JPH1169310A - Data reproduction control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the waste of time slot in a reverse reproduction mode by storing the video data blocks equivalent to every period of the time slot in a buffer memory and reading reversely the stored data equivalent to one period out of the final video data block to perform the reverse reproduction. SOLUTION: When the video data equivalent to one period are stored in a buffer memory 6041A, the storing buffer memory is switched to a buffer memory 6041B and the memory 6041A is used as a reproducing buffer memory. In other words, the buffers 6041A and 6041B are prepared to store the data equivalent to one period and the reproduction is started for the data stored in both buffers 6041A and 6041B after the data equivalent to one period are stored. Thereby, the data can be read out in the direction of a time slot of the normal reproduction even in the reverse reproduction mode. Thus, the time slot can be effectively used with no disturbance of control of the time slot.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data reproduction control method, and more particularly, to a data reproduction control method for reading out images stored in a storage medium such as a disk in reverse order.

[0002]

2. Description of the Related Art As an example of a conventional video-on-demand system, for example, Japanese Patent Application Laid-Open No. 8-88845 discloses a video-on-demand system capable of immediately responding to a request from a terminal device even when the number of storage media increases. A demand system has been proposed. FIG. 6 shows an example of the configuration of the video-on-demand system described in the above publication. Referring to FIG. 6, the video-on-demand system includes a storage device 6.
01, the data reading device 602, and the memory writing device 60
31-603n and buffer memories 6041A-604
nA, buffer memories 6041B to 604nB, memory reading devices 6051 to 605n, and a terminal device 6061.
To 606n and a control device 607. In addition, the storage device 601 includes a plurality of storage media 6011 to 6014 formed of, for example, magnetic disks.

[0003] The video data stored in the storage device 601 is read out through the data reading device 602, and is temporarily stored in each of the buffer memories 6041A to 604nA or 6041B to 604nB. The data stored in the buffer memories 604A to 604nA or the buffer memories 6041B to 604nB are read by the memory reading devices 6051 to 605n, sent to the terminal devices 6061 to 606n, expanded, and then reproduced and displayed.

[0004] The control device 607 comprises terminal devices 6061 to 6061.
By controlling the storage device 601 and the data reading device 602 based on the distribution request signal input from the storage device 606n, the video data stored in the storage device 601 can be transferred via the data reading device 602 to 6041A to 604nA or the buffer memory 6041B. ６０604 nB. The reason why two buffer memories are provided is to prevent data being reproduced from being overwritten. If the buffer memory 6041A is used as a buffer memory for reproduction, the buffer memory 6041B is used as a buffer memory for storage, and the roles of the two buffers are switched at regular time intervals.

In this conventional video-on-demand system, video data is divided into predetermined lengths and stored in a storage device 601 cyclically.

FIG. 7 shows how video data is stored in a storage medium when the number of storage media 6011 to 601n constituting the storage device 601 is four (n = 4). Referring to FIG. 7, the video data VD is divided into video blocks VD-001, VD-002,..., VD-n, and stored in the storage media 6011 to 6014 in order. That is, video blocks VD-001 to VD-0
04 is stored in the storage media 1 to 4 in order, and the video block V
D-005 is stored in the storage medium 1 again, and subsequently, video blocks VD-006 to VD-008 are stored in the storage media 2 to 4 in order.

Referring again to FIG. 1, video data VD stored in storage medium 601 is read by data reading device 602 and finally terminal devices 6061 to 606.
It is reproduced and displayed by any one of n.

FIG. 8 is a diagram showing the relationship between the reading time from the storage device 601 and the reproduction display time on the terminal device 6061. Video data VD stored in storage medium 6011
−001 is read out during the video data read time DTread seconds and stored in the buffer memory 6041A. In the terminal device 6061, the video data reproduction time DTpl
Play over time.

Suppose now that the video data read time DTrea
Assuming that d is 1/4 of the video data playback time DTplay, four video blocks can be read from the storage medium 6011 within one block of video data playback time.

