JPH08111689A - Server equipment - Google Patents

Abstract

PURPOSE: To provide the low-priced server equipment which improves response performance and processing efficiency. CONSTITUTION: Video data are divided into segment files(SF) of a fixed length and those SF are stored in information storage devices 101 to 103. Controllers 123 and 122 transmit information reading requests for requesting the SF just for a number less than a fixed value for fixed time and provide images for user devices 131 to 136. When the number of requests to be transmitted gets more than the fixed value, they are transmitted in advance. When reproduction or the change of a reproducing mode is requested from the user devices 131 to 136, the information reading request is immediately transmitted and the maximum value of time for reading at the information storage devices is reduced. Besides, any SF to be required after the change is selected from the buffers of controllers 121 and 122 and provided for the user devices 131 to 136.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a server device for accumulating information such as moving images and voices, which requires real-time reading.

[0002]

2. Description of the Related Art In recent years, not only a server device that handles computer data but also a server device that handles moving images and voices have become necessary, and along with this, real-time property of information transmitted from the server device is desired. .

Japanese Patent Application No. 05-269995 "Video Server" shows a video server in which a plurality of storage devices storing video data are connected by a switching device.
In this video server, video data of a program provided to a user is divided and stored in a plurality of storage devices. Then, the video data divided and stored in the storage device is sent to a plurality of users in the form of a video stream via the exchange device.

[0004]

However, in the above configuration, when video data stored in a plurality of storage devices is independently provided to a plurality of users,
Information read-out requests from a plurality of users may be simultaneously made to one storage device. At this time, waiting for reading of information occurs.

In order not to cause this, the reading capacity of the storage device must be made sufficiently larger than the amount of information actually read.

Further, when waiting for reading of information from the storage device occurs, as a result, the information traffic for the same user read from another storage device may collide with the switching device.

When the information traffics collide with each other in the exchange, a transmission wait occurs there, or a packet carrying information is discarded in the exchange. In order to prevent this, the exchange capacity of the exchange must be sufficiently large with respect to the traffic volume to be exchanged.

That is, when the system disclosed in Japanese Patent Application No. 05-269995 "Video Server" is used to secure a quick response to requests from a plurality of users, the information is read from the storage device. However, there is a problem that the capacity of the exchange and the exchange capacity of the exchange must be sufficiently large with respect to the traffic volume to be actually processed. In view of the above problems, the present invention provides a server device capable of more efficiently utilizing the read performance of information from a storage device and the exchange performance of an exchange device while ensuring a quick response to a request from a user. With the goal.

[0009]

In order to solve the above problems, a server device of the present invention divides video data into fixed-length segment files (SF), and stores one or a plurality of information storing the SFs. A device and a plurality of control devices are connected to a switching device, a single or a plurality of user devices are connected to the control device, and the control device requests the information storage device to read out the SF. In a server device that sends a read request, acquires the SF, and sends a video stream to the user device, the number of the information read requests that each control device sends within a certain period of time. Is limited to a certain value or less.

Then, the time at which the information read request should be sent is determined from the playback speed of the video stream provided to the user device and the amount of information per SF, and the information read is sent within a fixed time. In order to prevent the number of output requests from exceeding a certain value, the time to send the information read request is set to the time to be sent or a time before the time to be sent. .

In the information read request, a delay limit value which is an upper limit value of the time required to read the SF stored in the information storage device is described. In the information storage device, the delay limit value is described. The requested SF reading is completed from the reception of the information reading request to the elapse of the delay limit value, and the reproduction from the user device or the special reproduction including the double speed reproduction and the triple speed reproduction is performed. ,
When there is a request to change the playback mode such as normal playback, the delay limit value for single or multiple information read requests is temporarily set to a value smaller than the delay limit value for normal information read requests. It is provided with a configuration for sending the data after that.

When requesting the reading of the data from an information storage device that stores data other than video data that does not require real-time processing, a delay limit value of the information reading request that requests the reading of SF. In addition to the delay limit value set to a larger value than the above, a configuration for sending a request for reading data is provided.

Further, immediately after the control device receives a request for reproducing a video from the user device, a special reproduction such as double speed reproduction or triple speed reproduction, or a request for changing the reproduction mode such as normal reproduction, Even when the number of information read requests to be sent within the fixed time has reached a fixed value, a single or plural information read requests are sent.

Further, the control device manages the number of information read requests to be sent within a fixed time by setting an upper limit value so as to be a fixed value or less for each reproduction speed of the provided video stream.

Alternatively, the control device determines the time at which the information read request should be sent from the reproduction speed of the video stream provided to the user device and the amount of information per SF, and the information read request is issued. The transmission timing for transmitting the information is provided at every reproduction time of one frame of the video, and the number of transmission of the information reading request at the transmission timing is controlled to be a certain value or less, and the information reading request should be transmitted. When the number of transmissions exceeds a certain value at the timing, the information read requests for the number of excesses are transmitted after delaying the reproduction time of one frame of the video, and the video stream is transmitted to the user device. Has a configuration for transmitting the video data of the already transmitted frame to the user apparatus again.

[0016] Alternatively, when sending a video stream to the user device, a command for holding the sent video frame for a reproduction time of one frame is sent to the user device. It is equipped with.

Further, the control device sends an information read request in advance within a range in which the exchange capability of the exchange device and the read capability of the storage device are allowable, obtains the SF, and sets it in the control device. After the SF is stored in the buffer stored in the buffer, the SF is supplied to the user apparatus as a video stream, and when the user apparatus requests the reproduction mode change, only the SF required after the reproduction mode change is selected from the SFs in the buffer. It is provided with a configuration for selecting and transmitting the changed video stream to the user device.

[0018]

According to the present invention, by the above-described configuration, the number of information read requests sent by the control device within a fixed time is set to a fixed value or less, so that the amount of SF read processing and transmission processing is smoothed in time. It is possible to improve the SF read performance of the information storage device and the exchange performance of the exchange device.

