JP3228283B2 - Data recording / reproducing apparatus and data recording / reproducing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data recording / reproducing apparatus and a data recording / reproducing method for reproducing video data or the like in response to a request from a requester.

[0002]

In accordance with a plurality of optionally video signal transmission request from the Prior Art plurality of requesters, in reproducing the video signal, each requester H ₁ as shown in FIG. 15, H ₂ ··· H _n Dedicated playback devices, for example, video tape recorders R ₁ , R _2.
· The R _n are prepared, there are individual requester H _1, H ₂ ··· H monitor device M ₁ for _n, M ₂ ... M _n method for supplying a video signal to.

[0003] In this method, for example, file data T ₁ containing video data that the requester H ₁ is currently viewing.
Changed from when the requests viewing of another file data T _n, the video tape recorder R ₁ is at the feed side, the recorded video tape V ₁ of the file data T ₁
Needs to be replaced with the video tape V _n on which the file data T _n is recorded. Therefore, when viewed from the requestor H ₁ side, so that there arises a certain amount of wait time until the image or the like is received from the requesting.

If, for example, the requests of the requester H ₂ and the requester H _n are concentrated on the same file, for example, the file data T ₂ , the video tape V _{2 on} which the file data T ₂ is copied and recorded is supplied by the supplier. It is necessary to prepare more than one.

[0005] Therefore, instead of preparing a video tape recorder corresponding to each requester, the video supplier prepares a disk-shaped recording medium 100 storing compressed images as shown in FIG. Systems that respond to video signal playback requests have been considered. Disc-shaped recording medium 100
Stores compressed video data. Reading of the compressed video data from the disk-shaped recording medium 100 is performed by time division multiplexing. When compressed video data read out by division multiplexing is decompressed in a time axis extension unit 101, the requestor H _1, H ₂ ··· H _n decompression section provided on the side 102 _1,
102 ₂ ... 102 _n . This extension 102
_1, 102 ₂ ... decompression video information 102 _n is sent to the monitor device M _1, M _2, ... M _n.

The reading of compressed video data from the disk-shaped recording medium 100 is performed by time division multiplexing.
Video data compressed on a time axis per unit time is transmitted to a plurality of requesters. Here, the disc-shaped recording medium 100 can read out video information of a plurality of files at random in a unit time.

For example, this disk-shaped recording medium 100
Can be read out while randomly accessing video data for a time corresponding to nt, where n is the number of requesters who should reproduce and transmit the video every t seconds.

For this reason, in the reproducing system using the disk-shaped recording medium, the problems of the system using the video tape recorder described above can be solved to some extent.

For example, it is possible to eliminate the trouble of replacing video tapes when a file change request is made. Also,
This eliminates the need for duplicating video tapes of the same file in case requests are concentrated on the same file.

[0010]

By the way, even in the system using the above-mentioned disk-shaped recording medium, it is sometimes difficult to immediately start reproduction in response to a reproduction request from a requester. To read information data from a disk-shaped recording medium, an access time is required, which is the sum of the seek time, which is the time required for the read head to move to the information data storage position, and the waiting time until the disk-shaped recording medium rotates. It is said. This access time makes instant playback difficult.

Further, in a system capable of outputting a plurality of channels, when a plurality of requests are concentrated on the same file, instantaneous reproduction becomes more difficult. This is because, in order to reduce the influence of the access time loss of the disk-shaped recording medium, reading the video of each requested video file in large blocks increases the waiting time of the requester's turn. is there.

When the access time is fixed and the size of the data read block is changed, the data read efficiency changes as shown in FIG. The data readout efficiency is the efficiency with respect to the ability to originally transfer data in one second. In FIG. 17, the access time is 0.045 seconds, and the maximum read speed is 30 Mbps.
And The horizontal axis of FIG. 17 shows the size of the read block in units of time. For example, a read block having a size of 0.5 seconds refers to a case where data is continuously read for 0.5 seconds.

In FIG. 17, for example, when the size of the read block is 0.5 second, the transfer efficiency on the vertical axis is 0.917 (91.7%). Originally, 30
This is because the number of accesses must be increased because the size of the read block is only 0.5 seconds while having the transfer capability of Mbps. Further, assuming that the read block is 0.1 second, the transfer efficiency is 0.690 (6
9%).

