KR101397183B1 - Method and apparatus for managing playlist file in streaming service - Google Patents

Abstract

For a live streaming service, a playlist file is requested to and received from a streaming server. Update of the playlist file is determined via the streaming server based on the first image file name piece or the last image file name piece among the playlists included in the received playlist file. The received playlist file is changed based on the determination result.

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for managing a playlist file in a streaming service,

The present invention relates to a streaming service, and more particularly, to a method and apparatus for requesting and managing a playlist file in a live streaming service.

Recently, streaming service which plays multimedia data in real time through the Internet has been activated. In recent years, it has been used not only a traditional server-oriented protocol such as RTMP (real time messaging protocol) / RTSP (real time streaming protocol) streaming service is provided using hyper text transfer protocol. Progressive download method and HTTP live streaming (hereinafter referred to as HLS) are widely used as a method of providing a streaming service using the standard HTTP protocol.

The HLS scheme fragment a media file into a file having a small length (for example, MPEG-2 Transport Stream file) of 10 seconds (typically, 5 seconds to 15 seconds) Lt; / RTI > file to the client. The playlist file uses an M3U8 (HLS2) file that uses SMIL (Synchronized Multimedia Integration Language) syntax, which is a type of XML (Extensible Markup Language). Accordingly, the file name format is ".M3U8" or ".M3U". Here, the ".M3U" file is used for audio-only content.

The file fragments, that is, image fragment files, are structured in the MPEG2-TS format and the extension of the file is "ts". The names of the files indicate sequential order, so they are generated so that the next file name can be inferred. It mainly uses numbers in decimal form, but may also be expressed in other notation. The playlist file may provide tags that can be set with respect to the playback order of the video clip files and various playback related functions with the extension function.

The client downloads the playlist file from the server using the HTTP protocol, downloads the specified image fragment files from the playlist file, and sequentially plays back the files sequentially.

In the HLS service, a playlist file is usually sent to the client with a play order for three or more image slice files. If the playback starts from the end of the third video clip file in the file list of the newly delivered playlist file, the client newly requests the playlist file. In addition, if the client receives a playlist file from the server and finds an updated list, the client waits for the length of the last image fragment file of the minimum playlist, and then requests files corresponding to the updated playlist. If the playlist has not been updated, it waits 0.5 times the target length and then requests the playlist file again.

On the other hand, the live stream time shifting represents a technique for storing media streaming transmitted through a network in real time and pausing and searching for a real time broadcast like a video broadcast (VOD). In other words, the technique of storing or recording broadcasts on the network is called "nDVR ". As a specific example of live stream time shifting, if you want to watch the news that was broadcast 20 minutes ago, you can move the playback position to the position 20 minutes ago and view the news from that point.

However, there is a disadvantage in that the size of the playlist file increases as the range of the live stream time shifting function is increased. In addition, in the case of contents to be broadcasted in real-time, because it is a real-time broadcast, a newly updated playlist file is requested and received at a predetermined time interval. Especially, as the range of the past time when the time shifting service is available increases, the transmission amount of the play list file increases exponentially. For example, if it is desired to provide a time shifting service with a range of the past time as 24 hours, it is difficult to provide a service because a large network cost is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for managing a playlist file that can reduce the amount of data to be transmitted when a time-shifting function is used in a live streaming service.

According to another aspect of the present invention, there is provided a method of managing a playlist file by providing a live streaming service, the method comprising: requesting and receiving a playlist file by a streaming server; A first requesting step of requesting a corresponding video fragment file while transmitting the next video fragment file name based on the last video fragment file name among the play lists included in the received play list file to the streaming server; A second requesting step of requesting a corresponding image fragment file while transmitting a first image fragment file name to the streaming server; Receiving a response corresponding to the first requesting step or the second requesting step from the streaming server; Adding, in response to the request of the first requesting step, a video piece file name of the next order to the received playlist file when a response indicating the existence of a corresponding video fragment file is received; And changing a playback order in the received playlist file when a response indicating that a corresponding video fragment file does not exist is received in response to the request of the second requesting step.

