JPH10285240A - Data communication equipment and its method, data communication system and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit/receive data in a form of compressed data to the utmost. SOLUTION: A transmission source 101 checks whether or not a coding system of a transmission destination 102 is coincident with that of the source before the transmission of data. When they are coincident, the source sends compression data and sends data after decoding when dissident. Or when the transmission destination 102 has a capability of changing its decoding system depending on a program, the transmission source 101 sends a decoding program before data transmission to the transmission destination 102 and then sends the compression data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication bus or the like capable of communicating control signals and data in a mixed manner. TECHNICAL FIELD The present invention relates to a data communication apparatus and method for performing data communication by using a data communication system and a storage medium.

[0002]

2. Description of the Related Art Among personal computer peripheral devices, hard disk drives and printers are the most frequently used, and these peripheral devices are digital interfaces (hereinafter referred to as digital I / F) which are typical general-purpose interfaces for small computers. The connection between personal computers is made by using SCSI or the like, and data communication is performed.

A recording / reproducing device such as a digital camera or a digital video camera is also one of the peripheral devices used for inputting an image to a personal computer (hereinafter, PC).
One. In recent years, the technology in the field of importing images such as still images and moving images taken by a digital camera or video camera to a PC and storing them on a hard disk or editing them on a PC and then color printing with a printer has been advanced. is increasing.

[0004] When outputting the captured image data from a PC to a printer or a hard disk, the above-mentioned SCSI is used.
Data communication is performed via the like. In such a case, in order to send information having a large data amount such as image data, such a digital I / F has a high transfer data rate.
And a versatile one is needed.

FIG. 3 shows a conventional digital camera,
FIG. 2 shows a block diagram when a PC and a printer are connected.

In FIG. 3, reference numeral 31 denotes a digital camera, 32 denotes a personal computer (PC), and 33 denotes a printer. Further, 34 is a memory which is a recording unit of the digital camera, 35 is a decoding circuit for image data, 36 is an image processing unit, 37
Is a D / A converter, 38 is a viewfinder (EVF) as a display unit, and 39 is a digital I / O of a digital camera.
Unit, 40 is a digital I / O unit with a PC digital camera,
41 is an operation unit such as a keyboard and a mouse, 42 is a decoding circuit for image data, 43 is a display, 44 is a hard disk device, 45 is a memory such as a RAM, and 46 is an MP of an arithmetic processing unit.
U and 47 are PCI buses, 48 is a digital I / F SCSI interface (board), 49 is a PC 32 and a SCSI interface of a printer 33 connected by a SCSI cable,
50 is a memory, 51 is a printer head, 52 is a printer controller of a printer control unit, and 53 is a driver.

An image picked up by the digital camera 31 is transferred to a PC 32.
Will be described below, and a procedure for outputting from the PC 32 to the printer 33 will be described. When the image data stored in the memory 34 of the digital camera 31 is read, one of the read image data is decoded by the decoding circuit 35,
Image processing for display by the image processing circuit 36 is performed.
It is displayed on the EVF 38 via the / A converter 37. On the other hand, the digital signal is transmitted from the digital I / O unit 39 to the digital I / O unit 40 of the PC 32 via a cable for external output.

In the PC 32, a PCI bus 47 is used as a bus for mutual transmission, and image data input from the digital I / O unit 40 is stored in the hard disk 44 when stored, and is decoded by the decoding circuit 42 when displayed. Memory 45
Is stored as a display image, converted into an analog signal on the display 43, and displayed. Operation input such as editing at the PC 32 is performed from the operation unit 41, and the entire processing of the PC 32 is performed at the MPU 46.

When printing out an image, a PC
Image data is transmitted on a SCSI cable from a SCSI interface board 48 in the SCSI 32, received by a SCSI interface 49 of the printer 33, formed as a print image in a memory 50, and controlled by a printer controller 52 and a printer head 51 and a driver. 53 working, memory
Print the print image data read from 50.

The above is the procedure up to the point where the conventional image data is taken into the PC or printed.

As described above, conventionally, each device is connected to a PC serving as a host, and image data captured by a recording / reproducing apparatus is printed via the PC.

[0012] Also, there are diversified methods for compressing video data. JPEG is known as a method for compressing still images, and MPEG is known as a method for compressing moving images. In addition, a home digital VTR (DVC) uses a unique compression method combining VLC and DCT. As described above, various compression schemes are categorized for each device or each type of data.

[0013]

However, as the problems of the digital interface mentioned in the above conventional example, SCSI has a low transfer data rate, a thick cable for parallel communication, and a peripheral device to be connected. There are restrictions on types, numbers, connection methods, etc., and inconveniences in many aspects have been pointed out.

[0014] Further, most of ordinary home PCs are PCs.
In many cases, a connector for connecting SCSI or other cables is provided on the back of the device, and the shape of the connector is large. Even when connecting a portable or portable device such as a digital camera or a video camera which is not usually fixed, the device must be connected to the rear connector of the PC, which is very troublesome.

In general, many peripheral devices are connected to a personal computer. In the future, the types of peripheral devices will increase, and the PC will be improved by improving the I / F.
It is expected that not only peripheral devices but also many digital devices can be connected via a network. While this is very convenient, communication with a very large amount of data is frequently performed depending on the device, so that the network is congested and communication between other devices in the network is affected. It can be brought. For example, when the user wants to print an image continuously or quickly, the data communication between the PC and the printer is
Communication between devices that the user is not conscious of may affect the entire network or the PC serving as a host, and thus may not be successful, and the image printing may not be executed normally or may be delayed. in this way,
Load on PC due to network congestion, PC
There is also a problem such as data communication depending on the operation status of.

Further, when a plurality of devices are connected to a network, compressed data that cannot be decompressed may be erroneously transferred or may be decompressed at the transfer destination due to the difference in the data compression method used for data transfer between certain devices. There is a problem in transfer operation and efficiency, such as transfer of uncompressed data when possible.

The present invention has been made in order to solve the above-mentioned conventional problems, and has been made in consideration of the conventional digital I / O.
/ F general-purpose digital I / F (for example, IE
EE1394-1995 high-performance serial bus) to realize data communication between devices when a PC, a printer, other peripheral devices, a digital camera or a digital VTR recording / reproducing device are connected in a network configuration, and the recording / reproducing device. Import video data, etc. to a PC, and transfer video data directly to a printer for printing.
An object is to realize so-called direct printing.

More specifically, based on information such as whether the transfer destination device has decoding means, and the type and configuration of the decoding means provided, the encoded data as compressed data to be transferred remains unchanged. It is an object of the present invention to perform data transfer according to the configuration of a transfer destination by transmitting the selected data or transmitting the data after decoding the encoded data.

Further, by transferring program information for decoding data to the transfer destination device, even if the transfer destination device does not have decoding means suitable for decoding data, the encoded information to be transferred can be transferred. An object of the present invention is to enable decoding of data by a transfer destination device.

[0020]

To achieve the above object, the present invention has the following arrangement. That is, encoding means for encoding data in a predetermined manner, a first mode for transmitting data as it is encoded, and a second mode for decoding and transmitting encoded data. Transmitting means for transmitting data to the communication destination node by any one of the methods described above. If the coding method by the coding means is a coding method corresponding to the decoding means provided in the communication destination node, the first In this mode, data is transmitted in the second mode if it does not correspond.

[0021] Also, encoding means for encoding data in a predetermined manner, transmission means for transmitting program information including a decoding procedure for decoding the data encoded by the encoding means, Second transmitting means for transmitting the encoded data.

A data communication system comprising a first node and a second node connected to each other and comprising an encoding means, wherein the second node decodes the data encoded by the first node. The first node transmits the data encoded by the encoding means to the second node, and the second node transmits the data encoded by the first node. If there is no means to decrypt
The first node decodes the encoded data and sends the data to a second node.

Also, a first node comprising an encoding unit and a storage unit for storing program information for decoding data encoded by the encoding unit, and a coded data based on the program information. A data communication system connected to a second node to be decoded, wherein the second node has no program information for decoding data encoded by the first node; One node is
The second node transmits program information stored in the storage unit together with the data encoded by the encoding unit to the second node, and the second node decodes the data encoded by the first node. When the first node has the program information, the first node transmits the data encoded by the encoding means to the second node.

A data communication method for transmitting data encoded by a predetermined method, comprising the steps of:
The node obtains information indicating whether or not it can decode the data encoded by the predetermined method. If the node can decode the data, it transmits the encoded data as it is. The decrypted data is transmitted after being decrypted.

A data communication method for transmitting data encoded by a predetermined method, comprising the steps of:
The node obtains information indicating whether or not the node has program information for decoding the data encoded in the predetermined method, and if so, transmits the encoded data as it is. If not, it transmits the encoded data and the program information for decoding the encoded data.

[0026] A storage medium for storing a data communication program for transmitting data encoded in a predetermined format, wherein the program is transmitted from a communication destination node to a node in which the node is encoded in the predetermined format. Acquires information indicating whether data can be decoded, and if it can be decoded, transmits the encoded data as it is. If it cannot be decoded, decode the encoded data and then transmit the code. Including.

