KR100310778B1 - Method for providing special playback service in video on demand service - Google Patents

Abstract

The present invention relates to a method for providing a special playback service for video on demand, which enables a fast forward or fast backward playback service according to a client's request in real time when the video on demand is served in MPEG stream form from a server to a client. To this end, according to the present invention, each time a new program is registered for the on-demand service in the server, N number N times fast forward and N number N times fast backward playback MPEG corresponding to the registered program in consideration of the load state of the server is considered. One of the MPEG video streams for fast forward and fast backward playback, when the video streams are created and stored in an auxiliary storage medium, and have a special playback service request for fast forward or fast backward playback from a client currently being delivered. To the client By greatly reducing the load on the server caused by the fast forward or fast reverse playback service according to the client's request, the service can provide a fast forward or fast backward playback service to the client in real time without deterioration of image quality. It can be.

Description

How to provide special playback services for video on demand {METHOD FOR PROVIDING SPECIAL PLAYBACK SERVICE IN VIDEO ON DEMAND SERVICE}

The present invention relates to a method of providing a video on demand (VOD) service to a client in a remote server. More particularly, the present invention provides a VOD service of noninterlace video from a server to a digital television (DTV). The present invention relates to a method for providing a special playback service of video on demand suitable for providing a fast forward or fast backward playback service in response to a user request.

In recent years, with the rapid development of the semiconductor and information and communication industries, the construction of the high-speed information and communication infrastructure, which started from the super highway concept of information, is rapidly spreading, and the information is provided in an interactive and active manner rather than simply receiving the information manually. Increasingly, the desire of users to obtain high-end digital cameras (I-CATV), an advanced form of cable television (CATV), is now commercially available as a way to meet these needs. Commercial products of interactive digital television are appearing one after another.

On the other hand, the use of digital interactive cable television service technology instead of analogue technology enables on-demand video (TV, etc.) information to be instantly delivered at the desired time. VOD) service is available. In order to realize such an on-demand video service, an information provider consisting of a large capacity server capable of storing and transmitting information, a service provider such as a television broadcasting station, and information requested from a service provider through a network at a high speed can be obtained. There is a need for a delivery system provider and a television user to use (or use) service information provided from a delivery system provider for simultaneous delivery to multiple television users.

As described above, services that can be realized on demand video include, for example, Movies On Demand (MOD), News On Demand (NOD), Remote Shopping, Telemedicine Diagnosis, Gaming, Home Banking, Video Conferencing, Agreement Services for Commerce, Internet access service, etc. can be mentioned.

On the other hand, in order to implement the VOD service, the client requests a delivery service such as a program, for example, a movie program or a news program, to a remote server according to a user's operation, and the server responds to the request from the client. Fetches a bit stream of video and audio data, i.e. video, audio, and text, for the requested program from the storage medium and delivers it to the client who requested the service. At this time, when the client is a digital television (DTV), a set-top box, or the like that processes video and audio signals of the MPEG stream, the service information provided from the server to the client according to the service request of the client becomes the MPEG stream.

Therefore, the program data (or MPEG stream) provided from the server to the client of the user in accordance with the user service request is restored to the original signal before encoding through the MPEG decoder in the client, and the restored video signal is displayed on the monitor.

On the other hand, when providing the information service (i.e., providing a playback service) of the MPEG stream from the server to the client according to the client's request, a special playback service such as in a conventional analog VCR, for example, backward playback (i.e., movement) It provides special playback services such as reverse backward normal speed), fast forward playback, fast reverse playback, slow forward playback, and slow backward playback. Herein, the present invention relates to a fast forward or fast backward playback service provided when an on-demand video program is a video signal in noninterlace mode.

Therefore, when the server requests a special playback service, for example, a fast forward or fast backward playback service, on the client side, the server suspends the normal playback service of the program currently being serviced, and then starts a high-speed service for the service request program from the point of interruption. An MPEG stream for forward or fast backward playback is generated and sent to the client.

However, the conventional method described above has a problem that it is difficult to perform real-time processing because it has to go through a complicated process such as decoding and rearranging the MPEG video stream to generate an MPEG video stream for fast forward or fast backward playback. This also puts a lot of load on the server, making it a huge constraint on providing real-time, on-demand video services to other clients.

