JP2018133664A - Distribution device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for seamless changeover of a video stream of a reproduction object, with a simple configuration.SOLUTION: A distribution device 10 includes acquisition parts 11 provided corresponding to multiple video streams, respectively, and acquiring a play list indicating information for processing segments obtained by dividing the video streams, a generation part 14 for generating a reference play list, referenced by a reproduction device 20, and indicating the information for processing the segments obtained by dividing the video streams of reproduction object, and a distribution part 15 for distributing the reference play list to the reproduction device 20. When the video streams of reproduction object are changed over, the generation part 14 updates the reference play list by a play list being acquired by the acquisition part 11, and provided previously corresponding to the video streams of changeover destination, and the distribution part 15 distributes the reference play list updated by the generation part 14 to the reproduction device 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distribution device and a program for distributing a video stream to a playback device.

  As a video distribution method via a communication network such as the Internet, a video stream according to HTTP (Hypertext Transfer Protocol) represented by HLS (HTTP Live Streaming) and MPEG-DASH (Moving Picture Experts Group-Dynamic Adaptive Streaming over HTTP) There is an HTTP-based moving image distribution method for distributing to a playback device (see Non-Patent Document 1). The HTTP-based moving image distribution method has an advantage that a video stream can be distributed using a standard Web server.

  Taking the above-mentioned HLS as an example, the video stream is divided into video files (segments) having a predetermined time length by the encoder on the delivery side. Also, a playlist indicating information for processing the segment obtained by dividing the video stream in the playback device is generated. The playlist includes information such as segment location, segment time length, segment order, and the like.

  The playback device acquires a playlist of a video stream to be played back from a Web server that distributes the playlist and segments according to HTTP, and sequentially downloads and plays back the segments of the video stream to be played back according to the acquired playlist. To do.

"HTTP Live Streaming draft-pantos-http-live-streaming-20", [online], [Search December 26, 2016], Internet <https://tools.ietf.org/html/draft-pantos- http-live-streaming-20>

  In the HTTP-based moving image distribution method as described above, there is a problem in handling a playlist on the playback side (playback apparatus).

  Taking HLS as an example, playback of a video stream can be started by an operation on a Web browser provided in the playback device. However, there are cases in which a player who plays a video stream cannot perform dynamic processing using JavaScript (registered trademark) or the like. In such a case, when switching the video stream to be played back, it is necessary to temporarily stop the player, re-read the playlist of the video stream to be switched by the Web browser, and then start the player again.

  As described above, the conventional HTTP-based moving image distribution method has a problem that it is difficult to seamlessly switch the video stream to be reproduced with a simple configuration.

  An object of the present invention, which has been made in view of the above problems, is to provide a distribution apparatus and a program that enable seamless switching of a video stream to be reproduced with a simple configuration.

  In order to solve the above problems, a distribution device according to the present invention is a distribution device that distributes to a playback device one of a plurality of video streams divided into a plurality of segments, each corresponding to each of the plurality of video streams. An acquisition unit configured to acquire a playlist indicating information for processing the segment obtained by dividing the video stream, and a segment obtained by dividing the video stream to be reproduced by the reproduction device, which is referred to by the reproduction device. A generation unit that generates a reference playlist indicating information to be processed, and a distribution unit that distributes the reference playlist generated by the generation unit to the playback device, the generation unit including the playback When the video stream to be played back on the device is switched, it corresponds to the video stream of the switching destination acquired by the acquisition unit. The playlist is provided because update the playlist for the reference, the distribution unit distributes the reference play list that is updated by the generating unit to the reproducing apparatus.

  Further, in the distribution device according to the present invention, when the video stream to be played back by the playback device is switched, the switching segment is determined using the segment of the video stream of the switching source and the segment of the video stream of the switching destination. A switching segment generation unit for generating, the distribution unit updates the reference playlist based on the switching segment, and after updating the reference playlist based on the switching segment, It is preferable that the reference playlist is updated by a playlist provided in advance corresponding to the video stream.

  Further, in the distribution device according to the present invention, the switching segment generation unit generates a switching segment by combining the segment of the switching source video stream and the segment of the switching destination video stream, and the distribution It is preferable that the unit updates the reference playlist so that the segment of the switching destination video stream is replaced by the switching segment generated by the switching segment generation unit.