[0027] A data communication method for transmitting data encoded by a predetermined method is a storage medium for storing a program, wherein the program is transmitted from a communication destination node to the node. Acquires information indicating whether or not it has program information for decoding the data encoded in, if it has, transmits the encoded data as it is, if it does not have Includes a code for transmitting encoded data and program information for decoding the encoded data.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a network configuration when implementing the present invention. Here, in the present invention, an IEEE 1394 serial bus is used as a digital I / F for connecting each device, so the IEEE 1394 serial bus will be described in advance. << Overview of IEEE 1394 Technology >> With the advent of home digital VTRs and DVDs, it is necessary to support real-time and high-information-volume data transfer of video data and audio data. Transferring such video and audio data in real time to a personal computer (PC) or other digital equipment requires an interface capable of high-speed data transfer with the necessary transfer functions. The interface developed from such a viewpoint is IEEE1394-1995 (High Performance Ser
ial Bus) (hereinafter 1394 serial bus).

FIG. 7 shows an example of a network system configured using a 1394 serial bus. This system is equipped with devices A, B, C, D, E, F, G, H, between AB, between AC,
, DE, CF, CG, and CH are connected by a twisted pair cable of a 1394 serial bus. The devices A to H are, for example, PCs, digital VTRs, DVDs, digital cameras, hard disks, monitors, and the like.

The connection method between the devices is such that the daisy chain method and the node branch method can be mixed.
A highly flexible connection is possible.

Each device has its own unique ID and recognizes each other to form one network in a range connected by a 1394 serial bus. By simply connecting each digital device sequentially with a single 1394 serial bus cable, each device plays a role of relay and constitutes one network as a whole. It also has a function of automatically recognizing the device and the connection status when a cable is connected to the device by the Plug & Play function, which is a feature of the 1394 serial bus.

In the system shown in FIG. 7, when a device is deleted from the network or newly added, the bus is automatically reset, and the network configuration up to that point is reset. From
Rebuild a new network. With this function, the configuration of the network at that time can be constantly set and recognized.

The data transfer speed is 100/200 / 400Mbp.
s, so that devices with higher transfer rates support lower transfer rates and are compatible.

As a data transfer mode, asynchronous data such as a control signal (Asynchronous data:
Asynchronous transfer mode for transferring synchronous data (Inc data), transferring synchronous data (Isochronous data: hereinafter Iso data) such as real-time video data and audio data
There is an Isochronous transfer mode. This Async data and Iso
In each cycle (usually one cycle of 125 μS), data is transferred together with a cycle start packet (CSP) indicating the start of a cycle, followed by transfer of iso data in a cycle with priority given to transfer of iso data.

Next, FIG. 8 shows the components of the 1394 serial bus. 1394 serial bus as a whole layer
It has a structure. As shown in FIG. 8, the most hardware type is a 1394 serial bus cable, and there is a connector port to which a connector of the cable is connected.
On top of that, there are a physical layer and a link layer as hardware.

The hardware part is a substantial part of an interface chip. The physical layer performs coding and control related to connectors, and the link layer performs packet transfer and cycle time control.

The transaction layer of the firmware section manages data to be transferred (transacted) and issues commands such as Read and Write. The serial bus management is a part that manages the connection status and ID of each connected device and manages the configuration of the network.

The components up to the hardware and firmware are substantially the configuration of the 1394 serial bus.

The application of the software section
The layer differs depending on the software used, and is a part that defines how data is placed on the interface.
It is specified by a protocol such as a protocol.

The above is the configuration of the 1394 serial bus.

Next, FIG. 9 shows a diagram of the address space in the 1394 serial bus.

Each device (node) connected to the 1394 serial bus must have a 64-bit address unique to each node. And by storing this address in ROM, you can always recognize yourself and the other party's node address,
You can also communicate with the other party.

The addressing of the 1394 serial bus is based on the IE
The address is set according to the EE1212 standard. The first 10 bits are used for specifying the bus number, and the next 6 bits are used for the node ID.
Used to specify a number. The remaining 48 bits become the address width given to the device, and can be used as a unique address space. The last 28 bits store information such as identification of each device and designation of use conditions as an area of unique data.

The above is the outline of the technology of the 1394 serial bus.

Next, the technology that can be said to be a feature of the 1394 serial bus will be described in more detail. << Electrical Specifications of 1394 Serial Bus >> FIG. 10 is a sectional view of a 1394 serial bus cable.

In the 1394 serial bus, the connection cable
A power supply line is provided in addition to the two twisted pair signal lines. As a result, power can be supplied to a device having no power supply, a device whose voltage has dropped due to a failure, and the like.

The voltage of the power supply flowing in the power supply line is 8 to 40 V,
The current is specified as a maximum current of DC 1.5A. << DS-Link Encoding >> FIG. 11 is a diagram for explaining the DS-Link encoding method of the data transfer format employed in the 1394 serial bus.

In the 1394 serial bus, DS-Link (Data /
Strobe Link) coding method is adopted. This DS-L
The ink coding scheme is suitable for high-speed serial data communication, and its configuration requires two signal lines. The main data is sent to one of the twisted pairs, and the strobe signal is sent to the other twisted pair. On the receiving side, the clock can be reproduced by taking the exclusive OR of this communicated data and the strobe.

The merits of using this DS-Link encoding method are that the transfer efficiency is higher than other serial data transfer methods, and the need for a PLL circuit is eliminated.
Power consumption because the transceiver circuit of each device can be put into a sleep state because there is no need to send information indicating that the device is in an idle state when there is no data to be transferred. Can be reduced. << Bus reset sequence >> In the 1394 serial bus,
Each connected device (node) is given a node ID and recognized as a network configuration.

When there is a change in the network configuration, for example, a change occurs due to an increase or decrease in the number of nodes due to insertion / removal of a node or power ON / OFF, etc. Each of the detected nodes transmits a bus reset signal on the bus to enter a mode for recognizing a new network configuration. The method of detecting the change at this time is performed by detecting a change in the bias voltage on the 1394 port board.

When a bus reset signal is transmitted from a certain node, the physical layer of each node transmits the bus reset signal to the link layer at the same time as receiving the bus reset signal, and transmits the bus reset signal to another node. . After all the nodes finally detect the bus reset signal, the bus reset is activated.

The bus reset is also started by a cable detection as described above, a start by hardware detection due to a network abnormality or the like, and also by directly issuing a command to a physical layer by a host control from a protocol or the like.

When the bus reset is activated, the data transfer is temporarily suspended, the data transfer during this time is waited, and after the end, the data transfer is resumed under a new network configuration.

The above is the bus reset sequence. << Node ID Determination Sequence >> After the bus reset, each node starts an operation of giving an ID to each node in order to construct a new network configuration. At this time, a general sequence from the bus reset to the determination of the node ID is shown.
This will be described with reference to flowcharts 19, 20, and 21.

The flowchart of FIG. 19 shows a series of bus operations from the occurrence of a bus reset until the node ID is determined and data transfer can be performed.

First, as step S101, the occurrence of a bus reset in the network is constantly monitored. If a bus reset occurs due to power ON / OFF of the node, the process proceeds to step S102.

In step S102, from the reset state of the network, a parent-child relationship is declared between the directly connected nodes in order to know the connection status of the new network. When the parent-child relationship is determined between all the nodes as step S103, step S104
One route is decided as. Until the parent-child relationship is determined between all nodes, the parent-child relationship is declared in step S102, and the route is not determined.

When the route is determined in step S104,
Next, in step S105, a node ID setting operation for giving an ID to each node is performed. In a given node order,
The node ID is set, and the setting operation is repeatedly performed until the IDs are given to all the nodes. When the IDs are finally set to all the nodes in step S106, the new network configuration is recognized by all the nodes. Thus, as a step S107, data transfer between nodes can be performed, and data transfer is started.

When the state of step S107 is reached, a mode for monitoring the occurrence of a bus reset is again entered. If a bus reset occurs, steps S101 to S1 are performed.
The setting work up to 06 is repeated.

The above is the description of the flowchart of FIG. 19. The flowchart from FIG. 19 shows the part from the bus reset to the route determination and the procedure from the route determination to the end of the ID setting in a more detailed flowchart. Are shown in FIGS. 20 and 21, respectively.

First, the flowchart of FIG. 20 will be described.

When a bus reset occurs in step S201, the network configuration is reset once. The occurrence of a bus reset is constantly monitored in step S201. Next, as step S202, as a first step of re-recognizing the reset network connection status, a flag indicating a leaf (node) is set for each device. Further, in step S203, each device checks how many ports of its own are connected to other nodes. In accordance with the result of the number of ports in step S204, the number of undefined (undetermined parent-child) ports is checked in order to start the declaration of the parent-child relationship. Immediately after the bus reset, the number of ports is equal to the number of undefined ports, but as the parent-child relationship is determined,
The number of undefined ports detected in step S204 changes.

First, immediately after the bus reset, only the leaf can declare a parent-child relationship. The fact that the port is a leaf can be known by checking the number of ports in step S203. At step S205, the leaf declares "I am a child and the other is a parent" to the node connected thereto, and ends the operation.

The node which has a plurality of ports in step S203 and is recognized as a branch is immediately after the bus reset, since the number of undefined ports is greater than 1 in step S204, the process proceeds to step S206, and a flag of branch is first set. In step S207, the process waits for reception of “parent” in the parent-child relationship declaration from the leaf.

The leaf declares a parent-child relationship, and the branch that has received the declaration in step S207 appropriately checks the number of undefined ports in step S204. It becomes possible to declare "I am a child" in step S205 to the connected node. After the second time, even if the number of undefined ports is confirmed in step S204, for a branch having two or more ports, the process waits again in step S207 to accept a "parent" from a leaf or another branch.

