JP2020123765A - User terminal and program - Google Patents

Abstract

To reduce, when a user viewing a net moving image performs zapping, a latency time until viewing of another moving image starts.SOLUTION: A user terminal 1 comprises: a downloading time prediction unit 23 that when zapping is performed by a user, predicts a downloading time of a segment after moving image switching with respect to another moving image after the zapping on the basis of a previously measured downloading time; a segment-to-be-overwritten number determination unit 25 that with respect to the segment after moving image switching and on the basis of the predicted downloading time, determines locations to be overwritten (segment-to-be-overwritten numbers) in a plurality of segments before moving image switching stored in a buffer memory unit 29; a writing control unit 27 that sequentially overwrites the locations of the segment-to-be-overwritten numbers in the buffer memory unit 29 with the segment after moving image switching; and a decoder delivery control unit 28 that after delivering the segments before moving image switching from the buffer memory unit 29 to a decoder unit 14, delivers the segment after moving image switching.SELECTED DRAWING: Figure 5

Description

The present invention relates to a user terminal and a program for switching a video according to a user operation in a system for performing adaptive streaming in which a video is distributed from a server to a user terminal.

Conventionally, a user who views a television broadcast may perform zapping in order to switch to another channel. Similarly, while watching a moving image (net moving image) distributed via the Internet, the user may perform zapping in order to switch to another moving image.

In such zapping, the longer the time until another moving image is reproduced, the lower the user's quality of experience, and the more likely there is a possibility that the user will stop watching the moving image.

Generally, a net moving image is transferred from a server to a user terminal via the Internet by a method called adaptive streaming. The moving image data at this time is transferred in units called segments segmented on the time axis. The segment is a moving image file obtained by dividing the encoded moving image data into units of several seconds. For example, the time length of moving image data is various, such as 1 minute, 10 minutes, and 1 hour, and the time length of segments is also various, such as 1 second, 5 seconds, and 10 seconds.

Adaptive streaming includes, for example, the MPEG-DASH method and the HLS method. These systems have the same basic operation flow, and have the feature that even if the Internet is congested, the playback of moving images is continued as much as possible and no interruption occurs.

In order to realize this feature, the user terminal uses a buffer memory to buffer a predetermined number of segments, and then passes the segments to the decoder in order from the beginning. That is, the user terminal stores a segment of moving image data in a buffer memory by the FIFO (First-In First-Out) method, reads it from the buffer memory, and transfers it to the decoder (for example, see Non-Patent Document 1).

Further, there is also disclosed a technique of storing a segment before switching a moving image and a segment after switching the moving image in different buffer memories (for example, refer to Patent Document 1). By this technique, when the segment stored in the buffer memory can be reused, the moving image can be quickly reproduced.

The number of segments to be buffered varies, for example, 3 segments, 5 segments, etc., and the larger the number of segments, the more difficult it is to interrupt the reproduction of moving images when the Internet is congested.

However, the larger the number of buffered segments, the longer the buffering and the slower the delivery to the decoder. For this reason, the time from the user terminal requesting the server to deliver the segment to the reproduction of the moving image after the decoding process becomes long, and the user has a long waiting time for viewing.

JP, 2017-108217, A

IT glossary, e-Words, "FIFO", [online], [November 19, 2018 search], Internet <URL: http://e-words.jp/w/FIFO.html>

As described above, when the FIFO method is used for adaptive streaming buffer management, there is a problem that when a user zapping a net moving image, it is not immediately switched to another moving image and it takes time to switch. Zapping is a switching operation from a video being viewed to another video.

This is because when zapping is performed, it is necessary for the user terminal to pass all the segments of the movie that is already buffered and is being watched to the decoder, and then the segment of another movie to be watched next is passed to the decoder. Is. That is, when the zapping is performed, the switching time, that is, the waiting time until the start of viewing another moving image is determined according to the number of already-buffered segments of the moving image being viewed. The larger the number of segments of the already buffered moving image being viewed, the longer the waiting time, and the smaller the number of segments, the shorter the waiting time.

For example, if the number of buffered video segments being watched is 3 and the segment length is 1 second, the time until the next video segment to be watched is passed to the decoder is at least 3 segments×1. Seconds=3 seconds. This 3 seconds is the waiting time until the user starts viewing.

