JP2011061533A - Content distribution system, sensory quality estimating apparatus, method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content distribution system suppressing deterioration of sensory quality of a user, in content distribution for carrying out content reproduction using a reproduction buffer. <P>SOLUTION: The content distribution means 102 distributes content data to a client 300. The client 300 has a reproduction buffer 301, and starts reproduction of the content data when content data of initial buffer time duration is buffered to the reproduction buffer 301. An integrated sensory quality estimating means 106 estimates the integrated sensory quality for which the influence given to the subjective sensory quality of a user by a buffering time indicating the time required for buffering the content data of initial buffer time duration to the reproduction buffer 301 is considered. A distribution parameter deciding means 101 decides a distribution parameter, based on the integrated sensory quality estimated by the integrated sensory quality estimating means 106. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a content distribution system, method, and program, and more particularly, to a content distribution system, method, and program that perform content distribution by selecting one of a plurality of distribution parameters.

  The present invention also relates to a sensation quality estimation apparatus, method, and program, and more particularly, to a sensation quality estimation apparatus, method, and program for estimating a user's experience quality when content is distributed to the user.

  The streaming distribution technique is a technique for streaming content. The streaming distribution system includes a content distribution server and a user terminal (client) such as a personal computer or a portable terminal device. The content distribution server converts the content file into an IP (Internet Protocol) packet. The content distribution server transmits the IP packetized content to the client via the network.

  When content is distributed via a network, the arrival interval of IP packets on the client side is often not constant due to network jitter (fluctuation) or the like. During the content reproduction, if the arrival of the IP packet is delayed from the reproduction time, the content reproduction is stopped. Therefore, normally, when performing streaming reproduction, a reproduction buffer is provided in the client, and the client performs reproduction after holding a certain amount or more of packets in the reproduction buffer.

  When the client starts streaming playback or resumes playback after performing a seek or the like, the client puts the arrived packet in the playback buffer. The client does not reproduce the content until a certain amount of data is accumulated in the reproduction buffer after the reproduction is started or after seeking. After the content data is stored in the reproduction buffer by a certain amount or more, the client reads the data in order from the beginning of the reproduction buffer and reproduces the content.

  When the reproduction buffer is used, even if the packet arrival is temporarily delayed due to jitter or the like, the content data accumulated in the reproduction buffer is reproduced, so that the reproduction is not interrupted. The larger the size of content data stored in the playback buffer, the greater the delay in packet arrival. That is, resistance to jitter is increased.

  Here, Patent Document 1 is a document in which video distribution is performed using a streaming technique. When distributing video to users using streaming technology, if the network between the distribution server and the client is congested, sufficient network transmission bandwidth for distributing high-quality video cannot be obtained, and video data is lost. Sometimes. If video data is missing, the encoded video cannot be decoded correctly, block noise will occur in the playback video, or the video will freeze, and the subjective video quality experienced by the user will deteriorate. .

  In Patent Document 1, in order to suppress the deterioration of the subjective video quality of the user, an encoded video of multi-stage quality is created, and an image with an optimal encoding speed is displayed according to the available network transmission band. There is a description of distribution. Specifically, the client has received an amount of data (packet loss amount) that could not be accurately received from the distribution server, temporal fluctuation of data arrival (delay fluctuation), or pre-reproduction data that has reached the client. Information such as the amount (buffering amount) is transmitted to the distribution server. The distribution server estimates the degree of network congestion based on information received from the client. When the network is congested, the distribution server reduces the transmission band of the video distributed to the user by one step.

  Patent Document 2 is a document in which a client including a reproduction buffer is described. In Patent Document 2, if a predetermined buffer amount cannot be secured even after buffering for a certain period of time, the client starts playback of content at a lower playback speed. By slowing down the reproduction speed, the reproduction time of the data stored in the reproduction buffer is lengthened, and the amount of data per unit time leaving the reproduction buffer is reduced. By buffering the content received from the distribution server in the meantime, tolerance against jitter can be increased.

JP 2007-194893 (paragraphs 0003 to 0005) JP 2008-92584 A

  The network between the distribution server and the client is often an open network such as the Internet. In an open network, the communication bandwidth that can be used between the distribution server and the client is limited due to the influence of cross traffic, etc., and it is difficult to transmit large data in a short time from the distribution server to the client. is there. Therefore, in order to increase the tolerance against jitter, it is preferable to increase the amount of content data buffered in the reproduction buffer.

  However, if the amount of content data buffered in the playback buffer is increased, the time for buffering data in the playback buffer becomes longer. While data is stored in the playback buffer before starting playback, the content is not played back, and this time is a waiting time for the user. Therefore, if the size of the content data buffered in the reproduction buffer is increased in order to increase the tolerance against jitter, the user's waiting time becomes longer. When this waiting time becomes longer, the satisfaction level of the user's service and the user's quality of experience decrease.

  Japanese Patent Application Laid-Open No. 2004-151561 is to reduce the video transmission band by one step when the network is congested. Patent Document 1 does not consider the influence of the time required to start the content reproduction on the user's sensation quality when determining the video transmission speed. Japanese Patent Laid-Open No. 2004-228561 increases the tolerance to jitter by slowing the reproduction speed. Similarly to Patent Document 1, Patent Document 2 does not determine content distribution parameters in consideration of the effect of buffering time on the user's quality of experience. In addition, in Patent Document 2, there is a problem that the sound pitch changes by slowing the reproduction speed, which gives the user a sense of incongruity or makes it difficult to hear the sound. Therefore, with the system described in Patent Document 2, the user's quality of experience cannot be kept high.

  The present invention provides a content distribution system, server, method, and program capable of solving the above-described problems of the prior art and suppressing a decrease in the quality of user experience in content distribution in which content reproduction is performed using a reproduction buffer. The purpose is to provide.

  In addition, the present invention provides a delivery parameter determination apparatus, method, and program capable of determining a delivery parameter that can suppress a decrease in the user's experience quality in content delivery that performs content playback using a playback buffer. With the goal.

  The present invention provides a sensation quality estimation device, a method, and a qualitative quality estimation device capable of performing quality evaluation in consideration of an effect on a user's sensation quality when content data is buffered in the reproduction buffer when content reproduction is performed using the reproduction buffer, and The purpose is to provide a program.

  In order to achieve the above object, the present invention reads content data from content storage means for storing content data of a plurality of distribution parameters, and has a playback buffer for the read content data, and the initial buffer is stored in the playback buffer. When content data for a time is buffered, a content distribution means for transmitting the content data to a client that starts playback of the content data via a network, and content data for the initial buffer time is stored in the playback buffer at the client. Referring to content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence of the buffering time indicating the time required for buffering on the subjective experience quality of the user, Buffering time and content Integrated experience quality estimation means for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of content data delivery based on data delivery parameters and network quality information of the network; Content distribution comprising: distribution parameter determining means for determining a distribution parameter of content data transmitted by the content distribution means from among the plurality of selectable distribution parameters based on the integrated experience quality estimated by the integrated experience quality estimation means Provide a system.

  The present invention is a content distribution method that uses a computer, has a reproduction buffer, and distributes content data to a client that starts reproduction of the content data when content data for an initial buffer time is buffered in the reproduction buffer. Considering the influence of the buffering time, which indicates the time required for the computer to buffer the content data for the initial buffer time in the playback buffer at the client, on the subjective quality of experience of the user The content quality evaluation information storage means for storing information for estimating the integrated quality of experience, the buffering time, the distribution parameter of the content data, and the network quality information of the network constituting the distribution route of the content data; Based on Based on the integrated experience quality estimation step that estimates the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of delivery of the tents data, and the computer estimates the integrated experience quality in the integrated experience quality estimation step A distribution parameter determining step for determining a distribution parameter of content data to be transmitted to the client from the plurality of selectable distribution parameters, and a content storage unit in which the computer stores content data of the plurality of distribution parameters. A content distribution method comprising: a content distribution step of reading content data of the distribution parameter determined in the distribution parameter determination step and transmitting the read content data to the client via the network Subjected to.