Finally, if any one of the branches or exceptionally leaves (because it did not operate quickly enough to allow child declaration) becomes zero as a result of the number of undefined ports in step S204, The only node for which the declaration of the parent-child relationship of the entire network has been completed and the number of undefined ports has become zero (all are determined as parent ports) is flagged as a root as step S208,
In step S209, the route is recognized.

In this manner, the process from the bus reset shown in FIG. 20 to the declaration of the parent-child relationship between all the nodes in the network is completed.

Next, the flowchart of FIG. 21 will be described.

First, since the flag information of each node such as leaf, branch, and root is set in the sequence up to FIG. 20, the classification is performed in step S301 based on this.

As a task of assigning an ID to each node, the ID can be first set from the leaf. The IDs are set in ascending order of leaf → branch → route (node number = 0).

In step S302, the number N (N is a natural number) of leaves existing in the network is set. Thereafter, in step S303, each leaf requests the root to give an ID. If there are a plurality of such requests, the route performs arbitration (operation of arbitrating one) in step S304, and step S305.
The ID number is given to one of the winning nodes, and a failure result is notified to the losing node. I as step S306
The leaf for which acquisition of D has failed fails issues an ID request again, and repeats the same operation. At step S307, the ID information of the node is broadcast and transferred to all nodes from the leaf whose ID has been acquired. When the broadcast of the one node ID information ends, the number of remaining leaves is reduced by one in step S308. Here, as step S309, when the number of remaining leaves is one or more, the operation from the ID request of step S303 is repeatedly performed.
Eventually, when all the leaves broadcast the ID information, step S309 becomes N = 0, and the process proceeds to the branch ID setting.

The setting of the branch ID is performed in the same manner as in the leaf setting.

First, as step S310, the number M (M is a natural number) of branches existing in the network is set. Thereafter, in step S311, each branch requests the root to give an ID. On the other hand, the root performs arbitration in step S312, and gives the branch in order from the winning branch to the next youngest number given to the leaf. In step S313, the root notifies the branch that issued the request of ID information or a failure result. In step S314, the branch whose ID acquisition has failed fails issues an ID request again, and repeats the same operation. In step S315, the ID information of the node is transferred to all nodes by broadcasting from the branch from which the ID has been obtained. When the broadcasting of the one node ID information ends, the number of remaining branches is reduced by one in step S316. Here, as step S317, when the number of the remaining branches is one or more, the operation from the ID request in step S311 is repeated, and the operation is repeated until all the branches finally broadcast the ID information.
When all the branches have acquired the node ID, M = 0 in step S317, and the branch ID acquisition mode ends.

At this point, since only the root node has not acquired the ID information at the end, step S
The lowest number not given as 318
A D number is set, and the route ID information is broadcast in step S319.

As described above, the procedure from the determination of the parent-child relationship to the setting of the IDs of all the nodes is completed as shown in FIG.

Next, the operation in the actual network shown in FIG. 12 will be described as an example with reference to FIG.

As shown in FIG. 12, a node A and a node C are directly connected below the (root) node B, and a node D is directly connected below the node C.
Further, below the node D, there is a hierarchical structure in which the nodes E and F are directly connected. The procedure for determining the hierarchical structure, the root node, and the node ID will be described below.

After the bus reset, a parent-child relationship is declared between the directly connected ports of each node in order to recognize the connection status of each node. The parent and child can be said to be such that the parent is higher in the hierarchical structure and the child is lower.

In FIG. 12, it is the node A that first declared the parent-child relationship after the bus reset. Basically, a node that has a connection to only one port of a node (called a leaf) can declare a parent-child relationship. This allows the user to first know that there is only one port connection, thereby recognizing that it is at the edge of the network and determining the parent-child relationship from the node that operates earlier in that. Thus, the port on the side that has declared the parent-child relationship (node A between AB) is set as a child, and the port on the other side (node B) is set as a parent.
Thus, a child-parent is determined between the nodes A and B, a child-parent is determined between the nodes ED, and a child-parent is determined between the nodes FD.

Further, one level up, this time, among nodes having a plurality of connection ports (referred to as branches), the parent-child relationship declaration is made further higher in order from the node which received the parent-child relationship declaration from another node. To go. In FIG. 12, first, after the parent-child relationship between the node D and the node D-F is determined, a parent-child relationship is declared for the node C. As a result, the node D is determined as the child-parent between the nodes D and C. ing.

The node C, which has received the declaration of the parent-child relationship from the node D, has declared the parent-child relationship to the node B connected to another port. As a result, a child-parent is determined between the nodes C and B.

In this way, a hierarchical structure as shown in FIG. 12 is formed, and the node B which has become the parent in all finally connected ports is determined as the root node. There is only one route in one network configuration.

In FIG. 12, node B is determined to be the root node. This is because node B, which has received a parent-child relationship declaration from node A, makes a parent-child relationship declaration for other nodes at an early timing. If so, the root node may have moved to another node. That is, any node may become a root node depending on the transmission timing, and the root node is not always constant even in the same network configuration.

Once the root node has been determined,
Enter the ID determination mode. Here, all nodes notify their determined node IDs to all other nodes (broadcast function).

The self ID information includes its own node number, information on the connected position, the number of ports it has, the number of ports it has connected, information on the parent-child relationship of each port, and the like.

The procedure for assigning node ID numbers is as follows:
First, it can be started from a node (leaf) that has connection to only one port, and node number =
0, 1, 2,...

The node having the node ID broadcasts information including the node number to each node.
As a result, it is recognized that the ID number is “assigned”.

When all the leaves have acquired their own node IDs, the next step is to move to the branch and follow the leaf node ID
A number is assigned to each node. Like the leaf, the node IDs are sequentially assigned from the branch to which the node ID number is assigned.
Broadcast information, and finally the root node
Broadcast ID information. That is, the root always has the largest node ID number.

As described above, the nodes of the entire hierarchical structure
The ID assignment is completed, the network configuration is reconstructed, and the bus initialization is completed. << Arbitration >> In the 1394 serial bus, arbitration (arbitration) of the right to use the bus is always performed prior to data transfer. Since the 1394 serial bus is a logical bus-type network in which each device connected individually relays the transferred signal and transmits the same signal to all devices in the network, packet collision occurs. Arbitration is necessary to prevent This allows only one node to transfer at a given time.

As a diagram for explaining arbitration, FIG. 13 (a) shows a bus use request diagram, and FIG. 13 (b) shows a bus use permission diagram.

When the arbitration starts, one or more nodes issue a bus use request to the parent node. Node C and node F in Fig. 13 (a)
Is the node issuing the request for the right to use the bus. The parent node (node A in FIG. 13) that has received the request further issues (relays) a bus use request toward the parent node. This request is finally delivered to the arbitration route.

The root node that has received the bus use request determines which node uses the bus. This arbitration work can be performed only by the root node, and the node that has won the arbitration is given permission to use the bus. FIG.
In (b), use permission is given to the node C, and use of the node F is rejected. A DP (data prefix) packet is sent to the node that lost the arbitration,
Notify that they were rejected. The rejected node use request waits until the next arbitration.

As described above, the node that has won the arbitration and obtained the bus use permission can start transferring data thereafter.

Here, a series of arbitration flows will be described with reference to a flowchart shown in FIG.

In order for a node to be able to start data transfer,
The bus must be idle. In order to recognize that the data transfer that has been performed earlier is completed and that the bus is currently idle, a predetermined idle time gap length (eg, sub-action. Each node determines that its own transfer can be started by passing the gap.

At step S401, Async data, Iso
It is determined whether or not a predetermined gap length corresponding to data to be transferred, such as data, is obtained. Unless the predetermined gap length is obtained, the request for the right to use the bus required to start the transfer cannot be made, so the process waits until the predetermined gap length is obtained.

When a predetermined gap length is obtained in step S401, it is determined in step S402 whether there is data to be transferred. If so, a request for a bus use right is issued in step S403 to secure a bus for transfer. Emit to the route. At this time, the transmission of the signal indicating the request for the right to use the bus is finally delivered to the route while relaying each device in the network, as shown in FIG. If there is no data to be transferred in step S402, the process stands by.

Next, as step S404, step S4
When the route receives one or more bus use requests of 03, the route checks the number of nodes that have issued use requests in step S405. The selection value in step S405 is the number of nodes = 1
If (the node that has issued the use right request is one), the immediately subsequent bus use permission is given to that node. If the selection value in step S405 is the number of nodes> 1 (the number of nodes requesting use is plural), the route is set to step S406.
Arbitration work to determine one node to which use permission is given. This arbitration work is fair, and the same node does not always obtain permission each time, and the right is equally given.

In step S407, a selection is made of one of the plurality of nodes that have issued a use request in step S406, and one of the nodes whose route has been arbitrated and whose use has been granted, and the other nodes that have lost. Here, for one node that has been arbitrated and has obtained use permission, or a node that has obtained use permission without arbitration based on the selection value of step S405 and the number of use request nodes = 1, the route is set to that node as step S408. A permission signal is sent to it. The node that has received the permission signal starts transferring data (packets) to be transferred immediately after receiving the permission signal. In addition, as a step S409, a node that has lost the arbitration in step S406 and is not permitted to use the bus receives a DP (data pre
fix) A packet is sent, and the node receiving the packet returns to step S401 and waits until a predetermined gap length is obtained in order to issue a bus use request for performing the transfer again. The above is a flowchart describing the flow of arbitration. 23 is an illustration of FIG. << Asynchronous transfer >> The asynchronous transfer is an asynchronous transfer. FIG. 14 shows a temporal transition state in the asynchronous transfer. The first sub-action gap in FIG. 14 indicates the idle state of the bus. When the idle time reaches a certain value, the node desiring transfer determines that the bus can be used and executes arbitration for acquiring the bus.

