2 to the end of receiving the number of packets. The available bandwidth at a certain timing may be estimated by dividing by the required time.

The available band unit 14 may estimate the available band estimated according to the above-described processing as the available band in a certain period after the certain timing. Alternatively, the available band unit 14 processes the history of the available band estimated (or measured) at a certain timing according to the estimation procedure as exemplified in International Publication 2014/007166, thereby The available band may be estimated. That is, the method of estimating the available band is not limited to the above example.

The buffer amount estimation unit 15 acquires (or estimates) the amount of data stored in the buffers of the stream distribution device 1 and a device (which will be described later with reference to FIG. 9) communicatively connected to the communication network 3. Yes (step S1202). For example, in the stream distribution device 1, when the operating system or the like provides an API capable of acquiring the buffer amount, the data amount may be acquired via the API. Alternatively, the delay time (RTT, Round_Trip_Time) when a packet makes a round trip from the stream distribution device 1 to the stream reception device 2 may be measured and estimated from the difference between the current value and the minimum value of the RTT. Note that API represents an abbreviation of Application_Programming_Interface.

The transmission delay estimation unit 19 acquires (or estimates) a transmission delay time that represents the time required to transmit data from the stream distribution device 1 to the stream reception device 2 (step S1203). However, it is assumed that the transmission delay time is a required time that does not include the processing time through the buffer. The transmission delay estimator 19 transmits a probe packet such as ICMP_Echo from the stream distribution device 1 to the stream reception device 2 as an estimated value related to the transmission delay time, until the confirmation response corresponding to the probe packet is received. One half of the round-trip delay time required for the calculation may be calculated. In addition, the transmission unit 13 transmits a packet, and the half (1/2) of the minimum time required for receiving the confirmation response transmitted by the stream receiving apparatus 2 in response to the transmitted packet is The transmission delay estimation unit 19 may estimate the transmission delay time.

Note that ICMP represents the abbreviation of Internet_Control_Message_Protocol.

Next, the transmission delay estimation unit 19, the quality model creation unit 17, and the bit rate model selection unit 18 will be described later with reference to Expression 6 regarding the bit rate model stored in the bit rate information storage unit 20. According to the above, the quality model is calculated (step S1204 and step S1205). The processing shown in steps S1204 and S1205 is executed for each bit rate model stored in the bit rate information storage unit 20.

A procedure for calculating the quality model based on the bit rate model in steps S1204 and S1205 will be described with reference to FIG. FIG. 5 is a diagram conceptually showing an example of a bit rate model in the bit rate information stored in the bit rate information storage unit 20. In FIG. 5, the horizontal axis represents the timing, and the right side indicates that the time advances. In FIG. 5, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate.

For convenience of description, the reference timing is t0 [seconds (s)], the transmission delay time relating to the communication network at the timing t (where t≧t0) is dT(t), and the value indicating the available band at the timing t (or The estimated value) is represented as C(t) [bits per second (bps)]. Further, the buffer amount at the timing t is represented as B(t) [bit (bit)], and the bit rate model at the timing t is represented as r(t).

The bit rate information storage unit 20 stores, for example, a bit rate model r1(t), a bit rate model r2(t), a bit rate model r3(t), and a bit rate model r4 as illustrated in FIG. Bit rate information including (t) is stored. The bit rate model stored in the bit rate information storage unit 20 does not necessarily have to be the bit rate model illustrated in FIG. Further, the bit rate information storage unit 20 may further store many bit rate models. That is, the bit rate model stored in the bit rate information storage unit 20 is not limited to the bit rate model illustrated in FIG.

The delay model creation unit 16 uses the delay model d for the bit rate model r(t) (for example, the bit rate model ri(t) illustrated in FIG. 5, where i=1, 2, 3, or 4). (T) is calculated (step S1204). For example, the delay model creation unit 16 follows the processing shown in Expression 1 with the transmission delay time dT(t) regarding the communication network and the required time dB(t) required for the processing regarding the buffer (that is, buffering) in the communication network. The delay model d(t) is calculated by adding That is,
Delay model d(t)=dT(t)+dB(t)... (Formula 1).

Next, a process in which the delay model creating unit 16 calculates the required time dB(t) required for buffering will be described.

ただし、バッファ量Ｂ（ｔ）は、０以上である。 The delay model creation unit 16 uses the input speed representing the speed at which the data is stored in the buffer, and the output speed representing the speed at which the data stored in the buffer is erased from the input speed, in accordance with Equation 2. Is calculated to calculate the speed at which the data stored in the buffer increases or decreases. That is,

However, the buffer amount B(t) is 0 or more.

。 The delay model creating unit 16 calculates the buffer amount B(t) at the timing t by solving the differential equation shown in Expression 2. Next, the delay model creation unit 16 calculates the time required for completing the processing regarding the buffer amount B(t) stored in the buffer at the timing t as the time required for buffering dB(t). To do. When the timing at which the process related to the buffer amount B(t) stored in the buffer is completed is represented by tx, the delay model creating unit 16 calculates the timing tx according to Expression 3. That is,

..

The delay model creation unit 16 calculates the required time dB(t) required for buffering by subtracting the timing t from the timing tx. That is, the delay model creating unit 16 calculates the required time dB(t) according to the equation 4.
dB(t)=tx−t (Equation 4).

The delay model creating unit 16 calculates the required time dB(t) required for buffering by dividing the buffer amount B(t) at the timing t by the available bandwidth C(t) at the timing t according to Equation 5. You may. That is,
dB(t)=B(t)÷C(t) (Equation 5).

The delay model creation unit 16 calculates the delay model shown in FIG. 6 for each bit rate model (illustrated in FIG. 5) stored in the bit rate information storage unit 20. FIG. 6 is a diagram conceptually showing an example of the delay model. In FIG. 6, the horizontal axis represents timing, and the right side indicates that the time advances. In FIG. 6, the vertical axis represents the delay, and the higher the axis, the more the delay increases. For convenience of description, in FIG. 6, the required time dB(t) calculated for the bit rate model r1(t) is represented by the reference sign “r1(t)”. Similarly, the required time dB(t) calculated for the bit rate model r2(t) is represented by the reference sign "r2(t)". The required time dB(t) calculated for the bit rate model r3(t) is represented by adding the symbol "r3(t)". The required time dB(t) calculated for the bit rate model r4(t) is represented by adding the symbol “r4(t)”.

