KR20170100079A - System and method for providing of cloud streaming service which is adapting to network environment - Google Patents

Abstract

The present invention relates to a cloud streaming system, in which a video quality to be transmitted to a user terminal is set in consideration of both a first network state between a video server and a cloud server and a second network state between a cloud server and a user terminal in a cloud server, And more particularly, to a network environment adaptive cloud streaming system and method for enhancing video playback quality on the screen.
The network environment adaptive cloud streaming system and method according to the present invention comprise video fragment information by quality for video contents, and a video stream including a video fragment of a predetermined quality according to a video download request from a cloud server A user terminal configured to perform a video content request to a cloud server, reproduce an image stream provided from the cloud server, and output the image stream to a screen, and a video server The method comprising: performing a video download request to the video server, converting the video stream received from the video server into an image stream to provide the video stream to the user terminal, Acquires the conversion rate calculated based on the off streaming throughput and the image streaming throughput in the user terminal and the image stream round trip time with the user terminal and sets the video quality higher as the conversion rate and the round trip time decrease, And a cloud server configured to provide video download request information including quality information to the video server.

Description

TECHNICAL FIELD The present invention relates to a system and method for providing adaptive cloud streaming service in a network environment,

The present invention relates to a cloud streaming system, in which a video quality to be transmitted to a user terminal is set in consideration of both a first network state between a video server and a cloud server and a second network state between a cloud server and a user terminal in a cloud server, And more particularly, to a network environment adaptive cloud streaming system and method for enhancing video playback quality on the screen.

With the development of the mobile communication network and the development of the terminal specification, the mobile communication terminal has become a necessity of the modern person beyond the scope of the conventional simple communication apparatus or information providing apparatus, and is evolving into a total entertainment apparatus.

In addition, in recent years, it is difficult for a low-performance client terminal to process a large-capacity image or the like. Therefore, it is necessary to process the corresponding data through a cloud server at a remote location, And a cloud computing technology for receiving and displaying data on a client terminal has been developed and utilized.

Particularly, in the cloud computing technology, a game, a VOD, a real-time broadcast content, and the like are executed on the server side, and the execution screen is transmitted to the user device in a streaming manner so that only the input and output are performed in the user device, It is being used as a cloud streaming service that allows users to use the desired content regardless of their specifications and performance.

The cloud streaming service executes a request input from the user device in the service device connected to the user device via the communication network, and transmits the result to the user device. At this time, the cloud latency service decreases the user satisfaction and the service quality as the latency for receiving and outputting the result after user request becomes longer. Here, the waiting time depends mostly on the state of the communication network formed between the service apparatus and the user apparatus.

Meanwhile, as the video contents are diversified, the system for the cloud streaming service is structured in such a manner that a server providing content and a cloud server are separated from each other. The cloud server converts a video stream provided from the content server into an image stream, The network state formed between the content server and the cloud server, and the network state between the cloud server and the user device are both related to the service quality displayed and outputted to the user device.

Accordingly, in order to improve the quality of service provided to the user equipment, it is necessary to set the video quality in consideration of all network conditions formed between the device providing the video content and the user equipment performing the screen playback process on the video content.

1. Korean Patent Laid-Open No. 10-2015-0102450 (entitled " Cloud Streaming Based Image Data Providing Method, Apparatus and System for the Same) 2. Korean Patent No. 10-1512241 entitled " Method and System for Providing Contents to a Digital Video Recorder Using Personal Virtualization Based on Clouds "

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method and system for providing a video streaming service in a cloud server, There is a technical purpose of providing a network environment adaptive cloud streaming system and a method thereof, which can improve video reproduction quality displayed on a screen through a user terminal by setting video quality based on an image stream round-trip time.