  Further, in the distribution device according to the present invention, the switching segment generation unit includes a still image for one frame of the segment of the switching source video stream and a still image for one frame of the segment of the switching destination video stream. Based on the switching segment, the distribution unit generates the switching segment generated by the switching segment generation unit next to the segment of the switching source video stream and the segment of the switching destination video stream. It is preferable to update the reference playlist so that it is inserted between the segments.

  Further, in the distribution device according to the present invention, the switching segment generation unit includes a still image for one frame of the segment of the switching source video stream and a still image for one frame of the segment of the switching destination video stream. And the distribution unit updates the reference playlist so that the segment of the switching destination video stream is replaced by the switching segment generated by the switching segment generation unit. It is preferable to do.

  Further, in the distribution device according to the present invention, the switching segment generation unit, when switching between the plurality of video streams is performed in a predetermined order, the switching source video stream segment and the switching source The switching segment is generated using each of one or more video stream segments that can be switched from the video stream, and the distribution unit can switch from the switching source video stream to the switching source video stream. When switching to any one of the video streams, based on the segment of the switching source video stream and the segment of the switching destination video stream among the switching segments generated by the switching segment generation unit The reference playlist is updated based on the generated switching segment. It is preferred.

  Moreover, in order to solve the said subject, the program which concerns on this invention makes a computer function as said delivery apparatus.

  The playback apparatus and program according to the present invention enable seamless switching of video streams to be played back with a simple configuration.

It is a figure which shows the structural example of the delivery apparatus which concerns on one Embodiment of this invention. It is a sequence diagram for demonstrating operation | movement of the delivery apparatus shown in FIG. It is a figure which shows an example of the production | generation method of the segment for switching by the segment generation part for switching shown in FIG. It is a figure which shows another example of the generation method of the switching segment by the switching segment production | generation part shown in FIG. It is a flowchart which shows an example of operation | movement of the delivery apparatus shown in FIG. It is a flowchart which shows another example of operation | movement of the delivery apparatus shown in FIG. It is a figure which shows an example of the switching of the video stream of the reproduction | regeneration object between several video streams. It is a figure for demonstrating switching of the video stream of the reproduction | regeneration object centering on the specific video stream shown in FIG. It is a figure for demonstrating the segment for a switch which should be produced | generated with respect to the switching of the video stream of the reproduction | regeneration object between several video streams shown in FIG. It is a figure which shows another example of the switching of the video stream of the reproduction | regeneration object between several video streams. FIG. 11 is a diagram for describing switching of a video stream to be played around a specific video stream shown in FIG. 10. [Fig. 11] Fig. 11 is a diagram for describing a switching segment to be generated in response to switching of a video stream to be reproduced between a plurality of video streams illustrated in Fig. 10.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration example of a distribution device 10 according to an embodiment of the present invention. The distribution apparatus 10 according to the present embodiment is provided in the distribution system 1 on the distribution side of the video stream, and distributes any of the plurality of distribution target video streams to the reproduction apparatus 20 on the reception side.

  The distribution device 10 illustrated in FIG. 1 includes an acquisition unit 11, a switching segment generation unit 12, a reception unit 13, a generation unit 14, and a distribution unit 15.

  The acquisition unit 11 acquires a playlist obtained by dividing a video stream generated by an encoder (not shown) in the distribution system 1 and information for processing the segment, and generates a switching segment generation unit 12 and a generation unit. 14 for output. Normally, there are a plurality of video streams to be distributed by the distribution system 1. Examples of the plurality of video streams include a video stream having different contents, a video stream provided as a production system and a standby system, and a video stream having different bit rates.

  The segment generation unit 12 for switching uses the segment of the video stream acquired by the acquisition unit 11, for example, a segment (switching segment) that is delivered to the playback device 20 when the playback target video stream is switched in the playback device 20. Is generated and output to the generation unit 14. Specifically, for example, when switching the video stream to be reproduced from the video stream A to the video stream B, the switching segment generation unit 12 and the segment of the video stream A that is the switching source video stream and the switching destination video A segment for switching is generated using the segment of the video stream B which is a stream.

  The receiving unit 13 receives various requests from the controller 21 that controls the operation of other devices (not shown) in the distribution system 1 and the playback device 20. The request received by the receiving unit 13 is, for example, a switching request for requesting switching of a video stream to be played back by the playback device 20. The switching request may be received from the controller 21 of the playback device 20 or may be received from another device in the distribution system 1. The request received by the receiving unit 13 includes, for example, a reference playlist acquisition request that the playback device 20 refers to in order to process a segment of a video stream to be played back.

