JPH11112533A - Data communication system, data communication method, data communication node and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer data efficiently independently of whether or not a reception node has a decoder. SOLUTION: The data communication system is realized, where video data are directly transferred from, e.g. a recording and reproducing device 1 to printers 3-5 via a 1394 serial bus and print-processed in the printers 3-5 without the need for processing by a PC. Thus, the user quickly conducts print processing desired to be conducted with priority independently of the processing capability and the operating state of the PC. In this case, compressed data are transferred to a printer having a decoder to improve the transfer efficiency and non-compensation data after expansion are transferred to a printer having no decoder so as to transfer data smoothly even to pluralities of devices connecting to a network and having difference from the decode function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system, a data communication method, a data communication node, and a recording medium, and more particularly to a data communication system using a communication control bus capable of communicating a control signal and various data in a mixed manner. The present invention is suitable for use in a system in which a plurality of electronic devices are connected to perform data communication between the electronic devices.

[0002]

2. Description of the Related Art Conventionally, a personal computer (hereinafter, referred to as a PC) and its peripheral devices are connected to each other using a digital interface (hereinafter, referred to as a digital I / F) such as SCSI which is a general-purpose interface for a small-sized computer. Communication was taking place. A digital camera or a digital video camera is also one of the peripheral devices as an image input unit to the PC.

In recent years, the technology in the field of capturing still images and moving images taken by a digital camera or video camera into a PC, storing the images on a hard disk, and performing color printing with a printer has been advanced, and the number of users has increased. ing. When outputting the captured image data from a PC to a printer or hard disk, the above SCSI
The data communication is performed via the above-mentioned method. In order to transmit information having a large data amount such as image data, a digital I / F having a high transfer data rate and versatility is required.

Conventionally, a configuration is generally used in which each peripheral device is connected to a PC serving as a host, and various processes relating to internal and external connection devices of the PC are performed by the PC. For example, when printing image data captured by a digital camera or the like with a printer, processing is generally performed in such a manner that the image data is once taken into a PC, edited using each application, and then output to a printer. It is being done.

[0005]

However, the SCSI which is a typical digital I / F mentioned in the above conventional example has a low transfer data rate and a thick cable for parallel communication. There are restrictions on the types and number of peripheral devices to be used, connection methods, and the like, and inconveniences in many aspects have been pointed out.

Normally, many peripheral devices can be connected to the PC, and the load on the PC becomes very large due to the transfer processing between these peripheral devices and the PC and the data processing inside the PC. . For example, when a user wants to print an image with priority, it is necessary to perform processing after image data is once imported to a PC.
The printing speed may be reduced depending on the processing capacity and situation of the printer.

As described above, in the conventional configuration, there is a problem that the efficiency of the process desired by the user is deteriorated due to the trouble of data transfer between the PC and the peripheral device and the processing status of the PC.

Conventionally, there are few printers which have a decoding function in the printer. this is,
This is also because a printer generally prints uncompressed image data output from a PC. A special printer device such as a video printer which does not connect a PC between the video device and the printer employs a wireless or I / O cable as a medium for exchanging information between the video device and the printer. Even when this is used, transfer as analog or uncompressed image data is common, and many of them are not said to have excellent transfer efficiency.

[0009] That is, when printing compressed video data and the like and transferring the compressed data to a printer, the transfer efficiency can be greatly improved. However, such an apparatus is not generally used. The present invention has been made to solve the above-described problems, and has as its object to enable efficient data transfer regardless of whether a receiving node includes a decoder.

[0010]

For example, a data communication system according to the present invention is a data communication system for transferring data from a first node to another node via a serial bus using the DS-Link system. The first node has a configuration for compressing and transferring data according to a predetermined compression method, and includes means for transferring compressed data and means for transferring uncompressed data during data transfer. And At this time, the first node executes both the transfer of the compressed data and the transfer of the uncompressed data having the same data content within the cycle period, and repeats this in each cycle until the end of each transfer. Here, the first node may be a video recording / reproducing device.
Further, the other node may be a printer. Further, the first node and the other node are connected to the DS-
They may be directly connected by a serial bus using the Link system. Further, an IEEE 1394 serial bus using the DS-Link system may be used.

In other words, the present invention solves the above-mentioned problems which the conventional digital I / F has.
General-purpose digital I / F (for example, IEEE
E1394-1995 high-performance serial bus) is used to realize inter-device data communication when a PC, printer, other peripheral device, or recording / reproducing device such as a camera-integrated digital VTR is connected in a network configuration. For example, a P which can directly transfer video data from a recording / reproducing device to a printer and perform print processing.
A data communication method that does not require processing in C is realized, thereby improving printing efficiency.

With such a configuration, the transfer of compressed video data is indispensable to improve the transfer efficiency of data having a large amount of information such as video data.
However, in the case of each device to which video data is transferred, for example, a printer, a network in which a printer includes a decoder and a printer that does not include a decoder may be configured. Realizes comfortable data transfer even under the configuration.

That is, according to the present invention, data communication and print processing for image printing can be performed without going through the processing of a PC which generally hosts a network. The print processing that the user preferentially performs can be quickly performed without being affected, and the load on the PC caused by the print data processing can be eliminated.

Further, with respect to video data transferred from the recording / reproducing apparatus, in particular, still image data for printing or screen display, a device to which data having the same content is transferred, such as a printer or a monitor, is used. When a plurality of devices exist, transfer and receive the compressed data to improve the transfer efficiency for a device having a decoder,
Decompressed uncompressed data can be transferred and received for devices that do not have a decoder, and transfer can be performed smoothly to multiple devices connected to the network with different decoding functions. I can do it.

Further, in a serial bus network composed of a plurality of devices, all devices capable of receiving video data from the recording / reproducing device, which is the first node of the present invention, support the video data compression method. When a possible decoder is provided, the transfer efficiency is further improved by not transferring uncompressed data.

[0016]

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, a digital I / F for connecting each device is provided.
Since a serial bus using the DS-Link system, for example, an IEEE 1394 serial bus is used,
The EE1394 serial bus will be described in advance.

<< Overview of IEEE 1394 Technology >> With the advent of home digital VTRs and DVDs (Digital Video Discs), support for transferring data with a large amount of information in real time, such as video data and audio data, has been provided. Is needed. In order to transfer such video data and audio data in real time, and to transfer it to a personal computer (PC) or transfer it to other digital devices, it has the necessary transfer function and can transfer data at high speed An interface is needed. An interface developed from such a viewpoint is an IEEE 1394-1995 serial bus (Hi
gh Performance Serial Bus: 1394 serial bus).

FIG. 11 shows an example of a network system configured using a 1394 serial bus. This system includes a plurality of devices A, B, C, D, E, F, G, H
Between A and B, between A and C, between B and D, and between D and E
, C-F, C-G and C-H are each 13
It is connected by a twisted pair cable of 94 serial bus. These devices A to H are, for example, PC, digital VTR, DVD, digital camera, hard disk,
Monitor. The connection method between the devices is such that the daisy chain method and the node branch method can be mixed, and a connection with a high degree of freedom is possible.

Each of the devices A to H has its own unique ID.
One network is configured in a range connected by four serial buses. Just by sequentially connecting each digital device with a single 1394 serial bus cable, each device plays a role of relay and constitutes one network as a whole. Also, 13
The Plug & Play function, which is a feature of the 94 serial bus, has a function of automatically recognizing the device and recognizing the connection status when the cable is connected to the device.

In the system shown in FIG. 11, when a certain device is deleted or newly added from the network, the bus is automatically reset to reset the network configuration up to that time. Then, rebuild a new network. With this function, the configuration of the network at that time can be constantly set and recognized.

The data transfer rate is 100/200.
/ 400 Mbps, so that a device having a higher transfer rate supports a lower transfer rate and is compatible.

As the data transfer mode, asynchronous data such as control signals (Asynchronous data:
Asynchronous transfer mode for transferring synchronous data (Async data), and isochronous transfer mode for transferring synchronous data (Isochronous data: hereinafter Iso data) such as real-time video data and audio data. The Async data and Iso data are stored in each cycle (usually one cycle = 125
μS), following the transfer of the cycle start packet (CSP) indicating the start of the cycle, the transfer is performed in a mixed manner within the cycle while giving priority to the transfer of the Iso data.

