JP3476313B2 - Time continuous media server system with variable bit rate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention accumulates a large number of variable-rate time-continuous media information, transmits requested time-continuous media information in response to a request from a terminal device, and enables reproduction in the terminal device. The present invention relates to a time continuous media server system, and more particularly to a time continuous media server system capable of handling a variable bit rate time continuous media and suppressing an increase in processing load on the server.

[0002]

2. Description of the Related Art Conventionally, time continuous media server systems have dealt with fixed bit rate time continuous media.
For example, as described in Japanese Patent Laid-Open No. 4-269087, it is realized by reading from the disk at a constant time interval according to the bit rate.

FIG. 4 shows a bit rate control and multiplexing method of a conventional time continuous media server system, in which time slot allocation intervals, that is, cycles are determined according to the encoding bit rate.

As described above, this method is suitable for the bit rate control and the multiplexing when the fixed same coding bit rate is handled.

[0005]

However, in the conventional time continuous media server system, since the time slot is assigned to the terminal in advance, the transmission bit rate of the time continuous media that can be handled is fixed. Further, conventionally, the recognition of the encoding bit rate is performed by reading the time continuous media,
This was done before the transmission process, and the time slot interval and cycle were actually set in advance, but since the variable bit rate fluctuates over time, the coding bit rate is recognized in advance and the time slot interval and cycle are set. Cannot be uniquely determined.

Therefore, it is necessary to dynamically recognize the coding bit rate and to process the variable bit rate. The coding bit rate information can be known by reading the coding bit rate information described in the time continuous medium. However, since the process of reading this information needs to be performed at each interval of the change points of the encoding bit rate, compared to the case where this process is not performed when the fixed bit rate was previously recognized, the server does not. This load becomes large.

An object of the present invention is to make it possible to handle a time-continuous medium having a variable bit rate and to suppress an increase in the processing load on the server due to the support of the variable bit rate.

[0008]

In order to solve this problem, the present invention provides a time continuous media server which provides variable bit rate compression-encoded time continuous information, and information provided by the time continuous media server. In a time continuous media server system comprising a terminal for decompressing, decoding and playing back, the time continuous media server accepts a request for information provision from the terminal, and reproduces the bit rate time change information of the requested time continuous information and the requested information. A request management unit that outputs management information composed of position information, and an average bit rate for a fixed time interval is calculated from the management information, and the amount of data obtained from this average bit rate and the fixed time interval.
And a bit rate control means for outputting the minimum number of blocks exceeding the number of read requests as the number of read requests, and creating the required number of addresses designating the blocks to be read from the management information based on the type of time continuous information and the reproduction position. A request editing unit that specifies a block time-out time from the number of requests, a request order editing unit that sorts the addresses that specify the blocks to be read in the order of the block time-out time, and inputs the time slots in this order, and the time slot. The time-sequential media transmission control means for outputting the information read by the disk device, which stores the time-sequential information in block units in a distributed manner, to each requesting terminal.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

(First Embodiment) FIG. 1 shows the configuration of a video server system compatible with variable bit rate video coding. The time-series media server MS that provides the variable bit rate compression-encoded time-series information, and the terminal units TG1 to TGn that receive the variable bit rate compression-encoded time-series information, the media server MS comprising: Variable bit rate disk device 11-1m that stores encoded video information with audio distributed in blocks of fixed size, and disk with audio information video information to be read for each terminal using time slots A multiple access control device (MAC) 30 that notifies the device, a request management unit 36 that receives video information with audio from each terminal, manages server internal resources, and manages request contents of the terminal units TG1 to TGn, and each terminal. Of the video information with audio to be read based on the content of the request and the number of blocks specified by the bit rate control unit. The request editing unit 35 for editing the address of the clock, the time continuous media transmission control device (MTC) 22 for outputting the video information with audio reproduced by the disk device 11 to 1 m to the destination terminal, and the time slot. A switch 21 for transmitting a block read request to the disk devices 11-1m and outputting the video information with audio read by the disk devices 11-1m to the MTC 22.