On the other hand, in order to minimize the above-mentioned problems caused when providing a fast forward or fast backward playback service in response to a client's request, the deduced fast forward generated by extracting and decoding only the I picture and rearranging encoding them. Alternatively, a method of serving an MPEG video stream for fast backward playback to a corresponding client has been proposed.

However, this method can reduce the real-time processing and load on the server to some extent, but the fast forward or fast reverse image is displayed because the continuity of the fast forward or fast reverse playback image is markedly reduced on the client side. I have another problem. That is, I pictures exist in a normal 15 picture in a non-interlaced mode, and when a picture is composed and displayed only by the I pictures, a smooth picture is displayed in which movement is minutely broken.

The present invention is to solve the above problems of the prior art, it is possible to provide a fast forward or fast backward playback service in real time according to the client's request when the video on demand server in the forward scan mode in the form of MPEG stream from the server to the client The purpose is to provide a method for providing a special playback service of video on demand.

In order to achieve the above object, the present invention provides a client server system having a server for fetching program data in an MPEG stream including a video stream in forward scanning mode from a storage medium to a client requesting a service in response to a delivery service request. A method of providing a special playback service in a mobile station, comprising: N pictures of encoded video streams in the encoded MPEG stream of the registered program are n: 1 each time a new program is registered in the storage medium. Generating a stream and storing the streams in an auxiliary storage medium, wherein n is a positive integer except 1; The N pictures are encoded in the encoded MPEG stream of the registered program in the reverse order of n: 1 to generate N N times fast backward playback MPEG video streams, and the generated N N times fast backward playback MPEG video streams. A second process of storing n in the auxiliary storage medium, wherein n is a positive integer except 1; A third step of fetching an MPEG stream of a requested program from the storage medium and transmitting it to the service request client when a delivery service is requested from any client; A fourth step of checking whether a fast forward or fast reverse playback service request is received from the service request client while performing the delivery service; Upon receipt of the fast forward or fast reverse playback service request, suspend the delivery service and select one of the plurality of N times fast forward or N times fast backward playback MPEG video streams based on the requested double speed; A fifth step of extracting the selected N-times fast forward or N-times fast backward playback MPEG video stream at a position corresponding to an interruption of a delivery service as a service start point and transmitting the same to the service request client; A sixth process of performing the fifth process until there is a stop request for the fast forward or fast reverse playback service from the client; And a seventh process of stopping the fast forward or fast reverse playback service and resuming the delivery service based on a position corresponding to the interruption time point when the fast forward or fast backward playback service interruption request is made. Provide a special playback service providing method.

1 is a schematic block diagram of a client server system suitable for providing a special playback service in video on demand using digital television according to the present invention;

2 is a flowchart illustrating a process of providing a fast forward or fast backward playback service according to a client's request when servicing video on demand from a server to a digital television (DTV) according to a preferred embodiment of the present invention;

3 is a diagram illustrating an example of converting a normal picture stream into a picture stream for fast forward playback in order to provide a fast forward playback service according to the present invention;

4 is a diagram illustrating an example of converting a normal picture stream into a picture stream for fast backward playback to provide a fast backward playback service according to the present invention.

<Description of the code | symbol about the principal part of drawing>

100: server 102: control block

104: main storage medium 106: memory block

108: buffer memory 110: decoding block

112: temporary memory 114: encoding block

116: secondary storage medium 200: DTV (client)

202: control block 204: MPEG decoding block

206: Video encoding block 208: Menu occurrence block

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of a client server system suitable for providing a special playback service in video on demand using digital television in accordance with the present invention, wherein the server 100 and the client, such as a digital television (DTV) 200, are shown. ).

As shown in FIG. 1, the server 100 includes a control block 102, a main storage medium 104, a memory block 106, a buffer memory 108, a decoding block 110, a temporary memory 112, The encoding block 114 and the secondary storage medium 116, and the client, the DTV 200, controls the control block 202, the MPEG decoding block 204, the video encoding block 206 and the menu generation block 208. Include.