  Based on the video stream acquired by the acquisition unit 11, the generation unit 14 generates a reference playlist that the playback device 20 refers to in order to process a segment of the video stream to be played back, and outputs the reference playlist to the distribution unit 15. Further, the generation unit 14 may output the segment of the video stream to be reproduced to the distribution unit 15 according to the reference playlist. Here, for example, when the video stream is played back independently in the plurality of playback devices 20, the generation unit 14 generates a different reference playlist for each playback device 20. For example, when the same video stream is played back by a plurality of playback devices 20, the generation unit 14 generates the same reference playlist for the playback devices 20.

  The distribution unit 15 distributes the reference playlist generated by the generation unit 14 to the playback device 20. In addition, when the segment of the video stream to be reproduced is output from the generation unit 14 according to the reference playlist, the distribution unit 15 distributes the segment to the reproduction device 20. The player 22 of the playback device 20 processes and plays back the segment of the video stream to be played back in accordance with the reference playlist distributed from the delivery device 10.

  Next, the operation of the distribution apparatus 10 according to the present embodiment will be described with reference to the sequence diagram shown in FIG. In FIG. 2, a case where the video stream to be played back in the playback device 20 is switched from the video stream A to the video stream B will be described as an example.

  First, each of the video streams A and B is divided into segments, and a playlist indicating information for processing the segments of each video stream is generated corresponding to each of the video streams A and B.

  Specifically, when the encoder A corresponding to the video stream A starts processing (Start Processing), the video stream A is divided to generate a segment A and stored in a predetermined storage area (Store) (Step S101). ). In addition, the encoder A generates a playlist A corresponding to the video stream A, and updates (updates) the playlist A every time the segment A is generated (step S102).

  Further, when the encoder B corresponding to the video stream B starts processing (Start Processing), the video stream B is divided to generate a segment B and store it in a predetermined storage area (Store) (Step S103). In addition, the encoder B generates a playlist B corresponding to the video stream B, and updates the playlist B every time the segment B is generated (Step S104).

  Thus, a playlist indicating information for processing a segment of each video stream is generated in advance corresponding to each of the video streams A and B.

  The generation unit 14 generates (Create) a reference playlist (Playlist AtoB) to which the playback device 20 refers to play back the video stream to be played back (Step S105).

  The player 22 requests the distribution apparatus 10 to acquire (Get) a reference playlist (Playlist AtoB) (step S106). In response to the request, the distribution unit 15 distributes the reference playlist (Playlist AtoB) generated by the generation unit 14 to the playback device 20 (step S107).

  After generating the reference playlist, the distribution device 10 starts processing for distributing the video stream A to the playback device 20 (Start Processing). First, the acquisition unit 11 requests the Web server corresponding to the video stream A to acquire the playlist A (Get) (step S108). And the acquisition part 11 acquires the play list A transmitted from the web server corresponding to the video stream A according to the request | requirement (step S109). The generation unit 14 copies the playlist A acquired by the acquisition unit 11 to the reference playlist, and updates the reference playlist (Update (Copy A)) (step S110).

  The player 22 requests the distribution apparatus 10 to obtain a reference playlist (Get) (step S111). In response to the request, the distribution unit 15 distributes the reference playlist generated by the generation unit 14 to the playback device 20 (step S112).

  As described above, the reference playlist is a copy of the content of playlist A. The player 22 requests acquisition (Get) of the segment A of the video stream A from the Web server corresponding to the video stream A according to the reference playlist (step S113). In response to the request, the player 22 acquires and reproduces the segment A transmitted from the Web server corresponding to the video stream A.

  Next, it is assumed that an operation input for switching the video stream to be reproduced from the video stream A to the video stream B is performed. The controller 21 requests the distribution apparatus 10 to switch (Change) the video stream to be reproduced from the video stream A to the video stream B (step S115).

  When the playback device 20 requests the playback apparatus 20 to switch the playback target video stream from the video stream A to the video stream B, the acquisition unit 11 sends the segment A of the video stream A to the Web server corresponding to the video stream A. Acquisition (Get) is requested (step S116). And the acquisition part 11 acquires the segment A transmitted from the web server corresponding to the video stream A according to the request | requirement (step 117). In addition, the acquisition unit 11 requests the Web server corresponding to the video stream B to acquire (Get) the segment B of the video stream B (Step S118). And the acquisition part 11 acquires the segment B transmitted from the web server corresponding to the video stream B according to the request | requirement (step S119).