Further, when the number of transmissions reaches the maximum value and cannot be transmitted at the time when the information reading request should be transmitted, the delay due to the deviation of the transmission time is eliminated by transmitting before the time when the information should be transmitted. It becomes possible to do.

Further, when the video reproduction is started or the reproduction mode is changed, the delay allowable value is made smaller than the normal value, so that the service can be started or changed at a high response speed in response to the request from the user apparatus. In addition, the performance of reading SF from the information storage device can be improved.

For data that does not require real-time processing, by setting a large delay limit value, the processing in the information storage device can be further smoothed in time and the processing performance can be improved.

Then, at the time of starting the reproduction of the video or changing the reproduction mode, even if the number of information read requests to be sent within a certain time has reached a certain value, by sending the information read request, the user device can It is possible to start or change the service with a fast response speed to the request.

Regarding the amount of information read request transmission, by managing the total amount for each video reproduction speed, simple and efficient management can be realized.

Alternatively, the time interval of the transmission timing is
The time for sending one video frame is set, and when the number of simultaneous sending requests is the maximum, the sending timing of the information reading request is set to 1
When the playback time of the frame is delayed and the video is supplied to the user device, the same frame is supplied twice, or the transmitted video frame is instructed to be retained for the reproduction time of one frame for a long time. The requested image can be provided with a quick response to the request, and the processing in the information storage device and the exchange device can be temporally smoothed to improve the processing performance.

Further, when the reproduction mode is changed, it is possible to read out the SF from the information storage device and transmit it by sending out the SF that is necessary after the change among the SFs stored in the buffer of the control device. Since the reproduction mode can be changed without waiting, it is possible to change the image with a quick response to the reproduction mode change request from the user device.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A server device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a server device according to an embodiment of the present invention. In FIG. 1, 1
Reference numerals 01, 102, and 103 denote information storage devices that store information and, when an information read request is issued from the outside, read and transmit designated information. Reference numerals 131 to 136 denote user devices of the server device, and each user device receives information from the server device. 121, 122
Indicates a control device that sends an information read request in response to a request from the user device, and sends the information transmitted from the information storage device to the user device. 111 is the control device 1
21, 122 and the information storage devices 101 to 103 are connected to each other to show an exchange device for exchanging information and requests.

The operation of the server device configured as described above will be described below with reference to FIGS.

Video data is divided into segment files (SF) and stored in the information storage devices 101 to 103 in FIG. For example, when the user device 131 requests reproduction of the video of a certain program, the control device 121 issues an information read request to the information storage device in which the video data is stored. Since the video data is divided and stored in the SF, the control device 121 issues the information read request in the order of the reproduction order, with the frequency at which the information amount corresponding to the reproduction speed of the video stream is obtained. Information storage devices 101 to 103 that have received the information read request
Reads the designated SF, and the control device 121
A packet having SF as an information element is transmitted to. The control device 121 controls the order of the SFs transmitted from the information storage devices 101 to 103 and absorbs the delay fluctuation, and provides the video to the user device.

FIG. 8 shows an example of the message format of the information read request. The information read request is message identification information for identifying the message, identification information for the destination information storage device, recording position identification information for identifying the SF recording position in the information storage device, and identification for identifying the transmission source control device. The information element includes information, identification information for identifying the user device that provides the read SF, and a delay limit value that defines the maximum value of the time required for reading the SF in the information storage device. Further, FIG. 9 shows an example of a message format of a packet having SF as an information element transmitted from the information storage device to the control device.
A packet having SF as an information element includes message identification information, user apparatus identification information for identifying a user apparatus to which the SF is provided, identification information for identifying a destination control apparatus, and SF as information elements. Only the SF described here is sent from the control device 121 to the user device 131 as video information.

FIG. 2 shows control devices 121 and 1 in the server device.
22 shows the configuration of No. 22. In FIG. 2, 201
Indicates a request reception unit that receives a video reproduction request or a reproduction mode change request from the user devices 131 to 136, determines acceptance of the request, and, when accepting, notifies the acceptance. Reference numeral 202 denotes a traffic amount management unit that manages the issuance amount of the information read request in order to manage the traffic amount of the SF transmitted from the information storage devices 101 to 103. Reference numeral 204 denotes a sending interval management unit that manages a time interval for sending the information reading request, and 203 denotes the maximum value of the number of information reading requests that can be sent at each time and the actual sending for each time. 4 shows a transmission number management unit that manages the number of information read requests to be made. The maximum value is managed by setting an upper limit value for each video playback speed. Reference numeral 205 denotes a delay limit value management unit that manages the maximum value of the time from the arrival of a request to the completion of reading of information in the information storage devices 101 to 103. In the delay limit value management unit 205, the initial value of the first delay limit value for the information reading request sent immediately after the request from the user device and the second delay limit value for the other requests. Manages the initial value of. The initial value of the first delay limit value is set to be smaller than the initial value of the second delay limit value. Reference numeral 206 denotes a sending control unit that controls sending of the information reading request in response to the received request from the user device. Also, 207 is
4 shows a video providing unit that performs sequence control of segment files transmitted from an information storage device and absorbs delay fluctuations to provide video to a user device.

When a request for reproducing a program arrives from the user device 131, the request receiving unit 201 causes the traffic volume management unit 2 to operate.
02 is inquired as to whether or not the reproduction request can be accepted. The traffic volume management unit 202 manages the number of users that can be accepted for each video reproduction speed, and also manages the total traffic volume of the video data sent from the control device to the user device. Judge the reception. When it is determined that the request from the user device 131 can be accepted, the request accepting unit 201 starts the operation of sending the information reading request. The information read request is transmitted according to the transmission interval managed by the transmission interval management unit 204.

The information read-out request is controlled so that it is sent out by a fixed number or less at the sending timing of every fixed time. The time interval of the transmission timing and the number of requests that can be transmitted per transmission timing are determined in consideration of the processing capacity of the information storage device, the exchange capacity of the exchange device, and the allowable delay limit value.

