JPH06326856A - Data recorder and its method - Google Patents

Abstract

PURPOSE:To transfer picture data efficiently in a short time by comparing a characteristic of a picture itself with information relating to an equipment of transfer destination and converting stored picture data into picture data corresponding to a specification or a function of the equipment of the transfer destination. CONSTITUTION:A picture whose transfer is requested is specified by a picture ID. Corresponding picture data are read from a picture data storage section 160 through a picture file management section 165 and stored in a picture data temporary storage section a170. On the other hand, characteristic information of the corresponding picture is inputted to a conversion method selection section 140 from a picture characteristic management table 135 by the picture ID. A conversion method selection section 140 compares number of photoelectric conversion elements and number of colors of the picture for the equipment of a transfer destination with those of an object picture to specify the conversion method absorbing the difference. A picture conversion processing section 175 applies required conversion to the picture data stored in the picture data temporary storage section a170 according to the decided conversion method to provide an output to a picture data temporary storage section b180.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording and transfer of data used in a system for transferring data between a plurality of information processing devices, and in particular, there is a need for some kind of data transfer between recorded data and data required at a transfer destination. The present invention relates to an information processing apparatus (data recording apparatus) and method for performing most efficiently a series of processes from data reading to processing and transfer when conversion or data processing is required.

[0002]

2. Description of the Related Art When image data is handled in an information processing device such as a computer, the number of pixels of an image that can be displayed and the number of colors that can be used are limited by the specifications of the device to be displayed. When connecting multiple devices via a network and transferring the stored image data to another device for display, if the specifications of the stored image data and the specifications of the device to be displayed are different, generally In the display device as a part of the display process, the number of pixels and the number of colors to be displayed are converted according to the specifications of the device on the display side.

[0003]

When a plurality of devices are connected to transfer data, the stored data may not match the specifications of the device requesting the data.
Especially when many devices are connected via a communication network,
Functions and specifications often differ between devices.

For example, when displaying accumulated image data, it is necessary to convert the number of pixels when the number of pixels of the image data is different from the number of pixels that can be displayed by the device. Regarding this conversion, it is necessary to know the number of pixels of the stored image and the specifications of the receiving side device used for display,
Conventionally, in most cases, this processing is performed in the receiving side device.

However, if the receiving side device performs the conversion, it takes a long processing time when the receiving side processing speed is much lower than the processing speed of the transmitting side device which has stored the image, for example. Also, when the number of pixels is converted in the receiving device,
When an image with a large number of pixels is transferred and displayed on a device with a low resolution, a large amount of image information must be transferred through the network although it is not displayed.
It reduces the efficiency of network usage. Further, it is necessary for the operator to grasp the number of pixels of each image and the number of pixels of the display device and perform the conversion process.

Further, regarding the processing in which various methods such as the encoding method exist, when the data is accumulated by the method which cannot be supported by the receiving side, the operator individually performs the decoding processing in the server. There are also problems such as having to instruct execution.

In the present specification, a device for accumulating and transferring an image is hereinafter referred to as a server, and a receiving device for issuing a transfer request and displaying the image data sent is called a client.

[0008]

In order to solve the above-mentioned problems, in the present invention, both the server and the client are provided with means for performing the necessary conversion processing, and when the conversion processing is executed by the server Means for calculating the processing time required by the client, means for calculating the processing time required when each connected client performs the above conversion processing, and management of image specifications of images that can be displayed by the client. And a means for managing the specifications of the requested image, and in the case where an image transfer request is made from the receiving side device, the conversion that needs to be executed from the managed information and the conversion It has a means for determining the procedure to be executed at the highest speed.

[0009]

[Operation] When a data transfer request is made by a client, the server reads the corresponding image data from a data storage medium such as a magnetic disk, and at the same time manages information relating to the number of pixels and the number of colors of the corresponding image data. Read from a table. Further, information regarding the number of pixels and the number of colors that can be displayed by the client that issued the transfer request is also read from the management table or the like.

From these two kinds of information, the contents of conversion necessary for displaying the image for which a transfer request has been made on the corresponding client, for example, the necessity of resolution conversion processing for changing the number of pixels and its magnification, are found, Each parameter can be calculated.