  The present invention has a computer having a playback buffer, and when content data for an initial buffer time is buffered in the playback buffer, a program for executing a process of distributing content data to a client that starts playback of the content data The buffering time indicating the time required for the content buffer for the initial buffer time to be buffered in the playback buffer at the client is affected by the computer on the subjective quality of experience of the user. The network quality information of the network that constitutes the buffering time, the content data distribution parameter, and the content data distribution route with reference to the content quality evaluation information storage means for storing information for estimating the integrated quality of experience And based on The integrated experience quality process for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of content data delivery, and the selection based on the integrated experience quality estimated by the integrated experience quality estimation process From the plurality of possible distribution parameters, the distribution parameter determination process for determining the distribution parameter of the content data to be transmitted to the client, and the content storage means for storing the content data of the plurality of distribution parameters, the distribution parameter determination process There is provided a program for reading content data of a determined distribution parameter and executing content distribution processing for transmitting the read content data to the client via the network.

  The present invention has a playback buffer, and when the content data for the initial buffer time is buffered in the playback buffer, the content for the initial buffer time is stored in the playback buffer at the client that starts playback of the content data. Refer to the content quality evaluation information storage means for storing information for estimating the integrated experience quality considering the influence of the buffering time indicating the time required for the data to be buffered on the subjective experience quality of the user. A plurality of distribution parameters that can be selected as distribution parameters at the time of content data distribution based on the buffering time, the content data distribution parameter, and the network quality information of the network that constitutes the content data distribution path. Integration to estimate the integrated experience quality Delivery parameter determination for determining a delivery parameter of content data to be transmitted to the client from among the plurality of selectable delivery parameters based on the sense of quality estimation means and the integrated experience quality estimated by the integrated experience quality estimation means And a delivery parameter determination device.

  The present invention uses a computer, has a reproduction buffer, and when the content data for the initial buffer time is buffered in the reproduction buffer, the distribution parameter for distributing the content data to the client that starts reproduction of the content data A buffering time indicating a time required for the computer to buffer content data for the initial buffer time in the playback buffer at the client. The content quality evaluation information storage means for storing information for estimating the integrated quality of experience in consideration of the influence on the quality is referred to, and the buffering time, the content data distribution parameter, and the content data distribution path are configured Network quality information of the network An integrated experience quality estimation step for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of content data delivery, and an integration estimated by the computer in the integrated experience quality estimation step There is provided a distribution parameter determination method including a distribution parameter determination step of determining a distribution parameter of content data to be transmitted to the client from among the plurality of selectable distribution parameters based on the quality of experience.

  The present invention provides a distribution parameter for distributing content data to a client that has a reproduction buffer in the computer and content data for an initial buffer time is buffered in the reproduction buffer and that starts reproduction of the content data. A program for executing a determining process, wherein the computer has a buffering time indicating a time required for the client to buffer content data for the initial buffer time in the playback buffer. The content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence on the overall experience quality is referred to, the buffering time, the content data delivery parameter, and the content data delivery route Network network Based on the network quality information, the integrated experience quality estimation process for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of content data delivery, and the integrated experience quality estimation process There is provided a program for executing a distribution parameter determination process for determining a distribution parameter of content data to be transmitted to the client from among the plurality of selectable distribution parameters based on an integrated quality of experience.

  The present invention has a playback buffer, and when the content data for the initial buffer time is buffered in the playback buffer, the content for the initial buffer time is stored in the playback buffer at the client that starts playback of the content data. Refer to the content quality evaluation information storage means for storing information for estimating the integrated experience quality considering the influence of the buffering time indicating the time required for the data to be buffered on the subjective experience quality of the user. A bodily sensation quality estimation device comprising: integrated bodily sensation quality estimation means for estimating the integrated bodily sensation quality based on the buffering time, content data distribution parameters, and network quality information of a network constituting the content data distribution path I will provide a.

  The present invention uses a computer, has a playback buffer, and when content data for an initial buffer time is buffered in the playback buffer, the content data of the user when the content data is delivered to the client that starts playback of the content data A method for estimating quality of experience, wherein the computer has a buffering time indicating a time required for buffering content data for the initial buffer time in the playback buffer at the client. The content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence on the quality of experience, and the buffering time, the delivery parameter of the content data, and the delivery route of the content data Network quality information of the configured network Based on the bets, it provides a QoE estimation method with integrated sensory quality estimation step of estimating the integrated quality of experience.

  The present invention has a playback buffer in a computer, and when content data for an initial buffer time is buffered in the playback buffer, the user experience when the content data is distributed to a client that starts playback of the content data. A program for executing a process for estimating quality, wherein a buffering time indicating a time required for the content data for the initial buffer time to be buffered in the reproduction buffer at the client is displayed on the computer. The content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence on the subjective experience quality of the content, the buffering time, the delivery parameter of the content data, the content data Of the networks that make up the delivery route Ttowaku based on the quality information and provides a program for executing the integrated experience quality estimation process for estimating the integrated quality of experience.

  The content distribution system, server, method, and program according to the present invention can distribute content in which content quality is reduced by using a reproduction buffer, while suppressing a decrease in the user's quality of experience.

  The distribution parameter determination apparatus, method, and program of the present invention can determine a distribution parameter that can suppress a decrease in the user's quality of experience in content distribution in which content reproduction is performed using a reproduction buffer.

  The experience quality estimation apparatus, method, and program according to the present invention provide a quality that takes into account the influence of the time that content data is buffered in the reproduction buffer has on the quality of experience of the user when content reproduction is performed using the reproduction buffer. Can be evaluated.

The block diagram which shows the content delivery system of 1st Embodiment of this invention. The block diagram which shows an integrated experience quality estimation means. The plot figure which shows the relationship between the integrated experience quality obtained by the subjective evaluation experiment, and an integrated experience quality estimated value. The flowchart which shows an operation | movement procedure. The distribution map which shows the relationship between a delivery parameter, buffering time, and integrated experience quality. The block diagram which shows the delivery system of the 1st modification of this invention. The block diagram which shows the delivery system of the 2nd modification of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a content distribution system according to a first embodiment of the present invention. The content distribution system includes a distribution server 100. The distribution server 100 includes a distribution parameter determination unit 101, a content distribution unit 102, a content quality evaluation information storage unit 103, a content information storage unit 104, a content file storage unit 105, and an integrated experience quality estimation unit 106. The function of each means in the distribution server 100 can be realized by a computer operating according to a predetermined program. The content quality evaluation information storage unit 103, the content information storage unit 104, and the content file storage unit 105 are storage devices such as hard disk drives.

  Distribution server 100 is connected to client 300 via network 200. The client 300 is, for example, a personal computer used by a user or a portable communication device. The client 300 includes a reproduction buffer 301 and an initial buffer time acquisition unit 302. The reproduction buffer 301 buffers content data distributed from the distribution server 100 during content reproduction.

  At the start of playback and during seek, the client 300 starts playback of content when content data for a predetermined time is buffered in the playback buffer 301. This predetermined time is determined by the specifications of the terminal. Or you may negotiate in advance between the client 300 and the delivery server 100, and may determine. This predetermined time is called initial buffer time. After starting the reproduction, the client 300 reproduces the content while buffering the content data in the reproduction buffer 301. The initial buffer time acquisition unit 302 acquires the initial buffer time and transmits it to the distribution server 100.