When the bus use permission is obtained by arbitration, the data transfer is executed in the form of a packet.
After the data transfer, the receiving node acknowledges the ack (reception confirmation return code) of the reception result for the transferred data.
After a short gap of ap, the transfer is completed by returning and responding or sending a response packet. The ack is composed of 4 bits of information and 4 bits of a checksum, and includes information such as success, busy status, and pending status, and is immediately returned to the source node.

Next, FIG. 15 shows an example of a packet format for asynchronous transfer.

The packet has a header part in addition to the data part and the data CRC for error correction, and the header part has the destination node ID and the source node I as shown in FIG.
D, the transfer data length, various codes, etc. are written and the transfer is performed.

Asynchronous transfer is one-to-one communication from a self-node to a partner node. The packet transferred from the transfer source node is distributed to each node in the network, but the address other than its own address is ignored, so that only one destination node reads the packet.

The above is the description of the asynchronous transfer. << Isochronous (Synchronous) Transfer >> Isochronous transfer is synchronous transfer. This isochronous transfer, which can be said to be the biggest feature of the 1394 serial bus, is especially for multimedia data such as VIDEO video data and audio data.
This is a transfer mode suitable for transferring data that requires real-time transfer.

Also, if the asynchronous transfer (asynchronous) is 1
In contrast to one-to-one transfer, this isochronous transfer is uniformly transferred from one transfer source node to all other nodes by the broadcast function.

FIG. 16 is a diagram showing a temporal transition state in the isochronous transfer. Isochronous transfer
It is executed at regular intervals on the bus. This time interval is called an isochronous cycle. The isochronous cycle time is 125 μS. The start time of each cycle,
The cycle start packet plays a role of adjusting the time of each node. The node that transmits the cycle start packet is a node called a cycle master. After a transfer in the previous cycle is completed, a predetermined idle period (subaction gap) is passed, and then the start of this cycle is announced. Send a cycle start packet. The time interval at which this cycle start packet is transmitted is 125 μS.

As shown in FIG. 16 as channel A, channel B and channel C, a plurality of types of packets can be distinguished and transferred by being given a channel ID in one cycle. This allows real-time transfer between a plurality of nodes at the same time, and the receiving node fetches only the data of the channel ID desired by itself. This channel ID does not represent the address of the transmission destination, but merely gives a logical number for the data. Therefore, the transmission of a certain packet is transmitted in a broadcast manner from one source node to all other nodes.

Prior to the packet transmission in the isochronous transfer, arbitration is performed as in the asynchronous transfer. However, since it is not one-to-one communication as in the asynchronous transfer, there is no ack (reception confirmation reply code) in the isochronous transfer.

The iso gap (isochronous gap) shown in FIG. 16 represents an idle period necessary for recognizing that the bus is empty before performing the isochronous transfer. After the predetermined idle period has elapsed, a node that wishes to perform isochronous transfer determines that the bus is free, and can perform arbitration before transfer. Next, FIG. 17 shows an example of the packet format of the isochronous transfer, which will be described.

Each packet divided into channels has a header portion in addition to a data portion and data CRC for error correction, and the header portion has a transfer data length and a channel length as shown in FIG. NO, other various codes, a header CRC for error correction, and the like are written and transferred.

The above is the description of the isochronous transfer. << Bus Cycle >> In actual transfer on the 1394 serial bus, isochronous transfer and asynchronous transfer can be mixed. FIG. 18 shows a temporal transition of the transfer state on the bus in which the isochronous transfer and the asynchronous transfer are mixed at that time. The isochronous transfer is executed prior to the asynchronous transfer. The reason is that after the cycle start packet, the isochronous transfer can be started with a gap length (isochronous gap) shorter than the gap length (subaction gap) of the idle period required to start the asynchronous transfer. . Therefore, the isochronous transfer is executed with priority over the asynchronous transfer.

In the general bus cycle shown in FIG. 18, at the start of cycle #m, a cycle start packet is transferred from the cycle master to each node. As a result, each node adjusts the time, and after waiting for a predetermined idle period (isochronous gap), the node that should perform isochronous transfer performs arbitration and starts packet transfer. In FIG. 18, the channel e, the channel s, and the channel k are sequentially isochronously transferred.

After the operations from the arbitration to the packet transfer are repeatedly performed for the given channel, when all the isochronous transfers in the cycle #m have been completed, the asynchronous transfer can be performed.

When the idle time reaches the subaction gap in which asynchronous transfer is possible, the node that wishes to perform asynchronous transfer determines that it can start executing arbitration.

However, during the period in which the asynchronous transfer can be performed, a sub-action gap for starting the asynchronous transfer is obtained after the completion of the isochronous transfer until a time (cycle synch) at which the next cycle start packet is to be transferred. Only when they are given.

In cycle #m in FIG. 18, two packets (packet 1 and packet 2) of isochronous transfer for three channels and then asynchronous transfer (including ack) are transferred. After the asynchronous packet 2, it is time to start the cycle m + 1 (cycle synch), and the transfer in cycle #m ends here.

However, the time (cy) to transmit the next cycle start packet during the asynchronous or synchronous transfer operation
If cle synch is reached, the cycle start packet of the next cycle is transmitted after waiting for an idle period after the transfer is completed without forcibly interrupting the transfer. That is, when one cycle lasts for 125 μS or more, it is assumed that the next cycle is shorter than the reference 125 μS. As described above, the isochronous cycle can be exceeded or shortened on the basis of 125 μS.

However, the isochronous transfer is always performed if necessary every cycle in order to maintain the real-time transfer, and the asynchronous transfer may be transferred to the next and subsequent cycles due to the shortened cycle time.

The cycle information including such delay information is
Controlled by the master.

The above is the description of the IEEE1394 serial bus. <Direct Print System Using IEEE1394 Serial Bus> A system in which each device is connected by a 1394 serial bus cable as shown in FIG. 1 will now be described. The bus configuration in FIG. 1 includes a recording / reproducing device 101, a printer device 102, and a personal computer (PC) 103, which are connected by a 1394 serial bus drawn by solid lines, as nodes. Data can be transferred based on the specifications. Here, the recording / reproducing device 10
Reference numeral 1 denotes a digital camera, a camera-integrated digital VTR, or the like that records and reproduces a moving image or a still image. Further, direct printing is possible by directly transferring the video data output from the recording / reproducing apparatus 101 to the printer 102. Also,
The connection method of the 1394 serial bus is not limited to the connection as shown in FIG. 1, but it is also possible to configure the bus by connecting any devices. In addition to the devices shown in FIG. A configuration in which a data communication device is connected may be employed. In addition,
The network of FIG. 1 is an example of a device group,
The connected device may be any device that can form a network with an external storage device such as a hard disk or a 1394 serial bus such as CDR or DVD.

The operation of the present embodiment will be described with reference to FIG. 2 with the bus configuration as shown in FIG.

In the recording / reproducing apparatus 101, reference numeral 4 denotes an imaging system,
Reference numeral 5 denotes an A / D converter, 6 denotes a video signal processing circuit, 7 denotes a compression / expansion circuit which compresses during recording and decompresses during reproduction by a predetermined algorithm, and 8 includes a magnetic tape, a solid-state memory, and its recording / reproducing head. Recording / reproducing system, 9 is a system controller, 10 is an operation unit for inputting an instruction, and 11 is a D / D
A converter, 12 is an EVF as a display unit, 13 is a frame memory for storing video data to be transferred uncompressed, 14 is a memory control unit for controlling reading of the memory 13, etc., 15 is compressed video data to be transferred A frame memory for storing, 16 a memory control unit for controlling reading of the memory 15 and the like, 17 a data selector, 18 an I / O of the 1394 serial bus
Section F.

In the printer 102, 19 is a 1394 I / F section of the printer, 20 is a data selector, 21 is a decoding circuit for decoding video data compressed by a predetermined algorithm, and 22 is a print image. An image processing circuit, 23 is a memory for forming a print image, 24 is a printer head, 25 is a driver for performing a printer head or paper feed, 26 is a printer controller which is a control unit of the printer, and 27 is a printer operation unit. .

Further, in the PC 103, 61 is a 1394 I / F unit mounted on the PC, 62 is a PCI bus, 63 is an MPU,
64 is a decoding circuit for decoding video data compressed by a predetermined algorithm, 65 is a display with a built-in D / A converter, 66 is an HDD, 67 is a memory, and 68 is an operation unit such as a keyboard and a mouse. It is.

Next, the operation of the block diagram 2 will be described step by step.

<Operation of Recording / Reproducing Apparatus> First, at the time of recording by the recording / reproducing apparatus 101, an analog video signal photographed by the image pickup system 4 is digitized by the A / D converter 5, and then is processed by the video signal processing circuit 6. Video processing is performed. One of the outputs of the video signal processing circuit 6 is converted back to an analog signal by the D / A converter 11 as a video being captured, and is displayed on the EVF 12.
Other outputs are compressed (encoded) by a compression circuit 7 according to a predetermined algorithm, and are recorded on a recording medium by a recording / reproducing system 8. Here, the predetermined compression processing is a compression method based on DCT (Discrete Cosine Transform) and VLC (Variable Length Coding) as a band compression method in a digital VTR for home use, which is typical in a digital camera. Others include the MPEG system.

