JPH07162623A - Distribution service system for image - Google Patents

Abstract

PURPOSE:To reduce the congestion of circuits and to improve the working efficiency of circuits by transmitting the distribution data in a splitted form and then reforming the data at a terminal. CONSTITUTION:A CATV center 1 continuously monitors the idle state of a circuit until the starting time of distribution of data and distribute partly the image information to the circuit when it becomes idle at night or in other time bands. A subscriber terminal 3 records the received signals in an image file 11. When the terminal 3 receives data, the terminal 3 returns the received signals to the original image information. A received signal processing circuit 8 sends the image information to a synchronizing reproduction control circuit 12. The circuit 12 reads the complement data out of the file 11 via an interface circuit 10 and delays these data by are produced signal processing circuit 13. The reproduced data are outputted from the circuit 13 and then supplied to a multiplexer 14 together with the data received from the circuit 8. These data are reformed into a piece of image information data based on the control signal received from the circuit 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image information distribution service system for distributing an image from an image information database to a subscriber's terminal in response to a subscriber's request.

[0002]

2. Description of the Related Art As a service for distributing image information to subscribers from a center station that stores image information, for example, cable television (hereinafter, CATV: CAble TeleVision)
It has been known. Regarding the current CATV technology, Vol. 4 of the Institute of Television Engineers of Japan "Image Information Engineering and Broadcasting Technology"
7 No. 8 “Technical Trends of Cable Television” August 1993
Monthly issue See pages 1048 to 1087 for details. According to this document, using the current CATV service, it is possible to receive a multi-channel service of 25 to 58 channels only by pulling one coaxial cable into a subscriber's house. Among these services, there are retransmission of terrestrial broadcasting and satellite broadcasting, transmission outside the area, and voluntary broadcasting distributed by the program provider itself. However, all of these are unilaterally transmitted according to a program determined by the CATV station side, as in general television broadcasting.

Therefore, in order for the CATV business to have an advantage over other broadcasting businesses, it is required to further increase the number of channels and realize various services. Assumed services are time shift service (same program is shifted by about 10 minutes with start time distributed on multiple channels), TV shopping (select items on TV screen and place order), PPV (Pay Per View). : Pay the fee according to the program watched), video on demand (deliver the program desired by the subscriber at the desired time), etc.

These services require more lines, such as using a plurality of channels for one program, or requiring two lines from a CATV station to a subscriber and a subscriber to a station.

To implement these services, 1
It is necessary to develop a system having a line capacity exceeding 00 channels. For this reason, it has been considered to replace the conventional coaxial cable with a wide band such as an optical fiber or to compress the band of transmission data by using a high efficiency coding technique.

However, it is known that when the compression rate by the high efficiency coding is increased, the image quality is sharply deteriorated, and the compression rate is inevitably lowered in a program such as a movie where the image quality is important. Considering the distribution of such programs as video-on-demand, even if an optical fiber is used for the transmission line, it is possible that the demand may be concentrated and the line may be saturated at some time. It's easy to imagine because the patterns are similar.

One method of avoiding such a line saturation is to move a part of the line users at the time of congestion to a time zone such as nighttime when the line is idle. So far, a method has been proposed in which, assuming a service that does not require real-timeness, program distribution is performed during a time zone such as night when the transmission channel is relatively free. For example,
There is a "moving image information reservation providing system" described in JP-A-62-183242 and a "video distribution device" described in JP-A-3-120985. According to these inventions, means for recording a program is provided in the terminal of the subscriber side, the program distributed at night is recorded in the means for recording, and the program is reproduced from the recording means at the time desired by the subscriber. It is intended to be viewed.

[0008]

In the invention described in the above publication, since the program is recorded in the recording means connected to the subscriber terminal, it is possible to perform high-efficiency encoding up to the data transfer rate which can be realized by the recording means. Needs to be compressed. However, there is a problem in that currently available recording means cannot obtain a sufficient storage capacity or transfer rate, so that only a program having a high compression rate and poor image quality can be recorded.

Further, in the invention described in the publication, a complete copy of the program is created in the recording means connected to the subscriber terminal. Care must be taken not to infringe copyright when creating a copy of such image information. Since this copy is made by the center side, not by the subscriber, it is considered necessary for the center to protect the copyright. That is, it is necessary to take measures so that the subscriber cannot freely copy or edit the video information stored in the storage means. Since the cost incurred for this measure is usually reflected in the CATV usage fee, there arises a problem that the fee becomes high.

An object of the present invention is to reduce line congestion and improve usage efficiency.

