JPH08331547A - Video on demand service system for catv station - Google Patents

Abstract

PURPOSE: To realize the video on demand service in which a wait time from the reception of a request from a subscriber till a start time of a program is shorten even when number of reproducing the same program simultaneously is less in one CATV station with respect to the video on demand service system for the CATV station. CONSTITUTION: Plural CATV stations 1 are interconnected by a large capacity transmission line 8, each CATV station 1 is provided with a means sending one video image simultaneously as to each of programs and each CATV station 1 is provided with a broadcast schedule where a start time of reproducing video image of each program is set nearly at a prescribed interval among the stations. Upon the receipt of a viewing request designating a program from a subscriber of its own station, each CATV station 1 retrieves a broadcast schedule and sends a transmission request when a station having a least wait time is other station, and when each CATV station 1 retrieves a video signal via a transmission line 8 among the stations, the video signal is sent to a subscriber causing a request of its own station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for providing video on demand by a plurality of stations. In recent years, CATV (cable television) technology has adopted a system in which a program is broadcast in accordance with a broadcast schedule determined in advance for each channel. Therefore, a CATV subscriber sees the broadcast schedule, knows the broadcast time and channel of the program he / she wants to watch, and watches or records the broadcast according to the time. As a system to improve this, a video-on-demand service will be provided in which the subscriber will specify the program he / she wants to watch or the title of the video, and the center that provides the image will detect this and immediately send the corresponding image. Is required.

However, in order to provide a large number of subscribers as a video-on-demand service immediately,
Not only does the facility of the center become large in terms of hardware and software, but it is also necessary to increase the capacity of the transmission line connecting each subscriber and the center. It is required to provide services.

[0003]

2. Description of the Related Art In a conventional CATV, a program decided at a predetermined time is multiplexed and broadcast on a plurality of channels, and a subscriber of the CATV decides a desired program at a predetermined time. I was selecting and watching that channel. On the other hand, in recent years, as a service utilizing the bidirectionality of CATV, when a subscriber makes a request to a CATV station, a service of transmitting the program (video) as soon as possible from the requested point is provided. It became so.

As a conventional method for performing a video-on-demand service, there is a method described in, for example, Japanese Patent Application Laid-Open No. 5-41858, and an outline of the method is shown as an explanatory view of the conventional example in FIG. .

Referring to FIG. In the above, the CATV station 80 is provided with a plurality of video reproduction device groups 81 for repeatedly reproducing, for each of a plurality of types of videos (programs), a plurality of video signals whose reproduction times are shifted at regular intervals as independent video signals. , Switching means for selecting the output of the reproducing means for starting reproduction in the shortest waiting time of the video signals output from the video reproducing device group 81 in response to the viewing request designating the program from the subscriber terminal 85. The video signal assigned by 82 to the free channel of the transmission path and selected is transmitted from the transmitting means 83 via the assigned channel.

FIG. 6B. 8 playback devices (# 1 to # 8
The following shows an example of generating a video signal with the playback time shifted from (1), and after the first video starts playing for the same program for 2 hours in total, the second video starts playing back with a delay of 15 minutes. After that, the playback of the 8th video starts at the interval of 15 minutes, the playback of the 8th video starts 105 minutes after the start of the 1st playback, and 2 hours later, the playback of the next cycle of the 1st video starts. It

A conventional time-shift type service for broadcasting the same program on a plurality of channels at different times is called a near video on demand service.

[0008]

In the case of the conventional near video on demand service described above, the same program is played back 15 times.
In the case of a program of 2 hours shifted by minute intervals, 8 channels are used for transmission, and when the request is received from the subscriber, if the reproduction is started immediately before, it will be the maximum until the next reproduction is started. It is necessary to wait at least 10 minutes. In this case, the subscriber wastes waiting time, and the serviceability is not good.

Further, in the case of a long program, the number of channels cannot be increased. Therefore, for example, when a program of 3 hours is transmitted with 8 channels shifted in time, the time interval becomes 22 minutes or more. In this case, there is a problem that the user may have to wait until the start time or may forget the start time.

