JP2006050653A - Data communication apparatus, method, and system, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure data transmission and reception in terms of compression data to the utmost. <P>SOLUTION: In a transmission source 101 it is investigated before transmission of data whether a coding system of a transmission destination 102 is coincident with a coding system of the transmission source. If coincident, then compressed data is transmitted, and if not then the data is transmitted after it is decoded. Alternatively, if a decoding system of the transmission destination 102 can be changed in response to a program, in the transmission source 101 a decoding program is sent to the transmission destination 102 prior to the data transmission, and thereafter the compression data is transmitted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a data communication in which data communication is performed between devices connected to other electronic devices (hereinafter referred to as devices) using, for example, a data communication bus capable of communicating by mixing control signals and data. The present invention relates to an apparatus and method, a data communication system, and a storage medium.

  Among personal computer peripheral devices, hard disks and printers are most frequently used. These peripheral devices are general-purpose interfaces for small computers and are representative digital interfaces (hereinafter referred to as digital I / F) such as SCSI. The personal computers are connected to each other and data communication is performed.

  A recording / playback device such as a digital camera or a digital video camera is also one of peripheral devices used for image input to a personal computer (hereinafter referred to as a PC). In recent years, technology in the field of capturing still images and moving images shot with a digital camera or video camera to a PC and storing them on a hard disk or editing them on a PC and then printing them with a printer has been advancing. is increasing.

  When the captured image data is output from a PC to a printer or hard disk, data communication is performed via the SCSI or the like. In such a case, in order to send information having a large amount of data such as image data, such a digital I / F is required to have a high transfer data rate and versatility.

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

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

  A procedure for capturing an image captured by the digital camera 31 into the PC 32 and outputting the image from the PC 32 to the printer 33 will be described. When the image data stored in the memory 34 of the digital camera 31 is read, one of the read image data is decoded by the decoding circuit 35, and image processing for display by the image processing circuit 36 Is displayed on the EVF 38 via the D / A converter 37. On the other hand, for external output, the digital I / O unit 39 is transmitted through a cable to the digital I / O unit 40 of the PC 32.

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

  When printing an image, image data is transmitted from the SCSI interface board 48 in the PC 32 via a SCSI cable, received by the SCSI interface 49 on the printer 33 side, and formed as a print image in the memory 50. The printer head 51 and the driver 53 operate under the control of the controller 52, and print image data read from the memory 50 is printed.

  The above is the procedure until the conventional image data is taken into the PC or printed.

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

  In addition, methods for compressing video data are diversified. JPEG is known as a method for compressing still images, and MPEG is known as a method for compressing moving images. In addition, a home digital VTR (DVC) uses a unique compression method combining VLC and DCT. As described above, various compression methods are considered by classifying each device or each data type.

  However, the problems with the digital interface mentioned in the above conventional example include that the SCSI has a low transfer data rate, that the cable is thick for parallel communication, the type and number of peripheral devices to be connected, the connection method, etc. There are limitations and many inconveniences have been pointed out.

  Also, many common home PCs are provided with a connector for connecting a SCSI or other cable on the back of the PC, and the shape of the connector is large, making it difficult to insert and remove. When connecting a mobile or portable device such as a digital camera or a video camera, which is not normally stationary, it must be connected to the rear connector of the PC, which is very troublesome.

  In addition, many peripheral devices are usually connected to personal computers. In the future, the number of types of peripheral devices will increase, and by improving the I / F, many digital devices will not be limited to PC peripheral devices. It is expected that connected communication will be possible. While this is very convenient, depending on the device, communication with a very large amount of data will also occur frequently, which will congest the network and affect the communication between other devices in the network. It can also be brought about. For example, when the user wants to continue or quickly print an image, the data communication between the PC and printer affects the entire network or the host PC, etc. It is also possible that the image printing will not be successful and the image printing will not be performed normally or may be delayed. As described above, there are problems such as a load on the PC due to network congestion and data communication depending on the operation status of the PC.