FIG. 8(1) is a diagram illustrating buffer management of adaptive streaming using the FIFO method of the related art. The segment of the moving image that is being viewed is the segment before moving images, and the segment of another moving image that is switched by zapping is the segment after switching the moving images.

It is assumed that the moving image pre-switching segments SG1 to SG5 are buffered in the buffer memory unit of the user terminal. When zapping is performed by the user in this state, another moving image request is transmitted from the user terminal to the server.

Then, the user terminal receives the segments SG6', SG7', etc. after moving image switching from the server. Then, if there is a free space in the buffer memory unit, the user terminal will buffer these moving image switched segments SG6', SG7', etc. in order as the segment next to the moving image pre-switching segment SG5.

The user terminal sequentially reads the moving image pre-switching segments SG1 to SG5 from the buffer memory unit and transfers them to the decoder. Then, after the transfer of the segments SG1 to SG5 before moving image switching is completed, the user terminal reads the segments SG6', SG7' after moving image switching from the buffer memory unit and transfers them to the decoder.

In this way, when the user performs the zapping, the passing of the buffered segments before moving image switching SG1 to SG5 is completed, and then the passing of the segments after moving image switching SG6′, SG7′ of another moving image is started. .. Therefore, the delivery time (transfer time) of the segments SG1 to SG5 before moving image switching is the switching time, that is, the waiting time until the start of viewing another moving image to be viewed next.

In other words, when the FIFO method is used for buffer management of adaptive streaming, another moving image is not immediately switched when zapping is performed. The user needs to wait for the time until the delivery of the buffered segments SG1 to SG5 before moving image switching is completed, and there is a problem that switching takes time.

Therefore, when performing adaptive streaming buffer management, it has been desired to shorten the moving image switching time associated with zapping by using a new method instead of the FIFO method.

Therefore, the present invention has been made to solve the above problems, and an object thereof is to reduce the waiting time until the start of viewing another video when a user watching an online video performs zapping. To provide possible user terminals and programs.

In order to solve the above problems, the user terminal according to claim 1 receives a moving image distributed via the Internet for each segment, buffers and reads the segment by a FIFO method, and reproduces the moving image. In the terminal, when the download time measurement unit that measures the download time of the segment and the switching operation for playing another video by the user are performed, the video in the video before the switching operation measured by the download time measurement unit Based on the download time of the segment before switching, the download time of the segment after the video switching of the different video is predicted, and the download time prediction unit that obtains the download predicted time, and the download prediction obtained by the download time prediction unit Based on time, an overwrite segment determination unit that determines the segment before moving image switching that is a target of overwriting among the plurality of segments before moving image switching that are buffered in the buffer memory, and the segment after moving image switching are sequentially received. Then, the segment after moving image switching is sequentially overwritten from the position of the segment before moving image switching determined by the overwrite segment determination unit among the plurality of segments before moving image switching buffered in the buffer memory. And a reading unit for reading the segment before moving picture switching from the buffer memory and then reading the segment after moving picture switching.

The user terminal according to claim 2 is the user terminal according to claim 1, wherein the download time predicting unit predicts the download time of the segment before moving image switching measured by the download time measuring unit by the download predicting unit. It is characterized by being time.

Further, a user terminal according to claim 3 is the user terminal according to claim 1, wherein the download time prediction unit is a predetermined number of the download time measured by the download time measuring unit immediately before the current time, or The maximum download time is specified from among the plurality of download times measured from the current time to a time before a predetermined time, and the maximum download time is set as the predicted download time. ..

Further, the program according to claim 4 causes a computer to function as the user terminal according to any one of claims 1 to 3.

As described above, according to the present invention, it is possible to shorten the waiting time until the start of viewing another video when the user watching the online video performs zapping.

It is a schematic diagram showing an example of composition of the whole system containing a user terminal by an embodiment of the present invention. 9 is a flowchart illustrating an outline of a processing example by a reception buffer management unit when a user operation is detected. It is a block diagram which shows the structural example of a reception buffer management part. It is a figure which shows the flow of data at the time of normal. It is a figure which shows the flow of data at the time of user operation detection. It is a figure explaining the buffering state of the buffer memory part at the time of user operation detection. It is a figure explaining the example of the determination process of the overwrite segment number by the overwrite segment number determination part. (1) is a diagram for explaining buffer management of adaptive streaming using the FIFO method of the related art. (2) is a diagram for explaining buffer management of adaptive streaming using the new method of the present invention.