To shorten the time interval for starting reproduction, CA
While increasing the number of TV station playback devices and channels,
Although it is necessary to increase the capacity of the transmission line, neither can be adopted because the cost is huge.

According to the present invention, each of a plurality of CATV stations is capable of reducing the waiting time from the reception of a request from the subscriber to the start time of the program so that the number of times each program can be simultaneously reproduced is reduced. The purpose is to provide an on-demand provision method.

[0012]

FIG. 1 is a diagram for explaining the principle of the present invention. Is the principle configuration, B. FIG. 4 is an explanatory diagram of a broadcast schedule.

Referring to FIG. In the above, 1 is a CATV station (head end) installed in each area, and
··· Multiple CATV stations such as #n are provided.
2 is a control unit that controls subscriber terminals, manages broadcast schedules of other CATV stations and own station, and controls other parts, 2a is a table that stores broadcast schedules of own station and other CATV stations, and 3 is A video playback unit for performing playback by shifting for a fixed time determined for each program, 4 is a multiplex transmission / reception unit that multiplexes and sends a video to the transmission line on the subscriber side and receives a signal from the transmission line, and 5 is another CATV stations (# 2, # 3
.. # n) and a communication control unit for transmitting and receiving video signals and control signals, 6 is a transmission line on the subscriber side, 7 is a receiver of the subscriber, and 8 is for transmitting video signals and control signals between each CATV station. It is a large capacity transmission line.

According to the present invention, a plurality of CATV stations are connected to each other through a large-capacity transmission path, and each CATV station starts repetitive reproduction of each of a plurality of programs, or a reproduction start time is shifted to display a plurality of images. When playing back at the same time, the broadcast schedules of the stations with different start time positions are notified to each other, the broadcast schedules are held by each station, and when the request from the subscriber is received, the requested program is closest started. Select a station to play by time and the selected station is another CAT
In the case of the V station, the transmission is requested to the corresponding other CATV station, the transmitted video is received, and transmitted to the requesting subscriber.

[0015]

The control unit 2 of each CATV station controls the communication control unit 5 via the large-capacity transmission line 8 to broadcast a broadcast schedule from another CATV station to start reproduction by shifting the time for each program. Upon reception, the control unit 2 stores it in the table 2a. Also, the broadcast schedule of the own CATV station 1 (# 1) is set in the table 2a and is transmitted from the communication control unit 5 to other stations. In this case, each CAT
There is a case where the reproduction time of each program of the V station is shifted (when a plurality of programs are reproduced in parallel) and a case where only one is reproduced at each station. In both cases, it is decided that the time positions of the reproduction start are mutually dispersed, It is easy to determine the broadcast schedule at each station and notify from that station to other stations without relying on comprehensive notification.

Referring to FIG. Each CA for one program
An example of a broadcasting schedule of TV stations is shown. In this example, four CATV stations # 1 to # 4 are connected to each other by a large-capacity transmission line 8, and each station plays a program whose reproduction time is T and a fixed time. The reproduction of the same program is started every T / n (n ≧ 1). When n = 1, only one video is played back from one station at the same time, and when n ≧ 2, a plurality of videos are played back simultaneously from one station by time shifting.

In each of the CATV stations # 1 to # 4, the reproduction start time positions are dispersed in advance, and the B.B. Example, # 1, # 2, #
The time position of each reproduction start of each station of 3 and # 4 is T / 4 (n =
Example 4) The # 2 CATV stations are sequentially shifted by time,
Scheduled to be at a time position delayed by T / 4 hours from the time position at which the # 1 CATV station was restarted, # 3
CATV station is scheduled to be delayed by 2T / 4 hours from the reproduction start time position of the # 1 CATV station, and the # 4 CATV station is 3T / 4 from the reproduction start time position of the # 1 CATV station. It is scheduled to be delayed by the time.

