KR20170034097A

KR20170034097A - Method for adaptive streaming and Apparatus therefor

Info

Publication number: KR20170034097A
Application number: KR1020150132347A
Authority: KR
Inventors: 이윤주; 박우출
Original assignee: 전자부품연구원
Priority date: 2015-09-18
Filing date: 2015-09-18
Publication date: 2017-03-28

Abstract

According to an aspect of the present invention, there is provided an adaptive streaming service method comprising: comparing a transmission rate of a segment being received and a transmission rate of a network; And determining a transmission rate of a next segment to be received as a first method when the transmission rate of the network is higher as a result of the comparison, and when a transmission rate of the segment being received is higher as a result of the comparison, The method comprising: determining an absolute value of a difference between a data rate of the network and a data rate of the segment being received; And if the difference is greater than a predetermined threshold value, determining a transmission rate of the segment being received and an average value of a transmission rate of the network to a value equal to or greater than a predetermined threshold, And determines a transmission rate of the segment to be received.

Description

TECHNICAL FIELD The present invention relates to an adaptive streaming service method and apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data streaming, and more particularly, to an apparatus and method using HTTP adaptive streaming.

With the recent development of mobile devices and wireless communication technologies such as smart phones, it has become possible to use the Internet anytime and anywhere. Therefore, multimedia services through the Internet have been diversified and multimedia contents have been provided to various platforms, so that the requirements of the users are increasing and problems of service quality are increasing.

In order to solve this problem, a variety of systems are being tried to utilize the network efficiently and to improve the quality of the contents. HTTP adaptive stream has recently attracted attention as one of them.

Conventionally, streaming service on the Internet serves only one image quality provided by the server. The streaming method uses a dedicated streaming protocol such as RTSP (Real-Time Streaming Protocol) It was a method to receive from the media server.

Recently, however, a progressive download method has been used to buffer and play media contents using a web standard protocol, HTTP, in video services such as YouTube.

Unlike the existing streaming method, it is possible to access the media service by using the Internet anytime and anywhere using the conventional structural system supporting HTTP, and it is possible to efficiently use the network by using the cache or proxy servers existing on the Internet There are advantages.

In recent years, HTTP adaptive streaming has been attracting attention as a hybrid transmission method utilizing the advantage of the HTTP protocol and utilizing the advantage of a streaming method in which a video is directly requested from a server and played by a service.

HTTP adaptive streaming is based on TCP, so network security is guaranteed and services are not restricted by firewalls or routers.

In addition, since it is possible to use the existing infrastructure without using a new server for the streaming service, it is possible to save the cost, and it is easy to construct and load of the server is small because it is not required to maintain a session for streaming .

However, since the HTTP adaptive streaming service has to change the transmission rate according to the change of the network state, when there is a sudden change in the network state, especially when the available transmission bandwidth is sharply decreased, the service suspension due to the underflow of the user receiving buffer Or the transmission rate of the user receiving apparatus due to the frequent change of the network state is also continuously changed.

These problems are becoming more and more evident as the number of video contents is increasing recently and the demand for streaming high-quality large-capacity contents such as 4K UHD (Ultra High Definition) video is increasing.

SUMMARY OF THE INVENTION The present invention has been made in view of the technical background as described above, and it is an object of the present invention to provide a method and apparatus for streaming multimedia content of high quality and high capacity, which minimizes a change in a transmission rate, minimizes a service stop due to an underflow of a reception buffer, And an object thereof is to provide a device and a method for providing streaming to a user.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to another aspect of the present invention, there is provided an adaptive streaming apparatus including at least one processor, the controller including: a controller for comparing a transmission rate of a segment being received with a transmission rate of a network to determine a transmission rate of a segment to be received next; A data request unit for requesting the data server to transmit the next segment to be received at a data rate determined by the controller; And a data receiving unit receiving data of the segment at a data rate determined by the control unit. Wherein the control unit compares a data rate of the currently received segment with a data rate of the network; And determining a transmission rate of a next segment to be received as a first method when the transmission rate of the network is higher as a result of the comparison, and when a transmission rate of the segment being received is higher as a result of the comparison, And determining a transmission rate of the next segment to be received, by determining a transmission rate of the next segment to be received.