If a response indicating that a corresponding file does not exist is received in response to the request of the first requesting step, the first requesting step is repeatedly performed, and a response is made in response to the request of the second requesting step The second requesting step may be repeatedly performed if a response is received indicating that a file exists.

An indicator indicating a maximum playback time of each file, and a directive indicating a serial number of a file to be played back first. In this case, the step of changing the reproduction order may increase the directive indicating the serial number included in the playlist file by +1.

The step of changing the playback order may further include deleting the first image fragment file name from the playlist file.

Meanwhile, the first requesting step and the second requesting step may be performed in parallel.

In addition, the first requesting step and the second requesting step may perform a request using a HEAD request method that receives only a hypertext transfer protocol (HTTP) header response without receiving an actual file.

According to the embodiment of the present invention, in a live streaming (HLS) service, a process of requesting and receiving a playlist file is not repeated, Through the changing process, it is possible to reduce the amount of transmission generated according to the request and transmission of the playlist file.

In particular, even when the time shifting function is provided, the request and transmission of the playlist file including the vast playlist are not repeatedly performed, so that the amount of file transfer can be significantly reduced. In a streaming service that provides time shifting, the amount of playlist file transfer can be maintained and reduced to the level used in normal live broadcasting, regardless of the time-shifting time range. Therefore, the network cost is reduced, and the service providing the time shifting function can be smoothly provided.

1 is a diagram illustrating transmission / reception of a file in an HTTP (Hypertext Transfer Protocol) live streaming service.
2 is a diagram illustrating a structure of a metadata file according to an embodiment of the present invention.
FIG. 3 is an exemplary view showing a general metadata file in a live streaming service using the HLS protocol, and FIG. 4 is an exemplary view showing a metadata file in a live streaming service supporting time shifting.
5 is a diagram illustrating a structure of a playlist file management apparatus according to an embodiment of the present invention.
6 is a flowchart illustrating a method of managing a playlist file in a live streaming service supporting time shifting according to an embodiment of the present invention.
7 is an exemplary view illustrating a file request and a response according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

Hereinafter, a method and apparatus for managing a playlist file in a streaming service according to an embodiment of the present invention will be described with reference to the drawings.

1 is a diagram showing file transmission / reception in HTTP (Hypertext Transfer Protocol) live streaming (hereinafter referred to as HLS) service.

When the client 1 receives a live streaming service based on the HLS from the streaming server 2, the streaming server 2 encodes the video data to be served and segments the encoded video data into a plurality of video fragment files And generates metadata that can access the generated image fragment files. The image fragment files are provided in the form of a transport stream (TS). The metadata of the image fragment files provide information about which files should be reproduced to the client 1, that is, a reproduction file list. A metadata file including a playback file list is provided to the client 1 in the form of an M3U8 file. The client 1 requests files to be played back on the streaming server 2 based on the play file list included in the meta data file, and the streaming server 2 provides corresponding video file files in response to the request.

The metadata file (M3U8 file), which is the information on the moving picture to be played back, transmitted from the streaming server 2 to the client 1 includes the names of video fragment files, i.e. TS files, And may comprise a non-negative integer that increases sequentially.

2 is a diagram illustrating a structure of a metadata file according to an embodiment of the present invention.

As shown in FIG. 2, the metadata file, that is, the playlist file, generally includes a directive (#EXTM3U) indicating that the file uses the M3U8 format, a maximum playback time of each file listed in the list file, A directive (# EXT-X-MEDIA-SEQUENCE) indicating a sequence number of a file to be played back first, a directive (#EXTINF) indicating a playback time of a TS file next to the directive .

FIG. 3 is an exemplary view showing a general metadata file in a live streaming service using the HLS protocol, and FIG. 4 is an exemplary view showing a metadata file in a live streaming service supporting time shifting.

In a live stringing service using the HLS protocol, the playlist file typically includes three video fragment files (e.g., 2680.ts, 2681.ts, 2682.ts), as in FIG. 3, (G01) indicates "10 seconds ".

