JP2004080145A - Video server system and video playback method thereof - Google Patents

Abstract

A video data system that reduces the load on a host server and has excellent system expandability.
A host server transmits recording information of a video content to a user terminal in response to a reproduction request for the video content from the user terminal. A request for transfer of each video stream data is made to a plurality of distributed recording servers 102 to 104 which divide the content into a plurality of video stream data and record the divided video data. The data is transferred to the user terminal 105, and the user terminal 105 reconstructs each piece of video stream data transferred from each of the distributed recording servers 102 to 104 into one piece of video stream data and reproduces it as video content.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a video server system that continuously supplies video content to a plurality of user terminals, and in particular, stores one video stream data in a plurality of data storage devices in a distributed manner, and requests data from the user terminals. At times, the present invention relates to a video server system in which a plurality of data storage devices operate in synchronization and supply one video stream data.
[0002]
[Prior art]
First, the configuration and operation of a conventional video server will be described. FIG. 10 is a diagram showing a configuration of a conventional video server. In FIG. 10, reference numeral 1001 denotes a user terminal management unit which receives a request to play or stop a video stream from a user terminal, or a special playback request, and sets the information in a user terminal management table described later. To give operation instructions and the like. Reference numeral 1002 denotes a user terminal management table, which holds which user terminal is requesting what kind of operation for which video content. Reference numeral 1003 denotes a scheduler, which has a function of determining at what timing video data is to be read and transmitted to the user terminal in accordance with an instruction from the user terminal management unit 1001, and issuing an instruction to a magnetic disk storage device and a transmission buffer, which will be described later. Having.
[0003]
Reference numeral 1004 denotes a magnetic disk storage device, which holds reference information as to which address in the magnetic disk storage device group the stream data of which video content is recorded, and is referred to by the above-described scheduler 1003. Reference numeral 1005 denotes a group of magnetic disk storage devices, which hold a large number of video stream data. It should be noted that simultaneous distribution to a larger number of user terminals is realized by being configured with a plurality of magnetic disk storage devices. Reference numeral 1006 denotes a transmission buffer, which has a function of temporarily holding video stream data read in accordance with an instruction from the scheduler 1003. The held video stream data is transmitted to the user terminal according to an instruction from the scheduler 1003. A communication I / F unit 1007 is used for transmitting / receiving control data to / from the user terminal and transmitting video stream data to the user terminal.
[0004]
In the video server described above, the scheduler sends out the stream data of the video content specified by the user terminal according to the operation specified by the user, and the user terminal reproduces the received stream data.
[0005]
[Problems to be solved by the invention]
However, the video server system including the above-described conventional video server has the following problems.
[0006]
First, as the number of user terminals increases, the load on the video server also increases, and there is a possibility that stable video distribution cannot be performed. In particular, the load on the scheduler 1003 is a major problem. In addition, such an increase in load complicates calculations such as when to transmit video stream data when a special reproduction request from a user terminal, for example, a request for fast-forward reproduction or the like is made. May also occur.
[0007]
Further, in the configuration of the conventional video server, simultaneous distribution to a larger number of user terminals can be realized by increasing the number of magnetic disk storage devices in the magnetic disk storage device group and the number of interfaces of the communication I / F unit. However, the number of expansions is limited. Therefore, in order to realize simultaneous distribution to a larger number of user terminals, it is necessary to install a plurality of video servers themselves. In this case, in order to be able to provide a service even when all user terminals request the same content, it is necessary to copy the same video content to all video servers, and increase the number of video servers. However, there is a problem that the number of video contents cannot be increased.