Next, the components of the 1394 serial bus are shown in FIG. The 1394 serial bus has a layer (layer) structure as a whole. As shown in FIG. 12, the most hardware is a 1394 serial bus cable. Further, there is a connector port to which a connector of the cable is connected, and a physical layer and a link layer are provided as hardware on the connector port.

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 reads and writes data.
Issue a command such as ite. The serial bus management is a part that manages the connection status and ID of each connected device, and manages node control and network configuration. The functions of a bus manager and an isochronous resource manager described later are included in this serial bus management.

The hardware section and the firmware section constitute a substantial 1394 serial bus.
The application layer of the software department is
It depends on the software used and is a part that defines how data is to be placed on the interface, and is defined by a protocol such as the AV protocol. The above is the configuration of the 1394 serial bus.

Next, FIG. 13 shows an address space in the 1394 serial bus. Each device (node) connected to the 1394 serial bus always has a unique 6
It has a 4-bit address. By storing this address in the ROM, the node address of the user or the other party can always be recognized, and communication specifying the other party can be performed.

The addressing of the 1394 serial bus is based on the IEEE 1212 standard, and the first 10 bits are used for specifying the bus number.
The next 6 bits are used for specifying the node ID number. Then, the remaining 48 bits become the address width given to the device, and can be used as a unique address space. Of these, the last 28 bits store information such as identification of each device and designation of use conditions as a unique data area.

The above is the outline of the technology of the 1394 serial bus. Next, the technical portion 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. 14 is a sectional view of a 1394 serial bus cable. In the 1394 serial bus, 2
A power supply line is provided in addition to the 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 specified to be 8 to 40 V, and the current is specified to be 1.5 A DC maximum current.

<< DS-Link Coding >> FIG.
4 is a time chart for explaining a DS-Link encoding system of a data transfer format adopted in a 94 serial bus. In the 1394 serial bus, DS
-A Link (Data / Strobe Link) coding method is adopted.

This DS-Link coding method 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. As shown in FIG. 15, on the receiving side,
The clock can be reproduced by taking the exclusive OR of the transmitted data and the strobe signal.

Advantages of using the DS-Link coding method include higher transfer efficiency compared to other serial data transfer methods, and a reduced circuit size of the controller LSI because a PLL circuit is not required.
Since there is no need to send information indicating the idle state when there is no data to be transferred, the transceiver circuit of each device can be put into the sleep state, and power consumption can be reduced.

<< Sequence of Bus Reset >> In the 1394 serial bus, each connected device (node) is given a node ID and recognized as a network configuration. When this network configuration changes,
For example, when 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., and it is necessary to recognize a new network configuration, each node that has detected the change transmits a bus reset signal on the bus. Then, a mode for recognizing a new network configuration is entered. The method of detecting the change at this time is performed by detecting a change in the bias voltage on the 1394 port substrate.

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. introduce. After all the nodes finally detect the bus reset signal, the bus reset is activated. The bus reset is activated by issuing a command directly to the physical layer by host control from a protocol, in addition to the above-described activation by hardware detection due to cable insertion / removal or network abnormality or the like.

When the bus reset is activated, the data transfer is temporarily suspended, and the data transfer during this time is awaited. Then, after the end of the bus reset, the data transfer is restarted under the 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. The general sequence from the bus reset to the determination of the node ID at this time will be described with reference to the flowcharts of FIGS. 23, 24, and 25.

The flowchart of FIG. 23 shows a series of bus operations from the occurrence of a bus reset to the determination of a node ID until data transfer can be performed.
First, in step S101, it is constantly monitored whether or not a bus reset occurs in the network. If a bus reset occurs due to power ON / OFF of a node, the process proceeds to step S102.

In step S102, a parent-child relationship is declared between the directly connected nodes in order to know the connection status of a new network from the reset state of the network. Then, step S103
In step S104, when it is determined that the parent-child relationship has been determined between all the nodes, one root node is determined in step S104. Until the parent-child relationship is determined between all nodes, the parent-child relationship is declared in step S102, and the root node is not determined.

After the route is determined in step S104, the operation of setting a node ID for giving an ID to each node is performed in step S105. This node I
The setting of D is performed in a predetermined node order, and the setting operation is repeatedly performed until IDs are given to all the nodes. Finally, in step S106, IDs are assigned to all nodes.
Is set, the new network configuration is recognized on all nodes.
In step S107, data transfer between nodes can be performed, and data transfer is started.

When the state of step S107 is reached, the process returns to step S101 to enter a mode for monitoring the occurrence of a bus reset again. If a bus reset occurs, the setting operations from step S102 to step S106 are repeatedly performed. The above is the description of the flowchart of FIG. 23. The flowchart of FIG. 23 illustrates the procedure from the bus reset to the route determination and the procedure from the route determination to the end of the ID setting in more detail. 24 and FIG.

First, the flowchart of FIG. 24 will be described. If it is determined in step S201 that a bus reset has occurred, the network configuration is reset once. In step S201, whether or not a bus reset occurs is constantly monitored.

Next, in step S202, as a first step of the operation for re-recognizing the reset connection state of the network, it is shown that each device is a leaf (a node having connection to only one port). Set a flag. Further, in step S203, each device checks how many ports its own device is connected to other nodes.

In step S204, according to the recognition result of the number of undefined ports, undefined (parent-child relationship is not determined) in order to start declaration of parent-child relationship from now on.
Check the number of ports. Immediately after a bus reset, the number of ports =
Although it is the number of undefined ports, as the parent-child relationship is determined, the number of undefined ports detected in step S204 changes.

First, immediately after a bus reset, only a leaf can declare a parent-child relationship. Whether it is a leaf or not can be known by checking the number of ports in step S203. In step S205, the leaf declares "I am a child and the other is a parent" to the node connected thereto, and ends the operation. Step S
The node that is recognized as a branch having connections to a plurality of ports in 203 immediately after the bus reset is determined in step S204 as the number of undefined ports> 1, so that the step S20
Then, the flag “branch” is set.
Then, 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,
The branch that has received it in step S207 returns to step S204 as appropriate to check the number of undefined ports. Here, if the number of undefined ports is 1, the process proceeds to step S20 for the node connected to the remaining port.
5 makes it possible to declare "I am a child". Even if the number of undefined ports is confirmed in the second and subsequent steps in step S204, the branch having the number of undefined ports of 2 or more waits again in step S207 to accept a "parent" from a leaf or another branch.

Finally, if any one branch or exceptional leaf (because it did not operate quickly even though a child declaration can be made) becomes zero as a result of determining the number of defined ports at the end of step S204, This means that the declaration of the parent-child relationship of the entire network has been completed. The only node whose undefined port number becomes zero (all determined as parent ports) is flagged as a root in step S208, and recognized as a root in step S209.

Thus, the process from the bus reset shown in FIG. 24 to the declaration of the parent-child relationship between all the nodes in the network is completed. Next, the flowchart of FIG. 25 will be described.

First, the flag information of each node such as leaf, branch, and root is set in the sequence of FIG. 24, and based on this, each is classified in step S301. It is from the leaf that the ID can be set first as an operation of giving an ID to each node. That is, the IDs are set in ascending order of leaf → branch → route (node number = 0).

If the flag information is leaf, first, in step S302, the number N (N is a natural number) of leaves existing in the network is set. Thereafter, step S30
In 3, each leaf requests that the route be given an ID. If there are a plurality of requests, the route performs arbitration (operation of arbitrating one) in step S304, and assigns an ID number to one of the nodes that has won the arbitration in step S305. The losing node is notified of the failure result.

In step S306, it is confirmed whether or not the leaf has succeeded in acquiring the ID. If the leaf has failed in acquiring the ID, the flow returns to step S303 to issue an ID request again, and the same operation is performed until the ID is acquired. To repeat. The leaf from which the ID has been acquired proceeds to step S307, and transfers the ID information of the node to all nodes by broadcasting. When the broadcast of one node ID information ends, the number N of remaining leaves is reduced by one in step S308.

Then, in step S309, the number N of remaining leaves is determined.
The operation from the ID request of No. 3 is repeated. Eventually, when all the leaves broadcast the ID information, the determination result in 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 case of the leaf.

First, in 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 to give an ID to the root. On the other hand, the root performs arbitration in step S312, and assigns IDs from the branch having won the arbitration in order from the next youngest number given to the leaf. Step S3
At 13, the root notifies the branch that issued the ID request of ID information or a failure result.

