JP2007201557A - Near on-demand broadcast system, near on-demand broadcast method, server apparatus and program therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a near on-demand broadcast system in which a transmission amount is suppressed. <P>SOLUTION: A main server 6 starts transmission of near on-demand streams so that the streams are transmitted in a reproduction order, in the order of stream blocks (a), (b), (c) for each of a plurality of main transmission start times. A first interpolation server 7 starts transmission of first interpolation streams so that stream blocks (a), (b) are transmitted in this reproduction order for each of a plurality of sub transmission start times different from the main transmission start times on the basis of a transmission request signal transmitted from a terminal 3. Upon the receipt of the near on-demand streams when a reception means of the terminal 3 receives the first interpolation streams, a storage section 12 stores the stream block (c). A display section 13 reproduces the stream blocks (a), (b), (c) in this reproduction order. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a near-on-demand broadcasting system, a near-on-demand broadcasting method, a server device, and a program thereof that provide information such as moving images or music in response to requests from a plurality of users.
In the present invention, “server” is synonymous with “server computer”.

  Digital terrestrial television broadcasting has begun, and we are entering an era where high-quality and high-quality television broadcasting can be enjoyed at hand. From April this year, one-segment broadcasting that uses one segment of terrestrial digital broadcasting will start broadcasting for mobiles such as mobile phones, and it will be possible to watch TV outdoors.

  In addition, broadband broadcasting over the Internet communication network (hereinafter referred to as “Internet”) has already started, and broadcasting other than broadcasting using radio waves has been performed, and the form of broadcasting is increasingly diversified.

  However, conventional broadcasting has a major limitation that the program cannot be viewed unless the broadcast time of the program is reached. A server broadcast that systematizes a method of personally recording a program on a VTR and reproducing it at a desired time has also been proposed. However, the program that does not record the server broadcast method is not seen, and it cannot be said that the broadcast sufficiently satisfies the request to watch when the user wants to watch the program. On-demand broadcasting using the Internet has been proposed as a method for meeting the demand (see, for example, Patent Documents 1 and 2).

JP-A-9-51523 JP-A-7-193788

  When viewer access concentrates on an Internet broadcast station server that is an on-demand broadcast base station, this method connects the Internet broadcast station and the viewer's terminal device in a one-to-one relationship. If it is simultaneously accessed from these terminal devices, connection becomes difficult.

  As a means for solving such a problem, there is a method called near-on-demand broadcasting. Although this method is already known and does not require detailed explanation, it is a method of transmitting a program having the same contents at a time interval and transmitting a plurality of times at different time intervals. Although this method reduces the burden on the server, since the program starts intermittently for the viewer, it cannot be viewed unless it waits until the start time, and is a pseudo on-demand broadcast.

  If the transmission interval of this near-on-demand broadcast is reduced as much as possible until the viewer is satisfied, and the number of transmissions is increased, the amount of transmission increases rapidly, increasing the burden on the server and the Internet. In addition, an increase in the amount of transmission cannot be realized as a business, such as an increase in communication expenses.

  Therefore, there is a method that does not increase the load on the server or the network without increasing the transmission amount, the method of reducing the interval of the start time of the near-on-demand broadcast program as much as possible, and not causing the viewer to wait. An apparatus for realizing this is expected.

  An object of the present invention is to provide a near-on-demand broadcasting system, a near-on-demand broadcasting method, a server device, and a program thereof in which the transmission amount is suppressed.

The present invention is a near-on-demand broadcast system including (a) a server device and a terminal device that is communicably connected to the server device via an Internet network,
(B) The server device
(B1) Transmission means for transmitting a stream that can be played back by the terminal device. (B11) A main stream that is one of the streams and that includes a plurality of information blocks having a playback order is stored in advance. A main server that starts transmission of the stream so that each information block is transmitted in the order of reproduction for each of a plurality of main transmission start times with a predetermined main transmission time interval;
(B12) An interpolation stream, which is one of the streams, is a partial information block included in the main stream, and stores an interpolation stream including one or a plurality of information blocks with higher playback order, and the main transmission start time And an interpolation server capable of starting transmission of the interpolated stream so that each information block is transmitted in the order of reproduction at each of a plurality of sub-transmission start times separated by a predetermined sub-transmission time interval. A transmission means;
(B2) transmission control means for causing the interpolation server to start transmission of the interpolation stream based on a transmission request signal transmitted from the terminal device,
(C) The terminal device
(C1) request transmission means for transmitting a transmission request signal to the server device based on the input;
(C2) receiving means capable of receiving a stream transmitted from the server device;
(C3) When one stream is received and another stream including an information block not included in the stream is received, the information block is not included in the one stream and the other stream Storage means for storing the included information blocks;
(C4) A near-on-demand broadcast system including reproduction means capable of reproducing information blocks included in a received stream in the order of reproduction.

  According to the present invention, the main server starts transmission of the main stream so as to be transmitted in the order of reproduction of each information block at each of a plurality of main transmission start times. Further, based on the transmission request signal transmitted from the terminal device, the interpolation server transmits the interpolation stream so that each information block is transmitted in the reproduction order at each of a plurality of sub-transmission start times different from the main transmission start time. To start. The interpolation stream is a part of information blocks included in the main stream, and includes one or a plurality of information blocks having a higher playback order. Therefore, the time during which the interpolation stream is transmitted is shorter than the time during which the main stream is transmitted. Furthermore, transmission from the interpolation server can be controlled by the transmission control unit.

  In the present invention, when receiving a stream by the receiving means, if another stream including an information block not included in one stream is received, the information block is not included in one stream, and Information blocks included in other streams are stored. The reproduction means reproduces the information block of the stream received in the order of reproduction.

The present invention relates to a near-on-demand broadcast system including a server device and a terminal device communicably connected to the server device via an Internet network.
A main stream that is a main stream that is one of the streams that can be played back by the terminal device at a plurality of main transmission start times with a predetermined main transmission time interval, and that includes a plurality of information blocks having a playback order. A main transmission step for starting transmission of each information block from the server device in the order of reproduction;
When a transmission request signal is transmitted from the terminal device to the server device, the interpolation is one of the streams at a plurality of sub-transmission start times that are different from the main transmission start time and have predetermined sub-transmission time intervals. Interpolation stream that is a stream and is a part of information blocks included in the main stream and includes one or a plurality of information blocks with higher playback order, starts transmission of each information block from the server device in the playback order. Sub-transmission process to
A receiving step in which the terminal device receives a stream transmitted from the server device;
When one stream is received and another stream including an information block not included in the stream is received, information that is an information block not included in the one stream and included in the other stream A storage step in which the terminal device stores the block;
A near-on-demand broadcasting method, comprising: a reproduction step in which a terminal device reproduces information blocks included in a received stream in the order of reproduction.

  According to the present invention, in the main transmission step, transmission of the main stream is started from the server apparatus so that the information blocks are transmitted in the order of reproduction of each information block at a plurality of main transmission start times. Further, in the sub-transmission step, the interpolation stream is transmitted so that each information block is transmitted in the reproduction order at a plurality of sub-transmission start times different from the main transmission start time based on a transmission request signal transmitted from the terminal device. Start sending. The interpolation stream is a part of information blocks included in the main stream, and includes one or a plurality of information blocks having a higher playback order. Therefore, the time during which the interpolation stream is transmitted is shorter than the time during which the main stream is transmitted.

  Further, in the present invention, when a stream is received in the reception process, if another stream including an information block not included in one stream is received in the storage process, an information block not included in one stream is received. In addition, information blocks included in other streams are stored. In the reproduction process, the information blocks of the received stream are reproduced in the order of reproduction.

The present invention is communicably connected to a terminal device via an Internet network,
Transmitting means for transmitting a stream that can be played back by a terminal device, a main stream that is one of the streams and includes a plurality of information blocks having a playback order, and a predetermined main transmission time interval A main server that starts transmission of the stream so that each information block is transmitted in the order of reproduction for each of a plurality of main transmission start times with a gap,
An interpolation stream that is one of the streams, is a partial information block included in the main stream, stores an interpolation stream including one or a plurality of information blocks with higher playback order, and differs from the main transmission start time, And an interpolating server capable of starting transmission of the interpolated stream so that each information block is transmitted in the order of reproduction at each of a plurality of sub-transmission start times at predetermined sub-transmission time intervals; ,
The server apparatus includes transmission control means for causing the interpolation server to start transmission of the interpolation stream based on a transmission request signal transmitted from the terminal apparatus.

  According to the present invention, the main server starts transmission of the main stream so as to be transmitted in the order of reproduction of each information block at each of a plurality of main transmission start times. Further, based on the transmission request signal transmitted from the terminal device, the interpolation server transmits the interpolation stream so that each information block is transmitted in the reproduction order at each of a plurality of sub-transmission start times different from the main transmission start time. To start. The interpolation stream is a part of information blocks included in the main stream, and includes one or a plurality of information blocks having a higher playback order. Therefore, the time during which the interpolation stream is transmitted is shorter than the time during which the main stream is transmitted. Further, transmission from the interpolation server can be controlled by the transmission control unit.

