JP3705107B2 - Stream data reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for reading stream data.
[0002]
[Prior art]
Conventionally, when reading stream data, data is acquired from the stream every time a read request is made, so that time (overhead) spent on access processing to the stream occurs each time. For this reason, when the number of accesses is large, the processing time increases, which increases the processing load of the stream data reading unit.
[0003]
One prior art is disclosed in JP-A-8-147234. The present invention relates to a stream processing apparatus that stores moving image or audio stream data in a storage device such as a magnetic disk unit and supplies the stream data in response to an external request. In particular, this is a technique for efficiently processing stream input / output requests with different speeds by managing schedules of external input / output devices, storage devices, and buffer memories by the MPU. Regarding the reading of stream data in this technique, stream data is acquired from an external source every time there is a request.
[0004]
Another prior art is disclosed in Japanese Patent Laid-Open No. 10-031559. In the case of transferring stream data from a video camera or the like to another device, a high-speed read / write speed storage unit that temporarily stores the stream data, and the read / write speed of data that is the transfer partner The present invention relates to the transfer of stream data to / from a slow external storage device. Specifically, a storage unit for temporarily used stream data is inserted before and after the storage unit to support transfer processing. This is a technique for reducing the free capacity required for the storage unit and reducing the overall processing time. In this technique, the acquisition of stream data when reading the stream data is performed from a device such as a video camera or an external storage device every time there is a request.
[0005]
As described above, in any of the conventional techniques, it is necessary to access an external device, a storage device, or the like every time stream data is requested, regardless of the number of requested data. In particular, when a small amount of stream data is read continuously, the overhead increases due to an increase in the number of accesses, and a stream data read processing time is required.
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an apparatus that reduces the time (overhead) spent for processing for accessing stream data and improves processing efficiency.
[0007]
Another object of the present invention is to provide a reading apparatus that shortens the time required for reading stream data when reading stream data.
[0008]
Still another object of the present invention is to provide an apparatus for reducing the overhead and improving the processing efficiency, particularly when a request for reading a small amount of stream data is continuously generated.
[0009]
Still another object of the present invention is to provide a reading device that shortens the time required to read stream data, particularly when a small amount of stream data read requests are continuously generated.
[0010]
[Means for Solving the Problems]
The figure numbers and symbols in the means for solving the problems are described in order to show the correspondence between the claims and the embodiments of the invention, and are used for the interpretation of the claims. Must not.
[0011]
In order to solve the above problems, the stream data reading device (FIGS. 1 and 7) of the present invention includes a return buffer (FIGS. 1 and 1) as a designated location, a prefetch buffer (FIGS. 1 and 3), a stream, In response to the data read request, the requested stream data is read from the stream data (FIGS. 1 and 4), the read stream data is stored in the prefetch buffer (FIGS. 1 and 3), and the requested data is stored. Stream reading unit (FIGS. 1 and 2) provided with means for transferring the requested stream data stored in the prefetch buffer (FIGS. 1 and 3) to the return buffer (FIGS. 1 and 1) It is characterized by comprising.
[0012]
Further, in response to the prefetch buffer (FIGS. 1 and 3) and the stream data read request, the requested stream data is read from the stream data (FIGS. 1 and 4) and read to the prefetch buffer (FIGS. 1 and 3). A stream comprising means for storing the requested stream data and transferring the requested stream data or the requested stream data stored in the prefetch buffer (FIGS. 1 and 3) to a specified location. And a reading unit (FIGS. 1 and 2).
[0013]
Further, when the stream data is insufficient with only the stream data transferred to the designated location, the stream reading unit (FIGS. 1 and 2) again determines the size of the prefetch buffer (FIGS. 1 and 3). The requested stream data is read out from the stream data (FIGS. 1 and 4), the read stream data is stored in the prefetch buffer (FIGS. 1 and 3), and the prefetch buffer (FIGS. 1 and 3). The deficient stream data is transferred to the designated location from the requested stream data stored in (1).