According to an aspect of the present invention, there is provided a method for providing a video stream including video fragments of a predetermined quality to a cloud server in response to a video download request from a cloud server, A user terminal configured to perform a video content request to a cloud server and to play back an image stream provided from the cloud server and to output the image stream to the cloud server; A video streaming processing rate for a video stream provided from the video server, and a video streaming rate for a video stream provided from the video server to the user terminal, And the image quality of the video stream is improved by setting the video quality higher as the conversion ratio and the round trip time decrease, And a cloud server configured to generate video download request information for providing the video download request information to the video server.

여기서, ratio 는 변환비율이고, V 는 비디오 스트리밍 처리율, I는 이미지 스트리밍 처리율.The cloud server calculates a conversion rate which is a ratio of a video streaming processing rate from downloading a video stream from the video server to converting the video stream to an image stream and an image streaming processing rate for performing screen reproduction processing on the image stream from the user terminal , And a conversion ratio is calculated according to the following equation. ≪ EMI ID = 1.0 >

Here, ratio is a conversion ratio, V is a video streaming processing rate, and I is an image streaming processing rate.

여기서, 상기 sratio_i 는 가중평균 변환비율이고, ratio 는 현재 산출된 변환비율, β는 가중치, sratio_i-1 는 이전 가중평균 변환비율.Also, the cloud server is configured to calculate a weighted average round trip time for the current conversion ratio as follows: < EMI ID = 1.0 > wherein the network environment adaptive cloud A streaming service providing system is provided.

Here, sratio _i is a weighted average conversion ratio, ratio is a currently calculated conversion ratio,? Is a weighting factor, and sratio _i-1 is a previous weighted average conversion ratio.

여기서, 상기 srtt_i 는 가중평균 왕복시간이고, rtt 는 현재 산출된 왕복시간, α는 가중치, srtt_i-1 는 이전 이미지 스트림에 대한 가중평균 왕복시간.The cloud server calculates the weighted average round trip time for the round trip time of the image stream and sets the video quality down if the round trip time is equal to or greater than the weighted average round trip time. A cloud streaming service provision system is provided.

Here, the srtt _i is the weighted average round-trip time, rtt is currently calculating the round trip time, α is the weight, srtt _i-1 is the weighted average of the round trip time for a previous image stream.

Also, the conversion ratio weight α and the round-trip time weight β are set to 0.125. The network environment adaptive cloud streaming service providing system is provided.

Also, the cloud server is configured to automatically set a video quality setting period so as to correspond to a video fragment playback period of a video stream provided from a video server.

In addition, the cloud server is configured to set the video quality to the lowest level in the event of loss of video fragments or loss of images, thereby providing a network environment adaptive cloud streaming service providing system.

In addition, the cloud server is configured to generate a plurality of virtual desktops, perform video stream and image stream transmission / reception processing between the video server and the user terminal through the virtual desktop, and perform video quality setting processing for each virtual desktop A network environment adaptive cloud streaming service providing system is provided.

According to another aspect of the present invention, there is provided a video server for performing a video download request to a video server for a video content request from a user terminal in a cloud server, A method for providing a cloud streaming service in which a video piece of a predetermined quality is converted into an image stream and is provided to the user terminal, the method comprising: receiving a video stream from a video server and converting the video stream into an image stream; A second step of calculating an image streaming processing rate corresponding to a screen reproduction time of the image stream from the user terminal in the cloud server, a second step of calculating a video streaming processing rate calculated in the first step A third step of calculating a conversion ratio based on the video streaming processing rate and the image streaming processing rate calculated in the second step, a fourth step of calculating a round trip time according to transmission and reception of an image stream with the user terminal in the cloud server, A fifth step of setting the video quality higher as the conversion ratio calculated in the third step and the round trip time calculated in the fourth step are decreased and providing video download request information including the video quality information to the video server; And a sixth step of generating a video stream including video fragments corresponding to the video quality of the video download request information from the cloud server in the video server and providing the video stream to the cloud server. How streaming service is provided Is provided.

