JP3193563B2 - Real-time data reading system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a real-time data reading system for storing real-time data such as audio and moving images, and reading and reproducing the stored data.

[0002]

2. Description of the Related Art In recent years, an AV server that stores real-time data such as audio and video on a hard disk such as a personal computer and a workstation, reads and reproduces audio and video data from another personal computer and a workstation, and an interactive television. Video on demand, in which video information is managed intensively as a service and multiple pieces of information are accessed simultaneously, has attracted attention (for example, Nikkei Communication 1993.2.15 No.144 pp.
38-55).

In order to realize these, it is necessary to read out real-time data by a time required for reproducing the stored real-time data. For example, reproduction of a standard moving image requires information of 30 frames per second.

[0004]

However, after requesting data reading and before receiving data,
A delay occurs such as a time for searching and reading from a hard disk or the like in which data is stored and a time for transferring data. This delay varies depending on the load such as the number of reproductions. Therefore, there arises a problem that data cannot be read by the time required for reproduction. Therefore, there is a problem that a large-capacity buffer memory must be provided in order to prevent the problem due to the fluctuation of the delay time.

As a method of storing one real-time data, a method of storing data in a plurality of places instead of storing in one place has been disclosed (for example, Tanaka, Shimojo, "Current state of moving image database technology and Future ”, IPSJ Advanced Database Symposium '9
3 Papers, December 1993, pp.55-62). However,
When data is stored by such a method, the delay time may differ depending on each storage location, and the data cannot be read out by the time required for reproduction, or the interval for receiving the read out data varies, causing transmission fluctuation. There is.

The present invention takes into consideration such a problem when reading conventional real-time data, and can read data by a time required for reproduction without increasing the buffer capacity for temporarily storing the read data. It is another object of the present invention to provide a real-time data reading system capable of suppressing variations in intervals at which data to be read is received and suppressing transmission fluctuations.

[0007]

According to a first aspect of the present invention, there is provided one or a plurality of data storage units for dividing and storing data such as moving images and audio in units, In a real-time data reading system including one or more data reading control units that issue a data reading request and output the read data at a predetermined timing, the data reading control unit transmits data to a data storage unit. Read request sending means for making a read request, data receiving means for receiving data read by the read request, and delay managing means for measuring and managing a delay time from when the read request is made to when the data is received The read request sending means is controlled by the scheduled time and delay management means to output the received data at a predetermined timing. Based on the delay time, a real-time data readout system for reading request.

According to a third aspect of the present invention, there is provided one or a plurality of data storage units for storing data such as moving images and audio data in units of one or more units, and making a data read request to the data storage units. In a real-time data reading system including one or more data reading control units that output read data at a predetermined timing, the data storage unit estimates a delay time generated based on a predetermined delay factor, A delay information transmitting unit that transmits delay information of the estimated delay time to the data read control unit, wherein the data read control unit performs a data read request to the data storage unit; A data receiving means for receiving the data read by the read request, and receiving the delay information transmitted from the delay information transmitting unit; A delay information reception management unit for setting a delay time of the delay information, wherein the read request sending unit is configured to output the received data at a predetermined timing based on a scheduled time to output the received data at a predetermined timing and the delay time set in the delay information reception management unit , A real-time data read system that issues a read request.

[0009]

According to a first aspect of the present invention, a read request sending unit sends a read request to a data storage unit based on a scheduled time at which received data is to be output at a predetermined timing and a delay time managed by the delay management unit. The delay management means measures and manages the delay time from when the read request is made to when the data receiving means receives the data.