Hereinafter, modes for carrying out the present invention will be described in detail with reference to the drawings. The present invention, in a system for performing adaptive streaming in which a video is distributed from a server to a user terminal, buffers a video segment in a FIFO method, and when a user operation is performed to switch the video when passing the video segment to a decoder unit, The present invention is characterized by overwriting a segment after moving image switching from a predetermined portion of a plurality of buffered segments before moving image switching.

As a result, when there is a user operation for switching a moving image, only some of the segments before moving image switching are delivered without passing all the buffered segments before moving image switching to the decoder unit. Then, after the delivery of some of the segments before moving image switching is completed, the segments after moving image switching are delivered. Therefore, the segment after moving image switching is delivered to the decoder unit in a short time after the user operation.

Therefore, when a user who is watching an online video performs zapping, it is possible to shorten the waiting time until the start of viewing another video.

[Overall system]
First, an overall system including a user terminal according to an exemplary embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing a configuration example of an entire system including a user terminal according to an embodiment of the present invention.

This system includes a user terminal 1 and a server 2, and performs adaptive streaming in which a moving image is distributed from the server 2 to the user terminal 1 via the Internet 3. The user terminal 1 and the server 2 are connected via the Internet 3. The internet 3 is, for example, the open internet.

The user terminal 1 includes a communication interface 10, an OS (operating system) 11, a WEB browser 12, a reception buffer management unit 13, a decoder unit 14, and a display unit 15. The user terminal 1 may be a personal computer or a portable terminal device such as a smartphone. In short, the user terminal 1 may be anything as long as it has a function of downloading a video from the server 2, buffering it, and playing it back.

The communication interface 10 transmits/receives data between the user terminal 1 and the server 2 via the Internet 3 according to a predetermined protocol. The communication interface 10 is, for example, Ethernet (Ethernet (registered trademark)).

The OS 11 is software for controlling execution of various programs, and manages the communication interface 10, the WEB browser 12, the reception buffer management unit 13, the decoder unit 14, and the display unit 15 as basic functions. The OS 11 may be, for example, Windows (registered trademark) or iOS.

The WEB browser 12 is software for browsing a WEB page, and may be, for example, Internet Explorer (Internet Explorer, registered trademark) or Chrome (Chrome, registered trademark).

The reception buffer management unit 13 buffers the segment of the moving image distributed from the server 2 by the FIFO method and transfers the segment to the decoder unit 14. When the reception buffer management unit 13 detects the zapping operation by the user, the reception buffer management unit 13 buffers another moving image segment distributed from the server 2 by a new method instead of the FIFO method.

Specifically, the reception buffer management unit 13 overwrites a segment of another moving image accompanying the zapping from a predetermined position on a plurality of buffered segments of the moving image being viewed. The reception buffer management unit 13 sequentially transfers the remaining segments that are not the target of overwriting to the decoder unit 14 and then transfers another moving image segment to the decoder unit 14.

FIG. 8(2) is a diagram illustrating buffer management of adaptive streaming using the new method of the present invention. Similar to FIG. 8A, the segment of the moving image that is being viewed is the segment before moving image switching, and the segment of another moving image that is switched by zapping is the segment after moving image switching.

It is assumed that the reception buffer management unit 13 of the user terminal 1 buffers the moving image pre-switching segments SG1 to SG5. When zapping is performed by the user in this state, a request request for another moving image is transmitted from the user terminal 1 to the server 2.

Then, the reception buffer management unit 13 of the user terminal 1 receives the segments SG3', SG4', etc. after moving image switching from the server 2. Then, the reception buffer management unit 13 overwrites the moving image post-switching segments SG3', SG4', etc. from the position of the third moving image pre-switching segment SG3 of the buffered moving image pre-switching segments SG1 to SG5. Here, the location to be overwritten is determined based on the predicted download time of the segment after moving image switching. Details will be described later.

The reception buffer management unit 13 sequentially reads the buffered moving image pre-switching segments SG1 and SG2 and transfers them to the decoder unit 14. Then, the reception buffer management unit 13 sequentially reads the buffered moving image post-switching segments SG3', SG4' and the like after the transfer of the moving image pre-switching segments SG1 and SG2 is completed, and passes them to the decoder unit 14.