  The network 200 includes network quality measurement means 201. The network quality measuring unit 201 is constructed in, for example, a router that configures the network 200, a server device that monitors the network 200, and the like. The network quality measuring unit 201 monitors packets flowing through the network 200 and measures network quality information such as an available network bandwidth, a packet loss rate, and jitter. The network quality measuring unit 201 transmits the measured network quality information to the distribution server 100. Note that TCP (Transmission Control Protocol) is assumed as a protocol used for content distribution.

  The content file storage unit 105 stores content files (content data). The content file storage unit 105 stores content files of a plurality of distribution parameters. The delivery parameter includes a bit rate. The content file storage unit 105 stores content data having a plurality of different bit rates. The content file storage unit 105 stores, for example, a content file with a bit rate of 1 (1 Mbps) and a content file with a bit rate of 2 (512 kbps) for the content A.

  The content information storage unit 104 is a database that stores information related to the content file stored in the content file storage unit 105. The content information storage unit 104 stores distribution parameters that can be selected during content distribution for the content stored in the content file storage unit 105. For example, when the content file storage unit 105 stores a bit rate 1 content file and a bit rate 2 content file for the content A, the content information storage unit 104 has distribution parameters that can be selected for the content A. The fact that the bit rate is 1 and the bit rate 2 is stored.

  The integrated experience quality estimation means 106 estimates the user experience quality in consideration of the influence of the time required until the data corresponding to the initial buffer time is buffered in the reproduction buffer 301. Hereinafter, the time required for data for the initial buffer time to be buffered in the reproduction buffer 301 is referred to as buffering time. Further, hereinafter, in order to distinguish the user experience quality considering the influence of the buffering time from the normal experience quality not considering the influence of the buffering time, it is referred to as an integrated experience quality.

The above buffering time varies depending on the delivery parameter, the network bandwidth, and the initial buffer time. For example, assume that the available network bandwidth is 1 Mbps, the bit rate for content distribution is 500 kbps, and the initial buffer time is 1 s. The client 300 starts playback when buffering 500 kbps content data for 1 s in the playback buffer 301. In other words, when the client 300 buffers 500 kbit content data in the playback buffer 301, the client 300 starts playback. If the time required to transmit the 500 kbit content data from the distribution server 100 to the client 300 is that the entire network bandwidth can be used,
500kbit / 1Mbps = 0.5s
It becomes. This 0.5 s corresponds to the buffering time.

When the bit rate is halved to 250 kbps, the client 300 starts playback when buffering 250 kbps content data in the playback buffer 301. In this case, the buffering time is
250 kbit / 1 Mbps = 0.25 s
It becomes. The buffering time corresponds to the waiting time of the user at the start of content playback or seek. Generally, the higher the bit rate of the content, the higher the quality of the content alone. However, when the bit rate is increased, the waiting time of the user at the start of content reproduction or seek is increased in exchange for the quality of the content alone.

  The content distribution unit 102 reads the content data from the content file storage unit 105 and transmits it to the client 300 via the network 200. The distribution parameter determination unit 101 receives the initial buffer time from the initial buffer time acquisition unit 302 and receives the network quality information from the network quality measurement unit 201. The distribution parameter determination unit 101 acquires distribution parameters (parameter patterns) that can be selected from the content information storage unit 104 as distribution parameters of the content file distributed by the content distribution unit 102.

  The distribution parameter determination unit 101 calculates a buffering time when content distribution is performed with each distribution parameter based on the acquired distribution parameter, initial buffer time, and network quality information. The delivery parameter determination unit 101 passes the delivery parameter, buffering time, and network quality information to the integrated experience quality estimation unit 106, and for each of a plurality of delivery parameters that can be selected at the time of content delivery, Request an estimate.

  The content quality evaluation information storage means 103 is a database that stores information used when the integrated experience quality estimation means 106 estimates the integrated experience quality. The integrated experience quality estimation unit 106 refers to the content quality evaluation information storage unit 103, and estimates the integrated experience quality based on the delivery parameter, the buffering time, and the network quality information. The integrated experience quality estimation unit 106 estimates the integrated experience quality for each of the plurality of distribution parameters received from the distribution parameter determination unit 101.

  The integrated experience quality estimation unit 106 returns the estimated integrated experience quality to the delivery parameter determination unit 101. The distribution parameter determination unit 101 determines a distribution parameter used for content distribution from a plurality of selectable distribution parameters based on the integrated experience quality estimated by the integrated experience quality estimation unit 106. The content distribution unit 102 reads the content file of the distribution parameter determined by the distribution parameter determination unit 101 from the content file storage unit 105 and transmits it to the client 300 via the network 200.

  FIG. 2 shows the integrated experience quality estimation means 106. The integrated experience quality estimation unit 106 includes a content experience quality estimation unit 601 and an integrated experience quality estimation unit 602. The integrated experience quality estimation unit 106 receives the delivery parameter, network quality information, and buffering time from the delivery parameter determination unit 101. The content experience quality estimation unit 601 estimates the user experience quality based on the content distribution parameter and the network quality information. For the experience quality estimation performed by the content experience quality estimation unit 601, ITU-T Recommendation G. An algorithm such as 1070 can be used.

  As content, for example, video (moving image) content with sound is assumed. Content distribution parameters include video parameters and audio parameters. Video parameters include content encoding bit rate, resolution, and the like. The audio parameters include the audio encoding bit rate and sampling frequency of the content. The content is not limited to moving image content with audio, and may be content with only audio or video content without audio, and is arbitrary.

  The content quality evaluation information storage means 103 stores information for obtaining the quality of experience (content quality of experience) that does not consider the influence of the buffering time on the subjective quality of experience of the user from the distribution parameters and the network quality information. is doing. The content quality evaluation information storage unit 103 stores, for example, calculation formulas and calculation parameters necessary for obtaining content experience quality from distribution parameters and network quality. Alternatively, the content quality evaluation information storage unit 103 stores the correspondence between the combination of the distribution parameter and the network quality information and the content experience quality. The content experience quality to be stored may be an actual measurement value of a subjective experiment, or a value calculated using a model formula. The content experience quality estimation unit 601 refers to the content quality evaluation information storage unit 103 and obtains an estimate value of the content experience quality from the content distribution parameter and the network quality information.

  The integrated experience quality estimation unit 602 estimates the integrated experience quality based on the estimated value of the content experience quality estimated by the content experience quality estimation unit 601 and the buffering time. When estimating the integrated experience quality, the integrated experience quality estimation unit 602 obtains the degree of influence of the buffering time on the user's experience quality based on the buffering time. The integrated experience quality estimation unit 602 estimates the integrated experience quality from the obtained degree of influence and the content experience quality estimated by the content experience quality estimation unit 601.

  In addition to the above information, the content quality evaluation information storage means 103 stores information necessary for calculating the degree of influence that the buffering time has on the integrated quality of experience. The content quality evaluation information storage unit 103 stores, for example, calculation formulas and calculation parameters for calculating the degree of influence described above. The integrated experience quality estimation unit 602 refers to the content quality evaluation information storage unit 103 and obtains the degree of influence from the buffering time. The integrated experience quality estimation unit 602 sets the product of the obtained degree of influence and the estimated value of the content experience quality as the estimated value of the integrated experience quality.

