JP2000125260A - Moving picture transmission server, moving picture transmission system using the server and moving picture transmission control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize reverse reproduction of a moving picture in the moving picture transmission system where a moving picture that is coded and stored in a server is transmitted to a client terminal and displayed thereon. SOLUTION: A moving picture transmission server 13 prepares a multiplexing file 31 where an original image for standard reproduction is coded temporally in a forward sequence and a multiplexing file 82 where the same original image for reverse reproduction is coded temporally in a reverse sequence. When the server 13 receives time information from a client terminal 10-on the way of transmission of the moving picture by using the multiplexing file 31, the multiplexing file 32 is selected and the moving picture transmission using the multiplexing file 32 is started. When a reproduction time on a time base of the moving picture in the multiplexing file 32 reaches the past time designated by the time information, the multiplexing file 31 for standard respectively is selected again, and the moving picture transmission using the multiplexing file 31 is restarted from a position corresponding to the past time designated by the time information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture transmission server for streaming reproduction of a moving picture file on a client terminal, a moving picture transmission system using the server, and a moving picture transmission control method.

[0002]

2. Description of the Related Art In recent years, a technology for distributing a moving image file from a server to a client terminal via a network such as the Internet has begun to be developed. In such a moving image transmission system, a technique called streaming reproduction (or streaming data transfer) is used. The streaming reproduction is a format in which the reproduction is not started after all the data of the moving image file is taken into the client terminal, but is reproduced on the client terminal side each time the data arrives.

[0003] That is, when a user on the client terminal side selects a moving image file stored in the server,
The download of the moving image file is started by the server. Then, on the client terminal side, the reproduction is performed in real time while downloading the moving image file.

However, in the conventional system, the server which has received a file designation from the client terminal only needs to start downloading an encoded file for standard reproduction in which a moving image is temporally encoded in the forward direction. is there. For this reason, the normal standard reproduction process of reproducing a moving image temporally in the forward direction can be easily performed on the client terminal side, but a user of the client terminal side wants to view a temporally past video. In such a case, processing such as re-downloading the encoded file from the beginning is required, and it has been difficult to return to the past video.

[0005] In a moving image transmission system using streaming reproduction, special reproduction such as reverse reproduction, slow reproduction, high-speed reproduction, and frame-by-frame reproduction is not realized. In the case of a system in which all data of a moving image file is imported to the client terminal and then the reproduction is started, a special reproduction function can be provided on the client terminal side.However, in a moving image transmission system using streaming reproduction, As described above, since it is necessary for the client terminal to decode and reproduce a moving image in real time, it is difficult to realize such special reproduction on the client terminal side.

[0006]

As described above, conventionally, only encoded files for standard reproduction in which moving images are temporally encoded in the forward direction are prepared on the server side. Even when the user wants to confirm the past portion of the video currently being viewed again, it is practically difficult to return to the past video. Also, special reproduction such as reverse reproduction, slow reproduction, high-speed reproduction, and frame-by-frame reproduction has not been realized.

[0007] The present invention has been made in view of such a point, and when a user of a client terminal wants to re-view a past portion of a currently-viewed video, an encoded file of a moving image is converted. It is an object of the present invention to provide a moving image transmission server, a moving image transmission system using the server, and a moving image transmission control method capable of checking and returning a video to a past portion specified by a user without re-downloading. And

Further, the present invention provides a moving image transmission server capable of easily realizing special reproduction such as reverse reproduction, slow reproduction, and frame-by-frame reproduction only by a server-side function, a moving image transmission system using the server, and a moving image. It is an object to provide an image transmission control method.

[0009]

In order to solve the above-mentioned problems, the present invention provides a moving image transmission server for storing moving images and transmitting the stored moving images to a client terminal. A first encoded file for standard reproduction obtained by temporally encoding in the forward direction, and a second encoded file for reverse reproduction obtained by temporally encoding the moving image in the reverse direction. Encoding file, and a moving image transmission control means for selectively transmitting the moving image to the client terminal using the first and second encoded files, in response to a request from the client terminal, A moving image transmission control means for switching an encoded file used for moving image transmission between the first encoded file and the second encoded file is provided.

In this moving image transmission server, a first coded file for standard reproduction and a second coded file for reverse reproduction are prepared for the same moving image. If the user wants to see the past part of the video currently being viewed again, the server switches from the first encoded file to the second encoded file so that the user of the client terminal can specify It is possible to return the image while checking the image in the reverse direction to the past position.

The switching of the encoded file by the moving image transmission control means can be controlled using time information input from the client terminal. In this case, during the moving image transmission period using the first coded file, the moving image transmission control means performs a time indicating a time earlier in time than the current reproduction time on the time axis of the moving image. When information is input from the client terminal, an encoded file used for the moving image transmission is switched from the first encoded file to the second encoded file. Then, the moving image transmission using the second encoded file is executed until the reproduction time on the time axis of the moving image returns to the past time specified by the time information.