According to a third aspect of the present invention, the delay information transmitting section of the data storage section estimates a delay time generated based on a predetermined delay factor, and sends the delay information of the estimated delay time to the data read control section. The delay information reception management unit of the data read control unit receives the delay information transmitted from the delay information transmission unit, sets a delay time of the received delay information, and the read request transmission unit transmits the received data to the reception unit. A read request is issued based on the scheduled time to be output at a predetermined timing and the delay time set in the delay information reception management unit.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing embodiments thereof. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of a moving image data reading system according to Embodiment 1 of the present invention. In FIG. 1, reference numerals 1a, 1b, and 1c denote moving image storage units, which are data storage units, and record data of a single or a plurality of moving images in units of frames. 2a,
Reference numeral 2b denotes a moving image data read control unit which is a data read control unit. The moving image frame data is stored on the basis of moving image sequence data in which address information in which the moving image frame data is stored is recorded in accordance with the moving image frame order. And read it out. Reference numeral 3 denotes a data transmission path for performing data transmission between the moving image storage units 1a, 1b, 1c and the moving image data read control units 2a, 2b.

FIG. 2 shows the internal structure of the moving image data read control unit 2a shown in FIG. 1 (the same applies to 2b).
FIG. 4 is a block diagram showing the configuration of FIG. In FIG. 2, 4
Is a sequence data storage unit which stores sequence data of a moving image to be reproduced. Reference numeral 5 denotes a read request transmitting unit which is a read request transmitting unit, and transmits a frame data read request to the moving image storage units 1a, 1b, and 1c according to the sequence data in the sequence data storage unit 4. Reference numeral 6 denotes a delay management unit serving as a delay management unit, which measures and manages a delay time from when a frame data read request is sent to when frame data is actually received. Reference numeral 7 denotes a frame data receiving unit serving as a data receiving unit, which receives and temporarily stores frame data from the moving image storage units 1a, 1b, and 1c.

Actually, in addition to the above, various other components such as a function of reproducing a moving image from frame data of a moving image, a function of performing an interface process with a user, and a function of processing a communication interface with the data transmission path 3 are required. But,
The description is omitted because it is not the main feature of the present invention.

Next, the operation of the moving picture data reading system configured as described above will be described with reference to the drawings.

FIG. 3 is a diagram showing an example of sequence data stored in the sequence data storage unit 4. In this example, the sequence number of the moving image, the ID of the moving image storage unit storing the frame data, and the file ID are managed.

FIG. 4 is a diagram showing an example of a control sequence of the moving image data read control unit 2a and the moving image storage units 1a, 1b, 1c. In this example, the moving image data read control unit 2a specifies the ID of the moving image storage unit and the file ID to the moving image storage units 1a, 1b, and 1c, and sends a “read request”.
It indicates that the requested "frame data" is received after a delay D1 or D2 as a response thereto. Also,
The received frame data is periodically output to the outside.

Now, when a user requests a reproduction of a moving image, the read request transmitting unit 5 transmits the read request to the sequence data storage unit 4.
A "read request" is transmitted to the moving image storage units 1a, 1b, and 1c through the data transmission path 3 in accordance with the sequence data. The transmission timing is set so as to be in time for the time required for the requested frame data and the required time calculated from the delay time managed by the delay management unit 6. Next, the moving image storage units 1a, 1b, and 1c receive the "read request" and transmit frame data corresponding to the "read request" to the moving image data read control unit 2a. Then, the frame data receiving unit 7 receives the frame data and stores the frame data until the frame data is needed for reproducing the moving image. At this time, the delay management unit 6 measures a delay from sending out the “read request” to receiving the frame data, and sets a delay time for the next “read request” to be transmitted.

In the example shown in FIG. 4, the moving image frame data A1
When reading 01, the delay managed by the delay management unit 6 is D1, and a “read request” of A101 is transmitted before the delay D1 from the time when the A101 of the frame data is required. Next, A101 of the frame data corresponding to the read request
And the delay time from sending the "read request" is D1
If so, the delay management unit 6 manages the delay as D1 because there is no change in the delay. Similarly, for the A102 of the frame data that is required next, the “read request” of the A102 before the delay D1 from the time when the A102 of the frame data becomes necessary
Is sent.