[0014]
Further, when the stream data is insufficient only with the stream data transferred to the designated location, the stream reading unit (FIGS. 1 and 2) again converts the insufficient stream data to the stream data (FIGS. 1 and 4). ), And the read insufficient stream data is transferred to the designated location.
[0015]
Further, the prefetch buffer (FIGS. 4 and 13) is included in a stream read unit (FIGS. 4 and 12).
[0016]
Furthermore, the stream reading unit (FIGS. 1 and 2) includes a buffer memory (FIGS. 1 and 5) for transferring the requested stream data that has been read, and the return buffer (FIGS. 1 and 1) includes stream data It is a memory area secured in the buffer memory (FIGS. 1 and 5) when a read request is made.
[0017]
Furthermore, a prefetch buffer (FIGS. 1 and 3) different from the prefetch buffer can be set inside the buffer memory (FIGS. 1 and 5).
[0018]
Further, the size of the prefetch buffer (FIGS. 1 and 3) is variable.
[0019]
Furthermore, it is included in devices used for PDC, PHS, and other mobile communications, and receives stream data wirelessly.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a stream data reading apparatus according to the present invention will be described with reference to the accompanying drawings, taking a mobile phone as an example. In this example, stream data is obtained from an access point (not shown).
[0021]
(Example 1)
FIG. 1 is a block diagram showing an embodiment (Embodiment 1) of the present invention, which comprises a return buffer 1, a stream reading unit 2, a prefetch buffer 3, a buffer memory 5, and a control unit 6. The stream data reading device 7 of the present invention in this embodiment is present inside a mobile phone.
[0022]
The stream data 4 indicates sequential information transmitted from a network destination or various devices including information related to a communication protocol.
[0023]
The control unit 6 controls the function of the mobile phone. A stream data read request to the stream data read device 7 according to the present invention is also issued from here. In addition to the control unit for the entire mobile phone, a control unit 6 dedicated to the stream data reading device 7 can be provided.
[0024]
The return buffer 1 is an internal area of the buffer memory 5 (described later) that is given to the stream reading unit 2 (described later) when the stream data reading request is sent from the control unit 6 to the stream data reading device 7. The return buffer 1 is used as a transfer destination of the requested stream data read by the stream reading unit 2.
[0025]
The stream read unit 2 has a function of reading the requested stream data from the stream data 4 in response to the stream data read request from the control unit 6. The read stream data is written in a prefetch buffer 3 (described later), and the written requested stream data is read from the prefetch buffer 3 (described later). In addition, a function of transferring the requested stream data read from the stream data 4 and the requested stream data written in the prefetch buffer 3 (described later) after reading from the stream data to the return buffer 1. have.
[0026]
The prefetch buffer 3 is connected to the stream reading unit 2 and stores the requested stream data read from the stream data by the stream reading unit 2.
[0027]
In response to the stream data read request from the control unit 6, the buffer memory 5 temporarily stores data when the stream read unit 2 outputs the requested stream data read from the stream data. It is. The return buffer 1 is secured when the stream data is read. The requested stream data transferred to the return buffer 1 is used by the control unit 6.
[0028]
The function of the prefetch buffer 3 can be set in an area secured in a part of the buffer memory 5. It is also possible to set the function of the prefetch buffer 3 in all or a part of a memory (not shown) outside the stream data reading device 7. In this case, the memory size of the buffer that performs the function of the prefetch buffer 3 can be made larger than the memory size of the initial prefetch buffer 3.
[0029]
Next, the operation of the first embodiment relating to the present invention will be described with reference to the flowcharts shown in FIGS.
[0030]
Reading the requested stream data from the stream data 4 means acquiring the stream data by communication from the access point.
[0031]
At the stage before Start in FIG. 2, the control unit 6 requests the stream reading unit 2 to read the stream data 4. At the same time, an area for the return buffer 1 is secured in the buffer memory 5.
