JP2000209555A - Moving picture reproduction terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a picture from moving picture data at a rate corresponding to a channel rate even from a terminal where the required channel rate cannot be secured with respect to a moving picture reproduction terminal that is connected with a channel at a low transfer rate to a video server storing moving picture data coded at a pre-designated bit rate. SOLUTION: The moving picture reproduction terminal is provided with a display device 12 and a moving picture reproduction controller 10. The moving picture reproduction controller 10 is provided with a reproduction control section 100 that uses a frame calculation section 101 to obtain a start frame and an end frame for each reproduction cycle by using a frame compression rate corresponding to a transfer rate of a channel of the terminal with respect to a bit rate of coded moving picture data and a reproduction cycle and that conducts control of adding the obtained frame information to the moving picture data and requesting reproduction of the resulting moving picture data to a video server 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture reproducing terminal apparatus which receives, reproduces and displays coded digital moving picture data provided through a network.

[0002] MP as a digital encoding method for moving images
International standards have been established in the EG1 or MPEG2 standards. In addition, technology for real-time reproduction via a network has been established, and commercialization has been made. Also, MPEG2
Has a function of spatio-temporal scalability, and there is an encoding device that enables encoding by specifying a specific bit rate. However, a video playback terminal that receives encoded moving images is The bit rate of a moving image to be reproduced is restricted by the available line speed.

[0003]

2. Description of the Related Art In a service for providing a conventional video signal such as VOD (Video On Demand), a moving picture expert group 2 (MPEG2) which is a standard system of a high efficiency code is used.
According to such encoding, high-rate compression is realized using an inter-frame predictive encoding technique, and the data is efficiently stored in a database.

This MPEG2 is based on MPEG1 based on a combination of Discrete Cosine Transform (DCT) and motion compensation prediction, and is an international standard for image compression that realizes higher resolution and higher functionality. From John to High Definition Television (HDTV:
High Definition Television).

[0005] The video data compressed by this encoding method can freely change the encoding speed by designating the total bit rate as a parameter at the time of encoding, and can be compressed according to the available network bandwidth. Can be realized.

If this function is used, and if the available network bandwidth is fixed, storing the encoded data assuming the bit rate, the user will be most naturally in the range of the available network. It is possible to reproduce a close moving image.

However, there are cases where a plurality of terminals are connected to the network, and the available line speeds are different for each terminal. For example, a terminal connected to a 64 Kbps line or a 10 Mb
Some terminals are connected to the PS line. Such a terminal is provided with an image reproducing device capable of reproducing an encoded image corresponding to each speed. In such a case, it is necessary to perform encoding according to the lowest available line speed among multiple terminals, or to prepare encoded data by specifying multiple bit rates according to the type of the line speed. was there.

Further, depending on the type of network, a fixed line speed is not always guaranteed. In this case, a moving picture encoded at a specific bit rate can be used or used depending on timing. Or not.

FIG. 8 shows the configuration of a conventional system for handling moving image data. In the figure, 50 is a terminal, 51 is a control program, 52 is a client system including a playback device, 53 is a display device provided with input means, 54 is a network, 55 is a device that holds a large number of video data and requests from the terminal 50. A video server 56 for transmitting video data in accordance with the video server 55 is video data held by the video server 55 in large numbers.

In this configuration, the client system 52 is driven by the control program 51 of the terminal 50 and the file name of the video data 56 is designated, thereby requesting the video server 55 to reproduce via the network 54. The video server 55 fetches the video data 56 of the title selected in accordance with this at a determined speed,
The transmitted video data is transmitted to the terminal 50 via the line of the network 54, and the terminal 50 decodes the encoded video data by the client system 52 and displays the decoded video data on the display device 53.
Play the video until the end of the video data. There are also client systems that provide functions such as pause, fast-forward to a specified position, and rewinding function. In order to realize these functions, an interface such as a playback command specifying a start / end position is also provided.

As described above, the video server 55 holds encoded video data suitable for a fixed-speed network line in advance, and sets a predetermined transmission speed (band) in response to a request from each terminal. It is configured to send video data to the terminal to be compatible.