Thereafter, if the delay varies due to an increase in the load on the system or the like, the delay management unit 6 sets a delay time from when the read request is sent to when the frame data corresponding to the read request is received. Is measured differently from the delay D1, and the delay management unit 6 changes the managed delay time value to the newly measured delay time value. At this time, if there is a delay fluctuation until the next read request is transmitted until the frame data is received, in other words, until the new delay time is measured, the frame data cannot be output in time for the frame data. Is discarded, but the next read request is sent out with a new delay. For example, as shown in FIG. 4, if the delay D1 is changed to the delay D2 before reading the frame data A1001, when the frame data A1001 is read, the delay managed by the delay management unit 6 becomes D2. A “read request” of A1001 is transmitted before the delay D2 from the point in time when the A1001 of the frame data is required. Then, the delay D2 from the time when the frame data A1002 becomes necessary
A “read request” of A1002 is transmitted earlier.

As described above, the delay time from when the read request is made to when the frame data is received is measured and managed, and the read request is transmitted in consideration of the delay time, thereby temporarily storing the frame data. The frame data can be prepared by the required time without increasing the buffer capacity.

In the first embodiment, the moving image data is divided on a frame basis. However, it is also possible to divide a plurality of frames at a time or to further divide one frame.

In the first embodiment, the moving image storage unit is
Although the number of the moving image data read control units is two, the number is not limited to this, and the number can be increased or decreased.

In the first embodiment, the moving image sequence data is stored in the moving image data readout control unit. Alternatively, the sequence data may be obtained from the outside as needed.

In the first embodiment, the "read request" is transmitted so as to receive the frame data immediately before the frame data is required. However, the present invention is not limited to this, and the buffer for temporarily storing the frame data may be used. It is also possible to provide a sufficient capacity so as to receive one or a plurality of frames earlier. In this case, it is possible to prevent data from being discarded due to a change in delay. (Embodiment 2) Next, a moving image data reading system according to Embodiment 2 of the present invention will be described.

A block diagram showing the configuration of the moving image data reading system according to the second embodiment of the present invention is the same as FIG. 1 of the first embodiment. A block diagram showing the internal configuration of the moving image data readout control units 2a and 2b of the second embodiment is the same as that of FIG. 2 of the first embodiment. However, the delay management unit 6 manages the delay time for each of the moving image storage units 1a, 1b, and 1c, and the read request transmission unit 5 transmits a "read request" based on the delay time of each moving image storage unit.

Actually, other various components are required, such as a function of converting a moving image into frame data, a function of performing an interface process with a user, and a function of processing a communication interface with the data transmission path 3. The description is omitted because it is not the main feature of the present invention.

Next, the operation of the moving picture data reading system configured as described above will be described with reference to the drawings.

In the second embodiment, an example of the sequence data stored in the sequence data storage section 4 is the same as that in FIG. 3 of the first embodiment.

FIG. 5 is a diagram showing an example of the delay information managed by the delay management unit 6. As shown in FIG. 5, in this example, the delays Da, Db, and Dc are managed corresponding to the moving image storage units 1a, 1b, and 1c, respectively.

FIG. 6 is a diagram showing an example of a control sequence of the moving image data read control unit 2a and the moving image storage units 1a, 1b, 1c. In this example, the moving image data read control unit 2a specifies the ID of the moving image storage unit and the file ID to the moving image storage units 1a, 1b, and 1c, and sends a “read request”.
It indicates that the requested "frame data" is received after a delay Da, Db, Dc as a response thereto. The received frame data is periodically output to the outside.

Now, when a user requests a reproduction of a moving image, the read request transmitting unit 5 transmits the read request to the sequence data storage unit 4.
A "read request" is transmitted to the moving image storage units 1a, 1b, and 1c through the data transmission path 3 in accordance with the sequence data. The transmission is performed in such a manner that the time required for the requested frame data and the required time calculated from the delay time of each moving image storage unit managed by the delay management unit 6 are sufficient. Next, the moving image storage units 1a, 1b, 1
c receives the “read request” and transmits the corresponding frame data to the moving image data read control unit 2a. Then, the frame data receiving unit 7 receives the frame data and stores the frame data until the frame data is needed for reproducing the moving image. The delay management unit 6 measures the delay from sending the “read request” to receiving the frame data, and updates the delay time of the corresponding moving image storage unit.