Assuming that the maximum read speed shown in FIG. 17 is R, the size of the read block is B, and the access time is Ta, the read transfer efficiency RA can be expressed as RA = R × (B / (B + Ta)). Therefore, in order to increase the transfer efficiency, the size of the read block must be increased.

However, if the read block is enlarged in order to increase the transfer efficiency as described above, when the requester newly requests the reproduction of the file, the waiting time in the turn becomes longer. Will take a long time to arrive. Therefore,
The requester cannot instantly view the video.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides a data recording / reproducing apparatus capable of instantaneously reproducing a video without an influence of an access time loss in response to a video reproduction request of a requester. The purpose is to provide a data recording / reproducing method.

[0017]

According to the present invention, there is provided a data recording / reproducing apparatus for recording and reproducing file data including at least video data on a recording medium in a time-division manner and reproducing the same. At least one output unit to which the data reproduced from the recording / reproducing unit is input and output to the outside, and a cueing unit for temporarily storing a head portion of the video data among the data recorded on the recording medium When there is a request to instruct reading of the data, the data indicating the head of the video data stored in the cue storage is read and output, and the data following the head is output. Output from the recording / reproducing means, input to the output means, and output from the output means. Means, and characterized in that it comprises a control means for controlling the cueing storage means.

That is, according to the present invention, of the file data including the video data recorded in the data recording / reproducing apparatus in a time-division manner, the head of the video data is stored in the cue storage means. When there is a read request, the control means first reads the head of the video data of the file data from the cueing storage means, and then reads the file data following the head of the video data from the output means.

In order to solve the above-mentioned problems, a data recording / reproducing method according to the present invention is a first method for recording and reproducing file data including video data on a recording medium in a time-division manner.
And a second step of storing the data indicating the head of the video data among the data recorded in the first step in a cue memory, and a request to instruct reading of the data. When the data indicating the head portion stored in the second step is read out from the cueing memory and output, the data subsequent to the head portion is read out in the first step. And a third step of outputting from at least one output means.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a data recording / reproducing apparatus and a data recording / reproducing method according to the present invention will be described with reference to the drawings.

This embodiment is a video data recording / reproducing apparatus which records and reproduces a video data file on a recording medium in a time-division manner and reproduces video data from the recording medium in response to a video reproduction request from a requester. is there. As shown in FIG. 1, the video data recording / reproducing apparatus includes a recording / reproducing unit 1 for recording and reproducing file data of a video material on a recording medium in a time-division manner, and each file read from the recording / reproducing unit 1. A device interface 2 for performing format conversion and timing adjustment on data; an output unit 3 to which the file data reproduced from the recording / reproducing unit 1 is input via the device interface 2 and output to the outside; A cueing memory unit 4 for temporarily storing a head portion (hereinafter, file head portion information data) of the file data recorded on the first recording medium;
There is a selection unit 7 for selectively switching between each file data output from the output unit 3 and file head partial information data output from the cueing memory unit 4 and supplying it to the requester, and a request for reading the file data. Then, the file head portion information data stored in the cueing memory unit 4 is read and output, and the file data following the head portion is reproduced from the recording / reproducing unit 1 and input to the output unit 3. Control unit 50 for outputting from output unit 3
And The control unit 50 includes a memory control unit 5 that directly controls the recording / reproducing unit 1, the output unit 3, and the cueing memory unit 4, and a device control unit 6 that receives a file data read request from a requester.

As shown in FIG. 2, the recording / reproducing unit 1 includes eight disk devices D _{1 to} D ₈ and eight disk devices D ₁₁ to D ₁₁ .
A disk array unit 8 constituted by parallel arranged and D ₁₈ in two stages, consisting of disk array controller 9 for controlling the disk array unit 8. The disk array unit 8 records the distributed, interleaved and input file data under the control of the disk array control unit 9. Since the disk array unit 8 uses a large number of disk devices in parallel, it is possible to improve the recording capacity and the transfer speed, and to obtain higher reliability than a single disk device. In particular, in the recording / reproducing apparatus 1, the disk array control section 9 distributes file data in response to a command from the memory control section 5 and records the file data in the disk array section 8 in a time-division manner. By reading the file data distributed to the server, each file data is reproduced and transmitted to the requester.

The distributed file data of the video material file recorded in the disk array section 8 is generally compressed video data in which the information amount is compressed. The compression method includes a method of performing the compression on a frame basis and a method of performing the compression on a plurality of frames basis. In the method performed on a frame basis, a logical block serving as a unit for compression is an integral multiple of a frame. In the method performed in units of multiple frames, the logical block is
Basic unit for performing compression processing (for example, GOP: Group of PIC
TURES).

