JP2013526204A - Efficient playback apparatus and method for live content - Google Patents

Abstract

  A method for processing digital broadcast live content according to an embodiment of the present invention includes a step of transmitting and updating information associated with content to a client in a server, and acquiring a segment of content that can be played back in real time by the client Storing information associated with past contents, retrieving information associated with past contents, retrieving segments of reproducible content, and client when a user requests past contents Confirming whether or not the client is reproducible using the playlist, and notifying the user of this.

Description

  The present invention relates to a method for processing live content in a digital broadcasting system, and more particularly to a method for acquiring a playlist to which a client can connect when the client receives live streaming from a server using an HTTP adaptive streaming method.

  In order to transfer content to the client in accordance with changes in user equipment or transfer bandwidth, related information such as time and bandwidth related to the content segment is transferred to the client in advance and selected by the client. The file used to transfer the content information is referred to as a multimedia presentation description (MPD) file. In order to transfer multimedia suitable for an ever-changing environment, the MPD file transferred in advance from the server to the client needs to be updated over time. In particular, when live broadcast is transferred in real time, if live content is generated, the information of the MPD file also needs to be changed, so an update procedure is necessary.

FIG. 1 is a diagram illustrating an operation of a server that processes a conventional live content.
Referring to FIG. 1, when the server receives a request for transferring content whose broadcast time has passed from the client in step 111, in step 113, the server determines whether the portion of the content can be used (ie, stored in the server). Is confirmed). At this time, if the content is available in the step 113, the server transfers the content requested to the client in the step 115, otherwise transfers an error message to the client in the step 117. To do.

  As described above, conventionally, since it is not known whether or not the content requested by the client is content that can be played at the present time, the client makes a request for the time being and the content that the server can provide If it is a segment, it was provided, otherwise a rejection message was forwarded. However, the above conventional content processing method causes wasteful use of resources, and delays in content reproduction occur for the user, making it impossible to provide content efficiently.

When live content is processed in a digital broadcasting system, a playlist to which a client can connect is generated when live streaming is received from a server by the HTTP adaptive streaming method. That is, embodiments of the present invention present a method that allows a client to obtain a list of segments of content that can be played at the current time using MPD received in a live broadcast continuous broadcast. .
Then, the client guides the client not to request an unreproducible segment by displaying a playlist that is currently reproducible to the user.

  In another embodiment of the present invention, when a server-side content provider updates an MPD during live streaming, a segment list including an available segment from the segment list of the new MPD and the previous MPD. And provide the generated list to the client.

  A method of processing content in a server according to an embodiment of the present invention includes the steps of generating a multimedia presentation description (MPD) and transferring the MPD to a client, A combined segment list including the previous MPD segment list is included when the sum of the time buffer buffer depth of the previous MPD and the previous MPD segment period is greater than the availabilityStarttime of the section after the MPD NOW And

  A method of processing content in a client according to another embodiment of the present invention includes: receiving a multimedia presentation description (MPD); and summing a previous Buffer's timed Buffer Depth and a previous MPD segment period. Generating a segment combination list including a segment list of the previous MPD when it is larger than the availability Starttime of the section after the NOW of the MPD.

  According to still another embodiment of the present invention, a content processing server apparatus for processing content provided to a client includes an MPD storage unit for storing a previous multimedia presentation description (MPD), and an MPD. A user list acquisition unit for generating the MPD, and when the sum of the time buffer Buffer Depth of the previous MPD and the segment period of the previous MPD is greater than the availabilityStarttime of the section after the NOW of the MPD, the MPD It includes a combined segment list including a segment list of MPD.

  A content processing client device according to still another embodiment of the present invention includes an MPD storage unit for storing a previous multimedia presentation description (MPD), and a user list acquisition unit for generating an MPD. The MPD is a combined segment including the previous MPD segment list when the sum of the previous Buffer's timed BufferDepth and the previous MPD's segment period is greater than the availabilityStarttime of the section after the MPD's NOW. It includes a list.

  According to still another embodiment of the present invention, there is provided a method of operating a content processing system, in which a server generates an MPD, and includes a previous multimedia presentation description (MPD) timedBufferDepth and a previous MPD segment period. Generating an MPD including a combined segment list including a segment list of the previous MPD, if the sum of and the sum is greater than the availabilityStarttime of the section after the NOW of the MPD, and forwarding the MPD to the client And a step of storing a segment list including the current MPD as a playlist, and a segment of the requested content for playback when playback is requested. Determining whether or not the playlist is in the playlist, and if the segment of the content requested to be played is in the playlist, the content requested to be played back by the server in response to the playback request. And receiving the content requested to be reproduced from the server and reproducing the content.

