KR20000033732A - Specific reproduction service providing method of video on demand - Google Patents

Abstract

PURPOSE: A specific reproduction service providing method of a video on demand is provided to decrease a load in a server caused due to backward reproduction service according to a client's demand. CONSTITUTION: A specific reproduction service providing method comprises the steps of: whenever a new program is registered at a storing medium, rearranging video pictures within encoded MPEG(Moving picture experts group) stream of the registered program in a backward order, creating an MPEG video stream for the backward reproduction corresponding to the registered program and storing the created MPEG video stream; when a delivery service is requested by a client, extracting an MPEG video stream corresponding to the requested program from the storing medium and transferring the extracted MPEG video stream to the client; and when a backward reproduction service is received from the client, temporarily stopping the delivery service, extracting the MPEG video stream placed at a position corresponding to the stopped time and transferring the extracted MPEG video stream to the client.

Description

How to provide special playback services for video on demand

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 a 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 backward playback service in response to a user request.

In recent years, with the rapid development of the semiconductor and telecommunications industry, the rapid development of the high-speed information and communication infrastructure, which started from the super highway concept of information, is rapidly spreading. The desire of users to obtain information is increasing, and interactive cable television (I-CATV), which is an advanced form of cable television (CATV), which is commercially available and is widely used as a way to satisfy these needs, In particular, commercial products of interactive digital television are appearing one after another.

On the other hand, instead of analogue, digital, interactive cable television service technology allows video on demand (e.g., program information such as movies) to be delivered instantly on demand. VOD) service is available. In order to realize such 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 high speed 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, a client requests a delivery service such as a program, for example, a movie program, a news program, to a remote server, 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 side 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 the playback service) of MPEG stream from server to client according to the client's request, special playback service like normal analog VCR, e.g. 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. Here, the present invention relates to a backward playback service provided when an on-demand video program is a video signal in a noninterlace mode.

Therefore, when the server requests a special playback service, for example, a backward playback service, on the client side, the server temporarily suspends the normal playback service of the program currently being serviced, and then starts the MPEG stream for backward playback of the service requesting program from that point of time. (Inverted MPEG stream) is generated (i.e., the MPEG stream fetched from the storage medium is decoded and then rearranged and encoded in reverse order to generate an MPEG video stream for backward playback) and transmitted 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 backward playback. As a result of the heavy load on the network, the on-demand video service for other clients becomes a big constraint in providing real time with no latency.

On the other hand, in order to minimize the above-mentioned problems caused when providing a backward playback service in response to a client's request, a deduced backward video MPEG video stream generated by extracting, decoding, and rearranging only the I-picture is applied. It is proposed how to serve as a client.

However, this method can reduce the real-time processing and load load on the server to some extent, but has another problem that a soft backward image is displayed because the continuity of the backward playback image is remarkably dropped on the client side. 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-mentioned problems of the prior art, the video on-demand video on-demand can provide in real time the backward playback service according to the client's request when the video on demand client in the forward scan mode in the form of MPEG stream The purpose of the present invention is to provide a method for providing a special playback service.

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 for providing a special playback service in a network, comprising: rearranging video pictures in an encoded MPEG stream of the registration program in reverse order every time a new program is registered on the storage medium, and corresponding to the registration program. A first step of generating an MPEG video stream and then storing it in an auxiliary storage medium; When a delivery service is requested from an arbitrary client, a second process of fetching an MPEG stream of the requested program from the storage medium and transmitting it to the service request client; A third step of checking whether a backward playback service request is received from the service request client while performing the delivery service; A fourth process of suspending the delivery service, if the backward playback service request is received, fetching the backward playback MPEG video stream at a position corresponding to the interruption time point as a service start point and transmitting the service to the service request client; A fifth step of performing the fourth step until there is a stop request for the backward playback service from the client; And a sixth process of stopping the backward playback service and restarting the delivery service to the service request program when the backward playback service is stopped, when the backward playback service is stopped. Provide a method of providing.

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;

2 is a flowchart illustrating a process of providing a 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;

3 is a diagram illustrating an example of converting a normal picture stream into a picture stream for backward playback in order to provide a 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, and the 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, in the form of a tray N disks each containing a plurality of programs (e.g., movie programs, etc.) compression-coded in an MPEG stream in a noninterlaced mode It is a storage medium to be loaded, and each program data stored therein is prepared for an on-demand video service.

The memory block 106 also includes program guide information for programs that are capable of video-on-demand (ie, programs that are registered and stored in the main storage medium 104), such as program titles, directors, starring, 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 performance of the video-on-demand service, that is, program storage location information, and storage location information of a backward playback program generated for the performance of the present invention. 106 and information storage and deletion in buffer memory 108 are performed by control block 102.

On the other hand, the decoding block 110, when the MPEG video stream is provided from the control block 102 to generate the MPEG video stream for backward playback in the forward scanning mode for providing the backward playback service according to the present invention. Is restored to the original signal before encoding and provided to the control block 102.

In addition, the control block 102 temporarily stores the reconstructed video stream in the temporary memory 112, and then fetches it in the reverse order, that is, the video stream is composed of pictures 1 to n from the starting point. As an example, as shown in FIG. 3, the video stream is re-ordered in the reverse order by fetching the pictures in the order of n pictures, n-1 pictures, n-2 pictures, and -1 pictures. And the reconstructed video streams thus rearranged are provided to the encoding block 114.

Encoding block 114 then encodes the reconstructed video stream provided from control block 102 back into an MPEG video stream using well-known MPEG encoding techniques and then passes it to control block 102.

As described above, an MPEG video stream for backward playback corresponding to an MPEG video stream of an arbitrary program is generated, and the control block 102 stores the generated backward playback MPEG video stream in the auxiliary storage medium 116. At the same time, the storage position information is stored in the buffer memory 108 together with the program index information of the backward playback MPEG video stream.