Unlike a playlist file in this general HLS live streaming service, a playlist file in a streaming service that provides time shifting functionality has more image fragment files. .

For example, a time-shifting function is added to a live streaming service using a playlist file in which the target length is "10 seconds " and the length of each video fragment file is 10 seconds, , A playlist file as shown in Fig. 4 is obtained.

As shown in Fig. 4, the playlist file includes a plurality of video fragment files. The number (L01, L02) at which the video fragment files to be reproduced start is "2680" and the end number of the video fragment files is "11132" (L03). That is, a total of 8642 pieces of image fragment files to be played back include a list of files about 2,800 times larger than a playlist file (a file of FIG. 3) for a general live streaming service.

Due to the nature of the HLS service, newly created playlist files are requested and obtained at a certain time interval (for example, 0.5 times the length of the final image fragment file or the target length in the playlist file) when a new image fragment file is created. This results in an additional amount of traffic that has not been generated in conventional live services. In the HLS service that does not provide time shifting, a lot of traffic is generated in response to file request and acquisition. As described above, in the HLS service providing time shifting, as the playlist file includes a large number of file lists, Traffic due to requests and acquisitions can be exponentially increased. That is, according to provision of time shifting, the size of the playlist file increases as the range that can be turned to the past viewpoint increases, and since the live play is broadcast, requesting and acquiring a newly updated playlist file at a predetermined time interval, .

For example, as shown in FIG. 3, the size of the playlist file including three video fragment files is approximately 250 Bytes and the total playback time is 30 seconds. The size of the playlist file having a past play time of 24 hours according to time shifting based on the playlist file is approximately " 703 Kbytes ", approximately 24 x 60 x 60 x 250 Bytes / 30 = 720000 Bytes. When a playlist file supporting such time shifting is received every 10 to 5 seconds, traffic of about 563 Kbps to 1.10 Mbps is required. Currently, the transmission size of image is 600Kbps ~ 2Mbps. Based on this, it is necessary to transmit 1.3 to 3.2 times the minimum current transmission size. However, the above calculation is based on a simple playlist file. In case of providing a live streaming service having a time shifting when a real service is provided, a much larger transmission amount is required for transmitting / receiving the playlist file.

Accordingly, an embodiment of the present invention provides an apparatus and method for efficiently requesting and acquiring a playlist file in a live streaming service providing a time shifting function.

In the following embodiments, the names of the image fragment files (TS files) included in the playlist file are sequentially increased. However, the present invention is not limited thereto.

5 is a diagram illustrating a structure of a playlist file management apparatus according to an embodiment of the present invention.

5, the playlist file management apparatus 100 according to the embodiment of the present invention includes a playlist file acquisition unit 110, a video fragment file monitoring unit 120, a playlist file management unit 130, And a playlist file transfer unit 140. [

The playlist file obtaining unit 110 requests the streaming server 2 to play the playlist file and obtains the corresponding playlist file. The playlist file has a structure as shown in FIG. 4, and includes a playlist composed of the names of video fragment files to be played, that is, image fragment file names.

The video sculpting file monitoring unit 120 monitors the video sculpting files included in the acquired playlist file and identifies the video sculpting filename to be played back first from the video sculpting filenames included in the playlist file and the video sculpting filename to be played last . In addition, the image sculpting file is monitored in parallel based on the image sculpting filename to be reproduced first and the image sculpting filename to be reproduced last.

To this end, the video fragment file monitoring unit 120 includes a first fragment file monitoring unit 121 and a second fragment file monitoring unit 122.

The first fragment file monitoring unit 121 changes the image fragment file name to be reproduced last obtained from the playlist file to the image fragment file name corresponding to the next sequence, and outputs the changed image fragment file name to the streaming server 2) request a video fragment file to be reproduced.

The second fragment file monitoring unit 122 requests a video fragment file to be reproduced by the streaming server 2 with the first video fragment file name to be reproduced first obtained from the play list file.

