WO2018235697A1 - Transmission apparatus, communication system, communication method, and recording medium - Google Patents

Abstract

The throughput measurement unit (104) measures the throughput of communication with the reception terminal (2), and the division pattern generation unit (105) is configured with a plurality of division times by dividing a predetermined time. A plurality of patterns are generated, and the QoE calculation unit (106) calculates the perceived quality of the image from the predicted value of the future throughput for each pattern generated by the divided pattern generation unit (105), and the parameter determination unit (107 ) Determines the coding parameter for each division time of one pattern that maximizes the quality of perceived video.

Description

Transmission apparatus, communication system, communication method, and recording medium

The present invention relates to a transmitting apparatus, a communication system, a communication method, and a recording medium, and, for example, to a transmitting apparatus that transmits compressed video data via a network.

The throughput of communication via a best effort network such as Long Term Evolution (LTE) or Wi-Fi (registered trademark) may vary greatly. Therefore, there is a need for a technique for dynamically changing coding parameters for compressing video data in accordance with fluctuations in communication throughput.

The encoding parameters include, for example, bit rate, frame rate, and GOP (Group of picture) size (or key frame interval). The coding parameters can be changed by resetting the codec. The smaller the GOP size, the more granular the bit rate can be controlled.

The voice synthesizer (transmitting device) described in Patent Document 1 improves the image quality of video by increasing the GOP size of video data when the loss rate (loss rate of packets) is small, that is, when the throughput is high. Plan. On the other hand, when the loss rate is large, that is, when the throughput is low, the GOP size of video data is reduced. Thus, the speech synthesizer described in Patent Document 1 can control the bit rate with high granularity.

JP 2005-151600 A

"Video Streaming Control by Predictive Stochastic Diffusion of TCP Throughput" Yoshida Yoshida et al. Internet Conference 2011 (IC2011) (Oct. 27, 2011) Constructing Stochastic Model of TCP Throughput on Basis of Stationarity Analysis, Hiroshi Yoshida et al. Global Communications Conference (GLOBECOM), 2013 IEEE, date of conference: 9-13 Dec. 2013

However, in the communication method by the speech synthesizer (transmitting device) described in Patent Document 1, the influence of the combination of the GOP size and the bit rate on QoE (Quality of Experience) is not taken into consideration. Therefore, the QoE may be significantly reduced by the combination of the GOP size and the bit rate.

For example, if the transmitting apparatus described in Patent Document 1 reduces the GOP size to control the bit rate with high granularity, the control of the code amount may be broken and distortion (block noise) may occur in the block. There is. Block noise greatly affects QoE.

An object of the present invention is to improve the quality of experience of video transmitted through a network.

A transmitter according to an aspect of the present invention, in order to solve the above-mentioned problems, a throughput measuring means for measuring a throughput of communication with a receiving device, and a future based on the throughput measured by the throughput measuring means. According to the pattern generated by the pattern generation unit, the pattern generation unit configured to generate a plurality of patterns each configured by a plurality of division times by dividing the predetermined time by dividing the predetermined time. When video data is transmitted to the receiving terminal at a maximum bit rate that does not exceed the lower limit value of the future throughput predicted by the throughput prediction unit for each of the division times, the video data reproduced from the video data A bodily sensation quality calculating means for calculating a bodily sensation quality, and before the pattern generation means generates Among the plurality of patterns, pattern selection means for selecting one pattern that maximizes the sensory quality of the image calculated by the sensory quality calculation means, and the division according to the one pattern selected by the pattern selection means And parameter determining means for determining encoding parameters for the compression process of the video data for each time.

A communication method according to an aspect of the present invention measures the throughput of communication with a receiving device to solve the above problem, predicts the future throughput based on the measured throughput, and determines a predetermined time. By dividing, a plurality of patterns respectively formed of a plurality of division times are generated, and at each maximum division rate which does not exceed the lower limit value of the future throughput for each division time according to the generated patterns When video data is transmitted to the receiving apparatus, the sensory quality of the video to be reproduced is calculated from the video data, and one of the plurality of patterns is selected which makes the sensory quality of the video maximum. An encoding parameter for the compression process of the video data is determined for each of the division times according to the selected one pattern.