The quality model creating unit 17 stores the bit rate model r(t) stored in the bit rate information storage unit 20 and the delay model d(calculated according to Formulas 1 to 5 based on the bit rate model r(t). t) and enter. The quality model creating unit 17 calculates a quality model q(t) for the input bit rate model r(t) and the delay model d(t), for example, according to the method disclosed in Patent Document 1. For example, as disclosed in Patent Document 1, the quality model q(t) is a function including at least a bit rate and a delay time as parameters. The quality model creation unit 17 may, for example, use ITU-T_G. The quality model q(t) may be calculated according to the procedure defined in 1070. When the quality model q(t) includes a parameter other than the bit rate and the delay (for example, packet loss rate), the quality model creating unit 17 uses a predetermined value as the value of the parameter. Good. In other words, the quality model creation unit 17 uses the method disclosed in Patent Document 1 or ITU-T_G. The quality model q(t) is calculated by executing the process shown in Expression 6 at the timing t according to the procedure disclosed in the literature such as 1070. That is,
q(t)=f(r(t), d(t),...) (Equation 6).

However, ITU represents the abbreviation of International Telecommunication Union (International_Telecommunication_Union).

The quality model creation unit 17 calculates a user experience quality model as illustrated in FIG. 7 according to Equation 6. FIG. 7 is a diagram conceptually illustrating an example of the user experience quality model calculated based on the bit rate model illustrated in FIG. 5 and the delay model illustrated in FIG. 6. In FIG. 7, the horizontal axis represents timing, and the right side indicates that time advances. In FIG. 7, the vertical axis represents the quality, and the higher the axis, the better (increase) the quality. For convenience of explanation, in FIG. 7, the user experience quality model calculated with respect to the bit rate model r1(t) is denoted by reference numeral “r1(t)”. Similarly, the user experience quality model calculated for the bit rate model r2(t) is represented by the reference symbol "r2(t)". The user experience quality model calculated for the bit rate model r3(t) is represented by the reference sign "r3(t)". The user experience quality model calculated for the bit rate model r4(t) is represented by the reference sign "r4(t)".

Note that the processing shown in step S1204 and step S1205 in FIG. 4 does not necessarily have to be executed for continuous time, and may be executed for discretely given timing t. In this case, the delay model illustrated in FIG. 6 and the quality model illustrated in FIG. 7 are calculated only with respect to the discretely given timing t. However, for convenience of explanation, in FIGS. 5 to 7, the delay model, the bit rate model, and the quality model are represented as continuous functions.

The processing shown in steps S1204 and S1205 in FIG. 4 is executed for each bit rate model stored in the bit rate information storage unit 20. After that, the bit rate model selection unit 18 selects a certain bit rate model from the bit rate models included in the bit rate information stored in the bit rate information storage unit 20 based on the calculated quality model. (Step S1206). The bit rate model selection unit 18 determines, for example, that the average value of the function is maximum (or approximately maximum) for the calculated user experience quality model from the bit rate models stored in the bit rate information storage unit 20. Select the bitrate model for your case. In this case, the bit rate model selection unit 18 calculates an integral value obtained by integrating the quality model q(t) in the period from the timing t0 to (t0+(constant time T) [s]), and calculates the calculated integral value. May be the maximum (or approximately maximum) bit rate model. The bit rate model selection unit 18 calculates the integral value regarding the quality model q(t), for example, according to the procedure of calculating the numerical integration.

In the example illustrated in FIG. 7, the bit rate model selection unit 18 determines, for example, that the integral value regarding the quality model q(t) in the section [t0, t0+T] (that is, the section from t0 to “t0+T”) is the maximum ( Alternatively, the bit rate model r4(t) which is approximately the maximum) is selected.

The bit rate model selection unit 18 instructs the coding unit 12 to request information for controlling the bit rate according to the selected bit rate model (step S1207). The bit rate model selection unit 18 may output the selected bit rate model to the encoding unit 12, or may output a parameter relating to the bit rate model or a numerical value indicating the bit rate. For example, when the selected bit rate model r(t) is “−0.1×t+1.0 [speed megabits per second, Mbps]”, the bit rate model selection unit 18 selects the timing from 0 to 1. To calculate an integrated value (a shaded portion in FIG. 8 (0.95 Mbps in this example)) relating to the bit rate model r(t), and output the calculated integrated value to the encoding unit 12. You may. FIG. 8 is a diagram conceptually showing an example of the bit rate model. In FIG. 8, the horizontal axis represents timing, and the right side indicates that time advances. In FIG. 8, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate.

The encoding unit 12 inputs the bit rate model (or the integral value or the value of the parameter) calculated by the bit rate model selecting unit 18. The encoding unit 12 selects a codec type for encoding the stream data according to the input stream data. When the bit rate that can be set for the codec type is determined in advance, the encoding unit 12 selects the input bit rate model (or the integral value, the value of the parameter, among the bit rates that can be set for the selected codec type). ), the bit rate may be selected. For example, of the voice codecs, G. For 711, the bit rate is set to 64 kbps (kilobits per second), and G.711. For 726, the bit rate is set to 16, 24, 32, or 48 kbps. For 729, the bit rate is set to 8 kbps. In this case, the encoding unit 12 may select, for example, the codec type relating to the bit rate closest to the input integrated value.

Next, effects of the stream distribution system 4 according to the first embodiment of the present invention will be described.

According to the stream distribution system 4 according to the first embodiment, it is possible to improve the communication quality of information (data) in a short time via the communication network. The reason for this is that it is possible to calculate the bit rate over a longer period than the communication device disclosed in Patent Document 1 and control communication according to the calculated bit rate. Therefore, the number of times communication is controlled is reduced as compared with the communication device disclosed in Patent Document 1, and thus the stream distribution system 4 according to the present embodiment can improve the quality of information communication in a short time. ..

Further, by selecting the bit rate model with the maximum (or approximately maximum) user experience quality model, it is possible to realize communication with even better quality. This is because the stream distribution system 4 selects the bit rate model having the maximum (or approximately maximum) quality model from the bit rate models included in the bit rate information.

<Second Embodiment>
Next, a second embodiment of the present invention based on the above-described first embodiment will be described.

In the following description, the characteristic part according to the present embodiment will be mainly described, and the same configurations as those in the above-described first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. To do.

The configuration of the stream distribution system 6 according to the second embodiment of the present invention will be described in detail with reference to FIG. FIG. 9 is a block diagram showing the configuration of the stream distribution system 6 according to the second embodiment of the present invention.

A stream distribution system 6 according to the second embodiment of the present invention includes a stream distribution device 1 that distributes stream data, a stream reception device 2 that receives stream data, and a communication network 5.