[0012]

According to the above-mentioned conventional technique, when a server storing an image has only one moving image data which is coded in order to provide the maximum image quality, it is difficult to use this method. If the required line speed cannot be secured on the side of the image reproducing terminal receiving the moving image, the moving image cannot be received and reproduced.

The present invention is directed to a terminal which cannot secure a line speed required when only a moving image data encoded on the server side storing an image is provided so as to provide the maximum image quality. It is another object of the present invention to provide a moving image reproducing terminal device capable of reproducing an image from moving image data with an image quality corresponding to the line speed.

[0014]

FIG. 1 is a diagram showing the principle configuration of the present invention. In the figure, 1 is a moving image reproducing terminal device, 10
Denotes a moving image reproduction control device, 11 denotes a reproduction device having a function of receiving image data from a video server, decoding image data under the control of the moving image reproduction control device 10 and displaying the image data on the input / display unit 12, An input / display unit representing a display device or the like having means; 13 is a start-up processing unit for performing processing such as setting of initial values; 14 is a timer; 20 is a bit for realizing moving image data to realize a preset high image quality Encoding apparatus for encoding at a rate, 21 is encoding apparatus 2
A video server 3 that holds a large number of moving image data encoded by 0 and transmits the moving image data in response to a request from a terminal is a network. Also, 100 in the moving image reproduction control device 10 is a reproduction control unit, 101 is a frame calculation unit, and 102 is a memory.

A moving picture is coded by a coding apparatus 20 corresponding to a specific speed suitable for a line having a relatively high transmission rate and stored in a video server 21. 3 to access the video server 21. In this example, it is assumed that the moving image reproduction terminal device 1 is connected to the network 3 by a low-speed line, and the reproduction control unit 10
0 is the number of frames per second of the fixed-speed video data output from the video server 21 to the memory 102 at the time of startup, and adapts the video data from the video server 21 to the line speed of the moving image reproduction terminal device 1. (Reduce data volume and sacrifice image quality to maintain real-time speed)
For this purpose, parameters such as a frame reduction rate and a reproduction cycle are set in the memory 102 from the activation processing unit (control program) 13 of the moving image reproduction terminal device 1.

When there is an open (opening) request specifying a title from the moving picture reproducing terminal device 1 to the video server 21 via the network 3, the corresponding video data is opened and the video data requested as a sense signal is opened. Is transmitted from the video server 21 to the moving image reproducing terminal 1 via the network 3 as in the conventional case, and the reproduction control unit 100 stores this in the memory 102. Also, the frame calculation unit 1
In step 01, the numbers of the start frame and the end frame in the first transmission cycle are calculated by using the frame reduction rate, the frame cycle, and the like set in the memory 102. The calculated frame number is transmitted from the network 3 to the video server 2
1 is added to a reproduction command (PLAY) as frame information for requesting transmission, and the timer 14 sets a reproduction cycle stored in the memory 102. Upon receiving the request, the video server 21 reads out the video data from the specified start frame to the end frame of the video data of the previously specified title, and
Send to.

The video data of the plurality of frames is received by the reproducing apparatus 11, decoded, and displayed on the input / display unit 12. After that, when the playback cycle ends, the timer 14 sets the playback control unit 100 to add the number of frames corresponding to the playback cycle to the previous start frame (that is, the frame to be played back after the playback cycle time has elapsed) as the first frame. Then, a frame position excluding the frame to be reduced by the reduction rate from the last frame in the reproduction cycle is designated as an end frame, and a reproduction instruction is issued to the video server 21 via the network 3. As described above, the reproduction frames are transmitted in order (a predetermined number of reduced frames and a predetermined number of reproduction frames alternately occur), and when the last frame is reached, the moving image reproduction terminal device 1 issues a close command. Send. Video server 21
Receives this, closes the video data being reproduced.

[0018] In this way, even if a terminal connected to a narrow-band line can re-encode coded moving image data requiring a wide band in order to provide the maximum image quality, even if it sacrifice a little smooth operation. It is possible to reproduce without conversion.

According to the present invention, the number of frames to be displayed is made closer to the number of frames at the time of encoding, or the period of reproduction is shortened, and the number of frames reduced per period is reduced, so that the number of frames to be displayed is reduced. It is possible to reproduce a video close to a natural moving image.