According to an aspect of the present invention, there is provided a recording medium that measures throughput of communication with a receiving device and predicts future throughput based on the measured throughput. Generating a plurality of patterns respectively configured by a plurality of division times by dividing a predetermined time, and not exceeding the lower limit value of the future throughput for each of the division times according to the generated patterns When video data is transmitted to the receiving apparatus at such a maximum bit rate, the sensory quality of the video to be reproduced from the video data is calculated, and the sensory quality of the video among the plurality of patterns is maximized. Selection of one pattern, and compression processing of the video data at each division time according to the selected one pattern. Storing a program for executing the method comprising: determining a coding parameter, to the computer.

An object of the present invention is to provide a transmission apparatus that improves the quality of experience of video transmitted through a network.

It is a block diagram of the communication system concerning Embodiment 1, and is a figure showing each composition of a transmitting terminal and a receiving terminal which constitute a communication system. It is a figure showing an example of a plurality of division time which constitutes predetermined time. It is a flowchart which shows the flow of QoE (Quality of Experience) calculation processing which the transmission terminal concerning Embodiment 1 performs. FIG. 5 is a diagram illustrating an example of throughput of communication between a transmitting terminal and a receiving terminal according to the first embodiment and an example of predicted future throughput. It is a figure which shows the example of the encoding parameter for every division time determined according to the prediction value of the future throughput. It is a figure which shows the other example of the encoding parameter for every division | segmentation time determined according to the prediction value of the future throughput. FIG. 5 is a sequence diagram showing a flow of communication between a transmitting terminal and a receiving terminal of the communication system according to Embodiment 1. FIG. 7 is a block diagram of a transmission terminal according to Embodiment 2. It is a figure which shows the hardware constitutions of the transmission terminal concerning Embodiment 3. FIG.

Embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1
(Communications system)
FIG. 1 is a block diagram of a communication system according to the first embodiment. As shown in FIG. 1, the communication system includes a transmitting terminal 1 and a receiving terminal 2. The transmitting terminal 1 and the receiving terminal 2 are terminal devices such as a personal computer or a smartphone. The transmitting terminal 1 and the receiving terminal 2 communicate via a network. The network of the communication system according to the first embodiment is the Internet, a mobile network, or the like, and has a heterogeneous structure.

(Transmission terminal 1)
As shown in FIG. 1, the transmitting terminal 1 includes an encoder 101, a transmitting unit 102, a data receiving unit 103, a throughput measuring unit 104, a division pattern generating unit 105, a QoE calculating unit 106, and a parameter determining unit 107. And have.

The encoder 101 compresses and encodes a video and outputs video data. The transmitting unit 102 transmits the video data compressed and encoded by the encoder 101 to the receiving terminal 2. The data receiving unit 103 receives data for measuring communication throughput from the receiving terminal 2. The throughput measuring unit 104 measures the throughput based on the data received by the data receiving unit 103.

The division pattern generation unit 105 generates a plurality of patterns (described later) each configured by a plurality of division times by dividing a predetermined time.

The QoE calculation unit 106 predicts the future throughput based on the throughput measured by the throughput measurement unit 104. In addition, the QoE calculation unit 106 calculates QoE, that is, the quality of experience of the user who views the video, for each of the patterns generated by the divided pattern generation unit 105.

The parameter determination unit 107 selects one pattern having the largest QoE calculated by the QoE calculation unit 106 from the plurality of patterns generated by the divided pattern generation unit 105, and based on the selected one pattern, Determine the coding parameters of

The details of processing executed by the divided pattern generation unit 105, the QoE calculation unit 106, and the parameter determination unit 107 will be described later in order.

(Receiver 2)
As shown in FIG. 1, the receiving terminal 2 includes a receiving unit 201 and a data transmitting unit 202. The receiving unit 201 receives the video data transmitted from the transmitting unit 102 of the transmitting terminal 1.