At the time of reproduction, the recording / reproducing system 8 reproduces a desired video from the recording medium. At this time, selection of a desired video is selected based on an instruction input input from the operation unit 10, and is controlled and reproduced by the system controller 9. Of the video data reproduced from the recording medium, data transferred in a compressed state is output to the frame memory 15. When the reproduction data is expanded (decoded) for transfer as uncompressed data, it is expanded by the expansion circuit 7 and output to the memory 13. When displaying the reproduced video data on the EVF12,
After being expanded by the expansion circuit 7 and returned to the analog signal by the D / A converter 11, it is output to the EVF 12 and displayed.

Frame memory 13 and frame memory
In 15, writing / reading is controlled by memory controllers 14 and 16 controlled by a system controller, and the read video data is output to a data selector 17. At this time, the outputs of the frame memories 13 and 15 are controlled so that one of them is output to the data selector 17 at the same time.

The system controller 9 includes a recording / reproducing device 10
1 controls the operation of each unit in the printer 102.
Command data for an externally connected device such as the
Asynchronous commands transferred to external devices via serial bus
c You can also transfer. Also, the printer 102 and the PC 103
The various command data transferred from the storage device 101 are input from the data selector 17 to the system controller 9 and can be used for controlling each unit of the recording / reproducing apparatus 101. Among them, command data indicating the presence or absence of a decoder or the type of the decoder, which is transferred from the printer 102 or the PC 103 by Async, is input to the system controller 9 as a request command. Thereafter, based on the command data, when transferring the video data from the recording / reproducing apparatus 101, it is determined whether to transfer the compressed or uncompressed video data, and the command is sent to the memory control units 14 and 16 accordingly. Then, control is performed so that one suitable video data is read out from the frame memory 13 or 15 and transferred.

The determination as to which of the compressed and uncompressed video data is to be transferred is made based on the information of the decoder included in each device, which is transferred from the printer 102 or the PC 103 as a command. When it is determined from the information that the video data compression method in the recording / reproducing apparatus 101 can be decoded, the data read from the memory 15 is output to transfer the compressed video data, and it is determined that the data cannot be decoded. If it is, control is performed to output data read from the memory 13 to transfer uncompressed video data.

The video data and command data input to the data selector 17 are transferred on the cable by the 1394 I / F 18 based on the specification of the 1394 serial bus. If so, the PC 103 receives it. Command data is also Async transferred to the target node as appropriate. Regarding the data transfer method, mainly data such as moving images, still images, and audio are transferred as Iso data by the isochronous transfer method, and command data is transferred as Async data by the asynchronous transfer method. However, among the data transferred by the normal Iso data, if it is more convenient to transfer the data as Async data depending on the transfer situation or the like, the data may be transmitted by asynchronous transfer.

<Operation of Printer> On the other hand, in the printer 102, the data input to the 1394 I / F unit 19 is classified by the data selector 20 according to the type of each data, and the data to be printed such as video data is compressed. If the data has been decompressed by the decoding circuit 21, the image processing circuit 22
Is output to As described above, the recording / reproducing apparatus 101 performs data transfer by selecting compression or non-compression so that optimum transfer can be performed based on information such as the presence / absence or type of the decoder which is transmitted in advance. Therefore, even if the transfer data is compressed, the received data can be expanded (decoded) by the expansion method of a predetermined algorithm in the decoding circuit 21 provided in the printer. If the transferred video data is uncompressed, the decoding circuit 21 does not exist in the printer 102 or the decoding circuit 21 that cannot support the compression method of the recording / reproducing apparatus 101 is connected to the printer 102.
Is provided. In this case, the received data is directly input to the print image processing circuit 22 through the decoding circuit 21. Also, when print data or the like that is not video data is input and the data does not need to be expanded, the decoding circuit 21 is skipped.

The print data input to the image processing circuit 22 is subjected to image processing suitable for printing here.
The image is developed as a print image in the memory 23 whose storage and reading are controlled by the printer controller 26. This print image is sent to the printer head 24 and printed. Driver for printer head drive and paper feed drive
The operation control of the driver 25 and the printer head 24 and the control of other parts are performed by the printer controller 23.
Done by

The printer operation unit 27 is used to feed paper, reset,
This is for inputting an instruction such as an ink check or a standby / start / stop of the printer operation, and the printer controller 26 controls each unit in response to the input of the instruction.

Next, when the data input to the 1394 I / F unit 19 is command data for the printer 102, the data is transmitted as a control command from the data selector 20 to the printer controller 26, and the printer controller 26 responds to the information. Control of each part of the printer 102 is performed.

The printer controller 26 is a printer
102 to output information such as the type of decoder included in the decoding circuit 21 or the presence / absence of the decoding circuit 21;
Async transfer can be performed to 101 as command data.

Here, the JPEG system can be considered as an example of the decoder provided in the printer for the decoding circuit 21. Since JPEG decoding is possible by software, the decoding circuit 21 stores the JPEG
A configuration may be used in which the decryption program file is held, or the decryption program is transferred from another node, and the like, and the decryption processing is performed by software. If the image data compressed by the JPEG method is transferred from the recording / reproducing device to the printer, and the data is decoded in the printer, the transfer efficiency is better than converting the data to uncompressed data before transferring the data. By using the decoding process in (1), providing a decoder in the printer itself does not hinder the cost and is convenient. Further, the decoding circuit 21 may be configured to provide a JPEG decoding circuit (board) as hardware decoding.

As described above, when video data is transferred from the recording / reproducing apparatus 101 to the printer 102 for printing, it is so-called direct printing, and printing can be performed without using a PC.

<Operation of Personal Computer> Next,
The processing in the PC 103 will be described.

From the recording / reproducing device 101, the 1394 I / F of the PC
The video data transferred to the unit 61
The data is transferred to each unit using the bus 62 as a bus for mutual data transmission. Also, various command data and the like in the PC 103 are transferred to each unit using the PCI bus.

The PC 103 uses the memory 67 in accordance with an instruction input from the operation unit 68 and an OS (operating system) or application software, and
The processing is performed by U63. When recording the transferred video data, it is recorded on the hard disk 66.

As with the printer, the video data to be transferred is compressed or uncompressed so that the recording / reproducing apparatus 101 can perform optimal transfer based on information such as the presence / absence of a decoder or the type of decoder previously received. This is the transferred data. Therefore, even if the received video data is compressed data, the decoding circuit 64
The data can be decompressed by the decompression method of a predetermined algorithm possessed by.

When the video data is displayed on the display 65, if it is compressed video data, a decoding circuit is used.
If it is uncompressed video data after being decoded at 64, it is directly input to the display 65, and after D / A conversion, it is displayed as a video.

The various decoding circuits 64 provided in the PC 103 are, for example, those in which a decoder of the MPEG system or the like is inserted into a slot as a board, those which are built into the main body by hardware, or those which are MPEG system or JPE.
The G system and other soft decoders are owned by a ROM or the like, and a command can be transferred to the recording / reproducing device 101 as information on the type and presence / absence of these decoders.

[0146] The transferred video data is taken into the PC 103 and recorded, edited, transferred from the PC to other devices, and the like.

The system according to the present embodiment is configured as shown in FIG.
Alternatively, before transferring the video data to the PC 103, the information is output from the printer 102 or the PC 103 of the transfer destination to the Async transfer including the information of the decoder in the command. If data cannot be transferred and decoded, it can be selected to transfer uncompressed video data. <Video Data Transfer Procedure> Next, FIG. 4 is a flowchart showing the operation of the recording / reproducing apparatus 101 at the time of video data transfer.

The video data in the recording / reproducing apparatus 101 is
In the mode in which data is transferred to another device connected via the serial bus 394, first, as step S1, data transfer to the transfer destination device is set based on the designation by the user. As a result, as step S2, the recording / reproducing apparatus 101 includes predetermined information indicating that transfer is to be performed and information for prompting transfer of information such as the presence / absence and type of a decoder provided in the transfer destination device. Async transfer the command to the transfer destination device using the 1394 bus. In response to the command in step S2, predetermined transfer confirmation command data including decoder information is Async-transferred from the transfer destination device to the recording / reproducing device 101, and the recording / reproducing device 101 receives the command.

At step S3, the system controller 9 of the recording / reproducing apparatus 101 determines whether or not the decoder information has been received. If the decoder information has been received and the presence and the type of the decoder can be determined, the process proceeds to step S4. When the received command does not include the decoder information because the device cannot transmit the command to the decoder information, or when the command includes information indicating that the decoder does not exist, or the transfer destination device. Command is not returned or a transfer error on the bus or
If the command Async transfer is not received even after the predetermined period has elapsed due to a delay of the Async transfer or the like, step S6
Move on to

Here, of the command data transferred from the transfer destination device to the recording / reproducing apparatus 101 as the transfer source, the decoder information is compressed when the video data recorded after compression is transferred. This data is used as a basis for determining whether to transfer as it is or to return to uncompressed before transferring. That is, this data also has a role as request data as to whether the transfer destination device desires the transfer of the compressed data or the transfer of the uncompressed data. Therefore, the recording / reproducing device 10 of the transfer source is
If the transfer destination device, for example, the PC 103 knows in advance the information on the compression method used by the PC 1, the response to the command sent from the recording / reproducing device in step S 2 is simply a response including the decoder information in the PC 103. Instead, the transfer of video data can be used as a request command for specifying whether to transfer compressed data or uncompressed data.