The output unit 3 adjusts the input / output transfer speed to supply the file data supplied from the recording / reproducing unit 1 via the device interface 2 to the requester as described above. The file data supplied from the disk array unit 8 of the recording / reproducing unit 1 to the output unit 3 via the device interface 2 is obtained by accessing a plurality of distributed data per unit time and has a high transfer rate. have. On the other hand, since the transfer speed of the file data output to the requester is low, the output unit 3 is required as an input / output means to adjust the transfer speed.

The output unit 3 has a plurality of user memories 3 ₁ , 3 ₂ ... 3 _n corresponding to the number of requesters.
Further, as described later, only one user memory may be provided so as to correspond to only one requester. Of the plurality of user memories 3 ₁ , 3 ₂ ... 3 _n , for example,
One user memory 3 ₁ is configured as shown in FIG. That is, the user memory 3 ₁ includes a memory 10 and the memory 11 and the other is a double buffer configuration can output data while the one in the data has been written,
The switching between the memories 10 and 11 is controlled by an instruction from the memory control unit 5 and a user memory address control unit 12 generates write and read addresses. The file data supplied from the recording / reproducing unit 1 via the device interface 2 is transferred to the memory 10 or the memory 11 so that the user memory address control unit 12 according to the instruction of the memory control unit 5 adjusts the transfer speed. Input and output. Memory 10
Alternatively, the file data output from the memory 11 is supplied to the selection unit 7.

The selection unit 7 determines whether the requesters H ₁ , H _2.
selector 7 in accordance with the number of _{n 1,} 7 has a ₂ · · · 7 _n,
Requesters H ₁ , H ₂ ... H _n according to the control of the memory control unit 5
And outputs each file data from the output unit 3 or each file head partial information signal from the cueing memory unit 4. Of course, the file head information signal is output for a predetermined time, for example, several tens of seconds, and then the file data following the file head information signal is output from the user memory unit 3.

The cueing memory section 4 stores the file head information signal which is the head of the file data via the device interface 2 as described above.
FIG. 4 shows the configuration of the cueing memory unit 4. That is,
The cueing memory unit 4 includes a cueing memory 14 into which a file head information signal via the device interface 2 is written and read out, and a cueing memory 14
And a cueing memory address control unit 13 for controlling writing / reading of a file head information signal to / from the memory.

The cueing memory address control section 13 is an n-times sampling section for sampling the video data read address supplied from the output section 3 using a clock n times the timing signal T _M supplied from the memory control section 5. 15, a write address generator 16 for generating a write address AD _W of the file head information signal at an instruction timing from the memory controller 5, and a read address AD of the file head information signal supplied from the n-times sampling unit 15. either one of the write address AD _W supplied from the _R and the write address generation unit 16 selects, based on an instruction from the memory control unit 5 consists of supplying the address selector 17. the cue memory 14.

The n-times sampling process performed by the n-times sampling unit 15 will be described with reference to FIGS.

The read address of the file data supplied from the user memory 3 ₁ of the output unit 3, a value address arithmetic unit 21 ₁ minus one file beginning address AD _H supplied from the memory controller 5, It is added by the adder 22 _1. The output signal of the adder 22 ₁ is supplied to the address data sequentially reading unit 23, sequentially read as sampled at n times the clock of the timing signal T _M supplied from the memory controller 5, the address selector 17 is supplied as a read address AD _R of the file head portion information signal. Read address is also the address of the video data supplied from the user memory 3 ₂ calculator 21
₂ is added to the signal (AD _H -1) supplied from the adder 22 ₂ , supplied to the address data sequential reading section 23, and the timing signal T _M supplied from the memory control section 5.
Read sequentially as sampled at n times the clock supplied to the address selector 17 as a read address AD _R of the file head portion information signal. The read address of the video data supplied from the user memory 3 _n is processed in the same manner.

[0031] Thus, in the case where transmission of the file head portion information signals from the cue memory 14 there are requester required, the read address from the user memory 3 ₁ (shown in (A) of FIG. 6), user a read address from the memory 3 ₂ (shown in (B) of FIG. 6), (shown in FIG. 6 (C)) read address from the user memory 3n is supplied to the cue memory address controller 13, n A value obtained by subtracting 1 from the address of the memory in which the file is stored is added inside the double sampling unit 15 and further sampled n times by n times clock to read out a file head partial information signal as shown in FIG. address AD _R is generated. Read address of the file head portion information signal AD _R is cue memory 14 through the address selector 17
Supplied to

The cueing memory address control unit 13 samples the read address from each of the user memories 3 ₁ , 3 _2, ... 3 _n by n times with the n times sampling unit 15. An address from the user memory which is not requested in the above is regarded as an invalid address.