  In addition, when multiple devices are connected to a network, due to differences in the data compression methods used by each device for data transfer, compressed data that cannot be decompressed may be transferred by mistake or decompressed at the transfer destination. There are also problems with transfer operation and efficiency, such as transfer with uncompressed data.

  The present invention has been made to solve the above-mentioned conventional problems, and is a general-purpose digital device that can be integrated and installed in each digital device, eliminating the problems of conventional digital I / F as much as possible. Uses I / F (for example, IEEE1394-1995 high performance serial bus) to realize data communication between devices when a PC, printer, other peripheral devices, digital camera, digital VTR recording / playback device, etc. are connected in a network configuration. It is another object of the present invention to realize so-called direct printing in which video data or the like is captured from a recording / reproducing apparatus to a PC and video data is directly transferred to a printer for printing.

  More specifically, based on information such as whether the transfer destination device has decoding means and the type and configuration of the decoding means provided, the encoded data that has been compressed as data to be transferred is transmitted. Alternatively, it is an object to perform data transfer according to the configuration of the transfer destination by transmitting data after decoding the encoded data or by selecting and transmitting the data.

  Furthermore, by transferring the program information for decoding data to the transfer destination device, even when the transfer destination device does not have a decoding means suitable for decoding the data, the encoded data to be transferred is decoded. Is intended to be possible on the destination device.

  In order to achieve the above object, the present invention comprises the following arrangement. That is, an encoding means for encoding data by a predetermined method, a first mode for transmitting data in an encoded state, and a second mode for transmitting data after decoding the encoded data And transmitting means for transmitting data to the communication destination node, and the encoding method by the encoding means is a first encoding method corresponding to the decoding means provided in the communication destination node. If this mode is not supported, data is transmitted in the second mode.

  Further, an encoding unit that encodes data by a predetermined method, a transmission unit that transmits program information including a decoding procedure for decoding data encoded by the encoding unit, and an encoding unit that encodes the data. Second transmission means for transmitting the received data.

  A data communication system comprising a first node and a second node, each having an encoding means, wherein the second node decodes the data encoded by the first node. If so, the first node transmits the data encoded by the encoding means to the second node, and the second node decodes the data encoded by the first node. If no means is provided, the first node decodes the encoded data and transmits the data to the second node.

  A first node comprising an encoding means and a storage means for storing program information for decoding data encoded by the encoding means; and a first node for decoding encoded data based on the program information. In the data communication system formed by connecting two nodes, when the second node does not have program information for decoding data encoded by the first node, the first node Transmits the program information stored in the storage unit together with the data encoded by the encoding unit to the second node, and the second node decodes the data encoded by the first node. The first node transmits the data encoded by the encoding means to the second node.

  A data communication method for transmitting data encoded by a predetermined method, wherein information indicating whether or not the node can decode the data encoded by the predetermined method is acquired from a communication destination node If the data can be decoded, the encoded data is transmitted as it is. If the data cannot be decoded, the encoded data is transmitted after being decoded.

  Also, a data communication method for transmitting data encoded by a predetermined method, the node having program information for decoding the data encoded by the predetermined method from a communication destination node If there is information that indicates whether it is present or not, the encoded data is transmitted as it is. If not, the encoded data and the encoded data are decoded. To send program information.

  In addition, the storage medium stores a data communication program that transmits data encoded by a predetermined method, and the program decodes data encoded by the predetermined method from a communication destination node. If the information indicating whether or not it can be obtained and can be decoded, the encoded data is transmitted as it is. If the information cannot be decoded, the encoded data is decoded and transmitted.

  A data communication method for transmitting data encoded by a predetermined method, a storage medium for storing a program, wherein the program is encoded from a communication destination node by the predetermined method. Obtains information indicating whether or not it has program information for decoding the encoded data, and if so, transmits the encoded data as it is, and if not, It includes a code for transmitting the encoded data and program information for decoding the encoded data.