The stream distribution device 1 and the stream reception device 2 can be communicatively connected via a communication network 5. In the stream distribution system 6, a plurality of stream receiving apparatuses 2 may be communicatively connected to one stream distributing apparatus 1. Further, the stream distribution system 6 may have a bidirectional structure in which the stream data is distributed from the stream receiving apparatus 2 to the stream distributing apparatus 1.

The communication network 5 according to the second embodiment includes a base station device 51, a mobile core network 52, and the Internet 53. The stream distribution device 1 is, for example, a device including a smartphone (or a personal computer) and a communication device that is communicatively connected via an interface such as a USB. In the stream distribution system 6, the communication network 5 capable of communicatively connecting the stream distribution device 1 and the base station device 51 is, for example, a wireless communication network (hereinafter, referred to as a “wireless communication network”). The base station device 51 manages the wireless resources forming the wireless communication network. USB is an abbreviation for Universal_Serial_Bus.

The stream distribution device 1 will be described. The stream distribution device 1 according to the second embodiment includes the same configuration as the stream distribution device 1 according to the first embodiment shown in FIG.

The stream data input unit 11 is, for example, an input device such as an imaging device such as a camera, a microphone, a sensor, or the like that is built in (or connected to) a smartphone or the like. The transmitter 13 is, for example, a smartphone or a communication modem built in a communication device. Further, the encoding unit 12, the available band unit 14, the buffer amount estimating unit 15, the delay model creating unit 16, the quality model creating unit 17, the bit rate model selecting unit 18, and the transmission delay estimating unit 19 are, for example, smartphones or the like. Is a function realized by a program executed by a processor included in. The transmission unit 13 has a transmission buffer 131 as illustrated in FIG. FIG. 10 is a diagram conceptually illustrating an example of the configuration of the transmission unit 13 in the stream distribution device 1 according to the second embodiment.

The transmission buffer 131 has a queue structure in which input data is processed on a first-in first-out basis. For example, the transmission unit 13 inputs the encoded stream data output from the encoding unit 12, creates a packet including the input encoded stream data, and temporarily stores the created packet in the transmission buffer 131. Store. The transmission unit 13 reads the packet stored first among the packets stored in the transmission buffer 131 in response to the wireless resource being allocated by the base station device 51 (FIG. 9), and the read packet Is transmitted via the communication network 5. In this case, the transmission unit 13 deletes the transmitted packet from the transmission buffer 131.

Therefore, when the amount of encoded stream data input from the encoding unit 12 is larger than the amount of data that can be transmitted using the radio resource allocated by the base station device 51, the amount of data stored in the transmission buffer 131. Will increase. When the amount of encoded stream data input from the encoding unit 12 is less than the amount of data that can be transmitted using the wireless resource assigned by the base station device 51, the amount of data stored in the transmission buffer 131 decreases. To do.

Next, the processing in the stream distribution device 1 according to the second embodiment of the present invention will be described in detail with reference to FIG. FIG. 11 is a flowchart showing the flow of processing in the stream distribution device 1 according to the second embodiment.

The available bandwidth unit 14 acquires the amount of data transmitted by the transmission unit 13 per unit time (step S1301). In this case, the available bandwidth unit 14 may measure the amount of data transmitted from the transmitter 13 or may input the amount of data from the transmitter 13. The available band unit 14 may set the input data amount as an estimated value regarding the available band. Further, the buffer amount estimation unit 15 may acquire the data amount stored in the transmission buffer 131 from the transmission unit 13 (step S1302), and use the acquired value as the estimated buffer amount value.

Next, effects of the stream distribution system 6 according to the second embodiment of the present invention will be described.

According to the stream distribution system 6 according to the second embodiment, it is possible to improve the quality of information communication via the communication network in a short time. The reason is that the configuration included in the stream distribution system 6 according to the second embodiment includes the configuration included in the stream distribution system 4 according to the first embodiment.

<Third Embodiment>
Next, a third embodiment of the present invention based on the above-described first embodiment will be described.

In the following description, the characteristic part according to the present embodiment will be mainly described, and the same configurations as those in the above-described first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. To do.

The configuration of the stream distribution device 210 according to the third embodiment of the present invention will be described in detail with reference to FIG. FIG. 12: is a block diagram which shows the structure which the stream delivery apparatus 210 which concerns on the 3rd Embodiment of this invention has.

The stream distribution device 210 according to the third embodiment of the present invention includes a stream data input unit 11, an encoding unit 12, a transmission unit 13, an available bandwidth unit 14, a buffer amount estimation unit 15, and a delay model creation. It has a unit 16, a quality model creation unit 17, a bit rate model selection unit 18, a transmission delay estimation unit 19, and a bit rate information storage unit 21.

When the process of determining the bit rate model is executed, for example, in a time of 1 second or less, the stream distribution device 210 determines the bit rate model from the bit rate information stored in the bit rate information storage unit 21. It is necessary to execute the selected process in a short time. In the present embodiment, the number of bit rate models is smaller than that in the above-described embodiments, mainly for the purpose of realizing short-time processing.

ITU-T_G. According to 1070 and the like, in stream distribution, the higher the bit rate and the shorter the delay time represented by the delay model d(t), the higher the quality of distribution. In the delay model d(t), the transmission delay time dT(t) related to the communication network depends on the distance of the transmission path in the communication network. Therefore, in stream distribution, high-quality distribution is possible when the bit rate is equal to the available bandwidth and the required time dB(t) required for buffering in the delay model d(t) is 0.

In the present embodiment, the bit rate information storage unit 21 linearly increases (or decreases) from a certain bit rate to an available band and then the available band (or, as shown in FIG. 13). The bit rate model r(t), which is a value that is approximately the available band) is included. FIG. 13 is a diagram conceptually showing an example of the bit rate model. In FIG. 13, the horizontal axis represents the timing, and the right side indicates that the time advances. In FIG. 13, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate.

For convenience of explanation, it is assumed that the value of the bit rate model r(t) is r0 at the timing t0. The value of the available band C(t) is assumed to be c0 after the timing t0. However, it is assumed that r0>0 and c0>0.

In the example shown in FIG. 13, the value of the bit rate model r(t) is a2 (where a2>0) when the timing increases by 1, for example, in the period from the timing t0 to the timing t2. It is supposed to increase. In the example shown in FIG. 13, after the timing t2, the value of the bit rate model r(t) is the value c0 of the available band. That is, the bit rate model r(t) is the bit rate model shown in Expression A.
r(t)=a2×t+r0 (where t0≦t≦t2),
=c0 (however, t2<t)) (Equation A).

Therefore, the timing t2 is calculated according to Expression 7. That is,
Timing t2=(c0-r0)/a2... (Formula 7).