A case where the video data VD is reproduced by the terminal device 6061 will be described with reference to FIGS. The video data VD-001 stored in the storage medium 6011 is read through the data reading device 602 and is passed to the memory writing device 6031. Memory writing device 6031
Selects the buffer memory 6041A for storage,
Store the data. When the data is stored, the buffer memory 6041A is used for reproduction, and the data is read from the memory reading device 6051 and reproduced and displayed on the terminal device 6061. Before the reproduction and display is completed on the terminal device 6061, the data reading device 602 transmits the next video data VD-00.
2 is read from the storage medium 6012 and stored in the buffer memory 6041B through the memory writing device 6031. In this way, the terminal device 6061 reproduces and displays the video without interruption.

Here, the necessary next video data may be stored in the buffer memory before the reproduction and display of the previous video data is completed. Therefore, if the video data read time is shorter than the reproduction display time, the data read is performed. The device 602 can read other video data from the same storage medium.

FIG. 9 shows that during the reproduction display time DTplay,
FIG. 5 is an explanatory diagram showing an example of reading four pieces of video data.
There are four types of video data, VD1, VD2, VD3, and VD4, and the data reading device 602 includes a storage medium 6011
(Storage medium 1) to video data block VD-001,
VD2-001, VD3-001, and VD4-001 are sequentially read out, and the buffer memories 6041A to 6041A-6 are respectively read.
044A. Terminal devices 6061 to 6064
Then, when the video data blocks are received, they are expanded and reproduced and displayed.

Before the reproduction and display of each of the terminal devices 6061 to 6064 are completed, the video data block VD-00
2, VD2-002, VD3-002, VD4-002
Is read from the storage medium 6012 (storage medium 2), and the video is reproduced and displayed on the terminal device without interruption.

As described above, when four storage media capable of securing four time slots per frame are used, it is possible to provide different video images to 4 × 4 = 16 terminal devices as a whole.

[0015]

However, in the case of performing the reverse reproduction in the above-mentioned conventional video reproduction method,
The direction of the time slot for reverse reproduction is opposite to the direction in which the time slot for other forward reproduction advances.
FIG. 10 is a diagram for explaining a problem of the related art. Time slots TS-1 to TS-3 for forward reproduction
Is the storage medium 6011 (storage medium 1) → the storage medium 601
2 (storage medium 2) → storage medium 6013 (storage medium 3) →
Storage medium 6014 (storage medium 4) → storage medium 6011
It moves in the order of (storage medium 1).

However, the time slot TS-R for reverse reproduction is stored in the storage medium 6014 (storage medium 4).
→ Storage medium 6013 (Storage medium 3) → Storage medium 6012
Since it moves in the order of (storage medium 2) → storage medium 6011 (storage medium 1) → storage medium 6014 (storage medium 4), in order to schedule without collision, as shown in FIG. It is necessary to leave a time slot column for reproduction, and there is a problem that waste occurs (especially, when reverse reproduction is frequently used, time slot management efficiency is reduced).

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to avoid wasting time slots when performing reverse reproduction in a video reproduction system using time slots. It is an object of the present invention to provide a data reproduction control method as described above.

[0018]

According to a first aspect of the present invention, there is provided a data reproduction control system for reproducing data by time slot management.
The video data block for each one cycle of the time slot is read out in accordance with the movement of the time slot and stored in the buffer memory. After the data for one cycle is accumulated, the video data block is read out in the reverse direction from the last video data block. It is characterized by performing reverse reproduction.

The second invention of the present application (claim 2) is characterized in that a necessary capacity is allocated from the common memory area as needed as the buffer memory, and an unnecessary area is released to the common memory area as needed. And

In the third invention of the present application (claim 3), at the time of starting the backward reproduction, one time is utilized by utilizing the vacant time slot.
It is characterized in that a plurality of video data blocks of the video data for the cycle are read into the buffer memory as soon as possible.

[0021]

Embodiments of the present invention will be described. According to the data reproduction control method of the present invention, in a preferred embodiment, a video data block for one cycle of a time slot is read out in accordance with the movement of the time slot and stored in a buffer memory, and data for one cycle is stored. After the data is stored, the data is read in the backward direction from the last video data block to perform reverse playback.

That is, two buffers capable of storing data for one cycle are prepared, and after the data for one cycle is stored, reproduction of the data in the buffer is started. For this reason, even when performing reverse reproduction, data can be read out in the order of the time slot of normal reproduction, and the time slot can be effectively used without disturbing the control of the time slot.