Next, in step S4, the type of the decoder determined from the received decoder information is
If the decoder can support the compression method of the predetermined algorithm of the video data used in the compression / expansion circuit 7, the decoder can be decoded in the transfer destination device. In order to transfer the compressed video data to the 1394 bus by ISO, control is performed so that the output from the memory 15 is transferred when the video data is transferred. When the type of the decoder determined in step S4 is incompatible with the compression method of the recording / reproducing apparatus 101, and when the decoder information is not received in step S3, that is, there is no decoder in the transfer destination device. If it is determined not to do so, step S6
Setting without a decoder, ie, the recording / reproducing device 101
In order to perform ISO transfer of uncompressed video data on the 1394 bus after decompressing the video data to be ISO transferred within
Control is performed so that the output from the memory 13 is transferred when the transfer of the video data is executed.

After setting the output format at the time of the video data transfer according to the transfer destination device in this way, the user then transfers the video data to be transferred to a recording medium for printing or taking in a PC at step S7. Select from among the images recorded in. The recording / reproducing device 101 performs an operation of reading the selected video. After performing the image selection operation, the user issues a transfer instruction for a desired image in step S8.

Next, based on the settings in steps S5 and S6, it is determined in step S9 whether or not there is a decoder compatible with the transfer destination device. If so, in step S10 the compressed video data reproduced from the recording medium is determined. In order to perform the ISO transfer, the system controller 9 and the memory controller 16 control to output and transfer the video data read from the memory 15 in response to the transfer command in step S8. If not, in step S11, the system controller outputs and transfers the video data read from the memory 13 in response to the transfer command in step S8 in order to perform the ISO transfer of the uncompressed video data expanded by the expansion circuit 7. 9 and memory control 14
Controls. Basically, video data is transferred using an isochronous transfer method using a 1394 serial bus, but may be transferred using an asynchronous transfer.

When the transfer of the desired video data is completed in step S12, it is determined in step S13 whether transfer of other video data is desired or selected by the user. If another video is selected, step S7 is performed.
Returning to step S12, the process is repeated from the selection of a video. If another video is not selected, the process proceeds to step S14. In step S14, it is determined whether or not to change the transfer destination device to continue the video data transfer mode. If the transfer destination is changed to another device to transfer the video data, the process is repeated from the transfer destination designation in step S1. If it is not necessary to change the transfer destination and continue the mode, the flow is terminated here. The flow always returns to step S1 with the execution of the instructed video data transfer mode, and the flow is repeated.

As described above, the recording / reproducing apparatus of the present embodiment obtains information indicating the decoding procedure of the transmission destination from the transmission destination of the video data, and obtains the information from the obtained information. If the encoding is performed in a procedure corresponding to the decoding order of the transmission destination, the encoded video data is transmitted, otherwise the encoded data is decoded,
Send it. Thus, data transmission / reception can be performed reliably regardless of what encoding / decoding procedure the device connected by communication has. Furthermore, if the communicating devices have the same encoding / decoding procedure, the encoded data will be transmitted / received, so that the communication can be performed quickly and the capacity of the memory required for transmission / reception is also reduced. It can be reduced compared to the case where data communication is performed with the data thus obtained. [Second Embodiment] Next, a second embodiment will be described. <System Configuration> In the second embodiment, the recording / reproducing apparatus 201 and the printer 202 as shown in FIG.
It is implemented in a bus configuration connected with a 1394 serial bus cable. At this time, direct printing, in which the video data from the recording / reproducing device 201 is printed by the printer 202, is realized.

A block diagram at this time is shown in FIG. The configuration of the block diagram 6 is basically a configuration in which a PC is removed from the configuration of the first embodiment shown in the block diagram 2 and a 1394 I / F of a recording / reproducing device and a printer is connected in a peer-to-peer manner. It is. The difference from the block diagram 2 is that MPEG and JPE performed by the compression circuit 7 of the recording / reproducing apparatus 201 are different.
Decoding program information mainly formed by a soft decoding program for expanding data compressed by a video data compression method such as the G or DV method is stored in a ROM 74.
The program information is read from the ROM 74 under the control of the system controller 9 and the read control unit 73 as needed, and the data selectors 17 to 13 are stored.
The point is that the data is transferred to another node via the 94 I / F unit 18.

The transfer form of the decode program information is mainly the asynchronous transfer method, and in some cases, the ISO transfer. The transfer is performed in the gap before the transfer of the video data or in parallel with the transfer of the video data packet. Transfer. In FIG. 6, a memory 1 for transferring uncompressed data in the recording / reproducing device 201 is shown.
3 and its memory control unit 14 are not provided.

On the other hand, in order to decode the video data, the printer 202 receives the above-mentioned decode program information from the recording / reproducing apparatus 201 before or in parallel with the video data, and decodes it in whole or in part. It is stored in the rewritable memory 71. The received compressed video data is decoded by the decoding processing circuit 72 using the decoding program information stored in the memory 72.

The memory 71 is capable of rewriting and storing a decoding program in accordance with a connected device that transfers compressed data, and has a configuration that can be used together with the decoding processing circuit 72 to function as a plurality of types of decoders. memory
The configuration may be such that the decoder 71 cannot operate at all unless a decoding program is obtained from another device, but only a predetermined decoding program may be provided in a part of the memory 71 in advance.

Note that compatibility between the transmitted and received decode program information between the recording / reproducing apparatus 201 and the printer 202 must be ensured. For this purpose, the decoding processing circuit 72 may be standardized in advance, and the decoding program information described in accordance with the standard may be stored in the ROM 74. Alternatively, only the way of describing the decoding program information may be standardized, and the decoding processing circuit 72 may be configured to interpret and execute the standardized program information.

The other circuit elements and their operations in the block diagram 6 are the same as those described in the first embodiment, and a description thereof will be omitted.

When transferring the compressed print video data from the recording / reproducing apparatus 201 to the printer 202, first, prior to the transfer of the video data, decode the video data in accordance with the compression method of the video data used in the recording / reproducing apparatus 201. The program is read from the ROM 74 and Async-transferred to the printer 202. The printer 202 stores the received decoding program in the memory 71 and uses it for decoding the compressed video data to be transferred. In the recording / reproducing apparatus 201, one compression / expansion method is used for all video data to be recorded. However, a recording state in which a plurality of types of compression methods are mixed for any video data amount or time may be used.

With this configuration, the compressed video data can be transferred without having the decoder information in the printer, so that the transfer efficiency is higher than the transfer of the uncompressed video data.

Next, the operation of the second embodiment will be described with reference to a flowchart of FIG. 24, which will be used for explanation. <Procedure of Data Transfer> First, at step S21, the user is caused to specify a transfer destination device. In the present embodiment, the printer is designated. The transfer setting is performed based on the instruction.

Next, the user selects video data to be printed from the videos recorded on the recording medium.
In step S22, the recording / reproducing device 201 performs a read operation of the selected video. When the image selection operation is performed, the user is instructed to transfer a desired image in step S23.

In step S24, it is determined whether it is necessary to transfer a decode program necessary for decoding the video data for which the transfer command has been issued, to the transfer destination device, here the printer 202. If it is necessary, that is, the necessary decoding processing circuit 72 for the decoding processing is provided in the printer.
If it is determined that the compressed video data can be decoded by transferring the decoding program, the necessary decoding program is read from the ROM 74 as step S25 and transferred to the printer 202.

In the printer 202, the received decode program information is stored in the memory 71.

On the other hand, if it is determined in step S24 that the transfer is unnecessary, that is, the transfer destination printer 202 has the necessary decode program information in advance, or the same decode program information has been transferred in the past. For example, when the decode information required this time is already stored in the memory 71, the transfer of the decode program information is not performed, and the transfer to the video data is started.

The information for determining whether or not the transfer of the decode program information to the printer 202 is unnecessary is transmitted from the recording / reproducing apparatus 201 to the printer 202 in step S23. Can be obtained by responding information indicating what decode program information it has.

Subsequently, in step S26, the compressed video data whose transfer has been instructed is read from the recording medium and
And transfers it to the printer 202.

When the printer 202 receives the compressed video data, it decodes the video data based on the already stored decode program information, and starts printing the video data. If the transfer of the decoding program is not completed due to the Async transfer, the video data decoding process is started after the completion of the transfer of the decoding program.

In step S27, when the transfer of the desired video data is completed, predetermined processing accompanying the transfer is performed. In step S28, it is determined whether or not the transfer of another video data has been selected, and the other video is selected. If so, the process returns to step S22 and repeats from the video selection. If another video is not selected, the flow ends. In addition, this flow is repeated from step S21 as needed in accordance with the instruction to execute the video data transfer mode.

As described above, in the system according to the present embodiment, since the decoding program information of the decompression method according to the video compression method by the recording / reproducing device is provided from the recording / reproducing device to the printer, it is transferred between the devices. Video data is always compressed data. For this reason, the data amount is reduced, and it is not necessary to perform a decompression process before transfer, and data can be transferred quickly. In addition, the data receiving side requires much less memory for storing the data than when receiving uncompressed data. [Third Embodiment] Next, a third embodiment will be described.