[0008]
SUMMARY An advantage of some aspects of the invention is to provide a video server system that reduces the load on an upper server and has excellent system expandability.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an upper server that manages recording information of video content, a plurality of distributed recording servers that divides the video content into a plurality of video stream data and records the video content, A video server system connected to a user terminal to be reproduced via a network, wherein the upper server transmits recording information of the video content to the user terminal in response to a reproduction request for the video content from the user terminal; Means, transfer request means for the user terminal to request transfer of video stream data to each distributed recording server based on the recording information of the video content, and each distributed recording server synchronized with the communication means by the communication means, Transfer means for transferring video stream data to the And having a reproducing means for reproducing the video content based on the video stream data transferred from the server.
[0010]
Also, the present invention provides an upper server that manages recording information of video content, a plurality of distributed recording servers that divide the video content into a plurality of video stream data and record the same, and a user terminal that reproduces the video content. A video playback method for a video server system connected via a network, wherein the host server transmits recording information of the video content to the user terminal in response to a playback request for the video content from a user terminal, Based on the recording information of the content, the user terminal makes a transfer request for video stream data to each distributed recording server, and each distributed recording server transfers video stream data to the user terminal in synchronization by communication means, The user terminal transmits the video data based on each video stream data transferred from each distributed recording server. There, characterized in that it reproduces the video content.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a diagram illustrating a configuration of a video server system according to the present embodiment. An upper server 101 shown in FIG. 1 has a function of managing the entire video server system, and performs management of recording information of video content, management of user terminals, synchronization control of a distributed recording server, and the like. It is assumed that there is only one host server 101 on one video server system.
[0013]
Reference numerals 102 to 104 denote distributed recording servers which hold divided video stream data of a large number of video contents, and have a function of transmitting the video stream data at a predetermined timing in response to a request from a user terminal described later. In the example shown in FIG. 1, the number of distributed recording servers is three, but the present invention is not limited to this. Generally, as the number of distributed recording servers increases, the number of user terminals that can simultaneously deliver video can be increased.
[0014]
Reference numerals 105 to 108 denote user terminals, which select video contents held in the distributed recording servers 102 to 104 from the recorded information of the video contents held in the host server 101, perform operations such as reproduction, and browse the videos. Has functions. In the example shown in FIG. 1, the number of user terminals is four, but the number is not limited to this.
[0015]
Reference numeral 109 denotes a network that connects the above-described upper server 101, distributed recording servers 102 to 104, and user terminals 105 to 108. In the present embodiment, it is assumed that Ethernet (registered trademark) is used.
[0016]
Here, a configuration and a schematic function of the upper server 101 shown in FIG. 1 will be described.
[0017]
FIG. 2 is a diagram illustrating a configuration of the upper server 101 according to the present embodiment. In FIG. 2, reference numeral 201 denotes a distributed recording server management unit, which has a function of managing the state of all distributed recording servers on the present system and performing a communication described later in detail. A user terminal management unit 202 manages the states of all user terminals on the present system and has a function of performing communication, which will be described later in detail. Reference numeral 203 denotes a channel management unit which has a function of allocating and releasing a new channel from the user terminal management unit 202 and managing a channel allocation table described later.
[0018]
The term “channel” as used herein is a concept for each video stream when each video stream selected is distributed to a plurality of user terminals on the present video server system. Means that it has the ability to deliver up to 40 video streams to different user terminals at the same time. The video server system shown in FIG. 1 according to the present embodiment will be described below as supporting 12 channels.
[0019]
Reference numeral 204 denotes a channel assignment table, which holds information such as channel use / vacancy, assigned contents, and user terminals. Reference numeral 205 denotes a video stream recording information management unit. When a transfer of the video stream recording information corresponding to the browse content specified by the user is requested from the user terminal management unit 202, the video stream recording information management table 205 It has a function of providing the corresponding record information. Furthermore, when a video stream is newly registered, recording information of the video stream data is created and stored in a magnetic disk storage device described later, and the correspondence between the video stream data and the recording information is set in the video stream recording information management table. It has a function to do. This video stream recording information will be further described later.