  According to the present invention, when performing data transfer, the transfer source node selects and transfers encoded data or non-encoded data according to the decoding function of the transfer destination node. Will improve.

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

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

  For this reason, the chance that data transfer is performed with encoded data increases, and the time required for data transfer can be reduced and the capacity required for storing received data can be reduced.

[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, since an IEEE1394 serial bus is used for the digital I / F for connecting the devices, the IEEE1394 serial bus will be described in advance.

<Outline of IEEE 1394 technology>
With the advent of home digital VTRs and DVDs, it is necessary to support real-time and high-information data transfer such as video data and audio data. In order to transfer such video data and audio data in real time and transfer them to a personal computer (PC) or other digital devices, an interface capable of high-speed data transfer with the necessary transfer functions is required. The interface developed from such a viewpoint is IEEE1394-1995 (High Performance Serial Bus) (hereinafter referred to as 1394 serial bus).

  FIG. 7 shows an example of a network system configured using a 1394 serial bus. This system is equipped with devices A, B, C, D, E, F, G, and H. 1394 serial buses between AB, AC, BD, DE, CF, CG, and CH Connected with a twisted pair cable. The devices A to H are, for example, a PC, a digital VTR, a DVD, a digital camera, a hard disk, a monitor, and the like. As the connection method between the devices, the daisy chain method and the node branch method can be mixed, and a connection with a high degree of freedom is possible.

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

  In the system as shown in FIG. 7, when a device is deleted from the network or newly added, the bus is automatically reset, and the network configuration up to that point is reset, and then a new A reliable network. This function makes it possible to always set and recognize the network configuration at that time.

  The data transfer rate is 100/200/400 Mbps, and devices with higher transfer rates support lower transfer rates and are compatible. As data transfer mode, asynchronous data such as control signals (Asynchronous data: hereinafter referred to as Async data) is transferred. There is a transfer mode. This Async data and Iso data are mixed in each cycle (usually 125μS per cycle), following the transfer of the cycle start packet (CSP) indicating the start of the cycle, giving priority to the transfer of Iso data. Transferred.

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

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

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

  The hardware and firmware are the actual 1394 serial bus configuration. The application layer of the software part differs depending on the software used, and is a part that defines how data is put 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. 9 shows a diagram of the address space in the 1394 serial bus. Each device (node) connected to the 1394 serial bus must have a 64-bit address unique to each node. By storing this address in the ROM, it is possible to always recognize the node address of itself and the other party, and to perform communication specifying the other party.

  The addressing of the 1394 serial bus is based on the IEEE1212 standard, and the address setting uses the first 10 bits for specifying the bus number and the next 6 bits for specifying the node ID number. The remaining 48 bits are the address width given to the device, and each can be used as a unique address space. The last 28 bits are used as a unique data area for storing information such as identification of each device and specification of use conditions. The above is an overview of the 1394 serial bus technology. Next, a technical part that can be said to be a feature of the 1394 serial bus will be described in more detail.

<< Electrical Specifications of 1394 Serial Bus >>
FIG. 10 shows a cross-sectional view of a 1394 serial bus cable. In the 1394 serial bus, a power supply line is provided in the connection cable in addition to the two pairs of twisted pair signal lines. As a result, it is possible to supply power to devices that do not have a power supply or devices whose voltage has dropped due to a failure. The voltage of the power supply flowing in the power supply line is specified as 8 to 40V, and the current is specified as the maximum current DC1.5A.

<DS-Link encoding>
FIG. 11 is a diagram for explaining the DS-Link encoding method of the data transfer format employed in the 1394 serial bus.

  The 1394 serial bus employs a DS-Link (Data / Strobe Link) encoding method. This DS-Link encoding method is suitable for high-speed serial data communication, and its configuration requires two signal lines. Main data is sent to one of the twisted wires, and a strobe signal is sent to the other twisted wire. On the receiving side, the clock can be reproduced by taking the exclusive OR of the communicated data and the strobe.

