KR100431897B1 - Method for providing special playback service of video on demand service in interlaced mode - Google Patents

Abstract

The present invention relates to a special playback service technique of a parallel scan mode on-demand video to provide a reverse playback service according to a client's request in real time when serving a video in a streaming scan mode from a server to a client in the form of an MPEG stream. To this end, the present invention, when a new program is registered for the on-demand service to the server, the field conversion corresponding to the registered program in consideration of the load status of the server (the position of the upper field and the lower field in each frame is converted) Creates an MPEG video stream for backward playback in a progressive scan mode and stores it in an auxiliary storage medium. The field is converted to a pre-generated field-converted interactive scan mode when a special playback service request for backward playback is requested from a client currently receiving a delivery service. Client MPEG video stream for reverse playback In addition, it is possible to greatly reduce the load on the server caused by the backward playback service according to the client's request, thereby providing the backward playback service to the client in real time without deterioration in image quality, and also for backward playback. By converting the position of the upper field and the lower field of each frame in the MPEG video stream for each other, it is possible to reliably prevent the screen of the backward playback video reproduced through the monitor on the client side.

Description

METHOD FOR PROVIDING SPECIAL PLAYBACK SERVICE OF VIDEO ON DEMAND SERVICE IN INTERLACED MODE}

The present invention relates to a method of providing a video on demand (VOD) service to a client in a remote server, and more particularly, to provide a VOD service of interlace video from a server to a digital television (DTV). And a special playback service method of the interlocking scan mode 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 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 a digital TV (I-CATV), which is an advanced form of cable television (CATV), which has been commercialized and widely used as a way of satisfying these needs, especially Commercial products for interactive digital television are appearing one after another.

On the other hand, the use of digital interactive cable television service technology instead of analogue means that video-on-demand (on-demand, video, etc.) information can be delivered on demand at the desired time. VOD) service is available. In order to realize such an on-demand video service, an information provider composed 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 There is a need for a delivery system provider for delivering simultaneously to multiple television users and for a television user to use (or use) service information provided from the delivery system provider.

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, which 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, 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 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. Here, the present invention relates to a backward playback service provided when an on-demand video program is a video signal in an interlace 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 major limitation in providing real-time without waiting.

On the other hand, the video signal in the parallel scan mode is composed of a frame string consisting of an upper field and a lower field, and a single complete video frame is displayed by scanning the upper field and the lower field. Here, the order in which the field signals are displayed is the upper field, lower field, upper field, lower field,---. That is, as shown in FIG. 4 as an example, the 1, 3, 5, 7, and 9 fields in the five frames F1 to F5 are upper fields, and the 2, 4, 6, 8, and 10 fields are lower fields. In this case, the display order of these fields is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

On the other hand, in the above-described conventional method, only the frames are rearranged in reverse order during the reverse playback service, as shown in the lower part of FIG. 4 as an example, five frames of F5, F4, F3, F2, and F1. The rearranged rearward video signals of the progressive scan mode are rearranged in order, and the rearward rearward video signals of the rearranged conventional scan mode are sequentially transmitted (i.e., 9, 10, 7, 8, 5 in the field concept). , 6, 3, 4, 1, 2) in order to display the reverse playback video signal of the on-demand scan mode video on demand according to the user's request, i.e. 9, 10, 7, 8, 5 The video signals are displayed in the field order of 6, 3, 4, 1, 2.

However, in the case of backward image (i.e. image with backward movement), the display of natural and smooth reverse image is realized when scanned in the field order of 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. In the case of displaying backward playback video in the conventional scanning mode according to the conventional method, since the video signals are scanned on the monitor in the field order of 9, 10, 7, 8, 5, 6, 3, 4, 1, 2. There is a problem that an unsmooth image causes a display, that is, a screen shaking.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and when the on-demand video mode of the server in the client on-demand scan service in the form of MPEG stream, the interlocking scan mode that can provide a reverse playback service according to the client's requirements in real time. Its purpose is to provide a special playback service method for video on demand.

It is another object of the present invention to provide a special playback service method of an on-demand scan mode on-demand video that can serve a smooth backward playback video that does not cause screen shaking when the on-demand playback video on an on-demand scan mode from a server to a client is provided. There is.