The cueing memory address controller 1
Third address selector 17, under the control of the memory control unit 5 is supplied to the cue memory 14 by selecting a write address AD _W from the write address generator 16,
The file head information signal from the device interface 2, that is, the head of the file data is written.

The device control unit 6 accepts the request from each requester as described above, and instructs the memory control unit 5 to create and update an input / output schedule table as shown in Table 1.

[0035]

[Table 1]

The memory control unit 5 controls the data input / output of the recording / reproducing unit 1, the device interface 2, the output unit 3, and the cueing memory unit 4 based on the input / output schedule table created and updated by itself, and selects The data selection of the unit 7 is controlled.

A control unit 50 comprising a memory control unit 5 and a device control unit 6 controls each of the above units according to the data recording / reproducing method of the present invention. This data recording / reproducing method is roughly divided into a first step to a third step, and the memory control unit 5 executes each step as follows. That is, in the first step, the data file is recorded and reproduced in the recording / reproducing unit 1 in a time-division manner. In the second step, a file head information signal indicating the head of the data file among the data files recorded in the first step is stored in the cue memory unit 4. In the third step, when there is a request to instruct the reading of the file data, the file head partial information signal stored in the second step is read from the cueing memory unit 4 and output, An output unit 3 to which the data read out in the first step from the file data following the head portion is output, respectively
Output from

Next, a series of operations of the video data recording / reproducing apparatus of the present embodiment, that is, control from reproduction request of the requester to reproduction and transmission of video and flow of file data will be described with reference to FIGS. It will be described with reference to FIG. Figure 7 is a diagram for explaining the reproducing operation when the video data recording and reproducing apparatus of the present embodiment meet the new video playback request from requester H _8. FIG. 8 is a flowchart showing the control operation of the device control unit 6, and FIGS. 9 and 10 are flowcharts showing the operation of the memory control unit 5.

For example, when the requester H ₈ newly requests the reproduction of the file data T _A at the timing of t 1 in FIG.
Conventionally, the file data T requested by the requester H _8
A is delivered at t3 timing write block "8" has been completed, which is located after the write block requester H ₇ in one cycle "7".

[0040] In contrast, the present embodiment may store the file head portion information signal cueing memory section 4 is preliminarily file data T _A, new file data T _A is required at the timing of t ₁ also, it is possible to write the block "1" requester H ₁ at timing t ₂ ended, to play the file head portion information signals from the cue memory 4. Therefore, the requester H ₈ can provide file data requested immediately.

In order to execute the reproduction operation in response to the new video reproduction request, the processing shown in FIGS. 8 to 10 is executed. First, the device control unit 6 reads out a request list in which a requester and the requested file data are described (step S1 in FIG. 8). Then, in step S2, the device control section 6 starts communication relating to the new request read in step S1. Thereafter, the device control unit 6 determines whether or not the reception preparation of the memory control unit 5 is completed in step S3, and if the reception preparation of the memory control unit 5 is completed, the process proceeds to step S4. If it is determined that the preparation is not completed, the determination in step S3 is repeated until it is determined that the reception preparation is completed.

Next, in step S4, the device control section 6 determines whether or not there is a new request, that is, a change request in the request list read in step S1. Here, if it is determined that there is a new request, the device control unit 6 proceeds to step S5, and if it determines that there is no new request, the process proceeds to step S5.
Go to 10.

Next, the device control section 6 receives the judgment at step S4, and next judges at step S5 whether the change request is a new request or a stop request. Here, if it is determined that the request is a new request, the device control unit 6 proceeds to step S
Then, if it is determined that the request is a stop request, the process proceeds to step S7.

Next, the apparatus controller 6 which has proceeded to step S6
Informs the memory controller 5 of the contents of the new request, that is, the requester and the requested file data. On the other hand, the device controller 6 that has proceeded to step S7 notifies the memory controller 5 of the content of the stop request, that is, the deletion of the requester.