The bit rate information storage unit 21 stores, for example, a bit rate model in which at least one of r0 and a2 is different with respect to the bit rate model illustrated in FIG.

Among the bit rate models stored in the bit rate information storage unit 21, the bit rate model selection unit 18 sets the bit whose quality model is the maximum (or approximately maximum) in the period from the timing t0 to the timing “t0+T”. Select a rate model.

The more bit rate models stored in the bit rate information storage unit 21 (that is, the more combinations of a2 and r0 are stored), the higher the possibility that the maximum value of the quality model is. That is, as the number of bit rate models stored in the bit rate information storage unit 21 increases, the obtained user quality is more likely to increase.

The number of bit rate models stored in the bit rate information storage unit 21 may be determined based on the interval for selecting the bit rate models (that is, the time required for the selection processing). In this case, the stream distribution device 210 can determine the bit rate with high quality even when the timing for selecting the bit rate model is determined.

Further, the bit rate model selection unit 18 sets the bit rate model (that is, a2 and r0 in the present embodiment so that the data amount stored in the buffer becomes 0 (or approximately 0) at the timing t2. Group) may be selected. Specifically, a procedure in which the bit rate model selection unit 18 selects a bit rate model will be described.

For example, when the available bandwidth C(t) is constant at c0 in the period from timing t0 to timing (t0+T), the amount of data reduced from the buffer in the period from timing t0 to timing t2 is It is the difference between C(t) and the bit rate model r(t) (that is, the area of the region X). The bit rate model selection unit 18 calculates the area of the region X, for example, according to Expression 8. That is,
Area of region X = (c0-r0) x t2/2 (Equation 8).

When the amount of data stored in the buffer at the timing t0 is represented as B(t0), the bit rate model selection unit 18 establishes a condition that B(t0) is equal to the area of the region X, that is, a2 and r0. Select and. According to Equation 7 and Equation 8, a2 and r0 are related. That is, if either one of a2 and r0 is calculated, the other can also be calculated. Therefore, according to the stream distribution apparatus 210 according to the third embodiment, a shorter calculation time is required. Thus, it is possible to perform control with high sensation performance.

Next, effects of the stream distribution device 210 according to the third embodiment of the present invention will be described.

According to the stream distribution device 210 according to the third embodiment, it is possible to improve the quality of information communication via the communication network in a short time. This is because the configuration included in the stream distribution device 210 according to the third embodiment includes the configuration included in the stream distribution device 1 according to the first embodiment.

Further, according to the stream distribution device 210 according to the present embodiment, it is possible to further improve the quality of information communication in a short time. The reason for this is that the bit rate model stored in the bit rate information storage unit 21 is smaller than that in the first and second embodiments.

Further, according to the stream distribution device 210 according to the third embodiment, it is possible to realize communication with better quality. The reason for this is that, according to the bit rate model included in the bit rate information, a value that matches (or is similar to) the available bandwidth model representing the available bandwidth for the communication network is used after the timing t2. This is because the stream distribution device 210 can control communication. That is, the available bandwidth model represents the degree to which the communication bandwidth of the communication network 3 changes (is related) with the passage of time.

Further, according to the stream distribution device 210 according to the third embodiment, it is possible to improve the communication quality of information in a shorter time. The reason is that since the bit rate model is composed of polygonal lines, the stream distribution device 210 can calculate the parameters included in the bit rate model with a small amount of calculation.

In the present embodiment, the bit rate model is stored in the bit rate information storage unit 21, but the stream distribution device 210 according to the third embodiment stores the bit rate model in accordance with the above-described equation and the like. You may have the parameter calculation part which calculates.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention based on the above-described first embodiment will be described.

In the following description, the characteristic part according to the present embodiment will be mainly described, and the same configurations as those in the above-described first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. To do.

The configuration of the stream distribution device 220 according to the fourth embodiment of the present invention will be described in detail with reference to FIG. FIG. 14: is a block diagram which shows the structure which the stream delivery apparatus 220 which concerns on the 4th Embodiment of this invention has.

A stream distribution device 220 according to the fourth embodiment of the present invention includes a stream data input unit 11, an encoding unit 12, a transmission unit 13, an available bandwidth unit 14, a buffer amount estimation unit 15, and a delay model creation. It has a unit 16, a quality model creation unit 17, a bit rate model selection unit 18, a transmission delay estimation unit 19, and a bit rate information storage unit 22.

In the present embodiment, in the bit rate information storage unit 22, for example, as illustrated in FIG. 15, the value of the bit rate model is r0 at timing t0, and the available bandwidth C( A bit rate model that is an exponential function that converges to t) is stored. FIG. 15 is a diagram conceptually illustrating an example of the bit rate model. In FIG. 15, the horizontal axis represents the timing, and the right side indicates that the time advances. In FIG. 15, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate.

Specifically, the bit rate information storage unit 22 stores the bit rate model exemplified in Expression 9. That is,
r(t)=(r0−c0)×exp(b×t)+c0 (Equation 9),
However, b<0, 0<r0≦c0. exp(x) represents an exponential function e ^x related to the Napier number e (similarly in the following mathematical expressions).

The bit rate information storage unit 22 stores, for example, a bit rate model in which at least one of b and a2 is different from the bit rate model as illustrated in FIG.

Among the bit rate models stored in the bit rate information storage unit 22, the bit rate model selection unit 18 has the maximum (or approximately maximum) bit rate model in the period from the timing t0 to the timing “t0+T”. Select a model.

Next, effects of the stream distribution device 220 according to the fourth embodiment of the present invention will be described.

In the present embodiment, as in the third embodiment, the number of bit rate models stored in the bit rate information storage unit 22 is small, so that the time required for the process of selecting the bit rate model is short.

The bit rate model is represented by a straight line in the third embodiment, and the bit rate model is represented by an exponential function in the fourth embodiment. It is not limited to the example. The bit rate model may be a function defined by the timing t and one or more parameters. Further, the bit rate information storage unit 22 may store bit rate information including a plurality of types of bit rate models, such as a set of straight lines and exponential functions.

Next, effects of the stream distribution device 220 according to the fourth embodiment of the present invention will be described.

According to the stream distribution device 220 of the fourth embodiment, it is possible to improve the quality of information communication via the communication network in a short time. This is because the configuration included in the stream distribution device 220 according to the fourth embodiment includes the configuration included in the stream distribution device 1 according to the first embodiment.

Although the bit rate model is stored in the bit rate information storage unit 22 in the present embodiment, the stream distribution device 220 according to the fourth embodiment stores the bit rate model in accordance with the above-described equation and the like. You may have the parameter calculation part which calculates.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention based on the above-described first embodiment will be described.