According to the present invention, even when the network status continuously changes, there is an effect that a large-capacity multimedia content can be stably provided to a user without a drawback such as an underflow, without frequent change of the transmission rate.

1 and 2 are flowcharts illustrating an adaptive streaming method according to an embodiment of the present invention.
3 is a structural diagram of an adaptive streaming apparatus according to another embodiment of the present invention;
4 is a structural diagram of a computer system in which an adaptive streaming method according to another embodiment of the present invention is implemented;

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the terms " comprises, " and / or "comprising" refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The HTTP adaptive streaming apparatus and method according to the present invention is based on MPEG-DASH (Dynamic Adaptive Streaming over HTTP) in order to overcome the disadvantage of existing HTTP adaptive streaming.

The MPEG-DASH-based adaptive streaming service determines the data rate at the receiver of the user requesting the service.

The receiving apparatus first receives the MPD (Media Presentation Description) file from the HTTP server and requests the web server for the segment file of the file to be streamed using the information included in the MPD file.

At this time, an adaptive streaming technique is needed to determine the optimal transmission rate of the segment file, and the transmission rate is determined considering various factors.

Factors for determining the transmission rate include the state of the reception buffer of the reception device, the transmission state of the network, the transmission rate change by the user request, and the resource or computing power of the reception device.

If the buffer status of the receiving apparatus is in a stable state, it is necessary to adjust the transmission rate to be increased or decreased according to the underflow or overflow when there is no problem, and if the transmission rate of the network is bad, , An underflow may occur. Therefore, it is necessary to make an adjustment to lower the transmission rate.

Also, in addition to the transmission rate reflecting the environmental factors described above, when a user requests more high-quality contents, the transmission rate must be increased. When the resource or computing power of the receiving apparatus is lower than the transmission rate, You have to lower the bit rate before you lose.

In addition, when streaming is performed using a CDN (Content Delivery Network) or a CCN (Cloud Computing Network) scheme, the available data rate may vary depending on whether a cache hit occurs or not.

1 is a flowchart of a transmission rate control method according to the present invention, wherein NR is a network transmission rate, CSR is a transmission rate of a currently received segment, CV is a threshold value, and NSR is a transmission rate of a segment to be received next.

According to the transmission rate determination method of the present invention, whether to increase the transmission rate of the network is first determined (S110), and the transmission rate is determined by dividing the transmission rate by the increase or decrease of the network transmission rate.

In streaming, data is received on a segment-by-segment basis. However, there is no risk of underflow when the network transmission rate is higher than the bitrate of the currently received segment, that is, Can make the user feel uncomfortable, so that the transmission rate can be adjusted so that the transmission rate can be changed without changing according to the situation.

That is, it is determined whether the increase rate of the transmission rate is greater than a preset threshold value (S120). If the increase rate is smaller than the predetermined threshold value, the current transmission rate is maintained to reduce the inconvenience of the user due to the change of the transmission rate (S140) (S130).

For example, if the transmission rate of the currently reproduced image is 100 kbps and the transmission rate of the segment being received is 100 kbps, the network transmission rate is 110 kbps and the threshold value is 50 kbps, then the increase rate is 10 kbps and less than the threshold value of 50 kbps Therefore, the transmission rate is maintained at 100 kbps.

This is because the improvement of the image quality due to the increase of the transmission rate may cause the user's discomfort due to the change of the transmission rate rather than the user's satisfaction to be felt larger.

On the other hand, if the transmission rate of the currently reproduced image is 100 kbps and the transmission rate of the currently received segment is 100 kbps, if the transmission rate of the network is improved to 200 kbps, that is, if the transmission rate increases beyond the threshold value of 50 kbps, The transmission rate should be adjusted upward.