In this way, when zapping is performed by the user, only the moving image pre-switching segments SG1 and SG2 are passed without passing all the buffered moving image pre-switching segments SG1 to SG5. In addition, the segment after the moving image segment SG3 and the like of another moving image are overwritten in the segment after the moving image segment SG3.

That is, when zapping is performed by the user, among the buffered moving image pre-switching segments SG1 to SG5, only the moving image pre-switching segments SG1 and SG2 are transferred, and the moving image pre-switching segments SG3 to SG5 are transferred. I don't know. Then, instead of the segments SG3 to SG5 before the moving image switching, the segments SG3' after the moving image switching are delivered.

Therefore, the switching time of the moving image due to the zapping by the user, that is, the waiting time until the start of the viewing of another moving image to be watched next is shortened by the time during which the segments SG3 to SG5 before moving image switching are not passed.

Returning to FIG. 1, the decoder unit 14 inputs the segment from the reception buffer management unit 13, decodes the moving image data of the segment encoded by various encoding methods such as H264 and H265, and displays it on the display unit 15. .. Thereby, the moving image is reproduced. The display unit 15 may be a television screen or a personal computer monitor screen.

The server 2 receives a segment request from the user terminal 1 via the Internet 3, and transmits a moving image segment corresponding to the segment request to the user terminal 1 via the Internet 3. The server 2 may be any computer device that can distribute a moving image.

[Reception buffer management unit 13]
Next, the reception buffer management unit 13 of the user terminal 1 shown in FIG. 1 will be described in detail. FIG. 2 is a flowchart showing an outline of a processing example by the reception buffer management unit 13 when a user operation is detected.

The reception buffer management unit 13 measures the download time of the segment of the moving image viewed by the user (step S201).

The reception buffer management unit 13 detects a user's zapping operation (step S202). Then, the reception buffer management unit 13 transmits a segment request for requesting the transmission of the segment of the moving image to the server 2 in order to reproduce the moving image designated by the zapping (another moving image) (step S203). ..

Further, the reception buffer management unit 13 predicts the download time of the segment (segment after moving image switching) of the moving image based on the download time measured in step S201 for another moving image (step S204).

The reception buffer management unit 13 determines the buffering overwrite location (overwrite segment number) for another moving image based on the download time (predicted download time) predicted in step S204 (step S205). That is, the reception buffer management unit 13 determines the overwrite segment number indicating the overwrite location in the plurality of segments being viewed (segment before moving image switching) based on the predicted download time for another moving image.

In the example shown in FIG. 8(2), another moving image is overwritten in order on the segment after the moving image switching segment SG3, so the overwrite segment number is 3.

The reception buffer management unit 13 receives the segment corresponding to the segment request transmitted in step S203 from the server 2 (step S206). Then, the reception buffer management unit 13 overwrites the segment with the overwrite segment number determined in step S205 (step S207).

Thereby, the transmission of the segment request and the reception of the segment after switching the moving image are repeated for the moving image designated by the zapping. Then, the segment after the moving image switching is sequentially overwritten from the position of the overwrite segment number, and the buffering of the segment after the moving image switching starts.

The reception buffer management unit 13 passes the buffered segment before moving image switching, which is being viewed, to the decoder unit 14, and then passes the segment after moving image switching to the decoder unit 14 (step S208).

As a result, after the remaining segments before moving image switching, in which the segments after moving image switching have not been overwritten, are reproduced, the segments after moving image switching of the moving image designated with zapping are reproduced.

Next, the configuration and data flow of the reception buffer management unit 13 will be described. FIG. 3 is a block diagram showing a configuration example of the reception buffer management unit 13. FIG. 4 is a diagram showing a data flow during normal operation, and FIG. 5 is a diagram showing a data flow upon detection of a user operation.

The reception buffer management unit 13 includes a download time measurement unit 20, a user operation detection unit 21, a segment request unit 22, a download time prediction unit 23, a communication unit 24, an overwrite segment number determination unit (overwrite segment determination unit) 25, A segment receiver 26, a write controller 27, a decoder transfer controller (reader) 28, and a buffer memory 29 are provided.

Hereinafter, the processing of each component provided in the reception buffer management unit 13 will be described with reference to FIGS. 4 and 5.

(Normal time)
First, with reference to FIG. 4, a process of each component during a normal time when the user is watching a moving image will be described. The segment requesting unit 22 generates a segment request (SG request) requesting transmission of the moving image segment, and outputs the segment request to the communication unit 24.