Referring to FIG. 1, the control block 102 includes, for example, a microprocessor to perform overall operation control of a server. An on-demand video service (eg, When the request signal is received, the MPEG stream of the program requesting the service is transmitted to the client through the interface block.

Here, the main storage medium 104, for example, N disks each containing a plurality of programs (e.g., movie programs, etc.) compression-coded into an MPEG stream in a noninterlaced mode in the form of a tray It is a storage medium to be loaded, and each program data stored therein is prepared for an on-demand video service.

In addition, the memory block 106 includes program guide information for programs capable of video-on-demand (ie, programs registered and stored in the main storage medium 104), for example, program title, supervision, starring, and total running time. The program guide information such as, an outline, etc. is stored, and the on-demand video menu data is fetched at the request of the menu service from the client and transmitted to the client side requesting the menu service through the control block 102. In addition, the buffer memory 108 stores control information necessary for the execution of the on-demand video service, that is, program storage position information, and storage position information of programs for fast forward and fast reverse playback generated for the performance of the present invention. Such information storage and deletion in the memory block 106 and the buffer memory 108 is performed by the control block 102.

On the other hand, the decoding block 110 is an MPEG video stream from the control block 102 to generate an MPEG video stream for fast forward or fast backward playback in forward scanning mode for providing a fast forward or fast backward playback service according to the present invention. When provided, these MPEG video streams are restored to the original signal before encoding and provided to the control block 102, which is temporarily stored in the temporary memory 112.

Next, the control block 102 fetches the reconstructed video stream stored in the temporary memory 112 to perform n: 1 picture forward deduction for generation of the MPEG video stream for fast forward playback, e.g., 2x fast forward. In the case of inferiority, as shown in FIG. 3, the picture is forwarded in the order of picture 1, picture 3, picture 5,-----n-1 in order from pictures 1 to n. By generating a video stream for double-speed forward playback, a video stream for high-speed forward playback, such as 4x high speed and 8x high speed, is generated, and the video streams for high speed forward playback are sequentially encoded according to the speed Provided to block 114.

Accordingly, the encoding block 114 sequentially encodes each reconstructed fast forward video stream provided from the control block 102 to the MPEG video stream again using a well-known MPEG encoding technique, and then the control block 102. Pass each to For example, the 2x fast forward video stream, the 4x fast forward video stream, and the 8x fast forward video stream are sequentially coded according to the input order and delivered to the control block 102.

In addition, in the control block 102, when the generation of the MPEG video stream for the fast forward playback is finished, n: 1 picture backward truncation for generation of the MPEG video stream for the fast backward playback is performed, for example, 2 In case of double-speed backward deferring, as shown in FIG. 4, n pictures, n-2 pictures, n-4 pictures,-----2 pictures in the reverse order of pictures 1 to n. A backward stream is decremented to generate a video stream for 2x fast backward playback, thereby generating a video stream for fast backward playback such as 4x high speed and 8x high speed. It is provided to the encoding block 114 sequentially in order.

Accordingly, the encoding block 114 sequentially encodes each reconstructed high-speed backward video streams provided from the above-described control block 102 into an MPEG video stream again using a well-known MPEG encoding technique, and then controls the block 102. Pass each to For example, the 2x fast backward video stream, the 4x fast backward video stream, and the 8x fast backward video stream are sequentially coded according to the input order and delivered to the control block 102.

Through the above-described process, MPEG video streams for fast forward and fast backward playback corresponding to MPEG video streams of an arbitrary program are generated, respectively, and the control block 102 generates MPEG video streams for fast forward and fast backward playback. Is stored in the secondary storage medium 116 and the storage position information is stored in the buffer memory 108 together with the program index information of the MPEG video stream for fast forward and fast reverse playback.

In other words, the auxiliary storage medium 116 is constituted of a storage medium of substantially the same type as the above-described main storage medium 104, and is required to provide a special playback service according to the present invention, that is, a fast forward or fast reverse playback service. Stores MPEG video streams for fast forward and fast reverse playback, and corresponding Nx fast forward or Nx fast reverse playback MPEG video stream data when required by a Nx fast forward or Nx fast reverse playback service from a client To the control block 102.