That is, the secondary storage medium 116 is constituted of a storage medium of substantially the same type as the above-described main storage medium 104, so that the reverse playback MPEG required for providing the special playback service, that is, the backward playback service, according to the present invention. Stores the video streams, and provides to the control block 102 MPEG video stream data for selected backward playback upon request of a backward playback service from the client.

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 furthermore, decoding of these video streams when an MPEG stream or a backward playback MPEG video stream is provided from a remote server 100 through a user interface not shown. Control the display.

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 MPEG for reverse playback) provided from the control block 202. The video stream is subjected to an inverse process of encoding, reconstructed into an original signal before encoding, and transmitted to the video encoding block 204.

The video encoding block 206 converts a digital video signal, an on-demand video signal, or an on-demand video signal for backward playback into an NTSC or PAL analog video signal provided by the MPEG decoding block 204 and then not shown. To the display side.

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 backward reproduction, or a composite video signal mixed with a menu screen will be displayed.

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

FIG. 2 is a flowchart illustrating a process of providing a 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 is performing 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 step 304, if a new program is registered, the control block 102 displays 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 and the storage position information of the registered program, is 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).

In addition, the control block 102 fetches each picture of the video stream stored in the temporary memory 112 in the reverse order, as shown in FIG. 3 as an example. As shown in FIG. Assume that the video stream is rearranged in the reverse order by fetching in the order of picture n, picture n-1, picture n-2, and picture-----1. The reconstructed video streams that are arranged are encoded back into the MPEG video stream via encoding block 114 (step 310).

Then, the backward playback MPEG video stream generated through the above-described process is stored in the secondary storage medium 116, and at the same time, the storage position information together with the program index information of the generated backward playback MPEG video stream is stored. It is stored in the buffer memory 108 (step 312).

As described above, generation and storage of the backward playback MPEG video stream corresponding to the newly registered program is then performed in consideration of the load added to the server 100 each time a new program is registered (step 314).

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 backward video playback MPEG video stream in the auxiliary storage medium 116 may include: If a delivery service request message is received from any client during this process, the operation is suspended and 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 the MPEG video stream for backward reproduction.

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 the generation of the MPEG video stream for standby mode or reverse playback (step 316). If it is determined that the delivery service request message is transmitted from any client, for example, the DTV 200 shown in FIG. 1, the control information (program index information and the storage thereof) stored in the buffer memory 108 is checked. Location information), the MPEG stream of the service requested program is fetched from the main storage medium 104 and transmitted to the DTV 200 requesting the delivery service (step 318).

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 requested the delivery service from the server 100 is DTV. When transmitting to 200, the control block 102 on the server 100 checks whether or not the special playback service request message for requesting the backward playback service is transmitted from the DTV 200 (step 320).

If it is determined in step 320 that the special playback service request message for requesting the reverse playback service is received from the DTV 200, the control block 102 suspends the delivery service of the service request program. Next, with reference to the control information stored in the buffer memory 108, the MPEG video stream for reverse playback corresponding to the program currently being serviced stored in the auxiliary storage medium 116 is fetched, i.e., retracted from the position corresponding to the point where the delivery service is stopped. An MPEG video stream for reproduction is fetched and transmitted to the DTV 200 requesting the backward reproduction service (step 322).

Therefore, on the monitor (not shown) on the side of the DTV 200, a reverse video signal, i.e., a video in which the motion is reversed, is obtained by restoring a backward playback video stream provided from the server 100 in response to a demand of the backward playback service of the user (or viewer). The signal will be displayed.

Next, as described above, while performing the backward playback service, the server 100 checks whether a service interruption message requesting the interruption of the backward playback service is received from the DTV 200 (step 324). As a result of the check here, if a service interruption message is received, the control block 102 responds thereto to interrupt the reverse playback service (i.e., stop transmission of the MPEG video stream for reverse playback) and resume normal delivery service, i.e. A normal delivery service is performed in which the MPEG stream from the position where the backward reproduction service is stopped is fetched and transmitted (step 326).

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, an MPEG video stream for backward playback corresponding to the registered program is generated and stored in the auxiliary storage medium in consideration of the load state of the server. In the server caused by the backward playback service according to the client's request, the client may serve the MPEG video stream for backward playback which is stored in advance when the special playback service request for backward playback is requested from the client currently receiving the delivery service. It can greatly reduce the load of, thus providing the client with a reverse playback service in real time without any deterioration in image quality.

Claims (2)

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, the video pictures in the encoded MPEG stream of the registered program are rearranged in the reverse order to generate an MPEG video stream for backward reproduction corresponding to the registered program and then to the auxiliary storage medium. A first process of storing; When a delivery service is requested from an arbitrary client, a second process of fetching an MPEG stream of the requested program from the storage medium and transmitting it to the service request client; A third step of checking whether a backward playback service request is received from the service request client while performing the delivery service; A fourth process of suspending the delivery service, if the backward playback service request is received, fetching the backward playback MPEG video stream at a position corresponding to the interruption time point as a service start point and transmitting the service to the service request client; A fifth step of performing the fourth step until there is a stop request for the backward playback service from the client; And If there is a request for stopping the backward playback service, providing a special playback service of video on demand consisting of a sixth step of stopping the backward playback service and resuming the delivery service for the service request program using the position corresponding to the stopping point as a starting point. Way. 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 twelfth step of sequentially rearranging the pictures in the reconstructed video stream in reverse order to sequentially generate picture streams of the MPEG video for backward reproduction; A thirteenth step of generating an encoded backward video MPEG video stream by sequentially encoding the picture streams that are sequentially generated; And And a fourteenth step of storing the encoded backward playback MPEG video stream in the auxiliary storage medium.