When the content of the conversion that needs to be executed is known, the processing time required when each processing is executed by both the server / client is calculated. At this time, the required time on the server side changes from moment to moment depending on the number of connected clients, so it is calculated including the occupation rate of the arithmetic unit. Also, the transfer rate of the network at each time point is calculated in the same manner.

When all the above information are gathered, a procedure for completing the corresponding processing and data transfer in the server in the shortest processing time is determined. On this occasion,
It is necessary to include not only that the processing time is short but also that the transfer time varies depending on the transfer amount of moving data in the network.

As a result, the operator can receive and display the image data in a short time even if he / she does not know the information about each client or the status of the network.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of means for realizing the present invention will be described below with reference to the drawings. FIG. 1 shows the basic configuration of the device according to the present invention. First, for simplification, a case where the server and the client are one-to-one will be described as an example. For the sake of explanation, the execution part of each process is described as shown in the figure, but in the actual configuration, it is also possible to realize it by software of a computer.

In the figure, (100) indicates a server, and (200) indicates a client. The image data is stored in an image data storage unit (16) using a magnetic disk or the like connected to the server.
0), is transferred via the communication line (10) in response to a request from the client, and is displayed on the display device (270) of the client.

Each part will be described in order from the server side according to the drawing. The communication control unit (110) inputs / outputs data via a communication line (10) according to a procedure determined in advance. The data input to the server side is a client identifier that identifies a connected client and an image ID that identifies an image to be transferred. On the other hand, the information output from the server to the client is the requested image data, the instruction of the content of conversion to be performed on the client side, and the conversion parameter.

The client identification section (120) identifies the client to be transferred by the client identifier sent from the client. When the client is specified, the specification of the corresponding client is converted from the client management table by the ID, and the conversion content determination unit
0), and the corresponding information is also output from the processing time management file in which the time required for processing for each conversion content method is accumulated.

The image requested to be transferred is specified by the image ID. The corresponding image data is read from the image data storage unit (160) through the image file management unit (165) and recorded in the image data temporary storage unit (a) (170). On the other hand, the characteristic information of the corresponding image is also input to the conversion content determination unit (140) from the image characteristic management table (135) based on the image ID.

In the result conversion method selection unit (140), the conversion processing required to compare the difference between the number of pixels and the number of colors that can be handled by the target image and the client of the transfer destination and absorb it, for example. You can judge the contents of.

When handling an image in the system as described in this specification, there are the following eight items as examples that may require conversion at the time of data transfer.

(1) Resolution (2) Number of display colors (3) Color space (4) Encoding method (5) Encoding parameters (6) File format (7) MSB-LSB direction (8) Block data transfer Information about how much processing time is required can be obtained from the client specified as the order-determined conversion content by the processing time management table (153) when the server and the client perform individual processing. The conversion procedure determination unit determines whether it is appropriate to perform each process by the server or the client based on the time required for each of the above conversions and the time required for data communication. Here, the time required for communication is obtained from the amount of data output from the server and the transfer speed of the communication line. The transfer speed is calculated using the method already used in general computer networks, but if the speed at which the image transfer request is transferred is detected and used, connect multiple clients, It is possible to dynamically support a system in which the load on the network changes every moment.

The image conversion control section (a) (155) drives the image conversion processing section (175) according to the determined conversion procedure in the server. The image conversion processing unit (175) is an image data temporary storage unit (a) (17).
The image recorded in 0) is subjected to necessary conversion and output to the image data temporary storage section (b). Here, the two image data temporary storage units (170) and (180) can be configured by the same memory.

On the other hand, the contents of the conversion determined to be performed by the client are delivered to the client via the communication line. On the client side, the image conversion control unit (b)
(230) drives the image conversion processing unit (245) based on the conversion instruction from the server.

The image data that has been converted on the server is transferred from the communication control unit to the image data temporary storage unit (c) (240) on the client through a predetermined procedure.

The transferred image data is subjected to conversion processing on the client side by the image conversion processing unit (245) and output to the image data temporary storage unit (d) 250).
Further, by being transferred to the image display memory (260), it is displayed on the image display unit (270). Here, as in the case of the server, the two image data temporary storage units (240) and (250) can be configured by the same memory.

It is to be noted that the image transfer request issuing unit (220) on the client first executes the specification of the image to the server to request the transfer. For example, the operator inputs the information for specifying the required image by a known input means such as a keyboard, so that the image transfer request issuing unit (2
By transferring the image ID to the server from 20),
The image request is fulfilled.