[0020]

FIG. 2 shows the configuration of an embodiment of a moving picture reproducing terminal device.

In FIG. 2, reference numerals 10 to 14 denote constituent elements constituting a moving picture reproducing terminal device, each symbol is the same as that of the same reference numeral in FIG. 1, 10 is a moving image reproducing control device, and 11 is A playback device, 12 is a monitor device having input devices such as a keyboard and a mouse (corresponding to the input / display unit in FIG. 1), 13 is a control program (startup process), and 14 is a timer.

In the moving image reproduction control device 10,
Reference numeral 102 corresponds to each unit of the same reference numeral in FIG. 1, 100 is a reproduction control unit, 101 is a frame calculation unit that calculates a reproduction start frame and an end frame, and 102 is a memory. In FIG. 1, elements 103 and 104, which are not shown, are added, 103 is a timer starting unit, and 104 is a parameter receiving unit. Also, 102a to 102a in the memory 102
102e represents a storage area of data to be stored, and 102a
Is the total number of frames of moving image data, 102b is the start frame, 102c is the remaining frame rate, 102d is the reproduction cycle,
Reference numeral 102e denotes each storage area of the number of frames per second. A known interface such as an MCI (Media Control Interface) can be used as an interface between the playback device 11 and the playback control unit 100. The moving image reproduction control device 10 is connected to a network line,
(Multimedia Transfer Protocol).

The processing flow in each unit according to the configuration of FIG. 2 will be described below with reference to FIGS.

The moving image reproduction control device 10 shown in FIG. 2 is started by a start process 13 in a control program of a personal computer or the like, and the parameter receiving unit 104 operates first.

FIG. 3 is a processing flow of the parameter receiving unit, in which the frame reduction rate and the moving image reproduction cycle corresponding to the speed (band) of the line to which the moving image reproducing terminal shown in FIG. Control program 13
To the parameter receiving unit 1 of the moving image reproduction control device 10
04. When the operation is started, the parameter accepting unit 104 subtracts the received frame reduction rate from “1” (1−frame reduction rate = frame remaining rate) and stores it in the frame remaining rate saving area 102 c in the memory 102. (S1 in FIG. 3), the reproduction cycle is stored in the reproduction cycle storage area 102d of the memory 102 (S2). Next, it is determined whether or not the number of frames per second has been designated from the control program 13 (S3 in FIG. 3). If not, a predetermined value is adopted (a default value is adopted in a standard NTSC television). 97 (frames / second) are stored in the frame 102 per second storage area 102 e of the memory 102. When the number of frames per second is specified, the specified numerical value is stored in the frame number per second storage area 102e.

Instead of receiving these parameters from the control program 13 as startup parameters, an inquiry screen is displayed on the monitor (12 in FIG. 2), and the frame reduction rate and the reproduction cycle It can be changed to receive the file name of the moving image data and the like.

Next, the parameter receiving unit 104 sets “1” in the storage area of the start frame, and
To execute a control such as an instruction to the playback device (11 in FIG. 2), opening of data to the video server (21 in FIG. 1), and an instruction to play back by specifying a frame (S in FIG. 3).
7). The contents of the processing of the reproduction control unit 100 are shown in FIG. 4 described later.

The parameter receiving unit 104 activates the reproduction control unit 100 to perform processing such as an instruction to open moving image data, and then, starts a timer activation unit (1 in FIG. 2).
03) (S8 in FIG. 3), further activates the frame calculation unit (S9), and ends after each processing. The processing contents of the timer activation unit and the processing contents of the frame calculation unit are respectively shown in FIGS.

FIG. 4 is a processing flow of the reproduction control unit (100 in FIG. 2). Note that the reproduction control unit performs not only the instruction to open the moving image data in step S7 of the parameter receiving unit in FIG. 3 but also various instructions from the control program (13 in FIG. 2) (user input or application program). Close and playback caused by PLAY (PLAY)
And the like).