  In a digital broadcasting system including a server and a client, when a content reproduction request from the client is input by the user, if the content exists in the playlist, the content received by requesting the content providing server is received by the user. Otherwise, an error message is forwarded to the user. Accordingly, it is possible to omit an unnecessary content transfer request operation when processing live content in the digital broadcasting system according to the embodiment of the present invention, and to efficiently use resources. In addition, the transfer procedure can be performed efficiently, and there is an advantage that there is no delay in content reproduction.

It is a figure which shows operation | movement of the server for the reproduction | regeneration of live content in the conventional digital broadcasting system. It is a figure for demonstrating the concept of time used in embodiment of this invention. It is a figure which shows operation | movement of the client which concerns on embodiment of this invention. It is a figure which shows the structure of the client which concerns on embodiment of this invention. It is a figure which shows the operation | movement procedure between the client and server which concern on embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same components are denoted by the same reference numerals as much as possible.
Further, in the following description, specific characteristic items such as names of individuals defined in OIPF (Open IPTV Forum) are disclosed. This is for a further general understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be practiced without these specific matters. In describing the present invention, if it is recognized that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted.

  In the detailed description to be described later, representative embodiments of the present invention for achieving the above-described technical problem are presented. For convenience of explanation of the present invention, the same names as those of individuals defined in OIPF (Open IPTV Forum) are used. However, these standards and names limit the scope of the present invention. Rather, it should be understood that the present invention is applicable to systems with similar technical background.

  Recently, with the increasing use of online content, the importance of smooth transfer of content has been taken up. As a result, adaptive streaming technology that changes the bit rate of content according to changes in available transfer bandwidth and user device performance has attracted attention. The user terminal selects and plays content units (that is, segments) finely divided based on the HTTP protocol according to the situation, and at this time, the transfer that enables the user terminal to use the content without delay or interruption phenomenon. Technology is discussed in several standards bodies.

  The first embodiment of the present invention relates to an apparatus and a method for acquiring a playlist to which a client can connect when the client receives live streaming from a server using an HTTP adaptive streaming method. In addition, the second embodiment of the present invention relates to an apparatus and method for generating a connectable playlist and transferring it to the client when the server transfers live streaming to the client using the HTTP adaptive streaming method.

  The digital broadcast live content processing method according to the first embodiment of the present invention will be described. The server delivers information associated with the content to the client and updates it. Next, the client acquires a segment of content that can be played back in real time, stores information linked to the previous (past) content, and searches and plays back the information linked to the previous content. A segment of a content is taken out and a playlist including the segment is generated. Then, when the user requests the previous content using the playlist, it is confirmed whether or not the client can reproduce the content, and this is notified to the user. In addition, when a client processes live content in a broadcasting system including a content transfer server and a content providing server, when the client receives an updated MPD file (ie, a current MPD file) from the content transfer server, A segment list is extracted from the current MPD file and the current MPD file to generate a playlist. When content playback is requested by the user, the client requests and receives the requested content from the content providing server if the requested content exists in the playlist, and provides the content to the user. If not (ie, if the content is not in the playlist), an error message is forwarded to the user without requesting it from the content providing server.

  At this time, the client may perform a playlist generation step, and then provide the generated playlist to the user and guide the user to request content existing in the playlist. The client may request the client to transfer a playlist before requesting content reproduction, and the client may pass the playlist to the user to request content that can be reproduced by the user. Furthermore, in the second embodiment of the present invention, when a content provider updates the MPD during live streaming, the content provider uses the new MPD (ie, the current MPD) and the segment list of the previous MPD. Generate a playlist containing possible segments and transfer it to the client.

FIG. 2 is a diagram for explaining the concept of time used in the embodiment of the present invention. The terminology relating to time used in the present invention shown in FIG. 2 follows the standard document of 3GPP.
In FIG. 2, “NOW” means a time during which the user currently views live content. “TimeShiftBufferdepth” means time for buffering and storing a past part of the live content in the content storage location of the server. Here, each MPD file may have a timeShiftBufferdepth of a different size. “Segment period” means the length of time of one piece of content (segment). “CheckTime” means a time for the client to send an MPD file request message to the service provider in order to update the MPD file. “AvailabilityStartTime” means the time when the MPD file is valid.