Next, in steps S8 and S9, the device control section 6 determines whether or not there is another request.
That is, the device control unit 6 determines whether the number n obtained by subtracting 1 from the number N of the request list read in step S1 is greater than 0, and determines whether there is another request. are doing. Here, if it is determined that n is greater than 0, there is another request, and the processing from step S5 is repeated. On the other hand, if it is determined that n is not larger than 0, there is no other request, and step S10
Proceed to.

Next, at step S10, the device control unit 6
Receives the determination result of the above step S4 or S9,
Inform the memory controller 5 of the end of the change processing, and
At 11, it is determined whether or not completion has been confirmed by the memory control unit 5. Here, if there is a confirmation of completion from the memory control unit 5, the processing from step S1 is newly repeated. The determination of completion in step S11 is repeated until completion confirmation is obtained, and the processing from step S1 is stopped during this period.

For example, a new request notified to the memory control unit 5 by the processing described above from the device control unit 6 is:
If it is new reproduction request information relating to the file data T _A from the requester H ₈ , the memory control unit 5 enters this new reproduction request information in the following processing shown in FIGS. 9 and 10 as shown in Table 1 above. In addition to the output schedule table, in response to a video playback request for the file data T _A from the requester H ₈ , the playback and transmission of the file data T _A are performed at the timing shown in FIG.

First, the memory control unit 5 waits for communication from the device control unit 6 in step S21 in FIG. This is Figure 8
This is processing corresponding to step S2 of FIG. Next, the memory control unit 5 notifies the device control unit 6 of the completion of the preparation for accepting the change in step S22. This corresponds to step S3 in FIG. Then, the memory control unit 6 returns the user pointer of the input / output schedule table shown in Table 1 to the top in step S23.

Next, the memory control unit 5 determines whether or not there is a change request from the device control unit 6 in step S24. Here, when determining that there is a change request, the memory control unit 5 proceeds to step S25, and when determining that there is no change request, proceeds to step S28.

Next, in step S25, the memory control unit 5
Determines whether the change request is a new request or a deletion request. Here, if it is determined to be a new request, the last part of the memory controller 5, the new requests, output schedule table example a new request for file data T _A requester H ₈ as shown in Table 1 Add to On the other hand, if it is determined that the request is a cancellation request, that is, a deletion request, the memory control unit 5 deletes the request corresponding to the deletion request from the input / output schedule table of Table 1.

Step S26 or Step S2
When the process of step 7 is completed, the memory control unit 5 notifies the device control unit 6 of the completion of the table creation. If there is no requester in the table created here, the memory control unit 5 repeats the processing from step S21 (step S29).

Next, the memory control unit 5 determines in step S30
Instructs the recording / reproducing unit 1 to output a block of the requested file data based on the input / output schedule table shown in Table 1 created by the processing up to step S29,
The output unit 3 is instructed to take in blocks output from the recording / reproducing unit 1 via the device interface 2.

Then, the user memory address control unit 12 shown in FIG. 3 writes the block following the file head information signal into the memory 10. When the memory 10 becomes full, the writing to the memory 11 is switched. in this way,
The user memory address control unit 12 switches the writing between the memory 10 and the memory 11 according to an instruction from the memory control unit 5. Then, the writing is switched alternately until all the remaining blocks of the file data are exhausted.

Here, when the writing to the memory 10 is completed and the writing to the memory 11 is switched,
Starts reading from.

The write and read operations of the block following the file head partial information signal by the user memory address control unit 12 will be described with reference to FIG. When writing the block i to the write addresses 1 to m of the memory 10 by the user memory address control unit 12,
From the read addresses 1 to m of the memory 11, the block i
-1 has been read (FIG. 12A). Memory 1
When the writing to 0 is completed, the block i is read from the read addresses 1 to m of the memory 10 and the block i + 1 is written to the write addresses 1 to m of the memory 11, as shown in FIG. . When the writing to the memory 11 is completed, as shown in FIG. 12C, the block i + 1 is read from the read addresses 1 to m of the memory 11 and the block i + 2 is written to the write addresses 1 to m of the memory 10. It is.

Writing is completed for all requesters in the cycle time shown in FIG. In the write block shown in FIG. 7, the file data of the cycle time portion of one requester is written. On the other hand, reading is performed by the requester 1
The block takes one cycle time.