In the following description, the characteristic part according to the present embodiment will be mainly described, and the same configurations as those in the above-described first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. To do.

The configuration of the stream distribution device 230 according to the fifth embodiment of the present invention will be described in detail with reference to FIG. FIG. 16 is a block diagram showing the configuration of the stream distribution device 230 according to the fifth embodiment of the present invention.

A stream distribution device 230 according to the fourth embodiment of the present invention includes a stream data input unit 11, an encoding unit 12, a transmission unit 13, an available bandwidth unit 14, a buffer amount estimation unit 15, and a delay model creation. It has a unit 16, a quality model creation unit 17, a bit rate model selection unit 18, a transmission delay estimation unit 19, and a bit rate information storage unit 23.

In the present embodiment, the bit rate information storage unit 23 stores in the bit rate information storage unit 23 based on the bit rate immediately before the timing t0 (for example, the value of the bit rate immediately before the timing t0, as illustrated in FIGS. 17 to 19). The bit rate model having the value r0 that is determined is stored. 17 to 19 are diagrams conceptually illustrating an example of the bit rate model. 17 to 19, the horizontal axis represents the timing, and the right side indicates that the time advances. 17 to 19, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate.

Specifically, the bit rate model illustrated in each drawing will be described with reference to FIGS. 17 to 19. For convenience of explanation, in the case of the examples shown in FIGS. 17 to 19, it is assumed that the available band C(t) is constant in the available band c0 at the timing t0.

The bit rate information storage unit 23 stores the bit rate model shown in Expression 10 (illustrated in FIG. 17). That is,
r(t)=a1×t+r0 (where t0≦t≦t1),
a2×(t−t1)+a1×t2+r0 (where t1<t≦t2),
C(t) (however, t2<t)... (Formula 10).

For convenience of description, the bit rate at the timing t0 is represented as r0. The bit rate model is r0 at the timing t0 and decreases at the slope a1 (where a1<0) in the period from the timing t0 to the timing t1. The bit rate model is assumed to increase with a slope a2 (where a2<0) in the period from timing t1 to timing t2. After the timing t2, the bit rate model has a value representing the available band c0 (or the approximately available band c0).

In the bit rate information storage unit 23, for example, in the bit rate model as illustrated in FIG. 17, at least one of a1, a2, and t1 (t0≦t1≦t0+T) is different. Stores the rate model.

Among the bit rate models stored in the bit rate information storage unit 23, the bit rate model selection unit 18 has the maximum (or approximately maximum) bit rate model in the period from the timing t0 to the timing “t0+T”. Select a model.

The more bit rate models stored in the bit rate information storage unit 23 (that is, the more combinations of a1, a2, and t1), the higher the possibility that the maximum value of the quality model will be. That is, the more bit rate models stored in the bit rate information storage unit 23, the higher the possibility that the obtained user quality will be.

The number of bit rate models stored in the bit rate information storage unit 23 may be determined based on the time required to select the bit rate model (that is, the time required for the selection process). In this case, the stream distribution apparatus 230 can determine the bit rate with high quality even when the timing for selecting the bit rate model is determined.

Further, the bit rate model selection unit 18 sets the bit rate model (that is, a1 and a2 in this embodiment so that the data amount stored in the buffer becomes 0 (or approximately 0) at the timing t2. And t1) may be selected. Specifically, a procedure in which the bit rate model selection unit 18 selects a bit rate model will be described.

The amount of data stored in the buffer (that is, the amount of buffer B(t)) is determined when the bit rate represented by the bit rate model r(t) is larger than the available bandwidth (that is, r(t)>C(t). )), and decreases when the bit rate represented by the bit rate model r(t) is less than the available bandwidth (that is, r(t)<C(t)). Referring to FIG. 17, the amount of data in which the bit rate represented by the bit rate model r(t) exceeds the available band represents the area of the region a. The amount of data whose bit rate represented by the bit rate model r(t) is smaller than the available bandwidth represents the area of the region b. Therefore, the bit rate model selection unit 18 calculates any two values out of a1, a2, and t1. After that, the bit rate model selection unit 18 sets the data amount stored in the buffer (that is, the buffer amount B(t0)) at the timing t0 and the data amount stored in the buffer (that is, the area of the region a). The remaining one value is calculated according to the conditional expression that the sum is equal to the amount deleted from the buffer (that is, the area of the region b). In this case, the bit rate model selection unit 18 calculates the remaining one value according to the conditional expression “B(t0)+(area of area a)=(area of area b)”.

In addition, the bit rate information storage unit 23 may store a bit rate model in which the available bandwidth C(t) drops below a predetermined rate. The predetermined ratio is a specific value such as 90% or 80%. The smaller the predetermined ratio is, the faster the delay in the communication network 3 is eliminated by the stream distribution device 230 according to the present embodiment. Therefore, according to the stream distribution device 230, communication with good quality can be realized in a shorter time. The reason for this is that the stream distribution device 230 selects a bit rate model that drops below a predetermined ratio of the available bandwidth, so that delay in the communication network is eliminated early. As a result of the delay in the communication network 3 being eliminated at an early stage, the value of the quality model is increased at an early stage, so that according to the stream distribution device 230, communication with good quality can be realized in a shorter time.

Next, the bit rate model stored in the bit rate information storage unit 23 will be described with reference to FIG. The bit rate information storage unit 23 stores the bit rate model (illustrated in FIG. 18) represented by the above-described expression A. However, the bit rate r0 at the timing t0 is a value calculated based on the bit rate immediately before the timing t0 (for example, the same value as the bit rate immediately before the timing t0, or a similar value).

The description of the formula A is the same as the above description, and thus the description thereof will be omitted in the present embodiment.

Next, the bit rate model stored in the bit rate information storage unit 23 will be described with reference to FIG. The bit rate information storage unit 23 stores the bit rate model shown in Expression 11 (illustrated in FIG. 19). That is,
r(t)=a1×t+r0 (where t0≦t≦t1),
a2×(t−t1)+a1×t2+r0 (where t1<t≦t2),
C(t) (however, t2<t)... (Formula 11).

For convenience of description, the bit rate at the timing t0 is represented as r0. The bit rate model has a value r0 at the timing t0, and it is assumed that the bit rate model decreases at the slope a1 (where a1<0) in the period from the timing t0 to the timing t1. The bit rate model is assumed to increase with a slope a2 (where a2<0) in the period from timing t1 to timing t2. After the timing t2, the bit rate model has a value that becomes the available band c0 (or approximately the available band c0). However, the bit rate model r(t) has a value smaller than the available bandwidth C(t) (that is, r(t)<C(t)) in the period from the timing t0 to the timing (t0+T).