  The present invention is a program that causes a computer connected to a terminal device via an Internet network to perform the functions of the server device.

  According to the present invention, the function of the server device can be executed by a computer that is communicably connected to the terminal device via the Internet network.

  According to the present invention, since the interpolation server is included, the interval at which the highest-order information block is transmitted in the reproduction order with the number of main transmission start times of the main stream maintained is set to the main stream only. It can be made shorter than in the case of the conventional technology for transmission. This reduces the waiting time until the highest information block is received. Since the interpolation stream is a part of the main stream, the time during which the interpolation stream is transmitted is shorter than the time during which the main stream is transmitted. Since the time during which the interpolation stream is transmitted is short, the number of sub-transmission start times that elapse between the start of transmission of one interpolation stream and the completion of transmission is suppressed. As a result, the number of interpolation streams transmitted through the Internet network is suppressed, and the transmission amount transmitted from the server device to the Internet network can be suppressed. Since the amount of transmission can be suppressed, even if the sub-transmission time interval is shortened, the burden on the Internet network can be suppressed. Therefore, the sub-transmission time interval can be shortened. Further, since transmission from the interpolation server is not always performed, the minimum transmission amount transmitted from the server device is also smaller than that of the conventional technique.

  Further, in the present invention, the information block that is not included in one stream and is included in the other stream is stored by the storage unit, so the stream is played back in the playback order by the playback unit. be able to. Accordingly, the user can use the terminal device to reproduce a stream in which the transmission time interval of the highest information block is short and the transmission amount is suppressed in the reproduction order.

  Further, according to the present invention, since the sub-transmission step is included, the interval at which the highest-order information block is transmitted in the reproduction order is maintained only in the main transmission step while the number of transmissions of the main stream is maintained. It can be made shorter than in the case of the prior art. This reduces the time to wait until the highest information block is received. Since the interpolation stream is a part of the main stream, the time during which the interpolation stream is transmitted is shorter than the time during which the main stream is transmitted. Since the time during which the interpolation stream is transmitted is short, the number of sub-transmission start times that elapse between the start of transmission of one interpolation stream and the completion of transmission is suppressed. As a result, the number of interpolation streams transmitted through the Internet network is suppressed, and the transmission amount transmitted from the server device to the Internet network can be suppressed. Since the amount of transmission can be suppressed, even if the sub-transmission time interval is shortened, the burden on the Internet network can be suppressed. Therefore, the sub-transmission time interval can be shortened. Also, when the transmission request signal is transmitted, transmission is started in the sub-transmission step, so transmission from the interpolation server is not always performed, and the minimum transmission amount transmitted from the server device is also smaller than that of the conventional technology. Less.

  In the present invention, since information blocks that are not included in one stream in the storage step and are included in other streams are stored, the streams are played back in the playback order in the playback step. Can do. Accordingly, the user can use the terminal device to reproduce a stream in which the transmission time interval of the highest information block is short and the transmission amount is suppressed in the reproduction order.

  According to the present invention, since the interpolation server is included, the interval in which the highest-order information block is transmitted in the reproduction order is transmitted only in the main stream while the number of transmissions of the main stream is maintained. It can be shorter than in the case of technology. This reduces the waiting time until the highest information block is received. Since the interpolation stream is a part of the main stream, the time during which the interpolation stream is transmitted is shorter than the time during which the main stream is transmitted. Since the time during which the interpolation stream is transmitted is short, the number of sub-transmission start times that elapse between the start of transmission of one interpolation stream and the completion of transmission is suppressed. As a result, the number of interpolation streams transmitted through the Internet network is suppressed, and the transmission amount transmitted from the server device to the Internet network can be suppressed. Since the amount of transmission can be suppressed, even if the sub-transmission time interval is shortened, the burden on the Internet network can be suppressed. Therefore, the sub-transmission time interval can be shortened.

  According to the present invention, it is possible to cause a computer that is communicably connected to a terminal device via an Internet line network to execute the function of the server device, and the transmission time interval is shorter than that of the conventional technology, and the transmission amount is suppressed. Can be realized.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. Portions corresponding to the matters described in the preceding forms in each embodiment are denoted by the same reference numerals, and overlapping description may be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

  FIG. 1 is a system diagram showing a near-on-demand broadcasting system 1. The near-on-demand broadcasting system 1 is a system that distributes information such as moving images and music in response to requests from a plurality of viewers and provides the received moving images and music to viewers. The near-on-demand broadcasting system 1 is a system that enables a user to view favorite videos and music at the time that the viewer faces. The near-on-demand broadcasting system 1 intermittently shifts a near-on-demand stream (hereinafter sometimes referred to as “near-on-demand stream”) as a near-on-demand stream, for example, an IP multicast method. Transmit with. The near-on-demand broadcasting system 1 also uses an interpolative stream (hereinafter sometimes referred to as an “interpolated stream”) for artificially shortening the transmission time interval of the near-on-demand stream, for example, IP unicast. Transmit by the method. However, the interpolation stream is not limited to transmission using the IP unicast method, and may be transmission using the multicast method.

  The near on-demand stream that is the main stream is a stream for one program of, for example, a moving image and music to be broadcast. In the present embodiment, the near on-demand stream corresponds to one program of a moving image to be broadcast. The near-on-demand stream is composed of a plurality of stream blocks, and the interpolation stream includes at least one stream block of the plurality of stream blocks, and includes a stream block to be transmitted and reproduced first. Yes. A street block corresponds to an information block.

  FIG. 2 is a system diagram of the server device 2. The near-on-demand broadcast system 1 includes a server device 2 and a terminal device 3, and the server device 2 and the terminal device 3 are communicably connected via the Internet 4. In the present embodiment, a plurality of terminal devices 3 are connected to the Internet 4 via a router 5, and the router 5 distributes information transmitted from the server device 2 to each terminal device 3. Server device 2 is provided, for example, in a broadcasting station. However, the server device 2 is not limited to being provided in a broadcasting station. The server apparatus 2 includes a main server 6 for transmitting a near-on-demand stream, a plurality of interpolation servers for transmitting a plurality of interpolation streams, two interpolation servers 7 and 8 in the present embodiment, and a still image A still image server 9 for transmitting files is included. The main server 6 and the two interpolation servers 7 and 8 correspond to the transmission means 17.

  The main server 6 is a relatively large server that stores data files (hereinafter, simply referred to as “A file”) of the entire broadcast program. In the present embodiment, the A file corresponds to a near on-demand stream and is one of the playback streams, and the playback time of the A file is 60 minutes. However, the playback time of the A file is not limited to 60 minutes, and may be 30 minutes or 120 minutes, and the time is not limited. The main server 6 always transmits from the main server 6 as a near-on-demand broadcast even if there is no request from the viewer. Even with this near-on-demand stream alone, viewing on a simple terminal device 3 that does not use an interpolation stream is possible.

  The two interpolation servers 7 and 8 include a first interpolation server 7 that stores a part of the data file at the head of the A file as an interpolation file (hereinafter may be simply referred to as “B file”), and There is a second interpolation server 8 that stores a partial data file at the beginning of the B file as an interpolation file (C file). However, the number of interpolation servers 7 and 8 is not limited, and three or more interpolation servers may be provided. If necessary, the number of interpolation servers to be further interpolated may be increased. In the present embodiment, the B file and the C file correspond to the interpolation stream and are one of the reproduction streams. When distinguishing the B file and the C file, the B file may be referred to as a first interpolation stream and the C file may be referred to as a second interpolation stream. In the present embodiment, the playback time of the B file is 12 minutes, and the playback time of the C file is 3 minutes. However, the reproduction times of the B and C files are not limited to the values as described above.

  More specifically, the A file includes a plurality of stream blocks having a reproduction order, that is, three stream blocks in the present embodiment. The three stream blocks are referred to as stream block (b), stream block (b), and stream block (c). These three stream blocks are stream block (b), stream block (b), and stream block (c). Played in order. The B file includes a stream block (A) and a stream block (B). The C file includes a stream block (A). When transmitting the B file, the first interpolation server 7 transmits the stream block (A) and the stream block (B) in this order. The second and first interpolation servers 7 and 8 are servers that transmit the B and C files in response to a request from the viewer, specifically, in response to a transmission request signal transmitted from the receiving terminal. If the transmission request signal is not transmitted from the terminal device 3 without the request of the user, the transmission is stopped to reduce the burden on the Internet 4.

  The still image server 9 stores a still image data file as a still image file. The still image server 9 transmits a still image file in response to a transmission request signal transmitted from the terminal device 3 in response to an arbitrary time access by the viewer. The still image server 9 is a file server for transmitting a still image for interpolation until transmission of an interpolation stream is started.