The data transmission unit 202 acquires or generates data necessary for calculating the throughput from the reception unit 201, and transmits the acquired or generated data to the transmission terminal 1.
(Division pattern generation unit 105)
The operation of the division pattern generation unit 105 of the transmission terminal 1 will be described. The division pattern generation unit 105 divides a predetermined time T from time 0 to a predetermined time T (> 0) at a maximum division number m (m is a natural number) or less. The predetermined time T and the maximum division number m may be any value. Alternatively, the predetermined time T and the maximum division number m may be set in advance by the user.

FIG. 2 shows an example of a plurality of patterns generated from the predetermined time T = t3 when the maximum division number m = 3. As shown in FIG. 2, in this case, the divided pattern generation unit 105 has four patterns: {0, t1, t2, t3}, {0, t2, t3}, {0, t1, t3}, Or generate {0, t3}. Here, 0 <t1 <t2 <t3 = T. In general, if the maximum division number is m, the total number of patterns is 2 ^ (m-1).

The pattern of the predetermined time T is hereinafter referred to as a set R_j (where 0 <= j <2 ^ (m-1)). Also, a set of the set R_j is called a set R. The elements of each set R_j are division times T_i (i = 0, 1, 2,...). For each set R_j, the number of elements, ie, division times T_i is different.

As shown in FIG. 2, when the maximum division number m = 3, the set R uses R = {R_0 = {T_0, T_1, T_2, T_3, using division time T_i (0 <= i <= 3). }, R_1 = {T_0, T_1, T_2}, R_2 = {T_0, T_1, T_2}, R_3 = {T_0, T_1}}.

Here, corresponding elements of different sets R_j of the set R are not necessarily the same. For example, referring to FIG. 2, the element T_1 of the set R_1 is t2, but the element T_1 of the set R_2 is t1. Also, the “distance” (on the time axis) between elements adjacent to each other is not necessarily constant.

For example, referring to FIG. 2, in the set R_0, the "distance" between elements is constant (where t1 = t2-t1 = t3-t2). On the other hand, in the set R_2, the "distance" between elements is not constant. Hereinafter, the “distance” between the element T_i and the element T_ {i-1} of the set R_j will be referred to as a division time (T_i−T_ {i-1}).

(QoE calculation unit 106)
The QoE calculation unit 106 calculates QoE, that is, the quality of sensation for each division time (T_i-T_ {i-1}). Usually, QoE is represented by a real number from 1 to 5. The lower the QoE, the lower the quality of sensation. On the other hand, the higher the QoE, the higher the quality of sensation.

The calculation function of QoE follows the standard on streaming quality of audiovisual media (for example, ITU-T P. 1201 created by the International Telecommunication Union / ITU Telecommunication Sector). In the first embodiment, the calculation function of QoE is represented as Q (b, g). Here, b is a bit rate, and g is a GOP size. That is, Q (b, g) depends on the bit rate and the GOP size.

In the present embodiment, the QoE calculation unit 106 calculates a function x (t) (t is time) representing the future throughput using the communication throughput prediction method. The communication throughput prediction method is a method of obtaining the expectation value and the variance of the probability density function representing the future throughput by analyzing the information on the past throughput along the time series. Techniques related to communication throughput prediction methods are described, for example, in Non-Patent Document 1 or Non-Patent Document 2. In the present embodiment, the description of the technology related to the communication throughput prediction method is omitted.

Also, the QoE calculation unit 106 determines the maximum bit rate from the throughput in the future. The maximum bit rate is the maximum bit rate that does not exceed the future throughput lower limit value represented by the function x (t). Therefore, the maximum bit rate matches the lower limit of the future throughput.

Alternatively, the QoE calculation unit 106 may calculate the lower limit value of the future throughput without using the communication throughput prediction method. For example, the QoE calculation unit 106 can predict the future throughput based on the measurement value of the throughput. In this case, the QoE calculation unit 106 may calculate the maximum bit rate b_i in the division time (T_i-T_ {i-1}) according to the following calculation formula.
b_i = a ^ i × x_0
Here, a is a sensitivity coefficient set in advance by the user. Further, x_0 is a measurement value of throughput at current time T_0 = 0. In general, the maximum bit rate decreases with time.

As long as the bit rate of the video data transmitted from the transmitting terminal 1 to the receiving terminal 2 does not exceed the lower limit value of the throughput in the future, the possibility that the reproduction of the video data on the receiving terminal 2 side is low is sufficiently low.
(How to calculate QoE)
A flow of a method of calculating QoE by the QoE calculating unit 106 according to the first embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the QoE calculation unit 106.