In the bit rate information storage unit 23, for example, in a bit rate model as illustrated in FIG. 19, at least one of a1, a2, and t1 (t0≦t1≦t0+T) is different. Stores the rate model.

Among the bit rate models stored in the bit rate information storage unit 23, the bit rate model selection unit 18 has the maximum (or approximately maximum) bit rate model in the period from the timing t0 to the timing “t0+T”. Select a model.

The more bit rate models stored in the bit rate information storage unit 23 (that is, the more combinations of a1, a2, and t1), the higher the possibility that the maximum value of the quality model will be. That is, the more bit rate models stored in the bit rate information storage unit 23, the higher the possibility that the obtained quality will be.

The number of bit rate models stored in the bit rate information storage unit 23 may be determined based on the time required for the process of selecting the bit rate model (that is, the time required for the selection process). In this case, the stream distribution device 230 can determine the bit rate with high quality even if the time required to select the bit rate model is determined.

Further, the bit rate model selection unit 18 sets the bit rate model (that is, a1 and a2 in the present embodiment so that the data amount stored in the buffer becomes 0 (or substantially 0) at the timing t2. And t1) may be selected. Specifically, a procedure in which the bit rate model selection unit 18 selects a bit rate model will be described.

In the example shown in FIG. 19, the bit rate model r(t) is smaller than the available bandwidth C(t) in the period from the timing t0 to the timing (t0+T), so the amount of data stored in the buffer is , Decrease in the period. The bit rate model selection unit 18 calculates any two values among a1, a2, and t1. After that, the bit rate model selection unit 18 says that the amount of data stored in the buffer at the timing t0 (that is, the buffer amount B(t0)) is equal to the amount deleted from the buffer (that is, the area of the region Y). The remaining one value is calculated according to the conditional expression. In this case, the bit rate model selection unit 18 calculates the remaining one value according to the conditional expression “B(t0)=(area of the region Y)”.

In addition, the bit rate information storage unit 23 may store a bit rate model regarding a case where the amount of data stored in the buffer (that is, the buffer amount B(t0)) is larger than a predetermined value. Good. In such a bit rate model, the bit rate is temporarily reduced further than the available band and then increased to the available band, so that the user experience quality is improved to a greater extent. Therefore, the stream distribution device 230 according to the present embodiment has an effect that there is a high possibility that the user experience quality is improved by reducing the abrupt change in the bit rate.

In the fifth embodiment, a model in which straight lines are continuously connected (that is, a model represented by a polygonal line) is illustrated as an example of the bit rate model, but the bit rate model is limited to the above example. Not done. The bit rate model may be a function related to timing.

Next, effects of the stream distribution device 230 according to the fifth embodiment of the present invention will be described.

According to the stream distribution device 230 of the fifth embodiment, it is possible to improve the quality of information communication via the communication network in a short time. This is because the configuration included in the stream distribution device 230 according to the fifth embodiment includes the configuration included in the stream distribution device 1 according to the first embodiment.

Furthermore, according to the stream distribution device 230 of the fifth embodiment, communication of higher quality information can be realized in a short time. The reason for this is that the possibility of quality deterioration at the timing t0 is reduced. For example, the stream distribution device 230 sets the bit rate r0 at the timing t0 to the same value (or a similar value) as the bit rate immediately before the timing t0, so that the quality becomes poor at the timing t0. Reduce the likelihood.

Although the bit rate model is stored in the bit rate information storage unit 23 in the present embodiment, the stream distribution device 230 according to the fifth embodiment stores the bit rate model in accordance with the above-described formula and the like. You may have the parameter calculation part which calculates.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention based on the above-described first embodiment will be described.

In the following description, the characteristic part according to the present embodiment will be mainly described, and the same configurations as those in the above-described first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. To do.

The configuration of the stream distribution device 240 according to the sixth embodiment of the present invention will be described in detail with reference to FIG. FIG. 20: is a block diagram which shows the structure which the stream delivery apparatus 240 which concerns on the 6th Embodiment of this invention has.

The stream distribution device 240 according to the sixth embodiment of the present invention includes a stream data input unit 11, an encoding unit 12, a transmission unit 13, an available bandwidth unit 14, a buffer amount estimation unit 15, and a delay model creation. It includes a unit 16, a quality model creation unit 17, a bit rate model selection unit 18, a transmission delay estimation unit 19, and a bit rate information storage unit 24.

In the present embodiment, the bit rate information storage unit 24 stores, for example, a bit rate model (illustrated in FIG. 21) calculated based on two exponential functions, as shown in Expression 12 described later. There is. FIG. 21 is a diagram conceptually showing an example of the bit rate model. In FIG. 21, the horizontal axis represents timing, and the right side indicates that time advances. In FIG. 21, the vertical axis represents the bit rate, and the higher the value, the higher the bit rate.

Specifically, the bit rate model will be described with reference to FIG. For convenience of explanation, in the case of the example shown in FIG. 21, it is assumed that the available band C(t) is constant in the available band c0 at the timing t0.

The bit rate information storage unit 24 stores the bit rate model shown in Expression 12 (illustrated in FIG. 21). That is,
r(t)=a1×exp(b1×t)+c0+a2×exp(d×b2×t) (Equation 12),
However, a1<0, a2≧0, b1<0, b2<0, d>1, a1+a2+C=r0.

In the bit rate model r(t) shown in Expression 12, “a1×exp(b1×t)+c0+a2” is set to c0 as in the fourth embodiment when the timing t is a sufficiently large value. It is an exponential function that converges. That is, when a2 is 0, formula 12 represents a formula equivalent to formula 9 shown in the fourth embodiment. Further, in the bit rate model r(t) shown in Expression 12, “a2×exp(d×b2×t)” is an exponential function that converges to 0 when the timing t is a sufficiently large value. is there. Also, “a2×exp(d×b2×t)” converges more rapidly than “a1×exp(b1×t)+c0+a2” when d>1. Therefore, as illustrated in FIG. 21, the bit rate model shown in Expression 12 is a function in which the value of the bit rate model decreases once as time elapses and then converges to the available band c0. ..

In the bit rate information storage unit 24, for example, with respect to the bit rate model as illustrated in FIG. 21, a bit rate in which at least one of a1, a2, b1, b2, and d is different. Contains the model.

Among the bit rate models stored in the bit rate information storage section 24, the bit rate model selection section 18 has a maximum (or approximately maximum) quality rate in the period from the timing t0 to the timing “t0+T”. Select a model.