  The two types of interpolation streams and still image files for interpolating the above near-on-demand streams are based on the timing accessed by the viewer, specifically in response to a transmission request signal from the terminal device 3, Transmission and transmission stop from the servers 7, 8, 9 to the Internet 4 are switched by the switching control unit 10. Further, the server device 2 includes a switching control unit 10 that is the transmission control unit. The server device 2 is configured to be able to transmit control information including a reproduction order in which the stream blocks (A), (B), and (C) are to be reproduced.

  The viewer uses the terminal device 3 to access the broadcast station server device 2 through the Internet 4, receives playback streams and files transmitted from the servers 6 to 9, and based on control information transmitted from the broadcast station. The stream blocks included in the playback stream are played back in the order of playback and viewed as video and audio. The A, B, and C files are transmitted by the stream method. However, if the transmission time is short, the files need not be the stream method and may be transmitted by the download method. When one of the stream format and download format files is indicated, it may be referred to as reproduction information.

  FIG. 3 is a system diagram of the viewer terminal device 3. The terminal device 3 includes a transmission / reception terminal 11, a storage unit 12, a display unit 13, a switching unit 14, and an input unit 15. The terminal device 3 is, for example, a computer or a television receiver. However, it is not limited to such a thing. The transmission / reception terminal 11 serving as a reception unit and a transmission request unit has a function of receiving a reproduction stream, a still image file, and control information transmitted from the server device 2 via the Internet 4. The playback stream and still image file received by the transmission / reception terminal 11 are transmitted to the storage unit 12 and the display unit 13 via the transmission path 16. The transmission path 16 includes a direct transmission path 16a that reproduces a stream block in substantially real time, and a reproduction transmission path 16b that is recorded once by the storage unit 12 and reproduced after adjusting the start time. Based on the control information, the transmission / reception terminal 11 transmits the reproduction stream and the still image file to the display unit 13 through one of the direct transmission path 16a and the reproduction transmission path 16b.

  The storage unit 12 serving as a storage unit has a function of storing a playback stream transmitted through the playback-side transmission path 16b. The display unit 13 can reproduce the reproduction stream, display the video, and play a sound. The switching unit 14 has a function of switching a path for transmitting the reproduction stream and the still image file to the display unit 13 to either the direct transmission path 16a or the reproduction transmission path 16b based on the control information. The display unit 13 serving as a playback unit is connected to the downstream side in the direction in which the playback stream and the still image file are transmitted from the switching unit 14. The input unit 15 is configured to allow the viewer to input. The input unit 15 is configured for the viewer to input when requesting transmission of a playback stream, that is, when the viewer wants to watch a program. The transmission / reception terminal 11 transmits a transmission request signal to the server device 2 via the Internet 4 based on the input to the input unit 15.

  FIG. 4 is a timing chart of the near on-demand stream and the two interpolation streams. In FIG. 4, time is shown on the horizontal axis. FIG. 4 shows a timing chart of the near on-demand stream, the first interpolation stream, and the second interpolation stream in order from the page. Below, the outline | summary of the usage of a 1st and 2nd interpolation stream is demonstrated. The near-on-demand stream, the first interpolated stream including the higher-order stream blocks (A) and (B) in the near-on-demand stream, and the near-on-demand stream in the highest playback order. There are two interpolated streams of the second interpolated stream including stream block (a). The near on-demand stream, the first interpolation stream, and the second interpolation stream are transmitted repeatedly in succession. Transmission of the near on-demand stream, the first interpolation stream, and the second interpolation stream is started in the order of the near on-demand stream, the second interpolation stream, and the first interpolation stream from the servers 6, 7, and 8. Yes.

  When a transmission request signal is transmitted from the terminal device 3 and received by the server device 2 with a delay from the transmission start time at which transmission of the near on-demand stream is started, that is, a certain viewer receives a near-on-demand stream. When accessing after the start of the program, the transmission / reception terminal 11 receives one of the near on-demand stream, the first interpolation stream, and the second interpolation stream according to the access time. In the following description, when the viewer accesses the server apparatus 2 later than the time when transmission starts from the first interpolation stream, the second interpolation stream is transmitted from the server apparatus 2, and the stream block surrounded by the solid line shown in FIG. ) (See (3) in FIG. 4) the case where viewing starts from the beginning will be described.

  When the reproduction of the stream block (b) of the second interpolation stream received by the transmission / reception terminal 11 is completed, the stream block (b) (b) in FIG. (See 2)) and continue playback from the beginning. When the reproduction of the stream block (b) is completed, the stream block (c) is reproduced by changing to the head of the stream block (c) of the near on-demand stream indicated by the arrow A2 in FIG. As a result, the contents of all remaining programs are reproduced.

  When the stream blocks (a) to (c) are reproduced in this way, transmission of the stream block (b) in the first interpolation stream is started during the reproduction of the stream block (a). When receiving the stream block (b) of the first interpolation stream, the terminal device 3 starts storing the stream block (b), and stores the first hatched portion 21 shown in FIG. 4 in the stream block (b). Stored in section 12. After the reproduction of the stream block (a) is completed, the stream block (b) stored in the storage unit 12 is reproduced from the head by the display unit 13 and is continuously stored. The storage of the stream block (b) is continued until the last part of the stream block (b), and the stored stream block (b) is erased when reproduced. Therefore, in (3) of FIG. 4, with the passage of time, the first hatched portion 21 indicating the portion that has not been reproduced and is stored in the storage unit 12 moves to the right.

  Similarly, when switching from the interpolated stream 1 to the near on-demand stream, transmission of the stream block (c) in the near on-demand stream is started during the reproduction of the stream block (b). When the terminal device 3 receives the stream block (c) of the near on-demand stream, the terminal device 3 starts storing the stream block (c), and the second shaded portion 22 shown in FIG. Store in the storage unit 12. After the reproduction of the stream block (b) is completed, the stream block (c) stored in the storage unit 12 is reproduced from the head by the display unit 13 and is continuously stored. The storage of the stream block (b) is continued until the last part of the stream block (b), and the stored stream block (b) is erased when reproduced. Therefore, in (2) of FIG. 4, with the passage of time, the second hatched portion 22 indicating the portion that has not been reproduced and is stored in the storage unit 12 moves to the right. Playback is delayed from the previously memorized operation and viewed to the end of the program.

  The first and second hatched portions 21 and 22 in FIG. 4 indicate the difference in operation time between the operation of preceding storage and the operation of reproduction. When an access is made after the start of the program, the program of the near on-demand stream is increased by this operation time difference. Viewing will be completed later than the end.

  FIG. 5 is a diagram showing a timing chart of a plurality of near-on-demand streams. Near-on-demand broadcasting that transmits only such near-on-demand streams is a conventional technique. The main server 6 transmits a plurality of near-on-demand streams as shown in FIG. The main server 6 starts transmission of each near-on-demand stream at a main transmission start time having a predetermined main transmission time interval. The main transmission time interval is, for example, the file length of the first interpolation stream, that is, the playback time of the B file. However, it is not limited to this time interval. In the present embodiment, the near-on-demand stream is a program stream having a playback time of 60 minutes. The main transmission time interval is 12 minutes, and five near-on-demand streams are transmitted from the main server 6 while shifting the time at intervals of 12 minutes. Therefore, the main transmission start times are 0 minutes, 12 minutes, 24 minutes, 36 minutes and 48 minutes. Each near-on-demand stream continues to transmit the near-on-demand stream with the same contents continuously after the 60-minute transmission of the A file, so the near-on-demand stream is transmitted continuously for 24 hours. Is done. Since each near on-demand stream having the same content is transmitted at a time interval of 12 minutes, the viewer can receive a maximum of 12 even if only these five near-on-demand streams can be received. If you wait for a minute, you can play and watch from the beginning of the program.

  FIG. 6 shows a timing chart of the near on-demand stream and the first interpolation stream. In the following, a near-on-demand stream group composed of a plurality of near-on-demand streams and a first interpolation stream group composed of a plurality of first interpolation streams are used, and two stages composed of such two stream groups are used. The case of the configuration will be described. In the present embodiment, the main server 6 transmits five near-on-demand streams, the main transmission time interval is 12 minutes, the main transmission start time is 0 minutes, 12 as in the case of FIG. Minutes, 24 minutes, 36 minutes and 48 minutes. Actually, since each near-on-demand stream is continuously repeated, the main transmission start time is 12 × α minutes. Here, α is 0 and a positive integer. Below, for convenience, 0 minutes-60 minutes are demonstrated. The near on-demand streams transmitted at 0 minutes, 12 minutes, 24 minutes, 36 minutes, and 48 minutes are referred to as near on demand streams a1, a2, a3, a4, and a5, respectively.