  The switching segment generation unit 12 includes the segment A (segment A of the video stream A that is the switching source video stream) and the segment B (segment B of the video stream B that is the switching destination video stream) acquired by the acquisition unit 11. Is used to generate a switching segment (Segment AtoB) (Generate) (step S120) and store it in a predetermined storage area.

  When the generation of the switching segment is completed (Done) (step S121), the generation unit 14 updates the reference playlist based on the switching segment (Update (AtoB)) (step S122). Specifically, the generation unit 14 writes information such as the location and time length of the switching segment in the reference playlist. Then, the generation unit 14 notifies the playback device 20 through the distribution unit 15 that the processing for switching the video stream to be played back has been completed (Done) (step S123).

  Details of the generation of the switching segment and the update of the reference playlist based on the switching segment will be described later.

  When notified that the process for switching the video stream to be played back has been completed, the player 22 requests the distribution apparatus 10 to obtain a reference playlist (Get) (step S124). In response to the request from the playback device 20, the distribution unit 15 distributes the reference playlist generated by the generation unit 14 to the playback device 20 (step S125).

  As described above, the reference playlist is updated based on the switching segment. The player 22 requests the distribution device 10 to acquire a switching segment (Get) according to the reference play list (step S126). In response to the request, the player 22 acquires the switching segment transmitted from the distribution device 10 (step S127) and reproduces it.

  After generating the switching segment, the distribution device 10 starts processing for distributing the video stream B to the playback device 20 (Start Processing). The acquisition unit 11 requests the Web server corresponding to the video stream B to acquire the playlist B (Get) (step S128). And the acquisition part 11 acquires the play list B transmitted from the web server corresponding to the video stream B according to the request | requirement (step S129). The generation unit 14 copies the playlist B acquired by the acquisition unit 11 to the reference playlist, and updates the reference playlist (Update (Copy B)) (step S130).

  The player 22 requests the distribution apparatus 10 to obtain a reference playlist (Get) (step S131). In response to the request from the playback device 20, the distribution unit 15 distributes the reference playlist generated by the generation unit 14 to the playback device 20 (step S132).

  As described above, the reference play list is a copy of the content of play list B. The player 22 requests acquisition (Get) of the segment B of the video stream B from the Web server corresponding to the video stream B according to the reference play list (step S133). In response to the request, the player 22 acquires and plays back the segment B transmitted from the Web server corresponding to the video stream B.

  As described above, in the present embodiment, the distribution apparatus 10 generates a reference playlist indicating information for processing a segment of a video stream to be reproduced by the reproduction apparatus 20. When the playback target video stream is switched, the distribution device 10 updates the reference playlist with the playlist corresponding to the switching destination video stream.

  Even when the playback target video stream is switched, the playback device 20 only needs to refer to the reference playlist updated in accordance with the switching of the playback target video stream, and does not need to change the referenced playlist. . Therefore, when switching the video stream to be played back, it is not necessary to terminate the player, re-read the playlist of the video stream to be switched by the Web browser, and then start the player again. Therefore, in the present embodiment, it is possible to seamlessly switch the playback target video stream with a simple configuration.

  In FIG. 2, the segment A of the video stream A and the segment B of the video stream B have been described using an example distributed from a Web server corresponding to each video stream, but the present invention is not limited to this. . For example, the distribution device 10 may acquire the segment A of the video stream A and the segment B of the video stream B and distribute them to the playback device 20. In this case, the playback device 20 requests the distribution device 10 to acquire a segment of the video stream to be played back. In response to this request, the distribution device 10 distributes the segment of the video stream to be reproduced to the reproduction device 20.

  In FIG. 2, the switching segment is generated, the reference playlist is updated by the switching segment, and then the reference playlist is updated by the segment B. However, the present invention is limited to this. is not. The switching segment is not always necessary for seamless switching from the video stream A to the video stream B. That is, when the video stream to be played is switched from the video stream A to the video stream B, the reference playlist to which the playlist A corresponding to the video stream A is copied corresponds to the video stream B according to the switching timing. You may update with the playlist B to be. This also enables seamless switching from the video stream A to the video stream B.