The communication unit 24 inputs the segment request from the segment request unit 22 and transmits a packet including the segment request to the server 2. Then, the communication unit 24 receives a packet including the segment (SG) corresponding to the segment request from the server 2, and outputs the segment to the segment reception unit 26.

Further, the communication unit 24 acquires the time T1 at which the segment request is transmitted to the server 2 from the clock (not shown) and the time T2 at which the segment corresponding to the segment request is received from the server 2 from the clock (not shown). Then, the communication unit 24 outputs the times T1 and T2 to the download time measuring unit 20. In this case, the communication unit 24 acquires the times T1 and T2 for each of the transmitted segment request and the received segment and outputs them to the download time measurement unit 20.

The download time measuring unit 20 inputs the times T1 and T2 from the communication unit 24, subtracts the time T1 from the time T2 (T2-T1), and measures the subtraction result as the download time. Then, the download time measuring unit 20 stores the measured download time in a memory (not shown). In this case, the download time measuring unit 20 measures the download time of the segment for each set of the segment request transmitted by the communication unit 24 and the received segment (for each segment) and stores it in the memory.

As a result, the download time of the segment of the moving image being viewed by the user is sequentially stored in the memory (not shown). The longer the congestion of the Internet 3, the longer the download time, and the shorter the congestion, the shorter the download time.

The download time measuring unit 20 may measure the download time of a segment for each segment, or may measure the download time at a predetermined interval (every predetermined time or every predetermined number of times).

The segment receiving unit 26 inputs a segment from the communication unit 24 and outputs the segment to the writing control unit 27.

The write control unit 27 inputs a segment from the segment receiving unit 26 and sequentially writes the segment in the buffer memory unit 29 by the FIFO method. As a result, the segments of the moving image being viewed by the user are sequentially written in the buffer memory unit 29.

Depending on the congestion state of the Internet 3, the user terminal 1 does not always receive the segments in ascending order. For this reason, when the user terminal 1 receives the segment with the changed number, the writing control unit 27 rearranges the segment with the changed number in ascending order and then stores the segment in the buffer memory unit 29.

In a state where a predetermined number of segments are written in the buffer memory unit 29, the decoder delivery control unit 28 sequentially reads the segments from the beginning by the FIFO method based on the reproduction time of each segment, and receives the segments to the decoder unit 14. hand over. As a result, each segment transferred from the buffer memory unit 29 to the decoder unit 14 is reproduced at the corresponding reproduction time.

In this way, the download time of each segment is measured by the download time measuring unit 20 during the normal time when the user is watching the moving image.

(When user operation is detected)
Next, with reference to FIG. 5, a process of each component when a user operation is detected will be described. When the user operation detecting unit 21 detects an operation for the user to select another moving image, that is, an operation for zapping by the user, the user operation detecting unit 21 downloads another moving image (a moving image different from the moving image being viewed) switched by zapping. The moving image instruction is output to the segment request unit 22.

When the different video instruction is input from the user operation detection unit 21, the segment request unit 22 generates a segment request that requests transmission of a segment of another video indicated by the different video instruction, and outputs the segment request to the communication unit 24. .. Further, the segment requesting unit 22 outputs another moving image segment request indicating that the segment request is output to the download time prediction unit 23.

The communication unit 24, the download time measuring unit 20, and the segment receiving unit 26 perform the same processing as in FIG. In this case, the download time measuring unit 20 outputs the measured download time (DL time) to the download time predicting unit 23 for the video being viewed before zapping. Further, the segment receiving unit 26 outputs the segment of another moving image after zapping to the writing control unit 27.

The download time prediction unit 23 inputs another video segment request from the segment request unit 22 and also inputs the download time of the video being viewed before zapping from the download time measurement unit 20. Then, the download time prediction unit 23 predicts the download time of another video indicated by the different video segment request based on the download time of the video that is being viewed before zapping, and obtains the predicted download time.

The download time prediction unit 23 outputs the download predicted time (DL predicted time) of another moving image after zapping to the overwrite segment number determination unit 25.

For example, the download time prediction unit 23 identifies the maximum download time of the predetermined number of download times measured most recently by the download time measurement unit 20 and sets it as the predicted download time. Alternatively, the download time predicting unit 23 specifies the maximum download time among the plurality of download times measured by the download time measuring unit 20 from the current time to the time before the predetermined time (within the predetermined time), This is set as the estimated download time.