As shown in FIG. 3, the QoE calculation unit 106 first receives the set R from the divided pattern generation unit 105. Then, the QoE calculation unit 106 extracts one set R_j from the set R (S1). Initially j = 0.

If j <| R | (NO at S2), the QoE calculation unit 106 takes out the element (division time) T_i of R_j and initializes i (that is, i = 0) (S3). Here, | R | represents the number of elements of the set R. When j = | R | (YES in S2), the operation of the QoE calculation unit 106 ends.

In the case of i <| R_j | (NO in S4), the QoE calculation unit 106 calculates the division time (T_i−T_ {i) based on the function x (t) (t is time) representing the predicted throughput value calculated in advance. Calculate the maximum bit rate b_i in -1). Here, | R_j | represents the number of elements of the set R_j.

The QoE calculation unit 106 calculates the GOP size g_i in the division time (T_i-T_ {i-1}) according to the following calculation formula (S5).
g_i = f × (T_i-T_ {i-1})
Here, f is a frame rate. In the first embodiment, since the frame rate is constant, f is a constant.

Next, the QoE calculation unit 106 calculates QoE in each division time of the set R_j (S6). Hereinafter, QoE in the division time (T_i-T_ {i-1}) of the set R_j is represented as Q_j_i. Q_j_i is expressed as follows.
Q_j_i = Q (b_i, g_i) = Q (b_i, f × (T_i-T_ {i-1}))
As described above, the time represented by T_i differs depending on the set R_j. Therefore, it should be noted that Q_j_i takes different values depending on the set R_j.

After S6, 1 is added to i (S7), and the process returns to S4. If i = | R_j | (YES at S4), 1 is added to j (S8), and the process returns to S2.

According to the configuration of the first embodiment, since the maximum bit rate and the GOP size are optimally controlled based on the predicted throughput value, it is possible to suppress the decrease in QoE.

(Parameter determination unit 107)
The parameter determination unit 107 receives the set R generated by the divided pattern generation unit 105, and receives the QoE calculated by the QoE calculation unit 106, that is, Q_j_i.

The parameter determination unit 107 selects any one set R_j from all the sets R_j (0 <= j <| R |) of the set R according to the following calculation formula (1).

According to Equation (1), the parameter determination unit 107 weights Q_j_i for each division time (T_i-T_ {i-1}) of the set R_j by the division time (T_i-T_ {i-1}). The set R_j that maximizes the sum of values is selected.

The parameter determination unit 107 determines the maximum bit rate b_i and the GOP size g_i in each division time (T_i-T_ {i-1}) of the selected set R_j as a coding parameter for compression encoding of video data. .

(Encoder 101)
The encoder 101 receives information on the maximum bit rate and the GOP size from the parameter determination unit 107. Then, the encoder 101 resets the codec, and updates the coding parameters based on the received information of the maximum bit rate and the GOP size.

(Method of determining coding parameters)
The flow of a method in which the transmitting terminal 1 according to the first embodiment determines the coding parameters will be described with reference to FIGS. 4 and 5. FIG. 4 and FIG. 5 are graphs showing an example of time change of throughput. The horizontal axis t of the graph represents time, and the vertical axis b of the graph represents throughput. In FIG. 4, the solid line graph indicates the measured throughput value. Also, all three broken line graphs indicate predicted throughput values.

In FIG. 4, three broken line graphs respectively indicate “expected value” (y (t) in FIG. 4), “expected value + (plus) dispersion” (z (t)) in FIG. It corresponds to the expected value-(minus) variance "(x (t) in FIG. 4). Of these broken line graphs, "expected value-variance" x (t) represents the lower limit value of the predicted throughput.

When the maximum bit rate exceeds the lower limit value of the throughput, the reproduction of the video may be interrupted at the receiving terminal 2 side. Therefore, the maximum bit rate is limited so as not to exceed the lower limit of throughput.