여기서, ratio 는 변환비율이고, V 는 비디오 스트리밍 처리율, I는 이미지 스트리밍 처리율.Also, in the third step, the conversion ratio is calculated according to the following equation: < EMI ID = 1.0 >

Here, ratio is a conversion ratio, V is a video streaming processing rate, and I is an image streaming processing rate.

여기서, 상기 sratio_i 는 가중평균 변환비율이고, ratio 는 현재 산출된 변환비율, β는 가중치, sratio_i-1 는 이전 가중평균 변환비율.In the fifth step, the cloud server calculates a weighted average conversion ratio with respect to a current conversion ratio according to the following equation, and sets the video quality down if the current conversion ratio is equal to or larger than the weighted average conversion ratio A network environment adaptive cloud streaming service providing method is provided.

Here, sratio _i is a weighted average conversion ratio, ratio is a currently calculated conversion ratio,? Is a weighting factor, and sratio _i-1 is a previous weighted average conversion ratio.

여기서, 상기 srtt_i 는 가중평균 왕복시간이고, rtt 는 현재 산출된 왕복시간, α는 가중치, srtt_i-1 는 이전 이미지 스트림에 대한 가중평균 왕복시간.In the fifth step, the cloud server calculates a weighted average round trip time for the round trip time of the image stream, and sets the video quality down if the round trip time is equal to or greater than the weighted average round trip time. A network environment adaptive cloud streaming service providing method is provided.

Here, the srtt _i is the weighted average round-trip time, rtt is currently calculating the round trip time, α is the weight, srtt _i-1 is the weighted average of the round trip time for a previous image stream.

In the first step, the cloud server extracts a video fragment loss based on a video stream provided from a video server. In the second step, the cloud server extracts an image Wherein the cloud server sets the video quality to the lowest level when a video fragment loss occurs in the first step or an image loss occurs in the second step in the fifth step. A method for providing an environment adaptive cloud streaming service is provided.

According to the present invention, in the cloud server, the video stream quality is improved based on the conversion rate calculated based on the video streaming processing rate according to the network state between the video servers and the image streaming processing rate according to the network state between the user terminals and the image stream round- It is possible to continuously provide video playback through the user terminal and to improve the video playback quality on the screen.

Brief Description of the Drawings Fig. 1 is a schematic diagram of a system for providing a network environment adaptive cloud streaming service according to a first embodiment; Fig.
FIG. 2 is a block diagram showing the internal configuration of the cloud server 300 shown in FIG. 1 functionally separated. FIG.
FIG. 3 illustrates a virtual desktop infrastructure (VDI) model for the data processing module 360 shown in FIG.
FIG. 4 is a block diagram illustrating functions of the quality setting module 350 shown in FIG. 2. FIG.
FIG. 5 is a diagram for explaining a cloud streaming service method in the network environment adaptive cloud streaming service providing system shown in FIG. 1; FIG.
FIG. 6 and FIG. 7 are diagrams showing experimental results in which a bottleneck occurs in an image stream network and a video streaming network in a congested network environment, according to a system. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings. It is to be noted that like elements in the drawings are denoted by the same reference numerals whenever possible. It should be understood, however, that the terminology or words of the present specification and claims should not be construed in an ordinary sense or in a dictionary, and that the inventors shall not be limited to the concept of a term It should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be properly defined. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention, and not all of the technical ideas of the present invention are described. Therefore, It is to be understood that equivalents and modifications are possible.

FIG. 1 is a diagram illustrating a schematic configuration of a system for providing a network environment adaptive cloud streaming service according to a first embodiment of the present invention.

1, the network adaptive cloud streaming service providing system according to the present invention includes a video server 100, a user terminal 200, and a cloud server 300. In this case, the interval between the video server 100 and the cloud server 300 is a video streaming network based on the HTTP protocol according to the type of streaming, and a period during which the user accesses the cloud environment, that is, between the cloud server 300 and the user terminal 200 ) Is divided into an image streaming network based on RFB (Remote Frame Buffer). Herein, the video streaming network or the image streaming network may be a wired or wireless communication network.