The time intervals of the transmission timings are managed by the transmission interval management unit 204, and the number of requests that can be transmitted per transmission timing is the actual number of transmissions and the number of transmissions management unit 2
It is managed by 03. The number of requests that can be transmitted per transmission timing is further managed by setting an upper limit value for each video reproduction speed. FIG. 16 shows an example of management items.

Next, the method of calculating the pattern of the transmission intervals of the information reading request for each user device will be described.
It is assumed that the time interval of the transmission timing is t (s), the video reproduction speed is v (bit / s), and the size of SF is n (bit).
The sending interval A is determined by the calculation formula shown in Formula 1.

A = [n / (t × v)] (Equation 1) However, the symbol [x] represents the maximum integer not exceeding x.

If the request is continued at the transmission interval A, more SFs than the video reproduction speed will be acquired.
In order to avoid this, the correction parameter B is introduced and corrected. The correction parameter B is calculated by Equation 2.

B = [A / {n / (t × v) −A}] + 1 (Equation 2) One information read request is issued at every transmission interval A over B times.
Requests are sent one by one, and no information read request is sent at a time after the next sending interval A. Repeat this. According to the above-mentioned pattern of the transmission interval, the scheduled transmission time of the information read request is determined and the information read request is transmitted. However, even with the correction parameter B, the acquired SF is slightly higher than the video reproduction speed. For this reason, in the video providing unit 205, the S waiting for transmission to the user device is sent.
The amount of F will increase. When the number of SFs waiting to be sent exceeds a certain value, the image providing unit 205 controls not to send the information read request once.

Further, when the reproduction mode is changed, the pattern of the transmission interval becomes the initial state. That is, in the case of a change, from that point onward, B times,
One information read request is sent at every sending interval A,
At the time after the next transmission interval A, the operation of not transmitting the information read request is repeated.

A parameter of delay limit value is added to the information reading request transmitted from the control device 121 according to the transmission interval described above, and the information storage device 10 is provided.
In 1 to 103, SF is read within the delay limit value. The SF that has been read out by the information storage devices 101 to 103 within the delay limit value and transmitted is received by the video providing unit 205. The image providing unit 205 performs sequence control between SFs and absorbs delay fluctuations, and provides images to the user device.

In FIG. 7, the transmission timing time interval, the transmission interval, the SF reception interval, and the S
The relationship of the intervals for transmitting F is shown. In Figure 7, t = 50m
The relationship between t, A, and B is shown by taking the case of s, v = 4 Mbit / s and n = 512 kbit as an example. In FIG. 7, 7
01 is an arrow indicating that the time advances. 702, 70
Reference numeral 3 is an auxiliary arrow indicating the time interval t of the transmission timing. The scales given above the arrow 701 respectively indicate the sending timing. Reference numerals 704 to 715 are arrows indicating the timing of sending the information read request. now,
The case of A = 2 and B = 4 is described as an example. Therefore, the distance between the arrow 704 and the arrow 705, the arrow 705 and the arrow 70
The interval between 6 is twice the interval of the time interval t of the transmission timing (A = 2). Further, after the transmission of four information reading requests has been completed (B = 4), no information reading request is transmitted after the transmission interval A. Therefore, the distance between the arrows 707 and 708 is twice the distance A. Reference numerals 716 to 723 are arrows indicating the timing at which the SF arrives at the video providing unit 205, and 724 to 731 are SFs as videos to the user apparatus.
Is an arrow indicating the timing of starting the transmission. Arrow 70
In response to the information read request sent at the timing of 4, the S read from the information storage device 101, for example,
F arrives at the control device 121 at the timing of arrow 716, and the transmission of SF information to the user equipment is started at the timing of arrow 714.

Next, a mechanism for transmitting the information read request of each user device while limiting the number of transmission requests at each transmission timing will be described with reference to FIG. FIG. 3 shows the configuration of the sending control unit 206. Reference numeral 301 denotes a sequence management unit that manages the SF storage position and the reproduction order of the video being reproduced for each user device. Reference numeral 302 denotes a clock that measures time in units of transmission timing, and 303
Shows a scheduled transmission time calculation unit that calculates the scheduled issue time of the information read request with reference to the transmission interval management unit 204. Reference numeral 304 denotes an actual transmission time calculation unit that calculates the time to be actually transmitted, based on the requested transmission number managed by the transmission number management unit 203 and the scheduled transmission time managed by the scheduled transmission time calculation unit 303. 305 is a delay limit value management unit 20
5 and information from the actual transmission time calculation unit 304,
3 shows a delay limit value calculation unit that calculates a delay limit value. 306
Indicates an actual transmission time calculated by the actual transmission time calculation unit 304 and an actual transmission time and delay allowable value management unit that stores the delay limit value calculated by the delay limit value calculation unit 305. Reference numeral 307 denotes a reading request sending unit that sends a reading request at the sending time.

When a program reproduction request from the user device arrives at the request reception unit 201, the request reception unit 201 notifies the sequence management unit 301 and the scheduled transmission time calculation unit 303 of this. The sequence management unit 301 prepares a file in which the SF storage location and the transmission order are described so that the SF of the program requested by the user device can be provided in the reproduction order. The operation of the scheduled transmission time calculation unit 303 will be described with reference to the flowchart of FIG. First, for the information read request issued only after the request arrives from the user device, the scheduled sending time is set to the time of the next sending timing so that it can be issued immediately. (Step S4 of FIG. 4
(Operations of 1 and S42) A plurality of scheduled transmission times are set so that a plurality of information reading requests are issued at the same time when the reproduction of the video is started or when the reproduction mode is changed. Then, the actual delivery time calculation unit 304 is notified of the scheduled delivery time (step S43 in the figure). Further, the sending interval management unit 204 is instructed to return the sending interval pattern to the initial state (step S44 in the figure). The scheduled transmission time is sequentially calculated according to the pattern of the transmission intervals managed by the transmission interval management unit 204 (steps S45, S).
46). Then, the calculated scheduled sending time is notified to the actual sending time calculating unit 304. The actual delivery time calculation unit 304 calculates the actual delivery time based on this, and this operation will be described with reference to the flowchart of FIG.