[0011]

The image information distribution service system of the present invention is an image information distribution service system for providing image information accumulated in a center to a terminal at a designated time in response to a request from the terminal. The terminal is provided with a means for storing image information, the center distributes part of the image information data by the designated time and stores it in the means for storing, and at the designated time, delivers the remaining image information data. Then, the terminal synchronously reads the received data that complements the remaining data from the storage unit, and combines the remaining data and the data read from the storage unit in the terminal to display image information. It will be reconstructed.

[0012]

When the image information distribution request is received from the terminal, the center first checks the specified distribution time. Then, when the delivery is requested immediately, the normal video-on-demand process is immediately executed. If there is a time until the designated time, a part of the image information is distributed at any time by anticipating the time when the line utilization rate is low, and recorded in the storage means of the terminal. The image information distributed at this time is, for example, one of high-efficiency-encoded data divided into two, one of screen data divided into two, or time-series data divided in time. The data of the former one may be used. Of course, the data to be distributed at this time is not the image information that is displayed on the terminal in real time, so it may be distributed at a slower speed than usual, or the data may be distributed in small portions. At the designated time, the center starts distributing the remaining image information data. When this is received by the terminal, it is read from the means for storing the data necessary for complementing the received data and reconstructing the image information, and reconstructing the image information together with the received data.

When the remaining image data is distributed, it is necessary to transmit it in real time. However, since part of the image information has already been distributed, the required line capacity is smaller than that of normal video-on-demand. Complete. Therefore, even when the designated time is busy, the video-on-demand can be used with a small bandwidth. Also, since part of the image information is distributed when the line utilization rate is low, the line utilization efficiency can be improved.

Further, since the storage means of the terminal and the transmission line are used together, the line capacity or storage capacity and the transfer speed can be apparently increased as compared with the case where the transmission line or the storage means is used alone. Therefore, it is possible to reduce the compression rate of high-efficiency coding, and it is possible to distribute a high-quality program.

Further, since only a part of the image information distributed in advance cannot be used as the image information, it is meaningless for the subscriber to copy or edit the image information. Therefore, even if a means for storing in the terminal is provided, it is not necessary to add a special device for copyright protection, so that it does not lead to an increase in the usage fee.

[0016]

1 is a schematic diagram of a CATV service according to an embodiment of the present invention. In FIG. 1, 1 is a CATV center, 2 is a CATV hub, 3 is a subscriber terminal, 4 is a command input device, 5 is a monitor, 6 is a transmission signal processing circuit, 7 is a transmission / reception interface circuit, 8 is a reception signal processing circuit, 9 is a recording signal processing circuit, 10 is a recording / reproducing interface circuit, 11 is an image file, 12 is a synchronous reproducing control circuit, 1
Reference numeral 3 is a reproduced signal processing circuit, 14 is a multiplexer, 15 is a decoded signal processing circuit, and 16 is a transmission line. Below,
An embodiment of the present invention will be described with reference to FIG.

First, the CATV center 1 and the subscriber terminal 3 are connected by the transmission line 16 via the CATV hub 2. The transmission line 16 is composed of a plurality of channels. CA
There are generally a plurality of subscriber terminals 3 connected to the TV hub 2, and the CATV hub 2 uses all channels for the subscriber terminals 3.
The system price is reduced by distributing only the necessary channels instead of connecting to the. Also, CA
The connection method between the TV center 1 and the subscriber terminal 3 is not limited to this example, and there are many modes. An example thereof is described in detail in the above-mentioned document “Technical Trend of Cable Television”. The connection method between the CATV center 1 and the subscriber terminal 3 of the present invention may take any form.

Next, consider the case of implementing video on demand. The subscriber requests distribution of image information from the command input device 4 connected to the subscriber terminal 3. This request signal is sent to the CATV center 1 via the transmission signal processing circuit 6, the transmission / reception interface circuit 7, and the CATV hub 2. If this request signal requests the start of distribution immediately, the CATV center 1 immediately checks the usage status of the line. At this time, if there is not enough free line to deliver the requested image information, the CATV hub 2
A request rejection signal is sent to the subscriber terminal 3 via the.
This request rejection signal is input to the reception signal processing circuit 8 via the transmission / reception interface circuit 7. Since the signal transmitted from the CATV center 1 has been subjected to signal processing so as to be efficiently transmitted through the transmission line 16, it is returned to the original signal by the reception signal processing circuit 8. This signal is sent to multiplexer 1
4, is displayed on the monitor 5 through the decoded signal processing circuit 15,
The subscriber will be notified that the request has been denied.