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 a perpetual scan mode from a storage medium to a client requesting a service in response to a delivery service request. A method of serving a special playback in a network, the method comprising: rearranging video frames in an MPEG stream of the registered program in reverse order every time a new program is registered to the storage medium, and an upper field and a lower field in each rearranged video frame. A first step of converting positions of each other to generate an MPEG video stream for backward reproduction in the field-converted interlaced scanning mode, and then storing the encoded video stream in an auxiliary storage medium; When a delivery service is requested from an arbitrary client, a second step of extracting the accompaniment scanning mode 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; When the backward playback service request is received, the delivery service is suspended, and the MPEG video stream for backward playback in the field-converted interlaced scanning mode located at a position corresponding to the interruption time point is fetched as a service starting point, thereby providing the service request client. A fourth process of transmitting to; 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 resuming the delivery service based on a position corresponding to the interruption point when the backward playback service stop request is made. to provide.

1 is a schematic block diagram of a client server system suitable for providing a special playback service of video on demand with a progressive scan mode 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 a video on demand in a scanning scan mode from a server to a digital television (DTV) according to a preferred embodiment of the present invention;

FIG. 3 is a diagram illustrating an example of converting a frame having two fields into a field conversion frame in which positions of an upper field and a lower field are changed according to the present invention for providing a backward reproduction service of a progressive scan image; FIG.

4 is a diagram illustrating an example of converting a frame having two fields into a field conversion frame in which positions of an upper field and a lower field are changed according to the conventional method for providing a backward reproduction service of a progressive scan image.

<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 a digital television according to the present invention, the server 100 and a client such as a digital television (DTV) 200; ).

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 a request signal is received, a MPEG stream of a program for which a service is requested is transmitted to a client through an interface block.

Here, the main storage medium 104 is, for example, N disks each containing a plurality of programs (e.g. movie programs, etc.) compression-coded into an MPEG stream in the interlaced 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. Program guide information, such as an overview, and the like, is stored, and the on-demand video menu data is fetched at the request of the menu service from the client and transmitted through the control block 102 to the client requesting the menu service. 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 is provided with the MPEG video stream when the MPEG video stream is provided from the control block 102 to generate the MPEG video stream for backward playback mode in order to provide the backward playback service according to the present invention. That is, the upper and lower field streams in the interlocking scan mode are restored to the original signal before encoding and provided to the control block 102.

Further, the control block 102 temporarily stores the reconstructed video stream in the temporary memory 112, and then fetches it in the reverse order, assuming five frames, as shown in FIG. 3 as an example. , F4, F3, F2, F1, each frame is fetched, and the position of the upper field and the lower field in each fetched frame is converted, for example, in the case of F5 frame, field 9, which is actually the upper field, is converted to the lower field. In addition, a field transform frame is generated by making field 10, which is actually a lower field, as an upper field, and the video frames of the field transformed interlocking scan mode are provided to the encoding block 114.

The encoding block 114 then converts the reconstructed video stream provided from the control block 102, i.e., the video frames of the field transformed collateral scan mode, back into the MPEG video stream in the collateral scan mode using a well-known MPEG encoding technique. The code is then passed to the control block 102.

Through the above-described process, the MPEG video stream for the reverse playback of the field-converted parallel scan mode corresponding to the MPEG video stream of the arbitrary program is generated, and the control block 102 generates the MPEG for the reverse playback in the conventional scanning mode. The video stream 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 backward reproduction.

That is, the secondary storage medium 116 is composed of storage mediums of substantially the same type as the above-described main storage medium 104, so that the field-converted fighting required for providing the special reproduction service, that is, the reverse reproduction service, according to the present invention. Stores the reverse video playback MPEG video streams in the scan mode, and provides the control block 102 with the field-converted backward playback MPEG video stream data in the field-converted scanning mode upon request of the 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), Performs video encoding control, menu generation control and the like, and also, MPEG video in a parallel scan mode or backward-converted MPEG video in a field-converted parallel scan mode according to a user's request from a remote server 100 through an interface block (not shown). Control the decoding and display of these video streams when the stream is provided.