  The first interpolation server 7 transmits 11 first interpolation streams. The first interpolation server 7 starts transmission at a plurality of sub-transmission start times different from the main transmission start time and at predetermined sub-transmission time intervals. By determining the sub-transmission time interval, the longest time that the viewer should wait is determined. In this embodiment, the sub-transmission time interval is 1 minute, and the sub-transmission start time is 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, based on the main transmission start time of 0 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes and 11 minutes. Actually, the sub-transmission start time is 1 × β minutes, and β is a positive integer excluding multiples of 12. The sub-transmission start time is the first interpolation stream b1, b2, b3, b4, b5, b6, b7, b8 in the order of the time when transmission starts for the first interpolation stream transmitted between 1 minute and 11 minutes. , B9, b10 and b11, respectively. In addition, the reproduction time of the B file repeatedly transmitted in the first interpolation stream is 12 minutes in the present embodiment.

  Hereinafter, the operation of the near-on-demand broadcast system 1 in the case of the two-stage configuration will be described. Hereinafter, in order to simplify the description, a case where the main transmission start time 0 minutes coincides with the hour will be described. However, it is not limited to matching. When the viewer accesses the server device 2 at 00:00 on the hour, the control information is transmitted to the terminal device 3, and then the first near-on-demand stream a1 in the first stage is transmitted to the terminal device 3. The Based on the control information, the terminal device 3 receives the near-on-demand stream a1 at the transmission / reception terminal 11, transmits it to the display unit 13 via the direct transmission path 16b, and reproduces it on the display unit 13. As a result, the near-on-demand stream a <b> 1 is reproduced and the viewer can view it on the display unit 13. Similarly, when accessing 12 minutes, 24 minutes, 36 minutes, and 48 minutes 00 seconds, as with the case of accessing the server device 2 at 00 hours 00 seconds on the hour, other near-on-demand on the first stage Any one of the streams a2, a3, a4, and a5 is reproduced, and the viewer can immediately view the stream.

  Next, when the access is made within the hour 00 minutes and less than 1 minute, the still image file is transmitted together with the control information indicating that the still image should be displayed, and the display unit 13 reproduces the still image file. A still image is displayed. The time at which the first interpolation stream is transmitted, for example, a state in which a still image is displayed continues for one minute, and then the first first interpolation stream b1 in the second stage is transmitted. In the case where the access is made by other than the regular minutes, the server device 2 transmits the still image file and the control information to the terminal device in response to the access, but this description is omitted below. When accessing 1 minute, the control information is transmitted, and then the first interpolation stream b1 is transmitted. Thereafter, the terminal device 3 receives the first interpolation stream b1 based on the control information, and transmits it to the display unit 13 via the direct transmission path 16b. In the display unit 13, the first interpolation stream, which is a B file of a portion from the first 0 minutes to 12 minutes of the near on-demand stream, is played back, and the viewer can view it. While the first interpolated stream is being reproduced, a near-on-demand stream a1 including a stream block (c) that is a portion to be reproduced after 12 minutes from the start of transmission is transmitted from the main server 6. . Therefore, the terminal device 3 can store the stream block (c) in the near on-demand stream a1. When transmission of the stream block (c) in the near on-demand stream a1 is started, the terminal device 3 starts receiving the stream block (c) based on the control information, and stores the stream in the storage unit 12. Start storing block (c).

  Next, when viewing of the first interpolation stream b1 ends (after 13 minutes), the terminal device 3 changes the transmission path 16 to which the switching unit 14 is connected to the display unit 13 to the reproduction side transmission path 16b based on the control information. The display unit 13 reproduces the stream block (c) stored in the storage unit 12 from the beginning to the end. In this case, the storage unit 12 continues to record a portion that is one minute ahead of the portion that is being reproduced on the display unit 13, so that the state of reproduction and storage remains unchanged from the first time 13 minutes to the last time 61 minutes. You can continue watching. The method of storing information to be reproduced in advance and reproducing the information stored thereafter is a so-called chasing reproduction method.

  Similarly, when the time when the server apparatus 2 is accessed exceeds 11 minutes and is 11 minutes or less, the second one of the remaining first interpolated streams b2 to b11 in the second stage is selected according to the access time. One interpolation stream is reproduced. The terminal device 3 stores the stream block (c) of the near on-demand stream a1 transmitted from the main server 6 while the first interpolation stream is being reproduced, in the storage unit 12 based on the control information. After the reproduction of the first interpolation stream is completed, the stream block (c) is reproduced to the end by chasing reproduction based on the control information.

  When the server apparatus 2 is accessed by 12 minutes after 11 minutes, the state where the still image is displayed continues for 12 minutes, and the terminal apparatus 3 The on-demand stream a2 is received and the near-on-demand stream a2 is reproduced.

  When the server device 2 is accessed for more than 12 minutes and for 23 minutes or less, the terminal device 3 determines that the access time exceeds 13 minutes and is 11 minutes or less, depending on the accessed time. Any one of the first interpolation streams transmitted from 1 to 23 minutes is reproduced. Next, the stream block (c) included in the near on-demand stream a2 is received and stored, and after the reproduction of the B file, the stream block (c) is followed and reproduced.

  Similarly, when the accessed time exceeds 23 minutes, the terminal device 3 receives and reproduces the near on-demand stream and the first interpolation stream. When reproducing the first interpolation stream, the stream block (c) included in the near on-demand stream is chased and reproduced in the same manner as described above. Thus, the server device 2 and the terminal device 3 operate in substantially the same manner as in the case of 0 minute or more and 23 or less. Therefore, the detailed description of the operation of the near-on-demand broadcast system 1 when it exceeds 23 minutes will be omitted with reference to the above description.

  If the near-on-demand stream and the first interpolation stream are transmitted in this way, no matter what time the viewer accesses the server device 2, if the user waits for a maximum of 1 minute (still image viewing), the program starts and ends. Can be viewed.

  By adding 11 first interpolated streams at 1 minute intervals to 5 near-on-demand streams at 12 minute intervals in the first stage, a maximum waiting time of 12 minutes is reduced to a maximum waiting time of 1 minute. Shortened. If the near-on-demand broadcasting of this 60-minute program is to be started in a one-stage configuration with only one near-on-demand stream group, transmission of 60 near-on-demand streams must be performed. However, this is an excellent method for reducing the number of streams from 60 playback streams to a total of 16 playback streams by using a two-stage configuration of a near on-demand stream group and a first interpolation stream group. Hereinafter, a method for further reducing the number of streams of the 11 additional first interpolation streams will be described.

  FIG. 7 shows a timing chart of the near on-demand stream and the interpolation stream. In the following, a near-on-demand stream group consisting of a plurality of near-on-demand streams, a first interpolation stream group consisting of a plurality of first interpolation streams, and a second interpolation stream group consisting of a plurality of second streams A case of such a three-stage configuration composed of three stream groups will be described. Regarding the operation of the near-on-demand broadcasting system 1, the two-stage configuration shown in FIG. 6 is further advanced to a three-stage configuration. The principle of operation is the same as in the case of the two-stage configuration shown in FIG.

  In the present embodiment, five near-on-demand streams in the first stage are transmitted from the main server 6. For example, the main transmission time interval is the file length of the first interpolation stream. In the present embodiment, the main transmission time interval is 12 minutes, and the main transmission start time is 12 × α minutes. Hereinafter, as in the case of the two-stage configuration, a description will be given of 0 minutes to 60 minutes. Next, the first interpolation stream at the second stage is not changed from the B file, but the number of streams transmitted from the first interpolation server 7 is reduced to three. The first sub-transmission time interval, which is the time interval at which the second-stage first interpolation stream is transmitted, is, for example, the file length of the second interpolation stream, that is, the reproduction time of the C file. The sub-transmission time interval is 3 minutes. The first sub-transmission start time of the first interpolation stream at the second stage is 3 minutes at the beginning to substitute the head part of the first near-on-demand stream at the first stage, and 6 minutes and 9 minutes. in the process of. Actually, the first transmission start time is 3 × γ minutes, and γ is a positive integer excluding multiples of 4.

  The newly added second interpolation stream of the third stage is transmitted from the second interpolation server 8, and the transmission is started at the second sub transmission start time with a predetermined second sub transmission time interval. . The second interpolation stream includes the near on-demand stream and the first stream block (a) of the first interpolation stream, and is used to set the transmission interval of the stream block (a) to 1 minute. Two second interpolation streams c1 and c2 are transmitted from the second interpolation server. The second sub transmission time interval is the longest time that the viewer should wait for viewing. In the present embodiment, the second sub transmission time interval is determined as 1 minute, and the second sub transmission start time is δ minutes. δ is a positive integer excluding multiples of 3.