  Advantages of using this DS-Link encoding method are that transfer efficiency is higher than other serial data transfer methods, the PLL circuit is unnecessary, the circuit scale of the controller LSI can be reduced, and the data to be transferred Since there is no need to send information indicating that the device is in an idle state when there is no power, the transceiver circuit of each device can be put into a sleep state, thereby reducing power consumption.

<Bus reset sequence>
In the 1394 serial bus, each connected device (node) is given a node ID and recognized as a network configuration. When there is a change in this network configuration, for example, when there is a change due to increase / decrease in the number of nodes due to node insertion / removal, power ON / OFF, etc., it is necessary to recognize a new network configuration. The node enters a mode to recognize a new network configuration by sending a bus reset signal on the bus. The change detection method at this time is performed by detecting a change in the bias voltage on the 1394 port board.

  When a bus reset signal is transmitted from a certain node, the physical layer of each node receives the bus reset signal, and simultaneously transmits the generation of the bus reset to the link layer and transmits the bus reset signal to the other nodes. After all nodes have finally detected the bus reset signal, the bus reset is activated. The bus reset is also activated by issuing a command directly to the physical layer by means of hardware detection due to cable insertion / removal or network abnormality as described above, and host control from the protocol. Further, when the bus reset is activated, the data transfer is temporarily interrupted, and the data transfer during this time is awaited and resumed under a new network configuration after the end. The above is the bus reset sequence.

《Node ID determination sequence》
After the bus reset, each node enters an operation of giving an ID to each node in order to construct a new network configuration. A general sequence from bus reset to node ID determination at this time will be described with reference to the flowcharts of FIGS. The flowchart of FIG. 19 shows a series of bus operations from when a bus reset occurs until a node ID is determined and data transfer can be performed.

  First, as step S101, the occurrence of a bus reset in the network is constantly monitored. If a bus reset occurs due to the power ON / OFF of the 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 the new network from the state where the network is reset. When the parent-child relationship is determined among all nodes as step S103, one route is determined as step S104. Until the parent-child relationship is determined among all the nodes, the parent-child relationship is declared in step S102, and the route is not determined.

  When the route is determined in step S104, a node ID setting operation for giving an ID to each node is performed in step S105. Node IDs are set in a predetermined node order, and the setting operation is repeated until IDs are given to all the nodes. When the IDs are finally set for all the nodes in step S106, a new network configuration is established. Is recognized in all the nodes, the data transfer between the nodes can be performed in step S107, and the data transfer is started.

  When the state of step S107 is entered, a mode for monitoring occurrence of a bus reset is entered again. When a bus reset occurs, the setting operation from step S101 to step S106 is repeated.

  The above is the description of the flowchart of FIG. 19, but the part from the bus reset to the route determination of the flowchart of FIG. 19 and the procedure from the route determination to the end of ID setting in more detail in the flowchart diagram, 20 and 21.

  First, the flowchart of FIG. 20 will be described. When a bus reset occurs as step S201, the network configuration is once reset. In step S201, the occurrence of a bus reset is constantly monitored. Next, in step S202, as a first step of re-recognizing the connection status of the reset network, a flag indicating that each device is a leaf (node) is set. In step S203, the number of ports that each device has is connected to other nodes. In accordance with the result of the number of ports in step S204, in order to start the declaration of the parent-child relationship, the number of undefined ports (parent-child relationship is not determined) is checked. Immediately after the bus reset, the number of ports = the number of undefined ports, but as the parent-child relationship is determined, the number of undefined ports detected in step S204 changes.

  First, immediately after a bus reset, only a leaf can declare a parent-child relationship. A leaf can be known by checking the number of ports in step S203. In step S205, the leaf declares “it is a child and the other party is a parent” to the node connected to itself, and ends the operation.