However, if the transmission rate doubles from 100kbps to 200kbps, the picture quality will be improved, but the user may feel the disparity in the sudden change in picture quality. Therefore, it is possible to use a method of increasing the transmission rate gradually so that the user can not detect the change of the transmission rate. The average transmission rate of the currently received segment and the average value of the network transmission rate are used as the transmission rate of the next segment (S130).

For example, when the network transmission rate is changed from 100 kbps to 200 kbps, it is adjusted to 150 kbps, which is an average value of two values rather than 200 kbps, and 175 kbps, which is an average value of 150 kbps and 200 kbps in the next segment.

In the case of 175kbps, since the difference value from 200kbps is smaller than the threshold value, 175kps is maintained without changing the transmission rate any more.

If you use this method, 175 kbps, which is less than the network transmission rate of 200 kbps, is always maintained, which may be a disadvantage of not fully utilizing the network transmission rate.

Therefore, if the difference between the network transmission rate and the current transmission rate is greater than the threshold value, the transmission rate adjustment method according to another embodiment of the present invention divides the difference between the network transmission rate and the current transmission rate into predetermined values, I use the way to add up until.

For example, if the current transmission rate is 100kbps and the network transmission rate is increased to 200kbps, the difference between the two exceeds 50kbps, which is the threshold value. Therefore, if the difference between the network transmission rule and the current transmission rate is 100kbps divided by 5, And if it is added to the current transmission rate of 100 kbps for each segment, it can be 120 kbps and 140 kbps, and after the five segments, the network transmission rate can be 200 kbps.

The number of division of the difference value, that is, the number of steps leading to the network transmission rate, the connection quality is smoothly changed due to the small change in the image quality between the segments, but it may cause inconvenience to the user due to various stages of change. On the contrary, The number of steps should be determined considering the fact that there is a disadvantage that the image quality is rapidly changed due to a sudden transmission rate change between the segments.

Unlike the above case, if the network transmission rate is lower than the transmission rate of the currently received segment (S200), there is a possibility of data underflow. Therefore, the transmission rate should be adjusted in a manner different from the case of increasing the transmission rate.

2 shows a method of adjusting the transmission rate when the network transmission rate decreases.

If the difference between the transmission rate of the currently received segment and the network transmission rate is compared with the threshold value (S210) and there is a risk of underflow when the difference is larger than the threshold value, there is a sudden change in image quality. It should be reduced to the network transmission rate (S220).

On the other hand, when the difference in the data rate is smaller than the threshold value, it is possible to adjust the data rate by referring to the amount of data remaining in the buffer.

That is, the receiving bit rate of the next segment is lowered in accordance with the network condition (S230), and the reproducing bit rate is maintained at the same value as the bit rate of the current segment (S240).

For example, if the transmission rate of the currently reproduced image is 100 kbps and the transmission rate of the segment being received is 100 kbps, the image can be continuously reproduced without any underflow or overflow problem.

However, if the network transmission rate is reduced to 50 kbps and the data rate of the segment being received is 50 kbps, an image having a data rate of 100 kbps requires 100 kbit data per second, and receives only 50 kbit data per second.

However, if 200k bits of data is stored in the buffer, it is possible to reproduce an image having a transmission rate of 100 kbps without receiving the data for 2 seconds. Therefore, the transmission rate of the segment being received is maintained at 50 kbps, It is possible.

Therefore, if the remaining buffer amount is divided by the current reproduction rate minus the network transmission rate, the reproduction bit rate of the image or media can be calculated to maintain the same value as the current reproduction rate while receiving data at the current network transmission rate (S250) . This can be expressed by the following equation (1).

Where T is the amount of time (in seconds) that the playback rate of the current media can be maintained in spite of a decrease in the network transmission rate, BUFFER is the amount of data remaining in the buffer, CSR is the current segment transmission rate in bits / Network bit rate (bit / sec).

The segment transmission rate during the time T thus obtained may be as low as the network transmission rate, but the reproduction bit rate may be kept high (S260, S270).