This makes it possible to set the download time when the congestion of the Internet 3 is the largest among the plurality of latest download times as the predicted download time.

The download time prediction unit 23 may calculate an average value of a plurality of download times measured most recently by the download time measurement unit 20 and set the average value as the download predicted time. Further, the download time prediction unit 23 may add a predetermined value to the calculated average value and set the addition result as the download predicted time.

Further, the download time prediction unit 23 may specify the (latest) download time measured at the time closest to the current time and set this as the download predicted time. The reason for setting the predicted download time using the latest download time is that the download time does not change significantly in a short time from a micro viewpoint.

The overwrite segment number determination unit 25 inputs the download estimated time from the download time estimation unit 23. Then, the overwrite segment number determination unit 25, based on the estimated download time, of the plurality of segments being viewed written in the buffer memory unit 29, the segment to be overwritten, that is, the overwrite portion indicating the overwrite location. Determine the segment number. The overwrite segment number determination unit 25 outputs the overwrite segment number to the write control unit 27.

Here, the overwrite segment number is determined to be a number of a portion farther from the first segment read by the FIFO method as the download prediction time is longer, and a number of a portion closer to the first segment as the download prediction time is shorter. Is decided. That is, the overwrite segment number is a viewing number that allows the first segment in another moving image to be overwritten before the segment being viewed is delivered to the decoder unit 14 among the plurality of buffered viewing segments. It is the number of the segment inside and the number of the segment closest to the beginning.

In addition, when the download time prediction unit 23 sets a predetermined number of times close to the current time or the maximum download time within the predetermined time to the download predicted time, the predicted download time is a time in which the congestion of the Internet 3 is reflected. Therefore, the overwrite segment number is determined to be a number farther from the leading segment read by the FIFO method as the congestion of the Internet 3 is larger, and as the congestion of the Internet 3 is smaller, the overwrite segment number of the portion closer to the leading segment is determined. The number is decided.

FIG. 6 is a diagram illustrating a buffering state of the buffer memory unit 29 when a user operation is detected, and FIG. 7 is a diagram illustrating an example of an overwrite segment number determination process by the overwrite segment number determination unit 25. ..

As shown in FIG. 6, the buffer memory unit 29 stores a maximum of n times the time length per segment (segment length), that is, n segments. The buffering size of the buffer memory unit 29 is segment length×n. n is a positive integer.

Further, the number of the first segment buffered when the user operation is detected is 1, the next number is 2,..., And the number of the last segment is n. The storage locations of the segments are P1, P2,..., Pn, respectively.

In the FIFO method, the first segment SG1 stored in the location P1 is read by the decoder transfer control unit 28 (α1), and the segments SGn,..., SG2 stored in the locations Pn,... , Pn-1,..., P1 respectively (α2). Then, the new segment is written by the writing control unit 27 at the location Pn (α3).

It is assumed that the buffer memory unit 29 at the time of detecting a user operation stores the moving image pre-switching segments SG1, SG2,..., SGn that are being viewed before zapping.

Further, as shown in FIG. 7, the reproduction time (reproduction start time) of each of the segments before moving images SG1, SG2,..., SGn being viewed before zapping shown in FIG. 6 is t1, t2,. .., tn. The playback time indicates the time from the beginning of the moving image stream.

The overwrite segment number determination unit 25 manages the buffering state of the buffer memory unit 29 at the time of user operation detection shown in FIG. 6 and the reproduction times t1, t2,..., Tn shown in FIG. Be present.

The overwrite segment number determination unit 25 adds the download prediction time input from the download time prediction unit 23, the decoding time in the decoder unit 14, the display time in the display unit 15 and the like to obtain the predicted playback time of another moving image after zapping. Ask. Then, the overwrite segment number determination unit 25 adds the predicted reproduction time to the current time when the user operation is detected to obtain the predicted reproduction time. The current time is acquired from a clock (not shown).

The overwrite segment number determination unit 25 determines the latest reproduction time that exceeds the predicted reproduction time, and identifies the segment corresponding to the reproduction time. Then, the overwrite segment number determination unit 25 specifies the location of the buffer memory unit 29 in which the segment is stored, and determines the segment number as the overwrite segment number.