[0012] The moving image transmission control means may be configured to transmit the moving image using the second encoded file until the reproduction time on the time axis of the moving image returns to the past time specified by the time information. Is executed, the encoded file used for moving image transmission is converted from the second encoded file to the first encoded file.
Means for switching to the encoded file of the above, and the moving image transmission using the first encoded file is restarted from the past time specified by the time information.

[0013] Thus, after returning to the past position specified by the user of the client terminal while confirming the backward image, it is possible to automatically resume normal forward reproduction from that position.

It is preferable that each of the first and second encoded files is composed of an encoded stream into which an intra-frame encoded picture is inserted at a constant period. In this case, the moving image transmission control means transmits only the intra-coded picture of the first encoded file when performing high-speed reproduction of the moving image, and the second code when performing high-speed reverse reproduction. Only the intra-frame coded pictures of the encoded file are transmitted. Thereby, high-speed reproduction and high-speed reverse reproduction can be easily realized.

The server may further include, in addition to the first and second encoded files, an encoded file for slow reproduction in which the moving image is encoded for slow reproduction, and a file for frame-by-frame reproduction of the moving image. It is preferable to prepare an encoded file for frame-by-frame playback which is encoded in advance. This makes it possible to provide various special reproduction services such as slow reproduction and frame-by-frame reproduction in addition to reverse reproduction.

Also, the present invention provides a standard reproduction coding system for storing a moving image and transmitting the stored moving image to a client terminal by encoding the moving image for standard reproduction. Files, a plurality of special reproduction encoded files obtained by respectively encoding the moving images for a plurality of different special reproductions, and the standard reproduction encoded file according to a reproduction mode designated by the client terminal. Means for selecting an encoded file to be used for moving image transmission from the plurality of encoded files for trick play, and transmitting a moving image to the client terminal using the selected encoded file. It is characterized by.

In this moving image transmission server, dedicated encoded files are individually prepared for each special reproduction mode to be served, and these encoded files are selectively selected according to the reproduction mode designated by the client terminal. Used for As a result, various special reproductions including reverse reproduction, slow reproduction, frame-by-frame reproduction, and the like can be easily realized even in a system mode using streaming reproduction in which a moving image stream is downloaded from a server and reproduced in real time. be able to.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration of a moving image transmission system according to an embodiment of the present invention.
In this moving image transmission system, the client terminal 10-1 has a GSTN line # 1 and a general analog telephone network GSTN (General Switched).
It is connected to a gateway 11 via a Telephone Network 2. Similarly, the client terminal 10-2 is connected to the gateway 11 via the ISDN line # 2 and ISDN3, and the client terminal 10-3 is connected to the gateway 11 via the PHS radio transmission line # 3 and the PHS network 4. The gateway 11 is connected to the network 1 such as the Internet via a dedicated line # 4 or the like. These client terminals 10-1 to 10-3 are each realized by a personal computer, a workstation, a PDA, or the like.

On the other hand, the moving image transmission server 13 is connected to the router 12 via a part # 6 of the LAN, and the router 12 is connected to a dedicated line #
5 is connected to a network 1 such as the Internet. The moving image transmission server 13 includes a multiplexed file 31 (for standard reproduction) including a moving image encoded stream obtained by temporally encoding the original image in the forward direction, and the same original image as that of the multiplexed file 31. A multiplexed file 32 (for reverse reproduction) including a moving image encoded stream encoded in the direction is provided.

In the multiplexed file 31, a coded video stream and a coded stream of audio data coded in the temporally forward direction are multiplexed. As for the multiplexed file 32, only a moving picture coded stream temporally coded in the reverse direction may be multiplexed as multiplexed data. The multiplexing is not limited to images and sounds, and multiplexing such as character data may be performed.

The encoded video stream included in the multiplexed file 31 is a stream for standard reproduction for reproducing a moving image in a temporally forward direction. As shown in FIG. An input frame (f0, f1, f2, f2) of an original image is encoded using a predictive coding method such as MPEG2.
3, f4,... Fn, fn + 1, fn + 2) are temporally encoded in the forward direction. Here, the temporally forward direction means that encoding is performed in the input frame order of the original image, and does not limit the prediction order of P pictures and B pictures.

The coded video stream included in the multiplexed file 32 is used for reverse reproduction (reverse reproduction), and as shown in FIG. Is realized by encoding the original image in the temporally reverse direction (encoding from the last frame of the original image to the first frame). Also in this case, the prediction order of P pictures and B pictures is not limited.