[0020]
Reference numeral 206 denotes a video stream recording information management table, which holds correspondence between video contents and video stream recording information. Reference numeral 207 denotes a magnetic disk storage device, which is a so-called hard disk drive (HDD). In the present embodiment, it is used to hold video stream recording information.
[0021]
Reference numeral 208 denotes video stream recording information, which records, in order from the beginning to the end of the video stream, which video stream data corresponding to the recording information is divided and stored in which block of which magnetic storage device of which distributed recording server. It was done. In the present embodiment, it is assumed that the video stream data is divided into data units corresponding to 500 ms.
[0022]
Reference numeral 209 denotes a synchronous packet transmitting unit, which has a function of multicast-transmitting synchronous packets to all distributed recording servers at once at a fixed period so that each distributed recording server can operate in synchronization. In the present embodiment, it is assumed that the synchronization packet is transmitted every 500 ms corresponding to the division unit of the video stream data.
[0023]
Reference numeral 210 denotes a timer counter, which is used to obtain a period at which the synchronous packet transmitting unit 209 transmits a synchronous packet, and has a function of generating a timer interrupt every 500 ms in the present embodiment. Reference numeral 211 denotes a network protocol. In this embodiment, standard TCP / IP and Ethernet (registered trademark) are used. TCP is used to exchange control data with the distributed recording server and the user terminal. TCP that ensures communication reliability is used, and UDP is used as a higher-layer protocol for multicast transmission of synchronization packets. Furthermore, synchronization packets utilize IP multicast transmission.
[0024]
Next, each configuration of the distributed recording servers 102 to 104 shown in FIG. 1 and a schematic function thereof will be described.
[0025]
FIG. 3 is a diagram illustrating a configuration of the distributed recording server according to the present embodiment. In FIG. 3, reference numeral 301 denotes a channel control unit, which includes a reading scheduler and a video stream transmission unit, which will be described later, and has a function of transmitting corresponding video stream data in response to a video stream data transmission request from a user terminal. Reference numeral 302 denotes a read scheduler, which has a function of managing the timing and order of reading video stream data to be transmitted to the user terminal from a magnetic disk storage device described later. Reference numeral 303 denotes a video stream transmission unit, which has a function of transmitting video stream data to be transmitted to the user terminal in accordance with the channel timing assigned to the user terminal and further controlling the video stream data at a transfer rate.
[0026]
Reference numeral 304 denotes a channel assignment table, which is the same as the channel assignment table 204 created and managed by the host server 101. A magnetic disk storage device 305 is a so-called hard disk drive. The number of the magnetic disk storage devices 305 may be plural instead of one. The magnetic disk storage device 305 stores a large number of video stream data divided into a plurality of blocks. A transmission buffer 306 has a function of temporarily storing video stream data to be transmitted to the user terminal. The transmission buffer 306 is dynamically allocated / released according to the number of used channels.
[0027]
An upper server communication unit 307 has a communication function with the upper server 101, and particularly has an acquisition and setting function of a channel assignment table created by the upper server 101. A user terminal communication unit 308 has a function of communicating with the user terminal. In particular, it is responsible for sending and receiving control data such as a request for communication of video stream data from a user terminal. Reference numeral 309 denotes a synchronization packet receiving unit, which has a function of setting a timer counter, which will be described later, in accordance with the synchronization packet sent from the host server. Reference numeral 310 denotes a timer counter, which has a function of generating a timer interrupt at a cycle set by the synchronization packet receiving unit 309. This timer interrupt is used for synchronizing the timing of video stream transmission by the channel control unit 301 and the like.
[0028]
Reference numeral 311 denotes a network protocol, which is equivalent to the above-described upper server 101. Transmission / reception of control data with an upper-level server or a user terminal uses TCP that ensures communication reliability, and transmission of video stream data uses UDP as an upper-level protocol.
[0029]
Subsequently, each configuration of the user terminals 105 to 108 shown in FIG. 1 and their schematic functions will be described.