  Since the operation of the near-on-demand broadcasting system 1 is basically the same as that in the case of the two-stage configuration, the operation similar to that in the case of the two-stage configuration is simply referred to the description in the case of the two-stage configuration. The differences will be described in detail. When the viewer accesses 0 minutes, 12 minutes... 12 × α minutes, playback starts from the top of the first near-on-demand stream. When 3 minutes, 6 minutes, 9 minutes, ... 3xγ minutes are accessed, after playing from the beginning of the first interpolation stream of the second stage, the stream block (c) of the first near-on-demand stream of the first stage Change to, and play after chasing. When accessing 1 minute, 2 minutes, 4 minutes, 5 minutes,..., Minutes, the control information is transmitted from the server device 2, and then the newly added second stage second interpolation stream is transmitted. The terminal device 3 receives the second interpolation stream, transmits the received second interpolation stream to the display unit 13 via the direct transmission path 16a, and reproduces it on the display unit 13. While the second interpolation stream is being reproduced, the first interpolation server 7 is transmitted from the first interpolation server 7 including a stream block (b) that is a portion to be reproduced after 3 minutes from the start of transmission. . Therefore, the terminal device 3 can receive and store the stream block (b) in the first interpolation stream. When transmission of the stream block (b) in the first interpolation stream is started, the terminal device 3 starts receiving the stream block (b) based on the control information, and stores the stream block (b) in the storage unit 12. ) Starts to memorize.

  Next, when viewing of the second interpolation stream ends, the terminal device 3 switches the transmission path 16 connected to the display section 13 to the reproduction-side transmission path 16b based on the control information, and continues to the storage section 12. Are reproduced on the display unit 13 from the beginning to the end. In other words, the terminal device 3 changes to the stream block (b) of the first interpolation stream at the second stage and performs follow-up reproduction. While chasing and reproducing the stream block (b), a near-on-demand stream including the stream block (c) that is a part to be reproduced after 12 minutes from the start of transmission is transmitted from the main server 6. . The terminal device 3 is received by the transmission / reception terminal 11 and stored in the storage unit 12 as in the case of the stream block (b). After the reproduction of the stream block (b) is completed, the stream block (c) of the first near-on-demand stream is changed to continue the chase reproduction.

  When accessed at a time other than a minute, the server device 2 transmits a still image file together with control information. In the terminal device 3, the still image file is reproduced on the display unit 13 until the minute is reached, and the still image is displayed. When it becomes a noon, the near-on-demand broadcasting system 1 performs the same operation as when accessing the noon time. For example, when 1 minute and 30 seconds are accessed, a still image is displayed on the display unit 13 until 2 minutes, and then the second interpolation stream is received and reproduced.

  Even in such a three-stage configuration, as in the case of the two-stage configuration, the viewer can watch with a maximum waiting time of 1 minute no matter what time of access. By using the three-stage near-on-demand stream, the first interpolation stream, and the second interpolation stream, the first and second three-stage configurations are performed for 11 streams of the first interpolation stream having the two-stage structure. The total number of 2 interpolated streams is reduced to 5. As a result, even when the number of near-on-demand streams is five, the number of streams becomes ten, and the number of streams in the near-on-demand broadcast system 1 as a whole is reduced. By reducing the number of streams, the transmission amount per unit time can be suppressed while maintaining the interval at which the transmission of the stream block (A) with the highest playback order is started.

  FIG. 8 is a flowchart showing the processing operation of the server device 2 in the case of a three-stage configuration. The processing operation of the server device 2 will be described with reference to the flowchart of FIG. The server device 2 executes the processing of the flowchart shown in FIG. 8 by executing the program. Hereinafter, for convenience of explanation, the near on-demand stream may be referred to as A stream, the first interpolation stream as B stream, and the second interpolation stream as C stream. In addition, the access timing, that is, the access time, which is the access time, is set to t0, the corresponding place is set to tT, and the second is set to tS. Therefore, the time t0 is expressed as tT minutes tS seconds. In addition, the transmission start intervals of the A stream, the B stream, and the C stream are assumed to be X1, X2, and X3. The file lengths of the A file, the B file, and the C file, that is, the reproduction times are referred to as A, B, and C. The unit of the reproduction time is, for example, second.

  When the viewer accesses the server device 2 at time t0, the process is started, and the process proceeds to step s1. In step s1, the access time t0 is stored. When the access time is stored, the process proceeds to step s2. In step s2, server information is transmitted from the server device 2. The server information includes transmission start intervals X1, X2, and X3 of each stream. When the server information is transmitted, the process proceeds from step s2 to step s3.

  In step s3, it is determined whether or not the second place tS = 0 is satisfied. If it is determined that tS ≠ 0, the process proceeds to step s4, and if it is determined that tS = 0, the process proceeds to step s5. In step s4, the still image file is transmitted from the server device 2 until the minute becomes equal. When it becomes a regular part, the process proceeds to step s5. In step s5, a remainder P obtained by dividing the minute tT by the B stream transmission start interval X2 is obtained. When the remainder P is obtained, the process proceeds to step s6. In step s6, it is determined whether or not the remainder P = 0 is satisfied. If it is determined that P = 0 is satisfied, the process proceeds to step s7.

  In step s7, control information indicating that the A stream should be received from the server apparatus 2 and transmitted to the terminal apparatus 3 is transmitted. From the server apparatus 2, transmission of the A stream is started at a plurality of main transmission start times having a main transmission time interval. When the control information is transmitted, the process ends.

  If it is determined in step s6 that the remainder P ≠ 0, the process proceeds to step s8. In step s8, a quotient Q and a remainder R obtained by dividing the remainder P by the transmission start interval X3 of the C stream are obtained. When the quotient Q and the remainder R are obtained, the process proceeds to step s9. In step s9, the quotient Q obtained in step s8 is transmitted to the terminal device 3. When the quotient Q is transmitted, the process proceeds to step s10. In step s10, it is determined whether or not the remainder R obtained in step s8 satisfies R = 0. If it is determined that the remainder R = 0 is satisfied, the process proceeds to step s11.

  In step s11, control information indicating that the B stream should be received and reproduced from the server apparatus 2 to the terminal apparatus 3 at the first sub-transmission start time is transmitted, and then transmission of the B stream from the server apparatus 2 is started. When transmission of the B stream is started, the process proceeds to step s12. In step s12, it is determined whether or not the transmission of the B stream is completed. If it is determined that the transmission of the B stream is not completed and has not been completed, the process returns to step s12 after a predetermined time has elapsed, and it is determined whether or not the transmission of the B stream is completed and completed again. If it is determined in step 13 that the transmission of the B stream has been completed, the process proceeds to step s13. In step s13, transmission of the B stream is stopped. When transmission of the B stream is stopped, the process ends.

  If it is determined in step s10 that the remainder R ≠ 0 obtained in step s8, the process proceeds to step s14. In step s14, transmission of the C stream from the server device 2 is started. When transmission of the C stream is started, the process proceeds to step s15. In step s15, control information indicating that the B stream should be received and reproduced from the server apparatus 2 to the terminal apparatus 3 at the first sub transmission start time is transmitted, and then transmission of the B stream from the server apparatus 2 is started. When transmission of the B stream is started, the process proceeds to step s16. In step s16, it is determined whether or not transmission of the C stream is completed. If it is determined that the transmission of the C stream is not completed and has not been completed, the process returns to step s16 after a predetermined time has elapsed, and it is determined again whether or not the transmission of the C stream has been completed and completed. If it is determined in step 17 that transmission of the C stream has been completed, the process proceeds to step s17. In step s17, transmission of the C stream is stopped. When the transmission of the C stream is stopped, the process proceeds to step s12.

  The process of starting transmission of the A stream at the main transmission start time corresponds to the main transmission process, and the process of starting transmission of the B stream or C stream in steps s11, s14, and s15 corresponds to the sub transmission process.

  FIG. 9 is a flowchart showing a recording and playback control procedure of the terminal device 3 having a three-stage configuration. The control procedure of the terminal device 3 will be described with reference to the flowchart of FIG. The terminal device 3 executes the processing of the flowchart shown in FIG. 9 by executing the program. When the viewer operates the input unit 15 to start viewing, the process starts, and the process proceeds to step t1. In step t 1, based on the operation of the input unit 15, a transmission request signal including the viewing start time t 0 that is the access time t 0 is transmitted from the terminal device 3 to the server device 2. When the transmission request signal is transmitted, the process proceeds to step t2. In step t2, server information transmitted from the server device 2 is stored. When the server information is stored, the process proceeds to step t3. In step t3, it is determined whether or not the access time t0 is a minute, that is, whether or not tT = 0 is satisfied. If it is determined that tT ≠ 0, the process proceeds to step t4, and if it is determined that tT = 0, the process proceeds to step t5.

  In step t4, the still image file transmitted from the server device 2 is received, the still image file is reproduced until it becomes a proper part, and the still image is displayed on the display unit 13. When it becomes a regular part, the process proceeds to step s5. In step t5, it is determined whether or not control information indicating that the A stream should be received and reproduced has been received. If it is determined that the control information has been received, the process proceeds to step t6. In step t6, the A stream transmitted from the server device 2 is received, transmitted to the display unit 13 via the direct transmission path 16a, and reproduction is started on the display unit 13. When the reproduction of the A stream is started, the process proceeds to step t7. In step t7, it is determined whether or not the reproduction of the A stream has been completed. If it is determined that the playback of the A stream has not been completed and has not ended, the process returns to step t7 after a predetermined time has elapsed, and it is determined again whether or not the playback of the A stream has been completed and ended. If it is determined that the reproduction of the A stream has been completed, the process ends.