  In order to examine the influence of the buffering time on the user's quality of experience, the present inventor sets a plurality of experimental conditions with different audio parameters, video parameters, and buffering times of the contents, and ITU- T recommendation Subjective evaluation experiment based on 911 was conducted. In the subjective evaluation experiment, assuming the Video On Demand service, the viewers watched the content, and the content quality of the content was evaluated for each experimental condition. The evaluation was performed in two ways: an evaluation when the influence of the buffering time was considered and an evaluation when the influence of the buffering time was not taken into consideration.

  The evaluation scale was classified into five levels: “very satisfied”, “satisfied”, “normal”, “dissatisfied”, “very dissatisfied”. The evaluation points were “very satisfied” 4 points, “satisfied” 3 points, “normal” 2 points, “dissatisfied” 1 point, and “very dissatisfied” 0 point. Subjective evaluation experiments were performed, and an average opinion score MOS (Mean Opinion Score: average value of the votes voted by the evaluator) was obtained for cases where the influence of buffering time was not taken into consideration.

  After the subjective evaluation experiment, the integrated quality of experience (MOSt) when considering the influence of the buffering time obtained in the subjective evaluation experiment, the content quality of experience (MOSc) not considering the influence of the buffering time, and the buffering time The relationship with (Tb) was formulated. In the formulation, the integrated sensory quality MOSt is an objective variable, the sensory quality MOSc and the buffering time Tb are explanatory variables, and the function MOSt = (c1 × ln (Tb) + c2) × MOSc considering each interaction is weighted. Regression analysis was performed to determine the values of constants c1 and c2.

  FIG. 3 shows the relationship between the integrated experience quality obtained in the subjective evaluation experiment and the integrated experience quality estimated value estimated using the above function. The subjects of the subjective evaluation experiment are a total of 7 men and women who use the Internet. The vertical axis represents the integrated experience quality MOSt obtained in the subjective experiment. The horizontal axis represents the integrated experience quality estimation value (MOSt ′) obtained by MOSt = (c1 × ln (Tb) + c2) × MOSc. Referring to FIG. 3, most of the data is located on a 45 degree line in the graph of FIG. From this, it can be seen that the above estimation formula accurately estimates the integrated quality of experience.

  FIG. 4 shows an operation procedure at the time of content distribution. The user requests the client 300 to start content reproduction or seek. The client 300 transmits a content distribution request to the distribution server 100 when the user performs processing such as start of reproduction of content or seek (step S1). The initial buffer time acquisition unit 302 acquires the initial buffer time and transmits it to the distribution parameter determination unit 101 (step S2). If the distribution server 100 knows the initial buffer time in advance, step S2 can be omitted. For example, when the initial buffer time is a predetermined fixed value, or when the initial buffer time is determined by performing negotiation in advance between the client 300 and the distribution server 100, step S2 may be omitted. .

  The network quality measuring unit 201 acquires network quality information such as an available network bandwidth, packet loss rate, and jitter of the network 200, and transmits it to the distribution parameter determining unit 101 (step S3). As a means for the network quality measuring means 201 to acquire network quality information from the network 200, a SNMP (Simple Network Management Protocol) mechanism can be used. Note that the timing at which the network quality measuring unit 201 acquires the network quality information is not particularly limited. The network quality measurement unit 201 may periodically acquire network quality information and periodically transmit the network quality information to the distribution server 100.

  Upon receiving the content distribution request from the client 300, the content distribution unit 102 requests the distribution parameter determination unit 101 to determine the distribution parameter. The distribution parameter determination unit 101 acquires a plurality of distribution parameters prepared for the content requested for distribution from the content information storage unit 104 (step S4). The distribution parameter determination unit 101 obtains a buffering time corresponding to each of the acquired plurality of distribution parameters from the initial buffer time, the network quality information, and the distribution parameters. The distribution parameter determination unit 101 passes the acquired plurality of distribution parameters, buffering time, and network quality information to the integrated experience quality estimation unit 106 and requests estimation of the integrated experience quality. If only one distribution parameter can be selected, the distribution parameter may be used as a content distribution parameter.

  The integrated experience quality estimation unit 106 acquires information necessary for calculating an estimated value of the integrated experience quality from the content quality evaluation information storage unit 103 (step S5). Based on the buffering time, the network quality information, and the distribution parameters, the integrated experience quality estimation unit 106 calculates an estimated value of the integrated experience quality for each of the plurality of distribution parameters received from the distribution parameter determination unit 101. Calculate (step S6). In the estimation of the integrated experience quality, the integrated experience quality estimation means 106 first obtains the content experience quality from the distribution parameters and the network quality information. Next, the integrated experience quality estimation means 106 uses (c × ln (Tb) + c2), where the buffering time is Tb, to determine the degree of influence that the buffering time has on the user experience quality. Thereafter, the integrated experience quality estimation unit 106 sets the product of the obtained content experience quality and the degree of influence as an estimated value of the integrated experience quality.

  The delivery parameter determination unit 101 determines a delivery parameter having the highest integrated experience quality estimation value calculated by the integrated experience quality estimation unit 106 as a delivery parameter used for content delivery among a plurality of delivery parameters that can be selected as delivery parameters. (Step S7). The distribution parameter determination unit 101 notifies the content distribution unit 102 of the determined distribution parameter. The content distribution unit 102 reads the content file of the distribution parameter determined by the distribution parameter determination unit 101 from the content file storage unit 105 and transmits it to the client 300 via the network 200 (step S8).

  The client 300 buffers the content file transmitted by the distribution server 100 in the reproduction buffer 301 (step S9). When the content data for the initial buffer time is buffered in the playback buffer 301, the playback means (not shown) in the client 300 starts playback of the content from the top of the playback buffer 301 (step S10). Thereafter, the client 300 reads the buffered content from the playback buffer 301 while buffering the content file in the playback buffer 301, and continues playback.

  In the present embodiment, the integrated experience quality estimation means 106 obtains content experience quality that does not take buffering time into account from the delivery parameter and network quality information. Further, based on the buffering time, the degree of influence of the buffering time on the user's quality of experience is obtained. The integrated experience quality estimation means 106 estimates the integrated experience quality considering the influence of the buffering time on the user experience quality from the content experience quality and the degree of influence. The distribution parameter determination unit 101 determines a distribution parameter that provides the best integrated experience quality as a distribution parameter of the content to be distributed among a plurality of distribution parameters that can be selected during content distribution. The content distribution unit 102 transmits the content data of the distribution parameter determined by the distribution parameter determination unit 101 to the client 300.

  When the playback buffer 301 is used to improve the tolerance against jitter, the client 300 does not start playback until content corresponding to the initial buffer time is buffered in the playback buffer 301, and this time (buffering time) , It was a waiting time for the user. However, until now, the influence of this waiting time on the user's quality of experience has not been considered. If the delivery parameters are determined based on the quality of the content itself while ignoring the buffering time, the waiting time of the user becomes longer, resulting in a decrease in the quality of the user's experience.

  In this embodiment, the user's bodily sensation quality is estimated including the influence of the buffering time, and the distribution parameter for content distribution is determined based on the estimated bodily sensation quality. In this way, even when the reproduction buffer 301 is used in order to increase the tolerance to jitter, it is possible to suppress a decrease in the user's quality of experience due to the buffering time. In other words, it is possible to distribute content that secures tolerance against jitter while reducing the user's uncomfortable feeling.

  Note that the magnitude of the influence of the buffering time on the quality of experience of the user varies depending on the scene in which the service is used. Specifically, even when the same content is played using a personal computer at home and when played using a portable communication device while moving, the buffering time is given to the user's quality of experience. The magnitude of the impact is different. In addition, the magnitude of the influence of the buffering time on the user's quality of experience varies depending on the genre of the content that the user reproduces. For example, in a content such as a news program, since the user wants to obtain information earlier, the shortness of the buffering time is more important than the quality of the video, and the influence of the buffering time on the quality of experience is large. On the other hand, in the case of content such as a movie, the cleanliness of video tends to be more important than the buffering time, and the influence of the buffering time on the quality of experience is small.