[0030]
FIG. 4 is a diagram illustrating a configuration of the user terminal according to the present embodiment. In FIG. 4, reference numeral 401 denotes a video stream reproducing unit, which mainly has a function of designating a reproduced video content and a reproducing method and reproducing the received video stream data. In particular, by referring to the video stream recording information acquired from the host server 101 and issuing an instruction to the transfer request scheduler, various reproductions (such as cueing and fast forward reproduction) can be performed. Reference numeral 402 denotes an upper server communication unit, which communicates with the upper server 101, and has a function of designating video content and acquiring video stream record information. Reference numeral 403 denotes video stream recording information, which is the same as one of the 208 managed by the magnetic disk storage device 207 of the host server 101 described above.
[0031]
Reference numeral 404 denotes a transfer request scheduler and a sequential number management unit, which has a function of issuing a video stream data transfer request instruction to each distributed recording server in accordance with the instruction from the video stream reproduction unit. At this time, in order to reconstruct the video stream data transferred from each distributed recording server and create one piece of video stream data, a sequential number is assigned and a transfer request is made to each distributed recording server. It also has a function of managing the transmission timing of the transfer request. Reference numeral 405 denotes a distributed recording server communication unit, which communicates with each distributed recording server, and particularly has a transfer request communication function from the transfer request scheduler described above.
[0032]
A reception buffer 406 has a function of temporarily holding video stream data transferred from each distributed recording server. This reception buffer is secured according to the number of distributed recording servers on the system. Reference numeral 407 denotes a video stream reconstructing unit which extracts video stream data temporarily stored in the reception buffer 406 in order of a sequential number at a constant period (500 ms in the present embodiment) and provides it to the video stream reproducing unit 401. It has a function to do. A timer counter 408 has a function of generating a timer interrupt at a constant period (500 ms in the present embodiment). This timer interrupt is used by the transfer request scheduler 404 and the video stream reconstruction unit 407.
[0033]
Reference numeral 409 denotes a network protocol, which is equivalent to the above-described upper server 101. Transmission / reception of control data with an upper-level server or a user terminal uses TCP that ensures communication reliability, and reception of video stream data uses UDP as an upper-level protocol.
[0034]
Next, a method of recording one piece of video stream data that is divided and recorded in a plurality of distributed recording servers according to the present embodiment will be described.
[0035]
The video stream data is divided into stream data every 500 ms, and is sequentially repeated from the distributed recording server 1 in the order of 2, 3 and recorded on each magnetic disk storage device. However, the first divided data of the stream does not necessarily have to be recorded in the distributed recording server 1, and may be recorded starting from any of 2 and 3. This recording information is associated with the video content as video stream recording information, and is stored in the host server 101.
[0036]
FIG. 5 is a diagram illustrating an example of recording information according to the present embodiment. In FIG. 5, reference numeral 501 denotes video stream recording information, which is an example of video content of 30 seconds (the number of blocks is 60) in this example. The video stream recording information is composed of a list of block information. As shown in FIG. 5, the block information includes a block number 502, a distributed recording server identification number 503, a recording disk identification number 504, a recording address 505, and a data length 506. The recording disk identification number 504 is used to identify a plurality of magnetic disk storage devices when one distributed recording server is connected. Also, by requesting each distributed recording server recorded in the video stream recording information every 500 ms to transfer the video stream data for the recording disk, recording address, and data length in the order of the block number of the block number 502, The corresponding video stream data is sequentially transmitted from the server, and normal reproduction of the video content can be performed.
[0037]
Next, the slots, system slots, and server slots used in the video server system will be described in detail.