  FIG. 3 is a diagram illustrating the operation of the client according to the embodiment of the present invention. In FIG. 3, the client obtains a list of segments connectable at the current time point based on the information of the MPD file. That is, in the first embodiment of the present invention, the client updates the playlist using the MPD file in the live streaming continuous broadcast, and the list of content segments that the client can play at the current time Present how to get. Referring to FIG. 3, when the check time is reached, in step 311, the client first determines the time buffer buffer depth value of the MPD file (previous MPD file) before the MPD file corresponding to the current content segment and the segment of the previous MPD file. It is checked whether or not the sum with the period is larger than the value obtained by subtracting the availabilityStartTime of the segment of the current content from the current time. At this time, in the step 311, if ([timeshiftbufferdepth in the previous MPD + segment period in the previous MPD] is larger than [NOW-availabilityStartTime in the current MPD], the client proceeds to the step 313 and moves to the previous MPD file. The segment list is extracted by combining a part of the segment and the segment of the current MPD file, and [timeshiftbufferdepth + segment period in the previous MPD] is set to [NOW-availabilityStartTime in the current MPD] in step 311. If not, the client sends a step 315 Oite, take out the segment list with the current MPD.

  Here, the operation of step 313 will be described. If it is confirmed in step 311 that [timeshiftbufferdepth in previous MPD + segment period in previous MPD] is larger than [NOW-availabilityStartTime in current MPD] The client performs a step of extracting a currently reproducible content segment from the segments belonging to the previous MPD. That is, a list of reproducible segments is acquired between the time obtained by subtracting the value of the time shift buffer depth of the previous MPD from the current time NOW and the value of the segment period in the previous MPD and CheckTime. In addition, the client obtains a list of segments that can be reproduced at the current time among the segments belonging to the current MPD. That is, a list of segments that can be reproduced between the availabilityStartTime in the current MPD and the current time NOW is acquired. For this reason, [NOW-timeShiftBufferDepth in previous MPD-segment period in previous MPD; CheckTime in previous MPD] and segment of previous MPD that can be played during [MP] and current MPD that can be played back in [availabilityStartTime; NOW] By combining the list of segments, a playlist of segments that can be reproduced at the current time NOW is generated.

  The client stores the playlist acquired in this way. After this, when the user requests playback of a segment at a past time of the content, the client requests the current segment from the server if the requested content is included in the playlist. Otherwise, an error message is displayed to the user without requesting the content providing server to transfer the segment. It should be noted that the user may not be requested for content that cannot be played back by notifying the user in advance of the time when playback is possible.

FIG. 4 is a diagram illustrating a configuration of a server or a client according to the embodiment of the present invention.
Referring to FIG. 4, the previous MPD storage 410 stores the previous MPD (previous MPD), not the MPD for the currently playing content segment. The playlist retrieval module 420 performs a function of requesting the server from the server at the current time point to obtain a list of reproducible segments. The playlist retrieval module 420 can generate a playlist while performing the procedure shown in FIG. The adaptive algorithm operation unit 430 performs an operation in which the client acquires an appropriate content segment according to the bandwidth and the capability of the device. The playlist confirmation unit 440 performs a function of confirming whether the segment requested by the user is included in the playlist acquired by the current playlist retrieval module.

FIG. 5 is a diagram illustrating a procedure of an operation between the client and the server according to the embodiment of the present invention.
Referring to FIG. 5, the content providing server 505 is a server belonging to a service provider that plays a role of generating MPD for providing content to the client 503 and transmitting and receiving messages. First, when the user 501 requests content viewing in step 511, the client 503 transfers an adaptive streaming content request message to the content providing server in step 513. Next, the content providing server 505 constructs an initial MPD file (MPD # 1 file) for supporting adaptive streaming of content in step 515, and is generated to transfer the content in step 517. The first MPD file is transferred to the client 503. Next, in step 519, the client that has received the MPD file connects each segment to the URL of the live content providing server 507 that provides live broadcast streaming (ie, connects to the URL of the file to request content). Accordingly, the live content providing server 507 transfers the segment requested by the client 503 to the client 503 in step 521. Next, the user 501 can view the content requested in step 523.