In the third embodiment, as in the second embodiment, the recording / reproducing apparatus 201 and the printer 202 as shown in FIG.
And a node, and peer-to-
Implement with a bus configuration with peer connection and a configuration that allows direct printing. <System Configuration> FIG. 23 is a block diagram for explaining the third embodiment. The configuration of block diagram 23
Recording / reproducing apparatus 201 of block diagram 6 used in the embodiment of FIG.
In addition, the frame memory 13 and the memory control unit 14 used in the block diagram 2 are added in order to transfer uncompressed video data.

In the third embodiment, the transfer of the decode program information from the ROM 74, the transfer of the compressed video data from the frame memory 15, and the transfer of the uncompressed video data from the frame memory 13 are transferred from the printer 202. Based on command data (decoder information) including information on the presence / absence, type, and configuration of a decoder to be used, the system controller 9 transfers only compressed video data or transfers compressed video data and decode program information. It is determined whether or not to transfer the uncompressed video data, and each unit is controlled, and data transfer is performed as needed.

More specifically, the memory 7 in the printer 202 is obtained from the decoder information in the printer 202 transferred in advance.
When there is information for decoding the compression method used in the recording / reproducing apparatus 201 in part or all of 1 and it is determined that decoding processing of the compressed video data is possible (hardware decoding means may be used). In the meantime, the system controller 9 controls the memory 15 via the memory control unit 16, reads out the compressed video data according to the user's instruction,
Start transfer.

According to the decoder information from the printer, compressed video data cannot be decoded due to lack of a decoding program or the like at present, but the memory which is a part of the decoding circuit system
By providing the decoding program information to 71, the decoding processing circuit 72 in the printer can be used, and when it is determined that decoding is possible in the printer, the ROM reading control unit 73 is controlled, and the necessary decoding program information is read from the ROM 74. Is transferred to the memory 71 via Async, and the compressed video data is read from the memory 15 via the memory control unit 16 and is controlled to be transferred.

On the other hand, when it is determined from the decoder information from the printer that the decoding circuit system including the memory 71 and the decoding means 72 in the printer does not exist or cannot be used, or the command including the decoding information has not been received. At times, it is impossible to decode the compressed video data in the printer, so that control is performed such that uncompressed video data is read from the memory 13 via the memory control unit 14 and transferred.

The components in block diagram 23 and the operation thereof are the same as those described in the first or second embodiment, and a description thereof will be omitted.

With this configuration, it is possible to transfer the compressed video data as much as possible, so that the transfer efficiency is higher than the transfer of the non-compressed video data. Even if the compressed video data cannot be transferred, the non-compressed video data can be transferred. Can be transferred, which is convenient.

Next, the operation of the third embodiment will be described with reference to a flowchart shown in FIG.

First, in step S31, when the transfer destination device is designated as a printer by the user, transfer setting is performed based on the instruction. As a result, the recording / reproducing apparatus 201 transfers to the printer 202, as step S32, the predetermined information informing that the transfer is to be performed and the information such as the presence / absence, type, and configuration of the decoder provided in the transfer destination device. Async-transfers a command containing information for prompting the user using the 1394 bus. In response to the command of step S32, predetermined transfer confirmation command data including decoder information is Async-transferred from the printer 202 to the recording / reproducing apparatus 201.

Here, the system controller 9 of the recording / reproducing apparatus 201 determines whether the reception of the decoder information has been confirmed in step S33. If the decoder information has been received, the process proceeds to step S34, and the printer 202 has a decoder function. If the decoder information is not received due to the device not being able to transmit the command or the device cannot transmit the decoder information, the command including the decode information is not returned, or a transfer error on the bus or Async
Command As even after a specified period due to transfer delay, etc.
If the INC transfer has not been received, the recording / reproducing apparatus 201 shifts to a mode for transferring only uncompressed video data, and shifts to step S40.

Next, in step S34, the decoder function of the printer is checked from the decoder information, and if it is determined that all the compression methods used in the recording / reproducing apparatus 201 can be supported, a predetermined decoding program is transferred to step S35. If it is determined that the compressed video data can be decoded, the process proceeds to step S45. The decoding means provided in the printer 202 does not support the method of transferring the decoding program, and the provided decoder cannot support the decoding. If it is impossible to decode the video data to be transferred because there is no means for decoding itself, the process proceeds to step S40, and the mode is shifted to each mode.

Here, of the command data transferred from the printer 202 to the recording / reproducing apparatus 201 which is the transfer source, decoder information is transferred as it is compressed when transferring video data recorded after compression. The data to be used to determine whether to transfer the compressed data together with the decoding program, or to transfer the compressed data together with the decoding program, and to serve as request data regarding the transfer mode from the printer 202. It will also have a role. Further, if the predetermined information is notified in advance between the nodes, when the command data for transfer confirmation for step S32 is returned, the command data is not in the form of the decoder information.
Direct transfer of compressed data related to direct video data transfer,
It can also be used as a request command meaning an uncompressed data transfer command and a decode program transfer command.

Next, the decoding means in the printer 202
When it is possible to decode the compressed video data by any compression method performed by the recording / reproducing apparatus 201, since the compressed video data can be transferred, the flow enters the flow from step S35 onward as the mode for transferring the compressed video data.

At step S35, the video data selected by the user is selected from the video data recorded on the recording medium, and the recording / reproducing apparatus 201 performs the reading operation.
After performing the image selection operation, in step S36, the user is instructed to transfer a desired image. In step S37, the video data instructed to be transferred is reproduced from the recording medium for transfer while being compressed,
And then ISO transfer to the printer. The printer performs a decoding process of the video data based on a predetermined operation procedure, and starts a printing process of the video data.

When the transfer of the desired video data is completed in step S38, a selection to transfer another video data is made in step S39. When another video is selected, the process returns to step S35 and repeats from the video selection. If no other video is selected, the process ends here.

On the other hand, if the printer 202 cannot transfer the compressed video data using the present system and decoding is impossible due to the configuration of the printer 202, the video data to be printed is always transferred by transferring the non-compressed video data. Can be transferred. As a mode for transferring the uncompressed video data at this time, the flow from step S40 is entered.

At step S40, the user selects the video data to be printed from the videos recorded on the recording medium. The recording / reproducing device 201 performs a read operation of the selected video data. After performing the image selection operation, the user issues a transfer instruction for a desired image in step S41. In step S42, the video data instructed to be transferred is decoded by the decompression circuit 7 so as to be in an uncompressed state, output from the frame memory 13, and transferred to the printer by ISO. The printer starts print processing of video data based on a predetermined operation procedure.

At step S43, when the transfer of the desired video data is completed, at step S44, a selection to transfer another video data is made. When another video is selected, the process returns to step S40 and repeats from the video selection. If no video is selected, the process ends here.

Next, by giving a predetermined decoding program to the decoder means provided in the printer 202,
When it becomes possible to decode the compressed video data to be transferred, the flow enters the flow from step S45 on as a mode for transferring the decoding program and the compressed video data.

At step S45, the user is caused to select the video data to be printed from the videos recorded on the recording medium. The recording / reproducing device 201 performs a read operation of the selected video data. After performing the image selection operation, the user is instructed to transfer a desired image in step S46.

In step S47, it is determined whether or not it is necessary to transfer a predetermined decoding program required for decoding the video data in the transfer destination printer 202 to the video data for which the transfer command has been issued. In step S48, the necessary decoding program is stored in the ROM 74.
Async (or ISO) to printer 202
Forward. The printer 202 stores the received decoding program information in the memory 71, and performs a decoding process together with the decoding processing circuit 72.

Also, in step S47, whether hardware or software decoding means is provided in advance,
Alternatively, when it is determined that the transfer of the decode program is not necessary, for example, when the same decode program has been transferred in the past and the decode information required this time has already been stored in the memory 71, the transfer of the decode program is not performed. Then, transfer to the video data.

Subsequently, in step S49, the video data for which transfer has been instructed is read from the recording medium, output from the memory 15 in a compressed state, and is ISO-transferred to the printer. The printer decodes the transferred video data using an existing or transferred decoding program based on a predetermined operation procedure, and starts printing the video data.

When the transfer of the desired video data is completed in step S50, a selection to transfer another video data is made in step S51. When another video is selected, the process returns to step S45 and repeats from the video selection. If no video is selected, the process ends here.

The flow always returns to step S31 with execution of the designated video data transfer mode, and this flow is repeated.

As described above, the system of the first embodiment and the system of the second embodiment can be combined. In this system, encoded data is transmitted and decoded to a device that receives decoded program information and decodes the encoded data according to the information, and a device that incorporates a circuit that executes a decoding procedure of various types. Unencoded data is transmitted to a device having no function. For this reason, the time required for data transmission is reduced, and the utilization efficiency of the storage area is improved.

Although the present embodiment has been described using video data compressed and recorded on a recording medium, the present invention is not limited to recorded video, but video data input from an imaging device and recording processing has been performed. It may be one using no compressed video data.

The recording / reproducing apparatus according to the embodiment mainly relates to video data of moving images and still images, and is conscious of a camera-integrated VTR and a digital camera, but is another recording or reproducing apparatus. Digital devices such as DVDs, MDs, CDs, and PCs.
The data to be handled is not limited to video data, but may be audio data or various file data.

[0202]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

An object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU) of the system or the apparatus.
Or MPU) reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instructions of the program code. ) Performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, the program code is written based on the instruction of the program code. The case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing.