  However, when the switching segment is not used, if the video stream A and the video stream B are not synchronized, the playback image may suddenly change (shock) at the time of switching. For example, when a production video stream and a standby video stream having the same content are prepared, and when switching from a production video stream to a standby video stream, the production video stream and the standby video stream are If they are not synchronized, a shock will occur when switching. Note that it is generally difficult to synchronize a plurality of video streams because control of an encoder process corresponding to each video stream is required.

  Therefore, in this embodiment, a switching segment is generated using the segment of the switching source video stream and the segment of the switching destination video stream. Then, after updating the reference playlist using the switching segment, the reference playlist is updated with the playlist corresponding to the switching destination video stream. In this way, it is possible to absorb the synchronization error between the switching source video stream and the switching destination video stream and switch the playback target video stream without causing the user to feel a sudden change in the playback image. Can do.

  Further, by using the switching segment, it is possible to perform switching with the addition of video effects such as animation and fading when switching the video stream to be played back.

  Next, a method for generating the switching segment will be described with reference to FIGS. In the following description, it is assumed that the video stream to be reproduced is switched from the video stream A to the video stream B. In addition, the video stream A is divided into segments A1, A2, A3, A4, A5, A6,. In addition, the video stream B is divided into segments B1, B2, B3, B4, B5, B6,. Then, it is assumed that the video stream to be reproduced is switched from the video stream A to the video stream B after the distribution of the segment A3 of the video stream A.

  FIG. 3 is a diagram illustrating an example of a method for generating a switching segment.

  As described above, the video stream to be played is switched from the video stream A to the video stream B after the segment A3 of the video stream A is distributed. Therefore, the segments A1, A2 and A3 of the video stream A are distributed in this order as a distribution stream to the playback device 20.

  At the time of switching, the switching segment generator 12 selects the segment of the switching source video stream (segment A4 of the video stream A) and the segment of the switching destination video stream (segment B4 of the video stream B) immediately after the switching timing. The moving image is synthesized to generate the switching segment AB4.

  For example, the segment of the switching source video stream, the segment of the switching destination video stream, and the switching segment AB4 that is combined with the moving image are gradually thinned with the passage of time. The moving image is such that the image of the segment of the video stream gradually becomes darker. Also, the switching segment AB4 is a moving image in which, for example, the segment image of the switching source video stream gradually decreases and the switching destination video stream segment image gradually increases with time. . The switching segment AB4 may be a moving image to which animation or the like is added during switching from the segment image of the switching source video stream to the segment image of the switching destination video stream.

  The switching segment AB4 is not limited to the above-described example, and can be generated by various video synthesis methods as long as the switching source video stream segment image and the switching destination video stream segment image are smoothly switched. can do.

  The generated switching segment AB4 is replaced with the segment B4 of the switching destination video stream (video stream B). That is, in the example shown in FIG. 3, the segment B4 of the switching destination video stream used to generate the switching segment AB4 is replaced with the switching segment AB4. For this reason, when viewed on the time axis, no new segment is added (the time axis of the segment is maintained).

  Thereafter, the segments B5 and B6 following the segment B4 of the switching destination video stream are sequentially delivered to the playback device 20.

  Therefore, in the reference playlist, after the segment A3 of the switching source video stream A, the switching segment AB4 is distributed, and thereafter, the segment B5 following the segment B4 of the switching destination video stream B is sequentially distributed. Updated.

  FIG. 4 is a diagram illustrating another example of the method for generating the switching segment.

  As described above, the video stream to be played is switched from the video stream A to the video stream B after the segment A3 of the video stream A is distributed. Therefore, the segments A1, A2 and A3 of the video stream A are distributed in this order as a distribution stream to the playback device 20.

  At the time of switching, the switching segment generation unit 12 includes the segment of the switching source video stream (segment A3 of the video stream A) and the segment of the switching destination video stream (segment B3 of the video stream B) immediately before the switching timing. A switching segment AB3 ′ is generated using a still image for one frame (for example, the last frame).

  The switching segment obtained by combining the segment (still image) of the switching source video stream and the segment (still image) of the switching destination video stream can be generated using, for example, a still image switching animation.