In step S314, it is confirmed whether or not the branch has succeeded in acquiring the ID. If the branch in which the acquisition of the ID has failed has failed, the flow returns to step S311 to issue an ID request again, and the same operation is performed until the ID is acquired. repeat. I
The branch that has obtained D proceeds to step S315,
The ID information of the node is transmitted to all nodes by broadcasting. When the broadcast of one node ID information ends, the number M of remaining branches is reduced by one in step S316.

Then, in step S317, the number M of the remaining branches is determined.
The operation from the ID request in 311 is repeated until all branches finally broadcast ID information. When all the branches have acquired the node IDs, the determination result of step S317 becomes M = 0, and the branch I
The D acquisition mode also ends.

At this point, since only the root node has not obtained the ID information at the end, step S
Proceeding to step 318, the smallest number among the numbers that have not been given so far is set as its own ID number, and step S31 is performed.
9 broadcasts the route ID information. Thus, as shown in FIG. 25, the procedure from the determination of the parent-child relationship to the setting of the IDs of all the nodes is completed.

Next, the operation in the actual network shown in FIG. 16 as an example will be described with reference to FIG. In FIG. 16, nodes A and C are directly connected below the root node B.
Has a hierarchical structure in which a node D is directly connected to a lower level of the node D, and a node E and a node F are directly connected to a lower level of the node D. The procedure for determining the hierarchical structure, the root node, and the node ID will be described below.

That is, after the bus reset, a parent-child relationship is declared between ports directly connected to 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 the example of FIG. 16, it is the node A that first declared the parent-child relationship after the bus reset. Basically, a parent-child relationship can be declared from the leaf.
This confirms that you are at the edge of the network because you can first know that you have only one port connection. Then, the parent-child relationship is determined from the node that has operated earlier in each leaf. In this manner, 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, node A-
B: child-parent, node ED: child-parent, node FD
A child-parent is determined between.

Further up in the hierarchy, among nodes (branches) having a plurality of connection ports, the parent-child relationship is declared further higher in order from the node that received the declaration of the parent-child relationship from another node. To go. In the example of FIG. 16, the node D first determines the parent-child relationship between DE and DF, and then declares the parent-child relationship for the node C. As a result, the child-parent relationship between the nodes DC is determined. Has been determined. The node C that has received the declaration of the parent-child relationship from the node D makes a declaration of the parent-child relationship to the node B connected to another port, and determines that the node C-B is a child-parent. .

In this way, a hierarchical structure as shown in FIG. 16 is formed, and the node B that 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. 16, 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, declares a parent-child relationship to other nodes at an earlier timing. If so, the root node may have moved to another node. In other words, another node may also be a root node depending on the timing at which the declaration is transmitted, and the root node is not always constant even in the same network configuration.

When the root node is determined, the process enters a mode for determining each node ID. Here, all nodes notify their determined node IDs to all other nodes (broadcast function). The self ID information is
It includes its own node number, information on the connected position, the number of ports it has, the number of connected ports, information on the parent-child relationship of each port, and the like.

As a procedure for assigning node ID numbers, first, nodes can be started from nodes (leaves) connected to only one port, and node numbers = 0, 1, 2,... . The node that has obtained the node ID transmits information including the node number to each node by broadcast. By this, the ID
It is recognized that the number is "assigned".

When all the leaves have acquired their own node IDs, the process moves on to the branch, and the node ID number following the leaf is assigned to each node. Similarly to the leaf, the node ID information is broadcast sequentially from the branch to which the node ID number is assigned, and finally, the root node broadcasts its own ID information. That is, the root always owns the maximum node ID number. As described above, the node ID of the entire hierarchical structure
Has been assigned, the network configuration has been rebuilt,
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 of the individually connected devices relays the transferred signal to transmit the same signal to all devices in the network, collision of transmission packets occurs. Arbitration is necessary to prevent This allows only one node to transfer at a given time.

As a diagram for explaining arbitration, FIG. 17A shows a state of a bus use request, and FIG.
FIG. 7 (b) shows a state of permission for bus use. Hereinafter, FIG.
7, arbitration will be described. When the arbitration starts, one or more nodes each issue a bus use request toward the parent node. Nodes C and F in FIG. 17A are nodes that have issued requests for the right to use the bus.

The parent node (node A in FIG. 17A) that has received the request for the right to use the bus issues a request for the right to use the bus toward the parent node (that is, relays the request for the right to use the bus). Do). This request is finally delivered to the arbitrating 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.
The node that wins the arbitration is given permission to use the bus. In FIG. 17B, use permission is given to the node C,
Node F has been denied use.

To the node that has lost arbitration, a DP (data prefix) packet is sent to notify that the node has been rejected. The rejected node use request waits until the next arbitration. As described above, the node that wins the arbitration and obtains 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.
The bus must be idle before a node can initiate a data transfer. In order to recognize that the data transfer that has been performed earlier is completed and the bus is currently idle, a predetermined idle time gap length (for example, a subaction By passing the gap, each node determines that its own transfer can be started.

For this reason, first, in step S401, it is determined whether a predetermined gap length corresponding to each data to be transferred, such as Async data or Iso data, has been obtained. Unless the specified gap length is obtained, the request for the right to use the bus required to start the transfer cannot be made.
Wait until a predetermined gap length is obtained.

When a predetermined gap length is obtained in step S401, it is determined in step S402 whether or not there is data to be transferred. If so, the flow advances to step S403 to use the right to use the bus to transfer the data. Issue a request for the right to use the bus to the route so as to secure the route. At this time, 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, in step S404, when the route receives one or more bus use requests in step S403, the route checks in step S405 the number of nodes that have issued use requests. If the selection value in step S405 is the number of nodes = 1 (one node that has issued the bus use right request), the immediately subsequent bus use permission is given to that node.

If the selection value at step S405 is the number of nodes> 1 (the number of nodes that have issued use requests is plural),
In step S406, the root performs an arbitration operation to determine one node to which use permission is given. This arbitration work is fair, and the same node does not always obtain permission every time, and the right is equally given.

Next, in step S 407, a selection is made from among a plurality of nodes that have issued use requests, to divide the route into one node whose use has been granted due to arbitration and another node that has lost the arbitration. Do. Here, the route is one node that has been arbitrated and has been authorized to use, or step S40.
In step S408, a permission signal is sent to a node that has obtained use permission without arbitration with the use request node number = 1 from the selection value of 5 in step S408. The node that has received the permission signal starts transferring data (packets) to be transferred immediately after receiving the permission signal.

The nodes which have lost the arbitration in step S406 and are not permitted to use the bus are provided in step S40.
DP (data prefix) indicating arbitration failure at 9
) Packets are sent from the route. The node that has received the request returns to step S401 to issue a bus use request for performing the transfer again, and waits until a predetermined gap length is obtained. The above is the description of the flowchart showing the flow of arbitration.

<< Cycle Master >> The cycle master in the components is a node that periodically generates a cycle start signal. The cycle start signal is called a cycle start, and is a cycle synch source (typically 125 μS).
Is transmitted from the cycle master to each node as a cycle start packet at a special interval set by. The cycle start time is usually every 125 μS, but depending on the transfer state, transmission may be delayed with a delay of 125 μS.

<< Bus Manager >> The bus manager is a function included in the serial bus management shown in FIG. 12, which includes advanced power management, optimization of serial bus performance, topology management, and data management. This node has functions such as transfer rate control, cycle master control and performance optimization, and can provide a management function to other nodes. At the same time, the node serving as the bus manager
It can also be a resource manager node.

<< Isochronous resource manager >>
The resource manager is a node having a function of managing assignment of an isochronous data transfer band and a channel number in isochronous transfer as a function included in serial bus management. The only isochronous resource manager that performs this management exists on the bus, and after the bus initialization phase, one is dynamically selected from a plurality of nodes having the isochronous resource manager function.

The determination of the bus manager is also made by this isochronous resource manager node. In a configuration where there is no bus manager on the bus, bus management such as power management and cycle master control is performed.
Some functions of the manager may be performed by the isochronous resource manager.

<< Asynchronous Transfer >> The asynchronous transfer is an asynchronous transfer. FIG. 18 shows a temporal transition state in the asynchronous transfer. The first subaction gap shown in FIG. 18 indicates an idle state of the bus. When the idle time reaches a certain value, the node desiring data transfer determines that the bus can be used and executes arbitration for acquiring the bus.