On the other hand, the control block 202 in the client DTV 200 includes, for example, a microprocessor to control the overall operation of the DTV, for example MPEG decoding control for a broadcast program provided through a tuner (not shown), Video encoding control, menu generation control, and the like, and also through an interface block (not shown), an MPEG stream, N-times fast forward or N-times fast backward playback MPEG video stream, etc., according to a user's request from a remote server 100 may be used. When provided, control the decoding and display of these video streams.

In addition, the MPEG decoding block 204 may be a coded video stream (i.e., MPEG video stream) of a broadcast program provided through a tuner (not shown) or an on-demand MPEG video stream (or N times fast forward) provided from the control block 202. , An inverse process of encoding the N times MPEG video stream for backward playback, reconstructs the original signal before encoding, and delivers the original signal to the video encoding block 204.

The video encoding block 206 converts the digital video signal of the broadcast program provided by the MPEG decoding block 204, the on-demand video signal, the on-demand video signal for N times fast forward or N times fast backward playback to NTSC or PAL analog. It is converted into a video signal and then transferred to a display side not shown.

Meanwhile, the menu generation block 208 generates menu screen data corresponding to the corresponding mode in response to various control signals provided from the control block 202 in the menu service mode for the user interface and transmits the generated menu screen data to the display side, not shown. In addition, when the menu data for the video on demand is provided from the control block 202, the corresponding menu screen data is configured and transferred to the display side.

Thus, on the monitor on the display side, not shown, a video signal of a tuned broadcast program, an on-demand video signal, an on-demand video signal for fast forward or fast reverse playback, or a composite video signal mixed with a menu screen will be displayed.

Next, a process of providing a fast forward or fast backward playback service of video on demand from a server to a client (DTV) according to the present invention using a client server system having the above-described configuration will be described.

2 is a flowchart illustrating a process of providing a fast forward or fast backward playback service according to a client's request when servicing video on demand from a server to digital television (DTV) according to a preferred embodiment of the present invention.

Referring to Fig. 2, the control block 102 on the server 100 side performs a standby mode (i.e., a standby mode waiting for registration of a new program or waiting for an on-demand service request from a client) (step 302). In step 304, a new program is registered, i.e., whether or not a new program for delivery service to the client is registered in the main storage medium 104.

As a result of the check in the step 304, if a new program is registered, the control block 102 shows program guide information (e.g., program title, director, starring, total running time, summary, etc.) for the newly registered program. Is stored in the memory block 106, and the control information of the registered program, that is, the index information of the registered program and its storage location information, etc. are stored in the buffer memory 108 (step 306). .

Next, the control block 102 fetches (i.e. reads) the MPEG video stream of the newly registered program from the main storage medium 104, and the original video before encoding the MPEG video stream fetched through the decoding block 110. After reconstruction, the reconstructed video stream (i.e., a picture stream of I, B, P pictures) is stored in the temporary memory 112 (step 308).

Further, in the control block 102, for fast forward playback service according to the present invention, n: 1 for generating MPEG video stream for fast forward playback by extracting respective pictures of the video stream stored in the temporary memory 112. Performs picture forward deduction, for example, 2x forward deduction, as shown in FIG. 3, picture 1 of pictures 1 to 3, picture 3, picture 5,---- In order to generate a video stream for double-speed forward playback by forward-decrementing in the order of picture n-1, a video stream for high-speed forward playback such as 4x and 8x is generated (step 310), and N generated as described above. The N-times fast forward playback video streams (picture streams) are respectively encoded into the MPEG video streams in the order of their speed via the encoding block 114 (step 312).

Then, the N N-fold fast forward playback MPEG video streams generated through the above-described process are stored in the auxiliary storage medium 116, and the program index of each N-speed forward playback MPEG video streams generated at the same time. The storage location information along with the information is stored in the buffer memory 108 (step 314).