Next, the flow of a series of processes will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram illustrating the flow of processing on the client side. First, an image transfer request is issued by (310). After that, the process moves to the server (320), and the process returns to the client again at the time when the image data is transferred (330). The transferred image data is temporarily stored. Further, the contents of the conversion process to be performed on the client side and the parameters required there are sent from the server as image conversion control information (340).

Here, if all the necessary conversions are completed on the server side, the client transfers the data to the image display memory (380) without executing the conversion, and the image is displayed.

On the other hand, when processing is required on the client side, the image conversion processing unit is activated according to the image conversion control information (351), and conversion processing is performed on the temporarily stored image (352). ), And the result is (250) in FIG.
The image data is temporarily stored in the image data temporary storage unit (d) (353) and transferred to the image display memory to complete the display.

Next, the flow of processing in the server will be described with reference to FIG. Upon receiving (410) the image transfer request from the client, the server reads the target image file from the image ID. At the same time in (420) the size of the corresponding image and the number of colors used,
Alternatively, the information of the corresponding image is read from the image characteristic management table in which the color system and the presence / absence of encoding are recorded. However, the characteristics of each image described here are often recorded in the image file itself as, for example, header information. In that case, it is not necessary to save another management file. On the other hand, the client that issued the transfer request in the course of the communication procedure is specified. Therefore, at the stage of (425) in the figure, the identification of the client is completed and the corresponding client information is read (430). The contents of the client information will be described later in detail. By comparing the read information of the client with the information of the image, it is possible to determine the content of the necessary conversion process at the stage of (435).

When the content of conversion is determined, the time required for each conversion processing when each processing is executed by the client and the server can be obtained from the processing time management table (440), and the data flowing on the communication line can be obtained. Since the amount is determined, the time required for data transfer is known.

Optimal allocation of conversion processing can be determined (450) by calculating and comparing the total processing time when each processing is executed by the client and the server, and selecting the smallest combination. .

When calculating the required time here, it is necessary to consider the occupation rate of the server as the processing capacity of the server. Also, since the transfer capacity of the communication line is constantly changing,
By making a correction using the value of the transfer speed obtained by a known means when the image transfer is requested, the accuracy of the judgment can be improved.

Next, of the conversion processing, the portion to be executed by the client is instructed to the client side (460) and the conversion processing to be executed by the server is executed (470).

After the conversion, the converted image data is transferred to the client (475), but this transfer can be partially executed before the conversion is completely completed.

Next, a method of determining conversion contents and a conversion procedure, which is a feature of the present invention, will be described. Since the conversion content absorbs the difference between the specifications of the client and the specifications of both, it is necessary to compare the specifications of both.

Table 1 is an example of the client management table recorded in the server.

[0038]

[Table 1]

In addition to the name of the client, the hardware specifications of the device such as the number of pixels and the number of colors that the client can display are registered for each device ID. It also records the functions that can be executed by the software installed in each device.
In this case, it means that the image data needs to be transferred in the form of the original image because the device having the ID 1 cannot execute the code decoding process at all.

On the other hand, information relating to each image data side is similarly managed on the server side. Table 2 is an example of an image management table for that purpose.

[0041]

[Table 2]

The number of pixels and the number of colors of each image, the presence / absence of encoding, and the method thereof will be described. For image data,
A method of accumulating these related information as header information of each image data is also widely used, and in that case, the same effect can be obtained without accumulating such an independent table.

If the resolution and the number of colors that can be displayed on the client side and the resolution and the number of colors of the image data to be displayed are known, the contents of the processing required to display a certain image on the client can be determined.

For example, when displaying the image data of 1280 × 960 pixels on the client whose device ID is 1, the horizontal and vertical directions are 1
This means that it is necessary to apply the reduction processing to / 2. Further, when displaying a full-color image of 8 bits each for RGB on a display device of 256 colors, 24 bits to 8 bits are displayed.
A conversion called color reduction processing is required.

A process of determining what kind of conversion is necessary will be described with reference to FIG. This is (435) in FIG.
It corresponds to the contents of the part described as. Here, as an item to be considered for simplification, the case where only the resolution, the number of colors, and whether or not it is the code data are determined is taken as an example. Including.