When the use of the bus is obtained by arbitration, data transfer is executed in the form of a packet.
After the data transfer, the node that has received the data transmits a reception confirmation return code a, which is a reception result for the transferred data.
The transfer is completed by returning ck after a short gap of ackgap and responding or sending a response packet. The acknowledgment return code ack is composed of 4-bit information and a 4-bit checksum, and includes information such as success, busy status, and pending status, and is immediately returned to the source node. Is done.

Next, FIG. 19 shows an example of the packet format of the asynchronous transfer. The packet has a header part in addition to the data part and the data CRC for error correction. In the header portion, a destination node ID, a source node ID, a transfer data length, various codes, and the like as shown in FIG. 19 are written and transferred. 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 transferred packet. The above is the description of the asynchronous transfer.

<< Isochronous (Synchronous) Transfer >> Isochronous transfer is synchronous transfer. The isochronous transfer, which can be said to be the greatest feature of the 1394 serial bus, is a transfer mode suitable for transferring data that requires real-time transfer, such as multimedia data such as VIDEO video data and audio data. In contrast to the asynchronous (asynchronous) transfer, which is a one-to-one transfer, in the isochronous transfer, a packet is uniformly transferred from one transfer source node to all other nodes by a broadcast function.

FIG. 20 is a diagram showing a temporal transition state in the isochronous transfer. The isochronous transfer is executed at regular intervals on the bus. This time interval is called an isochronous cycle. The isochronous cycle time is 125 μS. The cycle start packet indicates the start time of each cycle, and plays a role of adjusting the time of each node. It is the cycle master that transmits the cycle start packet, and after a predetermined idle period (subaction gap) has elapsed after the transfer in the previous cycle is completed, a cycle start signal indicating the start of this cycle. Send a packet. The time interval at which this cycle start packet is transmitted is 125 μS.

FIG. 20 shows channels A, B,
As indicated by the channel C, a plurality of types of packets can be transferred in one cycle by giving a channel ID. This allows real-time transfer between a plurality of nodes at the same time. At this time, the receiving node takes in only the data of the channel ID desired by itself. The channel ID does not represent the address of the transmission destination, but merely gives a logical number for the data. Thus, the transmission of a packet will be forwarded by broadcast from one source node to all other nodes.

Prior to the packet transmission in the isochronous transfer, arbitration is performed in the same manner as in the asynchronous transfer. However, since it is not one-to-one communication as in asynchronous transfer, there is no acknowledgment return code ack in isochronous transfer. The iso gap (isochronous gap) shown in FIG. 20 indicates 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. 21 shows an example of a packet format of the isochronous transfer. Each packet divided into each channel has a header part in addition to the data part and the data CRC for error correction. The header portion includes a transfer data length, a channel number, other various codes, and a header CR for error correction as shown in FIG.
C and the like are written, and transfer is performed. 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. 22 shows a temporal transition of a transfer state on a bus where isochronous transfer and asynchronous transfer are mixed. 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. .

In the general bus cycle shown in FIG. 22, at the start of cycle #m, a cycle start packet is transferred from the cycle master to each node. As a result, each node performs time adjustment, waits for a predetermined idle period (isochronous gap),
A node that should perform isochronous transfer performs arbitration and starts packet transfer. In FIG. 22, the channel e, the channel s, and the channel k are sequentially transferred in an isochronous manner.

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 are completed, the asynchronous transfer can be performed. That is, when the idle time reaches the subaction gap in which the asynchronous transfer can be performed, it is determined that the node that wants to perform the asynchronous transfer can shift to the execution of the arbitration.

However, during the period in which the asynchronous transfer can be performed, a sub-action gap for starting the asynchronous transfer is provided between the end of the isochronous transfer and the time (cycle synch) at which the next cycle start packet should be transferred. Only when obtained.

In cycle #m in FIG. 22, isochronous transfer for three channels and asynchronous transfer (including ack) for two packets (packet 1 and packet 2) are performed thereafter. After the asynchronous packet 2, it is time to start cycle # m + 1 (cycle synch), so the transfer in cycle #m ends here.

However, the time (cy) at which the next cycle start packet should be transmitted during the asynchronous or synchronous transfer operation
If cle synch is reached, the data transfer is not forcibly interrupted, and after waiting for an idle period after the transfer is completed, the cycle start packet of the next cycle is transmitted. That is, when one cycle continues for 125 μS or more, the next cycle is shortened by that much from the reference 125 μS. Thus, the isochronous cycle can be exceeded and shortened on the basis of 125 μS.

However, the isochronous transfer is always executed whenever necessary for maintaining the real-time transfer, and the asynchronous transfer may be transferred to the next and subsequent cycles due to the shortened cycle time. The information including such delay information is managed by the cycle master. The above is the description of the IEEE 1394 serial bus.

Now, a description will be given of a case where each device is connected by a 1394 serial bus cable as shown in FIG.
The bus configuration according to the present embodiment includes a recording / reproducing device 1 such as a digital camera or a digital VTR connected to a 1394 serial bus drawn by a solid line as shown in FIG.
And the connection configuration with the printer devices 3, 4, and 5. The monitor 2 can display moving images or still images, and the printers 3, 4, and 5 can print still image data.

The network shown in FIG. 1 is a group of devices as an example. The connection configuration may be such that each device shown in FIG. 1 is connected to an arbitrary position. Not done. Further, the configuration may be such that each device is connected to another digital device first. Also,
A configuration in which more recording / reproducing devices and printers are connected than shown in the figure may be used.

Further, even with devices other than those shown in FIG.
C, external storage device such as hard disk, CD, DVD
Any device that can form a network with a 1394 serial bus, such as an output device, etc., may be connected. The monitor 2 and the printers 3, 4, and 5 may or may not have a decoding function that can support the recording / reproducing device 1.
In the first embodiment, in particular, it is assumed that the printers 3, 4, and 5 have a configuration in which some of the printers are compatible with the recording / reproducing apparatus 1 and some of which are not.

That is, although the configuration of the printers 3, 4, and 5 in the first embodiment is shown as a block diagram in FIGS. 5 and 6, the printer 3 is compatible with the data compression method in the recording / reproducing apparatus 1. It is assumed that the printers 4 and 5 have a possible decoding function, and that the printers 4 and 5 have no decoding function or have only decoders that cannot support the compression method of the recording / reproducing apparatus 1.

With the bus configuration described above with reference to FIG. 1 as a background, the first embodiment of the present invention will be described with reference to block diagrams 3 to 6 shown below.
An embodiment will be described. FIG. 3 is a diagram showing a configuration of the recording / reproducing apparatus 1 shown in FIG. In FIG.
Reference numeral 6 denotes an imaging system, 7 denotes an A / D converter, 8 denotes a video signal processing circuit, 9 denotes compression in recording according to a predetermined algorithm,
This is a compression / expansion circuit that performs expansion during reproduction.

Reference numeral 10 denotes a recording / reproducing system including a magnetic tape or optical (magnetic) disk as a recording medium, a solid-state memory, and a recording / reproducing head thereof, 11 denotes an operation unit for inputting an instruction,
12 is a system controller, 13 is a D / A converter, 14 is an EVF as a display unit, 15 is an image memory for temporarily storing video data to be transferred uncompressed, 16
Denotes a memory control unit that controls writing / reading of the image memory 15.

Reference numeral 17 denotes an image memory for temporarily storing video data to be compressed and transferred, and reference numeral 18 denotes the image memory 17.
A memory control unit for controlling writing / reading of data, 19 is a data selector, 20 is an I / F of a 1394 serial bus
Department. The 1394 I / F 20 has one port connected to the monitor 2 and the other port connected to the printer 5 by a 1394 cable.

FIG. 4 is a diagram showing a configuration of the monitor device 2 shown in FIG. 4, reference numeral 21 denotes a 1394 I / F unit mounted on the monitor 2, and reference numeral 22 denotes a compression / expansion circuit 9 shown in FIG.
, A decoding circuit (decoder) capable of expanding video data compressed according to a predetermined algorithm, 23 is a D / A converter, 24 is a CRT unit, 25 is a system controller of the monitor 2, and 26 is an operation unit of the monitor 2. .