FIG. 5 is a flow chart for explaining the operation of the actual sending time calculator 304. The actual delivery time calculation unit 304 performs the operation described below each time the scheduled delivery time calculation unit 303 calculates a new scheduled delivery time.

When the scheduled sending time is the time of the next sending timing, the scheduled sending time is directly used as the actual sending time (steps S51 and S53 in FIG. 5).
In other cases, at the scheduled transmission time, the number of requests already set as the transmission time is set to the transmission number management unit 203.
See more. If the referred number of requests has not reached the maximum value, the scheduled transmission time is set as the actual transmission time (steps S52 and S53 in the figure). When the maximum value is reached, the time of the immediately preceding transmission timing of the scheduled transmission time is set as the scheduled transmission time (step S54 in the figure), and the time difference from the time calculated by the scheduled transmission time calculation unit 303 is calculated. It is stored (step S55 in the figure). Then, it is confirmed whether or not the new scheduled sending time is the next sending timing (step S51 in the figure). If it is not the next sending timing, the requested number is referred to, and if the maximum value is not reached, The scheduled sending time is set as the actual sending time (step S5 in the figure).
3). If the maximum value has been reached, it is checked again whether the scheduled sending time is the next sending timing (step S in FIG.
51), the same processing is repeated. In such an algorithm, if the maximum values are set at all the transmission timings between the initially set scheduled transmission time and the next transmission timing, the maximum value will be exceeded at the next transmission timing. In order to avoid this, the scheduled transmission time is calculated in advance for a fixed time or longer. The minimum value of the fixed time here can be determined by the cycle of the request transmission interval pattern for each video reproduction speed.

As described above, in order to determine the actual sending time and to update the sending request number at the actual sending time, this is notified to the sending number management section 203 (step S56 in the figure). . Further, the time difference from the time calculated by the scheduled transmission time calculation unit 303 is the delay limit value calculation unit 305.
To notify. Upon receiving the notification from the actual transmission time calculation unit 304, the transmission number management unit 203 updates the number of transmission requests managed at each time, and the delay limit value calculation unit 305
The delay limit value is calculated. The delay limit value is obtained by adding the initial value of the delay limit value managed by the delay limit value management unit 205 and the time notified by the actual transmission time calculation unit 304. After the request from the user device arrives, the initial value of the first delay limit value is selected as the delay limit value of the information read request that is issued first, and the second limit value is selected for the others.
Select the initial delay limit value of.

The actual sending time and delay limit value calculated as described above are stored in the actual sending time and delay limit value management unit 306.

Next, the operation of the read request sending unit 307 when the actual sending time comes will be described. The read request transmission unit 307 refers to the clock 302 and the actual transmission time and delay limit value management unit 306 to check whether the actual transmission time has come. When the actual transmission time comes, the information indicating the storage location of the SF to be transmitted is acquired from the sequence management unit 301, and the delay limit value information is acquired from the actual transmission time and delay limit value management unit 306. . Then, the acquired information is added and an information read request is sent.

Next, the operation of the image providing unit 207 when the SF read from the information storage device arrives at the control device by transmitting the information read request will be described. The image providing unit 207 is configured as shown in FIG. In FIG. 6, reference numeral 601 denotes an SF reception unit that receives the SF packet transmitted from the information storage device and stores the received SF packet in the buffer. Reference numeral 602 is an SF that calculates and manages the time at which the SF is sent to the user apparatus.
The sending time management part is shown. Reference numeral 603 indicates a clock, and 604
Refers to the sending time managed by the clock 603 and the SF sending time management unit 602, and when the sending time comes, extracts the SF information from the SF packet in the buffer,
6 shows an SF sending unit for sending to a user device. A method of calculating the transmission time in the SF transmission time management unit 602 will be described next. First, the request receiving unit 201 notifies that a request from the user device has arrived. In that case, SF
The sending time management unit 602 calculates the latest time among the times at which the SF obtained by the information reading request, which is sent first after the request from the user device arrives, arrives. This is the actual transmission time and delay limit value management unit 30.
The delay limit value is added to the time at which the information read request is sent, which is managed in 6, and the worst value of the delay in the network held by the SF sending time management unit 602 is added, It is calculated. Also, the reproduction start time is calculated so that the video information to be transmitted will not run out from the arrival of the first SF packet until the arrival of the next SF packet. The time calculated as described above becomes the time when the transmission of the video to the user device is started, and the SFs are sequentially transmitted from this time. The second and subsequent SFs are 1
It is sequentially set at the time when the transmission of the information of the immediately preceding SF is completed. The time interval of the SF transmission start time is determined by the reproduction speed of the video provided to the user device. The SF sending time management unit 602 also refers to the actual sending time and delay limit value management unit 306 to count the number of information reading requests sent after the request arrives from the user device. Furthermore, the number of SFs sent to the user apparatus is also counted by referring to the SF sending unit 604. Then, when the difference between the transmitted information read request and the number of transmitted SFs exceeds a certain value, it is judged that the SF read is excessive and the information read request is canceled once. In the image providing unit 207, the SF transmitted from the information storage device
Is received, SF is stored in the buffer until the sending time.
Is stored. When the sending time comes, the video is provided to the user apparatus by sending the SF.