[0032]
The size of the return buffer 1 is equal to the size of the requested stream data. However, the size of the requested stream data can be obtained, for example, from a storage device (not shown) in the mobile phone or from the outside (not shown) of the mobile phone. The control unit 6 issues a read request for the stream data 4 using the value.
[0033]
Next, in response to the stream data read request, the stream read unit 2 checks whether stream data is stored in the prefetch buffer 3 (S1 in FIG. 2). When stream data is stored in the prefetch buffer 3, processing is performed as follows. (The case where stream data is not stored in the prefetch buffer 3 will be described later). First, the stream data reading device 7 checks whether one type of data to be handled is determined in advance (S2 in FIG. 2). Next, if one type of data to be handled is not determined in advance, it is verified whether the stream data stored in the prefetch buffer 3 is the requested stream data (S3 in FIG. 2). The collation can be performed using predetermined identification information inserted at the beginning or in the middle of the stream data stored in the prefetch buffer 3.
[0034]
When stream data is stored in the prefetch buffer 3 and the data type handled by the stream data reading device 7 is determined in advance as one, the process of collating the stream data (FIG. 2, S3) Can be omitted.
[0035]
If all or part of the requested stream data is stored in the prefetch buffer 3 as a result of the collation of the stream data, the following is performed. The stream reading unit 2 compares the size of the return buffer 1, that is, the size of the requested stream data with the size of the stream data stored in the prefetch buffer 3 (FIG. 3, S5). The process is divided into two cases. (The case where the requested stream data does not exist in the prefetch buffer 3 as a result of the collation of the stream data will be described later).
[0036]
In the first case, that is, when the size of the stream data stored in the prefetch buffer 3 is larger than the size of the requested stream data, the stream reading unit 2 determines the requested stream data. Is obtained from the prefetch buffer 3 and transferred to the return buffer 1 (FIG. 3, S6). Thus, the stream data reading device 7 ends the requested stream data reading process. At this time, stream data acquisition work by wireless communication does not occur.
[0037]
In the second case, that is, when the size of the stream data stored in the prefetch buffer 3 is smaller than or equal to the size of the requested stream data, the stream reading unit 2 firstly All the stream data stored in the prefetch buffer 3 are transferred to the return buffer 1 (FIG. 3, S7). Next, processing related to reading of the requested stream data is performed by the following method in accordance with the size of the insufficient stream data.
[0038]
First, the size of the insufficient stream data is compared with the size of the prefetch buffer 3 (S8 in FIG. 3). Here, (the size of the shortage stream data) = (memory size of the return buffer 1) − (size of stream data first stored in the prefetch buffer 3 and transferred to the previous return buffer 1). Next, based on the result, processing is divided into two cases. That is, when the size of the insufficient stream data is smaller than the size of the prefetch buffer 3, the stream reading unit 2 newly adds the requested stream data corresponding to the size of the prefetch buffer 3 from the stream data 4. read out. Then, the stream data is stored in the prefetch buffer 3, and thereafter, the stream data having the size of the insufficient stream data is acquired from the prefetch buffer 3 and transferred to the return buffer 1 (FIG. 3, S9). Thus, the stream data reading device 7 ends the requested stream data reading process.
[0039]
Next, when the size of the insufficient stream data is larger than or equal to the size of the prefetch buffer 3, the stream reading unit 2 requests the stream data requested for the size of the insufficient stream data from the stream data 4. Is transferred to the return buffer 1 without being stored in the prefetch buffer 3 (FIG. 3, S10). Thus, the stream data reading device 7 ends the requested stream data reading process.
[0040]
In response to the stream data read request, when it is determined whether or not stream data is stored in the prefetch buffer 3 (FIG. 2, S1), the stream data is not stored in the prefetch buffer 3 Performs the following processing. That is, the stream reading unit 2 first reads the requested stream data having the size of the prefetch buffer 3 from the stream data 4 and stores it in the prefetch buffer 3 (S4 in FIG. 2). Thereafter, from FIG. 3 and S5, the processing related to the requested stream data according to the flowchart is executed in the same manner as in the above case.