The coded video stream included in the multiplexed file 32 reproduces, for example, a VCR in the reverse direction and converts a moving image from the VCR input in a temporally reverse direction into an MPEG-2 video.
It can be realized by encoding with a predictive encoding method such as

The beginning and end of the moving picture coded stream of the standard reproduction multiplex file 31 correspond to the temporally past position and the latest position of the original image, respectively. For, the beginning and end of the encoded video stream correspond to the temporally newest position and the oldest position of the original image, respectively. By transmitting the moving image encoded stream of the multiplexed file 31 sequentially from the beginning, the position on the time axis of the reproduced moving image temporally advances. On the other hand, when the moving picture encoded stream of the multiplexed file 32 is transmitted in order from the beginning, the position on the time axis of the reproduced moving picture temporally returns to the past direction.

In both the multiplexed files 31 and 32, the encoded video stream contains reproduction time information indicating the position on the time axis of the original image. Regarding the multiplex file 31 for standard reproduction, the value represented by the reproduction time information changes in a direction temporally proceeding from the head of the stream to the end of the stream.
For 2, the value represented by the reproduction time information changes in a direction temporally returning to the past from the head of the stream to the end.

In addition, intra (I) pictures of intra-frame coding are inserted into the coded video streams of the multiplexed files 31 and 32 at regular intervals. The coding rate depends on the transmission path.

In the present embodiment, an intra (I) picture is used as a random access point, fast-forward playback (high-speed playback) of a moving image using a multiplexed file 31, and a moving image using a multiplexed file 32. It is also used for fast-forward reverse playback (high-speed reverse playback).

That is, when fast-forward playback (high-speed playback) is performed using the coded video stream of the multiplexed file 31, only I-pictures are sequentially read out of the multiplexed file 31 and read. The data is transmitted from the transmission server 13 to the client terminal. Also, when performing fast-forward reverse playback (high-speed reverse playback) using the moving picture coded stream of the multiplexed file 32, only I-pictures are sequentially read from the multiplexed file 32 and are read from the server to the client. Transmitted to the terminal.

FIG. 3 shows client terminals 10-1 to 10
FIG. 3 is a block diagram showing a functional configuration of a streaming playback software viewer executed in the third embodiment. The multiplexed data transmitted from the moving image transmission server 13 is first buffered in the input buffer 21 of the client terminal, and then passed to the demultiplexing unit 22. Demultiplexing unit 22
Separates the multiplexed coded stream into image data and audio data, and
Respectively to send the encoded data. The image decoding unit 23 decodes the image data and sends the decoded data to the image buffer 25. Similarly, the audio decoding unit 24 decodes the audio data and sends the decoded data to the audio buffer 26. The image buffer 25 and the audio buffer 26 include an image decoding unit 23 and an audio decoding unit 24.
And plays the role of synchronizing the image and the audio. The synchronized image and audio data are output as an image and audio from the display 27 and the speaker 28 of the client terminal, respectively.

On the GUI operation screen displayed on the display 27 by the software viewer, a slide bar 20 and command buttons 30 for controlling various playback modes are displayed.
Is arranged.

The slide bar 20 indicates the current playback position with respect to the entire length of the file being played (total playback time), and the slide bar 20 is slid right by a mouse operation or the like by the user of the client terminal. Means that the reproduction position is advanced in time, and sliding to the left means that the reproduction position is temporally returned to the past. The direction and amount by which the slide bar 20 is slid are detected by the control unit 29, and are notified to the video transmission server 13 as time information for video playback control.

For example, when the slide bar 20 is slid to the left, the time information indicating a time earlier than the current reproduction time on the time axis of the moving image is transmitted to the control unit 29.
Is sent to the moving image transmission server 13. In this case, the time specified by the time information is a value that is retroactive to the time corresponding to the slide amount of the slide bar 20 from the current reproduction time on the time axis of the moving image. The current playback time on the time axis of the moving image is stored in the input buffer 21.
Is provided by the reproduction time information included in the data buffered in.

The time information from the control unit 29 is transferred from a multiplexed file 31 for standard reproduction coded in the forward direction in time to a multiplexed file 32 for reverse reproduction coded in the backward direction in time. Of the multiplexed file 32 encoded in the reverse direction in time, and information specifying the reproduction end time, and the like.

The command button 30 is for instructing a reproduction mode, and includes a standard reproduction button, a reverse reproduction button, a high-speed reproduction button, a high-speed reverse reproduction button,
A button for slow playback, a button for frame-by-frame playback, and the like are arranged. When the user of the client terminal selects a button by operating a mouse or the like, a playback mode instruction command corresponding to the button is transmitted from the control unit 29 to the moving image transmission server 13.

The multiplexed file 31 described above is used for fast-forward playback (high-speed playback), standard playback, slow playback, and frame-forward playback, and the multiplexed file 31 is used for reverse playback and fast-forward reverse playback (high-speed reverse playback). 32 are used.