When the playback control unit is started, it is first determined whether the instruction is an open instruction (command) including the title (name) of the moving image data (S1 in FIG. 4). A title is specified to 21) in FIG. 1 to instruct open processing (S2 in FIG. 4). In response to this, the video server opens the video data of the requested title and sends back information on the total number of frames to the video playback terminal device. When this is received by the reproduction control unit, it is set in the storage area 102a of the total number of frames in the memory 102 (S3). If the instruction is not an open instruction, it is determined whether the instruction is a close instruction (occurs after the end of the frame) (S4 in FIG. 4). If the instruction is a close instruction, the video server closes the moving image data previously opened. Instruct (S5). If it is determined in step S4 that the instruction is not a close instruction, it is determined whether the instruction is a reproduction (PLAY) instruction (S5 in FIG. 4). If the instruction is reproduction, a frame request is made to the video server (at this time, described later). The playback device (1 in FIG. 2) is added together with the frame information of the start frame and end frame to be added.
For 1), an instruction to decode the moving image data and perform the reproduction process is generated (S7 in FIG. 4).

FIG. 5 is a processing flow of the timer starting unit. When the timer activation unit (103 in FIG. 2) starts operation, it determines whether or not cancellation processing has been instructed (S103 in FIG. 5).
1) When the canceling process is instructed, the timer regular start is canceled (S2 in FIG. 5). When the canceling process is not cancelled, the set value of the reproduction cycle storage area (102d in FIG. 2) is set as the timer start interval (FIG. 2). 5 S3), a timer activation interval is set for the timer (14 in FIG. 2), and a request is made to activate the frame calculation unit (101 in FIG. 2) at the activation interval (S4 in FIG. 5).

The frame calculation unit (101 in FIG. 2) is first activated once by the parameter reception unit 104,
It is started by the timer 14 periodically.

FIG. 6 shows a processing flow of the frame calculation section. When the processing is started, each value of the storage area 102e of the number of frames per second in the memory 102, the storage area 102d of the reproduction cycle, and the storage area 102c of the remaining frame rate is taken out. And multiply (multiply), and save the start frame storage area 1
The end frame is obtained by adding the value stored in 02b and subtracting 1 from the result (S in FIG. 6).
1). The end frame is for determining how many frames (final frame) should be transmitted when the frame is reduced from the start frame (first one frame) by the frame reduction rate with respect to the time of the first reproduction cycle. Next, it is determined whether or not the obtained final frame has exceeded the value of the storage area 102a of the total number of frames of the moving image data (S2 in FIG. 6). If it exceeds, the value of the end frame is replaced with the value of the total frame number storage area 102a of the moving image data (S3 in FIG. 6), and S
Move to 4. If not exceeded, the frame calculation unit 101 instructs the reproduction control unit (100 in FIG. 2) to reproduce from the frame having the value of the start frame storage area 102b to the end frame (S4 in FIG. 6). As a result, a playback (PLAY) command (command) is issued to the video server.
Is transmitted with the start frame value and the end frame value added.

The video server (21 in FIG. 1) receiving this extracts the data of the number of frames from the start frame value to the end frame value added to the reproduction command in the requested moving image data, The encoded data is transmitted to the video playback terminal device within the playback cycle, and the encoded data is decoded by the playback device 11 shown in FIG.

Subsequently, the result obtained by multiplying the number of frames per second stored in the storage areas 102e and 102d of the memory 102 by the reproduction cycle and adding the value of the start frame (storage area 102b) is stored as a new start frame. Area 10
2b (S5 in FIG. 6). The updated value of the start frame becomes the start frame value when a reproduction request for the next frame is made.

Next, it is determined whether the updated start frame value matches or exceeds the total number of frames of the moving image data stored in the storage area 102a (S6 in FIG. 6). The activation unit (103 in FIG. 2) is instructed to cancel the regular activation (S7 in FIG. 6),
The reproduction control unit (100 in FIG. 2) is instructed to request the close processing of the moving image data (S8). Thus, the moving image reproduction control device (10 in FIG. 2) ends the entire processing.

In step S6, if the updated start frame has not reached the total number of frames of the moving image data, the processing of this reproduction cycle is terminated, and it is waited for the timer 14 to restart. When started at the next reproduction cycle, the processing from step S1 in FIG.
Assuming that the next frame after the frame (including the reduced frame) completed in the previous reproduction cycle is the start frame, FIG.
Are repeated until the reproduction of the entire range of the moving image data is completed.