When a program is requested from the subscriber's receiver 7,
The signal is sent to the control unit 2 via the multiplex transmission / reception unit 4 of the CATV station 1. The control unit 2 identifies the CATV station having the closest reproduction start time of the requested program by the table 2a. In the case of another station, the communication control unit 5 sends the program and the corresponding channel (reproduction start time) to the other station. Specify and request transmission. When a requested video is received from another station via the large-capacity transmission line 8, it is input to the video reproduction unit 3 via the communication control unit 5.

When the reproduction start time of the local station is the closest, the control unit 2 selects the video signal from a plurality of videos to be reproduced with the time generated from the video reproduction unit 3 being shifted, and the other video signal is selected in response to a request. In the case of an image sent from a station, the multiplex transmission / reception unit 4 is controlled so as to select the video signal. The selected video is multiplexed with other video signals and transmitted to the transmission line 6 to which the receiver 7 of the requesting subscriber is connected.

The broadcast schedule is transmitted not through the large-capacity transmission line 8 but through an existing network such as a public telephone network, and only the video signal is transmitted through the large-capacity transmission line 8. It can be configured to transmit. Also, instead of sending and receiving the broadcast schedule at each station, one station creates a schedule for each station and notifies the other stations,
Each station may control the reproduction start time of its own station according to the schedule.

The requesting subscriber can receive the reproduced video of the requested program in a shorter waiting time than in the case where the CATV 1 provides it alone. In addition, each CATV station does not increase the number of new video playback devices, only by providing a communication device using a large-capacity transmission line (optical fiber or the like) that connects to other stations, and the transmission line on the subscriber side is not increased. The serviceability of video on demand can be improved without adding a new channel to.

[0022]

FIG. 2 shows an example of the system configuration of a plurality of CATV stations according to the present invention. In FIG. 2, 1 is C
It represents an ATV station, and in this example, it is composed of five stations: A station, B station, C station, D station, and X station, and each station is configured with a receiver of each video signal and a terminal for transmitting and receiving a control signal. A transmission line 6 such as a coaxial cable for connecting to a subscriber terminal device (corresponding to the receiver 7 in FIG. 1) is connected. In the case of the X station, the transmission lines 6a to 6c are laid for each route and a large number of subscriber terminal devices are connected to each, but in the example of FIG. 2, one is added to each of the transmission lines 6a to 6c. Only the person terminal devices A to C are shown. The large-capacity transmission line 8 interconnecting each station is a large-capacity network (wideband ISDN) using optical fibers.
Or a dedicated optical fiber network). Reference numeral 9 denotes a public network (telephone network or data network), which is not used when transmitting / receiving the broadcast schedule of each station via the large-capacity transmission line 8, but it may be transmitted / received via the public network 9 depending on conditions. You can Each video signal is converted into a digital signal and transmitted through the transmission lines 6 and 8.

FIG. 3 is a block diagram of an embodiment of the CATV station, showing the configuration of each CATV station 1 of FIG. In FIG. 3, 10 is a central control unit that controls each unit, 11 is a subscriber terminal control unit that receives a request from a subscriber terminal device and sends a control signal to the subscriber terminal device, and 12 is each CA.
A schedule management unit for managing the TV station schedule 12a, 13 is a character generation unit for generating characters of information such as broadcast time selected by the schedule, and 14 is a large capacity with another CATV station. A communication control unit 15 for transmitting and receiving video and control information via the transmission path 8 of
Is a video transmission that reproduces the videos of many programs of its own station according to a schedule and sends the reproduction images requested by the subscriber's own station transmission line and other stations to the large-capacity transmission line 8 via the communication control unit 14. The unit 16 restores the video (each including a plurality of channels) received from another station (decompresses the compression coding to restore it), and the restore unit 17 restores the restored video to NT.
Modulator that modulates to SC system and converts frequency, 1
Reference numeral 8 denotes a head end that multiplexes a plurality of video signals together with a control signal to a transmission line 6 to which each subscriber terminal device is connected (actually, a plurality of transmission lines 6 are connected) and transmits the received control signal. is there. It should be noted that reference numerals 6 and 8 are the same as those in FIG. 2 and represent a transmission line and a large capacity transmission line, respectively.