First, at (610) in the figure, the display pixel number of the client read from the client management table is compared with the pixel number of the corresponding image data obtained from the image management table. If there is a difference between the two, it is necessary to perform resolution conversion processing on the accumulated image data to obtain image data that matches the number of display pixels of the client. When resolution conversion is required (612)
A flag for instructing the execution of the resolution conversion process is set as shown in, and the magnification is calculated from the comparison of both. This magnification and the size of the image data are used as parameters ((17)
The resolution conversion process is executed by the image conversion unit shown in 5) or (245).

Next, it is described in the image management table whether or not the accumulated image data is the code data having the code feature, and if it is the code data, which method is used for the encoding. Judging from the matter (620).
If the data is coded data, a decoding process flag is set to indicate that the decoding process needs to be performed in the process up to image display. Here, since there are a plurality of encoding methods, the decoding process flag includes means for identifying the decoding method.

Further, the number of colors that can be displayed by the corresponding client is compared with the number of colors of image data, and it is determined whether or not it is necessary to execute color conversion such as color reduction processing or color table reconstruction. Stand up. At this time, the flag includes a means for specifying the contents of conversion, and the parameter is set at this point if necessary.

Next, a method of determining a conversion procedure for determining which of the server and the client should execute each necessary conversion process will be described. This process is (45) in FIG.
It is the content of the part described as 0).

The processing flow will be described with reference to FIG. Here, a case where resolution conversion and color number conversion are performed will be described as an example. First, the required time for the conversion process that needs to be executed in the server and the corresponding client is read from the conversion required time calculation table. Table 3 shows an example of the conversion time calculation table.

[0051]

[Table 3]

The conversion time calculation table manages the time required when each process is executed in the server and each client. Since the time required for image processing generally depends on the content of the input / output image, particularly the number of pixels, the time required here is the number of input pixels (x1, y1) or the number of output pixels (x2, y).
It is a function of 2).

Next, from the read conditions, that is, the requested image size and the number of pixels of the display device, the required time for performing the corresponding processing in the server and the client is calculated. At this time, in actual use, a plurality of clients may simultaneously connect to the server and request processing. In that case, since the processing capacity of the server depends on the occupation rate of the arithmetic processing unit, it is necessary to consider the occupation rate at each time point also in the calculation of the required time. A known method is used as a method of detecting the occupation rate of the arithmetic processing unit in the server to which the plurality of clients are connected.

Further, the time required to transfer the data from the server to the client is estimated. This is calculated from the value of the transfer speed of the command, which was found when the image request was sent from the client to the server, and the amount of data when the image was transferred.

By substituting each calculated required time into each item shown in Table 4, for example, a combination having the shortest required time is selected, and at that time, which conversion process belongs to which server or client? Optimize the sharing by judging.

[0056]

[Table 4]

In this example, the total required time is used as a criterion for determination, but it is also possible to use the load of the communication line as a criterion, or the load reduction on the client side as a criterion.

By combining the above means, when the image data stored in the server is transferred in accordance with the request from the client, the processing and data transfer adapted to the number of pixels and the number of expressed colors of the client can be performed at the highest speed. Became possible.

As an application example derived from the above method, there is a case where a client is newly connected on the line and management information such as its specifications and processing capability is not yet recorded in each management table in the server. An example of the flow of processing on the server side when an image transfer request comes from this client will be described with reference to FIG.

The process is performed in the same manner as in FIG. 3, but is executed in the form of an exception process when the client ID is detected and the corresponding client is not registered in the client management table (432). In this case, a specific value is set in advance for the number of pixels to be output and the number of display colors, and conversion for that value is executed (433). All conversion processing is handled as being executed on the server side. As a result of this, FIG.
The deciding part of the conversion procedure indicated by is unnecessary, and no conversion instruction is given to the client. When a new client is added, the optimum processing share described above can be used by registering each management table in the server.

Next, as an application example of the present invention, a case where the conversion process is performed only on the server side will be described with reference to FIGS. 7 and 8. In this case, only the automation of the conversion process is realized from the information of the client and the image data. When multiple clients are requesting one server at the same time via the communication line, efficiency can be improved by sharing part of the processing on the client side, but when the number of clients is small The server can also do all the work.