The first and second fragment file monitoring units 121 and 122 can use a HEAD request method when requesting a video fragment file to be played back by the streaming server 2 as a file name. A head request is one that receives only an HTTP header (header) response without actually receiving the file. If a head request can not be made due to the characteristics of the streaming server 2, a method of receiving only a header portion using a GET command may be used.

The first fragment file monitoring unit 121 requests the image fragment file with the image fragment file name corresponding to the next sequence of the last image fragment file name, that is, the changed image fragment file name, and then displays the file from the streaming server 2 When a response is received, the changed video image file name is added to the play list. When a response is received from the streaming server 2 that the file does not exist, the streaming server 2 repeats the operation of requesting the streaming server 2 with the same file name, that is, the changed video fragment file name.

When the second fragment file monitoring unit 122 receives a response from the streaming server 2 that the file exists, after requesting the image fragment file with the first image fragment file name, the second fragment file monitoring unit 122 re- 2) to repeat the operation of requesting the image segment file name. On the other hand, if a response is received that the file does not exist from the streaming server 2 after requesting the video fragment file with the first video fragment file name, the corresponding file name, i.e., the first video fragment file name is deleted from the play list, (# EXT-X-MEDIA-SEQUENCE) indicating the serial number of the file is incremented by a predetermined value (for example, +1).

The playlist file modification unit 130 modifies the playlist according to the monitoring results of the first and second fragmented file monitoring units 121 and 122. That is, under the control of the first fragment file monitoring unit 121, the changed image fragment file name is added to the reproduction list. (# EXT-X-MEDIA-SEQUENCE) is increased by a predetermined value (for example, +1) in accordance with the control of the first fragment file monitoring unit 122 or the second fragment file monitoring unit 122.

The playlist file transfer unit 140 provides the playlist to a playback apparatus not shown, and in particular, the playlist file modification unit 130 provides the playlist modified to the playback apparatus. Here, the playback apparatus represents a device that plays video data on the client.

The playlist file management apparatus 100 having such a structure can be implemented in a form located in the client 1. [

A method of requesting a playlist file in a live streaming service supporting time shifting according to an embodiment of the present invention will now be described based on such a structure.

6 is a flowchart illustrating a method of managing a playlist file in a live streaming service supporting time shifting according to an embodiment of the present invention.

The playlist file management device 100 transmits the acquired playlist file to a playback device (not shown) so that the video slice file included in the playlist file is played back.

Due to the nature of the live streaming service, a new playlist file is created while creating a new video slice file. In an embodiment of the present invention, when a live streaming service is provided according to the time shifting function, in order to prevent an increase in transmission amount due to frequent requests and transmission of a playlist file including a large number of file lists, , It is determined whether or not the playlist file according to the video piece file newly generated from the streaming server 2 has been changed using the first video fragment file name and the last video fragment file name among the file lists included in the play list file received by the streaming server 2 If a change has occurred, the playlist file managed without receiving the playlist file is changed, and the playback apparatus can receive and reproduce the newly created video slice file.

6, the playlist file management apparatus 100 requests the playlist file from the streaming server 2 and transmits a playlist file (for example, a playlist file File) (S100, S110).

The playlist file management apparatus 100 obtains the first video fragment file name and the last video fragment file name among the file names of the video fragments included in the obtained play list file (S120). Then, the playlist file management apparatus 100 monitors video image files being live streamed on the basis of the first video fragment file name and the last video fragment file name, modifies the play list file according to the monitoring result, and transmits the modified play list file to the playback apparatus.

Specifically, the playlist file management apparatus 100 changes the last image fragment file name to a file name corresponding to the next sequence (S130). In this case, it is assumed that the image piece file names are sequentially increasing. Therefore, when the play list file having the structure as shown in FIG. 4 is acquired, the last image piece file name "11322.ts" is incremented by one to "11323.ts" Change it.

Then, the playlist file management apparatus 100 requests the image sculpting file while transmitting the changed image sculpting filename 11323.ts to the streaming server 2 (S140). A response is received from the streaming server 2 in response to such a request.

7 is an exemplary view illustrating a file request and a response according to an embodiment of the present invention.