Although not shown, the monitor 2 may be provided with a receiving circuit and the like for receiving and displaying a television signal. 1394 I / F21 is
One port is connected to the recording / reproducing apparatus 1 and another port is connected to the printer 3 by a 1394 cable.

FIG. 5 is a diagram showing a configuration of the printer 3 shown in FIG. 5, reference numeral 31 denotes a 1394 I / F unit in the printer 3, reference numeral 32 denotes a data selector, reference numeral 33 denotes a decoding circuit (decoder) capable of expanding video data compressed by the compression / expansion circuit 9 of FIG. Denotes an image processing circuit for a print image, and 35 denotes a memory for forming a print image.

Reference numeral 36 denotes a printer head, 37 denotes a driver for driving the printer head 36 and feeding paper, and the like.
Reference numeral 38 denotes a printer controller as a control unit of the printer 3, and 39 denotes an operation unit of the printer 3. 1394 I / F
Reference numeral 31 indicates that one port is connected to the monitor 2 and the other port is connected to the printer 4 by a 1394 cable.

FIG. 6 is a diagram showing a configuration of the printer 4 and the printer 5 shown in FIG. In FIG. 6, reference numeral 40 denotes a 1394 I / F in the printer 4 or 5;
41, a data selector, 42, an image processing circuit for a print image, 43, a memory for forming a print image, 44, a printer head, 45, a driver for driving the printer head 44 and paper feeding, and 46, A printer controller as a control unit of the printer 4 or 5;
Reference numeral 7 denotes an operation unit of the printer 4 or 5.

In the printer 4, the 1394 I / F 40
Are connected to the printer 3 from one port by a 1394 cable. In the printer 5,
The 1394 I / F 40 is connected to the recording / reproducing apparatus 1 from one port by a 1394 cable. Since the functions of the printer 4 and the printer 5 are the same, the block diagram is shown only in FIG.

The difference between the printer 3 and the printers 4 and 5 is that a decoding circuit (decoder) capable of expanding video data compressed by a compression / expansion circuit 9 according to a predetermined algorithm.
It is assumed that only the presence / absence of 33 and the presence / absence of processing related to the decoder 33 are the same, and the other print functions and operations are the same.

Next, the operation of the first embodiment will be described step by step with reference to these block diagrams 3 to 6. First,
In FIG. 3, at the time of recording by the recording / reproducing apparatus 1, a video signal captured by the imaging system 6 is digitized by an A / D converter 7, and then subjected to video processing by a video signal processing circuit 8.

One of the outputs of the video signal processing circuit 8 is converted back to an analog signal by the D / A converter 13 as a video being captured, and is displayed by the EVF 14. Other outputs are subjected to compression processing by a compression / expansion circuit 9 according to a predetermined algorithm, and are recorded on a recording medium (not shown) by a recording / reproducing system 10. Here, the predetermined compression processing is a typical MPEG method as a moving image compression method and a typical JPEG method as a still image compression method. In addition, in digital VTRs for home use, DCT (discrete cosine transform) is used as a band compression method.
And a compression method based on VLC (Variable Length Coding).

At the time of reproduction, the recording / reproducing system 10 reproduces a desired video from a recording medium (not shown). At this time, the desired video is selected based on the instruction content input from the operation unit 11 and is reproduced under the control of the system controller 12. Video data reproduced from a recording medium (not shown)
On the other hand, it is output to the image memory 17 as video data to be transferred to the bus in a compressed state. On the other hand, reproduced non-compressed video data is expanded and decompressed by the compression and decompression circuit 9 as uncompressed video data to be decompressed and transferred, and the resulting non-compressed data is output to the image memory 15.

The recording / reproducing apparatus 1 has a mode for recording a moving image,
In this embodiment, a still image may be recorded, or both a moving image and a still image may be recorded. Alternatively, the still image may be recorded with sound. When transferring an image of one frame extracted from an image or a moving image to another node for printing or displaying a still image, transferring the image data read from the recording medium from the image memory 17 while compressing the image data, and And transferring uncompressed video data obtained by expanding the same video data from the image memory 15 in parallel. At this time, the video data can be read out from both the image memories 15 and 17 and transferred in parallel. In the normal mode, it is only necessary to transfer the output of one of the memories 15 and 17.

Even if the compressed video data is transferred, a plurality of transfer destination devices do not always have decoders that can support the compression method. Therefore, by transferring the compressed data to a device equipped with the decoder, the transfer speed is increased, the transfer efficiency is improved, and uncompressed data is transferred to a device not equipped with the decoder. Transfer video data. This makes it possible to smoothly perform transfer and processing for printing in a network in which devices having decoders and devices not having decoders coexist.

When the reproduced video data is displayed on the EVF 14, the reproduced compressed video data is expanded by the compression / expansion circuit 9 and returned to the analog signal by the D / A converter 13. Output and displayed.

The image memories 15 and 17 are provided with a memory controller 16 controlled by the system controller 12, respectively.
The writing / reading is controlled by 18, and the output from the image memories 15, 17 is controlled according to a predetermined condition. The video data read from each of the image memories 15 and 17 is output to the data selector 19.

The system controller 12 controls the operation of each unit in the recording / reproducing apparatus 1. The system controller 12 outputs control command data to an externally connected device such as a printer, and outputs data from the data selector 19 to the 1394 I / F2.
0, a command can be transmitted to an external device through a 1394 serial bus.

The image memory 17 inputted to the data selector 19 is the same still image data as the contents of the data.
Compressed data from the image memory 15, uncompressed data from the image memory 15, and further, command data are classified and output to the 1394 I / F unit 20, and are output from the 1394 I / F 20 to 13.
Each data is transferred on the cable based on the specification of the 94 serial bus.

Here, in the present embodiment, the transfer is performed using the isochronous transfer method when transferring both the compressed and uncompressed still image data. When necessary command data is transferred, the transfer is performed by designating a transfer destination by using an asynchronous transfer method, and each is transferred on a bus. Further, the compressed still image data is set to an arbitrary channel A, and the non-compressed still image data is set to an arbitrary channel B, and is isochronously transferred. The classification of such a channel and the processing for transferring each data are described in 1394 I / F.
This is performed by the unit 20 and the system controller 12.

Here, FIG. 2 shows a temporal state transition diagram when still image data is transferred from the recording / reproducing apparatus 1 to the bus in the first embodiment. A channel (channel) A in each cycle of FIG. 2 is a packet of compressed still image data that is being transferred by the isochronous transfer method. Further, ch (channel) B is a packet of uncompressed still image data transferred by the isochronous transfer method.

Channel A and channel B packets are incorporated one by one into each cycle divided by the cycle start packet (cycle #m in FIG. 2).
To # m + 2), since the transfer of the compressed data of channel A ends earlier in cycle # m + 2,
After m + 3 and # m + 4, only the transfer of the channel B is performed, and this is continued until the transfer ends.

FIG. 2 shows a temporal cycle flow including a cycle start packet and an isochronous transfer.
The figure shows that command data and the like are packet-transferred using an asynchronous transfer method in an arbitrary cycle as needed. That is, the compressed still image packet and the non-compressed still image packet are classified by channel, multiplexed in a time division manner, and transferred on the bus for each cycle. Command data is multiplexed and transferred within an arbitrary cycle as needed as an Async packet. In the first embodiment, such a transfer form is assumed.

Such a series of transfer processing is controlled by the system controller 12 shown in FIG. 3, and a program describing the control procedure is stored in, for example, a ROM (not shown) in the system controller 12. in this case,
This ROM constitutes the recording medium of the present invention. The configuration of the recording medium is not limited to this. For example, as a recording medium for storing the above program, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-R
An OM, a magnetic tape, a nonvolatile memory card, or the like can be used.

As a device to which compressed and uncompressed still image data is transferred in this embodiment, there are a monitor 2 and printers 3, 4, and 5, as shown in FIG. These receiving devices are equipped with Iso data containing necessary video data.
Select the channel of the packet and receive it. As for Async packets such as command data, only those whose header is written to itself as a transfer destination node are fetched.

In the present embodiment, which of the iso packets of the same still image having different channels is to be received for compression or non-compression is set as follows.
That is, when a decoder included in the receiving device itself such as a printer can support the above-described compression method, it receives the channel A of the compressed image, and when the provided decoder cannot support the above-described compression method or does not have the decoding function itself. Is set to receive channel B of an uncompressed image.