[0041]
In response to the stream data read request, whether the stream data stored in the prefetch buffer 3 is the requested stream data (FIG. 2, S3), the request is made in the prefetch buffer 3. If there is no stream data, the following processing is performed. That is, the stream reading unit 2 first reads the requested stream data corresponding to the size of the prefetch buffer 3 from the stream data 4 and stores it in the prefetch buffer 3 (S4 in FIG. 2). Thereafter, from FIG. 3 and S5, the processing related to the requested stream data according to the flowchart is executed in the same manner as in the above case.
[0042]
In the first embodiment, the stream reading unit 2 calculates the size of the requested stream data from the size of the return buffer 1. However, when the stream reading unit 2 receives a request for reading the stream data 4 from the control unit 6, it is also possible to directly receive information on the size of the requested stream data. In this case, the stream reading unit 2 executes the requested stream data reading process according to the flowcharts of FIGS. 2 and 3 based on the size of the requested stream data received directly from the control unit 6. .
[0043]
At that time, it is possible for the stream reading unit 2 to secure the area of the return buffer 1 in the buffer memory 5.
[0044]
(Example 2)
Regarding the embodiment of the stream data reading device according to the present invention, a stream data reading device 17 including the prefetch buffer 13 in the stream reading unit 12 as shown in FIG. 4 is also an embodiment. The contents will be described below with reference to the drawings.
[0045]
FIG. 4 is a block diagram showing another embodiment (Embodiment 2) of the present invention, which comprises a return buffer 11, a stream read unit 12, a prefetch buffer 13, a buffer memory 15, and a control unit 16. The stream data reading device 17 of the present invention in this embodiment is present inside a mobile phone.
[0046]
4, the return buffer 11, the stream read unit 12, the prefetch buffer 13, the buffer memory 15, and the control unit 16 are the same as those described in the first embodiment except that the prefetch buffer 13 is included in the stream read unit 12. 1 is equivalent to the return buffer 1, the stream reading unit 2, the prefetching buffer 3, the buffer memory 5, and the control unit 6. The definition of the stream data 14 is also equivalent to the stream data 4 in the first embodiment.
[0047]
Next, the operation of the second embodiment of the present invention shown in FIG. 4 will be described with reference to the flowcharts shown in FIGS.
[0048]
In the present embodiment, a case will be described in which stream data is already stored in the prefetch buffer 13 and one type of data to be handled is determined in advance. However, even with the apparatus configuration of FIG. 4, the stream data reading device 17 can perform processing equivalent to the processing related to the stream data performed by the stream data reading device 7 described in the first embodiment.
[0049]
Reading the requested stream data from the stream data 14 means obtaining the stream data by communication from the access point.
[0050]
At the stage prior to Start in FIG. 5, the control unit 16 requests the stream reading unit 12 to read the stream data 14. At the same time, an area for the return buffer 11 is secured in the buffer memory 15.
[0051]
The size of the return buffer 11 is a size corresponding to the size of the requested stream data. However, the size of the requested stream data can be obtained, for example, from a storage device (not shown) in the mobile phone or from the outside (not shown) of the mobile phone. The control unit 16 issues a read request for the stream data 14 using the value.
[0052]
Next, in response to the stream data read request, the stream read unit 12 obtains the number of requested stream data from the size of the return buffer 11. Next, the value is compared with the number of stream data stored in the previously read prefetch buffer 13 (FIG. 5, S11), and the process proceeds in two cases.
[0053]
The number of requested stream data can be obtained by dividing the size of the return buffer 11 by the size of one requested stream data.
[0054]
In the first case, that is, when the number of stream data remaining in the prefetch buffer 13 is larger than the number of requested stream data, the stream reading unit 12 determines the number of requested stream data. Are obtained from the prefetch buffer 13 and transferred to the return buffer 11 (S12 in FIG. 5). Thus, the stream data reading device 17 ends the requested stream data reading process. At this time, stream data acquisition work by wireless communication does not occur.