The playlist file management apparatus 100 transmits a head request including "11323.ts" to the streaming server 2, as in Fig. Accordingly, a response Res.1 indicating that the file corresponding to the request does not exist is received from the streaming server 2, or a response (Res. 2) indicating that the file corresponding to the request exists is received.

When receiving a response (e.g., Res.1) indicating that the file does not exist, the playlist file management apparatus 100 determines that a new video fragment file has not yet been generated and stores the same changed video fragment file name (e.g., 11323 (S150), the streaming server 2 repeatedly requests the image sculpting file.

However, if a response indicating that a file corresponding to the request exists (e.g., Res. 2) is received, the playlist file management apparatus 100 determines that a new video fragment file has been created, A modified image fragment file name (e.g., 11323.ts) is added (S160).

On the other hand, the playlist file management apparatus 100 performs surveillance operations based on the first video fragment file name while performing an operation of monitoring whether or not to generate a video fragment file based on the last video fragment file name. When the playlist file having the structure as shown in FIG. 4 is obtained, the playlist device 100 requests the video thumbnail file while transmitting the first video thumbnail file name "2680.ts" to the streaming server 2 (S170).

When a response (e.g., Res.1) indicating that the file corresponding to the request does not exist is received from the streaming server 2 in response to such a request, the corresponding file name, i.e., the first video fragment file name (e.g., 2680. ts) are deleted (S180, S190). And change the value of the directive (# EXT-X-MEDIA-SEQUENCE) indicating the serial number of the file to be played first in the playlist file to change the order of the file to be played first. That is, +1 is added to the value of the directive EXT-X-MEDIA-SEQUENCE (S200), for example. Accordingly, the playlist file is played back from "2681.ts" instead of "2680.ts".

On the other hand, when a response (e.g., Res. 2) indicating that a file corresponding to the request exists is received from the streaming server 2 in response to a request based on the first video fragment file name, It repeatedly requests the streaming server 2 to request a video fragment file based on the first video fragment file name (e.g., 2680.ts).

If the streaming server 2 determines that the playlist file has been changed in accordance with the generation of the new video segmentation file in the above manner, the streaming server 2 may not additionally receive the playlist file, To change the order of the image slice files to be played back, or to change the last image slice file name.

The playlist file management apparatus 100 delivers the changed playlist file to the playback apparatus at the request of the playback apparatus (S210).

On the other hand, the playlist file management apparatus 100 repeatedly performs the above-described steps S120 to S210 on the basis of the changed playlist file.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (6)

In a method of managing a playlist file according to a live streaming service provision,
Requesting and receiving a playlist file with a streaming server;
A first request step of requesting a corresponding image fragment file while transmitting a next image fragment file name based on a last image fragment file name among the play lists included in the received play list file to the streaming server,
A second requesting step of requesting a corresponding image fragment file while transmitting a first image fragment file name to the streaming server;
Receiving a response corresponding to the first requesting step or the second requesting step from the streaming server;
Adding, in response to the request of the first requesting step, a video piece file name of the next order to the received playlist file when a response indicating the existence of a corresponding video fragment file is received; And
Changing a playback order in the received playlist file when a response indicating that a corresponding video fragment file does not exist is received in response to the request of the second request step
/ RTI > of the playlist file. The method of claim 1, wherein
When a response indicating that a corresponding file does not exist is received in response to the request of the first request step, the first request step is repeatedly performed,
And repeating the second request step when a response indicating that a corresponding file exists is received in response to the request of the second request step. The method of claim 1, wherein
A directive indicating a maximum playback time of each file, and a directive indicating a serial number of a file to be played back first,
Wherein the step of changing the reproduction order increases the directive indicating the serial number included in the playlist file by +1. The method of claim 3, wherein
The step of changing the playback order
Further comprising deleting the first video segment file name from the playlist file. The method of claim 1, wherein
Wherein the first requesting step and the second requesting step are performed in parallel. The method of claim 1, wherein
Wherein the first requesting step and the second requesting step perform a request using a HEAD request method that receives only a hypertext transfer protocol (HTTP) header response without receiving an actual file, .

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