FIG. 4 shows an example of a broadcast schedule management method and schedule. Indicates the management method, and B. Shows an example of a broadcast schedule. In this example, the five CATV stations (stations A to D, X station) shown in FIG. 2 are connected by a large-capacity transmission line. A. of FIG. As shown in, the station X creates a broadcast schedule of programs to be broadcast in common to each station including its own station. An example of the created schedule is shown in FIG. Is shown in. This schedule is made up of items, program names (movies with the same title), broadcast time at each station, start time, end time, and providing station name. In addition, B. The example of is when each station broadcasts the movie of this title only once, and the 120-minute movie is shifted by 24 minutes at each station (this time becomes shorter as the number of stations increases), and then the broadcast is started. There is. In this case, it is not necessary for each station to start playback in sequence by shifting the time, and the number of playback devices can be reduced, and the number of channels can be reduced.

However, it is obvious that a plurality of reproductions can be performed at each station by shifting the time. For example, in the case where each station starts reproduction (broadcast) by shifting the time every 30 minutes, the station X is 8:00, 8:30, 9: 0
It became 0, 9:30, and station A was 8:06, 8:36,
9:06, 9:36, station B: 8:12, 8:42 ...
In this way, the reproduction start interval between stations is 6 minutes.

B. of FIG. Broadcast schedule like X
When created by the station, A. As shown in, the broadcast schedule is transmitted from the X station to the adjacent A station. In this case,
In the configuration shown in FIG. 2, the schedule management unit 12 transmits the data to the A station via the communication control unit 14 and the large-capacity transmission line 8 and stores it in the table 12a of the schedule management unit 12 of the A station. It is transmitted to station B, and then to station D in the same manner, and the same broadcast schedule is used for each station in Table 1.
2a. The broadcasting schedule can be transmitted from the communication control unit 14 to the other stations A to D via the public network (telephone network, data network).

FIG. 5 shows an example of an operation sequence for providing an image across a plurality of stations. And B. 2 are shown below, and it is assumed that a plurality of stations are arranged as shown in FIG.
A. From the subscriber (subscriber terminal device) P of station X at 8:03
When a viewing request is made by designating a program at 0 minutes (a in FIG. 5A), the subscriber terminal control unit (11 in FIG. 3) of the X station receives this and notifies the central control unit 10. Central control unit 10
In response to this request, instructs the schedule management unit 12 to detect the station having the closest broadcast start time, and the schedule management unit 12 searches the table 12a (A.
B), station 8:48 is detected. The search result is converted into characters by the character generator 13, modulated by the modulator 17, and notified to the transmission path of the subscriber P from the head end 18 (c in A. of FIG. 5). At this time, the central control unit 10 also notifies the subscriber P of the channel to be viewed.

The central control unit 10 sends a video transmission request to the station B having the detected closest broadcast start time (d in A. of FIG. 5). Upon receipt of this request, station B starts playback of the requested program at 8:48 and sends it to the subscribers of its own station and also transmits to the requested station X via the large-capacity transmission line 8. Yes (same e). In this case, station B sends out from the video sending unit 15 of FIG. 3 to the large capacity transmission line 8 via the communication control unit 14.

Upon receiving this, the X station receives it at the communication control section (14 in FIG. 3), restores it at the restoration section 16, further modulates it at the modulation section 17, and makes a request via the headend 18. The person P transmits to the transmission path 6 to which the person P is connected. In this case, in the X station, when the communication control unit 14 of FIG. 3 receives the video from the large capacity transmission line 8, the decompression unit 16 decompresses the compressed video, the modulation unit 17 modulates the TV image, and the head end 18 The channel is converted into the channel designated by and is transmitted to the transmission line 6 to which the subscriber P is connected.