[0038]
In the present embodiment, three distributed recording servers realize 12 channels. In other words, if a single distributed recording server can transmit up to four channels within 500 ms, the entire system (three distributed recording servers) can achieve up to twelve channels. Of course, each distributed recording server must transmit the channel so as not to overlap. In order to avoid such duplication, it is necessary to manage which channel each distributed recording server should transmit to in the entire system. Here, in order to realize 12 channels with three distributed recording servers, it is sufficient to divide the 12 channels into three groups (each of four channels). This group is called a "slot", and channels 1 to 4 are assigned to slot 1, channels 5 to 8 are assigned to slot 2, and channels 9 to 12 are assigned to slot 3.
[0039]
The “system slot” is a slot managed by the host server 101 and circulates in slots 1, 2, and 3 every 500 ms. Further, the “server slot” is a slot managed by each distributed recording server, and circulates through slots 1, 2, and 3 similarly to the above-described system slot. However, server slots in each distributed recording server must not overlap at the same time.
[0040]
FIG. 6 is a diagram showing the relationship between the system slot and the server slot of each distributed recording server in the present embodiment. According to the relationship shown in FIG. 6, each server slot can transmit the video stream data to the channel corresponding to the slot every 500 ms period, and the server channel of each server does not overlap. There is no duplication between distributed recording servers.
[0041]
Further, a timing synchronization process between the host server and each distributed server will be described with reference to a timing chart shown in FIG. This timing synchronization is specifically intended to synchronize the above-described slot switching timing in the entire system, and is always executed during operation of the system.
[0042]
As described above, the time corresponding to one slot of the video server system of the present embodiment is 500 ms corresponding to the unit time of the divided video stream data, and this is defined as the timing synchronization cycle. The synchronization packet 801 including the system slot number is multicast-transmitted from the host server 101 to each distributed recording server every 500 ms. Each distributed recording server that has received the synchronization packet 801 switches the server slot according to the relationship 601 shown in FIG. 6, and transmits data to the channel for which video stream data distribution is requested. 8, 802 indicates slot 1, 803 indicates slot 2, and 804 indicates slot 3.
[0043]
Next, processes performed by the host server 101, the distributed recording servers 102 to 104, and the user terminals 105 to 108, which are performed at an arbitrary timing in parallel with the timing synchronization process described above, will be described. First, the login / logout processing by the user terminal will be described.
[0044]
The upper server 101, for which a login request has been made from an arbitrary user terminal, first selects an appropriate free channel from all 12 channels in the channel management unit 203, performs allocation to the user terminal, and updates the channel allocation table 204. . Next, the distributed recording server management unit 201 notifies the contents of the updated channel allocation table to all the distributed recording servers 102 to 104. Further, the user terminal management unit 202 of the host server 101 notifies the user terminal of the assigned channel number. If there is no free channel, the channel assignment table is not updated, the busy state is notified to the user terminal, and login is not permitted. Here, it is assumed that channel 6 (belonging to slot 2) has been allocated.
[0045]
The user terminal to which the channel has been assigned obtains all the registered video contents from the host server 101 and specifies the video contents to be viewed. The list of video contents can be browsed using, for example, a Web browser, and the contents can be specified by a method of specifying the viewed video contents through the Web browser.
[0046]
In the host server 101 having received the content designation, the video stream recording information management unit 205 searches for the video stream recording information 208 corresponding to the video content, and the corresponding video stream recording information is stored in the user terminal management unit 202. Transmitted to the user terminal. Here, it is assumed that the video stream recording information 501 shown in FIG. 5 has been selected. On the other hand, the user terminal that has acquired the video stream recording information can perform reproduction based on the information.
[0047]
As for logout, the user terminal releases the video stream recording information and requests the upper server 101 to logout. Upon receiving this request, the host server 101 releases the channel allocated to the user terminal and updates the channel allocation table 204. Next, the distributed recording server management unit 201 notifies the distributed recording server management unit 201 of the contents of the updated channel allocation table 204 to all the distributed recording servers 102 to 104. Finally, the user terminal is notified that the logout process has been completed.
[0048]
Next, a normal reproduction process according to the present embodiment will be described with reference to FIGS. 4, 5, 7, and 9. FIG. First, the transfer request processing in the user terminal will be described.