In addition, the MPEG decoding block 204 may be an encoded video stream (i.e., MPEG video stream) of a broadcast program provided through a tuner (not shown) or an MPEG video stream (or field) in a conventional scan mode provided from the control block 202. An inverse process of encoding is performed on the converted decoding video MPEG video stream in the progressive scanning mode, and the original signal before encoding is restored and transmitted to the video encoding block 204.

In the video encoding block 206, the digital video signal of the broadcast program provided in the MPEG decoding block 204, an on-demand video signal in the interlaced scan mode, or an on-demand video signal for the reverse playback in the field-converted interlaced scan mode are NTSC. Or it converts to a PAL analog video signal and passes it to the 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 delivered 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, a field-converted on-demand video signal for playback 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 a video on demand in a scanning scan mode from a server to a 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 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 MPEG video stream of the conventional scan mode, which is fetched through the decoding block 110, That is, the frame stream of the upper field and the lower field is restored to the original signal before encoding, and then the restored video stream (that is, the frame stream of the upper field and the lower field) is stored in the temporary memory 112 (step 308).

Further, the control block 102 fetches each frame of the video stream stored in the temporary memory 112 in the reverse order, assuming five frames, as shown in FIG. 3 as an example. F5, F4, F3 Extract the frames in the order of F2, F1 and rearrange the frames in the reverse order (step 310), and convert the positions of the upper field and the lower field in each of the extracted frames, e.g. A field transform frame is generated by making field 9 a lower field and field 10, which is a lower field, as an upper field (step 312). The video frames of the field-transformed conventional scanning mode thus encode the encoding block 114. Is encoded back into the MPEG video stream in a perpetual scanning mode (step 314).

Then, the MPEG video stream for backward reproduction in the progressive scan mode generated through the above-described process is stored in the auxiliary storage medium 116, and the program index of the MPEG video stream for backward reproduction in the progressive scan mode generated at the same time. The storage location information along with the information is stored in the buffer memory 108.

As described above, the generation and storage of the MPEG video stream for backward reproduction in the progressive scan mode corresponding to the newly registered program are then performed in consideration of the load added to the server 100 each time a new program is registered (step 316).

In addition, as described above, the MPEG video stream of the newly registered program is fetched and decoded, rearranged frames, transformed fields are encoded, and then auxiliary storage of the encoded MPEG video stream for backward playback in the encoded conventional scan mode. The process of storing in the medium 116 is performed at a time when the server 100 is not overloaded. If a delivery service request message is received from any client during the process, the operation is suspended and then the client is suspended. Prioritize the delivery service to the furnace. 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 or not a delivery service (i.e., on-demand video service) request message is received from any registered client during generation of the MPEG video stream for backward playback in standby mode or caterpillar scan mode. (Step 318) If the check here determines that a 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 Information, and the storage scanning mode MPEG stream of the service-required program is fetched from the main storage medium 104 and transmitted to the DTV 200 requesting the delivery service (step 320).

Therefore, on the monitor (not shown) on the DTV 200 side, the parabolic scan mode 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 interlocking scan mode MPEG of the program that is requested to the delivery service from the server 100. When the stream is being transmitted to the DTV 200, the control block 102 on the server 100 checks whether or not a special reproduction service request message for requesting the reverse reproduction service is transmitted from the DTV 200 (step 322). ).

If it is determined in step 322 that the special playback service request message for requesting the backward 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 the reverse playback of the field-converted interlaced scanning mode corresponding to the currently serving program stored in the auxiliary storage medium 116 is fetched, i.e., the delivery service is stopped. The MPEG video stream for backward playback in the field-transformed progressive scan mode is fetched from the position corresponding to the viewpoint and transmitted to the DTV 200 requesting the backward playback service (step 324).

That is, based on the frame signal before the field conversion, the MPEG video stream provided to the client in the backward playback service according to the present invention is transmitted in the order of the lower field, the upper field, the lower field, and the upper field---. .