In a preferred embodiment of the data reproduction control method of the present invention, a buffer memory is dynamically secured from a memory pool when it becomes necessary, and the buffer memory is released when it is no longer needed. With this configuration, the same effect can be achieved with a smaller memory amount than preparing two memories for one cycle.

Further, the data reproduction control method of the present invention
In the preferred embodiment, at the start of reverse playback,
A plurality of video data blocks of video data for one cycle are read into the buffer memory as soon as possible using the vacant time slots. For this reason, the reverse reproduction can be started in a shorter time after receiving the reverse reproduction start signal from the user.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; The data reproduction control method of the present invention can be implemented by using the conventional data reproduction device shown in FIG. Hereinafter, FIG. 6 will be referred to in the description of one embodiment of the present invention, but the description of the parts already described, such as the device configuration, will be appropriately omitted to avoid duplication.

FIG. 1 is an explanatory diagram for explaining an outline of the operation of the data reproduction control method according to one embodiment of the present invention. The buffer memories 6041A and 6041 shown in FIG.
41B is schematically shown. Buffer memory 6
041A and 6041B each have a capacity capable of storing video data blocks for the number of storage media, that is, video data for one cycle.

The data reading device 602 includes a storage device 601
, Video data for one cycle is sequentially read out and stored in the buffer memory 6041A. Buffer memory 60
When one cycle of data is stored in 41A, the memory reading device 6051 reads the video data from the last block in reverse order and sends it to the terminal device 6061. While the video data is being read from the buffer memory 6041A, the data reading device 602 stores the next one cycle in the storage device 601.
, And is read out in the same direction as the movement of the time slot of the forward reproduction, and written into the buffer memory 6041B.
Thus, the buffer memories 6041A and 6041
B transmits data to the terminal device 6061 while alternately repeating writing and reading, and the terminal device 6061 reproduces data in the opposite direction.

Next, the operation of this embodiment will be described more specifically with reference to the flowchart of FIG. 2 and the explanatory diagram of FIG.
As the video data, a case is considered in which blocks from VD-013 to VD-004 of the video data VD shown in FIG. 7 are reproduced in the reverse direction. In this example, one cycle of data is four blocks from VD-013 to VD-010.

First, when there is a request for reverse reproduction from the terminal, if there is a vacant time slot for the storage media 6011 to 6014, reading is started therefrom (step 201).

It is assumed that there is a free time slot for the storage medium 6013 (storage medium 3). Then, the video data block VD-011 in the first frame of FIG.
Is read and stored in the buffer memory 6041A (step 202). At this time, since data for one cycle has not been read out yet (No in the determination of step 203), the second frame also has the same direction as the time slot of the forward reproduction, that is, the storage medium 6014 (storage medium 3). , The video data block VD-012 is read out and stored in the buffer memory 6041A. Similarly, in the third frame, the video data block VD-013 from the storage medium 6011 (storage medium 1), and in the fourth frame, the video data block VD-01 from the storage medium 6012 (storage medium 2).
-010 is read and stored in the buffer memory 6041A.

The video data for one cycle is stored in the buffer memory 6.
041A (Yes branch of step 203), the storage buffer memory is buffer memory 6041
B, and the buffer memory 6041A is used as a reproduction buffer memory (see the reproduction buffer 6041A of FIG. 1) (step 204).

From the fifth frame, the memory reading device 60
51 is read from the buffer memory 6041A in reverse order from the last video data VD-13 and sent to the terminal device 6061. That is, in the fifth frame, the video data block VD-007 is read and stored in the buffer memory 6041B (step 205), and at the same time, the video data VD-11 is read from the buffer memory 6041A and reproduced ( Step 206).

Similarly, in the sixth frame, the video data block VD-008 is read and the buffer memory 60
41B and at the same time, buffer memory 6041A
The video data VD-10 is read and reproduced.

In this way, it is possible to perform reverse reproduction while reading from the storage device 601 in the same direction as the forward reproduction time slot.