Next, the operation of the information storage device 101 will be described with reference to FIG. FIG. 10 is a diagram showing a configuration of a portion of the information storage device 101 which reads out and transmits SF in response to an information reading request from the control device. In FIG. 10, reference numeral 1001 denotes a request information management unit that manages information about an information read request that has arrived at the information storage device and has not completed the SF transmission processing. In the request information management unit 1001, for each request, message identification information, user device identification information, sequence number, destination control device identification number, recording position identification information, request arrival time, delay limit value, and SF transmission time. , Stores an identifier for identifying whether or not the reading is completed. Based on this information, S
Reading and transmission of F are performed. Reference numeral 1002 denotes a request receiving unit that receives an information read request from the control device.
Reference numeral 1003 denotes a request information registration unit that causes the request information management unit 1001 to store the information given as parameters in the information reading request, the arrival time of the request, and the SF transmission time. Reference numeral 1004 denotes an SF reading control unit that controls reading of SF. Reference numeral 1005 indicates a disk in which SF is stored, and 1006 indicates a buffer memory in which the SF read from the disk 1005 is temporarily stored. 1007 checks whether the SF has been read from the disk at the time of sending the SF, and then
6 shows an SF transmission determination unit that issues an SF transmission instruction or a discard instruction. Reference numeral 1008 denotes a discard processing unit that discards SFs that have not been read from the disk even at the sending time, and 1009 denotes SFs that perform SF transmission processing.
Indicates a transmitter. 1010 shows a clock.

The information reading request arrived from the control device 121 is received by the request receiving section 1002, and the request information registration section 1003 registers information on the request. The arrival time of the request is stored with reference to the clock 1010, S
The transmission time of F is the time when the delay limit value is added to the arrival time of the request. The request information registration unit 1003 notifies the SF read control unit 1004 of the arrival of the request. The operation of the SF read control unit 1004 at this time is shown in FIG.
1 will be described with reference to the step diagram of 1.

The information read request notified of arrival by the request information registration unit 1003 is stored in the read waiting queue provided corresponding to the disc. The location of the queue is determined according to the algorithm described below.

First, the processing time of the request in the read waiting queue is added from the head of the queue to obtain the last position (processable position) that can be processed within the delay limit value (FIG. 11).
Step S111). A position where the seek time can be most shortened from the head of the queue to the processable position is selected (step S112 in the figure). When the processing is performed at the selected position, it is checked whether all the postponed requests can be read out and processed within the delay limit value (step S in the figure).
113). If it is possible, the request is stored in the selected position (step S114 in the figure). If the request cannot be made, it is checked whether or not the request that cannot be made exists in the request after the processable position (step S115 in the figure). If the request exists, the request is discarded without being stored in the queue (step S117 in the figure). If it does not exist, the request is stored in the processable position (step S116 in the figure). The requests in the read waiting queue are sequentially read from the head in the order of SF reading from the disk, and when the processing is completed, the requests are taken out from the queue.

In order to transmit the SF stored in the buffer memory as described above, the SF transmission determining unit 1007
Works as follows. First, the SF transmission determination unit 1007
Monitors the sending time of the SF stored in the request information management unit 1001. Then, when the SF transmission time comes, it is checked whether the reading is completed, and if it is completed, a transmission instruction is given to the SF transmission unit 1009. If not completed, a discard instruction is issued to the discard processing unit 1008. When the transmission is instructed, the SF transmission unit assembles the packet based on the information of the request information management unit and transmits the SF to the control device. On the other hand, when the discard instruction is given, the discard processing unit 1008 discards the information read request that has not been read from the disc, and the SF that is reading from the disc interrupts the read. Then, the SF information is discarded.

As described above, according to the present embodiment, the number of request transmissions at each transmission timing is limited, and the number of information read requests transmitted within a certain time is set to a certain value or less. , The amount of SF read processing and transmission processing is smoothed in time, and the SF read performance of the information storage device and the exchange performance of the exchange device can be improved.

Further, when the number of transmissions reaches the maximum value at the transmission timing at which the information read request should be transmitted and the transmission is not possible, the transmission timings before the transmission timings to be transmitted are transmitted to shift the transmission timings. It is possible to eliminate the delay due to.

Further, when the video reproduction is started or the reproduction mode is changed, a plurality of requests are transmitted and the delay allowable value is made smaller than the normal value to start the service at a high response speed with respect to the request from the user device. It is possible to change it, and it is possible to improve the performance of reading SF from the disc.

Further, at the time of starting the reproduction of the image or changing the reproduction mode, the information read request is immediately transmitted, so that the response speed to the request from the user device is high.
It is possible to start or change the service. This can be applied even when the buffer capacity of the control device has no margin by starting the SF transmission after the delay limit value is reached in the information storage device. Regarding the transmission amount of the information read request, the traffic amount management unit manages the total amount according to the transmission speed of the video, so that the transmission amount can be managed easily and efficiently with little fluctuation in time. realizable.

A second embodiment of the present invention will be described below with reference to the drawings. Since the basic configuration such as the configuration of FIG. 1 is the same as that of the first embodiment, duplicate description will be omitted here. In the second embodiment, first, when the reading request sending unit 307 detects the sending timing at which the number of sending requests does not reach the upper limit, it sends the reading request scheduled to be sent next, in advance. The operation of obtaining a large number of SFs is performed. In addition, the image providing unit 207
It has the configuration shown in FIG.

In FIG. 12, reference numeral 1201 denotes an SF receiving unit which receives the SF transmitted from the information storage device and stores the received SF in the buffer. Reference numeral 1202 denotes an SF sending time management unit that calculates and manages the time at which SF is sent to the user apparatus. Reference numeral 1203 denotes an SF editing unit that performs an operation of editing the SF that has already arrived at the control device and has not been sent to the user device when the playback mode is changed, and recreating the edited video data after the playback mode is changed.

Reference numeral 1205 denotes a clock, and 1204 refers to the clock 1205 and the transmission time managed by the SF transmission time management unit 1202. When the transmission time comes, the SF in the buffer is transmitted to the user apparatus. The SF sending unit is shown.
The calculation method of the transmission time in the SF transmission time management unit 1202 is the same as the calculation method in the SF transmission time management unit 602 described in the first embodiment. However, when changing the playback mode,
The changed video will be transmitted before the transmission start time calculated here. This is the SF editor 1303
Is realized by

The operation of the SF editing section 1203 here will be described with reference to FIG. First, the SF editorial department
Of the intervals for sending SF to the user device, which is obtained by referring to the SF sending time management unit 1202, the shortest interval a is stored for each user. Then, when the SF sending time management unit 1202 is notified that the playback mode change request has been received from the request receiving unit 201, the SF sending time management unit 1202 notifies the SF editing unit 1203 of this (FIG. 13). Step S13
1), the SF editing unit 1203 operates as follows.