Conventionally, block writing is performed for each requester. In addition, they are performed in the order requested. In Figure 7, the order of the requester _{H 1, H 2, H 5} , H 4, H 3, H 9, H 7, H 8. s1, s2 and s3 are empty blocks. Since the writing of the block relating to the file data T _A requested by the new requester H ₈ is performed last, conventionally, as described above, the waiting time takes only the period indicated by WT from t1 to t3.

Therefore, in this embodiment, the waiting time WT
In order to shorten the length of the file, the cueing memory unit 4 sends out a file head partial information signal until a video is sent from the recording / reproducing unit 1. In FIG. 7, the transmission of the file head partial information signal from the cueing memory unit 4 starts from the position of the first write block "2" after the request made at t1, is performed for seven blocks, and is performed in "8" blocks. Is switched to the video data written in the memory 10 of the user memory unit 3. Therefore, the first block from the recording / reproducing unit 1 is exactly the next block in consideration of the waiting time WT, and is not the head of the file data. Note that the sub-block obtained by dividing the read block of each requester by the allowable maximum number of requesters (10 in the example shown in FIG. 7) needs to be an integral multiple of a frame or an integral multiple of a GOP.

As described above, the memory controller 5 of the controller 50
Instructs the cueing memory unit 4 to transmit a file head part information signal of the requested file data when a new request is received, and, simultaneously, instructs the selection unit 7 to select the file heading information on the cueing memory unit 4 side. Instructs to select a partial information signal. The writing of all the file head information signal blocks of each file data into the cueing memory unit 4 has been performed in advance. Recording / reproducing unit 1 in memory 10
When the first writing from is completed and the reading is started, the memory control unit 5 makes the selection unit 7 select the output unit 3 side.

This operation can be realized by adding the processing shown in FIG. 10 after the processing of the memory control unit 5 shown in step S30 in FIG. That is, the memory control unit 5
Means that the instruction issued in step S30 is, for example, the requester H ₈
Of whether a new request is determined in step S31 regarding the file data T _A, when was a novel request, file data T of the new file data e.g. requester H8 to cue memory unit 4 proceeds to step S32 Tell _A. Then, the memory control unit 5 switches the requester H ₈ minutes of the selector 7 ₈ in the selector 7 to the cue memory unit 4 side.

Next, in step S33, the memory control section 5 increases the read address of the block of the recording / reproducing section 1 by the number of blocks. Then, after the processing for the requester H for ₈ minutes, in step S34, the presence or absence of a block remaining is checked. If there is a block remaining, the process proceeds to step S35 to increase the user pointer by one. On the other hand, if there is no remaining block, the flow advances to step S36 to delete the change request from the table. Upon completion of the process in the step S35 or the step S36, the process returns to the step S24 in FIG.

Here, a specific example of the operation will be described in detail with reference to FIG. As the recording / reproducing unit 1, a disk array in which eight disk units each having a maximum transfer speed of 30 Mbps and an access time of 0.045 seconds are connected in two stages in parallel is used, and the transfer speed to the requester is 4 Mbps. And In addition, the block length per requester is set to the efficiency of 0.917 in FIG.
Assuming that 0.5 seconds at the time of (reading speed 27.5 Mbps), in the present embodiment, 27.5 Mbps × 8 units / 4 Mbps (= 55) can simultaneously support up to 55 requesters. Conventionally, the waiting time when there are a maximum of 55 requesters is 27.5 seconds (= 0.5 seconds ×
55), and a waiting time of 27.5 seconds at the worst occurs before the new requestor views the video. However, in this embodiment, the time is 0.5 second or less.

If the block length per requester is 0.1
In seconds, the efficiency is 0.690, and the maximum number of requesters that can be supported is 41. In this case, conventionally,
The waiting time is 4.1 seconds, but in this embodiment, it is 0.1 seconds or less.

In the video signal transmitting apparatus according to the present embodiment, the output section may be configured as shown in FIG. That is,
The output unit 30 includes a user memory address control unit 31 and a memory 32. As shown in detail in FIG. 13, the memory 32 has a writing area 32a indicated by hatching.
.Alpha. Area for preventing the data written in the read area before reading from being lost. This α area is approximately the writing area 32a / the maximum number of requesters.

First, the write address 1 of the write area 32a is controlled by the user memory address control unit 31.
When the block i is written into the blocks i to m, the block i-1 is read from the read addresses m + 1 to m + n ((A) in FIG. 13). Next, when writing the block i + 1 to the write addresses m + 1 to mn of the write area 32a under the control of the user memory address control unit 31, the block i is read from the read addresses mn + 1 to m ((B in FIG. 13). )). And block i
When +2 is written to the write addresses mn + 1 to m-2n, the block i + 1 is read address m-2n +
1 to mn ((C) in FIG. 13).