  The generated switching segment AB3 ′ is distributed immediately after the segment of the switching source video stream immediately before the switching timing (segment A3 of the video stream A), and thereafter the segments B4, B5 of the switching destination video stream B B6 is delivered sequentially. Therefore, in the example shown in FIG. 4, the segment A3 of the video stream A (the segment of the video stream that is the switching source immediately before the switching timing) and the segment B4 of the video stream B (the segment of the video stream that is the switching destination immediately after the switching timing) ), A switching segment AB3 ′ is inserted. That is, in the example shown in FIG. 4, since the switching segment is inserted between the segment A3 of the switching source video stream A and the segment B4 of the switching destination video stream B, when viewed on the time axis , A new segment has been added (segment time axis is not preserved).

  In the reference playlist, after the segment A3 of the switching source video stream A, the switching segment AB3 ′ is distributed, and then the next segments B4, B5, B6 of the segment B3 of the switching destination video stream B are sequentially distributed. As updated.

  FIG. 5 is a flowchart showing an example of the operation of the distribution apparatus 10 according to the present embodiment.

  The generation unit 14 acquires a playlist of a video stream to be processed (currently to be reproduced) via the acquisition unit 11 (step S201).

  Next, the generation unit 14 determines whether a switching request has been received via the reception unit 13 (step S202).

  If it is determined that the switching request has not been received (step S202: No), the generation unit 14 determines to use (distribute) the segment of the processing target video stream as it is (step S203). The reference playlist is updated with the playlist of the video stream (step S204).

  When it determines with having received the switching request (step S202: Yes), the production | generation part 14 specifies the video stream of a switching destination based on a switching request (step S205).

  Next, the acquiring unit 11 acquires a switching source video stream (current playback target video stream) and a switching destination video stream segment (step S206).

  The switching segment generator 12 determines whether or not to maintain the time axis (step S207). Whether or not to keep the time axis is set as a processing rule in advance.

  If it is determined that the time axis is to be retained (step S207: Yes), the switching segment generator 12 synthesizes the segments of the switching source and switching destination video streams immediately after the switching timing as shown in FIG. Thus, a switching segment is generated (step S208).

  The generation unit 14 updates the reference playlist so that the segment of the switching destination video stream immediately after the switching timing is replaced with the switching segment generated by the switching segment generation unit 12 (step S209). Thereafter, the generation unit 14 updates the reference playlist with the playlist of the switching destination video stream, and returns to the process of step S202.

  When it is determined that the time axis is not retained (step S207: No), the switching segment generation unit 12 corresponds to one frame (for example, the last frame) of the segment of the switching source and switching destination video stream immediately before the switching timing. Are combined to generate a switching segment (step S210).

  The generation unit 14 is replaced with the switching segment generated by the switching segment generation unit 12 between the segment of the switching source video stream immediately before the switching timing and the segment of the switching destination video stream immediately after the switching timing. As such, the reference playlist is updated (step S211). Thereafter, the generation unit 14 updates the reference playlist with the playlist of the switching destination video stream, and returns to the process of step S202.

  In FIG. 5, an example of generating a switching segment in response to a switching request has been described. However, the present invention is not limited to this, and a switching segment may be generated in advance before receiving a switching request. Good. FIG. 6 is a flowchart illustrating an example of the operation of the distribution apparatus 10 when a switching segment is generated in advance before receiving a switching request.

  The generation unit 14 acquires a playlist of a video stream to be processed (currently to be reproduced) via the acquisition unit 11 (step S301).

  Next, the generation unit 14 identifies a switching candidate video stream from the current playback target video stream (step S302).

  Then, the generation unit 14 acquires a segment of the video stream to be processed and the switching candidate via the acquisition unit 11 (Step S303).

  The switching segment generator 12 determines whether or not to maintain the time axis (step S304).

  If it is determined that the time axis is to be retained (step S304: Yes), the switching segment generation unit 12 includes a segment of a video stream to be processed and a segment of a video stream that is a switching candidate, as illustrated in FIG. Are combined to generate a switching segment (step S305).

  The generation unit 14 determines whether a switching request has been received via the reception unit 13 (step S306).

  If it is determined that the switching request has been received (step S306: Yes), the generation unit 14 determines that the segment of the switching destination video stream immediately after the switching timing is the switching segment generated for each switching candidate video stream. Then, the reference playlist is updated so as to be replaced with the switching segment generated using the segment of the switching destination video stream (step S307).

  If it is determined that the switching request has not been received (step S306: No), the generation unit 14 determines to use (distribute) the segment of the processing target video stream as it is (step S308), and the processing target. The reference playlist is updated with the playlist of the video stream (step S309).