  If it is determined in step t5 that control information indicating that the A stream should be received and played back has not been received, the process proceeds to step t8. In step t8, the quotient Q transmitted from the server apparatus 2 is stored, and it is determined whether or not this quotient Q satisfies Q = 0. When the quotient Q = 0 is satisfied, the process proceeds to step t9. In step t9, when transmission of a portion of the A stream that starts C minutes after the transmission is started, that is, transmission of the stream blocks (B) and (C) of the A stream is started, the stream block ( (B) and (c) are set to start storing. Thereafter, when transmission of stream blocks (B) and (C) of the A stream is started, storage of the stream blocks (B) and (C) is started. When set, the process proceeds to step t10.

  In step t10, the C stream transmitted from the server device 2 is received, transmitted to the display unit 13 via the direct transmission path 16a, and reproduction is started on the display unit 13. When the reproduction of the C stream is started, the process proceeds to step t11. In step t11, it is determined whether or not the reproduction of the C stream has been completed. If it is determined that the reproduction of the C stream is not completed and has not been completed, the process returns to step t11 after a predetermined time has elapsed, and it is determined again whether or not the reproduction of the C stream has been completed and completed. If it is determined that the reproduction of the C stream has been completed, the process proceeds to step t12. At step t12, the stream blocks (b) and (c) stored in the storage unit 12 are transmitted to the display unit 13 via the playback side transmission path 16b, and playback is started on the display unit 13, that is, chasing playback is started. To do. When the chase playback of the stream block (c) is started, the process proceeds to step t7.

  If it is determined in step t8 that the quotient Q ≠ 0, the process proceeds to step t13. In step t13, when transmission of the A stream starts after B minutes from the start of transmission, that is, when transmission of the stream block (c) of the A stream is started, the stream block (c) of the A stream is stored. Is set to start. Thereafter, when transmission of the stream block (c) of the A stream is started, storage of the stream block (c) is started. When set, the process proceeds from step t13 to step t14.

  In step t14, it is determined whether or not control information indicating that the B stream should be received and reproduced has been received. If it is determined that the control information has been received, the process proceeds to step t15. In step t15, the B stream transmitted from the server device 2 is received, transmitted to the display unit 13 via the direct transmission path 16a, and reproduction is started on the display unit 13. When the reproduction of the B stream is started, the process proceeds to step t16. In step t16, it is determined whether or not the reproduction of the B stream has been completed. If it is determined that the reproduction of the B stream is not completed and has not been completed, the process returns to step t16 after a predetermined time has elapsed, and it is determined again whether or not the reproduction of the B stream has been completed and completed. If it is determined that the reproduction of the B stream has been completed, the process proceeds to step t17. In step t17, the stream block (c) stored in the storage unit 12 is transmitted to the display unit 13 via the playback-side transmission path 16b, and playback is started on the display unit 13, that is, chasing playback is started. When the chase playback of the stream block (c) is started, the process proceeds to step t7.

  If it is determined in step t14 that control information indicating that the B stream should be received and played back has not been received, the process proceeds to step t18. In step t18, when transmission of a portion of the B stream that starts C minutes after the start of transmission, that is, transmission of the stream block (c) of the B stream is started, the stream block (c) of the B stream is stored. Is set to start. Thereafter, when transmission of the stream block (b) of the B stream is started, storage of the stream block (b) is started. When set, the process proceeds to step t19.

  In step t19, the C stream transmitted from the server device 2 is received, transmitted to the display unit 13 via the direct transmission path 16a, and reproduction is started on the display unit 13. When reproduction of the C stream is started, the process proceeds to step t20. In step t20, it is determined whether or not the reproduction of the C stream has been completed. If it is determined that the reproduction of the C stream is not completed and has not been completed, the process returns to step t20 after a predetermined time has elapsed, and it is determined again whether or not the reproduction of the C stream has been completed and completed. If it is determined that the reproduction of the C stream has been completed, the process proceeds to step t21. In step t21, the stream block (b) stored in the storage unit 12 is transmitted to the display unit 13 via the playback-side transmission path 16b, and playback is started on the display unit 13, that is, chasing playback is started. When the chase playback of the stream block (b) is started, the process proceeds to step t16.

  In step t6, step t9, step t13, step t15, step t18 and step t19, the process of receiving the playback stream corresponds to the receiving process. In step t9, step t13, and step t18, the process of storing at least one of the stream blocks (b) and (c) corresponds to the storage process. Furthermore, the process of reproducing the reproduction stream in step t6, step t15, step t17, step t19, and step t21 corresponds to the reproduction process.

  Since the server device 2 and the terminal device 3 of the near-on-demand broadcast system 1 operate according to the flowcharts shown in FIGS. 8 and 9, the waiting time until the viewer starts the video is less than that of the conventional technology. Near-on-demand broadcasting can be realized. Below, the effect which the near on-demand broadcasting system 1, the server apparatus 2, and the terminal device 3 show | play is demonstrated.

  According to the near on-demand broadcasting system 1 of the present embodiment, since the first and second interpolation servers 7 and 8 are included, the number of main transmission start times of the near on-demand stream is maintained. Thus, the interval at which the highest stream block (a) is transmitted in the reproduction order can be made shorter than in the conventional technique in which only the near on-demand stream is transmitted. As a result, the waiting time until the terminal device 3 receives the stream block (A) is reduced. Since the first and second interpolation streams are part of the near on-demand stream, the time during which the first and second interpolation streams are transmitted is shorter than the time during which the near on-demand stream is transmitted. Since the time during which the first and second interpolation streams are transmitted is short, the number of first sub-transmission start times that elapse between the start of transmission of one first interpolation stream and the completion of transmission is suppressed. The Also, the number of second sub-transmission start times that elapse between the start of transmission of one second interpolation stream and the completion of transmission is suppressed. As a result, the number of streams transmitted over the Internet 4 is suppressed, and the amount of transmission transmitted from the server device 2 to the Internet 4 can be suppressed. Since the transmission amount can be suppressed, the burden on the Internet 4 can be suppressed even if the sub-transmission time interval is shortened. Therefore, the sub-transmission time interval can be shortened. In addition, since transmission from the first and second interpolation servers 7 and 8 is not always performed, the minimum transmission amount transmitted from the server device 2 is smaller than that of the conventional technique.

  In the present invention, the storage unit 12 stores stream blocks (c) that are not included in the first interpolation stream and are included in the near-on-demand stream. Since the stream block (B) that is not included in the interpolation stream and included in the first interpolation stream is stored, the stream block (A), (B), and (C) is played back in the playback order in the display unit 13. can do. Accordingly, the user can use the terminal device 3 to reproduce a reproduction stream in which the interval at which the stream block (A) is transmitted is short and the transmission amount is suppressed.

  In addition, according to the near on-demand broadcast of the present embodiment, since the sub-transmission step is included, the first and second interpolation servers 7 and 8 are included, so that the number of main transmission start times of the near on-demand stream is maintained. In this state, the interval at which the highest-order stream block (A) is transmitted in the reproduction order can be made shorter than in the conventional technique in which only the near on-demand stream is transmitted. This reduces the waiting time until the stream block (A) is received. Since the first and second interpolation streams are part of the near on-demand stream, the time during which the first and second interpolation streams are transmitted is shorter than the time during which the near on-demand stream is transmitted. Since the time during which the first and second interpolation streams are transmitted is short, the number of first sub-transmission start times that elapse between the start of transmission of one first interpolation stream and the completion of transmission is suppressed. The Also, the number of second sub-transmission start times that elapse between the start of transmission of one second interpolation stream and the completion of transmission is suppressed. As a result, the number of streams transmitted over the Internet 4 is suppressed, and the amount of transmission transmitted from the server device 2 to the Internet 4 can be suppressed. Since the transmission amount can be suppressed, the burden on the Internet 4 can be suppressed even if the sub-transmission time interval is shortened. Therefore, the sub-transmission time interval can be shortened. In addition, since transmission from the first and second interpolation servers 7 and 8 is not always performed, the minimum transmission amount transmitted from the server device 2 is smaller than that of the conventional technique. When the transmission request signal is transmitted, transmission from the first and second interpolation servers 7 and 8 is not always performed, and the minimum transmission amount transmitted from the server device 2 is also smaller than that of the conventional technique. Few.

  In the present invention, stream blocks (c) that are not included in the first interpolation stream in the storing step and are included in the near on-demand stream are stored, and similarly, the second interpolation stream is stored. Since the stream block (b) included in the first interpolation stream is not included in the first interpolation stream, the playback stream can be played back in the playback order in the playback process. Accordingly, the user can use the terminal device 3 to reproduce a reproduction stream in which the interval at which the stream block (A) is transmitted is short and the transmission amount is suppressed.

  According to the program of the server device 2 of the present embodiment, the server device 2 that is communicably connected to the terminal device 3 via the Internet can execute the processing operation shown in the flowchart of FIG. With this technique, it is possible to realize the server device 2 in which the stream block (A) transmission interval is short and the transmission amount is suppressed.