FIG. 4 shows the internal configuration of the moving image transmission server 13. The moving image transmission server 13 selectively transmits the moving image to the client terminals 10-1 to 10-3 by using the multiplexed files 31 and 32 described above. In response to a request given from the client terminals 10-1 to 10-3 by operation, the multiplexed file 3 for standard reproduction
A multiplexed file changeover switch 41 for switching a file to be used between 1 and a multiplexed file 32 for reverse reproduction is provided. The multiplex files 31 and 3 described above are used.
The two types of files are actually the moving image transmission server 1
3 is prepared individually for each content to be distributed by the distribution service, and a multiplexed file 31 coded for standard reproduction and a multiplexed file 32 coded for reverse reproduction for each content. Is switched by the multiplexed file changeover switch 41.

The above is the configuration of the present embodiment. Next, the operation will be described. First, for example, the client terminal 10
When the user who owns -1 uses the image distribution service with sound by the moving image transmission system, the GSTN line #
1 accesses the Internet service provider on the GSTN 2 via the GSTN 2, for example. The provider connects the network 1 and the line via the gateway 11. Then, the client terminal 10-1 can exchange data bidirectionally with the Internet network via the gateway 11. So, for example, W
The user accesses the address that provides the moving image transmission service on the web, and stores the file (content) that the user wants to see in W
A streaming reproduction is performed in which the reproduction is performed while being selected and downloaded on the eb. On the other hand, the moving image transmission server 13 acquires the content information selected by the client terminal 10-1 from the network 1 via the router 12, and starts transmitting the moving image to the client terminal 10-1. In this case, usually, moving image transmission is started using the multiplex file 31 for standard reproduction corresponding to the selected content.

In this state, the client terminal 10-1
Performs demultiplexing and decoding of image and audio data while starting buffering of multiplexed data in the input buffer 21. If the user of the client terminal 10-1 has a desire to see the past video that has already been reproduced, the user of the client terminal 10-1 can use the slide bar 20 on the software viewer.
Slide to the left. The control unit 29 detects the sliding direction and the amount of the slide bar 20 and notifies the moving image transmission server 13 of the detection as time information.

Based on the time information notified from the client terminal 10-1, the moving image transmission server 13 switches the multiplex file used for moving image transmission from the multiplex file 31 for standard reproduction to the multiplex file switch 41. Switching to the multiplexed file 32 for reverse reproduction, and moving image transmission is performed using the multiplexed file 32 until the time comes back to the past reproduction time specified by the time information. When the playback time reaches the past playback time specified by the time information, the moving image transmission server 13 uses the multiplexing file switch 41 to switch the multiplexing file to be used for moving image transmission again to the multiplexing file 31 for standard playback.
And the moving image transmission using the multiplexed file 31 is restarted from the past reproduction time specified by the time information.

FIG. 5 shows a state of the reverse reproduction process accompanied by the switching of the multiplexed file. In FIG. 5, the reproduction time on the time axis of the moving image is shifted from the current reproduction time “70” on the multiplexed file 31 to a position “50” which is temporally earlier than the current reproduction time “70” by sliding the slide bar 20 to the left. It is assumed to return to.

In this case, the file to be used is switched from the multiplex file 31 to the multiplex file 32.
The multiplexed file 32 is advanced (skipped) from the beginning to the position of the reproduction time “70”, and the reading of the encoded stream is started from the I picture corresponding to the reproduction time “70”.

When the reproduction time on the time axis of the moving image of the multiplexed file 32 becomes "50", the moving image transmission using the multiplexed file 32 for reverse reproduction is terminated. Then, the moving image transmission using the multiplexed file 31 is performed at the reproduction time “5”.
The processing is restarted from the position of the I picture corresponding to "0".

If the fast reverse playback mode is designated by the command button 30 when the slide bar 20 is slid left, only I-pictures belonging to a range corresponding to playback times "70" to "50" are multiplexed. It is read from the encoded stream of the encrypted file 32 and transmitted to the client terminal 10-1.

On the other hand, when the user of the client terminal 10-1 uses the slide bar 20 on the software viewer,
Is slid to the right, the multiplex file used for moving image transmission is not switched, and moving image transmission using the multiplex file 31 for standard reproduction is continued. In this case, the multiplexed file 31 is forwarded (skipped) up to the portion indicated by the time information, and transmission is resumed from there. However, only the I picture is read from the multiplexed file 31 and high-speed reproduction is performed up to the portion indicated by the time information. The processing may be performed.

Next, referring to the flowchart of FIG.
The procedure of the moving image transmission control process by the moving image transmission server 13 will be described. When the time information is not input from the client terminal 10-1 (NO in step S101), the moving image transmission server 13 performs the moving image transmission using the multiplex file 31 for standard reproduction as usual (step S1).
02). If time information is input from the client terminal 10-1 during moving image transmission using the multiplexed file 31 (YES in step S101), the moving image transmission server 13
Represents the current playback time (T) indicated by the playback time information corresponding to the currently transmitted data included in the encoded stream of the multiplexed file 31 and the playback time (t) specified by the time information. Then, it is determined whether or not the reproduction time (t) specified by the time information is temporally past the current reproduction time (T) (steps S103 and S10).
4).