The data selective reception processing at the receiving node is controlled by, for example, a controller at the receiving node. A program describing the control procedure is stored in, for example, a ROM (not shown) in the controller. Is stored. In this case, this ROM constitutes the recording medium of the present invention. The configuration of the recording medium is not limited to this, as in the case described above.

Next, the operation of the monitor 2 will be described with reference to FIG. The monitor 2 receives and displays moving images and still images transferred by the recording and reproducing device 1. Since the monitor 2 can also receive data with a large amount of information such as a moving image in real time, it is more convenient to provide a decoder that supports data compression and transfer. In the present embodiment, a decoding circuit (decoder) 22 capable of expanding video data compressed by the compression / expansion circuit 9 in the recording / reproducing apparatus 1 is provided.

Therefore, the monitor 2 is set so as to receive the channel of the compressed video packet (channel A in FIG. 2) and, under the control of the system controller 25, receives the channel of the compressed packet which has been isochronously transferred on the bus. The channel is received from the 1394 I / F 21. The compressed video data input from the 1394 I / F 21 is supplied to a decoding circuit (decoder) 22 and subjected to expansion processing corresponding to the compression method used in the compression / expansion circuit 9 in the recording / reproducing apparatus 1.

The video data output from the decoding circuit 22 is converted into an analog video signal by the D / A converter 23, and then a video video is displayed on the CRT 24. The operation section 26 is a section for changing an input changeover switch of the monitor 2, inputting an instruction for various settings, and inputting an instruction when the TV 2 also serves as a TV receiver. Each part of the monitor is controlled by the system controller 25 based on the instruction from the operation unit 26.

Next, the operation of the printer 3 will be described with reference to FIG. That is, among the data input to the 1394 I / F unit 31, data to be printed such as still image data classified by the data selector 32 for each data type is processed as follows. That is, the compressed data is subjected to decompression processing by the decoding circuit 33 and then subjected to image processing suitable for printing by the image processing circuit 34, so that storage and reading are controlled by the printer controller 38. Is formed as a print image in the memory 35. Then, the print image is sent to the printer head 36 and printed.

Driving such as head driving and paper feeding of the printer 3 is performed by a driver 37.
The operation control of the printer head 36 and the control of other parts are performed by a printer controller 38.
The printer operation unit 39 is for inputting instructions such as paper feed, reset ink check, and standby / start / stop of the printer operation. The printer controller 38 controls each unit according to the instruction input. .

When the data input to the 1394 I / F unit 31 is any command data for the printer 3, the data is transmitted from the data selector 32 to the printer controller 38 as a control command. Of the printer 3 corresponding to.

Since the printer 3 includes the decoder 33, it is set so as to receive the channel of the compressed video packet (the channel A in FIG. 2), and the channel of the compressed packet which is isochronously transferred on the bus is set to 13 channels.
The data is received from the 94 I / F 31.

Next, the operation of the printers 4 and 5 will be described with reference to FIG. That is, of the data input to the 1394 I / F unit 40, data to be printed such as still image data classified by the data selector 41 for each data type is output to the image processing circuit 42. Note that the printers 4 and 5 do not include a decoder such as the decoding circuit 33 in FIG. In the image processing circuit 42, image processing suitable for printing is performed, so that the image is formed as a print image in a memory 43 in which storage and readout are controlled by a printer controller 46. Then, the print image is sent to the printer head 44 and printed.

Driving of the printers 4 and 5 such as head driving and paper feeding is performed by a driver 45, and operation control of the driver 45 and the printer head 44 and control of other units are performed by a printer controller 46. . The printer operation unit 47 is for inputting instructions such as paper feeding, reset ink check, and standby / start / stop of the printer operation. The printer controller 46 controls each unit in response to the instruction input. .

If the data input to the 1394 I / F unit 40 is any command data for the printer 4 or 5, the data selector 41
Is transmitted to the printer controller 46 as a control command, and the printer controller 46 controls each part of the printers 4 and 5 corresponding to the control command.

Since the printers 4 and 5 are not provided with a decoder, they are set to receive the channel of the uncompressed video packet (channel B in FIG. 2), and the uncompressed video packet which is isochronously transferred on the bus is set. The channel of the packet is received from the 1394 I / F 40. The above is the description of the block diagrams 3 to 6.

By connecting the devices 1 to 5 shown in the block diagrams as described above with a 1394 serial bus as shown in FIG. 1, still image data can be transmitted from the recording / reproducing device 1 to the receiving node without passing through a PC. Can be transferred directly to At this time, the receiving node receives either the compressed or uncompressed still image data output from the recording / reproducing device 1. Thus, display and printing can be performed smoothly regardless of the presence or absence of the corresponding decoder in the receiving node. In addition, for a node having a decoder, the time required for still image transfer can be reduced.

Next, the operation in the first embodiment will be described with reference to a flowchart shown in FIG. 7, which will be described. In the print data transfer mode of the recording / reproducing apparatus 1, the user selects a still image desired to be printed in step S1. In selecting a still image, a desired one image is selected from a plurality of still image cuts recorded on a recording medium. When a moving image is handled by the recording / reproducing apparatus 1,
A desired one frame (or one field) image in a moving image may be designated, and the image formed by the image memory 15 or 17 may be handled as a print still image here.

Next, in step S2, the above-described step S1
The still image selected in step 1 is reproduced by the recording / reproducing system 10 to perform a reproduction process. As the first route of the reproduced compressed still image data, the compressed still image data is stored in the image memory 1.
Write to 7. In step S3, as the second route parallel to this, the same compressed still image data reproduced by the recording / reproduction system 10 is subjected to expansion processing by the compression / expansion circuit 9, and the data content is The same uncompressed still image data as the compressed still image data written to the image memory 17 is written to the other image memory 15.

Next, in step S4, the process shifts from the recording / reproducing device 1 to a transfer process to another node.
The compressed still image data is read from the image memory 15 under the control of the memory control unit 18 and the uncompressed still image data is read from the image memory 15 under the control of the memory control unit 16. Then, each data is given to the 1394 I / F section 20 via the data selector 19. Here, a band is secured for each data transfer, and the data is divided by the channel in the isochronous transfer allocated to each data and the transfer is started.

Each of the compressed and uncompressed data is isochronously transferred on the 1394 serial bus. Step S5
Then, the monitor 2 and the printer 3 receive the compressed data. That is, since these are completely equipped with a decoder, they receive the channel of the compressed data according to the setting of receiving the channel of the compressed data in advance. The uncompressed data is received by the printers 4 and 5. That is, the channel of the uncompressed data is received according to the setting for receiving the uncompressed channel due to the lack of the decoding function. In this manner, each of the compressed and uncompressed still image data is transferred to the target node, and the same still image data can be obtained by any of the nodes that have been received upon completion of the transfer.

Next, in step S6, when both the transfer of the compressed still image data and the transfer of the non-compressed still image data are completed with a time lag, the print data transfer mode is temporarily ended, and the process returns to accept the next command. The above is the description of the flowchart in FIG. The above is the description of the first embodiment.

<Second Embodiment> Next, a second embodiment will be described. In the first embodiment, the monitor 2 and the printers 3, 4, and 5 in FIG. 1 are targeted as nodes to which still image data is to be transferred. In this case, when transferring the still image data, the compressed data and the uncompressed data were mixed and transferred.

On the other hand, in the second embodiment, a case will be described in which all transfer destination nodes have a corresponding decoding function. That is, the description will be given using the network configuration of FIG. 1. In the second embodiment, the monitor 2 and the printers 3, 4, and 5 all have a decoding circuit (decoder) that can support the compression method in the recording and reproducing device 1. Is provided.

If all the nodes to which data is to be transferred are provided with decoders, the transfer of non-compressed data is the same as the method of transferring compressed data and non-compressed data of the same still image described in the first embodiment. No longer needed. That is, this second
In this embodiment, if the transfer of uncompressed data is performed, the transfer of the data becomes useless, and may cause an obstacle to other data transferred on the bus. Therefore, in the second embodiment, if all the nodes to which still image data is to be transferred have decoders in view of the network configuration, the transfer method of the uncompressed data in the transfer method shown in the first embodiment will be described. Do not transfer.