In addition, in the control block 102, when generation of the preset N N-times fast forward playback MPEG video streams is completed, for the fast backward playback service according to the present invention, the control block 102 of the video stream stored in the temporary memory 112 is completed. Each picture is taken out to perform n: 1 picture backward padding for generation of an MPEG video stream for fast backward playback, for example, from 1 to n times as shown in FIG. 4 times as to reverse video of n pictures, n-2 pictures, n-4 pictures,-----picture 2 in reverse order to create a 2x fast backward video stream Create a video stream for fast backward playback, such as high speed, 8x high speed (step 316), and the N N times fast backward video streams generated in this manner are encoded through the encoding block 114 in MPEG video order. As a stream Each is encoded (step 318).

Then, the N N-times fast backward playback MPEG video streams generated through the above-described process are stored in the secondary storage medium 116, and the program of each N-times fast backward playback MPEG video streams generated at the same time. The storage location information along with the index information is stored in the buffer memory 108 (step 320).

As described above, generation and storage of MPEG video streams for fast forward and fast backward playback corresponding to a newly registered program are then performed at that time in consideration of the load added to the server 100 each time a new program is registered. 322).

In addition, as described above, the process of extracting and decoding the MPEG video stream of the newly registered program, rearranging and encoding pictures, and storing the encoded MPEG video streams for fast forward or fast backward playback on the secondary storage medium 116. Is performed at a time when no load is applied to the server 100, and if a delivery service request message is received from any client during this process, the operation is suspended, and then the delivery service to the client is processed first. . In other words, the delivery service according to the service request has priority over the generation of MPEG video streams for fast forward and fast reverse playback.

On the other hand, the control block 102 checks whether a delivery service (i.e., on-demand video service) request message is received from any client registered during generation of an MPEG video stream for standby mode, fast forward or fast backward playback. (Step 324), if the check here determines that the delivery service request message has been delivered from any client, for example, the DTV 200 shown in Fig. 1, the control information (program index) stored in the buffer memory 108 The MPEG stream of the service requested program is fetched from the main storage medium 104 based on the information and its storage location information) and transmitted to the DTV 200 requesting the delivery service (step 326).

Therefore, on the monitor not shown on the DTV 200 side, the video signal of the program provided from the server 100 will be displayed according to the service request of the user (or viewer).

As described above, when the video of the program provided through the delivery service from the server 100 is being displayed on the monitor of the DTV 200, that is, the MPEG stream of the program that has received the delivery service from the server 100 is DTV. When transmitting to 200, the control block 102 on the server 100 side determines whether or not a special playback service request message is transmitted from the DTV 200 requesting N times fast forward or N times fast backward playback services. Check (step 328).

If it is determined in step 328 that the special playback service request message for requesting N times fast forward or N times fast backward playback service is received from the DTV 200, the control block 102 receives the service request. MPEG video stream for Nx fast forward or Nx fast backward playback corresponding to the program currently being serviced stored in the secondary storage medium 116 with reference to the control information stored in the buffer memory 108 after suspending the delivery service of the program. DTV 200 requesting N times fast forward or N times fast backward playback service by fetching an MPEG video stream for N times fast forward or N times fast backward playback from a position corresponding to when the delivery service is stopped. (Step 330).

Therefore, on the monitor (not shown) on the DTV 200 side, N times fast forward or N times fast backward playback provided from the server 100 in accordance with N times fast forward or N times fast backward playback service request of the user (or viewer). An N times fast forward or N times fast backward video signal reconstructed for the video stream will be displayed, that is, a video signal such as a fast forward mode or a fast rewind mode that is being applied in a typical general VCR.

Next, as described above, while performing the fast forward or fast reverse playback service, the server 100 determines whether a service interruption message is received from the DTV 200 requesting the interruption of the fast forward or fast reverse playback service. Check (step 332), and if the result of the check here is that a service interruption message is received, control block 102 stops the fast forward or fast reverse playback service in response thereto (i.e. MPEG for fast forward or fast reverse playback). The normal delivery service is resumed, i.e., the normal delivery service is fetched and transmitted from the position where the fast forward or fast reverse playback service is interrupted (step 334).

As a result, the on-demand video signal which is normally reproduced again will be displayed on the monitor on the DTV 200 side.