Playback time (t) specified by time information
Is temporally past the current reproduction time (T) (YES in step S104), the moving image transmission server 13
Is switched to the multiplexed file 32 for reverse reproduction by the multiplexed file changeover switch 41, and the moving image transmission using the multiplexed file 32 is started from the current reproduction time (T) (step S105). If the current playback time (T) specified by the playback time information corresponding to the data currently being transmitted included in the encoded stream of the multiplexed file 32 matches the playback time (t) specified by the time information (step S
106), the moving image transmission server 13 switches to the multiplexing file 31 again by the multiplexing file changeover switch 41, and restarts the moving image transmission using the multiplexing file 31 from the current reproduction time (T = t). (Step S10
7).

On the other hand, if the playback time (t) specified by the time information is temporally ahead of the current playback time (T) (NO in step S104), the moving image transmission server 13 The multiplexed file 31 is advanced (skipped) until the reproduction time (t) specified by the time information (step S108).

The switching between the moving image transmission using the multiplexed file 31 and the moving image transmission using the multiplexed file 32 can also be performed by operating the command button 30.

As shown in FIG. 7, in addition to the multiplex file 32 for reverse reproduction, a multiplex file (for slow reproduction) 33 encoded for slow reproduction as a file for special reproduction, and a frame-by-frame reproduction Multiplexed file (for frame-by-frame playback) 34 encoded for
May be provided.

The multiplexed file 33 for slow reproduction is a coded file for slow reproduction of the original image temporally in the forward direction. For example, a VCR is reproduced slowly, and as shown in FIG. If the input moving image from the VCR whose input frame is switched is predicted and coded by the MPEG2 method, a coded stream with a reproduction speed of 1/2 can be obtained.

The multiplexed file 34 for frame-by-frame playback is
The original image is coded for frame-by-frame playback in the forward direction. For example, as shown in FIG. 9, input frames (f0, f6, f1) thinned out at regular intervals as shown in FIG.
2,... Are switched by several frame periods (in the figure, three frame periods).
It can be obtained by inputting from R, and predictively encoding it by the MPEG2 system.

FIG. 10 shows a state of the reproduction control process accompanied by switching of the multiplex files 31, 32, 33, and 34.
In FIG. 10, the client terminal is started at a constant time (for example, 10 seconds) in real time from the start of moving image transmission using the multiplexed file 31 for standard reproduction temporally encoded in the forward direction. User of slow playback command,
It is assumed that a frame-by-frame playback command and a standard playback command are input.

As shown in the figure, the multiplexed file 31 when the slow playback command is input from the client terminal.
If the playback time on the time axis of the moving image is “30”, the multiplexed file 33 for slow playback is skipped to a position corresponding to the playback time “30”, and then the playback time “30” The transmission of the coded stream using the multiplexed file 33 for slow reproduction is started from the I picture corresponding to. Then, after 10 seconds, a frame advance playback command is input. At this point, the multiplexed file 33
Is "45" on the time axis of the moving image. This is because the change speed of the reproduction time on the time axis of the moving image of the slow reproduction multiplex file 33 is １ ／ of that of the standard reproduction multiplex file 31.

The multiplexed file 34 for frame-by-frame playback is skipped to the position corresponding to the playback time "45",
From the I picture corresponding to the reproduction time “45”, transmission of the encoded stream using the multiplexed file for frame-by-frame reproduction is started. The reproduction time on the multiplexed file for frame-by-frame reproduction is advanced quickly, and when the standard reproduction command is input, the reproduction time is, for example, "135" as shown in the figure. In this case, the multiplexed file 31 for standard reproduction is skipped to the position corresponding to the reproduction time “135”, and then the multiplexed file 31 for standard reproduction is used from the I picture corresponding to the reproduction time “135”. Transmission of the encoded stream is started.

As described above, in the configuration of FIG. 7, in response to the reproduction mode designation command from the client terminal,
The multiplexed file used for moving image transmission is switched.

Next, the procedure of the moving image transmission control process by the moving image transmission server 13 of FIG. 7 will be described with reference to the flowchart of FIG. When the playback mode designation command is not input from the client terminal 10-1 (NO in step S201), the moving image transmission server 13 performs standard playback multiplexing corresponding to the content selected by the client terminal 10-1 as usual. The moving image is transmitted using the conversion file 31 (step S202). Client terminal 1 during moving image transmission using multiplexed file 31
When a playback mode designation command is input from 0-1 (YES in step S201), the moving image transmission server 13
It is determined whether the playback mode designated by the playback mode designation command is a standard playback mode, a slow playback mode, a frame-by-frame playback mode, or a reverse playback mode (steps S203, S204).