  At this time, when the service provider has to update the MPD, the content providing server 505 determines in step 525 that the next MPD file (here, MPD #) is used to support adaptive streaming of the content. 2 file). In step 527, the client 503 stores the previous MPD file (which may be an MPD # 1 file here), and in step 529, the CheckTime of the first MPD (MPD # 1, previous MPD) is stored. In step 531, the client 503 transfers an MPD update request message to the content providing server 505 for MPD update. Next, the content providing server 505 transfers the second MPD file (MPD # 2 file, current MPD file) to the client 503 in step 533.

Next, in step 535, the client 503 generates a playlist that can be played back while performing the procedure shown in FIG. At this time, the previous MPD may be MPD # 1, and the current MPD may be MPD # 2.
At this time, if the user 501 requests content playback at a past time in step 537, the client 503 checks in step 539 whether the content segment at the time requested by the user is currently in the playlist. At this time, if the content requested by the user 504 is in the playlist generated in step 535, the client 503 requests the segment from the live content providing server 507 in step 541, and the live content providing server 507 In step 543, this is transferred to the client 503. Therefore, the user can view the content at the past time requested in step 545. If the segment requested by the user is not currently included in the playlist, the client 503 transmits an error message to the user 501 in step 551.

  As described above, when the client 503 receives a content playback request at a past time from the user in a state where the playlist is generated and stored, the client 503 checks whether the requested content exists in the playlist. At this time, if the content exists in the playlist, the client 503 performs control so that the user 501 can view the content by requesting and receiving the content from the live content providing server 507 while executing step 540. If not present in the playlist, the client 503 transfers an error message to the user in step 551 without performing an operation of requesting the content from the live content providing server 507. For this reason, the content processing method according to the embodiment of the present invention does not request unnecessary content, so that resources are not wasted and content reproduction is not delayed for the user. It can be carried out.

  Further, the client 503 may guide the user 501 not to request a segment that cannot be reproduced by displaying a playlist that can be reproduced at present. That is, the client 503 may display the playlist so that the user 501 can check it after generating the playlist in step 535. In this case, the user 501 may request only a reproducible segment while confirming the playlist when requesting content reproduction. Alternatively, as another method, the user requests a playlist from the client 503 when requesting content playback at a past time, and confirms the playlist responded by the client 503 to efficiently request the content. Also good.

A second embodiment of the present invention will be described.
In the second embodiment of the present invention, when the server generates a new MPD to update the MPD, it includes a list of segments that can still be connected among the segments managed by the previous MPD (ie, a playlist). A new MPD is generated. Then, the server transfers and updates the new MPD including the generated playlist to the client. In the second embodiment of the present invention, the content providing server 505 can perform the operation shown in FIG. When the content provider updates the MPD in the case of live streaming, as described above, the new MPD needs to include every available segment, including the previous MPD segment. If the sum of the time shift buffer depth of the previous MPD and the segment period is greater than NOW minus the availabilityStartTime in the current MPD, the new MPD is the sum of the media segment and the start time of the period (period). Includes any media segment that exists between the current MPD and the previous MPD NOW-timeshiftBufferDepth-duration and CheckTime.

  Alternatively, if the sum of the time shift buffer depth of the previous MPD and the segment period is larger than the value obtained by subtracting the current MPD's availabilityStartTime from NOW, the playlist has the sum of the media segment and the start time of the period (period). , Including any media segment that exists between the current MPD and the previous MPD NOW-timeshiftBufferDepth-duration and CheckTime.

  Alternatively, if the sum of the time shift buffer depth of the previous MPD and the segment period is larger than the value obtained by subtracting the current MPD's availabilityStartTime from NOW, the new MPD is the sum of the media segment and the disclosure time of the period (period). Is the smallest value of the current MPD and the previous MPD NOW-timeshiftBufferDepth-duration and CheckTime, NOW, availabilityStarttime + mediaPresentationDuration [min (CheckTime, NOW, AvailabilityDate]] Both the instrument including.