Further, the multiple access control device (MAC) 30
Is a time slot that manages the number of blocks of video information with audio input to time slots Q1 to Qr34 that conveys the request from each terminal to the disk devices 11 to 1m, and controls which time slot is used. Management Department
32 and the bit rate time change information storage unit (BTC) that stores the bit rate time change information of video information with audio.
S) 38, the timing specified by the time slot management unit 32, and the bit rate control unit 33 that calculates the average bit rate for each fixed time for each terminal based on the information accumulated in the BTCS38, and the block obtained from the BTCS38. Or the request sequence editing unit 37 that rearranges the order of inputting the address of the block of video information with audio into the time slot according to the priority time of the block of video information with audio specified by the request editing unit 35,
The switch 31 is provided with a switch 31 for switching the time slots Q1 to Qr output to the switch 21 at fixed time intervals.

On the other hand, the terminal units TG1 to TGn include normal buffer memories 41 to 4n for temporarily storing the received information and decompressors 51 to 5n for decompressing and decoding the accumulated time continuous media information.
And a media display unit 61 that displays the decompressed and decoded information.
With ~ 6n.

The operation of the time continuous media server system configured as described above will be described below.

In this time-continuous media server system, the terminal units TG1 to TGn request the provision of time-continuous media information by designating the type of information and the reproduction position. In response to this, the multiple access control device MA of the time continuous media server MS
The C30 cooperates with the request management unit 36 and the request editing unit 35 to request the disk devices 11 to 1m for blocks to be read one after another using the time slots Q1 to Qr34.

The disk devices 11-1m sequentially read out the blocks requested by the multiple access control device MAC30,
Outputs to the time continuous media transmission controller MTC22,
The bit-rate control unit 33 distributes the compression-encoded block of audio-added video information to each terminal unit TG1 to TGn.
Will be transmitted at the bit rate specified by. Each terminal unit TG1 to TGn
Then, the expander 51-
After being expanded by 5n, the images are sequentially displayed on the display units 61 to 6n.

At this time, compression-encoded reproduction information needs to be delivered to each of the terminal units TG1 to TGn so that video and audio when decompressed and reproduced are not interrupted. In order to satisfy this requirement, the bit rate control unit 33 controls the transmission rate to the terminal units TG1 to TGn and the block read rate from the disk devices 11 to 1m. The bit rate control unit 33 of the multiple access control device MAC30 calculates an average bit rate at constant time intervals based on the bit rate time change information stored in the bit rate time change information storage unit 38, and lowers this average bit rate. In addition to performing the operation of setting the minimum number of blocks that is not present as the number of read requests, the information that is read above the average bit rate is reflected as carryover data when the number of read requests is calculated next. Time Continuous Media Transmission Controller MTC22
The average bit rate is used to specify the transmission rate of the read information.

The bit rate time change information stored in the bit rate time change information storage section 38 and the operation of the bit rate control section 33 will be described in detail with reference to FIG. As shown in FIG. 2, as the bit rate time change information,
Information type, coding bit rate and playback start time,
It is described in units where the coding bit rate changes. The unit of time when the coding bit rate changes is not constant,
It also depends on the type of information. Therefore, it is expected that a considerable load will be applied to control according to the change of the bit rate.

The bit rate control unit 33 is not a unit of a change in the encoding bit rate, but an average bit rate (T) of a constant time interval (T) in order to enable control at a constant time interval set in the server. BR) is calculated. This average bit rate is used for transmission rate control, and control is also performed at time intervals T. In controlling the read rate of a fixed-length block (block size = BB), the minimum number of blocks (BN) that exceeds the data amount obtained from the time interval T and the average bit rate (BR) is input to the request editing unit 35. . In the next cycle, the read rate is calculated by reflecting the extra read data amount in the previous cycle. The number of read requests (the number of blocks) in a certain cycle Ti is BN
i, the average bit rate is BRi, and the function representing the time change of the bit rate is f (t), BNi x BB > = (average bit rate in period Ti) x T- (excessive reading in period Ti-1) Data amount) = BRi × T− (BN _i−1 × BB− BRi−1 × T ). The formula for calculating the average bit rate BRi is also shown in FIG. The cycle T is determined by the time slot management unit 32, and the operation start timing is input to the bit rate control unit 33 at intervals of the cycle T.