In the example of FIGS. 6 and 7, the overwrite segment number determination unit 25 determines the latest reproduction time t3 that exceeds the predicted reproduction time, and specifies the segment SG3 before moving image switching corresponding to the reproduction time t3. Then, the overwrite segment number determination unit 25 specifies the location P3 of the buffer memory unit 29 in which the moving image pre-switching segment SG3 is stored, and determines the number of the moving image pre-switching segment SG3 as the overwrite segment number 3.

Returning to FIG. 5, the writing control unit 27 inputs the first segment after moving image switching in another moving image after zapping from the segment receiving unit 26, and inputs the overwrite segment number from the overwrite segment number determining unit 25. To do. Then, the writing control unit 27 determines the position of the segment before moving image switching of the overwrite segment number stored in the buffer memory unit 29, and determines the first segment after moving image switching as the segment before moving image switching of the overwrite segment number. Overwrite in place of.

As a result, before the moving image pre-switching segment of the overwrite segment number being viewed is transferred to the decoder unit 14, the first moving image post-switching segment in another moving image is overwritten in that portion.

In the examples of FIGS. 6 and 7, the moving image pre-switching segment SG3 being viewed is stored in the location P3 of the buffer memory unit 29. In this case, the writing control unit 27 determines the location P3 in which the segment SG3 before moving image switching is stored, and overwrites the location P3 in the buffer memory unit 29 with the first segment after moving image switching in another moving image.

Actually, during the download time of the segment after the first video switching, the segment before the video switching being viewed stored in the buffer memory unit 29 is transferred to the decoder unit 14, and the remaining segments before the video switching before the video viewing are switched. Shift in the buffer memory unit 29.

When the moving image pre-switching segments SG1 and SG2 stored in the buffer memory unit 29 that have been viewed are already read by the decoder passing control unit 28 and passed to the decoder unit 14, the moving image pre-switching segment SG3 is located at a location. It has shifted to P1. In this case, the writing control unit 27 determines the location P1 in which the segment SG3 before moving image switching is stored, and overwrites the location P1 in the buffer memory unit 29 with the first segment after moving image switching.

After that, the writing control unit 27 sequentially stores the moving image switched segments input from the segment reception unit 26 from the position after the overwritten portion of the buffer memory unit 29. As a result, buffering of the segment after moving image switching of another moving image due to zapping starts.

The decoder delivery control unit 28 reads the moving image pre-switching segment being viewed from the buffer memory unit 29, and passes the read moving image pre-switching segment to the decoder unit 14. Then, after the delivery of the segment before moving image switching which is being viewed is completed, the decoder delivery control unit 28 reads the segment after moving image switching of another moving image from the buffer memory unit 29, and the read segment after moving image switching to the decoder unit 14. Hand over.

In the example of FIGS. 6 and 7, the buffer memory unit 29 stores the moving image pre-switching segments SG1 and SG2 being viewed and the moving image post-switching segments SG3′,..., SGn′ of another moving image. And In this case, the decoder delivery control unit 28 sequentially reads out the moving image pre-switching segments SG1 and SG2 that are being viewed from the buffer memory unit 29 and delivers them to the decoder unit 14. Then, the decoder delivery control unit 28 reads out the moving image switched segments SG3′,..., SGn′ of another moving image from the buffer memory unit 29, and delivers them to the decoder unit 14.

As a result, after the remaining segment before moving image switching that has not been overwritten by the writing control unit 27 is played back, the segment after moving image switching of another moving image is played back.

As described above, according to the user terminal 1 of the embodiment of the present invention, the download time measurement unit 20 of the reception buffer management unit 13 measures the download time of the segment of the moving image being viewed. When the user operation detection unit 21 detects the user's zapping operation, the download time prediction unit 23 determines the other video after zapping based on the measured download time of the video being viewed (segment before video switching). Predict the download time of a segment (segment after video switching).

The overwriting segment number determination unit 25, for the segment after moving image switching, based on the predicted download time (predicted download time), overwrite portions in the plurality of moving image pre-switching segments buffered in the buffer memory unit 29 (up Call segment number).

The writing control unit 27 sequentially overwrites the segments after moving image switching from the location of the overwrite segment number in the buffer memory unit 29.

The decoder passing control unit 28 passes the segment before moving image switching buffered in the buffer memory unit 29 to the decoder unit 14, and then passes the segment after moving image switching to the decoder unit 14.

As a result, when the zapping is performed, all the buffered segments before moving image switching are not passed to the decoder unit 14, and some segments before moving image switching are passed and after moving images are switched. The segment is handed over. That is, after the remaining segments that have not been overwritten and before moving images have been played back, the segments after moving images have been played.