  A node that has a plurality of ports in step S203 and has been recognized as a branch immediately after the bus reset indicates that the number of undefined ports> 1 in step S204. Therefore, the process proceeds to step S206, where a branch flag is set, and in step S207. Wait to accept the “parent” in the parent-child relationship declaration from the leaf.

  The leaf declares the parent-child relationship, and the branch receiving it in step S207 checks the number of undefined ports as appropriate in step S204. If the number of undefined ports is 1, the branch is connected to the remaining port. It becomes possible to declare “I am a child” in step S205 to the node. From the second time, even if the number of undefined ports is confirmed in step S204, the branch that is 2 or more waits again in step S207 to accept the “parent” from the leaf or another branch.

  Eventually, if any one branch or exceptionally leaf (because it was able to declare a child but didn't work quickly) became zero as a result of the number of undefined ports in step S204, this is the whole network The only node for which the number of undefined ports has become zero (all determined as parent ports) is flagged as a route in step S208, and recognized as a route in step S209. Is made.

In this way, the process from the bus reset shown in FIG. 20 to the declaration of the parent-child relationship between all the nodes in the network is completed.
Next, the flowchart of FIG. 21 will be described. First, the flag information of each node such as leaf, branch, and root is set in the sequence up to FIG. 20, and based on this, classification is performed in step S301.

  As an operation for assigning an ID to each node, the ID can first be set from the leaf. IDs are set from a young number (node number = 0 to 0) in the order of leaf → branch → root.

  In step S302, the number N (N is a natural number) of leaves existing in the network is set. Thereafter, in step S303, each leaf requests the root to give an ID. In the case where there are a plurality of requests, the route performs arbitration (operation to adjust to one) in step S304, gives the ID number to one winning node in step S305, and notifies the losing node of the result of the failure. Do. The leaf whose ID acquisition has failed in step S306 issues an ID request again and repeats the same operation. In step S307, the ID information of the node is broadcast to all nodes from the leaf that has acquired the ID. When the one-node ID information is broadcast, the number of remaining leaves is reduced by one in step S308. Here, as step S309, when the number of remaining leaves is 1 or more, the process of the ID request in step S303 is repeated, and when all the leaves finally broadcast ID information, step S309 is N = 0. Then, the process proceeds to branch ID setting.

  The branch ID setting is performed in the same manner as 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 the root to give an ID. On the other hand, arbitration is performed in step S312, and the route is given from the next young number that has been given to the leaf in order from the winning branch. In step S313, the route notifies the ID information or the failure result to the branch that issued the request. In step S314, the branch that has failed in ID acquisition issues an ID request again and repeats the same operation. In step S315, the ID information of the node is broadcast to all the nodes from the branch that has acquired the ID. When the one-node ID information is broadcast, the number of remaining branches is reduced by one in step S316. Here, as step S317, when the number of remaining branches is 1 or more, the operation from the ID request in step S311 is repeated until all branches finally broadcast the ID information. When all branches acquire node IDs, M = 0 in step S317, and the branch ID acquisition mode ends.

  At this point, the only node that has not obtained ID information is the root, so the lowest number not given in step S318 is set as its own ID number, and the route ID information is broadcast in step S319. To do.

  Thus, as shown in FIG. 21, after the parent-child relationship is determined, the procedure until the IDs of all the nodes are set is completed.

  Next, as an example, operations in the actual network shown in FIG. 12 will be described with reference to FIG. In the explanation of FIG. 12, the nodes A and C are directly connected to the lower level of the (root) node B, the node D is directly connected to the lower level of the node C, and further to the lower level of the node D. A hierarchical structure in which node E and node F are directly connected. The procedure for determining the hierarchical structure, root node, and node ID will be described below.