It is assumed that the predetermined time T = 2 [sec] and the maximum division number m = 2. In FIG. 5, the maximum bit rates b_0 to b_2 for T_0 = 0 [sec] to T_2 = 2 [sec] are b_0 = 2 [Mbps], b_1 = 1.7 [Mbps], and b_2 = 1.3 [b], respectively. Mbps].

In this case, the division pattern generation unit 105 generates two patterns R_0 = {T_0, T_1, T_2} and R_1 = {T_0, T_2}}. In FIG. 5, T_0 = 0, T_1 = 1, and T_2 = 2.

The QoE calculation unit 106 calculates QoE for each division time of the set R_0, that is, Q_0_0 = Q (b_1, f × T_1) and Q_0_1 = Q (b_2, f × (T_2−T_1)). Also, QoE for the set R_1, that is, Q_1_0 = Q (b_2, f × T_2) is calculated. Here, the frame rate f is a constant.

After that, the parameter determination unit 107 calculates Q_j_i (0 <= i <| R_j |, 0 <= j <|) weighted by the division time (T_i−T_ {i−1}) based on the following formula (2). The sum of R |) is calculated.

In the case of R_0, the sum represented by equation (2) is Q_0_0 + Q_0_1. Also, in the case of R_1, the sum is 2 × Q_1_0. It can be said that QoE at a predetermined time T is larger as the sum is larger.

For example, it is assumed that Q_0_0 = 3.5, Q_0_1 = 3.2, and Q_1_0 = 3.3. In this case, the sum for R_0 is Q_0_0 + Q_0_1 = 3.5 + 3.2 = 6.7. Also, the sum for R_1 is 2 × Q_1_0 = 2 × 3.3 = 6.6.

Thus, the sum for R_0 is greater than the sum for R_1. Therefore, the parameter determination unit 107 selects the set R_0.

Also, the parameter determination unit 107 determines that the maximum bit rate b_1 = 1.7 [Mbps] in the division time (T_1-T_0) of the selected set R_0 and the maximum bit rate b_2 = 1 in the division time (T_2-T_1). The encoder 101 is notified of 3 [Mbps].

Further, parameter determination section 107 sets, as coding parameters, GOP size g = f × (T_1−T_0) in division time (T_1−T_0) and GOP size g = f × (division time (T_2−T_1)). T_2-T_1) also notifies the encoder 101.

In another example, it is assumed that Q_0_0 = 3.83, Q_0_1 = 3.72, and Q_1_0 = 3.81. In this case, the sum (see equation (2)) for R_0 is Q_0_0 + Q_0_1 = 3.83 + 3.72 = 7.55. On the other hand, the sum of R_1 is 2 × Q_1_0 = 7.62.

Thus, the sum for R_1 is greater than the sum for R_0. Therefore, the parameter determination unit 107 selects the set R_1. Also, the parameter determination unit 107 notifies the encoder 101 of the maximum bit rate b_2 = 1.3 [Mbps] in the division time (T_2−T_0) of the set R_1.

The parameter determination unit 107 also notifies the encoder 101 of the GOP size g = f × (T_2−T_0) in the division time (T_2−T_0) as the coding parameter.

Generally, the larger (smaller) the fluctuation of the throughput measurement value, the larger (smaller) the variance of the future throughput prediction value. FIG. 6 is a graph showing another example of the time change of throughput. The graph shown in FIG. 6 is smaller in fluctuation of the measured throughput than the graph shown in FIG. As a result, the variance of predicted throughput values is small. The graph x ′ (t) shown in FIG. 6, that is, the lower limit value of the predicted throughput, is gradually reduced as compared with the graph x (t) shown in FIG. In fact, in the graph x (t) shown in FIG. 5, x (t = 1) = 1.7 and x (t = 2) = 1.3, while in the graph x ′ (t) shown in FIG. It is x '(t = 1) = 1.8 and x' (t = 2) = 1.7.

According to the configuration of the first embodiment, it is possible to select an optimal combination of GOP size and bit rate so as to maximize the quality of experience (QoE) of the user. This is because QoE is calculated for each of a plurality of patterns that divide the predetermined time, and a pattern that maximizes QoE is selected. Further, according to the configuration of the first embodiment, even if the fluctuation of the throughput is large, it is possible to suppress the decrease in QoE. The reason is that since the maximum bit rate does not exceed the lower limit of the predicted throughput, there is a low possibility that the reproduction of the video will be interrupted.