Next, a second embodiment will be described with reference to the drawings. In the second embodiment, the network configuration is as shown in FIG.
Since the recording / reproducing apparatus 1 and the monitor 2 are the same as those in the first embodiment, the detailed description is omitted here. It is also assumed that the printers 3, 4, and 5 are functionally the same printer. In particular, a common feature is that a function (decoder) capable of expanding video data compressed by the video compression method used in the recording / reproducing apparatus 1 is provided. That is, video data, particularly still image data, which has been compressed and transferred from the recording / reproducing apparatus 1, can be expanded and printed by a circuit in the printer.

FIG. 8 is a block diagram showing the configuration of the printers 3, 4, and 5. The configuration of each unit in FIG. 8 is the same as that described in FIG. The printers 3, 4, and 5 are connected as shown in the network configuration of FIG. That is, the printer 3 is connected to the monitor 2 and the printer 4, the printer 4 is connected to the printer 3, and the printer 5 is connected to the recording / reproducing apparatus 1 via one or two ports. Network.

Under such a configuration, in the mode shown in the first embodiment, the still image data as compressed and the uncompressed still image data can be transferred in parallel from the recording / reproducing apparatus 1. Even if there is, uncompressed data shall not be transferred. When transferring compressed still image data, transfer is performed using the isochronous transfer method, and for accompanying command data transfer, specify the transfer destination using the asynchronous transfer method and transfer. So that each is transferred on the bus.

Here, FIG. 9 shows a temporal state transition diagram when the still image compressed data is transferred from the recording / reproducing apparatus 1 to the bus in the second embodiment. A channel (channel) A in each cycle of FIG. 9 is a packet of compressed still image data that is being transferred by the isochronous transfer method. In this embodiment, the transfer of the uncompressed still image data is not performed.

[0149] One packet of channel A is incorporated into each cycle divided by the cycle start packet, and this is continued until the end of transfer. FIG.
Shows the flow of a time cycle including the cycle start packet and the isochronous transfer, and how the command data and the like are packet-transferred in an arbitrary cycle using the asynchronous transfer method as needed. I have. At this time, the command data is multiplexed and transferred within an arbitrary cycle as needed as an Async packet. In the second embodiment, such a transfer mode is assumed.

Next, a flowchart when the second embodiment is implemented is shown in FIG. 10 and will be described. This is an explanation as a flowchart of the overall embodiment, including the basic part of the present invention described in the first embodiment. In the print data transfer mode of the recording / reproducing apparatus 1, first, in step S11, a transfer destination node to which still image data is transferred is determined, and information such as presence / absence and type of a decoding function is confirmed for all transfer destination nodes. Here, the transfer destination node may be any node whose protocol matches that of the recording / reproducing apparatus 1, or all nodes limited to the node that desires to receive.

Then, the result of the decoder confirmation of the transfer destination node in step S11 is determined in step S12. Here, if all of the transfer-destination nodes have decoders, the flow proceeds to step S13. If one or more transfer-destination nodes do not have decoders, the flow proceeds to step S19. .

When all the transfer destination nodes have decoders, a mode is entered in which only the compressed still picture data is transferred. That is, in step S13, the user selects a still image desired to be printed. In selecting a still image, a desired one image is selected from a plurality of still image cuts recorded on a recording medium. When a moving image is handled by the recording / reproducing apparatus 1, a desired one frame (or one field) image in the moving image is designated, and an image formed in the image memory 17 is used as a print still image here. May be handled.

Next, in step S14, the above-described step S
The still image selected in 13 is reproduced by the recording / reproducing system 10 to perform a reproducing process, and the reproduced compressed still image data is written to the image memory 17 in a compressed state. In this case, the process of expanding the compressed still image data and writing it to the image memory 15 is not performed.

Next, in step S15, the processing shifts from the recording / reproducing device 1 to a transfer process to another node.
7, the compressed still image data is read out under the control of the memory control unit 18. Then, the compressed still image data is provided to the 1394 I / F unit 20 via the data selector 19.
Here, a band is reserved for data transfer, and transfer is started by the assigned channel in isochronous transfer.

The compressed still image data is isochronously transferred on the 1394 serial bus. In step S16, all the transfer destination nodes (monitor 2, printers 3, 4,
5) receives the compressed data. That is, since these are completely equipped with a decoder, they receive the channel of the compressed data according to the setting of receiving the channel of the compressed data in advance. Thus, the compressed still image data is transferred to all nodes.

Next, when the transfer of the compressed still image data is completed in step S17, it is confirmed in step S18 whether or not another image is to be printed. When printing is to be performed, the flow returns to step S13. When printing is not to be performed, the print data transfer mode is temporarily terminated with this, and a turn is made to accept the next command.

On the other hand, if the result of determination in step S12 is that there is a transfer destination node having no decoder, the mode is entered in which both compressed still image data and non-compressed still image data are transferred. In this case, step S19
The user selects a still image desired to be printed. In selecting a still image, a desired one image is selected from a plurality of still image cuts recorded on a recording medium. When a moving image is handled by the recording / reproducing apparatus 1, a desired one-frame (or one-field) image in the moving image is designated, and the image formed by the image memory 15 or 17 is stored in the stationary image for printing here. It may be treated as a picture.

Next, at step S20, the above-mentioned step S20 is executed.
The still image selected in 19 is reproduced by the recording / reproducing system 10 to perform reproduction processing, and the still image data as compressed is written to the image memory 17 as the first route of the reproduced compressed still image data. In step S21, the same compressed still image data reproduced by the recording / reproducing system 10 is subjected to expansion processing by the compression / expansion circuit 9 as a second route parallel to this, and the data content is Image memory 1
The same uncompressed still image data as the compressed still image written in 7 is written to the other image memory 15.

Next, in step S22, the processing shifts from the recording / reproducing device 1 to the transfer process to another node, and the image memory 1
7, the compressed still image data is read from the image memory 15 under the control of the memory control unit 16, and the uncompressed still image data is read from the image memory 15 under the control of the memory control unit 16.
Then, the data is provided to the 1394 I / F unit 20 via the data selector 19. Here, a band is secured for each data transfer, and the data is divided by the channel in the isochronous transfer allocated to each data and the transfer is started.

Each of the compressed and uncompressed data is isochronously transferred on the 1394 serial bus. Step S2
At 3, the node with the decoder receives the compressed data. In other words, the nodes receive the compressed data channel according to the fact that these nodes are completely equipped with the decoder and are set in advance to receive the compressed data channel.

[0161] Uncompressed data is received by a node without a decoder. That is, the channel of the uncompressed data is received according to the setting for receiving the uncompressed channel due to the lack of the decoding function. In this manner, each of the compressed and uncompressed still image data is transferred to the target node, and the same still image data can be obtained by any of the nodes that have been received upon completion of the transfer.

Next, when both the transfer of the compressed still image data and the transfer of the non-compressed still image data are completed with a time lag in step S24, it is confirmed in step S25 whether or not another image is to be printed. Return. When the printing is not performed, the print data transfer mode is temporarily terminated with this, and the process returns to accept the next command. The above is the description of the flowchart in FIG. The above is the description of the second embodiment.

The first embodiment and the second embodiment
In the embodiment, as a method of transferring the same video data in both compression and non-compression in the present invention, a description has been given by dealing with still images, but the gist of the present invention is that the content of the same data is compressed state, Since data transfer is performed in both the non-compressed state, AV data such as a moving image or other computer data may be used regardless of the type of data. Further, the device equipped with the present invention is not limited to the recording / reproducing device 1, but any device having data output means can be used instead. Further, if the apparatus is a recording / reproducing apparatus, a plurality of recording media serving as an output source of data in the apparatus may be provided.

Further, in the above embodiments, a bus called a 1394 serial bus has been described, but the present invention is not limited to this, and any bus using the DS-Link system can be similarly applied.

[0165]

As described above, according to the present invention,
A decoder is provided when there are a plurality of transfer destination nodes for transferring data having the same contents with respect to data transferred from the first node, for example, still image data for printing or screen display. It is possible to improve the transfer efficiency by transferring and receiving compressed data to a device, and to transfer and receive uncompressed data to a node having no decoder. Thus, data can be smoothly transferred to a plurality of nodes connected to the network and having different decoding functions. Further, in a network composed of a plurality of nodes, when all nodes that can receive transfer data from the first node have decoders that can support the compression method of the first node. By not transferring uncompressed data, the transfer efficiency can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a network to which the present invention is applied.