  In order to respond to the fact that the above-mentioned influence of the buffering time on the user experience quality varies depending on the service use scene and the content genre, the integrated experience quality estimation means uses the service use scene and content You may comprise so that the integrated experience quality according to a genre may be estimated. In order to make it possible to estimate the integrated experience quality according to the service usage scene and the content genre, the constants c1 and c2 included in the calculation formula of the integrated experience quality estimation value are obtained for each assumed service usage scene and genre. deep. The values of the constants c1 and c2 can be obtained by performing a subjective evaluation experiment on a plurality of service usage scenes and content genres. The obtained constants c1 and c2 are stored in the content quality evaluation information storage means 103 in association with service usage scenes and content genres.

  At the time of content distribution, the distribution parameter determination unit 101 notifies the integrated experience quality estimation unit 106 of information such as the service usage scene of the user and the genre of the content to be reproduced. The integrated experience quality estimation unit 106 reads the service usage scene notified from the distribution parameter determination unit 101 and the values of constants c1 and c2 corresponding to the content genre from the content evaluation information storage 103. The integrated experience quality estimation means 106 may apply the read constants c1 and c2 to a calculation formula for estimating the integrated experience quality, and estimate the integrated experience quality according to the service usage scene and the content genre.

  Subsequently, a second embodiment of the present invention will be described. The configuration of the distribution system according to the second embodiment of the present invention is the same as the configuration according to the first embodiment shown in FIG. In the first embodiment, the integrated experience quality is obtained from the content experience quality that does not consider the influence of the buffering time on the user experience quality and the degree of influence that the buffering time has on the user experience quality. In the present embodiment, the content quality evaluation information storage unit 103 stores information for obtaining the integrated experience quality from the buffering time and the delivery parameter. The integrated experience quality estimation means 106 refers to the information and estimates the integrated experience quality.

  FIG. 5 shows the relationship among distribution parameters (bit rate Br), buffering time (Tb), and integrated quality of experience (MOSt). The integrated sensory quality MOSt in FIG. 5 is an actually measured value of the integrated sensory quality obtained in the subjective evaluation experiment or an estimated value of the integrated sensory quality obtained by the model formula (MOSt = (c1 × ln (Tb) + c2) × MOSc). It is. In the content quality evaluation information storage means 103, a relationship as shown in the distribution chart of FIG. 5 is stored in advance.

If the network bandwidth is R, the relationship between bandwidth R, bit rate Br, buffering time Tb, and initial buffer time b0 is:
R × Tb = Br × b0
It can be expressed as. The initial buffer time b0 and the network use bandwidth R are values determined from the initial buffer time acquired by the initial buffer time acquisition unit 302 and the network quality information measured by the network quality measurement unit 201, respectively. If the above equation is modified, the relationship between the bit rate Br and the buffering time Tb can be expressed as Br = (R / b0) × Tb.

  The above relational expression corresponds to a straight line on the bottom surface in the distribution diagram of FIG. In the distribution diagram of FIG. 5, an intersection line between a surface passing through this straight line and perpendicular to the bottom surface and a curve representing the integrated quality of experience is obtained. In the intersection line, the bit rate at which the integrated experience quality MOSt is maximized represents the bit rate at which the user experience quality is the best in the current environment (usage bandwidth, initial buffer time). The distribution parameter determination unit 101 may determine this bit rate as a parameter used for content distribution.

  Actually, delivery parameters that can be selected as content delivery parameters are determined in advance. The distribution parameter determination unit 101 performs the following processing to obtain a distribution parameter (bit rate) that maximizes the integrated quality of experience MOSt at the intersection line. The distribution parameter determination unit 101 first acquires a plurality of selectable distribution parameters (bit rate Br) from the content information storage unit 104. Next, the delivery parameter determination unit 101 obtains the buffering time Tb from the bit rate Br, the network available bandwidth R, and the initial buffer time b0. The delivery parameter determination unit 101 passes a set of a plurality of selectable bit rates Br and a buffering time Tb corresponding to the bit rate Br to the integrated experience quality estimation unit 106.

  The integrated experience quality estimation means 106 refers to the content quality evaluation information storage means 103, and from the distribution diagram shown in FIG. 5, the integrated experience quality estimation means 106 corresponds to the combination of the bit rate Br and the buffering time Tb received from the distribution parameter determination means 101. Find the quality MOSt. The integrated experience quality estimation unit 106 obtains an integrated experience quality MOSt for a set of a plurality of bit rates Br and buffering time received from the distribution parameter determination unit 101. The integrated experience quality estimation unit 106 returns the value of the integrated experience quality MOSt to the distribution parameter determination unit 101. Distribution parameter determining means 101 determines the bit rate at which the value of integrated experience quality MOSt obtained by integrated experience quality estimation means 106 is maximized as a parameter used for content distribution.

  In the present embodiment, the content quality evaluation information storage unit 103 stores information for estimating the integrated experience quality from the distribution parameter and the buffering time. The integrated experience quality estimation unit 106 refers to the content quality evaluation information storage unit 103 and estimates the integrated experience quality from the distribution parameter and the buffering time. The distribution parameter determination unit 101 determines a distribution parameter that provides the best integrated experience quality estimated by the integrated experience quality estimation unit 106 as a parameter used for content distribution. Even in such a configuration, as in the first embodiment, it is possible to obtain an effect that content distribution with reduced tolerance to jitter can be achieved while reducing the user's uncomfortable feeling.

  In each of the above embodiments, the distribution parameter determination unit 101 determines the buffering time from the distribution parameter, the network quality information, and the initial buffer time. However, the unit for determining the buffering time is limited to the distribution parameter determination unit 101. Not. For example, the delivery parameter, the network quality information, and the initial buffer time may be given to the integrated experience quality estimation unit 106, and the integrated experience quality estimation unit 106 may obtain the buffering time. Alternatively, a means for obtaining the buffering time and providing it to the integrated experience quality estimation means 106 may be provided outside the distribution parameter determination means 101 or the integrated experience quality estimation means 106.

  In FIG. 1, the network quality measuring unit 201 is attached to the network 200, but is not limited thereto. A configuration in which the network quality measuring unit is provided in the distribution server 100 or a configuration in which the network quality measuring unit is provided in the client 300 is also possible. 6 and 7 show distribution systems of first and second modifications, respectively. FIG. 6 shows a configuration in which network quality measuring means 107 is provided in the distribution server 100. The network quality measuring unit 107 measures the transmission speed of the packet to be transmitted to the client 300 and estimates the usable bandwidth of the network 200. The distribution parameter determination unit 101 receives information on the available bandwidth from the network quality measurement unit 107.

  FIG. 7 shows a configuration in which network quality measuring means 303 is provided in the client 300. The network quality measuring unit 303 measures the reception speed of packets received from the distribution server 100 and estimates the available bandwidth of the network 200. The network quality measuring unit 303 transmits the estimated usable bandwidth information to the distribution server 100. For example, when the network quality measuring unit 303 requests content from the distribution server 100, the network quality measurement unit 303 estimates the available bandwidth and transmits the estimated bandwidth to the distribution server 100. The timing at which the network quality measuring unit 303 transmits information on the available bandwidth is arbitrary and is not particularly limited.