Further, the request order editing unit 37 is provided with a request editing unit 35.
The addresses that specify the blocks to be read that are input by are rearranged according to the time until the time limit at which video and audio can be transmitted without interruption and the priority of blocks,
Input to a time slot where video and audio can be transmitted without interruption. The time slot management unit 32 sets the allowable range of the number of addresses that specify the blocks to be read, which are input to the time slot, and the processing contents when the allowable range is exceeded, and when the allowable range is exceeded. For, the processing according to the setting content is executed, and the executed content is recorded as a log. By disposing or forcing the processing contents, the bandwidth of the block read network,
You can select the setting that is suitable for the type.

The disk devices 11 to 1m, to which the read request is transmitted by the time slot, read only the designated block of the audio-video information. As a result, the number of blocks commensurate with the average bit rate at a fixed time interval is sequentially read from the disk devices 11 to 1m.

Now, assuming that the user uses the terminal unit TG1 to request provision of time continuous media information,
The operation of this system will be described. The user is the terminal unit TG1
Use to enter the type of time continuous media information you want and the request for its playback position. This request is
Input to the request management unit 36 of the time continuous media server MS, and from the request management unit 36, the request editing unit 35, the bit rate control unit 33 of the MAC 30, the bit rate time change information storage unit, and the MTC 22.
Sent to. At this time, the request management unit 36 creates management information (LMI) that links the bit position time change information of the requested time continuous media information and the reproduction position information with the terminal unit TG1.

Upon receiving this request, the bit rate control unit 33 calculates the average bit rate for a fixed time interval with reference to the management information LMI in accordance with the time interval designated by the time slot management unit 32, and the average bit rate is calculated. The minimum number of blocks not less than is input to the request editing unit 35 as the number of read requests. When the number of read requests is specified above the average bit rate, the operation to reflect it as carryover data when calculating the average bit rate is performed. By inputting, the transmission rate is instructed.

The request editing unit 35 that has received the number of read requests
Creates the addresses for the requested number of blocks that specify the blocks to be read based on the type and playback position of the time-continuous media information of the management information LMI, specifies the timeout time of the blocks, and inputs them to the request sequence editing unit 37.

The request sequence editing unit 37 rearranges the addresses designating the blocks to be read in the order of the time-out time of the blocks and inputs the addresses in this order in the time slots. At this time, referring to the time-out time, in the next time slot, a block that cannot be processed in time is input beyond the allowable range. The time slot to be input is
Designated by the time slot management unit 32.

The time slot management unit 32 switches the time slots Q1 to Qr34 at regular time intervals and sequentially outputs the addresses, which are input to the time slots and which designate the blocks to be read, to the switch 31, and these addresses are sequentially output. It is sent to the switch 21. Addresses that exceed the allowable range will be
Run. As the processing content, the system administrator can select to discard or ignore.

Based on the received address, the switch 21 sequentially sends to the disk devices 11-1m designated by the address. The disk device reads the specified blocks of the time continuous media information to be stored in the requested order,
The read information is time continuous media transmission control device MTC22
Output to. Based on the request received from the request management unit 36 and the average bit rate instruction received from the bit rate control unit 33, the MTC 22 outputs the read time continuation information to the destination terminal unit.

As described above, the output media information is temporarily stored in the buffer memories 41 to 4n of the terminal units TG1 to TGn, then expanded by the expanders 51 to 5n, and displayed on the media display units 61 to 6n. Will be played.

As described above, in the media server system according to the first embodiment, it is possible to handle the variable bit rate time continuous information that is compression-encoded, and the encoding described in the variable bit rate time continuous information is performed. Since the bit rate information is not directly handled, it is possible to suppress an increase in the server processing load associated with the variable bit rate support.

In addition, the allowable range of the number of addresses that can be input to the time slot is changed according to the fluctuation width of the bit rate, and the load on the switch is changed due to the expansion of the system. You can set the handling of the number of addresses that specify different blocks, so you can maximize the performance according to the environment.