The video server 100 is an apparatus for supplying video content to the cloud server 300 and may be configured as a Dynamic Adaptive Streaming over HTTP (DASH) server. The video server 100 stores the video contents in the form of video pieces according to quality. In this case, the quality criterion for the video fragments may be a bit rate, a resolution, an encoding codec, a number of frames per second, a reproduction period, and the like.

In addition, the video server 100 generates a video stream including video piece information and quality state information corresponding to the video piece in response to a request from the cloud server 300, and provides the video stream to the cloud server 300 . The quality status information for the video piece includes quality description information and a media description file such as a file name, an encoding codec format, and the like of a video piece file by quality.

The user terminal 200 accesses the cloud server 300 to request video content, receives the corresponding video content related image information from the cloud server 300, and reproduces the video content on the screen.

The cloud server 300 performs a video downloading request to the video server 100 based on a video content request from the user terminal 200 and transmits a video download request to the video server 100, To an image, and generates an image stream, and provides the image stream to the user terminal 200. At this time, the cloud server 300 performs image conversion processing on the video fragments based on the quality status information included in the video stream.

The cloud server 300 monitors a video streaming network environment with the video server 100 and an image streaming network environment between the user terminal 200 and the video server 100, In addition, the video server 100 is configured to perform video download request processing of video quality corresponding to the current network status. Here, the video quality setting process is performed in real time every predetermined period while the video is reproduced, and this process is repeated until the downloading of the corresponding video content is completed. At this time, the video quality setting period is automatically changed and set so as to correspond to the video piece playback period of the video stream provided from the video server 100. [ This corresponds to the video download request period including the video quality. By changing the video download request period with reference to the video fragment playback period, the download request cycle is delayed due to the change in the quality of the video fragments, In order to prevent the problem. Preferably, the video download request period is set to be within 1/4 of the video fragment reproduction period.

FIG. 2 is a block diagram showing the internal structure of the cloud server 300 shown in FIG. 1 functionally separated.

2, the cloud server 300 includes a video network communication unit 310, an image network communication unit 320, a video network monitoring module 330, an image network monitoring module 340, a quality setting module 350 ), And a data processing module 360. [

The video network communication unit 310 is an interface for performing communication with the video server 100 and performs HTTP based data transmission / reception processing through, for example, a web socket of HTML5.

The image network communication unit 320 is an interface for performing communication with the user terminal 200.

The video network monitoring module 330 extracts a download time for video data received through the video network communication unit 310 and calculates a video streaming throughput based on the download time. At this time, the download time is composed of the start and finish time of video data reception, and extracts each video stream. In addition, the video network monitoring module 330 extracts a video fragment loss during a predetermined period based on a video stream. Also, the video network monitoring module 330 may be provided with a DASH-JS supporting only the standard DASH or a hjs.js player using a daily motion for using the HLS technique.

The image network monitoring module 340 extracts a transmission / reception time of an image stream transmitted / received through the image network communication unit 320 using a pcap library for capturing a packet, and calculates an image streaming throughput based on the transmission / reception time . In addition, the image network monitoring module 340 extracts loss of image stream for a predetermined period.

The quality setting module 350 determines a video quality based on a data round-trip time and a conversion rate provided to the video network monitoring module 330 and the image network monitoring module 340. That is, the quality setting module 350 sets the video quality higher as the round trip time of the image stream is lower and the conversion ratio is decreased according to the network environment.

The data processing module 360 performs a process of converting a video piece provided from the video server 100 into an image form, and also performs a process of converting a video download request including video quality information determined by the quality setting module 350 And provides the generated information to the video server 100.