If the line has sufficient space,
The CATV center 1 starts distribution of image information compressed by high efficiency coding to the subscriber terminal 3 via the CATV hub 2. This image information is input to the multiplexer 14 via the transmission / reception interface circuit 7 and the reception signal processing circuit 8. In this case, the multiplexer 14 is always set to output the signal from the received signal processing circuit 8.
The output signal of the multiplexer 14 is the decoded signal processing circuit 15
And the signal compressed by the high-efficiency coding is decoded. This decoded signal is displayed on the monitor 5, and the subscriber can view the requested image information.

Next, let us consider a case where the subscriber specifies the image information distribution start time. The CATV center 1 monitors the availability of the line until the delivery start time, and delivers part of the image information when the line is idle such as at night. Upon receiving this, the subscriber terminal 3 sends the reception signal to the transmission / reception interface circuit 7 and the reception signal processing circuit 8, and restores the signal converted into the transmission signal. Next, this signal is applied to the recording signal processing circuit 9
Then, signal processing for recording the image file 11 is performed, and the signal is recorded in the image file 11 via the recording / reproducing interface circuit 10. In this way, a part of the image information requested by the subscriber is recorded in the image file 11 of the subscriber terminal 3 by the designated delivery start time. During this time, the image information does not need to be delivered in real time, so the transfer rate may be lower than usual, or if the line becomes congested midway, it may be interrupted and wait for the line to become free. . At the distribution start time, the CATV center 1 starts distribution of the remaining image information data. However, this data must be delivered in real time.

Upon receiving the data, the subscriber terminal 3 returns the received signal to the original image information via the transmission / reception interface circuit 7 and the received signal processing circuit 8. The reception signal processing circuit 8 sends the image information to the synchronous reproduction control circuit 12, and the synchronous reproduction control circuit 12 sends a control signal to the recording / reproduction interface circuit 10 so as to read the data that complements the transmitted image information from the image file 11. . In response to this, the recording / reproducing interface circuit 10 reads the data from the image file 11, and the reproduced data is sent to the reproducing signal processing circuit 13 via the recording / reproducing interface circuit 10. Since the reproduction data has been converted to match the characteristics of the image file 11, the reproduction signal processing circuit 13 restores the reproduction data. The reproduction data output from the reproduction signal processing circuit 13 and the reception data output from the reception signal processing circuit 8 are both input to the multiplexer 14 and combined into one image information data according to the control signal output from the synchronous reproduction control circuit 12. This is sent to the decoded signal processing circuit 15, decoded from the high-efficiency coded data, and displayed on the monitor 5. Through these processes, the subscriber can view the image information.

According to this embodiment, since image information is distributed during a time period when the conventional line utilization efficiency is low, the line utilization efficiency can be improved. Moreover, since the transmission line 16 and the image file 11 are used together when viewing image information, the capacity,
The transfer rate can be large. With this effect, the compression rate of the image information by the high efficiency encoding can be reduced, and the image information can be distributed without significantly degrading the image quality. This is particularly advantageous for delivering high-definition images with excellent image quality. Further, the image information recorded in the image file 11 is meaningless unless it is combined with the remaining image information transmitted from the CATV center 1. Therefore, it does not make sense for the subscriber to take out the image information recorded in the image file 11 and make a copy or edit it. Therefore, the copyright protection is implemented even if a new device is not provided. it can.

[0023]

According to the present invention, congestion of the transmission line can be alleviated and the use efficiency can be improved. Further, since the apparent capacity and the transfer speed can be improved, the image information can be distributed without significantly degrading the image quality. Furthermore, copyright protection can be implemented without preparing a special device.

[Brief description of drawings]

FIG. 1 is a block diagram of a CATV service system according to an embodiment of the present invention.

[Explanation of symbols]

1 ... CATV center, 2 ... CATV hub, 3 ... subscriber terminal, 4 ... command input device, 5 ... monitor, 6 ... transmission signal processing circuit, 7 ... transmission / reception interface circuit, 8 ... reception signal processing circuit, 9 ... recording signal Processing circuit, 10 ... Recording / playback interface circuit, 11 ... Image file, 12 ... Synchronous playback control circuit, 13 ... Playback signal processing circuit, 14 ... Multiplexer, 15 ... Decoded signal processing circuit, 16 ... Transmission line.

Claims (1)

[Claims] 1. An image information distribution service system for providing image information accumulated in a center to a terminal at a designated time in response to a request from the terminal, the terminal being provided with means for storing the image information, Distributes a part of the image information data by the designated time and stores it in the storing means, and when the designated time comes, starts distribution of the remaining image information data, and the terminal receives the remaining data. An image characterized by reconstructing the image information by synchronously reading out data that complements the data from the storage means, and combining the remaining data and the data read out from the storage means in the terminal. Information distribution service method.