The SF editing section 1303 checks the information amount N of the SF stored in the buffer memory (step S132 in the figure). Then, the interval Y until the SF that is read from the information storage device and arrives at the control device is sent to the user device in response to the information read request that is sent for the first time after the reproduction mode change request is issued is determined by the SF sending time management unit. Reference is made from 1202 (step S133 in the figure).

Then, the interval Y is divided by the stored interval a to calculate the information amount M of the SF to be sent to the user device during the interval Y (step S134 in the figure). here,
The information amount M of SF is calculated by the equation 3.

M = [Y / a] +1 (Equation 3) Here, the symbol [x] represents the maximum integer not exceeding x. Of the information amount N in the buffer memory, the ratio of the information amount required after the change is 1 / X.

Next, the information amount Z of SF is assumed. Here, it is assumed that only the SF information amount Z is transmitted to the user device before the reproduction mode is changed, and after the SF information amount Z is transmitted, the changed image is transmitted to the user device.

In order to provide the SF information to the user equipment without interruption, the following equation 4 must be established for the SF information amount Z.

Z + (M−Z) × X ≦ N (Equation 4) The maximum Z satisfying Equation 4 is calculated by Equation 5 (step S135 in the figure).

Z = (M × X−N) / (X−1) (Equation 3) If Z is 0 or less, editing is performed immediately and the changed image is transmitted (steps S 136 and S 137 in the figure). ). Z
If is larger than 0, editing is performed so as to start the change after transmitting the information amount Z of SF to the user device (steps S136 and S138 in the figure).

As described above, according to the second embodiment, an extra SF is acquired in advance, and when the reproduction mode is changed, the SF stored in the buffer of the control device is edited and temporarily stored. By changing the playback mode, the playback mode can be changed without waiting for the SF to be read from the information storage device and transmitted. Therefore, the image can be changed with a quick response to the playback mode change request from the user device. Is possible.

The third embodiment of the present invention will be described below with reference to the drawings. Since the basic configuration such as the configurations of FIGS. 1 and 2 is the same as that of the first embodiment, the duplicate description will be omitted here.

First, the time interval of the transmission timing managed by the transmission interval management unit 204 is the time for transmitting one frame of video. The configuration of the sending control unit 206 is the same as that of the first embodiment, but the operation is different. The operation of the third embodiment will be described below.

The sequence management unit 301 and the clock 302,
The actual operation of the transmission time / delay limit value management unit 306 and the read request transmission unit 307 is the same as the operation described in the first embodiment. Operations of the scheduled transmission time calculation unit 303, the actual transmission time calculation unit 304, and the delay limit value calculation unit are as described below.

First, the operation of the scheduled transmission time calculating section 303 will be described with reference to the flowchart of FIG. First, the information read request issued only after the request arrives from the user device sets the scheduled sending time at the time of the next sending timing so that it can be issued immediately (operations of steps S141 and S142 in FIG. 14). A plurality of scheduled transmission times are set so that a plurality of information reading requests are issued at the same time when the reproduction of the video is started or when the reproduction mode is changed. Then, the actual transmission time calculation unit 304
To the scheduled transmission time (step S14 in the figure)
3). Further, the sending interval management unit 204 is instructed to return the sending interval pattern to the initial state (step S144 in the figure). Then, the pattern of the transmission intervals managed by the transmission interval management unit 204 is referred to (step S1 in the figure).
45). Next, the actual delivery time calculation unit 304 waits for notification of the actual delivery time registration (step S14 in the figure).
6). When notified, the scheduled transmission time is calculated from the notified time and the pattern of the transmission interval (step 14 in FIG. 14).
7). The calculated scheduled sending time is notified to the actual sending time calculating unit 304 (step S148 in the figure), and the actual sending time calculating unit 304 determines the actual sending time based on the notified scheduled sending time. . Then, the scheduled sending time calculation unit 303 determines the next sending time based on the actual sending time (steps S145 to S147 in the figure).
Repeat this.

Next, the operation of the actual sending time calculating section 304 will be described with reference to the flowchart of FIG. FIG. 15 is a flow chart for explaining the operation of the actual sending time calculation unit 304. The actual transmission time calculation unit 304 performs the operation described below each time the scheduled transmission time calculation unit 303 calculates and notifies a new scheduled transmission time.

First, for the information read request issued only after the request arrives from the user device, the scheduled transmission time is used as it is as the actual transmission time so that it can be issued immediately (steps S151 and S154 in FIG. 5). In other cases, the number of requests management unit 203 refers to the number of requests already set as the sending time at the scheduled sending time. If the number of requested requests does not reach the maximum value, the scheduled transmission time is set as the actual transmission time (step S152 in the figure,
S154). If the maximum value has been reached, the time of the sending timing one time after the scheduled sending time is set as the actual sending time (steps S153 and S154 in the figure). The determined actual transmission time is notified to the scheduled transmission time calculation unit 155.

The delay limit value calculation unit 305 does not consider the time difference between the scheduled transmission time and the actual transmission time, and determines the first delay limit value or the second delay limit value managed by the delay limit value management unit 205. The delay limit value of is the delay limit value of each information read request. The video providing unit supplies the SF received from the information storage device to the user device.
Since there is an information read request that is being sent with a delay in the sending timing, the SF information to be sent to the user device may not be appropriate. At this time, the video information of the same frame is sent to the user apparatus twice to maintain the video continuity.