(Second Embodiment) FIG. 3 shows a plurality of servers described in the first embodiment, servers providing fixed rate time continuous information, or servers providing non-time continuous information. Shows a system configuration connected to a single network, variable bit rate time continuous media server VMS1 ~ VMSl, fixed bit rate time continuous media server FMS1 ~ FMSm, non-time continuous media server NMS1
~ NMSn, terminal units TL1 to TLr receiving time continuous information or non-time continuous information sent from the server, and a network monitoring device NOV for monitoring the bandwidth used by the network
Consisting of a variable bit rate time continuous media server VM
S1 to VMSl are different from the server of the first embodiment,
Using the bit rate time change information, calculate the total average bit rate of the terminals before output, and use the network monitoring device.
A bit rate variation management unit 39 that notifies the NOV is added. Other configurations are the same as those in FIG.

The operation of the variable bit rate continuous time media servers VMS1 to VMSl will be described.

The operation until the terminal units TL1 to TLr receive the provision of the variable bit rate time continuous medium is the same as the contents described in the first embodiment. Independent of this behavior, the variable bit rate time continuous media server VMS1 ~
The VMSl bit rate fluctuation management unit 39 notifies the network monitoring device NOV of the total average bit rate of the server output data at a constant time interval based on the average bit rate calculated by the bit rate control unit 33. Upon receiving this notification,
The network monitoring device NOV predicts future network conditions and limits or expands the output of the non-time continuous media server. Further, the delay time when newly outputting the time-continuous media information is controlled.

As described above, in this embodiment, since the bit rate before the server output can be notified to the network monitoring device NOV in advance, it becomes possible to predict the state of the network, avoid the overload state, and free up. It is possible to effectively use the band.

[0034]

As described above, the time continuous media server system of the present invention makes it possible to handle compression-coded variable bit rate time continuous information, and increases the server processing load accompanying the variable bit rate. Can be suppressed. Further, it is possible to predict the network state of the network monitoring device, and thereby avoid the overloaded state of the network and effectively use the vacant band.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a time continuous media server system according to a first embodiment of the present invention,

FIG. 2 is a diagram for explaining an average bit rate calculation method of the time continuous media server system;

FIG. 3 is a block diagram showing a network configuration according to a second embodiment of the present invention,

FIG. 4 is a block diagram showing a configuration of a conventional constant bit rate media server system.

[Explanation of symbols]

MS media server Q1-Qr time slots TG1 to TGn Terminal section 11-1m disk unit 21, 31 switch 22 hours continuous media transmission controller 32 Time slot management section 33 Bit rate controller 35 Request Editor 36 Requirements Management Department 37 Request Sequence Editor 38 Bit rate time change information storage unit 39 Bit rate fluctuation management section 41 to 4n buffer memory 51-5n expander 61 to 6n Media display

Claims (2)

(57) [Claims] 1. A time-sequential media server comprising a time-sequential media server which provides time-sequential information which is variable bit rate compression coded, and a terminal which decompresses and reproduces the information provided by the time-sequential media server. In the system, the time continuous media server receives a request for information provision from the terminal, and outputs request management information composed of bit rate time change information of the requested time continuous information and reproduction position information, and Calculate the average bit rate for a certain time interval from the management information, and then use this average bit rate.
And a bit rate control means for outputting the minimum number of blocks exceeding the data amount obtained from a fixed time interval as the number of read requests, and an address designating a block to be read based on the type of the time continuation information and the reproduction position from the management information. A request editing unit that creates the requested number of times and that specifies the timeout time of the block from the number of read requests and an address that specifies the block to be read are rearranged in the order of the timeout time of the block, and a request to input to the time slot in this order. An order editing means and a time continuous media transmission control means for outputting the information read out by the disk device which dispersively accumulates the time continuous information in block units by using the time slot to each requesting terminal. A variable bit rate compatible continuous time feature characterized in that A server system. 2. A continuous-time media information is a variable bit-rate time continuous media server system of claim 1, wherein a is composed of audio with video information, a variable bit rate and the pair.