In the standard reproduction mode, the moving image transmission processing using the multiplexed file 31 is continuously executed (step S202). Note that when the slide bar 20 is operated during the moving image transmission processing in step S202, FIG.
The file switching process based on the time information as described in is performed in the moving image transmission process of step S202.

If the playback mode specified by the playback mode designation command is the slow playback mode, the moving image transmission server 13 switches the multiplex file used for moving image transmission to the multiplex file 33 for slow playback, and The moving image transmission process using the slow reproduction multiplex file 33 is started (step S205). Similarly, if the frame-by-frame playback mode is designated, the moving image transmission process using the multiplexed file for frame-by-frame playback (step S206)
If the reverse playback mode is designated, the moving image transmission process using the multiplex file 32 for reverse playback (step S20)
7) is executed.

When the slide bar 20 is operated during the slow playback control processing of step S205 or during the step-by-step playback control processing of step S206, the file switching based on the time information is performed similarly to the case of the standard playback processing. The processing is executed.

FIG. 12 is a flowchart showing the procedure of the slow reproduction control process executed in step S205. The moving image transmission server 13 includes a client terminal 10-
If no time information is input from step 1 (step S3
(NO at 01), moving image transmission is performed using the multiplexed file 33 for slow reproduction (step S302). Client terminal 1 during moving image transmission using multiplexed file 33
When time information is input from 0-1 (step S301)
YES), the moving image transmission server 13 sets the current playback time (T) indicated by the playback time information corresponding to the currently transmitted picture included in the encoded stream of the multiplexed file 33 for slow playback, and The reproduction time (t) specified by the time information is compared to determine whether the reproduction time (t) specified by the time information is temporally earlier than the current reproduction time (T) (step). S303, S30
4).

The reproduction time (t) specified by the time information
Is temporally past the current reproduction time (T) (YES in step S304), the moving image transmission server 13
Is switched to the multiplexed file 32 for reverse reproduction by the multiplexed file changeover switch 41, and the moving image transmission using the multiplexed file 32 is started from the current reproduction time (T) (step S305). If the current playback time (T) specified by the playback time information corresponding to the currently transmitted picture included in the coded stream of the multiplexed file 32 matches the playback time (t) specified by the time information (step) (YES in S306), the moving image transmission server 13 switches again to the multiplexed file 33 for slow reproduction with the multiplexed file switch 41, and the current reproduction time (T = t).
, The moving image transmission using the multiplexed file 33 for slow reproduction is restarted (step S307).

On the other hand, if the playback time (t) specified by the time information is temporally ahead of the current playback time (T) (NO in step S304), the moving image transmission server 13 The multiplexed file 33 is forwarded (skipped) until the reproduction time (t) specified by the time information (step S308).

FIG. 13 is a flow chart showing the procedure of the frame advance reproduction control process executed in step S206. The moving image transmission server 13 includes a client terminal 10-
If no time information is input from step 1 (step S4
(NO at 01), moving image transmission is performed using the multiplexed file for frame-by-frame playback (step S402). When time information is input from the client terminal 10-1 during moving image transmission using the multiplexed file for frame-by-frame playback (YES in step S401), the moving image transmission server 13
Is the current playback time (T) indicated by the playback time information corresponding to the currently transmitted picture included in the encoded stream of the frame-by-frame playback multiplexed file 34, and the playback time specified by the time information (T) to determine whether the playback time (t) specified by the time information is temporally earlier than the current playback time (T) (step S).
403, S404).

Playback time (t) specified by time information
Is temporally past the current reproduction time (T) (YES in step S404), the moving image transmission server 13
Is switched to the multiplexed file 32 for reverse reproduction by the multiplexed file changeover switch 41, and the moving image transmission using the multiplexed file 32 is started from the current reproduction time (T) (step S405). If the current playback time (T) specified by the playback time information corresponding to the currently transmitted picture included in the coded stream of the multiplexed file 32 matches the playback time (t) specified by the time information (step) (YES in S406), the moving image transmission server 13 switches to the multiplexed file 34 for frame-by-frame playback again with the multiplexed file switch 41, and the current playback time (T =
The moving image transmission using the multiplexed file for frame-by-frame playback is restarted from t) (step S407).

On the other hand, if the playback time (t) specified by the time information is temporally ahead of the current playback time (T) (NO in step S404), the moving image transmission server 13 The multiplexed file 34 for frame-by-frame playback is advanced (skipped) until the playback time (t) specified by the time information (step S408).