As described above, according to the third embodiment, the time interval of the transmission timing is set to the time for transmitting one video frame, and when the number of simultaneous transmission requests is the maximum, the information read request is transmitted. Delay the sending timing by one timing,
When video is supplied to the user device, the same frame is supplied twice to realize a quick response to the request from the user and to smooth the processing in the information storage device and the exchange device in time. You can

Although the present invention has been described above based on the embodiments, it goes without saying that the present invention is not limited to the above embodiments. That is, in the embodiment (1), the SF is stored in the disk in the information storage device, but the present invention is not limited to this. (2) In the embodiment, the case where two types of initial values of the delay limit value are provided has been described, but this is not limited. You may provide three or more types and perform more detailed control. Further, in a server device in which media other than video are mixed, a very large value can be set as a delay limit value for data such as a still image in which demand for delay is not severe. (3) In the first embodiment, the transmission of the SF packet from the information storage device is started after the delay limit time after the arrival of the information read request, but there is a margin in the buffer memory on the control device side. If so, the SF may be read from the disc and immediately transmitted. (4) In the first embodiment, the SF is read from the disk within the delay limit time, but the following method can be considered. In the information storage device, the maximum read time is set separately from the delay limit value,
SF is read within the maximum read time. The transmission of the SF read after the time of the delay limit value after the arrival of the information read request is permitted.

This method may or may not be applicable depending on the setting of the delay limit value and the required performance, but it is not necessary to perform the operation of step S111 in FIG. 11, and the reading order is determined. The processing up to can be simplified. (5) In the third embodiment, the time interval of the transmission timing is set to the time for transmitting one video frame, and when the number of simultaneous transmission requests is the maximum, the transmission timing of the information read request is delayed by one timing, and the user device It is assumed that the same frame is supplied twice when the video is supplied to the user device. However, a command instructing to hold the sent video frame for a reproduction time of one frame may be sent to the user device.

[0081]

As described above, according to the present invention, the number of information reading requests sent by the control device within a certain time is set to a certain value or less, so that the SF reading performance of the information storage device and the exchange device can be improved. It is possible to improve the exchange performance of the.

If the number of transmissions reaches the maximum value at the time when the information reading request should be transmitted and the information cannot be transmitted, the delay due to the deviation of the transmission time is eliminated by transmitting before the time when the information should be transmitted. It becomes possible to do.

Further, when the video reproduction is started or the reproduction mode is changed, the delay allowable value is set smaller than the normal value, so that the service can be started or changed at a high response speed in response to the request from the user apparatus. In addition, the performance of reading SF from the information storage device can be improved.

For data that does not require real-time processing, by setting a large delay limit value, the processing in the information storage device can be further smoothed in time and the performance can be improved.

Then, at the time of starting the reproduction of the video or changing the reproduction mode, even if the number of information read requests to be sent at a constant time has reached a fixed value, the information read request is sent so that the user device sends a request. It is possible to start or change a service with a fast response speed to a request.

With regard to the amount of information read request transmission, by managing the total amount for each video reproduction speed, simple and efficient management can be realized.

Alternatively, the time interval of the transmission timing is
The time for sending one video frame is set, and when the number of simultaneous sending requests is the maximum, the sending timing of the information reading request is set to 1
Delay the playback time of the frame and supply the same frame twice when supplying the video to the user device, or
By transmitting to the user device a command instructing to hold the transmitted video frame for a reproduction time of one frame, the information storage device and the exchange device can respond to the request from the user device with a quick response. The processing can be smoothed over time, and as a result, the processing capacity can be improved.

Further, at the time of changing the reproduction mode, of the SFs stored in the buffer of the control device, only the SFs required after the change are taken out and transmitted, so that the SFs are read from the information storage device and transmitted. Since it is possible to change the reproduction mode without waiting for that, it is possible to change the video with a quick response to the reproduction mode change request from the user device.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a server device according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram of control devices 121 and 122 in the same embodiment.

FIG. 3 is a block configuration diagram of a sending control unit 206 in the embodiment.

FIG. 4 is a flow chart diagram illustrating an operation of a scheduled transmission time calculation unit 303 according to the first embodiment of this invention.

FIG. 5 is an actual transmission time calculation unit 304 in the embodiment.
Flowchart explaining the operation of

FIG. 6 is a block configuration diagram of a video providing unit 207 in the embodiment.

FIG. 7 is a diagram showing the relationship between the transmission timing interval, the information read request transmission interval, the SF reception interval, and the SF transmission interval to the user in the embodiment.

FIG. 8 is a diagram showing a message format of an information read request in the embodiment.

FIG. 9 is a diagram showing a message format of a packet having SF as an information element in the embodiment.

FIG. 10 is an information storage device 101 according to an embodiment of the present invention.
To 103 block diagram

FIG. 11 is an SF reading control unit 100 in the same embodiment.
4 is a flowchart for explaining the operation of FIG.

FIG. 12 is an image providing unit 2 according to the second embodiment of the present invention.
Block diagram of 07

FIG. 13 is a flow chart for explaining the operation of the SF editing unit 1203 in the same embodiment.

FIG. 14 is a flow chart for explaining the operation of a scheduled transmission time calculation unit 303 in the third embodiment of the present invention.

FIG. 15 is an actual transmission time calculation unit 30 in the embodiment.
4 is a flowchart for explaining the operation of FIG.