Meanwhile, in the present invention, the data processing module 360 may be implemented as a virtual desktop infrastructure (VDI) model for multimedia streaming operation processing for a plurality of user terminals 200. That is, as shown in FIG. 3, the hypervisor 361 and the plurality of virtual desktops 362 ₁ to 362 _N may be configured for virtual desktop generation. The video network monitoring module 330 and the image network monitoring module 340 monitor the network status between the video server 100 and the user terminal 200 for each of the virtual desktops 362 ₁ to 362 _N , And may be configured to be respectively provided to the desktops 362 ₁ to 362 _N.

In FIG. 3, the hypervisor 361 generates or allocates a virtual desktop 362 to the user terminal 200 based on a service request from the user terminal 200. The virtual desktop 362 performs a communication process with the user terminal 200 and the video server 100 and the series of data conversion processes described above.

That is, in FIG. 3, the cloud server 300 sets the video quality according to the network environment and the data conversion ratio between the video server 100 and the user terminal 200 for each of the desktops 362 ₁ to 362 _N.

FIG. 4 is a block diagram illustrating the function of the quality setting module 350 shown in FIG.

4, the quality setting module 350 includes a round trip time calculation block 351, a weighted average round trip time calculation block 352, a conversion ratio calculation block 353, a weighted average conversion ratio calculation block 354, , And a video quality setting block 355.

The round trip time calculation block 351 calculates the round trip time for the image packet. At this time, the round-trip time calculation block 351 calculates the transmission / reception time between two image packets based on the serial number of the image packet provided from the image network monitoring module 340 and the reception acknowledgment number of the image packet of the serial number , Calculates the round trip time

The weighted average round trip time calculation block 352 calculates a weighted average round trip time by applying a predetermined weight to the round trip time calculated in the round trip time calculation block 351. [ The weighted average round trip time srtt _i is calculated as shown in Equation (1).

Where rtt is the round trip time, a is the weight, and srtti _-1 is the weighted average round trip time for the previous image stream. At this time, the weight (alpha) may be set to 0.125.

The conversion ratio calculating block 353 calculates the conversion ratio using the video streaming throughput V and the image streaming throughput I. The conversion ratio is calculated as a ratio of the video streaming throughput V and the image streaming throughput I, as shown in Equation (2).

The video streaming processing rate V is a real time value for one video piece and is the amount of data transmitted per second until the downloading of the video piece data provided from the video server 100 is completed. In addition, the image streaming throughput I is the amount of reproduction data per second before the image packet is displayed on the screen of the user terminal 200.

The weighted average conversion ratio calculating block 354 calculates a weighted average conversion ratio by applying a predetermined weight to the conversion ratio calculated by the conversion ratio calculating block 353. The weighted average conversion ratio sratio _i is calculated as shown in Equation (3).

Where ratio is the conversion rate, β is the weight, and sratio _i-1 is the previous weighted average conversion rate. At this time, the weight value beta may be set to 0.125.

The quality setting block 355 compares the comparison result between the round trip time and the weighted average round trip time with the comparison result between the conversion ratio and the weighted average conversion graying with predetermined quality condition information and sets the current video quality to correspond to the result do.

That is, the quality setting block 355 sets the video quality higher when the round trip time is less than the weighted average round trip time and the conversion ratio is less than the weighted average conversion rate. The quality setting block 355 also sets the video quality down if the round trip time exceeds the weighted average conversion rate or the conversion rate exceeds the weighted average conversion rate. Also, the quality setting block 355 maintains the video quality when the round trip time and the weighted average round trip time are the same and the conversion ratio is equal to the weighted average conversion ratio.

At this time, the quality setting block 355 includes a lookup table (not shown) that includes a video quality level corresponding to the difference between the round trip time and the weighted average round trip time, and a video quality level corresponding to the difference between the conversion ratio and the weighted average conversion ratio The video quality can be set based on the first video quality level corresponding to the round trip time and the weighted average round trip time difference and the average value between the second video quality level corresponding to the difference between the conversion ratio and the weighted average conversion rate. At this time, it is also possible to assign different weights to the first video quality level and the second video quality level, and set the video quality to correspond to the average value.