In this embodiment, in the case of high-speed reproduction and high-speed reverse reproduction, only the I picture is read from the standard reproduction multiplex file 31 and the reverse reproduction multiplex file 32 and transmitted. For each of the playback and the high-speed reverse playback mode, an encoded file dedicated to the playback mode is prepared in advance, and when the high-speed playback and the high-speed reverse playback are requested from the client terminal,
Moving image transmission may be performed using these dedicated encoded files.

Although the present embodiment has been described on the assumption that the network is the Internet, the present invention is not limited to this. In the present embodiment, the number of client terminals is three and the number of servers is one, but the number of client terminals and the number of servers are not limited to these. Further, the present invention can be applied to a moving image transmission system such as a video-on-demand system.

[0068]

As described above, according to the present invention,
By switching the file used for moving image transmission from an encoded file encoded for standard playback to an encoded file encoded for reverse playback, the client terminal uses a backward direction to the past position specified by the user. You can return the video while checking the video. In addition, by preparing encoded files for special playback such as reverse playback, slow playback, and frame-by-frame playback individually for each special playback mode, various special playbacks such as reverse playback, slow playback, and frame-by-frame playback can be performed on the server side. It can be easily realized only with the function.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of a moving image transmission system according to an embodiment of the present invention.

FIG. 2 is an exemplary view for explaining the structure of a standard reproduction multiplex file and a reverse reproduction multiplex file used in the embodiment;

FIG. 3 is an exemplary block diagram showing a functional configuration of a software viewer executed by a client terminal used in the embodiment;

FIG. 4 is an exemplary block diagram showing the internal configuration of a server used in the embodiment.

FIG. 5 is an exemplary view showing a state of a reverse reproduction process in the embodiment.

FIG. 6 is an exemplary flowchart illustrating the procedure of a moving image transmission control process in the embodiment.

FIG. 7 is an exemplary block diagram showing another configuration example of the server used in the embodiment;

FIG. 8 is a view for explaining a structure of a slow reproduction file prepared in the server of FIG. 7;

FIG. 9 is a view for explaining the structure of a frame-forward playback file prepared in the server of FIG. 7;

FIG. 10 is a view showing a state of a reproduction process when the server of FIG. 7 is used.

FIG. 11 is an exemplary flowchart illustrating the procedure of a moving image transmission control process executed by the server in FIG. 7;

FIG. 12 is a flowchart illustrating a procedure of a slow reproduction control process executed in the moving image transmission control process of FIG. 11;

13 is a flowchart for explaining a procedure of a frame-advance playback control process executed in the moving image transmission control process of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Network 2 ... GSTN 3 ... ISDN 4 ... PHS network 10-1 to 10-3 ... Client terminal 11 ... Gateway 12 ... Router 13 ... Moving picture transmission server 20 ... Slide bar (arranged on GUI) 21 ... Input buffer 22 ... Demultiplexing unit 23 ... Image decoding unit 24 ... Audio decoding unit 25 ... Image buffer 26 ... Audio buffer 27 ... Display (on terminal) 28 ... Speaker (on terminal) 29 ... Control unit (detection of time information, etc.) 30 ... Command Button (arranged on the GUI) 31: Multiplexed file (for standard playback) 32: Multiplexed file (for reverse playback) 33: Multiplexed file (for slow playback) 34: Multiplexed file (for frame-forward playback) 41 ... Multiplex file switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 7/18 H04N 7/137 Z F-term (Reference) 5C053 FA22 FA23 FA28 GB06 GB08 GB11 GB38 HA22 HA23 HA24 HA25 HA40 JA22 KA08 LA06 LA11 LA14 5C054 DA09 EA03 EG06 EG10 GA01 HA17 5C059 LB07 MA00 PP05 PP06 PP07 RB01 RC04 SS09 SS17 SS18 SS30 5C064 BA01 BA07 BC04 BC10 BC18 BC25 BD02 BD08

Claims (14)