If the network bit rate is equal to or greater than the bit rate of the current video or media while maintaining the reproduction bit rate of the current video or media using the data of the buffer, the user can continue reproduction without changing the video bit rate, There is an advantage that it can not feel the situation of the network.

FIG. 3 shows a schematic diagram of an adaptive streaming apparatus 300 according to another embodiment of the present invention.

The adaptive streaming apparatus 300 includes a data receiving unit 310, a control unit 320, and a data requesting unit 330.

Adaptive streaming determines the transmission rate of media such as video and the like and requests media of the transmission rate to the media server by determining the transmission rate of the media. Therefore, the control unit 320 considers the transmission rate of the currently received segment, the bit rate of the media being reproduced, The transmission rate of the next segment is determined.

The method of determining the transmission rate in the controller 320 is the same as the transmission rate determination method of the above-described adaptive streaming method, such as comparing the transmission rate of the current segment with the size of the network transmission rate and considering whether the network status is improved or deteriorated.

When the control unit 320 determines the data rate, the data request unit 330 requests the media server to transmit the data at the determined data rate.

The media server that receives the request transmits the media data at the corresponding transmission rate, and the adaptive streaming device 300 receives the media data through the data receiving unit 310 and plays the media data.

As another embodiment of the case where the network transmission rate is reduced, it is also possible to use a method using an additional receiving apparatus.

In a typical home or office environment, data streaming is accomplished using high-speed Internet or Wi-Fi networks. LTE or other mobile communication networks or mobile Internet communications such as WiBro to supplement the environment of a worsened communication network.

That is, in the general communication environment, the adaptive streaming apparatus 300 according to the present invention uses two or more independent receiving apparatuses in the data receiving unit 310, while the high-speed wired Internet, Wi-Fi, It enables stable streaming using wired internet, Wi-Fi, mobile communication network and WiBro.

For example, when the network environment is degraded to 50 kbps in the adaptive streaming apparatus 300 that has streamed the media at 100 kbps through the Wi-Fi connection, 50 kbps is streamed using the existing Wi-Fi communication network and the remaining 50 kbps is streamed simultaneously through the LTE network Although the environment is bad, it can maintain a transmission rate of 100kbps.

As described above, according to the present invention, by comparing the current transmission rate with the changed network transmission rate, the transmission rate is increased and decreased, respectively, and the corresponding transmission rate is selected to provide seamless data, There is an advantage that the user can minimize inconvenience due to frequent change of the transmission rate.

Meanwhile, the adaptive streaming method according to the embodiment of the present invention can be implemented in a computer system or recorded on a recording medium. 4, a computer system includes at least one processor 421, a memory 423, a user input device 426, a data communication bus 422, a user output device 427, And may include a storage 428. Each of the above-described components performs data communication via the data communication bus 422. [

The computer system may further include a network interface 429 coupled to the network. The processor 421 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in the memory 423 and / or the storage 428.

The memory 423 and the storage 428 may include various forms of volatile or non-volatile storage media. For example, the memory 423 may include a ROM 424 and a RAM 425.

Therefore, the adaptive streaming method according to the embodiment of the present invention can be implemented in a computer-executable method. When the adaptive streaming method according to an embodiment of the present invention is performed in a computer device, computer-readable instructions can perform the recognition method according to the present invention.

Meanwhile, the above-described adaptive streaming method according to the present invention can be implemented as a computer-readable code on a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording media storing data that can be decoded by a computer system. For example, there may be a ROM (Read Only Memory), a RAM (Random Access Memory), a magnetic tape, a magnetic disk, a flash memory, an optical data storage device and the like. The computer-readable recording medium may also be distributed and executed in a computer system connected to a computer network and stored and executed as a code that can be read in a distributed manner.

While the present invention has been described in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the above-described embodiments. Those skilled in the art will appreciate that various modifications, Of course, this is possible. Accordingly, the scope of protection of the present invention should not be limited to the above-described embodiments, but should be determined by the description of the following claims.