[0055]
In the second case, that is, when the number of the stream data remaining in the prefetch buffer 13 is less than or equal to the number of the requested stream data, the stream reading unit 12 firstly All the stream data stored in the prefetch buffer 13 are transferred to the return buffer 11 (FIG. 5, S13). Next, processing related to reading of the requested stream data is performed according to the following method in accordance with the number of the insufficient stream data.
[0056]
First, the size of the insufficient stream data is compared with the size of the prefetch buffer 13 (S14 in FIG. 6). Here, (the size of the insufficient stream data) = (the memory size of the return buffer 11) − (the size of the stream data that is initially left in the prefetch buffer 13 and transferred to the previous return buffer 11). Next, based on the result, processing is divided into two cases. That is, when the size of the insufficient stream data is smaller than the size of the prefetch buffer 13, the stream reading unit 2 newly reads the requested stream data for the prefetch buffer size from the stream data 14. Then, the stream data is stored in the prefetch buffer 13, and thereafter, the stream data having the size of the insufficient stream data is acquired from the prefetch buffer 13 and transferred to the return buffer 11 (FIG. 6, S15). Thus, the stream data reading device 17 ends the requested stream data reading process.
[0057]
Next, when the size of the insufficient stream data is larger than or equal to the size of the prefetch buffer 13, the stream reading unit 12 requests the stream data requested for the size of the insufficient stream data from the stream data 14. Is transferred to the return buffer 11 without being stored in the prefetch buffer 13 (FIG. 6, S16). Thus, the stream data reading device 17 ends the requested stream data reading process.
[0058]
In the second embodiment, the stream reading unit 12 obtains the requested number of stream data from the size of the return buffer 11. However, when the stream reading unit 12 receives a request to read the stream data 14 from the control unit 16, it is also possible to directly receive information on the number of requested stream data. In this case, the stream reading unit 12 executes the requested stream data reading process according to the flowchart of FIG. 5 based on the number of requested stream data received directly from the control unit 16.
[0059]
At that time, it is possible for the stream reading unit 12 to secure the area of the return buffer 11 in the buffer memory 15.
[0060]
In the first and second embodiments, a process for wirelessly reading the deficient or all requested stream data from the stream data 4 and 14 is as follows. The stream reading units 2 and 12 request communication to an access point from a radio unit (not shown) responsible for transmission / reception of radio signals in the mobile phone. When the wireless unit establishes a connection wirelessly, the stream reading units 2 and 12 request the access point to transmit the shortage or all the requested stream data through the wireless unit. At the time of the request, the stream reading units 2 and 12 send information necessary for specifying the requested stream data to the access point. The access point transmits the shortage or all the requested stream data in response to the request. Stream reading units 2 and 12 read data from the head of the shortage or all requested stream data received by the radio unit. The end of data is performed by the identification information included at the end of the data.
[0061]
In the first and second embodiments, the stream data stored in the prefetch buffers 3 and 13 or the stream data acquired by wireless communication includes identification data at the beginning or middle of the stream, or It is possible to distinguish between stream data by putting identification information in the head or header part.
[0062]
In addition to the above example, this technology can be used for PDC, PHS, and other devices used for mobile communication that perform processing for reading stream data by communication.
[0063]
【The invention's effect】
According to the present invention, when reading stream data, the time (overhead) spent for processing for accessing the stream data of the stream reading unit can be reduced, and the processing efficiency can be improved.
[0064]
In addition, according to the present invention, the stream data in the prefetch buffer can be used when reading the stream data, so that the stream data can be acquired quickly and the time required for reading the stream data can be shortened.
[0065]
The present invention can reduce overhead and improve the processing efficiency, particularly when read requests for a small amount of stream data smaller than the size of the prefetch buffer are continuously generated.