FIG. 7 is a diagram for explaining the operation flow on the client side and corresponds to FIG. In this case, the client simply requests the server to transfer an image, receives the image data that has been converted from the server, and displays it.
On the other hand, the server operates according to the flow shown in FIG. 8, and the determination part of the conversion procedure described as (450) in FIG. 3 and the image conversion processing instruction at the client can be deleted.

In this specification, for simplification of explanation,
The case where a device for storing images exists separately from the conversion device which is the center of the present invention has been described. However, by providing the storage device itself with the functions or means described here, both can be combined into a single device. Can be achieved with.

In the present specification, for the sake of explanation, the case where it is realized by the configuration of each part of the apparatus has been described. However, the same function as that of the apparatus described in this specification is realized by software using, for example, a personal computer or a workstation. You can also The flow of processing in that case is as described in the present specification, but the inside of the device is composed of a CPU and a memory.

[0065]

According to the present invention, in a system in which a plurality of computers are connected via a network, when the image data stored in a part of the system is transferred to another device for use, the transfer destination device is used. It is possible to realize a system in which the operator can perform image conversion according to the specifications without being aware of it, and when performing conversion and transfer, the conversion can be performed by the procedure with the highest efficiency of the entire processing including transfer. .

[Brief description of drawings]

FIG. 1 is a diagram illustrating a basic configuration of the present invention.

FIG. 2 is a diagram illustrating the overall flow of image conversion in this system.

FIG. 3 is a diagram illustrating a flow of processing in a server part.

FIG. 4 is a diagram illustrating a flow of processing for determining what kind of conversion is necessary.

FIG. 5 is a diagram illustrating a method of determining a division of where to execute each conversion.

FIG. 6 is a diagram illustrating a flow of processing when a transfer request is received from an unknown client.

FIG. 7 is a diagram illustrating a process in the case where all conversion pairs are executed on the server side.

8 is a diagram for explaining the flow on the server side in the upper body of FIG.

[Explanation of symbols]

100 ... Server, 120 ... Client Identification Unit, 125
... client management table, 130 ... image ID reading unit, 135 ... image characteristic management table, 140 ... conversion method selection unit, 150 ... conversion procedure determination unit, 153 ... processing time calculation table, 155 ... image conversion control unit (a) , 160
6 ... Image data storage unit, 165 image file management table, 170 ... Image data temporary storage unit (a), 175 ... Image conversion unit (a), 180 ... Image data temporary storage unit (b), 200 ... Server, 220 ... Image transfer request issuing unit, 230 ... Image conversion control unit (b), 240 ... Image data temporary storage unit (a), 245 ... Image conversion unit (b), 25
0 ... Image data temporary storage unit (b), 260 ... Image display memory, 270 ... Image display unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H04L 12/58 H04N 1/41 Z 9070-5C 1/46 C 9068-5C 7/01 Z 6942- 5C (72) Inventor Eiichi Hatano 1-280 Higashi Koigokubo, Kokubunji City, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (16)