The more bit rate models stored in the bit rate information storage unit 24 (that is, the more combinations of a1, a2, b1, b2, and d), the larger the maximum value of the quality model may be. Is high. That is, the more bit rate models stored in the bit rate information storage unit 24, the higher the possibility that the obtained user quality is likely to be.

The number of bit rate models stored in the bit rate information storage unit 24 may be determined based on the time required to select the bit rate model (that is, the time required for the selection process). In this case, the stream distribution device 240 can determine the bit rate with high quality even when the timing for selecting the bit rate model is determined.

In the sixth embodiment, a model in which exponential functions are continuously connected (that is, a model represented by a polygonal line) is illustrated as an example of the bit rate model. Not limited. The bit rate model may be a function related to timing.

Next, effects of the stream distribution device 240 according to the sixth embodiment of the present invention will be described.

According to the stream distribution device 240 according to the sixth embodiment, it is possible to improve the quality of information communication via a communication network in a short time. This is because the configuration included in the stream distribution device 240 according to the sixth embodiment includes the configuration included in the stream distribution device 1 according to the first embodiment.

Furthermore, according to the stream distribution device 240 according to the sixth embodiment, it is possible to improve the communication quality of higher quality information in a short time. This is because the bit rate model stored in the bit rate information storage unit 24 is set as the sum of exponential functions, and thus the possibility that the bit rate will change suddenly is low. As a result, according to the stream distribution apparatus 240 according to the sixth embodiment, the quality is unlikely to deteriorate, and thus it is possible to realize communication of higher quality information in a short time.

Although the bit rate model is stored in the bit rate information storage unit 24 in the present embodiment, the stream distribution device 240 according to the sixth embodiment stores the bit rate model in accordance with the above-described equations and the like. You may have the parameter calculation part which calculates.

<Seventh Embodiment>
Next, a seventh embodiment of the present invention will be described.

In the following description, the characteristic part according to the present embodiment will be mainly described, and the same configurations as those in the above-described first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. To do.

The configuration of the bit rate indicating device 71 according to the seventh embodiment of the present invention will be described in detail with reference to FIG. FIG. 22 is a block diagram showing the configuration of the bit rate indicating device 71 according to the seventh embodiment of the present invention.

The bit rate instructing device 71 according to the seventh embodiment of the present invention includes a quality model creating unit 72, a delay model creating unit 73, and a bit rate instructing unit 74.

The bit rate indicating device 71 can be connected (or communication connected) with the control device 75 that controls the communication network 3. The bit rate instruction device 71 can refer to the bit rate information 76 including a plurality of bit rate models as described with reference to FIG. 5, FIG. 13, FIG. 15, FIG. 17 to FIG. it can. That is, the bit rate instructing device 71 refers to the bit rate information 76 including a plurality of bit rate models representing the extent to which the amount of data per unit time of data communicated via the communication network 3 changes over time. can do.

The delay model creating unit 73 delays time when data is communicated via the communication network 3 based on the difference between the bit rate model included in the bit rate information 76 and the available bandwidth model as described above. Create a delay model that can determine That is, the delay model creation unit 73, based on the difference between the bit rate model included in the bit rate information 76 and the available bandwidth model that represents the degree to which the communication bandwidth of the communication network 3 changes over time, Create the delay model. The delay model creation unit 73 creates a delay model relating to the bit rate model and the available band function according to, for example, Expression 1 to Expression 5 or the like. The delay model represents the degree to which the delay time of communication via the communication network 3 changes over time.

Next, the quality model creating unit 72 creates a quality model capable of determining communication quality when delay occurs according to the delay model created by the delay model creating unit 73 and the bit rate is controlled according to the bit rate model. , For example, according to the method disclosed in Patent Document 1 or the like. In this case, the quality model creating unit 72 creates the quality model using the delay model created by the delay model creating unit 73 and the bit rate model.

The quality model creation unit 72 and the delay model creation unit 73 execute the above-described processing for each bit rate model included in the bit rate information 76, for example.

The bit rate instructing unit 74 selects, from the bit rate models included in the bit rate information 76, a bit rate model in which the quality model created by the quality model creating unit 72 has a larger value. That is, the bit rate instructing unit 74 selects, from the bit rate models included in the bit rate information 76, a bit rate model whose quality determined according to the quality model is large for a certain period. The bit rate instruction unit 74 transmits request information requesting control of the communication speed according to the selected bit rate model to the control device 75 controlling the communication network 3.

The control device 75 receives the request information transmitted by the bit rate instruction unit 74, and controls communication in the communication network 3 according to the bit rate model instructed by the received request information.

The delay model creating unit 73 can be realized by using the function of the delay model creating unit 16 shown in FIG. 2, for example. The quality model creation unit 72 can be realized using, for example, the function of the quality model creation unit 17 shown in FIG. The bit rate instructing unit 74 can be realized by using the function of the bit rate model selecting unit 18 and the function of the transmitting unit 13 shown in FIG. In summary, the bit rate instruction device 71 includes the stream distribution device 1 shown in FIG. 2, the stream distribution device 210 shown in FIG. 12, the stream distribution device 220 shown in FIG. 14, and the stream shown in FIG. It can be realized by using the function of the distribution device 230, the stream distribution device 240 shown in FIG.

Next, effects of the bit rate indicating device 71 according to the seventh embodiment will be described.

According to the bit rate instruction device 71 according to the seventh embodiment, it is possible to improve the communication quality of information in a short time via the communication network. The reason for this is that it is possible to calculate the bit rate over a longer period than the communication device disclosed in Patent Document 1 and control communication according to the calculated bit rate. Therefore, the number of times communication is controlled is reduced as compared with the communication device disclosed in Patent Document 1, and thus the bit rate instruction device 71 according to the present embodiment can realize communication of high-quality information in a short time. You can

(Example of hardware configuration)
The above-described stream distribution device according to the first to sixth embodiments of the present invention or the bit rate instruction device according to the seventh embodiment is replaced with one calculation processing device (information processing device, computer). A configuration example of the hardware resource realized by using will be described. However, the stream distribution device or the bit rate instruction device may be realized physically or functionally by using at least two calculation processing devices. The stream distribution device or the bit rate instruction device may be realized as a dedicated device.

FIG. 23 is a schematic hardware configuration example of a stream distribution device according to the first to sixth embodiments or a bit rate instruction device according to the seventh embodiment. It is a block diagram shown. The calculation processing device 80 includes a central processing unit (Central_Processing_Unit, hereinafter referred to as “CPU”) 81, a memory 82, a disk 83, a non-volatile recording medium 84, a communication interface (hereinafter referred to as “communication IF”) 87, and It has a display 88. The calculation processing device 80 may be connectable to the input device 85 and the output device 86. The calculation processing device 80 can send and receive information to and from other calculation processing devices and communication devices via the communication IF 87.