In addition, the quality setting block 355 determines whether the conversion rate is "0" or " 0 " as the image streaming processing rate or the video streaming processing rate is set to "0 " If it has a value of "", the video quality is set to the lowest level irrespective of the round trip time.

In addition, when the loss occurrence information for the video stream or the image stream is generated from the video network monitoring module 330 or the image network monitoring module 340, the quality setting block 355 determines whether or not the loss occurrence information Set the video quality to the lowest level.

Next, a cloud streaming service method in a network environment adaptive cloud streaming service providing system having the above-described configuration will be described with reference to FIG. Hereinafter, a system implemented by an infrastructure (VDI) model in which the cloud server 300 performs data processing through a virtual desktop as shown in FIG. 3 will be described.

First, when a user requests a connection to the cloud server 300 through the user terminal 200 (ST10), the cloud server 300 transmits a virtual desktop 362 for performing video data processing to the user terminal 200 (ST20). That is, the cloud server 300 allocates one virtual desktop 362 to the user terminal 200.

When the virtual desktop 362 of the cloud server 300 receives a video service request from the user terminal 200 in step 30 and the virtual desktop 362 receives a service request from the user terminal 200 And provides video download request information including video content information to the video server 100 (ST40).

The video server 100 retrieves the requested video content information from the virtual desktop 362, generates a video stream including the video fragments for the retrieved video content, and provides the video stream to the virtual desktop 362 (ST50). At this time, the video server 100 may be configured to include a video piece of a predetermined reference quality when an initial video stream is generated. For example, the reference quality may be set to medium quality. In addition, the reference quality may be set to an average level of the current video quality level of the other virtual desktop.

When a video stream is received from the video server 100, the virtual desktop 362 converts the received video stream into an image stream (ST60).

In addition, the virtual desktop 362 calculates the video throughput based on the state of the video network formed with the video server 100 (ST70). At this time, the virtual desktop 362 calculates the video throughput based on the video network status information including the download time and the image stream conversion time for the corresponding video stream.

In addition, the virtual desktop 362 transmits the converted image stream to the user terminal 200 (ST80). At this time, the user terminal 200 plays back the image stream and displays it on the screen. In addition, when the playback process is completed, the user terminal 200 transmits the playback completion information for the corresponding image stream to the corresponding virtual desktop 362 (ST90).

The virtual desktop 362 calculates an image stream round trip time and an image streaming throughput corresponding to the image network state formed with the user terminal 200 (ST100).

Next, the virtual desktop 362 sets the video quality corresponding to the video network state and the image network state based on the video processing rate calculated in step ST70, the image processing rate calculated in step ST100, and the data round trip time information ST110). At this time, the virtual desktop 362 calculates the weighted average round trip time for the round trip time, compares the round trip time and the weighted average round trip time, and calculates the conversion ratio based on the video processing rate and the image processing rate, The weighted average conversion time is calculated to compare the conversion rate with the weighted average conversion rate. Then, the video quality corresponding to the comparison result of the round trip time and the conversion ratio is determined.

Then, the virtual desktop 362 provides download request information including video quality information set in consideration of the network status to the video server 100 (ST120).

Then, the video server 100 generates a video stream including a video piece corresponding to the video quality information provided from the virtual desktop 362, and provides the video stream to the corresponding desktop 362 (ST130).

It goes without saying that the above-described series of operations are repeatedly performed until all of the video fragments corresponding to the video contents are transmitted or the service stop request is requested by the user.

On the other hand, in the present invention, the cloud server 300 is configured to set the video quality to the lowest level when image reproduction is not performed from the user terminal 200, or when a video piece loss or an image loss occurs.

FIGS. 6 and 7 are results of analysis of bottlenecks in an image stream network and a video streaming network in a congested network environment. 6 and 7 show performance comparison results in the DASH system (DASH), the HLS system (HLS), and the network environment adaptive cloud streaming system (QADASH, QoE-aware DASH) according to the present invention. Here, the DASH system is a system to which adaptive bit rate streaming technique of a moving picture expert group is applied, and HLS is a system to which Apple's HTTP Live Streaming technique is applied.