In the example of FIG. 6, A1 of the frame data of the moving image
01 is read from the moving image storage unit 1a, the delay management unit 6
A1 before the delay Da from the point in time when the delay of the moving image storage unit 1a managed by
A "read request" of 01 is sent. Then, the moving image storage unit 1b
Since the delay Db of the frame data is large and it is not enough to send the frame data A102 "read request" after receiving the frame data A101, the frame data A102
Send a "read request". After that, A1 of the frame data
01 and frame data A102. As for the frame data A103, since the delay Dc of the moving image storage unit 1c is small, a “read request” is transmitted after receiving the frame data A102, and the frame data A103 is received.

Thereafter, when there is a change in the delay time of each moving image storage unit measured by the delay management unit 6, the timing of the read request is calculated using the new measured delay time.

As described above, the delay time from when the read request is made to when the frame data is received is measured and managed for each moving image storage unit, and the request is transmitted in consideration of the delay time, whereby the frame data is transmitted. The frame data can be prepared by the required time without increasing the buffer capacity for temporarily storing. Further, it is possible to reduce the transmission fluctuation on the data transmission path by making the interval for receiving the frame data constant.

Although the moving image data is divided in frame units in the second embodiment, it is also possible to divide a plurality of frames at a time or to further divide one frame.

In the second embodiment, the moving image storage unit is
Although the number of the moving image data read control units is two, the number is not limited to this, and the number can be increased or decreased.

In the second embodiment, the moving image sequence data is stored in the moving image data read control unit. Alternatively, the sequence data may be obtained from the outside as necessary.

In the second embodiment, the "read request" is transmitted so as to receive the frame data immediately before the frame data is required. However, the buffer capacity for temporarily storing the frame data has a margin. Alternatively, it may be configured to receive one or a plurality of frames earlier. In this case, it is possible to prevent data from being discarded due to a change in delay. (Embodiment 3) Next, a moving image data reading system according to Embodiment 3 of the present invention will be described.

A block diagram showing the configuration of the moving image data reading system of the third embodiment is the same as that of FIG. 1 of the first embodiment.

FIG. 7 shows a moving image data read control unit 2a.
It is the block diagram shown about 2b of internal structures. FIG.
In the figure, reference numeral 8 denotes a sequence data storage unit which stores sequence data of a moving image to be reproduced. Reference numeral 9 denotes a read request transmitting unit that sends a frame data read request to the moving image storage units 1a, 1b, and 1c in accordance with the sequence data in the sequence data storage unit 8. 10
Denotes a delay information reception management unit, and the moving image storage units 1a, 1
b, 1c, and manages the delay time used when transmitting a frame data read request. 11
Denotes a frame data receiving unit, and the moving image storage units 1a, 1
b and 1c to receive and temporarily store the frame data.

FIG. 8 is a block diagram showing the internal configuration of the moving image storage units 1a, 1b, and 1c. Reference numeral 12 denotes a moving image management unit which stores and manages frame data of a moving image. A read request receiving unit 13 receives a read request for frame data and reads the frame data from the moving image management unit 12. 14 is a delay information transmitting unit,
The delay time is estimated based on the number of read requests accumulated in the read request receiving unit, and the moving image data read control unit 2
The delay information of the estimated delay time is transmitted to a and 2b. 1
Reference numeral 5 denotes a frame data transmitting unit which transmits the frame data read from the moving image management unit 12 to the moving image data read control units 2a and 2b.

Actually, other various components are required, such as a function of converting a moving image into frame data, a function of performing an interface process with a user, and a function of processing a communication interface with the data transmission path 3. The description is omitted because it is not the main feature of the present invention.