  When it is determined that the time axis is not retained (step S304: No), the switching segment generation unit 12 corresponds to one frame (for example, the last frame) of the segment of the processing target video stream and the switching candidate video stream. A still image is synthesized to generate a switching segment (step S310).

  The generation unit 14 determines whether a switching request has been received via the reception unit 13 (step S311).

  When it determines with not having received the switching request | requirement (step S311: No), the production | generation part 14 progresses to the process of step S308.

  If it is determined that the switching request has been received (step S311: No), the generation unit 14 is between the segment of the switching source video stream immediately before the switching timing and the segment of the switching destination video stream immediately after the switching timing. The switching segment generated using the segment of the switching destination video stream among the switching segments generated for each switching candidate video stream is inserted to update the reference playlist (step S312).

  As described with reference to FIG. 6, when the switching segment is generated in advance before the switching request is received, when the number of video streams that can be distributed increases, the number of switching segments to be generated also increases. Segment generation costs increase. Here, when the order of switching between a plurality of video streams is determined in advance, an increase in the generation cost of the switching segment can be suppressed.

  For example, as shown in FIG. 7, it is assumed that there are seven video streams (video streams A to G). And the order of the counterclockwise direction (direction of arrow (1) shown in FIG. 7) such as A → B → C and the clockwise direction (shown in FIG. It is assumed that switching is possible in the order of the direction of the arrow 2).

  In this case, as shown in FIG. 8, when the video stream B is used as a reference, two switching segments A → B and B → C may be generated in the direction of the arrow (1). In the direction of the arrow, two switching segments C → B and B → A may be generated.

  Therefore, as shown in FIG. 9, if a switching segment is generated only between adjacent video streams (switchable video streams) in the directions of the arrows (1) and (2) shown in FIG. Good. Therefore, if the number of video streams is N, the number of switching segments to be generated is (N−1) × 2.

  In addition, for mutual switching between adjacent video streams (for example, A → B, B → A), instead of performing the processing for generating two switching segments in parallel, common processing is performed together. The processing time and calculation cost required for generation can be reduced. If there is no need to consider the sound, the still image of the segment of the switching source video stream and the still image of the segment of the switching destination video stream are combined and replaced with the segment of the switching destination video stream. Thus, the time axis can be maintained. If it is not necessary to maintain the time axis, a switching segment is generated by combining the last frame of the switching source video stream and the last frame of the switching destination video stream, and is inserted before the switching destination video stream. You can also.

  Also, for example, as shown in FIG. 10, it is assumed that there are nine video streams (video streams A to I). In the tiled arrangement as shown in FIG. 10, it is possible to switch between video streams adjacent vertically and horizontally.

  In this case, as shown in FIG. 11, when the video stream E is used as a reference, D → E, E → H, D → E in the direction of the arrow (1) (downward and rightward) shown in FIG. , E → F, and four switching segments may be generated. In the direction of the arrow (2) shown in FIG. 11 (upward and leftward), E → B, H → E, E → D, F → It is only necessary to generate four switching segments E.

  Therefore, as shown in FIG. 12, in the arrangement shown in FIG. 10, it is only necessary to generate switching segments between adjacent video streams, and the number of switching segments to be generated is limited.

  Also, in the tiled arrangement as shown in FIG. 10, two switching segments are generated in parallel for mutual switching (for example, D → E, E → D) between adjacent video streams. Instead, the common processing is performed collectively, so that the processing time and calculation cost required for generation can be reduced. When there is no need to consider the sound, the switching segment can be generated by synthesizing the still image of the segment of the switching source video stream and the still image of the segment of the switching destination video stream. Further, the switching segment generated by combining the still image of the segment of the switching source video stream and the still image of the segment of the switching destination video stream may be replaced with the segment of the switching destination video stream. Alternatively, it may be inserted before the segment of the switching destination video stream.

  As described above, in the present embodiment, the distribution apparatus 10 is provided corresponding to each of a plurality of video streams, and acquires an acquisition unit 11 that acquires a playlist indicating information for processing a segment obtained by dividing the video stream; A generation unit 14 that generates a reference play list indicating information for processing a segment obtained by dividing a video stream to be reproduced by the reproduction device 20 that is referred to by the reproduction device 20, and a reference play generated by the generation unit 14 And a distribution unit 15 that distributes the list to the playback device. When the video stream to be played back by the playback device 20 is switched, the generation unit 14 creates a reference playlist by using a playlist that is acquired in advance by the acquisition unit 11 and corresponding to the switching destination video stream. Update. The distribution unit 15 distributes the reference playlist updated by the generation unit 14 to the playback device 20.