  Next, optimization of the number of streams will be described. Here, the optimization of the number of streams in each stage for reducing the total number of streams in near-on-demand broadcasting for shortening the waiting time will be described.

  Now, the file lengths of the A file, the B file, and the C file are A, B, and C as shown in FIG. 7, and the transmission time when the highest-level stream block, in this embodiment, the stream block (A) is transmitted. Let the interval be D. At this time, A to D have a relationship as shown in Expression (1).

第１項のＡ／Ｂは、１段目のニア・オンデマンドストリームのストリーム数を表し、第２項の（Ｂ／Ｃ−１）は２段目の第１補間ストリームのストリーム数を表し、Ｃ／Ｄ−１は３段目の第２補間ストリームのストリーム数を表している。総ストリーム数Ｘは、式（１）を充足しつつ、式（２）で与えられる。 In addition, the total number of streams X is obtained by Expression (2).

A / B in the first term represents the number of streams in the first-stage near-on-demand stream, and (B / C-1) in the second term represents the number of streams in the second-stage first interpolation stream, C / D-1 represents the number of streams of the second interpolation stream at the third stage. The total number of streams X is given by equation (2) while satisfying equation (1).

  The optimization for minimizing the total number of streams X in equation (2) while maintaining the relationship of equation (1) will be described. When A, B, C, and D> 0, the relation of Expression (3) is established from the arithmetic geometric mean theorem.

（Ａ／Ｂ）＝（Ｂ／Ｃ）＝（Ｃ／Ｄ）となる場合、式（３）の左辺と右辺とが等しくなり、（Ａ／Ｂ）＝（Ｂ／Ｃ）＝（Ｃ／Ｄ）のとき、式（３）の左辺は、最小値となる。したがって総ストリーム数Ｘは、式（５）の関係を有する。 When Expression (2) is substituted into Expression (3) and expanded, Expression (4) is given.

When (A / B) = (B / C) = (C / D), the left side and the right side of Equation (3) are equal, and (A / B) = (B / C) = (C / D) ), The left side of Equation (3) is the minimum value. Therefore, the total number of streams X has the relationship of equation (5).

  The file lengths A, B, and C and the transmission time interval D need to satisfy the following conditions. (1) The total number of streams X and the number of streams in each stage (A / B), (B / C-1), (C / D-1) are integers, and (2) the file length of each stage is It is necessary to be an integer and to satisfy (3) Equation (1). The file lengths A, B, and C and the transmission time interval D are determined so that the conditions (1) to (3) are satisfied and the total number of streams X is minimized. In particular, the playback time of the first and second interpolation streams is preferably a divisor of the playback time of the near on-demand stream.

Furthermore, this relational expression is generalized to consider near-on-demand broadcasting with a k-stage configuration. Assuming that the transmission intervals of each stage are a ₁ , a ₂ , a ₃ ,..., A _k−1 , a _k , Expression (6) and Expression (7) are given.

したがって、ｋ段構成の場合、条件（３）は、式（８）を充足することであり、条件（１）〜（３）を充足し、かつ総ストリーム数Ｘが最小になるように、ファイル長Ａ，Ｂ，Ｃおよび送信時間間隔Ｄの最適解を演算し、これらの値を決定する。特に補間ストリームの再生時間が、ニア・オンデマンドストリームの再生時間の約数であることが好ましい。またファイル長Ａ、Ｂ、Ｃおよび送信時間間隔Ｄは、その単位が「分」および「秒」のいずれかである。 When the minimum total number of streams X in the k-stage configuration is calculated based on the arithmetic geometric mean theorem, it is given by equation (8).

Therefore, in the case of the k-stage configuration, the condition (3) is to satisfy the equation (8), the file is so that the conditions (1) to (3) are satisfied and the total number of streams X is minimized. The optimum solutions of the lengths A, B, C and the transmission time interval D are calculated, and these values are determined. In particular, the playback time of the interpolation stream is preferably a divisor of the playback time of the near on-demand stream. The unit of the file lengths A, B, C and the transmission time interval D is either “minute” or “second”.

  Table 1 shows a calculation example in which a 60-minute program is interpolated to approximately 10 seconds, which can be regarded as on-demand broadcasting, and is optimized so as to satisfy the conditions (1) to (3). The unit of the transmission time interval D is “minute”, and the second to fifth stages of computation are performed so that D is an integer. The vertical axis indicates the number of stages, the horizontal axis indicates the number of streams in each stage, the main transmission start interval (near-on-demand interval), the total number of streams excluding the near-on-demand stream (interpolated stream), the total number of streams, and the transmission bits Shown in order of rate. Although the total number of streams decreases as the number of stages increases, the rate of reduction of the total number of streams is small for increasing complexity as the number of stages increases. In this example, 3 stages and 4 stages are preferable. The transmission bit rate is H.264. This is an example of a transmission bit rate required in the case of on-demand broadcasting using a 10 Mbps HDTV compressed with a H.264 codec or the like. The minimum bit rate is based on the first-stage near-on-demand stream having a fixed bit rate. In other words, this is the transmission bit rate when the interpolation stream after the second stage is not transmitted. The interpolated stream has a bit rate with a variable transmission amount and is not constant depending on the viewer's access. Therefore, the table represents the bit rate from the minimum to the maximum.

  According to the near on-demand broadcasting system of the present embodiment, the transmission bit rate can be suppressed and the burden on the Internet 4 can be suppressed even at a transmission start interval of 10 seconds, for example. As a result, provision to a large number of viewers is possible, and it is possible to prevent the video and sound from being stopped during the viewing and to allow the viewers to view comfortably. As described above, the near-on-demand broadcasting system 1 has an excellent effect particularly in near-on-demand broadcasting.

  In the present embodiment, the control information is transmitted immediately before each reproduction stream is transmitted, but may be transmitted in advance. For example, when the server apparatus 2 receives a transmission request signal, control information including a timing chart indicating the order of file reception and reproduction may be transmitted in advance. The terminal device 3 should just receive and reproduce | regenerate according to this timing chart. Further, when the terminal device 3 is turned on at the beginning of the month or day, control information including a timing chart indicating the reception and reproduction order for all programs is transmitted, and the storage unit of the terminal device 3 is transmitted. 12 may be stored. In this case, the terminal device 3 controls each component based on the control information stored in the storage unit 12, and receives and reproduces the reproduction stream. By receiving control information in advance in this way, transfer and reception between streams can be performed smoothly.

  In the present embodiment, transmission of the stream block (A) is started based on the transmission request signal transmitted from the terminal device 3, but the present invention is not necessarily limited to such a configuration. For example, the stream block having the highest playback order of a plurality of programs may be transmitted in advance to the terminal device 3 as a download method file and stored in the storage unit 12. The viewer uses the input unit 15 to select the highest stream block of the program that the user wants to view and reproduces this stream block on the display unit 13. Further, when selected, the terminal device 3 transmits a transmission request signal to the server device 2. The server device 2 transmits a stream block to be reproduced next, and the terminal device 3 receives and reproduces the stream block. Such near-on-demand broadcasting may be used.

  In this embodiment, it is near-on-demand broadcasting, and video and sound information is distributed. However, the information to be distributed may be character data or sound information, and is not limited. .

  In this embodiment, the control information and the interpolation stream are separate, but the control information may be included in the head part of the interpolation stream, and the control information can be acquired by reproducing the interpolation stream. .

  In the present embodiment, the main transmission start time, the sub transmission start time, the first sub transmission start time, and the second sub transmission start time are equally spaced. May be. The main transmission time interval, the sub transmission time interval, the first sub transmission time interval, and the second sub transmission time interval shown in the present embodiment are merely examples, and may be set to desired times.

The following embodiments are possible for the present invention.
An information providing system including an information providing device and a terminal device that is communicably connected to the information providing device via a communication network, wherein the information providing device transmits reproduction information that can be reproduced by the terminal device. Transmission means, main reproduction information which is one piece of reproduction information, and main reproduction information including a plurality of information blocks having a reproduction order is stored, and a plurality of main reproduction intervals with a predetermined main transmission time interval are stored. A main transmission unit that starts transmission of the reproduction information such that each information block is transmitted in the order of reproduction at each transmission start time, and sub reproduction information that is one piece of reproduction information, and is included in the main reproduction information. A plurality of sub-transmissions that are partial information blocks and store sub-reproduction information including one or a plurality of information blocks whose reproduction order is higher, differ from the main transmission start time, and have predetermined sub-transmission time intervals Based on a transmission request signal transmitted from a terminal device, and a transmission means including a sub-transmission unit capable of starting transmission of the sub-reproduction information so that each information block is transmitted in the reproduction order at each start time And a transmission control unit that causes the sub-transmission unit to start transmission of the sub-reproduction information, and the terminal device transmits the request transmission unit that transmits a transmission request signal to the information providing device based on the input, and is transmitted from the information providing device. Receiving means capable of receiving reproduction information, and when receiving one piece of reproduction information, if another piece of reproduction information including an information block not included in the piece of reproduction information is received, it is included in the one piece of reproduction information. A storage unit that stores information blocks that are not included and are included in the other reproduction information, and a reproduction unit that can reproduce the information blocks included in the received reproduction information in the order of reproduction. Information providing system characterized.