  In each of the above embodiments, TCP is assumed as a protocol used for content distribution, but the protocol is not limited to TCP. For example, UDP (User Data Protocol) can be used for content distribution. When UDP is used for content distribution, FEC (Forward Error Correction) redundancy can be included in the distribution parameter. When finding the quality of experience without taking buffering time into consideration, the quality of experience of the content including the packet loss rate is obtained as a video quality parameter. When content is transmitted with the FEC redundancy increased, the packet loss rate when data is restored is apparently lower than the actual packet loss rate that occurred in the network. However, in the case of the same transmission rate, if redundancy using FEC is performed, the bit rate of the content that can be transmitted becomes lower than in the case where it is not performed.

  An experiment is performed in advance to determine how many percent of the packet loss rate can be reduced by setting the redundancy, and the correspondence between the two is stored in the content quality evaluation information storage unit 103. The integrated experience quality estimation means 106 inputs a model expression together with an apparent packet loss rate when FEC is applied to a plurality of selectable bit rates, and estimates the integrated experience quality. The distribution parameter determination unit 101 may determine the bit rate and the FEC redundancy that provide the best integrated experience quality as distribution parameters.

  Although the present invention has been described based on the preferred embodiment, the content distribution system, distribution parameter determination device, quality estimation device, method, and program of the present invention are not limited to the above embodiment. Rather, various modifications and changes made from the configuration of the above embodiment are also included in the scope of the present invention.

  The minimum configuration of the present invention will be described below. The content distribution system of the present invention includes, as a minimum configuration, a content distribution unit, an integrated experience quality estimation unit, and a distribution parameter determination unit. The content distribution unit reads the content data from the content storage unit and transmits it to the client via the network. The content storage means stores content data of a plurality of distribution parameters. The client that receives the content data has a playback buffer, and starts playback when the content data of the initial buffer time portion is buffered in the playback buffer. The integrated experience quality estimation means refers to the content quality evaluation information storage means, and can be selected as a delivery parameter at the time of content data delivery based on the buffering time, the content data delivery parameter, and the network quality information of the network. Estimate integrated experience quality for multiple delivery parameters. The buffering time is the time required for the content data for the initial buffer time to be buffered in the playback buffer at the client. The integrated sensory quality is a sensory quality that takes into account the effect of buffering time on the subjective sensory quality of the user. The distribution parameter determination unit determines a distribution parameter of content data transmitted by the content distribution unit from a plurality of selectable distribution parameters based on the estimated integrated experience quality.

  The minimum configuration of the content distribution method of the present invention is a method for distributing content data to a client that has a playback buffer and starts playback of content data when content data for the initial buffer time is buffered in the playback buffer. In addition, the integrated experience quality is estimated in consideration of the influence of the buffering time indicating the time required for buffering the content data for the initial buffer time in the playback buffer at the client on the subjective experience quality of the user. Content quality evaluation information storage means for storing information for content data distribution based on buffering time, content data distribution parameters, and network quality information of the network constituting the content data distribution path Selected as a delivery parameter for Based on the integrated experience quality estimation step that estimates the integrated experience quality for multiple possible delivery parameters, and the integrated experience quality estimated in the integrated experience quality estimation step, the client can select from a plurality of delivery parameters that can be selected. The content data of the distribution parameter determined in the distribution parameter determination step is read from the distribution parameter determination step of determining the distribution parameter of the content data to be transmitted and the content storage means for storing the content data of the plurality of distribution parameters, and the read content data And a content distribution step for transmitting to the client via the network.

  The minimum configuration of the program (content distribution program) of the present invention is that a computer has a reproduction buffer, and content data for an initial buffer time is buffered in the reproduction buffer. A program that executes a process of distributing data, and a buffering time indicating a time required for a client to buffer content data for an initial buffer time in a playback buffer at a client. Network that configures buffering time, content data distribution parameters, and content data distribution path with reference to content quality evaluation information storage means for storing information for estimating integrated quality of experience in consideration of the influence on quality Net Integrated experience quality processing that estimates the integrated experience quality for multiple delivery parameters that can be selected as delivery parameters at the time of content data delivery, and the integrated experience estimated by the integrated experience quality estimation process. From a plurality of selectable distribution parameters based on quality, a distribution parameter determination process for determining a distribution parameter of content data to be transmitted to the client, and a content storage means for storing content data of the plurality of distribution parameters. The content data of the distribution parameter determined in the parameter determination process is read out, and the content distribution process of transmitting the read content data to the client via the network is executed.

  In the content distribution system, method, and program of the present invention, the integrated quality of experience including the effect of buffering time is estimated for a plurality of selectable distribution parameters. Based on the estimated integrated quality of experience, the distribution parameter of the content distribution is determined, and the content data of the determined distribution parameter is transmitted to the client. As described above, by estimating the user's experience quality including the influence of the buffering time, it is possible to suppress a decrease in the user's experience quality in content distribution in which content reproduction is performed using the reproduction buffer.

  The minimum configuration of the distribution parameter determination apparatus of the present invention includes an integrated experience quality estimation unit and a distribution parameter determination unit. The integrated experience quality estimation means refers to the content quality evaluation information storage means, and can be selected as a delivery parameter at the time of content data delivery based on the buffering time, the content data delivery parameter, and the network quality information of the network. Estimate integrated experience quality for multiple delivery parameters. The client that distributes the content data has a reproduction buffer, and starts reproduction when the content data of the initial buffer time portion is buffered in the reproduction buffer. The buffering time is the time required for the content data for the initial buffer time to be buffered in the playback buffer at the client. The integrated sensory quality is a sensory quality that takes into account the effect of buffering time on the subjective sensory quality of the user. The distribution parameter determining means determines a distribution parameter of content data to be transmitted to the client from a plurality of selectable distribution parameters based on the estimated integrated quality of experience.

  The minimum configuration of the delivery parameter determination method of the present invention has a playback buffer, and when content data for the initial buffer time is buffered in the playback buffer, content data is delivered to a client that starts playback of the content data. The method of determining the distribution parameter of the client, and the influence of the buffering time on the subjective experience quality of the user indicating the time required for the content data for the initial buffer time to be buffered in the playback buffer at the client Referring to content quality evaluation information storage means for storing information for estimating the integrated quality of experience taking into account the network quality information of the network constituting the buffering time, the content data distribution parameter, and the content data distribution route Based on the content Integrated experience quality estimation step for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of distribution, and a plurality of selectable based on the integrated experience quality estimated in the integrated experience quality estimation step A distribution parameter determining step for determining a distribution parameter of content data to be transmitted to the client from among the distribution parameters.

  The minimum configuration of the program (distribution parameter determination program) of the present invention is a client having a playback buffer in the computer and starting playback of content data when content data for the initial buffer time is buffered in the playback buffer. A program for executing a process for determining a delivery parameter when delivering content data, a buffer indicating a time required for buffering content data for an initial buffer time in a playback buffer in a computer The content quality evaluation information storage means for storing information for estimating the integrated experience quality considering the influence of the ring time on the subjective experience quality of the user, the buffering time, the delivery parameter of the content data, Distribution of content data Integrated experience quality estimation process for estimating integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of content data delivery, based on network quality information of a network constituting the route, and an integrated experience quality estimation step The distribution parameter determination process for determining the distribution parameter of the content data to be transmitted to the client from the plurality of selectable distribution parameters is executed based on the integrated quality of experience estimated in (1).

  In the delivery parameter determination apparatus, method, and program of the present invention, the integrated quality of experience including the effect of buffering time is estimated for a plurality of selectable delivery parameters. A distribution parameter for content distribution is determined based on the estimated integrated quality of experience. In this way, by estimating the user's experience quality including the influence of the buffering time, the distribution parameters that can suppress the decrease in the user's experience quality in the content distribution that performs content reproduction using the reproduction buffer, It can be determined as a parameter for content distribution.