The video data recording / reproducing apparatus may use the output unit 3 having only one user memory.
For example, as when using the output unit 3 having only user memory 3 ₁ shown in FIG. 14, and only supplying file data to the requester H _1, firstly the cue memory section 4 to the request It sends the file head information signal and sends with the selector 7 ₁ data file continued from the user memory 3 ₁ in the file head information signal subsequently. Therefore, it is possible to provide by reproducing the file data requested instantaneously simultaneously most requests and the requestor H _1.

In the above embodiment, a video data file is used as information data. However, file data including at least video data such as an audiovisual (AV) data file may be used. Also, file data that handles character information together with video data may be used.

[0068]

According to the present invention, it is possible to instantaneously reproduce and provide a video without an influence of access time loss in response to a video reproduction request of a requester.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a video data recording / reproducing apparatus which is a preferred embodiment of a data recording / reproducing apparatus of the present invention.

FIG. 2 is a diagram showing a specific example of a configuration of a recording / reproducing unit of the video data recording / reproducing device.

FIG. 3 is a block diagram showing a specific example of a configuration of an output unit of the video data recording / reproducing apparatus.

FIG. 4 is a block diagram showing a specific example of a configuration of a cueing memory unit of the video data recording / reproducing apparatus.

FIG. 5 is a block diagram showing a specific example of a configuration of the n-times sampling unit shown in FIG. 4;

FIG. 6 is a timing chart for explaining an operation of a specific example of the cueing memory unit shown in FIG. 4;

FIG. 7 is a diagram for explaining the operation of the video data recording / reproducing device.

FIG. 8 is a flowchart showing a process of a device control unit of the video data recording / reproducing device.

FIG. 9 is a flowchart showing processing of a memory control unit of the video data recording / reproducing apparatus.

FIG. 10 is a flowchart showing processing of a memory control unit of the video data recording / reproducing apparatus.

FIG. 11 is a block diagram showing another specific example of the output unit of the video data recording / reproducing apparatus.

FIG. 12 is a diagram for explaining the operation of the output unit shown in FIG. 3;

FIG. 13 is a diagram for explaining the operation of another specific example of the output unit shown in FIG. 11;

FIG. 14 is a block diagram showing a video data recording / reproducing apparatus using an output unit having only one user memory.

FIG. 15 is a diagram for explaining a method of transmitting a video signal using a video tape recorder, which has been conventionally performed.

FIG. 16 is a diagram for explaining a method of transmitting a video signal using a disk, which has been conventionally performed.

FIG. 17 is a characteristic diagram showing a change in data read efficiency with respect to the size of a read block.

[Explanation of symbols]

1 recording / playback unit, 2 device interface, 3
Output unit, 4 cue memory, 5 memory control unit, 6 device control unit, 7 selection unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-222022 (JP, A) JP-A-55-105874 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 3/06 540

Claims (4)

(57) [Claims] 1. A recording / reproducing means for recording and reproducing file data including at least video data in a time-division manner on a recording medium, and at least one of said data reproduced from said recording / reproducing means being inputted and outputted to the outside. Output means, cueing storage means for temporarily storing the head of the video data of the data recorded on the recording medium, and cueing storage means when there is a request to read out the data. While reading and outputting the data indicating the head of the video data stored in
Control means for controlling the recording / reproducing means, the output means, and the cueing storage means to output the data following the head portion from the recording / reproducing means, input the data to the output means, and output the data from the output means. A data recording / reproducing device comprising: 2. The data recording / reproducing apparatus according to claim 1, wherein said recording / reproducing means records and reproduces file data including at least video data in a time-division manner on a randomly accessible disk-shaped recording medium. . 3. The data recording / reproducing apparatus according to claim 2, wherein said disk-shaped recording medium comprises a disk array unit for recording / reproducing on / from a plurality of disk devices in parallel. . 4. A first step of recording and reproducing file data including video data in a time-division manner on a recording medium, and wherein the data recorded in the first step indicates a head portion of the video data. A second step of storing the data in the cueing memory; and when receiving a request to read the data, read and output the data indicating the head portion stored in the second step from the cueing memory. And outputting the data following the head portion from at least one output unit to which the data read in the first step is output. Playback method.