300: Adaptive streaming apparatus 310: Data receiving unit
320: control unit 330: data request unit

Claims

Comparing a transmission rate of the segment being received with a transmission rate of the network; And
If the transmission rate of the network is higher than the transmission rate of the next segment,
Determining a transmission rate of the next segment to be received in a second method different from the first method when the transmission rate of the segment being received is higher as a result of the comparison;
And an adaptive streaming service method.

The method of claim 1,
Obtaining an absolute value of a difference value between a transmission rate of the network and a transmission rate of the segment being received,
If the absolute value is less than or equal to a preset threshold value, a value equal to a transmission rate of the segment being received is determined as a transmission rate of the next segment to be received,
Determining a transmission rate of the segment being received and an average value of a transmission rate of the network as a transmission rate of the next segment to be received if the difference value is greater than a preset threshold value
Adaptive streaming service method.

The method of claim 1,
Obtaining an absolute value of a difference value between a transmission rate of the network and a transmission rate of the segment being received,
If the absolute value is less than or equal to a preset threshold value, a value equal to a transmission rate of the segment being received is determined as a transmission rate of the next segment to be received,
Determining an increase value by dividing the absolute value by a predetermined number of times if the absolute value is greater than a preset threshold value and adding the increase value to the transmission rate of the segment being received for each step, And repeating the step of adding the increase value in each step until the data rate of the next segment to be received is equal to the data rate of the network
Adaptive streaming service method.

2. The method of claim 1,
Obtaining an absolute value of a difference value between a transmission rate of the network and a transmission rate of the segment being received,
If the absolute value is greater than or equal to a predetermined threshold value, determines the same value as the transmission rate of the network as the transmission rate of the segment to be received next,
Determining a transmission rate of the next segment to be received as a data rate of the network if the absolute value is smaller than a preset threshold value, Playing media at the rate of the segment being received
Adaptive streaming service method.

An adaptive streaming device comprising at least one processor, the processor comprising:
A controller for comparing a transmission rate of a segment being received with a transmission rate of the network to determine a transmission rate of a segment to be received next;
A data request unit for requesting the data server to transmit the next segment to be received at a data rate determined by the controller; And
A data receiving unit for receiving data of the segment at a data rate determined by the control unit;
, Wherein the control unit
Comparing a transmission rate of the segment being received with a transmission rate of the network; And
If the transmission rate of the network is higher than the transmission rate of the next segment,
Determining a transmission rate of the next segment to be received in a second method different from the first method when the transmission rate of the segment being received is higher as a result of the comparison;
To determine a transmission rate of the next segment to be received
An adaptive streaming device.

6. The method of claim 5,
Obtaining an absolute value of a difference value between a transmission rate of the network and a transmission rate of the segment being received,
If the absolute value is less than or equal to a preset threshold value, a value equal to a transmission rate of the segment being received is determined as a transmission rate of the next segment to be received,
Determining a transmission rate of the segment being received and an average value of a transmission rate of the network as a transmission rate of the next segment to be received if the difference value is greater than a preset threshold value
Adaptive streaming method.

6. The method of claim 5,
Obtaining an absolute value of a difference value between a transmission rate of the network and a transmission rate of the segment being received,
If the absolute value is less than or equal to a preset threshold value, a value equal to a transmission rate of the segment being received is determined as a transmission rate of the next segment to be received,
Determining an increase value by dividing the absolute value by a predetermined number of times if the absolute value is greater than a preset threshold value and adding the increase value to the transmission rate of the segment being received for each step, And repeating the step of adding the increase value in each step until the data rate of the next segment to be received is equal to the data rate of the network
An adaptive streaming device.

6. The method of claim 5,
Obtaining an absolute value of a difference value between a transmission rate of the network and a transmission rate of the segment being received,
If the absolute value is greater than or equal to a predetermined threshold value, determines the same value as the transmission rate of the network as the transmission rate of the segment to be received next,
Determining a transmission rate of the next segment to be received as a data rate of the network if the absolute value is smaller than a preset threshold value, Playing media at the rate of the segment being received
An adaptive streaming service device.