Therefore, on the monitor (not shown) on the DTV 200 side, the reverse video signal is obtained by reconstructing the video stream for the reverse playback of the field-converted-parallel scanning mode provided from the server 100 in response to the request of the backward playback service of the user (or viewer). Is displayed. That is, according to the backward reproduction service method of the present invention, as shown in FIG. 3 as an example, the order of 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 (ie, before field conversion). In the conventional method, since field data is displayed on the monitor in the order of the frame signal in the order of the lower field 10, the upper field 9, the lower field 8, the upper field 7, and the order of---). As a problem of shaking the playback screen is reliably prevented as described above, users can be provided with a natural and smooth backward screen.

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 326). As a result of the check here, when a service interruption message is received, the control block 102 stops the reverse playback service in response to it (i.e., stops transmitting the MPEG video stream for backward playback in the field-converted interlaced scan mode). The normal delivery service is resumed, i.e., the normal delivery service is fetched from the position where the backward reproduction service is stopped, and the conventional delivery service is fetched and transmitted (step 328).

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, the MPEG video stream for the reverse playback of the field-converted-parallel scanning mode corresponding to the registered program is generated in consideration of the load state of the server. And store it in the secondary storage medium, and serve the client a field-converted MPEG video stream for backward playback, which is generated in advance when a special playback service request for backward playback is received from the client currently receiving the delivery service. As a result, it is possible to greatly reduce the load on the server caused by the backward playback service according to the client's request, thereby providing the backward playback service to the client in real time.

In addition, the present invention can reliably block the screen of the backward playback video played through the monitor on the client side by converting positions of the upper field and the lower field of each frame in the backward playback MPEG video stream, A natural, smooth reverse image can be provided.

Claims (4)

Claims [1] A method for servicing special playback in a client server system having a server for fetching program data in an MPEG stream including a video stream in a batting scan mode from a storage medium and transmitting the same to a client requesting a service in response to a delivery service request. Whenever a new program is registered in the storage medium, the video frames in the MPEG stream of the registered program are rearranged in the reverse order, the positions of the upper field and the lower field in each rearranged video frame are converted to each other, and the field converted A first step of generating an MPEG video stream for backward reproduction in a progressive scan mode and then storing it in an auxiliary storage medium; When a delivery service is requested from an arbitrary client, a second step of extracting the accompaniment scanning mode 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; When the backward playback service request is received, the delivery service is suspended, and the MPEG video stream for backward playback in the field-converted interlaced scanning mode located at a position corresponding to the interruption time point is fetched as a service starting point, thereby providing the service request client. A fourth process of transmitting to; 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 reverse playback service and resuming the delivery service based on a position corresponding to the interruption time point when the backward playback service stop request is made; Special playback service method of the on-demand scan mode on-demand video. The method of claim 1, wherein the first process comprises: An eleventh step of restoring video frames in the MPEG stream to an original signal before encoding; A twelfth step of sequentially rearranging frames in the reconstructed video stream in reverse order to sequentially generate frame streams of the MPEG video for backward reproduction in a progressive scan mode; A thirteenth step of converting positions of the upper field and the lower field in each of the generated video frames to each other to generate an MPEG video stream for backward reproduction of the field-converted-parallel scanning mode; And A fourteenth step of encoding the backward-converted MPEG video stream of the field-converted parallel scanning mode by MPEG encoding and then storing the encoded video stream in the auxiliary storage medium; Special playback service method of the interlocking scan mode video on demand characterized in that it comprises a. The method of claim 2, wherein the fourteenth step further includes storing program index information and storage location information of the MPEG video stream for backward playback in the field-converted parallel scanning mode in another memory space. The index information and its storage position information are used for searching for a storage position of the backward-converted MPEG video stream of the field-converted-parallel scanning mode when the backward-playing service request is made. Service method. 4. The field-transformed accompaniment scan according to any one of claims 1 to 3, wherein the service method further comprises, if a delivery service is requested from another client during the generation of the MPEG video stream for backward reproduction of the field-converted collateral scan. 11. A method of special playback service for an on-demand scan mode video on demand, characterized in that the generation of the MPEG video stream for backward playback in mode is suspended, and then the delivery service to the other clients is first performed.