[Claims] 1. A data recording device for accumulating image data and transferring it to another external device, means for accumulating information about characteristics of the image itself and information about a device to which the data is transferred, and A means for converting the image data stored in the image data into image data according to the specifications or functions of the transfer destination device, a means for comparing the characteristics of the image itself with information on the transfer destination device, and a conversion method for the comparison result. A data recording device comprising means for determining. 2. A data recording device for accumulating image data and transferring it to another external device, comprising means for accumulating the number of pixels of the image itself, and the number of pixels that can be displayed by the device to which the data is transferred. A means for accumulating, a means for converting the number of pixels of the accumulated image data into a number of pixels that can be displayed by the transfer destination device, and the number of pixels of the accumulated image and the number of pixels of the display device are compared. A data recording device comprising means and means for determining a conversion method or a magnification as a result of the comparison. 3. A data recording device for accumulating image data and transferring it to another external device, which is a means for accumulating a display color used by the accumulated image and a data transfer destination. A means for accumulating the number of colors that can be displayed by the device, a means for converting the number of colors of the accumulated image data into the number of colors that can be displayed by the transfer destination device, and the above-mentioned accumulated images. A data recording device comprising means for comparing the number of colors and the number of colors that can be expressed by the display device, and means for determining a conversion method or a parameter as a result of the comparison. 4. A data recording device for accumulating image data and transferring it to another external device, means for accumulating an encoding method applied to an accumulated image,
A means for storing the encoding method that can be restored by the device to which the data is transferred, and if the encoding method of the stored image data cannot be handled by the transfer destination, restore the image data once and transfer it again. A data recording device, characterized in that the data recording device has means for carrying out re-encoding by a suitable encoding method previously. 5. A data recording device for accumulating image data and transferring it to another external device, means for accumulating the processing speed of the image data accumulating device and the processing speed of the transfer destination device, and the image recording device. A data recording device having means for executing conversion processing when transferring data, and means for judging whether the conversion processing is executed by an image data storage device or a transfer destination. 6. The processing speed of the accumulated storage device and the transfer destination device as a means for determining which of the image data storage device and the transfer destination executes the conversion process according to claim 5. From the above, a data recording device having means for calculating a required time when the conversion is executed in each device, and means for selecting a combination having the minimum required time. 7. The method according to claim 5, wherein the amount of data flowing on a communication line connecting both of the devices is minimum as means for determining whether to execute the conversion process by a storage device or a transfer destination of the image data. A data recording device having means for selecting a combination. 8. The processing speed of the accumulated storage device and the transfer destination device as a means for determining which of the image data storage device and the transfer destination executes the conversion process according to claim 5. To calculate the required time when the conversion is performed by each device, the means to calculate the transfer time on the communication line connecting both devices in each combination, and the sum of the required time and the transfer time is minimized. A data recording device having means for selecting a combination. 9. A data recording method for accumulating image data and transferring the same to another external device, wherein information on characteristics of the image itself and information on a device to which the data is transferred are accumulated and accumulated. When converting image data to image data according to the specifications or functions of the transfer destination device,
A data recording method, comprising: comparing the characteristics of the image itself with information about the transfer destination device to determine a conversion method as a result of the comparison. 10. A data recording method for accumulating image data and transferring it to another external device, wherein the number of pixels of the image itself is accumulated, and further the number of pixels that can be displayed by the device to which the data is transferred is accumulated. Incidentally, at the time of image transfer, the number of pixels of the stored image data is converted into the number of pixels that can be displayed by the transfer destination device, and the number of pixels of the stored image and the pixel of the display device are converted. A data recording method, wherein the numbers are compared and a conversion method or a magnification is determined as a result of the comparison and the conversion is performed. 11. A data recording method for accumulating image data and transferring it to another external device, detecting the display color used by the accumulated image and the number of colors that can be displayed by the device to which the data is transferred. Then, in order to convert the number of colors of the accumulated image data to the number of colors that can be displayed by the transfer destination device and transfer it, the display colors used in the above image and the number of colors that the display device can express And a conversion method is executed as a result of the comparison, or a parameter is determined and conversion processing is executed. 12. A data recording method for accumulating image data and transferring the image data to another external device, which is a device as a data transfer destination by detecting an encoding system applied to the accumulated image. Detects a coding method that can be restored, and if the coding method of the accumulated image data cannot be handled by the transfer destination, once restores the image data and then re-encodes with the coding method suitable for the transfer destination. A data recording method, characterized in that the data is transferred after being subjected to the above. 13. A data recording method for storing image data and transferring it to another external device, comparing the processing speed of an image data storage device with the processing speed of a transfer destination device, and transferring the image data. Determine whether to execute the conversion process to be performed when the image data storage device or transfer destination,
A data recording method characterized by performing conversion processing according to the judgment. 14. The method according to claim 13, wherein the processing speed of the accumulated storage device and the transfer destination device is used as a method of determining which of the image data storage device and the transfer destination executes the conversion process. The data recording method is characterized by calculating the required time when the conversion is executed by each device, and selecting the combination that minimizes the required time. 15. The method according to claim 13, wherein a method for determining whether to execute the conversion processing by the image data storage device or the transfer destination is that the amount of data flowing on a communication line connecting both devices is minimum. A data recording method, characterized in that the following combination is selected. 16. The method according to claim 13, wherein the processing speed of the accumulated storage device and the transfer destination device is used as a method for determining which of the image data storage device and the transfer destination executes the conversion process. Calculate the required time when the conversion is performed by each device, calculate the transfer time on the communication line connecting both devices in each combination, and select the combination that minimizes the sum of the required time and the transfer time. A data recording method characterized by the above.