  According to the information providing system of the present embodiment, since the sub-transmission unit is included, the highest information block in the reproduction order is transmitted while the number of main transmission start times of the main reproduction information is maintained. The interval can be made shorter than in the case of the conventional technique in which only main reproduction information is transmitted. This reduces the waiting time until the highest information block is received. Further, since the sub reproduction information is a part of the main reproduction information, the time during which the sub reproduction information is transmitted is shorter than the time during which the main reproduction information is transmitted. Since the time during which the sub-reproduction information is transmitted is short, the number of sub-transmission start times that elapse between the start of transmission of one sub-reproduction information and the completion of transmission is suppressed. As a result, the number of sub-reproduction information transmitted through the communication line network is suppressed, and the amount of transmission transmitted from the information providing apparatus to the communication line network can be suppressed. Since the amount of transmission can be suppressed, even if the sub-transmission time interval is shortened, the burden on the communication line network can be suppressed. Therefore, the sub-transmission time interval can be shortened. In addition, since transmission from the sub-transmission unit is not always performed, the minimum transmission amount transmitted from the information providing apparatus is smaller than that of the conventional technique.

  In the information providing system, the storage means stores information blocks that are not included in one piece of playback information and are included in other playback information. Information can be reproduced. Accordingly, the user can reproduce the reproduction information in which the transmission time interval of the highest information block is short and the transmission amount is suppressed in the reproduction order using the terminal device.

  In an information providing system including an information providing device and a terminal device that is communicably connected to the information providing device via a communication line network, for each of a plurality of main transmission start times at predetermined main transmission time intervals The main reproduction information, which is main reproduction information that is one piece of reproduction information that can be reproduced by the terminal device and includes a plurality of information blocks having the reproduction order, is transmitted from the information providing apparatus in order of the reproduction order. When the transmission request signal is transmitted from the terminal device to the information providing device, the main transmission process starts at a plurality of sub-transmission start times different from the main transmission start time and at predetermined sub-transmission time intervals. Sub-reproduction information that is one of the reproduction information, a part of information blocks included in the main reproduction information, and sub-reproduction information including one or more information blocks in the upper reproduction order, A sub-transmission step for starting transmission of information blocks from the information providing device in the order of reproduction, a reception step for receiving the reproduction information transmitted from the information providing device, and one piece of reproduction information are received. When other reproduction information including an information block not included in the reproduction information is received, an information block which is an information block not included in the one reproduction information and included in the other reproduction information is transmitted to the terminal device. The information provision method characterized by including the memory | storage process which memorize | stores, and the reproduction | regeneration process by which a terminal device reproduces | regenerates the information block contained in the reproduction | regeneration information received.

  According to the information providing method of the present embodiment, since the sub-transmission step is included, the interval at which the highest-order information block is transmitted in the reproduction order with the number of transmissions of the main reproduction information being maintained is This can be made shorter than in the case of the conventional technique having only the main transmission process. This reduces the time to wait until the highest information block is received. Further, since the sub reproduction information is a part of the main reproduction information, the time during which the sub reproduction information is transmitted is shorter than the time during which the main reproduction information is transmitted. Since the time during which the sub-reproduction information is transmitted is short, the number of sub-transmission start times that elapse between the start of transmission of one sub-reproduction information and the completion of transmission is suppressed. As a result, the number of sub-reproduction information transmitted through the communication line network is suppressed, and the amount of transmission transmitted from the information providing apparatus to the communication line network can be suppressed. Since the amount of transmission can be suppressed, even if the sub-transmission time interval is shortened, the burden on the communication line network can be suppressed. Therefore, the sub-transmission time interval can be shortened. When the transmission request signal is transmitted, transmission is started in the sub-transmission step. Therefore, transmission from the sub-transmission unit is not always performed, and the minimum transmission amount transmitted from the information providing apparatus is also the conventional technology. Less than

  In the information providing method, information blocks that are not included in one piece of reproduction information in the storage step and are included in other reproduction information are stored, so that the reproduction information is reproduced in the reproduction order in the reproduction step. Can be played. Accordingly, the user can reproduce the reproduction information in which the transmission time interval of the highest information block is short and the transmission amount is suppressed in the reproduction order using the terminal device.

1 is a system diagram showing a near-on-demand broadcast system 1. FIG. 4 is a system diagram of the server device 2. FIG. It is a systematic diagram of the terminal device 3 of the viewer. It is a figure which shows the timing chart of a near on-demand stream and two interpolation streams. It is a figure which shows the timing chart of several near-on-demand streams. The timing chart of a near on-demand stream and a 1st interpolation stream is shown. The timing chart of a near on-demand stream and an interpolation stream is shown. It is a flowchart which shows the processing operation of the server apparatus 2 in the case of 3 steps | paragraphs structure. It is a flowchart which shows the control procedure of recording and reproduction | regeneration of the terminal device 3 of 3 steps | paragraphs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Near on-demand broadcasting system 2 Server apparatus 3 Terminal apparatus 4 Internet 6 Main server 7 1st interpolation server 8 2nd interpolation server 10 Switching control part 11 Transmission / reception terminal 12 Storage part 13 Display part 17 Transmission means

Claims (4)

(A) a near-on-demand broadcast system including a server device and a terminal device that is communicably connected to the server device via an Internet network,
(B) The server device
(B1) Transmission means for transmitting a stream that can be played back by the terminal device. (B11) A main stream that is one of the streams and that includes a plurality of information blocks having a playback order is stored in advance. A main server that starts transmission of the stream so that each information block is transmitted in the order of reproduction for each of a plurality of main transmission start times with a predetermined main transmission time interval;
(B12) An interpolation stream, which is one of the streams, is a partial information block included in the main stream, and stores an interpolation stream including one or a plurality of information blocks with higher playback order, and the main transmission start time And an interpolation server capable of starting transmission of the interpolated stream so that each information block is transmitted in the order of reproduction at each of a plurality of sub-transmission start times separated by a predetermined sub-transmission time interval. A transmission means;
(B2) transmission control means for causing the interpolation server to start transmission of the interpolation stream based on a transmission request signal transmitted from the terminal device,
(C) The terminal device
(C1) request transmission means for transmitting a transmission request signal to the server device based on the input;
(C2) receiving means capable of receiving a stream transmitted from the server device;
(C3) When one stream is received and another stream including an information block not included in the stream is received, the information block is not included in the one stream and the other stream Storage means for storing the included information blocks;
(C4) A near-on-demand broadcasting system, comprising: reproducing means capable of reproducing information blocks included in a received stream in the order of reproduction. In a near-on-demand broadcast system including a server device and a terminal device that is communicably connected to the server device via an Internet network,
A main stream that is a main stream that is one of the streams that can be played back by the terminal device at a plurality of main transmission start times with a predetermined main transmission time interval, and that includes a plurality of information blocks having a playback order. A main transmission step for starting transmission of each information block from the server device in the order of reproduction;
When a transmission request signal is transmitted from the terminal device to the server device, the interpolation is one of the streams at a plurality of sub-transmission start times that are different from the main transmission start time and have predetermined sub-transmission time intervals. Interpolation stream that is a stream and is a part of information blocks included in the main stream and includes one or a plurality of information blocks with higher playback order, starts transmission of each information block from the server device in the playback order. Sub-transmission process to
A receiving step in which the terminal device receives a stream transmitted from the server device;
When one stream is received and another stream including an information block not included in the stream is received, information that is an information block not included in the one stream and included in the other stream A storage step in which the terminal device stores the block;
A near-on-demand broadcasting method comprising: a reproduction step in which a terminal device reproduces information blocks included in a received stream in the order of reproduction. It is connected to the terminal device via the Internet network so that it can communicate,
Transmitting means for transmitting a stream that can be played back by a terminal device, a main stream that is one of the streams and includes a plurality of information blocks having a playback order, and a predetermined main transmission time interval A main server that starts transmission of the stream so that each information block is transmitted in the order of reproduction for each of a plurality of main transmission start times with a gap,
An interpolation stream that is one of the streams, is a partial information block included in the main stream, stores an interpolation stream including one or a plurality of information blocks with higher playback order, and differs from the main transmission start time, And an interpolating server capable of starting transmission of the interpolated stream so that each information block is transmitted in the order of reproduction at each of a plurality of sub-transmission start times at predetermined sub-transmission time intervals; ,
A server apparatus comprising: transmission control means for causing an interpolation server to start transmission of an interpolation stream based on a transmission request signal transmitted from a terminal apparatus.   A program that causes a computer that is communicably connected to a terminal device via an Internet network to execute the function of the server device according to claim 3.

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