[0208]

As described above, according to the present invention, when performing data transfer, the transfer source node selects coded data or uncoded data according to the decoding function of the transfer destination node. , Transfer efficiency between nodes is improved.

When the transfer destination node cannot decode the encoded data transferred from the transfer source node, the data transfer can be performed by transferring the non-encoded data regardless of the decoding function of the transfer destination node. .

Further, by transferring the program information for decoding to the transfer destination node, the transfer destination node can decode it regardless of the coding method of the transfer source node.

[0211] For this reason, the chance of performing data transfer with encoded data increases, so that the time required for data transfer can be reduced and the capacity required for storing received data can be reduced.

[0212]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a network according to a first embodiment.

FIG. 2 shows a recording and reproducing apparatus to which the first embodiment is applied;
FIG. 2 is a block diagram of a printer and a PC.

FIG. 3 is a block diagram showing a configuration when a digital camera, a PC, and a printer are connected around a PC in a conventional example.

FIG. 4 is a flowchart showing an operation flow in the recording and reproducing apparatus according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of a network according to the second and third embodiments of the present invention.

FIG. 6 is a block diagram of a recording / reproducing device and a printer device to which the second embodiment is applied.

FIG. 7 is a diagram illustrating an example of a network configuration connected using a 1394 serial bus.

FIG. 8 is a diagram illustrating components of a 1394 serial bus.

FIG. 9 is a diagram showing an address map of a 1394 serial bus.

FIG. 10 is a sectional view of a 1394 serial bus cable.

FIG. 11 is a diagram for explaining a DS-Link coding scheme.

FIG. 12 is a diagram for explaining a topology setting for determining an ID of each node on a 1394 serial bus.

FIG. 13 is a diagram for explaining arbitration on a 1394 serial bus.

FIG. 14 is a basic configuration diagram illustrating temporal state transition of asynchronous transfer.

FIG. 15 is a diagram showing an example of a format of an asynchronous transfer packet.

FIG. 16 is a basic configuration diagram showing a temporal state transition of isochronous transfer.

FIG. 17 is a diagram illustrating an example of a format of an isochronous transfer packet.

FIG. 18 is a diagram illustrating an example of a bus cycle showing a state of a packet transferred on an actual bus in a 1394 serial bus.

FIG. 19 is a flowchart showing a flow from a bus reset to a determination of a node ID.

FIG. 20 is a flowchart illustrating the flow of parent-child relationship determination in a bus reset.

FIG. 21 is a flowchart showing a flow from the determination of the parent-child relationship in the bus reset to the determination of the node ID.

FIG. 22 is a flowchart for explaining arbitration.

FIG. 23 is a block diagram of a recording / reproducing device and a printer device to which the third embodiment is applied.

FIG. 24 is a flowchart showing the operation of the second embodiment.

FIG. 25 is a flowchart showing the operation of the third embodiment.

[Brief description of reference numerals]

 Reference Signs List 4 imaging system 7 compression / expansion circuit 8 recording / reproducing system 9 system controller 13, 15 memory 18, 19, 61 1394 interface 21 decoding circuit 26 printer controller 63 MPU 64 decoding circuit 101 recording / reproducing device 102 printer device 103 PC (personal computer) )

Claims (27)

[Claims] An encoding means for encoding data in a predetermined method, a first mode for transmitting data in an encoded state, and data before encoding or data after encoding are mixed. Transmitting means for transmitting data to the communication destination node in any one of the second modes for transmitting in the communication mode described above, capable of isochronous transfer and asynchronous transfer, and the coding method by the coding means If the encoding method corresponds to the decoding means provided in the node, the first
Control means for controlling the transmitting means so as to transmit data in the second mode when the mode is not supported. 2. The data communication apparatus according to claim 1, wherein said transmitting means is means for transmitting said data by isochronous transfer. 3. The data communication device according to claim 1, wherein the data is image data. 4. The data communication according to claim 1, wherein the control unit determines, by communication using isochronous transfer, whether or not the communication destination node supports the encoding method by the encoding unit. apparatus. 5. The data communication apparatus according to claim 1, wherein said transmission means is means for performing transmission conforming to the IEEE 1394 standard. 6. The control unit determines that the communication destination node is compatible with the encoding method by the encoding unit when there is no appropriate response by the communication by the synchronous transfer. The data communication device according to claim 4, wherein 7. The data communication device according to claim 6, wherein the appropriate reply is a reply within a predetermined period. 8. The data communication apparatus according to claim 1, wherein the transmitting unit transmits the data in the second mode when the communication destination node does not include the decoding unit. 9. A receiving means for receiving, from a node at the communication destination, the presence / absence of decoding means provided in the node and, if there is a decoding means, information such as the configuration and compression method thereof,
The data communication apparatus according to claim 1, wherein the transmission in the first mode or the second mode is based on information received by the receiving unit. 10. An encoding means for encoding data by a predetermined method, a first transmission means for transmitting program information including a decoding procedure for decoding data encoded by the encoding means, and said encoding means A data communication apparatus comprising: a second transmission unit capable of transmitting data encoded by the unit and capable of performing isochronous transfer and asynchronous transfer. 11. A receiving means for receiving, from a node of a communication destination, information indicating a configuration, a compression method, and the like of a decoding means provided in the node, wherein the first transmitting means receives the information by the receiving means. The data communication device according to claim 10, wherein the program information is transmitted based on the obtained information. 12. The apparatus further comprises third transmitting means for decoding and transmitting the encoded video data, and the communication destination node comprises decoding means for decoding the data encoded by the encoding means. The encoded data is transmitted by the second transmitting means, and if the communication destination node can decode the data encoded by the encoding means when receiving the program information, the transmitting node transmits the encoded data. Means for transmitting program information and transmitting the encoded data by the second transmitting means. If the communication destination node cannot decode the data encoded by the encoding means, the third transmission The data communication device according to claim 10, wherein the data is transmitted by the means. 13. The data communication device according to claim 1, further comprising an imaging unit that captures video data. 14. A first node comprising encoding means,
What is claimed is: 1. A data communication system comprising a second node connected to a first node, wherein said first node encodes data in a predetermined manner, and said first node transmits data in an encoded state. Isochronous transfer and asynchronous transfer in which data is transmitted to the second node in one of the first mode and the second mode in which data before encoding or data after encoding is transmitted in a mixed communication mode. In the first mode, when the possible transmission means and the coding method by the coding means are the coding methods corresponding to the decoding means provided in the second node, in the second mode when not supported Control means for controlling said transmitting means so as to transmit data in a second mode. 15. The data communication system according to claim 14, wherein said transmitting means is means for transmitting said data by isochronous transfer. 16. The data communication system according to claim 14, wherein said data is image data. 17. The data communication according to claim 14, wherein the control unit determines whether the communication destination node supports the encoding system by the encoding unit by communication using isochronous transfer. system. 18. The data communication system according to claim 14, wherein said transmitting means is means for performing transmission conforming to the IEEE 1394 standard. 19. The method according to claim 19, wherein the control unit determines that the communication destination node is compatible with the encoding method by the encoding unit when there is no appropriate response by the communication by the synchronous transfer. The data communication system according to claim 17, wherein: 20. The data communication system according to claim 19, wherein the appropriate reply is a reply within a predetermined period. 21. Does the first node have means for decoding data encoded by the encoding means for the second node before transmitting data to the second node? 15. The data communication system according to claim 14, wherein it is determined whether the data is to be transmitted while being encoded or to be transmitted after being decoded, based on an inquiry and a response from the second node. 22. A first node comprising encoding means and storage means for storing program information for decoding data encoded by the encoding means, and encoding the encoded data based on the program information. A data communication system connected to a second node for decoding, wherein the first node encodes data in a predetermined method, and encodes data in an encoded state. Isochronous transfer and asynchronous transmission of data to a second node in one of a first mode for transmitting and a second mode for transmitting data before encoding or data after encoding in a mixed communication mode. The first mode is used in the case where the transmitting means capable of transmission and the coding method by the coding means are the coding methods corresponding to the decoding means provided in the second node. Data communication system and a controlling means for controlling said transmission means to transmit the data in the second mode to the second mode to. 23. The first node transmits, to a second node, forward gram information for decoding data encoded by the encoding unit before transmitting data to the second node. 23. The data communication system according to claim 22, wherein an inquiry is made as to whether or not to transmit the program information together with data, based on a response from the second node. 24. The apparatus according to claim 22, wherein said first node further comprises an image pickup means for photographing an image, and said second node further comprises an output means for printing out received data. The data communication system according to any one of the above. 25. A data communication method for transmitting data encoded by a predetermined method, comprising: a first transmission step of transmitting program information including a decoding procedure of decoding encoded data; A data communication method, comprising: a second transmission step capable of performing isochronous transfer and asynchronous transfer, which transmits transmitted data. 26. A storage medium for storing a data communication program for transmitting data encoded by a predetermined method, wherein the program transmits program information including a decoding procedure for decoding the encoded data. A storage medium comprising: a code of a first transmission step; and a code of a second transmission step capable of transmitting coded data and capable of isochronous transfer and asynchronous transfer. 27. A storage medium for storing a data communication program for transmitting data encoded by a predetermined method, wherein the program is transmitted from a communication destination node to a node encoded by the predetermined method. Acquires information indicating whether or not it has program information for decoding data, and if so, transmits the encoded data as it is, and if not, encodes it. A storage medium including a code for transmitting encoded data and program information for decoding encoded data.