Next, referring to FIG. In the example, when the subscriber P of the X station makes a viewing request (a in B. of FIG. 5), the X station searches the broadcast schedule table and selects the C station as the station with the shortest waiting time. (Same as b), Waiting time and Channel to be viewed are notified (Same as c). The waiting time is obtained by calculating the difference between the current time and the broadcast time of station C. On the other hand, from the central control unit 10 (FIG. 3) of the X station to C
A video transmission request including the program name and start time is transmitted to the station (d in B. of FIG. 5). The adjacent D station grasps (identifies) this information (at the same e) and requests the C station to transmit the image (at the same f). After that, when the subscriber Q of the D station requests the transmission of the same program as the subscriber P (the same g), the central control unit 10 (FIG. 3) of the D station, the C station with the shortest waiting time. Is selected (the same h), and the waiting time is notified to the subscriber Q (the same i).

After that, when the broadcast of the program (the program requested to be transmitted) is started in the C station according to the schedule, the C station transmits the video signal to the D station (at j). When the D station receives this signal, it transmits the signal to the X station (at the same k), and also controls to branch to the subscriber Q of its own station and transmit (at the same l). In the X station, when the video signal requested to be transmitted is sent from the D station, the A. The same process is performed to transmit to the subscriber P of the own station through the designated channel (same m).

[0032]

According to the present invention, common CATV stations can broadcast common video software at different times to quickly provide a video in response to a request from a subscriber.

Further, as the number of stations connected by the communication means increases, the waiting time of the subscriber can be shortened, and the scale of the equipment can be increased as compared with the case where a single CATV station provides the same level of service. It can be made smaller, and complaints about waiting time from subscribers can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing an example of a system configuration of a plurality of CATV stations according to the present invention.

FIG. 3 is a configuration diagram of an embodiment of a CATV station.

FIG. 4 is a diagram showing an example of a broadcast schedule management method and schedule.

FIG. 5 is a diagram showing an example of an operation sequence of video provision over a plurality of stations.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 CATV station 2 control unit 2a table for storing broadcast schedule 3 video reproduction unit 4 multiplex transmission / reception unit 5 communication control unit 6 subscriber side transmission line 7 subscriber receiver 8 large capacity transmission line

Claims (5)

[Claims] 1. A means for connecting a plurality of CATV stations, each of which sends video to a plurality of subscribers, by a large capacity transmission line, and each CATV station includes means for sending one video at a time for each program. , Each CATV station stores a broadcast schedule in which the start time for reproducing the video of each program is set at a substantially constant interval between stations, and each CATV station
When the TV station receives a viewing request designating a program from a subscriber of its own station, it searches the broadcast schedule and selects its own station or another station with the least waiting time, and the selected station is the other station. In that case, when a transmission request is transmitted to another station and a video signal is transmitted from the other station via the transmission path between the stations, the video signal is transmitted to the subscriber who has issued the request of the own station. A video-on-demand provision system for CATV stations characterized by: 2. The CATV stations according to claim 1,
Each CATV station is provided with a means for sequentially reproducing a plurality of images by shifting a certain time for each program and simultaneously transmitting a plurality of images, and each CATV station has a start time for reproducing a plurality of images of each program in each station. A video-on-demand providing system for CATV stations, in which broadcast schedules set at substantially constant intervals are stored. 3. The CATV station according to claim 1 or 2, which has received the viewing request designating the program from the subscriber, identifies the broadcast time of the station with the least waiting time,
A video-on-demand providing system for a CATV station, characterized in that the subscriber who has made the viewing request is notified of a broadcast start time or a waiting time. 4. The plurality of CATV stations according to claim 1 or 2, wherein the plurality of CATV stations are sequentially connected in a ring shape by the large-capacity transmission line, and the broadcast schedule is transmitted via the transmission line connecting the stations. CAT which is sequentially transmitted from one station to the next station and stored in each station in sequence
Video-on-demand system for V stations. 5. The video-on-demand for a CATV station according to claim 1 or 2, wherein the broadcast schedule is transmitted from a station that creates the schedule to each of the other CATVs via a public network. Provision method.