FIG. 4 is an explanatory diagram schematically showing the operation of the buffer memory according to the second embodiment of the present invention. In the first embodiment of the present invention, the capacity of each of the buffer memories 6041A and 6041B is set to one cycle. However, in the second embodiment of the present invention, the buffer memory is secured from a common memory pool. I have. That is, when writing to the buffer memory becomes necessary, a buffer memory for one block is secured from the memory pool 401, and returned to the memory pool when the buffer memory for one block becomes unnecessary. The unit for securing and returning the memory does not have to be one block. For example, if the unit of reading from the storage device 601 is 1 block or less, a memory may be secured for each reading in accordance with the reading unit. Memory may be returned to the memory pool.

FIG. 5 is an explanatory diagram schematically showing the operation of a time slot in the third embodiment of the present invention. In the figure, hatched portions represent vacant time slots. At this time, when a reverse playback request is received from the terminal device 6061, data reading for one cycle is assigned to an empty time slot. For example, in FIG. 5, the data blocks VD-010 and VD
-011 and VD013 are read out and stored in the buffer memory 6
041A. In the subsequent second frame, the data block VD-011 that could not be read is read. Since one round of the video data has been read in the second frame, a time slot for reverse reproduction is allocated to a vacant time slot, and the video data is read and reproduced and displayed as in the first embodiment. .

[0037]

As described above, according to the present invention, the following effects can be obtained.

According to the first invention of the present application (claim 1), even in the case of the reverse reproduction, the disk can be accessed to the buffer for one time slot in the same order as the forward reproduction. Does not hinder the movement of the time slot. Therefore, it is not necessary to secure one row of time slots for reverse reproduction, and time slots can be used effectively.

According to the second invention of the present application (claim 2),
When necessary as buffer memory for temporarily storing data, it is secured from the common memory pool area, and when it is no longer needed, it is returned to the common memory pool, so the amount of memory used during reverse playback is reduced be able to.

Further, according to the third invention of the present application (claim 3), only at the start of the reverse reproduction, the video data of the first cycle is read at once by using the vacant time slot, so that the reverse reproduction is performed. , The waiting time from when the reverse reproduction is started until the instruction is issued can be shortened.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a storing operation to a buffer memory and a reading operation in a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the first exemplary embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an operation of a time slot in the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an operation of a buffer memory according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an operation of a time slot according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a conventional video-on-demand system.

FIG. 7 shows a conventional video on demand system.
FIG. 4 is an explanatory diagram illustrating a state where video data is distributed and stored in a plurality of storage media.

FIG. 8 is an explanatory diagram showing a timing relationship between a read time from a storage device and a reproduction display time on a terminal device in a conventional video-on-demand system.

FIG. 9 is an explanatory diagram schematically showing a method of reading four pieces of video data within a reproduction display time.

FIG. 10 is an explanatory diagram schematically showing a problem at the time of reverse reproduction in a conventional video-on-demand system.

[Explanation of symbols]

601 Storage device 6011 to 6014 Storage medium 602 Data reading device 6031 to 603n Memory writing device 6041A to 604nA, 6041B to 604nB Buffer memory 6051 to 605n Memory reading device 6061 to 606n Terminal device 607 Control device DTRead Data reading time DTPlay Reproduction display time

Claims (4)

[Claims] In a data reproduction control method for reproducing data by time slot management, a video data block for one time slot period is read out according to the movement of the time slot and stored in a buffer memory. A data reproduction control method comprising: reading out data from the last video data block in the reverse direction after the data is accumulated, and performing reverse reproduction. 2. A data reproducing apparatus according to claim 1, wherein a necessary capacity is allocated from a common memory area as needed as said buffer memory, and an unnecessary area is released to said common memory area as needed. control method. 3. The method according to claim 1, wherein a plurality of video data blocks of one cycle of video data are read into said buffer memory as soon as possible using a vacant time slot at the start of reverse reproduction. Data reproduction control method described. 4. A first and a second buffer memory having a capacity corresponding to one cycle of a time slot are prepared, and the time slot is first moved to the first buffer memory by one cycle at the end of data to be reproduced in the reverse direction. Data is read out from the first buffer memory in the reverse reproduction order and reproduced at the same time, and data for one cycle following the second buffer memory is moved in the direction in which the time slot moves. When data for one cycle is read to one buffer memory and data is reproduced from the other buffer memory, the roles of both buffer memories are exchanged and continued until the reverse reproduction is completed. A data reproduction control method wherein reverse reproduction is enabled while reading data in the order of slot movement.