  The sensation quality estimation apparatus of the present invention includes an integrated sensation quality estimation means. The integrated experience quality estimation means refers to the content quality evaluation information storage means, and estimates the integrated experience quality based on the buffering time, the distribution parameter of the content data, and the network quality information of the network. The client that distributes the content data has a reproduction buffer, and starts reproduction when the content data of the initial buffer time portion is buffered in the reproduction buffer. The buffering time is the time required for the content data for the initial buffer time to be buffered in the playback buffer at the client. The integrated sensory quality is a sensory quality that takes into account the effect of buffering time on the subjective sensory quality of the user.

  The experience quality estimation method of the present invention has a playback buffer, and when content data for the initial buffer time is buffered in the playback buffer, the user's data when the content data is delivered to the client that starts playback of the content data is stored. This is a method for estimating the quality of experience, and the influence of the buffering time, which indicates the time required for the content data for the initial buffer time to be buffered in the playback buffer, on the user's subjective quality of experience. Referring to content quality evaluation information storage means for storing information for estimating the integrated quality of experience, buffering time, content data distribution parameters, and network quality information of the network constituting the content data distribution path; Integration to estimate the integrated experience quality based on With sensitive quality estimation step.

  The minimum configuration of the program (experience quality estimation program) of the present invention is a client having a reproduction buffer in the computer and starting reproduction of content data when content data for the initial buffer time is buffered in the reproduction buffer. A program for executing processing for estimating a user's quality of experience when content data is distributed, the time required for buffering content data for an initial buffer time in a playback buffer in a computer Referring to the content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence of the buffering time shown on the subjective experience quality of the user, and the buffering time and the delivery parameter of the content data And the distribution route of the content data Based on the network quality information of the network which constitutes a configuration that is running the integrated experience quality estimation processing for estimating an integrated quality of experience.

  In the experience quality estimation apparatus, method, and program of the present invention, the integrated experience quality including the influence of the buffering time is estimated for the delivery parameter. In the present invention, since the quality of experience including the influence of the buffering time is estimated, when content is reproduced using the reproduction buffer, the time that the content data is buffered in the reproduction buffer has an influence on the quality of experience of the user. It is possible to perform quality evaluation in consideration.

100: distribution server 101: distribution parameter determination unit 102: content distribution unit 103: content quality evaluation information storage unit 104: content information storage unit 105: content file storage unit 106: integrated experience quality estimation unit 107, 201, 303: network quality Measuring means 200: Network 300: Client 301: Playback buffer 302: Initial buffer time acquisition means 601: Content experience quality estimation unit 602: Integrated experience quality estimation unit

Claims (27)