(Communication method)
A communication method by the communication system according to the first embodiment will be described with reference to FIG. FIG. 7 is a sequence diagram showing a flow of each operation of the transmitting terminal 1 and the receiving terminal 2 when the transmitting terminal 1 and the receiving terminal 2 that make up the communication system communicate.

As shown in FIG. 7, the data transmitting unit 202 of the receiving terminal 2 transmits data related to throughput, in other words, data necessary for calculating the throughput, to the transmitting terminal 1 (S201).

For example, the data transmission unit 202 transmits information on the amount of video data received by the reception unit 201 of the reception terminal 2 per unit time and information on loss rate to the transmission terminal 1 as data on throughput.

The data reception unit 103 of the transmission terminal 1 receives data on throughput from the reception terminal 2. The throughput measuring unit 104 measures the throughput of communication between the transmitting terminal 1 and the receiving terminal 2 using the data received by the data receiving unit 103 (S101).

Next, the QoE calculation unit 106 of the transmission terminal 1 predicts the future throughput based on the throughput measured by the throughput measurement unit 104 (S102).

Also, the division pattern generation unit 105 of the transmission terminal 1 generates a pattern composed of a plurality of division times by dividing a predetermined time (for example, from 0 to t3 in FIG. 2) (S103).

Next, the QoE calculation unit 106 transmits an image to the receiving terminal 2 at a maximum bit rate that does not exceed the lower limit value of the future throughput predicted above for each division time according to the pattern generated by the division pattern generation unit 105. When data is transmitted, the sensory quality of the video to be reproduced is calculated from the video data (S104). The details of S104 have been described above with reference to FIG.

After that, the parameter determination unit 107 selects one pattern that maximizes the sensation quality calculated by the QoE calculation unit 106 among the plurality of patterns generated by the divided pattern generation unit 105 (S105).

Subsequently, the parameter determination unit 107 of the transmission terminal 1 determines a coding parameter for each division time according to one selected pattern (S106).

For example, in the example illustrated in FIG. 4, when the parameter determination unit 107 selects the set R_0 = {T_0, T_1, T_2} as the one pattern, the coding parameter (bit rate b_1) in the division time (T_1-T_0) is selected. And GOP size g = f × T_1) and coding parameters (bit rate b_2 and GOP size g = f × T_2) in division time (T_2−T_1) are determined, respectively.

The encoder 101 of the transmission terminal 1 compresses and encodes video data using the encoding parameter determined by the parameter determination unit 107 (S107).

The transmitting unit 102 of the transmitting terminal 1 transmits the video data compressed and encoded by the encoder 101 to the receiving terminal 2 (S108).

The receiving unit 201 of the receiving terminal 2 receives the compression-coded video data from the transmitting terminal 1 (S202). Thereafter, the flow returns to S201.

Second Embodiment
The minimum configuration of the present invention will be described as the second embodiment.

FIG. 8 is a schematic block diagram showing the configuration of the transmission terminal 3 according to the second embodiment. As shown in FIG. 8, the transmission terminal 3 according to the second embodiment includes a throughput measurement unit 301, a throughput prediction unit 302, a pattern generation unit 303, a sensation quality calculation unit 304, a pattern selection unit 305, and parameters. And a determination unit 306.

The throughput measurement unit 301 of the second embodiment corresponds to, for example, the throughput measurement unit 104 of the first embodiment. The throughput prediction unit 302 and the sensation quality calculation unit 304 of the second embodiment correspond to, for example, the QoE calculation unit 106 of the first embodiment.

The pattern generation unit 303 of the second embodiment corresponds to, for example, the divided pattern generation unit 105 of the first embodiment. The pattern selection unit 305 and the parameter determination unit 306 of the second embodiment correspond to, for example, the parameter determination unit 107 of the first embodiment.

The transmitting terminal 3 according to the second embodiment may further include components corresponding to the encoder 101 and the transmitting unit 102 provided in the transmitting terminal 1 of the first embodiment.