FIG. 6 shows a system analysis result for a congested image streaming network. FIG. 6 (A) is a comparison chart of the perceived quality of each system, and FIG. 6 (B) shows a conversion rate trend.

6A is an experimental result on the average conversion ratio, the number of screen loss, and the reproduction delay time for each system. This is the experimental result when the video network section of the whole network has a loss rate of 10 ^-3 and a delay time of 20 ms, and the image network section has a loss rate of 10 ^-2 and a delay time of 170 ms. That is, it can be seen that the network environment adaptive cloud streaming system (QADASH) according to the present invention is close to an ideal average conversion ratio (for example, 50) than the DASH system, and the screen loss and delay time are low .

FIG. 6 (B) shows the results of FIG. 6 (A) in terms of the real-time conversion rate trend, and it is confirmed that the network environment adaptive cloud streaming system (QoE-aware DASH) according to the present invention is stable . Especially, it shows that the conversion rate is lower than that of the other systems, and is adaptively adjusted to the network situation, thereby improving the quality of the video experience.

FIG. 7 shows a system analysis result for a congested video streaming network. FIG. 7 (C) shows a perceived quality comparison chart for each system, and FIG. 7 (D) shows a conversion rate trend.

7 (C) is an experimental result on the average conversion ratio, the number of screen loss, and the reproduction end time for each system. This is the experimental result when the video network interval is 10 ^-2 and the delay time is 50 ms and the image network interval is 10 ^-3 and the delay time is 20 ms in the entire network. That is, it can be confirmed that the network environment adaptive cloud streaming system (QADASH) according to the present invention is close to an average conversion ratio (for example, 50) which is more ideal than the DASH, and also provides a normal video streaming service with zero screen loss, The playback end time is also known to be the fastest.

In FIG. 7, (D) shows the result of (C) in terms of the real-time conversion rate trend, and it can be confirmed that the network environment adaptive cloud streaming system (QADASH) according to the present invention is stable without abrupt change. It can be seen that the video quality is adjusted adaptively to the network situation, thereby improving the quality of the video experience of the user and providing the continuous streaming service.

100: video server, 200: user terminal,
300: Cloud server,
310: video network communication unit, 320: image network communication unit,
330; Video network monitoring module, 340: image network monitoring module,
350: quality setting module, 360: data processing module,
361: hypervisor, 362: virtual desktop.

Claims (13)

A video server for storing video fragment information by quality for video content and providing a video stream including a video fragment of a predetermined quality to a cloud server in response to a video download request from the cloud server;
A user terminal configured to perform a video content request to a cloud server, reproduce an image stream provided from the cloud server and output the reproduced image stream,
Performing a video download request to the video server for a video content request from the user terminal, converting the video stream received from the video server into an image stream and providing the video stream to the user terminal, A conversion rate calculated on the basis of a video streaming throughput rate of a stream and an image streaming throughput rate of a user terminal and a round trip time of an image stream with the user terminal are acquired and the video quality is increased as the conversion rate and round trip time are decreased And a cloud server configured to generate video download request information including the video quality information, and to provide the video download request information to the video server. The network environment adaptive cloud streaming service providing system according to claim 1,
The method according to claim 1,
Wherein the cloud server calculates a conversion rate which is a ratio of a video streaming processing rate from downloading a video stream from the video server to converting the video stream into an image stream and an image streaming processing rate performing screen reproduction processing on the image stream from the user terminal, And the ratio is calculated according to the following equation. ≪ EMI ID = 1.0 >

Here, ratio is a conversion ratio, V is a video streaming processing rate, and I is an image streaming processing rate.
The method according to claim 1,
The cloud server calculates a weighted average conversion ratio with respect to the current conversion ratio as shown in the following equation,
And if the current conversion rate is equal to or greater than the weighted average conversion rate, the video quality is set to a lower level.