Next, the operation of the moving image data reading system configured as described above will be described with reference to the drawings.

In the third embodiment, an example of the sequence data stored in the sequence data storage section 8 is the same as that of the first embodiment shown in FIG. An example of the delay information managed by the delay management unit 6 is the same as that in FIG. 5 of the second embodiment.

FIG. 9 is a diagram showing an example of a control sequence of the moving image data read control unit 2a and the moving image storage units 1a, 1b, 1c. In this example, the moving image data read control unit 2a specifies the ID of the moving image storage unit and the file ID to the moving image storage units 1a, 1b, and 1c, and sends a “read request”.
In response to the request, it indicates that the requested “frame data” is received after the delays Da, Db, Dc, and Dc ′ (Dc ′ indicates the delay after the change in the moving image storage unit 1c). The received frame data is periodically output to the outside. Also, a “delay notification” to which a new delay Dc ′ is added is transmitted from the moving image storage unit 1c to the moving image data read control unit 2a.

Now, when a user requests a reproduction of a moving image, the read request transmitting section 9 transmits the sequence data to the sequence data storage section 8.
A "read request" is transmitted to the moving image storage units 1a, 1b, and 1c through the data transmission path 3 in accordance with the sequence data. The transmission is performed in such a way that the time required for the requested frame data and the required time calculated from the delay time of each moving image storage unit managed by the delay information reception management unit 10 are sufficient. Read request receiving unit 1
3 receives the “read request”, reads the corresponding frame data from the moving image management unit 12, and the frame data transmission unit 15 transmits the read frame data to the frame data reception unit 11. The frame data receiving unit 11 receives the frame data and stores the frame data until the frame data is needed for reproducing the moving image. Delay information transmission unit 14
Indicates a “read request” stored in the read request receiving unit 13
The delay time required for reading the frame data is calculated (estimated) from the number, and if there is a change in the delay time, a “delay notification” is transmitted to the delay information reception management unit 10. The delay information reception management unit 10 manages the delay time included in the received “delay notification”.

In the example of FIG. 9, the moving image data read control unit 2a reads the moving image frame data A101, A102, and A103 from the moving image storage units 1a, 1b, and 1c from the time when each frame data is needed. A “read request” is sent before the delays Da, Db, and Dc of the moving image storage units 1a, 1b, and 1c managed by the delay management unit 6. After that, frame data corresponding to each read request is received. Video storage unit 1
c, a “read request” is sent to the read request receiving unit 13.
When the delay calculated in the moving image accumulating unit 1c fluctuates after the read request is received, the delay information transmitting unit 14 sends a “delay notification” including the new delay time Dc ′ to the moving image data reading control unit. 2a. After that, when reading out the frame data A104 and A105 from the moving image accumulating units 1a and 1b, a "reading request" is transmitted using the same delays Da and Db as before. On the other hand, frame data A106
Is read from the moving image storage unit 1c, a "read request" is transmitted using the delay Dc 'notified previously.

As described above, the delay required for reading the frame data is determined by each moving image storage unit side, notified to the moving image data read control unit, and the request is transmitted in consideration of the delay, thereby temporarily storing the frame data. The frame data can be prepared by the required time without increasing the buffer capacity for temporary storage. Further, it is possible to reduce the transmission fluctuation on the data transmission path by making the interval for receiving the frame data constant. Further, it is possible to know in advance the fluctuation of the delay required for reading.

In the third embodiment, the moving image data is divided on a frame basis. However, it is also possible to divide a plurality of frames collectively or to further divide one frame.

In the third embodiment, the moving image storage unit is
Although the number of the moving image data read control units is two, the number is not limited to this, and the number can be increased or decreased.

In the third embodiment, the moving image sequence data is stored in the moving image data read control unit. Alternatively, the sequence data may be obtained from the outside as needed.