FIG. 7 shows an example of moving picture reproduction according to the present invention. FIG. Is a reproduction cycle of 1 second, 30 frames / second,
Total bit rate = 3Mbps (including transmission loss)
This is a case where the moving image data encoded by MPEG2 is reproduced without passing through a line (or a case where the moving image data is reproduced via a network having a transmission band of 3 Mbps or more). In this case, all the frames from the left frame 1 are continuously reproduced in each reproduction cycle, and the data amount is 3 M bits per second, so that 3M / 30 = 0.
1M = 100K bits of information amount (actually, the data amount per frame varies by orders of magnitude depending on the picture type).

FIG. According to the present invention. 3 shows a frame that is reproduced when the data is reproduced with a reproduction cycle of 1 second and a reduction rate of 2/3 = 0.666. In this case, B. As shown by a solid line, only 10 frames from frame 1 to frame 10 are reproduced in the first reproduction cycle (0 to 1 second), frames 11 to 30 are skipped, and the next reproduction cycle (1 second to 2 seconds) is performed. ), The frames 31 to 40 are reproduced, the frames 41 to 60 are skipped, and the frames 61 to 60 are reproduced in the next reproduction cycle (2 to 3 seconds).
The frame 70 is reproduced, and the frames 71 to 90 are reproduced.
Are skipped, and so on until the total number of frames of the moving image data is reached. In this example, 2 /
3, the amount of transmission data is reduced, and reproduction via a network having only one third of the band becomes possible.

[0040]

According to the present invention, a video server that stores only moving image data coded assuming the provision of the maximum image quality is provided to a terminal that cannot secure a required line speed. Even at this speed, an image can be reproduced from the moving image data at a speed corresponding to the line speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram illustrating a configuration of an embodiment of a moving image reproduction terminal device.

FIG. 3 is a diagram showing a processing flow of a parameter receiving unit.

FIG. 4 is a diagram showing a processing flow of a reproduction control unit (100 in FIG. 2).

FIG. 5 is a diagram illustrating a processing flow of a timer activation unit.

FIG. 6 is a diagram showing a processing flow of a frame calculation unit.

FIG. 7 is a diagram showing an example of moving image reproduction according to the present invention.

FIG. 8 is a diagram showing a configuration of a conventional system for handling moving image data.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 moving image playback terminal device 10 moving image playback control device 100 playback control unit 101 frame calculation unit 102 memory 11 playback device 12 input / display unit 13 start-up processing unit 14 timer 20 encoding device 21 video server 3 network (network)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Kuroda 2-31-19 Shiba, Minato-ku, Tokyo Inside the Banzai Building 9F Communication and Broadcasting Corporation (72) Shinichiro Nomura 2-31-19 Shiba, Minato-ku, Tokyo No. Banzai Building 9F F-term in Communications and Broadcasting Corporation (reference) 5C053 FA28 GB17 GB38 HA33 HA40 LA11 5C059 KK34 LB07 PP04 RA01 RC22 SS09 TA07 TB04 TC37 TD14 UA05 5K030 HB02 JT04 KA19

Claims (3)

[Claims] 1. A video server, which holds moving image data encoded at a bit rate specified in advance and performs an operation in response to an instruction from a terminal such as opening, reproducing, closing, etc., via a network. A video playback terminal device connected by a line lower than the bit rate of the video, the video playback terminal device includes a playback device, a display device, and a video playback control device, and the video playback control device includes the codec. A frame calculation unit for obtaining a start frame and an end frame for each reproduction cycle by using a frame reduction rate corresponding to the line speed of the terminal with respect to the bit rate of the converted moving image data, and a reproduction cycle. A video playback terminal device for controlling the video server to request the video server to reproduce video data by adding the frame information. . 2. The moving image reproduction control device according to claim 1, wherein the moving image reproduction control device holds information on the total number of frames of the moving image notified when the moving image is accessed and the moving image is designated.
Wherein the frame calculation unit calculates a start frame and an end frame for each reproduction cycle based on an elapsed time from a previous reproduction, and controls a reproduction request until the total number of frames is reached. Playback terminal device. 3. The moving picture according to claim 1, wherein the frame calculation unit is started by a timer, and the timer generates an output periodically when the reproduction cycle is set. Image reproduction terminal device.