FIG. 16 is a transmission number management unit 20 according to the embodiment of the present invention.
Figure showing management items in 3

[Explanation of symbols]

 101 to 103 Information storage device 111 Switching device 121 to 122 Control device 131 to 136 User device 201 Request acceptance unit 202 Traffic amount management unit 203 Transmission number management unit 204 Transmission interval management unit 205 Delay limit value management unit 206 Transmission control unit 207 Video Providing unit 301 Sequence management unit 302 Clock 303 Scheduled transmission time calculation unit 304 Actual transmission time calculation unit 305 Delay limit value calculation unit 306 Actual transmission time and delay limit value management unit 307 Read request transmission unit 601 SF reception unit 602 SF Transmission time management unit 603 Clock 604 SF transmission unit 1001 Request information management unit 1002 Request reception unit 1003 Request information registration unit 1004 SF read control unit 1005 Disk 1006 Buffer memory 1007 SF transmission determination unit 1008 Discard processing unit 1009 SF transmitter 1201 SF receiver 1202 SF transmission time management unit 1203 SF editing unit 1204 SF transmission unit 1205 Clock

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 7/16 A // G06T 13/00

Claims (13)

[Claims] 1. A video data is divided into fixed-length segment files (SF), and one or a plurality of information storage devices storing the SFs and a plurality of control devices are connected to a switching device, and the control devices have , A single or a plurality of user devices are connected, and the control device sends to the information storage device an information read request requesting the reading of the SF, obtains the SF, and sends it to the user device. In the server device for transmitting a video stream as described above, each of the control devices limits the number of the information reading requests transmitted within a fixed time to a fixed value or less. 2. The control device, based on the reproduction speed of the video stream provided to the user device and the information amount per SF,
The time to send the information read request is determined, and the time to send the information read request should be sent so that the number of the information read requests sent within a certain time does not exceed a certain value. The server device according to claim 1, wherein the server device is set to a time or a time earlier than the time to be sent. 3. The information read request includes a delay limit value, which is an upper limit value of the time required to read the SF stored in the information storage device, and the information storage device reads the information. 2. The server device according to claim 1, wherein the reading of the requested SF is completed by the time the delay limit time elapses after receiving the request. 4. The information storage device permits transmission of SF to a switching device when a delay limit time has elapsed after receiving an information read request. The server device according to item 3. 5. The information storage device is set with a maximum read time, which is an upper limit value of the time required for reading the SF, and after the maximum read time from the time when the information read request arrives. 5. The server device according to claim 4, wherein the reading of the requested SF is completed by the time of. 6. When a reproduction mode change request such as reproduction from a user device, special reproduction such as double speed reproduction or triple speed reproduction, or normal reproduction is requested, a single or plural pieces of information are read out. 4. The server device according to claim 3, wherein the delay limit value of the request is temporarily set to a value smaller than the delay limit value of the normal information reading request and is transmitted. 7. The information read request includes a delay limit value which is an upper limit value of the time required to read the SF stored in the information storage device, and the control device sets the information storage device to When data other than video data that does not require real-time processing is stored, when requesting the reading of data, the delay limit set to a value larger than the delay limit value of the information reading request. A request for reading the data is sent together with a value, and the information storage device receives the request for reading the information or the request for reading the data, and after the time of the delay limit value, 2. The server device according to claim 1, wherein the reading of the SF or the data requested up to this point is completed. 8. A request for video reproduction from a user device, or special reproduction such as double speed reproduction or triple speed reproduction,
Immediately after the control device receives a request to change the playback mode such as normal playback, even if the number of information read requests sent within a certain time has reached a certain value, one or more information read The server device according to claim 1, wherein the server device sends a request. 9. The control device manages the number of information read requests to be sent within a fixed time by setting an upper limit value so as to be a fixed value or less for each reproduction speed of a video stream to be provided. The server device according to claim 1. 10. A control device is provided with a transmission timing for transmitting an information reading request at regular intervals, and the number of information reading requests transmitted at the transmission timing is controlled to be a certain value or less. Interval A of the transmission timing for transmitting the information read request for each stream
Is the integer part of the value C obtained by dividing the size of SF by the time interval of the transmission timing and the video reproduction speed,
For each of the intervals A, the information read request is transmitted the number of times of the value B obtained by adding 1 to the integer part of the value obtained by dividing the interval A by the fractional part of C, and after the next interval A, At the time, the information read request is not sent repeatedly, and when the number of SFs waiting to be sent to the user device exceeds a certain value, the information read request is sent. 10. The server device according to claim 9, wherein the server device is controlled not to be performed once. 11. A control device determines the time at which an information read request should be sent from the playback speed of the video stream provided to the user device and the amount of information per SF, and sends the information read request. The transmission timing is set at every reproduction time of one frame of the video, and the number of the information read requests to be transmitted at the transmission timing is controlled so as to be equal to or less than a certain value. If the number of transmissions exceeds a certain value, the information reading requests for the excess number are transmitted after delaying the reproduction time of one frame of the video, and when transmitting the video stream to the user device. The server device according to claim 1, wherein the server device again sends the video data of the already sent frame to the user device. 12. The control device determines the time at which the information read request should be sent from the playback speed of the video stream provided to the user device and the amount of information per SF, and sends the information read request. The transmission timing is provided at every reproduction time of one frame of the video, and the number of transmission of the information reading request at the transmission timing is controlled to be a fixed value or less, and at the timing of transmitting the information reading request, If the number of transmissions exceeds a certain value, the information reading requests of the number exceeding the predetermined number are transmitted after delaying the reproduction time of one frame of the video, and when transmitting the video stream to the user device. 3. A command for instructing to hold the transmitted video frame for a reproduction time of one frame is transmitted to the user device. The server device described. 13. Video data is divided into fixed-length segment files (SF), and one or more information storage devices storing the SFs and a plurality of control devices are connected to an exchange device, and the control devices have , A single or a plurality of user devices are connected, and the control device sends to the information storage device an information read request for requesting to read the SF, acquires the SF, and acquires the user device. In the server device transmitting the video stream to the device, the control device sends the information read request in advance within a range in which the exchange capability of the exchange device and the SF read capability of the information storage device are allowable. Then, after obtaining the SF and storing the SF in a buffer provided in the control device, the SF is stored as a video stream in the user device. When there is a request from the user device to change the reproduction mode such as special reproduction such as double speed reproduction or triple speed reproduction or normal reproduction, it is necessary after the reproduction mode is changed in the SF in the buffer. A server device, wherein only the SF is selected and the changed video stream is transmitted to the user device.