In the third embodiment, the "read request" is transmitted so as to receive the frame data immediately before the frame data is required. However, the present invention is not limited to this, and the buffer for temporarily storing the frame data may be used. A configuration may be adopted in which a sufficient capacity is provided so that one or a plurality of frames can be received earlier. In this case, it is possible to prevent data from being discarded due to a change in delay.

In the third embodiment, the predetermined factor is determined based on the number of read requests accumulated in the moving image storage unit. However, the present invention is not limited to this. Other relevant factors may be used. Alternatively, the determination may be performed including these.

[0054]

As is apparent from the above description, according to the present invention, data can be read by the time required for reproduction, and the data to be read can be read without increasing the buffer capacity for temporarily storing the read data. It has the advantage that variations in receiving intervals can be suppressed and transmission fluctuations can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a real-time data reading system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating an internal configuration of a moving image data read control unit according to the first embodiment.

FIG. 3 is a diagram illustrating an example of sequence data stored in a sequence data storage unit according to the first embodiment.

FIG. 4 is a diagram illustrating an example of a control sequence of a moving image data read control unit and a moving image storage unit according to the first embodiment.

FIG. 5 is a diagram illustrating an example of delay information managed by a delay management unit according to the second embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of a control sequence of a moving image data read control unit and a moving image storage unit according to the second embodiment.

FIG. 7 is a block diagram illustrating an internal configuration of a moving image data read control unit according to a third embodiment of the present invention.

FIG. 8 is a block diagram illustrating an internal configuration of a moving image storage unit according to the third embodiment.

FIG. 9 is a diagram illustrating an example of a control sequence of a moving image data read control unit and a moving image storage unit according to the third embodiment.

[Explanation of symbols]

 1a, 1b, 1c Moving image storage unit 2a, 2b Moving image data read control unit 3 Data transmission path 4 Sequence data storage unit 5 Read request transmission unit 6 Delay management unit 8 Sequence data storage unit 9 Read request transmission unit 10 Delay information reception management unit 12 Video management unit 13 Read request reception unit 14 Delay information transmission unit

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04N 7/10 H04N ^7/ 14-7/173 H04N ^7/ 20-7/22

Claims (6)

(57) [Claims] 1. One or a plurality of data storage units for storing data such as moving images, audio data, etc. in units of units, making a data read request to the data storage unit, and reading the read data A real-time data readout system comprising one or more data readout control units for outputting at the timing of (i), wherein the data readout control unit comprises: a read request sending unit for making a data readout request to the data storage unit; Data receiving means for receiving data read by the read request,
A delay management unit that measures and manages a delay time from when the read request is made to when the data is received, wherein the read request sending unit is configured to output the received data at the predetermined timing, and A real-time data read system, wherein a read request is issued based on a delay time managed by a delay management unit. 2. The real-time data reading system according to claim 1, wherein said read request sending means issues a read request based on said scheduled time and at least a delay time measured immediately before. 3. One or a plurality of data storage units for dividing and storing data such as moving images and audio in units, and requesting data reading from the data storage unit, and reading the read data in a predetermined manner. A real-time data readout system including one or more data readout control units that output at the timing of:
A delay information transmitting unit configured to estimate a delay time generated based on a predetermined delay factor and transmit delay information of the estimated delay time to the data read control unit; A read request sending unit for making a data read request to the unit, a data receiving unit for receiving the data read by the read request, and receiving the delay information transmitted from the delay information transmitting unit. A delay information reception management unit for setting a delay time of the delayed information, wherein the read request sending unit is configured to set a scheduled time at which received data should be output at the predetermined timing and the delay information reception management unit. A real-time data read system, wherein a read request is issued based on a delay time. 4. The real-time data reading system according to claim 1, wherein the setting of the delay time is performed for each of the data storage units. 5. The delay information transmitting section of a data storage section,
4. The real-time data read system according to claim 3, wherein the delay information is transmitted to the data read control unit only when there is a change in the estimated delay time. 6. The real-time data reading system according to claim 3, wherein the predetermined delay factor is the number of read requests existing in the data storage unit.