As described above, when the user performs zapping, the user can watch the segment after moving picture switching without waiting for completion of watching all the segments before moving picture switching buffered in the buffer memory unit 29.

Therefore, when a user who is watching an online video performs zapping, it is possible to shorten the waiting time until the start of viewing another video. In addition, it is possible to quickly and continuously switch from the video being viewed to another video.

In addition, the download time prediction unit 23 sets the maximum download time as the predicted download time out of the predetermined number of times or the predetermined time based on the current time. The overwrite segment number determination unit 25 determines the overwrite segment number of the segment after moving image switching based on the maximum download time which is the predicted download time.

As a result, the download time when the congestion of the Internet 3 is the largest is set as the download estimated time, and the overwrite segment number is a number that reflects the largest congestion. Therefore, the write control unit 27 overwrites the leading segment after moving image switching on the overwrite segment number in the buffer memory unit 29, even if there is congestion on the Internet 3, Before the moving image pre-switching segment stored in the location is transferred to the decoder unit 14, the location can be surely overwritten.

Therefore, when the user who is watching the online video performs the zapping, it is possible to reliably reduce the waiting time until the start of the viewing of another video.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the technical idea thereof.

A general computer can be used as the hardware configuration of the user terminal 1 according to the embodiment of the present invention. The user terminal 1 is configured by a computer including a CPU, a volatile storage medium such as a RAM, a non-volatile storage medium such as a ROM, and an interface.

The functions of the communication interface 10, the OS 11, the WEB browser 12, the reception buffer management unit 13, the decoder unit 14, and the display unit 15 provided in the user terminal 1 are realized by causing the CPU to execute a program describing these functions. To be done. Further, regarding the reception buffer management unit 13, the download time measurement unit 20, the user operation detection unit 21, the segment request unit 22, the download time prediction unit 23, the communication unit 24, the overwrite segment number determination unit 25, the segment reception unit 26, and the writing. Each function of the input control unit 27, the decoder delivery control unit 28, and the buffer memory unit 29 is realized by causing the CPU to execute a program describing these functions.

These programs are stored in the storage medium, read by the CPU, and executed. Further, these programs can be stored and distributed in a storage medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, etc., and can be distributed via a network. You can also send and receive.

1 User Terminal 2 Server 3 Internet 10 Communication Interface 11 OS (Operating System)
12 WEB browser 13 reception buffer management unit 14 decoder unit 15 display unit 20 download time measurement unit 21 user operation detection unit 22 segment request unit 23 download time prediction unit 24 communication unit 25 overwrite segment number determination unit (overwrite segment determination unit)
26 segment receiver 27 write controller 28 decoder delivery controller (reader)
29 Buffer memory section

Claims (4)

In a user terminal that receives a moving image distributed via the Internet for each segment, buffers and reads the segment by the FIFO method, and reproduces the moving image,
A download time measuring unit for measuring the download time of the segment,
When a switching operation for playing another moving image is performed by the user, the moving image of the another moving image is based on the download time of the segment before moving image switching in the moving image before the switching operation measured by the download time measuring unit. A download time prediction unit that predicts the download time of the segment after switching and obtains the download prediction time;
Overwrite segment determination that determines the before-video-switching segment to be overwritten among the plurality of before-video-switching segments buffered in the buffer memory based on the above-mentioned predicted download time obtained by the download-time predicting unit Department,
When the segments after the movie switching are sequentially received, the segments after the movie switching are determined by the overwrite segment determination unit among the plurality of segments before the movie switching buffered in the buffer memory. A writing control unit that sequentially overwrites from the segment before switching,
A read unit that reads the segment before moving picture switching from the buffer memory and then reads the segment after moving picture switching;
A user terminal comprising: In the user terminal according to claim 1,
The download time prediction unit,
The user terminal, wherein the download time of the segment before moving image switching measured by the download time measuring unit is set as the predicted download time. In the user terminal according to claim 1,
The download time prediction unit,
A predetermined number of the download times measured closest to the current time by the download time measuring unit, or a maximum of the plurality of download times measured from the current time to a time before the predetermined time. A user terminal, wherein a time is specified, and the maximum download time is set as the predicted download time. A program for causing a computer to function as the user terminal according to any one of claims 1 to 3.

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