FIG. 2 is a state transition diagram showing a state of data transfer on a bus according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration example of a recording / reproducing apparatus for describing the present invention.

FIG. 4 is a block diagram showing one configuration example of a monitor for explaining the present invention.

FIG. 5 is a block diagram illustrating a configuration example of a printer according to a first embodiment for describing the present invention.

FIG. 6 is a block diagram illustrating a configuration example of another printer according to the first embodiment for describing the present invention.

FIG. 7 is a flowchart for explaining the first embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration example of a printer according to a second embodiment for describing the present invention.

FIG. 9 is a state transition diagram showing a state of data transfer on a bus according to the second embodiment of the present invention.

FIG. 10 is a flowchart for explaining a second embodiment of the present invention.

FIG. 11 is a diagram illustrating an example of a network configuration connected using a 1394 serial bus.

FIG. 12 is a diagram showing components of a 1394 serial bus.

FIG. 13 is a diagram showing an address map of a 1394 serial bus.

FIG. 14 is a sectional view of a 1394 serial bus cable.

FIG. 15 is a diagram for explaining a DS-Link coding scheme.

FIG. 16 is a diagram illustrating a topology setting for determining an ID of each node on a 1394 serial bus.

FIG. 17 is a diagram for explaining arbitration on a 1394 serial bus.

FIG. 18 is a diagram showing a temporal state transition of asynchronous transfer.

FIG. 19 is a diagram illustrating an example of an asynchronous transfer packet format.

FIG. 20 is a diagram illustrating a temporal state transition of isochronous transfer.

FIG. 21 is a diagram illustrating an example of a packet format for isochronous transfer.

FIG. 22 is an example of a bus cycle showing a state of a packet transferred on an actual bus in a 1394 serial bus.

FIG. 23 is a flowchart showing a flow from a bus reset to a determination of a node ID.

FIG. 24 is a flowchart showing a flow of parent-child relationship determination in a bus reset.

FIG. 25 is a flowchart showing a flow from the determination of a parent-child relationship in a bus reset to the determination of a node ID.

FIG. 26 is a flowchart for explaining arbitration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording / reproducing apparatus (1st node) 2 Monitor 3 Printer 4 Printer 5 Printer 9 Compression / expansion processing circuit 10 Recording / reproducing system 12 System controller 15 Image memory 17 Image memory 19 Data selector 22 Decoding circuit (decoder) 25 System controller 33 Decoding circuit (decoder) 38 Printer controller 46 Printer controller

Claims (22)

[Claims] 1. A data communication system for transferring data from a first node to another node via a serial bus using a DS-Link system, wherein the first node compresses the data in a predetermined manner. A data communication system having a configuration for compressing and transferring data by a method, and comprising means for transferring compressed data and means for transferring uncompressed data during data transfer. 2. The first node executes both transfer of compressed data and transfer of uncompressed data having the same data content within a cycle period, and repeats this in each cycle until the end of each transfer. The data communication system according to claim 1, wherein: 3. The data communication system according to claim 1, wherein the first node is a video recording / reproducing device. 4. The data communication system according to claim 1, wherein said another node is a printer. 5. The system according to claim 1, wherein the first node and the other node are directly connected by a serial bus using the DS-Link system.
A data communication system according to item 9. 6. The data communication system according to claim 1, wherein the serial bus using the DS-Link system is an IEEE 1394 serial bus. 7. A recording / reproducing apparatus as a first node,
What is claimed is: 1. A data communication system for transferring video data to another node via a serial bus using an S-Link system, wherein said recording / reproducing apparatus compresses and records video data according to a predetermined compression system during video recording. Has a configuration to record in the section,
At the time of transferring the video data, for the compressed video data read from the recording unit, there is provided a means for transferring the packet as it is compressed, and a means for decompressing and transferring the packet as uncompressed data. A data communication system wherein both the same compressed video packet transfer and the non-compressed video packet transfer are executed within a cycle period, and this is repeated in each cycle until the end of each transfer. 8. The data communication system according to claim 7, wherein said compressed video data and said non-compressed video data are transferred using isochronous transfer in an IEEE 1394 serial bus transfer system, and data allocation is performed. A data communication system characterized in that the type of data can be distinguished by distinguishing between compressed and uncompressed data, and each channel is multiplexed and transferred within one cycle. 9. The other node according to whether or not it has a decoder capable of decompressing the compressed data according to the predetermined compression method, either a channel for compressed data or a channel for uncompressed data. The data communication system according to claim 8, wherein data is received by selecting the data communication. 10. A means for judging whether all nodes that can be data transfer destinations have a decoder capable of decompressing compressed data according to the predetermined compression method, and all the transfer destination nodes have the decoder. 10. The data communication system according to claim 1, wherein only the compressed data is transferred when the data communication is performed. 11. A data communication method for transferring data from a first node to another node via a serial bus using the DS-Link system, wherein the compressed data having the same data content is transmitted. A data communication method characterized by performing both transfer and transfer of uncompressed data within a cycle period, and repeating this in each cycle until the end of each transfer. 12. The data communication method according to claim 11, wherein the transfer of the compressed data and the uncompressed data is performed by IEEE.
The transmission is performed using the isochronous transfer in the E1394 serial bus transfer method. At this time, the type of data can be discriminated by distinguishing the channel to which data is allocated by compression or non-compression, and each channel can be separated within one cycle. A data communication method characterized by multiplexing and transferring. 13. The compressed data or the non-compressed data according to whether the other node that can be a data transfer destination has a decoder that can decompress the compressed data by a corresponding compression method. 13. The data communication method according to claim 11, wherein the data communication method selects and receives the data. 14. It is determined whether or not all nodes that can be data transfer destinations have decoders that can decompress the compressed data by a corresponding compression method, and all the transfer destination nodes have the decoders. in case of,
14. The data communication method according to claim 11, wherein only the compressed data is transferred. 15. A compression means for compressing data by a predetermined compression method, and a decoding means for decoding data compressed by the compression means by a method corresponding to the predetermined compression method, are identical in data content. A data communication node comprising: data transfer means for performing both transfer of compressed data and transfer of uncompressed data within a cycle period, and repeating the transfer in each cycle until the end of each transfer. 16. A configuration in which video data is compressed by a predetermined compression method at the time of video recording and recorded in a recording unit. At the time of video data transfer, compressed video data read from the recording unit is compressed. Means for transferring the packet as it is, and means for transferring the packet as uncompressed data after decompression processing, so that the transfer of the compressed video packet and the transfer of the uncompressed video packet having the same data content are performed within the cycle period. A data communication node which executes both of them in each cycle until each transfer is completed. 17. The data communication node according to claim 16, wherein the transfer of the compressed video data and the non-compressed video data is performed using isochronous transfer in an IEEE 1394 serial bus transfer system, wherein the compressed video data and the uncompressed video data are transmitted. Data is allocated to an arbitrary channel, the uncompressed video data is allocated to an arbitrary channel different from the channel to which the compressed video data is allocated, and transferred, and each channel is multiplexed and transferred within one cycle. A data communication node, comprising: 18. A means for judging whether all nodes that can be data transfer destinations have decoders capable of decompressing compressed data according to the predetermined compression method, and the decoders are provided in all transfer destination nodes. The data communication node according to any one of claims 15 to 17, wherein only the compressed data is transferred when the data communication is performed. 19. Another data communication node for receiving data transferred from the data communication node according to claim 15, wherein the data compressed by the predetermined compression method can be expanded. A data communication node for selecting and receiving either the compressed data or the uncompressed data according to whether or not a decoder is provided. 20. When data is transferred from a first node to another node via a serial bus using the DS-Link system, the transfer of compressed data and the transfer of uncompressed data having the same data content are performed. In a cycle period, and repeating this in each cycle until the end of each transfer. 21. The recording medium according to claim 20, wherein in said procedure, said compressed data and said uncompressed data are transferred using isochronous transfer in an IEEE 1394 serial bus transfer method. A recording medium characterized in that the type of data can be distinguished by differentiating an assigned channel between compressed and uncompressed data, and that each channel is multiplexed and transferred within one cycle. 22. Determine whether all nodes that can be data transfer destinations have decoders that can decompress the compressed data by the corresponding compression method, and all the transfer destination nodes have the decoders. in case of,
22. The recording medium according to claim 20, further comprising a procedure of controlling so as to transfer only the compressed data.