The throughput measuring unit 301 measures the throughput of communication with a receiving terminal (not shown). The throughput prediction unit 302 predicts the future throughput based on the throughput measured by the throughput measurement unit 301.

The pattern generation unit 303 generates a plurality of patterns each configured of a plurality of division times by dividing a predetermined time.

The perceptual quality calculation unit 304 transmits video data to the receiving terminal at the maximum bit rate that does not exceed the lower limit value of the future throughput predicted by the throughput prediction unit 302 every division time according to the pattern generated by the pattern generation unit 303. Is transmitted, the sensory quality of the video reproduced from the video data is calculated.

The pattern selection unit 305 selects, from among the plurality of patterns generated by the pattern generation unit 303, one pattern that maximizes the sensation quality of the image calculated by the sensation quality calculation unit 304.

The parameter determination unit 306 determines, for each division time corresponding to one pattern selected by the pattern selection unit 305, a coding parameter for compression processing of video data.

According to the configuration of the second embodiment, from among a plurality of patterns that define how to divide the predetermined time, one pattern that maximizes the quality of sensation of the video is specified, and based on the specified pattern , Determine the coding parameters. Therefore, in the video transmission via the network, the quality of experience of the video can be improved.

Third Embodiment
FIG. 9 is a block diagram showing the hardware configuration of the transmission terminal 4 according to the third embodiment. As shown in FIG. 9, the transmission terminal according to the third embodiment includes a central processing unit (CPU) 401, an encoder 402, and an interface 403. The transmission terminal 4 according to the present embodiment corresponds to, for example, the transmission terminal 1 according to the first embodiment or the transmission terminal 3 according to the second embodiment.

The CPU 401 implements the control function of the transmission terminal 4 according to the present embodiment. The encoder 402 corresponds to, for example, the encoder 101 of the first embodiment. The interface 403 corresponds to, for example, the transmission unit 102 and the data reception unit 103 of the first embodiment.

The transmission terminal 4 according to the present embodiment has a control function of the transmission terminal 1 according to the first embodiment (throughput measurement unit 104, division pattern generation unit 105, QoE calculation unit 106, parameter determination unit 107, and so on shown in FIG. A program for realizing all or part of the encoder 101) is recorded in a computer readable recording medium, and the program recorded in the recording medium is read by the CPU 401 and executed to perform processing of each part. It is also good. Here, the “computer system” includes an OS and hardware such as peripheral devices.

Alternatively, the transmitting terminal 4 according to the present embodiment has the control function of the transmitting terminal 3 according to the second embodiment (throughput measuring unit 301, throughput predicting unit 302, pattern generating unit 303, quality of experience calculating unit 304 shown in FIG. , A program for realizing all or part of the pattern selection unit 305 and the parameter determination unit 306) in a computer readable recording medium, and causing the CPU 401 to read the program recorded in the recording medium, and executing the program The processing of each part may be performed by doing this.

Here, “computer readable recording medium” means portable media such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), a CD (Compact Disc) -ROM, and a hard disk incorporated in a computer system. It refers to a storage device.

Further, the program read and executed by the CPU 401 may be for realizing a part of the above-described functions, and the above-described functions may be realized in combination with the program already recorded in the computer system. It may be

According to the configuration of the third embodiment, the same effect as that of the first embodiment or the second embodiment can be obtained.

As mentioned above, although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration for carrying out the present invention is not limited to these embodiments, and does not deviate from the gist of the present invention The design of the range is also included.

This application claims priority based on Japanese Patent Application No. 2017-119257 filed on Jun. 19, 2017, the entire disclosure of which is incorporated herein.