[0049]
The video stream playback unit 401 of the user terminal instructs the transfer request scheduler 404 to perform normal playback from the beginning. The transfer request scheduler 404 that has received the instruction refers to the acquired video stream recording information 403 (as described in 501), and transmits a transfer request for the video stream data of block 1 (901). That is, a transfer request packet of video stream data having a data length of 400000 recorded at recording disk number 1 and recording address 100 is transmitted to the distributed recording server 2. FIG. 7 shows the transfer request packet format at that time. In FIG. 7, reference numerals 704 to 706 denote recording disk numbers, recording addresses, and data lengths. In addition, 702 denotes a channel number assigned to the user terminal, and 703 denotes a sequential number indicating the order of data transmission requests. Is stored as the transfer request packet 701. Similarly, every time a timer interrupt is received from the timer counter 408 every 500 ms, the data is transferred to each distributed recording server in the order of blocks 2, 3, 4, 5,... As indicated by 902 to 905 in FIG. The request packet 701 is transmitted while incrementing the sequential number 703.
[0050]
Next, the video stream data transfer processing in each distributed recording server will be described.
[0051]
As described above, the distributed recording server sequentially switches the slot state to slot 1, slot 2, and slot 3 every 500 ms by the timing synchronization process. The transfer request processing by the user terminal is a transfer request every 1500 ms from the viewpoint of one distributed recording server (for example, in the case of the distributed recording server 2, it corresponds to 901 and 904 shown in FIG. 9). This transfer request is made when the slot state specified by the channel number included in the transfer request packet every 1500 ms is reached (in this case, since channel 6 is allocated to the user terminal, slot 2 is ), And is controlled by the channel control unit 301 so that the video stream data requested from the transmission buffer 306 from the magnetic disk storage device 305 is read and transmitted. The read video stream data is added with the same sequential number as that stored in the transfer request packet by the video stream transmission unit 303, and transmitted to the user terminal as indicated by 906 to 909 shown in FIG.
[0052]
Further, a video stream reproduction process in the user terminal will be described.
[0053]
As described above, the video stream data transferred from each distributed recording server is received by the user terminal at a cycle of approximately 500 ms. The received video stream is temporarily stored in the reception buffer 406 prepared for each transfer source distributed recording server. After a certain period of time (500 ms here) after receiving the video stream data of the sequential number 1, the video stream restructuring unit 407 follows the timer interrupt of the timer counter 408 with a period of 500 ms from each reception buffer 406 in the order of the sequential number. The received data is sequentially extracted, the sequential number is removed, and the video stream data is output to the video stream reproducing unit 401. The video stream reproducing unit 401 reproduces and displays the video stream data.
[0054]
To stop the playback processing, the video stream playback unit 401 issues a stop instruction to the transfer request scheduler 404 to stop the transfer request.
[0055]
As described above, as can be seen from FIG. 9, the upper server 101 does not involve any part in the reproduction processing, and the processing of the upper server 101 does not increase significantly even if the number of user terminals to be distributed simultaneously increases. This is a feature of the present embodiment.
[0056]
Next, the trick play process will be described. First, the cueing reproduction processing as the special reproduction processing can be realized by the video stream reproduction unit 401 instructing the transfer request scheduler 404 to reproduce the transfer start request block with a value other than 1, and the other processing is performed in a normal manner. It is no different from playback processing.
[0057]
Here, a method for realizing fast-forward reproduction using the video stream recording information 501 shown in FIG. 5 as the special reproduction processing will be described. Note that “fast-forward playback” means that the divided video stream data is thinned out and played back. For example, in the case of fast-forward playback from the beginning of the video stream, transfer requests of block numbers 1, 5, 9, 13,... May be issued every 500 ms in the order of the distributed recording servers 2, 3, 1, 2,. . Here, the reason why the block numbers are thinned out by 4 is that the transfer request to the distributed recording server is repeated in the order of 2, 3, and 1. Further, if this order is kept, the random number is completely random. It is also possible to send transfer requests in the order of the proper block numbers.