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

  In FIG. 12, it is the node A that first declared the parent-child relationship after the bus reset. Basically, you can declare a parent-child relationship from a node (called a leaf) that has a connection to only one port of the node. This allows you to know that you have only one port connection, so that you recognize that you are at the edge of the network, and the parent-child relationship is determined from the node that performed the action earlier. In this way, the port on the side (Node A between A and B) that has declared the parent-child relationship is set as a child, and the port on the other side (Node B) is set as the parent. Thus, the node A-B is determined as a child-parent, the node E-D is determined as a child-parent, and the node F-D is determined as a child-parent.

  Going up one more level, among the nodes that have multiple connection ports (called branches), the parent-child relationship declarations are made higher in order from the node that received the parent-child relationship declaration from another node. In FIG. 12, the node D first determines the parent-child relationship between D-E and DF, and then declares the parent-child relationship for the node C. As a result, the node D-C is determined as a child-parent. ing.

  Receiving the declaration of the parent-child relationship from node D, node C declares the parent-child relationship to node B connected to the other port. As a result, the node C-B is determined as a child-parent.

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

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

  Once the root node is determined, the next mode is to determine each node ID. Here, all the nodes notify all other nodes of their determined node IDs (broadcast function). The self ID information includes its own node number, connected position information, the number of ports it has, the number of connected ports, the parent-child relationship information of each port, and the like. As a procedure for assigning node ID numbers, first, a node (leaf) connected to only one port can be started, and node numbers = 0, 1, 2,.

  The node having the node ID transmits information including the node number to each node by broadcasting. As a result, it is recognized that the ID number is “assigned”. When all the leaves have obtained their own node IDs, the next step is to branch and the node ID numbers that follow the leaves are assigned to each node. Similar to the leaf, node ID information is broadcast sequentially from the branch to which the node ID number is assigned, and finally the root node broadcasts self ID information. That is, the route always has the highest node ID number.

  As described above, assignment of node IDs for the entire hierarchical structure is completed, the network configuration is reconstructed, and bus initialization is completed.

"arbitration"
In the 1394 serial bus, arbitration of the bus use right is always performed prior to data transfer. The 1394 serial bus is a logical bus network so that each individually connected device relays the transferred signal to all the devices in the network. Arbitration is necessary to prevent this. As a result, only one node can be transferred at a certain time.

  As a diagram for explaining the arbitration, FIG. 13 (a) shows a bus use request in FIG. 13 (b), and a bus use permission diagram will be described below.

  When arbitration starts, one or more nodes each issue a bus usage right request to the parent node. Node C and node F in FIG. 13 (a) are nodes that have issued a bus use right request. Upon receiving this, the parent node (node A in FIG. 13) further issues (relays) a bus use right request toward the parent node. This request is finally delivered to the mediation route.

  The root node that has received the bus use request determines which node uses the bus. This arbitration work can be performed only by the root node, and the node that won the arbitration is given permission to use the bus. FIG. 13B is a diagram in which the use permission is given to the node C and the use of the node F is denied. A DP (data prefix) packet is sent to the node that lost the arbitration to notify that it was rejected. The rejected node bus use request is waited until the next arbitration.

  As described above, the node that has won the arbitration and obtained the bus use permission can subsequently start data transfer. Here, a series of arbitration flows will be described with reference to the flowchart of FIG.

  In order for a node to begin data transfer, the bus needs to be idle. In order to recognize that the previous data transfer has been completed and the bus is now empty, a predetermined idle time gap length (eg, subaction By passing the gap, each node determines that its transfer can start.

  In step S401, it is determined whether a predetermined gap length corresponding to data to be transferred such as Async data and Iso data has been obtained. As long as the predetermined gap length cannot be obtained, the bus use right required to start the transfer cannot be requested, so the process waits until the predetermined gap length is obtained.

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

  Next, in step S404, if one or more bus use requests in step S403 are received by the route, the route checks the number of nodes that have made use requests in step S405. If the selected value in step S405 is the number of nodes = 1 (one node that has issued a usage right request), the bus use permission immediately after that is given to that node. If the selection value in step S405 is the number of nodes> 1 (a plurality of nodes that have made use requests), the route performs an arbitration operation in step S406 to determine one node to be permitted to use. This arbitration work is fair and is configured such that only the same node does not get permission every time, and rights are given equally.