The non-volatile recording medium 84 is, for example, a compact disc (Compact_Disc) or a digital versatile disc (Digital_Versatile_Disc) that can be read by a computer. The non-volatile recording medium 84 may be a universal serial bus memory (USB memory), a solid state drive (Solid_State_Drive), or the like. The non-volatile recording medium 84 retains such a program even when power is not supplied, and makes it portable. The nonvolatile recording medium 84 is not limited to the above-mentioned medium. Further, instead of the nonvolatile recording medium 84, the program may be carried via the communication IF 87 and the communication network.

That is, the CPU 81 copies a software program (computer program: hereinafter simply referred to as “program”) stored in the disk 83 to the memory 82 when executing, and executes arithmetic processing. The CPU 81 reads the data necessary for executing the program from the memory 82. When the display is required, the CPU 81 displays the output result on the display 88. When the output to the outside is necessary, the CPU 81 outputs the output result to the output device 86. When the program is input from the outside, the CPU 81 reads the program from the input device 85. The CPU 81 uses the stream distribution in the memory 82 corresponding to the function (processing) represented by each unit shown in FIG. 1, FIG. 2, FIG. 9, FIG. 12, FIG. 14, FIG. 16, FIG. The program (FIGS. 3, 4, and 11) or the bit rate instruction program is interpreted and executed. The CPU 81 sequentially executes the processing described in each of the above-described embodiments of the present invention.

That is, in such a case, it can be understood that the present invention can be realized by the stream distribution program or the bit rate instruction program. Furthermore, the present invention can be understood to be realized by a computer-readable non-volatile recording medium in which the stream distribution program or the bit rate instruction program is recorded.

The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above embodiment. That is, the present invention can apply various aspects that can be understood by those skilled in the art within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 stream distribution device 2 stream receiving device 3 communication network 4 stream distribution system 11 stream data input unit 12 encoding unit 13 transmission unit 14 available bandwidth unit 15 buffer amount estimation unit 16 delay model creation unit 17 quality model creation unit 18 bit rate model Selection unit 19 Transmission delay estimation unit 20 Bit rate information storage unit 5 Communication network 6 Stream distribution system 51 Base station device 52 Mobile core network 53 Internet 131 Transmission buffer 21 Bit rate information storage unit 210 Stream distribution device 22 Bit rate information storage unit 220 Stream distribution device 23 Bit rate information storage unit 230 Stream distribution device 24 Bit rate information storage unit 240 Stream distribution device 71 Bit rate instruction device 72 Quality model creation unit 73 Delay model creation unit 74 Bit rate instruction unit 75 Control device 76 Bit rate information 80 Calculation processing device 81 CPU
82 memory 83 disk 84 non-volatile recording medium 85 input device 86 output device 87 communication IF
88 displays

Claims (10)

The bit rate model in the bit rate information including a plurality of bit rate models representing the extent to which the amount of data per unit time relating to the data communicated via the communication network changes over time, and the communication of the communication network Create a delay model that represents the degree to which the delay time of communication performed via the communication network changes with time, based on the difference from the available bandwidth model that represents the degree to which the band changes with time. Delay model creating means to
Quality model creating means for creating a quality model representing the degree of the communication quality changing over time based on the delay model and the bit rate model,
Based on the quality represented by the created quality model, among the plurality of bit rate models included in the bit rate information, the quality in a certain period follows a bit rate model larger than other bit rate models. , A bit rate instructing means for instructing a control device controlling the communication so as to control the amount of data per unit time. The bit rate according to claim 1, wherein the bit rate instruction unit selects, from the bit rate information, the bit rate model in which the quality represented by the quality model is maximum or substantially maximum in the certain period. Pointing device. Further comprising a bit rate information storage unit storing the bit rate information,
The bit rate instruction device according to claim 1 or 2, wherein the bit rate information includes a value that is the same as or similar to the communication band determined from the available band model after the first timing. The bit rate according to claim 3, wherein the bit rate information includes a bit rate model that drops below a predetermined ratio of the communication band determined by the available band model at a second timing before the first timing. Pointing device. The bit rate instruction device according to claim 3 or 4, wherein the bit rate model included in the bit rate information is information indicating a polygonal line formed of a plurality of straight lines. The bit rate model has a negative slope during the period up to the second timing, has a positive slope during the period from the second timing to the first timing, and has a zero slope after the first timing. Or almost 0
The bit rate indicating device according to claim 4 .
The condition that the amount of data stored in the buffer in which the data to be processed in the communication delayed in the communication network is stored in the first-in first-out manner is 0 or almost 0 at the first timing Parameter calculating means for calculating the positive slope, the negative slope, and the second timing that are satisfied as a parameter, and storing the bit rate model represented by the calculated parameter in the bit rate information storage means. The bit rate indicating device according to claim 6, further comprising: 8. The bit rate information includes a bit rate model represented by using an exponential function that approaches the communication band represented by the available band model as time passes. The described bit rate indicating device. The bit rate model in the bit rate information including a plurality of bit rate models representing the extent to which the amount of data per unit time relating to the data communicated via the communication network changes over time, and the communication of the communication network Creates a delay model that represents the degree to which the delay time of communication performed via the communication network changes with time, based on the difference from the available bandwidth model that represents the degree to which the band changes with time. Then
The quality of the communication, the quality model representing the degree of transition over time, based on the delay model and the bit rate model,
Based on the quality represented by the created quality model, among the plurality of bit rate models included in the bit rate information, the quality in a certain period follows a bit rate model larger than other bit rate models. A bit rate instructing method for instructing a control device controlling the communication network to control the amount of data per unit time. The bit rate model in the bit rate information including a plurality of bit rate models representing the extent to which the amount of data per unit time relating to the data communicated via the communication network changes over time, and the communication of the communication network Create a delay model that represents the degree to which the delay time of communication performed via the communication network changes with time, based on the difference from the available bandwidth model that represents the degree to which the band changes with time. Delay model creation function to
A quality model creating function for creating a quality model representing the degree of the communication quality changing with time, based on the delay model and the bit rate model,
Based on the quality represented by the created quality model, among the plurality of bit rate models included in the bit rate information, the quality in a certain period follows a bit rate model larger than other bit rate models. A bit rate instruction program for causing a computer to realize a bit rate instruction function for instructing a control device controlling the communication network so as to control the amount of data per unit time.

Images