  Even when the playback target video stream is switched, the playback device 20 only needs to refer to the reference playlist updated in accordance with the switching of the playback target video stream, and needs to change the playlist to be referenced. There is no. Therefore, when switching the video stream to be played back, it is not necessary to terminate the player, re-read the playlist of the video stream to be switched by the Web browser, and then start the player again. Therefore, it is possible to seamlessly switch the playback target video stream with a simple configuration.

  A computer can be suitably used to function as the distribution apparatus 10 described above, and such a computer stores a program describing processing contents for realizing each function of the distribution apparatus 10 in a storage unit of the computer. It can be realized by reading and executing this program by a CPU (Central Processing Unit), a GPU (Graphics Processing Unit) or the like of the computer. This program can be recorded on a computer-readable recording medium.

  Or the program for performing each process which the delivery apparatus 10 performs is comprised by the memory which memorize | stores and the processor which performs the program memorize | stored in the memory, and the chip mounted in the delivery apparatus 10 may be provided.

  Although the above embodiments have been described as representative examples, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, it is possible to combine a plurality of constituent blocks described in the configuration diagram of the embodiment into one, or to divide one constituent block.

DESCRIPTION OF SYMBOLS 1 Distribution system 10 Distribution apparatus 11 Acquisition part 12 Switching segment generation part 13 Receiving part 14 Generation part 15 Distribution part 20 Playback apparatus 21 Controller 22 Player

Claims (7)

A distribution device that distributes one of a plurality of video streams divided into a plurality of segments to a playback device,
An acquisition unit that is provided corresponding to each of the plurality of video streams and acquires a playlist indicating information for processing a segment obtained by dividing the video stream;
A generating unit that generates a reference playlist indicating information for processing a segment obtained by dividing a video stream to be reproduced by the reproduction device, which is referred to by the reproduction device;
A distribution unit that distributes the reference playlist generated by the generation unit to the playback device;
When the video stream to be played back on the playback device is switched, the generation unit generates the reference playlist based on the playlist acquired in advance corresponding to the video stream to be switched acquired by the acquisition unit. Updated,
The distribution unit distributes the reference playlist updated by the generation unit to the playback device. The distribution apparatus according to claim 1,
When the video stream to be played back by the playback device is switched, the video recording apparatus further includes a switching segment generation unit that generates a switching segment using the segment of the switching source video stream and the segment of the switching destination video stream ,
The distribution unit updates the reference playlist based on the switching segment, and after updating the reference playlist based on the switching segment, plays that are provided in advance corresponding to the switching destination video stream. A distribution apparatus for updating the reference playlist by a list The distribution device according to claim 2,
The switching segment generation unit generates a switching segment by combining the segment of the switching source video stream and the segment of the switching destination video stream,
The distribution apparatus, wherein the distribution unit updates the reference playlist so that the segment of the switching destination video stream is replaced by the switching segment generated by the switching segment generation unit. The distribution device according to claim 2,
The switching segment generation unit generates a switching segment based on a still image of one frame of the segment of the switching source video stream and a still image of one frame of the segment of the switching destination video stream,
The distribution unit causes the switching segment generated by the switching segment generation unit to be inserted between a segment of the switching source video stream and a segment next to the segment of the switching destination video stream. And the reference playlist is updated. The distribution device according to claim 2,
The switching segment generation unit generates a switching segment based on a still image of one frame of the segment of the switching source video stream and a still image of one frame of the segment of the switching destination video stream,
The distribution apparatus, wherein the distribution unit updates the reference playlist so that the segment of the switching destination video stream is replaced by the switching segment generated by the switching segment generation unit. The distribution device according to any one of claims 2 to 5,
The switching segment generation unit, when switching between the plurality of video streams is performed in a predetermined order, the switching source video stream segment and at least one video switchable from the switching source video stream The switching segment is generated using each of the stream segments,
When the distribution unit is switched from the switching source video stream to any one of the switchable video streams, the switching unit generated by the switching segment generation unit The distribution apparatus, wherein the reference playlist is updated based on a switching segment generated based on the segment of the switching source video stream and the segment of the switching destination video stream among the segments.   The program for functioning a computer as a delivery apparatus as described in any one of Claim 1 to 6.

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