When content data is read from content storage means for storing content data of a plurality of distribution parameters, the read content data has a playback buffer, and content data for an initial buffer time is buffered in the playback buffer Content distribution means for transmitting via a network to a client that starts reproduction of content data;
The integrated sensory quality is estimated in consideration of the influence of the buffering time indicating the time required for buffering the content data for the initial buffer time in the playback buffer at the client on the subjective sensory quality of the user. Can be selected as a distribution parameter at the time of content data distribution based on the buffering time, content data distribution parameter, and network quality information of the network Integrated experience quality estimation means for estimating the integrated experience quality for a plurality of delivery parameters;
Content provided with distribution parameter determination means for determining a distribution parameter of content data transmitted by the content distribution means from among the plurality of selectable distribution parameters based on the integrated experience quality estimated by the integrated experience quality estimation means Distribution system.   The distribution parameter determination unit acquires the plurality of selectable distribution parameters from a content information storage unit that stores a plurality of selectable distribution parameters for the content file stored in the content file storage unit, The content distribution system according to claim 1, wherein distribution parameters are passed to the integrated experience quality estimation unit to request estimation of integrated experience quality.   The content distribution system according to claim 1, further comprising network quality measuring means for acquiring network quality information of the network. The information stored in the content quality information storage means includes information for estimating the sensation quality without considering the influence of the buffering time on the subjective sensation quality of the user from the distribution parameter and the network quality information. And
The integrated experience quality estimation means,
A content experience quality estimation unit that refers to the content quality information storage unit and estimates the experience quality without considering the influence of the buffering time on the subjective experience quality of the user from the delivery parameter and the network quality information; ,
Based on the buffering time, the degree of influence of the buffering time on the user's bodily sensation quality is obtained, and the integrated bodily sensation quality is estimated based on the bodily sensation quality estimated by the content bodily sensation quality estimation unit and the degree of influence. The content distribution system according to claim 1, further comprising an integrated experience quality estimation unit. The integrated sensation quality estimation unit sets the buffering time as Tb, c1 and c2 as constants,
c1 × ln (Tb) + c2
The content distribution system according to claim 4, wherein the value calculated in step S3 is the influence level.   The content according to claim 4 or 5, wherein the integrated experience quality estimation unit uses the product of the degree of influence and the estimate value of the experience quality estimated by the content experience quality estimation unit as the estimate value of the integrated experience quality. Distribution system.   The information stored in the content quality information storage means includes information for estimating the integrated experience quality from the buffering time and the delivery parameter, and the integrated experience quality estimation means stores the content quality information storage The content distribution system according to any one of claims 1 to 3, wherein the integrated quality of experience is estimated from the buffering time and the distribution parameter with reference to a means. When the content buffer for the initial buffer time is buffered in the playback buffer, the content data for the initial buffer time is buffered in the playback buffer at the client that starts playback of the content data. The content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence of the buffering time indicating the time required for the user experience on the subjective experience quality, and said buffering Based on the time, content data distribution parameters, and network quality information of the network that constitutes the content data distribution route, the integrated quality of experience for a plurality of distribution parameters that can be selected as distribution parameters at the time of content data distribution Integrated experience quality estimation And means,
A distribution parameter determining unit configured to determine a distribution parameter of content data to be transmitted to the client from the plurality of selectable distribution parameters based on the integrated sensory quality estimated by the integrated sensory quality estimation unit; Decision device.   When the content buffer for the initial buffer time is buffered in the playback buffer, the content data for the initial buffer time is buffered in the playback buffer at the client that starts playback of the content data. The content quality evaluation information storage means for storing information for estimating the integrated experience quality in consideration of the influence of the buffering time indicating the time required for the user experience on the subjective experience quality, and said buffering A sensation quality estimation apparatus comprising an integrated sensation quality estimation unit that estimates the integrated sensation quality based on time, content data distribution parameters, and network quality information of a network constituting a content data distribution route. A content distribution method using a computer, having a playback buffer, and distributing content data to a client that starts playback of the content data when content data for an initial buffer time is buffered in the playback buffer,
An integrated experience in consideration of the influence of the buffering time on the subjective experience quality of the user indicating the time required for the computer to buffer the content data for the initial buffer time in the playback buffer at the client Refer to content quality evaluation information storage means for storing information for estimating quality, and based on the buffering time, content data distribution parameters, and network quality information of the network constituting the content data distribution path An integrated experience quality estimation step for estimating the integrated experience quality for a plurality of delivery parameters selectable as delivery parameters at the time of content data delivery;
A distribution parameter determining step in which the computer determines a distribution parameter of content data to be transmitted to the client from the plurality of selectable distribution parameters based on the integrated experience quality estimated in the integrated experience quality estimation step; ,
The computer reads the content data of the distribution parameter determined in the distribution parameter determination step from the content storage means for storing the content data of a plurality of distribution parameters, and transmits the read content data to the client via the network And a content distribution method. Prior to the integrated quality of experience estimation step, the computer selects the plurality of selectable distributions from a content information storage unit that stores a plurality of distribution parameters that can be selected for the content file stored in the content file storage unit. The method further comprises a selectable delivery parameter acquisition step of acquiring a parameter,
The content distribution method according to claim 10, wherein in the integrated experience quality estimation step, the computer estimates an integrated experience quality with respect to the distribution parameter acquired in the selectable distribution parameter acquisition step.   The content distribution method according to claim 10 or 11, wherein the computer further includes a network quality measurement step of acquiring network quality information of the network prior to the integrated experience quality estimation step. The information stored in the content quality information storage means includes information for estimating the sensation quality without considering the influence of the buffering time on the subjective sensation quality of the user from the distribution parameter and the network quality information. And
The integrated experience quality estimation step comprises:
The computer refers to the content quality information storage unit, and estimates from the delivery parameter and the network quality information the experience quality that does not consider the influence of the buffering time on the subjective experience quality of the user; ,
Based on the buffering time, the computer obtains the degree of influence that the buffering time has on the user's bodily sensation quality, and based on the bodily sensation quality estimated in the content bodily sensation quality estimation step and the degree of influence, the integrated bodily sensation The content distribution method according to claim 10, further comprising a step of estimating quality. In the step of estimating the integrated quality of experience, the computer sets the buffering time as Tb, c1 and c2 as constants, and the following formula:
c1 × ln (Tb) + c2
The content distribution method according to claim 13, wherein the value calculated in step S3 is the influence degree.   In the step of estimating the integrated experience quality, the computer uses a product of the influence level and the estimated value of the experience quality estimated in the step of estimating the content experience quality as the estimated value of the integrated experience quality. Item 15. The content distribution method according to Item 13 or 14. The information stored in the content quality information storage means includes information for estimating the integrated experience quality from the buffering time and the delivery parameter,
13. In the integrated experience quality estimation step, the computer estimates the integrated experience quality from the buffering time and the delivery parameter with reference to the content quality information storage unit. The content distribution method described in 1. A method for determining a delivery parameter for delivering content data to a client having a playback buffer and having a playback buffer and content data for an initial buffer time is buffered in the playback buffer and starting playback of the content data Because
Integration in consideration of the influence of the buffering time on the subjective experience quality of the user, indicating the time required for the content buffer for the initial buffer time to be buffered in the playback buffer at the client Referencing content quality evaluation information storage means for storing information for estimating quality of experience, and based on the buffering time, content data distribution parameters, and network quality information of the network constituting the content data distribution path Integrated experience quality estimation step for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of content data delivery;
A distribution parameter determining step in which the computer determines a distribution parameter of content data to be transmitted to the client from the plurality of selectable distribution parameters based on the integrated experience quality estimated in the integrated experience quality estimation step; A delivery parameter determination method. Using a computer and having a playback buffer, when content data for the initial buffer time is buffered in the playback buffer, the user's quality of experience when the content data is distributed to the client that starts playback of the content data is estimated A way to
Integration in consideration of the influence of the buffering time on the subjective experience quality of the user, indicating the time required for the content buffer for the initial buffer time to be buffered in the playback buffer at the client Referencing content quality evaluation information storage means for storing information for estimating quality of experience, and based on the buffering time, content data distribution parameters, and network quality information of the network constituting the content data distribution path A bodily sensation quality estimation method comprising an integrated bodily sensation quality estimation step for estimating the integrated bodily sensation quality. The computer has a reproduction buffer, and when the content data for the initial buffer time is buffered in the reproduction buffer, the program executes a process of distributing the content data to a client that starts reproduction of the content data, In the computer,
The integrated sensory quality is estimated in consideration of the influence of the buffering time indicating the time required for buffering the content data for the initial buffer time in the playback buffer at the client on the subjective sensory quality of the user. Content data evaluation information storage means for storing information for content data distribution based on the buffering time, content data distribution parameters, and network quality information of a network constituting the content data distribution path Integrated experience quality processing for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time;
A distribution parameter determination process for determining a distribution parameter of content data to be transmitted to the client from the plurality of selectable distribution parameters based on the integrated experience quality estimated in the integrated experience quality estimation process;
Content distribution for reading content data of distribution parameters determined in the distribution parameter determination process from content storage means for storing content data of a plurality of distribution parameters, and transmitting the read content data to the client via the network A program that executes processing. Prior to the integrated quality of experience estimation process, a plurality of selectable distributions from content information storage means for storing a plurality of distribution parameters selectable for content files stored in the content file storage means in the computer. Further execute selectable delivery parameter acquisition processing for acquiring parameters,
The program according to claim 19, wherein in the integrated experience quality estimation process, an integrated experience quality is estimated for the delivery parameter acquired in the selectable delivery parameter acquisition process.   The program according to claim 19 or 20, further causing the computer to execute a network quality measurement process for acquiring network quality information of the network prior to the integrated experience quality estimation process. The information stored in the content quality information storage means includes information for estimating the sensation quality without considering the influence of the buffering time on the subjective sensation quality of the user from the distribution parameter and the network quality information. And
The integrated experience quality estimation process is
A process of referring to the content quality information storage means, and estimating the quality of experience without considering the influence of the buffering time on the subjective quality of experience of the user from the delivery parameter and the network quality information;
Based on the buffering time, the degree of influence that the buffering time has on the user's bodily sensation quality is obtained, and based on the bodily sensation quality estimated in the process of estimating the content bodily sensation quality and the degree of influence, the integrated bodily sensation quality The program according to any one of claims 19 to 21, further comprising: In the process of estimating the integrated quality of experience, the buffering time is Tb, and c1 and c2 are constants.
c1 × ln (Tb) + c2
The program according to claim 22, wherein the value calculated in step is used as the degree of influence.   23. In the process of estimating the integrated experience quality, a product of the influence level and the estimated value of the experience quality estimated in the process of estimating the content experience quality is set as the estimated value of the integrated experience quality. The program according to 23. The information stored in the content quality information storage means includes information for estimating the integrated experience quality from the buffering time and the delivery parameter,
The program according to any one of claims 19 to 21, wherein, in the integrated experience quality estimation process, the integrated experience quality is estimated from the buffering time and the delivery parameter with reference to the content quality information storage unit. . The computer has a playback buffer, and when content data for an initial buffer time is buffered in the playback buffer, a process for determining a delivery parameter for delivering the content data to a client that starts playback of the content data A program to be executed by the computer;
Estimating the integrated experience quality in consideration of the influence of the buffering time indicating the time required for buffering the content data for the initial buffer time on the playback buffer on the subjective experience quality of the user at the client The content quality evaluation information storage means for storing information to store the content data based on the buffering time, the distribution parameter of the content data, and the network quality information of the network constituting the distribution route of the content data An integrated experience quality estimation process for estimating the integrated experience quality for a plurality of delivery parameters that can be selected as delivery parameters at the time of delivery;
Based on the integrated experience quality estimated in the integrated experience quality estimation process, a delivery parameter determination process for determining a delivery parameter of content data to be transmitted to the client from the plurality of selectable delivery parameters is executed. program. The computer has a playback buffer, and when content data for the initial buffer time is buffered in the playback buffer, the user's quality of experience when the content data is distributed to the client that starts playback of the content data is estimated. A program for executing processing, wherein the computer
Estimating the integrated experience quality in consideration of the influence of the buffering time indicating the time required for buffering the content data for the initial buffer time on the playback buffer on the subjective experience quality of the user at the client Referring to content quality evaluation information storage means for storing information for performing the integration based on the buffering time, content data distribution parameters, and network quality information of a network constituting the content data distribution path A program that executes integrated experience quality estimation processing for estimating experience quality.

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