As described above, according to the present invention, each time a new program is registered for the on-demand service in the server, N N times fast forward and N N times fast backward regenerations corresponding to the registered program is considered in consideration of the load state of the server. MPEG video streams are created and stored in the secondary storage medium, and are stored in the MPEG video streams for fast forward and fast backward playback when a special playback service request for fast forward or fast backward playback is requested from a client currently receiving a delivery service. By selecting one to serve as a client, it can greatly reduce the load on the server caused by the fast forward or fast reverse playback service according to the client's request, so that fast forward or fast backward playback without accompanying deterioration of image quality Service to the client It can provide the liver.

Claims (5)

A method of providing a special playback service in a client server system having a server for fetching program data in an MPEG stream including a video stream in a progressive scan mode from a storage medium to a client requesting service in response to a delivery service request. , Each time a new program is registered on the storage medium, N pictures are encoded in the encoded MPEG stream of the registered program by n: 1 to generate N N-fold fast MPEG video streams for later playback, and then stored in the auxiliary storage medium. A first step in which n is a positive integer except 1; The N pictures are encoded in the encoded MPEG stream of the registered program in the reverse order of n: 1 to generate N N times fast backward playback MPEG video streams, and the generated N N times fast backward playback MPEG video streams. A second process of storing n in the auxiliary storage medium, wherein n is a positive integer except 1; A third step of fetching an MPEG stream of a requested program from the storage medium and transmitting it to the service request client when a delivery service is requested from any client; A fourth step of checking whether a fast forward or fast reverse playback service request is received from the service request client while performing the delivery service; Upon receipt of the fast forward or fast reverse playback service request, suspend the delivery service and select one of the plurality of N times fast forward or N times fast backward playback MPEG video streams based on the requested double speed; A fifth step of fetching the selected N-times fast forward or N-times fast backward playback MPEG video stream at a position corresponding to an interruption of a delivery service as a service start point and transmitting the same to the service request client; A sixth process of performing the fifth process until there is a stop request for the fast forward or fast reverse playback service from the client; And If the fast forward or fast reverse playback service interruption request is requested, a special video-on-demand video comprising a seventh process of stopping the fast forward or fast reverse playback service and resuming the delivery service using the position corresponding to the interruption point as a starting point. How to Provide Playback Services. The method of claim 1, wherein the first process comprises: An eleventh step of reconstructing the encoded video pictures in the MPEG stream into an original signal before encoding; A twelve step of generating a picture stream of MPEG video for N times fast forward reproduction by deducting pictures in the reconstructed video stream by n: 1; A thirteenth step of encoding the generated N-times fast forward playback MPEG video picture stream to generate an encoded N-times fast forward playback MPEG video stream and then storing the encoded N-times forward video playback stream on the auxiliary storage medium; And And a fourteenth step of repeating the twelfth and thirteenth steps until N number of N-times fast forward playback MPEG video streams having different speeds are generated. . The method of claim 2, wherein the thirteenth process is: Storing program index information and storage location information of the generated N-times fast forward playback MPEG video stream in another memory space, wherein the stored index information and the storage location information are stored in the fast forward playback service. And a method for searching for a storage position of the generated N-times fast forward playback MPEG video stream upon request. The method of claim 2, wherein the second process is: A twenty-first step of generating a picture stream of MPEG video for N-fold fast backward reproduction by deducting pictures in the reconstructed video stream by n: 1 in the reverse order; A twenty-second step of encoding the generated N-times fast backward playback MPEG video picture stream to generate an encoded N-times fast backward playback MPEG video stream, and storing the encoded N-times backward video playback stream on the auxiliary storage medium; And And a twenty-third process of repeating the twenty-first and twenty-second processes until N number of N-times fast backward playback MPEG video streams having different speeds are generated. . The method of claim 4, wherein the twenty-second process comprises: Storing program index information and storage location information of the generated N-times fast backward playback MPEG video stream in another memory space, wherein the stored index information and the storage location information are stored in the fast backward playback service. A method of providing a special playback service for video on demand, characterized in that it is used to search for a storage position of the generated N-times fast backward playback MPEG video stream.