[Claims] A moving picture transmission server for accumulating moving pictures and transmitting the stored moving pictures to a client terminal, wherein a standard reproduction signal obtained by temporally encoding the moving pictures in a forward direction is provided. A first encoded file, a second encoded file for reverse reproduction obtained by temporally encoding the moving image in the reverse direction, and the first and second encoded files. Moving image transmission control means for selectively transmitting a moving image to the client terminal, wherein, in response to a request from the client terminal, an encoded file used for moving image transmission is transmitted to the first terminal.
Moving image transmission control means for switching between the encoded file and the second encoded file. 2. The moving image transmission control means, during a moving image transmission period using the first encoded file, a time that is temporally past a current reproduction time on a time axis of the moving image. Means for switching an encoded file used for the moving image transmission from the first encoded file to the second encoded file when time information indicating the moving image is input from the client terminal; The moving image transmission using the second encoded file is performed until the reproduction time on the time axis of the second encoded file returns to the past time specified by the time information. Transmission server. 3. The moving image transmission control means uses the second encoded file until a reproduction time on the time axis of the moving image returns to a past time specified by the time information. When executing, further comprising means for switching the encoded file used for moving image transmission from the second encoded file to the first encoded file, from the past time specified by the time information The moving image transmission server according to claim 2, wherein the moving image transmission using the first encoded file is restarted. 4. The first coded file is composed of a coded stream in which intra-frame coded pictures are inserted at regular intervals, and the moving image transmission control unit performs a high-speed reproduction of the moving image. 2. The moving picture transmission server according to claim 1, further comprising means for transmitting only intra-frame coded pictures in the coded stream of the first coded file. 5. The second coded file is composed of a coded stream into which intra-frame coded pictures are inserted at a fixed period, and the moving image transmission control unit performs high-speed reverse reproduction of the moving image. 2. The moving picture transmission server according to claim 1, further comprising: means for transmitting only intra-frame coded pictures in the coded stream of the second coded file. 6. A slow reproduction encoded file obtained by encoding the moving image for slow reproduction, wherein the moving image transmission control means responds to a slow reproduction request from the client terminal.
2. The moving image transmission server according to claim 1, further comprising means for switching an encoded file used for moving image transmission to the encoded file for slow reproduction. 7. A frame-by-frame playback reproduction coded file obtained by encoding the video for frame-by-frame playback, wherein the video transmission control means, in response to a frame-by-frame playback request from the client terminal, 2. The moving image transmission server according to claim 1, further comprising means for switching an encoded file used for moving image transmission to the encoded file for frame advance reproduction. 8. A moving image transmission server for storing moving images and transmitting the stored moving images to a client terminal, comprising: a standard reproduction encoded file obtained by encoding the moving images for standard reproduction; A plurality of encoded files for special reproduction obtained by encoding moving images for a plurality of special reproductions different from each other, and according to a reproduction mode designated by the client terminal, the encoded file for standard reproduction and the plurality of Means for selecting an encoded file to be used for moving image transmission from among the encoded files for trick play, and transmitting the moving image to the client terminal using the selected encoded file. Moving image transmission server. 9. A moving image transmission system including a server that stores moving images and a client terminal that receives and displays moving images from the server, wherein the server temporally encodes the moving images in a forward direction. A first encoded file for standard reproduction obtained by the above, a second encoded file for reverse reproduction obtained by encoding the moving image in a temporally reverse direction, Moving image transmission control means for selectively transmitting a moving image to the client terminal by using a second encoded file, wherein the encoded file used for moving image transmission in response to a request from the client terminal The first
Moving image transmission control means for switching between the encoded file and the second encoded file. 10. A moving image transmission system including a server that stores moving images and a client terminal that receives and displays moving images from the server, wherein the server is a standard that encodes moving images for standard reproduction. An encoded file for reproduction, a plurality of encoded files for special reproduction obtained by encoding the moving images for a plurality of different special reproductions, and the standard reproduction according to a reproduction mode designated by the client terminal. Means for selecting an encoded file to be used for moving image transmission from among the encoded file for encoding and the plurality of encoded files for special reproduction, and transmitting a moving image to the client terminal using the selected encoded file. A moving image transmission system comprising: 11. A moving image transmission control method for transmitting a moving image stored in a server to a client terminal, the server comprising: a standard playback device for encoding a moving image in a forward direction in time; And a second encoded file for reverse reproduction obtained by temporally encoding the moving image in the reverse direction, and a request from the client terminal. And selecting an encoded file to be used for moving image transmission from the first and second encoded files, and transmitting the moving image from the server to the client terminal using the selected encoded file. A moving image transmission control method. 12. During a moving image transmission period using the first encoded file, the client terminal stores time information indicating a time earlier than a current reproduction time on a time axis of the moving image. When input from the, the encoded file used for the video transmission is switched from the first encoded file to the second encoded file, the reproduction time on the time axis of the video is the time information 12. The moving image transmission control method according to claim 11, wherein the moving image transmission using the second encoded file is performed until the specified past time is returned. 13. The second time until the reproduction time on the time axis of the moving image returns to the past time specified by the time information.
When moving image transmission using the encoded file of
The encoding file used for moving image transmission is switched from the second encoding file to the first encoding file, and a moving image using the first encoding file from a past time specified by the time information The moving image transmission control method according to claim 12, wherein the image transmission is restarted. 14. A moving image transmission control method for transmitting moving images stored in a server to a client terminal, the server comprising: a standard reproduction encoded file obtained by encoding a moving image for standard reproduction; A plurality of encoded files for special reproduction obtained by encoding moving images for a plurality of different special reproductions are provided, and the standard reproduction encoding is performed according to a reproduction mode specified by the client terminal. Selecting an encoded file to be used for transmitting a moving image from a file and a plurality of encoded files for special reproduction, and transmitting the moving image from the server to the client terminal using the selected encoded file. Characteristic moving image transmission control method.