Here, sratio _i is a weighted average conversion ratio, ratio is a currently calculated conversion ratio,? Is a weighting factor, and sratio _i-1 is a previous weighted average conversion ratio.
The method according to claim 1,
The cloud server calculates a weighted average round trip time for the image stream round trip time as shown in the following equation,
And when the current round trip time is equal to or greater than the weighted average round trip time, the video quality is set to be lower.

Here, the srtt _i is the weighted average round-trip time, rtt is currently calculating the round trip time, α is the weight, srtt _i-1 is the weighted average of the round trip time for a previous image stream.
The method according to claim 3 or 4,
Wherein the conversion ratio weight α and the round trip time weight β are set to 0.125.
The method according to claim 1,
Wherein the cloud server is configured to automatically change a video quality setting period so as to correspond to a video fragment reproduction period of a video stream provided from a video server.
The method according to claim 1,
Wherein the cloud server is configured to set the video quality to the lowest level when a video fragment loss occurs or an image loss occurs.
The method according to claim 1,
Wherein the cloud server is configured to generate a plurality of virtual desktops and perform video stream and image stream transmission / reception processing between the video server and the user terminal through the virtual desktop, and to perform video quality setting processing for each virtual desktop Network Adaptive Cloud Streaming Service Provisioning System.
The cloud server performs a video download request to the video server for the video content request from the user terminal, converts the video fragments of a certain quality contained in the video stream received from the video server into an image stream, A method for providing a cloud streaming service,
A first step of calculating a video streaming processing rate corresponding to a time from downloading of a video stream provided from a video server to conversion to an image stream in a cloud server,
A second step of calculating an image streaming processing rate corresponding to a screen reproduction time of the image stream from the user terminal in the cloud server,
A third step of calculating a conversion ratio on the basis of the video streaming processing rate calculated in the first step and the image streaming processing rate calculated in the second step in the cloud server,
A fourth step of calculating a round trip time according to transmission and reception of an image stream with a user terminal in a cloud server,
Setting the video quality higher as the conversion rate calculated in the third step and the round trip time calculated in the fourth step are decreased in the cloud server and providing the video download request information including the video quality information to the video server In a fifth step,
And generating a video stream including video fragments corresponding to the video quality of the video download request information from the cloud server in the video server and providing the video stream to the cloud server. The network environment adaptive cloud streaming Service delivery method.
10. The method of claim 9,
Wherein the conversion rate in the third step is calculated according to the following equation: < EMI ID = 15.0 >

Here, ratio is a conversion ratio, V is a video streaming processing rate, and I is an image streaming processing rate.
10. The method of claim 9,
In the fifth step, the cloud server calculates a weighted average round trip time for the current conversion ratio as shown in the following equation,
And if the current conversion rate is equal to or greater than the weighted average conversion rate, the video quality is lowered.

Here, sratio _i is a weighted average conversion ratio, ratio is a currently calculated conversion ratio,? Is a weighting factor, and sratio _i-1 is a previous weighted average conversion ratio.
10. The method of claim 9,
In the fifth step, the cloud server calculates a weighted average round trip time for the round trip time of the image stream as shown in the following equation,
And if the current round trip time is equal to or greater than the weighted average round trip time, the video quality is set to be lower.

Here, the srtt _i is the weighted average round-trip time, rtt is currently calculating the round trip time, α is the weight, srtt _i-1 is the weighted average of the round trip time for a previous image stream.
10. The method of claim 9,
In the first step, the cloud server extracts a video fragment loss based on a video stream provided from a video server,
In the second step, the cloud server extracts image loss based on the reproduction completion information provided from the user terminal,
Wherein the cloud server sets the video quality to the lowest level when a video fragments loss occurs in the first step or an image loss occurs in the second step in the fifth step. The network environment adaptive cloud streaming service Delivery method.

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