1 Transmission terminal (transmission device)
2 Receiving terminal (receiving device)
3 Sending terminal (sending device)
4 Sending terminal (sending device)
101 encoder 102 transmission unit (transmission means)
104 Throughput Measurement Unit (Throughput Measurement Means)
105 Division pattern generation unit (pattern generation unit, pattern selection unit)
106 QoE calculation unit (throughput prediction means, quality of experience calculation means)
107 Parameter determination unit (parameter determination means)
201 Receiver (Receiver)
202 Data Transmission Unit 301 Throughput Measurement Unit (Throughput Measurement Means)
302 Throughput prediction unit (throughput prediction means)
303 Pattern Generator (Pattern Generator)
304 Feeling Quality Calculator (Sensing Quality Calculator)
305 Pattern Selection Unit (Pattern Selection Means)
306 Pattern Determination Unit (Pattern Determination Unit)
402 encoder

Claims (10)

Throughput measuring means for measuring the throughput of communication with the receiving device;
A throughput prediction unit that predicts a future throughput based on the throughput measured by the throughput measurement unit;
Pattern generation means for generating a plurality of patterns each constituted by a plurality of division times by dividing a predetermined time;
The video data is transmitted to the receiving apparatus at a maximum bit rate which does not exceed the lower limit value of the future throughput predicted by the throughput prediction unit at each division time according to the pattern generated by the pattern generation unit. A sensory quality calculation means for calculating the sensory quality of the video to be reproduced from the video data;
Pattern selection means for selecting one of the plurality of patterns generated by the pattern generation means, the pattern having the highest perceived quality of the image calculated by the sensory quality calculation means;
Parameter determining means for determining encoding parameters for the compression process of the video data for each of the division times according to the one pattern selected by the pattern selecting means;
A transmitter having An encoder for compressing the video data using the coding parameter determined by the parameter determination unit;
Transmitting means for transmitting the video data compressed by the encoder to the receiving device;
The transmitter according to claim 1, further comprising: The transmission apparatus according to claim 1, wherein the encoding parameter includes at least a group of picture (GOP) size and a bit rate. The pattern generated by the pattern generation unit includes a plurality of division times T_i (i = 1, 2,...), And the plurality of division times T_i are the plurality of division times (T_i-T_ {i− 1)),
The sensory quality calculation means is based on a calculation function Q (b_i, g_i) including the maximum bit rate b_i and the GOP size g_i in each of the plurality of divided times (T_i-T_ {i-1}) as variables. Calculate the quality of experience,
The transmitting apparatus according to any one of claims 1 to 3, wherein the perceived quality calculated is represented by the following formula.

(Here, g_i = f * (T_i-T_ {i-1}), and f is a frame rate of the video data) The parameter determining means determines the maximum bit rate b_i in the division time (T_i-T_ {i-1}) selected by the pattern selection means in the division time (T_i-T_ {i-1}). The transmitter according to claim 4, characterized in that it is determined as the coding parameter. The throughput predicting means calculates an expected value and a variance of the future throughput based on the throughput measured by the throughput measuring means;
The transmitting apparatus according to any one of claims 1 to 5, wherein the feeling quality calculation means sets the expected value minus the variance calculated by the throughput prediction means as the lower limit value. A transmitter according to any one of claims 1 to 6,
A communication system including the receiving device. The receiving device is
Receiving means for receiving the video data from the transmitting device;
A throughput measurement data transmission unit for transmitting information for measuring the throughput to the transmission device by the throughput measurement unit;
The communication system according to claim 7, characterized in that: Measure the throughput of communication with the receiver,
Predict future throughput based on the measured throughput,
By dividing a predetermined time, a plurality of patterns each formed of a plurality of divided times are generated,
When video data is transmitted to the receiving apparatus at a maximum bit rate that does not exceed the lower limit value of the future throughput for each of the divided times according to the generated pattern, the video data reproduced from the video data Calculate quality of experience,
Among the plurality of patterns, one pattern which maximizes the quality of sensation of the image is selected,
The encoding parameter for the compression process of the video data is determined for each of the division times according to the selected one pattern.
Communication method. Measuring the throughput of communication with the receiving device;
Predicting future throughput based on the measured throughput;
Generating a plurality of patterns each configured of a plurality of division times by dividing the predetermined time;
When video data is transmitted to the receiving apparatus at a maximum bit rate that does not exceed the lower limit value of the future throughput for each of the divided times according to the generated pattern, the video data reproduced from the video data Calculating quality of experience,
Among the plurality of patterns, selecting one pattern that maximizes the perceived quality of the image;
Determining an encoding parameter for the compression process of the video data for each of the division times according to the selected one pattern;
A non-transitory recording medium storing a program that causes a computer to execute.

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