[0058]
As described above, what kind of operation is performed based on the video stream recording information is determined only by the transfer request from the user terminal, and the feature of the present embodiment is that the host server and each distributed server are not involved at all. .
[0059]
[Modification]
This modification is different from the above-described embodiment in that the NTP protocol is used as a synchronization unit of each distributed server. The NTP protocol is a protocol used to adjust the internal time of a network terminal to a standard time. Using this mechanism, each distributed server communicates with the NTP server, so that the time of each distributed server internal management is all the same as the time of the NTP server.
[0060]
That is, the internal time of each distributed server can be completely synchronized, and the timing of slot switching can be specified by the time. If the slot switching cycle is specified in advance, the higher Multicast transmission of synchronization packets from the server becomes unnecessary.
[0061]
According to the video server system described above, the video stream recording information managed by the upper server is transferred to the user terminal, and the transfer request of the video stream data is issued from the user terminal to each distributed recording server. Load can be reduced. In particular, even when the number of user terminals to be simultaneously distributed increases or when it becomes necessary to calculate block numbers for special reproduction, the load (memory consumption, processing time) on the host server does not increase. Therefore, it is easy to cope with a large-scale video server system.
[0062]
Furthermore, what operations (playback and special playback) are performed based on the video stream recording information can be realized by changing the processing in the user terminal, and a flexible user terminal application can be created. It becomes.
[0063]
Further, since the number of distributed recording servers can be arbitrarily set according to the system scale, it is possible to handle a small system to a large system, and a highly scalable system can be configured. Further, since one video stream is divided and recorded in each distributed recording server, there is no need to copy one video stream to a plurality of recording servers, and the capacity of the magnetic storage disk device is effectively used. be able to.
[0064]
Furthermore, all of the components of the video server system, the upper server, the distributed recording server, and the user terminal, can be realized by operating the corresponding software on a general-purpose personal computer. It is not necessary, and is excellent in cost.
[0065]
Further, in the video server system of the modified example, in addition to the above-described effects, there is no need for the upper-level server to transmit the synchronization packet, and further, each distributed server does not need to receive the synchronization packet. Since the transmission / reception interval of the NTP packet may be much longer than the interval of the timing synchronization packet, the effect of reducing the processing of each terminal and the load on the network can be expected.
[0066]
Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), the present invention can be applied to an apparatus (for example, a copying machine, a facsimile device, etc.) including one device. May be applied.
[0067]
Further, an object of the present invention is to supply a recording medium in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (CPU or MPU) of the system or apparatus stores the recording medium in the recording medium. Needless to say, this can also be achieved by reading and executing the program code thus read.
[0068]
In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium storing the program code constitutes the present invention.
[0069]
As a recording medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like is used. be able to.
[0070]
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also an OS (Operating System) running on the computer based on the instruction of the program code. It goes without saying that a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.
[0071]
Further, after the program code read from the recording medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that a CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.
[0072]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a video data system that reduces the load on the host server and has excellent system expandability.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a video server system according to an embodiment.
FIG. 2 is a diagram illustrating a configuration of a host server 101 according to the present embodiment.
FIG. 3 is a diagram illustrating a configuration of a distributed recording server according to the embodiment.
FIG. 4 is a diagram illustrating a configuration of a user terminal according to the present embodiment.
FIG. 5 is a diagram illustrating an example of recording information according to the embodiment.
FIG. 6 is a diagram showing a relationship between a system slot and a server slot of each distributed recording server in the embodiment.
FIG. 7 is a diagram showing a format of a transfer request packet sent from a user terminal to each distributed recording server.
FIG. 8 is a diagram showing a timing synchronization process between a host server and each distributed server.