[0066]
The present invention makes it possible to quickly acquire stream data because the stream data in the prefetch buffer can be used, particularly when a read request for a small amount of stream data smaller than the size of the prefetch buffer occurs continuously. And the time required for reading the stream data can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a part of a flowchart showing an operation of the stream data reading device in FIG. 1;
FIG. 3 is the remaining part of the flowchart showing the operation of the stream data reading device in FIG. 1;
FIG. 4 is a block diagram showing another embodiment of the present invention.
FIG. 5 is a part of a flowchart showing an operation of the stream data reading device in FIG. 4;
6 is the remaining part of the flowchart showing the operation of the stream data reading device in FIG. 4;
[Explanation of symbols]
1 Return buffer
2 Stream reading part
3 Prefetch buffer
4 Stream data
5 Buffer memory
6 Control unit
7 Stream data reading device
11 Return buffer
12 Stream reading unit
13 Prefetch buffer
14 Stream data
15 Buffer memory
16 Control unit
17 Stream data reading device

Claims (9)

A return buffer as the specified location, and
A read-ahead buffer;
In response to the stream data read request, the requested stream data is read from the stream data, the requested stream data read to the prefetch buffer is stored, and the requested stream data or the prefetch buffer is stored. A stream reading unit comprising means for transferring the requested stream data to the return buffer ;
Was immediately Bei,
The stream reading unit
When the stream data is insufficient with only the stream data transferred to the designated location, the requested stream data corresponding to the size of the prefetch buffer is read again from the stream data, and the requested stream is read. A stream data reading device that stores data in the prefetch buffer and transfers insufficient stream data to the designated location from the requested stream data stored in the prefetch buffer . A read-ahead buffer;
In response to the stream data read request, the requested stream data is read from the stream data, the requested stream data read to the prefetch buffer is stored, and the requested stream data or the prefetch buffer is stored. A stream reading unit comprising means for transferring the requested stream data to a designated location ;
Bei to give a,
The stream reading unit
When the stream data is insufficient with only the stream data transferred to the designated location, the requested stream data corresponding to the size of the prefetch buffer is read again from the stream data, and the requested stream is read. A stream data reading device that stores data in the prefetch buffer and transfers insufficient stream data to the designated location from the requested stream data stored in the prefetch buffer . A return buffer as the specified location, and
A read-ahead buffer;
In response to the stream data read request, the requested stream data is read from the stream data, the requested stream data read to the prefetch buffer is stored, and the requested stream data or the prefetch buffer is stored. A stream reading unit comprising means for transferring the requested stream data to the return buffer ;
Was immediately Bei,
The stream reading unit
When the stream data is insufficient with only the stream data transferred to the designated location, the insufficient stream data is read again from the stream data, and the read insufficient stream data is transferred to the designated location. stream data read apparatus for. A read-ahead buffer;
In response to the stream data read request, the requested stream data is read from the stream data, the requested stream data read to the prefetch buffer is stored, and the requested stream data or the prefetch buffer is stored. A stream reading unit comprising means for transferring the requested stream data to a designated location ;
Bei to give a,
The stream reading unit
When the stream data is insufficient with only the stream data transferred to the designated location, the insufficient stream data is read again from the stream data, and the read insufficient stream data is transferred to the designated location. stream data read apparatus for. The prefetch buffer is included in the stream read unit;
The stream data reading device according to claim 1, wherein The stream data reading device includes:
A buffer memory for transferring the requested stream data read by the stream reading unit;
The return buffer is a memory area secured in the buffer memory when a stream data read request is made.
6. The stream data reading device according to claim 1, wherein the stream data reading device is any one of the above. A prefetch buffer different from the prefetch buffer can be set inside the buffer memory.
The stream data reading device according to claim 6, wherein: The size of the prefetch buffer is variable;
8. The stream data reading device according to claim 1, wherein the stream data reading device is any one of the above. The stream data reading device is included in devices used for PDC (Personal Digital Cellular), PHS (Personal Handy phone System), and other mobile communications, and receives stream data by radio.
9. The stream data reading device according to claim 1, wherein the stream data reading device is any one of the above.

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