410 MPD storage before 420 420 playlist retrieval module 430 adaptive algorithm operation unit 440 playlist confirmation unit 501 user 503 client 505 content providing server 507 live broadcast content providing server (with buffer)

Claims (15)

In the content processing method on the server,
Generating a multimedia presentation description (MPD);
Transferring the MPD to a client;
Including
The MPD is a combined segment list including the previous MPD segment list when the sum of the previous Buffer's timed BufferDepth and the previous MPD's segment period is greater than the availabilityStarttime of the section after the MPD's NOW. A method comprising the steps of: Generating the MPD comprises:
The MPD's availabilityStarttime and the current MPD segment existing in the NOW interval (NOW-previous MPD timeShiftBufferDeph-previous MPD segment duration) and the previous MPD segment existing in the checktime interval are combined. The method of claim 1 including a segment list to be processed.   Generating an MPD including a segment list of the current MPD if the sum of the previous MPD's timeBufferBufferDeph and the segment period is less than or equal to NOW minus the current MPD's availabilityStarttime The method of claim 1 further comprising: In the content processing method on the client,
Receiving a multimedia presentation description (MPD);
Generating a segment combination list including the previous MPD segment list when the sum of the previous BufferTime Depth of the previous MPD and the previous MPD segment period is greater than the availabilityStarttime of the section after the MPD NOW;
A method comprising the steps of: The step of generating a segment combination list including the segment list includes:
The MPD availabilityStarttime and the current MPD segment existing in the NOW interval (NOW-previous MPD timeBufferBuffer-previous MPD segment duration) and the previous MPD segment existing in the checktime interval are combined. The method of claim 4, further comprising a segment list.   Generating an MPD including a segment list of the current MPD if the sum of the previous MPD's timeBufferBufferDeph and the segment period is less than or equal to NOW minus the current MPD's availabilityStarttime The method of claim 4, further comprising: Determining whether a segment of the requested content for playback is in the list when playback is requested;
When the segment of the content requested to be played is in the list, the server requests the playback requested content in response to the playback request, and receives the playback requested content from the server. Step to play and
The method of claim 4, further comprising: Providing a user list when there is a request to play content,
When there is a playback request from a user in the user list, the server requests the playback requested content in response to the playback request, and receives the playback requested content from the server for playback. And steps to
The method of claim 4, further comprising: In a content processing server device for processing content provided to a client,
An MPD storage for storing a previous multimedia presentation description (MPD);
A user list acquisition unit for generating an MPD;
With
The MPD is a combined segment list including the previous MPD segment list when the sum of the previous Buffer's timed BufferDepth and the previous MPD's segment period is greater than the availabilityStarttime of the section after the MPD's NOW. A server device comprising:   The combined segment list exists within the current MPD segment in the MPD availabilityStarttime and NOW sections, and the current MPD segment (NOW-previous MPD timeBufferBuffer-previous MPD segment period) and checktime sections. The server apparatus according to claim 9, wherein the server apparatus is combined with a previous MPD segment.   The user list acquisition unit calculates the segment list of the current MPD when the sum of the previous Buffer PD and the segment period is equal to or smaller than the value obtained by subtracting the current MPD availabilityStarttime from NOW. The server apparatus according to claim 9, wherein the server apparatus generates an MPD including the server. In the content processing client device,
An MPD storage for storing a previous multimedia presentation description (MPD);
A user list acquisition unit for generating an MPD;
With
The MPD is a combined segment list including the previous MPD segment list when the sum of the previous Buffer's timed BufferDepth and the previous MPD's segment period is greater than the availabilityStarttime of the section after the MPD's NOW. A client device comprising:   The combined segment list exists within the current MPD segment in the MPD availabilityStarttime and NOW sections, and the current MPD segment (NOW-previous MPD timeBufferBuffer-previous MPD segment period) and checktime sections. The client apparatus according to claim 12, wherein a previous MPD segment is combined.   The user list acquisition unit calculates the segment list of the current MPD when the sum of the previous Buffer PD and the segment period is equal to or smaller than the value obtained by subtracting the current MPD availabilityStarttime from NOW. 13. The client device according to claim 12, wherein the client device generates an MPD including the client device. In the operation method of the content processing system,
When the server generates an MPD, and the sum of the previous Buffer Presentation Depth of Multimedia Presentation Description (MPD) and the segment period of the previous MPD is greater than the availabilityStarttime of the section after the NOW of the MPD Generating an MPD including a combined segment list including a segment list of the previous MPD; and
Transferring the MPD to a client;
A client storing a segment list including the current MPD as a playlist;
Determining whether a segment of the content requested to be played is in the playlist when playback is requested;
If the play requested content segment is in the playlist, the server requests the play requested content in response to the play request, and sends the play requested content from the server. Receiving and playing, and
A method comprising the steps of:

Images