FIG. 9 is a diagram showing a data transfer request and a data transfer timing performed between a user terminal and each distributed recording server.
FIG. 10 is a diagram showing a configuration of a conventional video server.
[Explanation of symbols]
101 Host server
102 Distributed recording server 1
103 Distributed recording server 2
104 Distributed recording server 3
105 User terminal 1
106 User terminal 2
107 User terminal 3
108 user terminal 4
201 Distributed recording server management unit
202 User terminal management unit
203 Channel management unit
204 channel allocation table
205 Video stream recording information management unit
206 video stream recording information management table
207 Magnetic Disk Storage Device
208 Video stream recording information
209 Synchronous packet transmission unit
210 timer counter
211 Network Protocol
301 Channel control unit
302 Video stream transmission unit
303 read scheduler
304 channel allocation table
305 Magnetic disk storage device
306 transmission buffer
307 Host server communication unit
308 User terminal communication unit
309 Synchronous packet receiving unit
310 timer counter
311 Network Protocol
401 Video stream playback unit
402 upper server communication unit
403 Video stream recording information
404 Transfer request scheduler
405 Distributed recording server communication unit
406 receive buffer
407 Video stream reconstruction unit
408 Timer counter
409 Network Protocol

Claims (9)

An upper server that manages the recording information of the video content, a plurality of distributed recording servers that divide the video content into a plurality of video stream data and record, and a user terminal that reproduces the video content are connected via a network. Video server system,
Transmitting means for transmitting the recording information of the video content to the user terminal in response to the reproduction request for the video content from the user terminal,
Transfer request means for performing a transfer request of video stream data to each distributed recording server by the user terminal based on the recording information of the video content;
Transfer means for each distributed recording server to transfer video stream data to the user terminal in synchronization with the communication means,
A video server system, characterized in that the user terminal has reproduction means for reproducing video content based on each video stream data transferred from each distributed recording server. The video server system according to claim 1, wherein the network is an Internet or an intranet. 3. The video server system according to claim 2, wherein TCP / IP is used as said communication means, TCP is used for communication of control data, and UDP is used for communication of video stream data. 4. The video server system according to claim 3, wherein a synchronization packet is multicast-transmitted from the upper server, and each distributed recording server transfers the video stream data in synchronization with the received synchronization packet. 4. The video server system according to claim 3, wherein a synchronization packet is transmitted by IP multicast from the host server, and each distributed recording server transfers the video stream data in synchronization with the received synchronization packet. 4. The video server system according to claim 3, wherein the NTP protocol is used as the communication unit, and each distributed recording server transfers the video stream data in synchronization with a standard time. An upper server that manages the recording information of the video content, a plurality of distributed recording servers that divide the video content into a plurality of video stream data and record, and a user terminal that reproduces the video content are connected via a network. Video playback method of a video server system,
In response to a playback request for video content from the user terminal, the upper server transmits the recording information of the video content to the user terminal,
Based on the recording information of the video content, the user terminal makes a transfer request of video stream data to each distributed recording server,
Each distributed recording server transfers video stream data to the user terminal in synchronization by communication means,
A video reproduction method for a video server system, wherein the user terminal reproduces video content based on each video stream data transferred from each distributed recording server. Computer
Transmitting means for transmitting the recording information of the video content to the user terminal in response to the reproduction request for the video content from the user terminal,
Transfer request means for performing a transfer request of video stream data to each distributed recording server by the user terminal based on the recording information of the video content;
Transfer means for each distributed recording server to transfer video stream data to the user terminal in synchronization with the communication means,
An upper server that manages recording information of the video content, wherein the user terminal has a reproducing unit that reproduces the video content based on each video stream data transferred from each distributed recording server; A program for functioning as a video server system in which a plurality of distributed recording servers for dividing and recording data and a user terminal for reproducing the video content are connected via a network. A computer-readable recording medium on which the program according to claim 8 is recorded.

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