  In step S407, a selection is made to divide one node that has obtained use permission by arbitrating the route from the plurality of nodes that issued the use request in step S406 and another node that has lost. Here, for a single node that has been arbitrated and obtained use permission, or a node that has obtained use permission without arbitration from the selection value in step S405 without using the number of requested nodes = 1, the route goes to that node as step S408. In response, a permission signal is sent. The node having obtained the permission signal starts to transfer data (packet) to be transferred immediately after receiving the permission signal. In addition, a DP (data prefix) packet indicating an arbitration failure is sent from the route to the node that has lost the arbitration in step S406 and the bus use is not permitted, and the node that has received the packet performs forwarding again in step S409. In order to issue a bus use request, the process returns to step S401 and waits until a predetermined gap length is obtained.

Asynchronous transfer
Asynchronous transfer is asynchronous transfer. FIG. 14 shows a temporal transition state in asynchronous transfer. The first subaction gap in FIG. 14 indicates the idle state of the bus. When the idle time reaches a certain value, the node that desires to transfer determines that the bus can be used, and executes arbitration for acquiring the bus.

  When the bus use permission is obtained by arbitration, data transfer is executed in the packet format. After the data transfer, the receiving node sends back a response result ack (return code for acknowledgment) to the transferred data after a short gap called ack gap and transfers it by sending a response or sending a response packet. Is completed. The ack consists 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.

  Next, FIG. 15 shows an example of a packet format for asynchronous transfer. The packet has a header part in addition to the data part and error correction data CRC, and the header part has a target node ID, source node ID, transfer data length, various codes, etc. as shown in FIG. Is written and transferred. Asynchronous transfer is one-to-one communication from the self node to the partner node. The packet transferred from the transfer source node is distributed to each node in the network. However, since the address other than the address addressed to itself is ignored, only one destination node reads. The above is the description of asynchronous transfer.

<< Isochronous transfer >>
Isochronous transfer is synchronous transfer. This 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. Asynchronous transfer (asynchronous) is a one-to-one transfer, but this isochronous transfer is uniformly transferred from one node of the transfer source to all other nodes by the broadcast function.

  FIG. 16 is a diagram showing a temporal transition state in isochronous transfer. 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 has a role of indicating the start time of each cycle and adjusting the time of each node. The node that sends the cycle start packet is a node called the cycle master, and after the end of the transfer in the previous cycle, it passes the predetermined idle period (subaction gap), and then announces the start of this cycle. Send cycle start packet. The time interval at which this cycle start packet is transmitted is 125 μS.

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

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

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

  Each packet, which is divided into each channel, has a header part in addition to the data part and error correction data CRC. The header part has a transfer data length, channel NO, etc. as shown in FIG. Various codes, error correction header CRC, and the like are written and transferred. The above is the description of isochronous transfer.

《Bus cycle》
In the actual transfer on the 1394 serial bus, isochronous transfer and asynchronous transfer can be mixed. FIG. 18 shows a time transition state of the transfer state on the bus in which isochronous transfer and asynchronous transfer are mixed. Isochronous transfer is executed with priority over asynchronous transfer. The reason is that after a cycle start packet, isochronous transfer can be started with a gap length (isochronous gap) shorter than the gap length (subaction gap) of the idle period necessary for starting asynchronous transfer. . Therefore, isochronous transfer is executed with priority over asynchronous transfer.

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

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

  When the idle time reaches the subaction gap where asynchronous transfer is possible, it is determined that a node that wishes to perform asynchronous transfer can move to execution of arbitration.

  However, the period during which asynchronous transfer can be performed is when the subaction gap for starting asynchronous transfer is obtained between the end of isochronous transfer and the time to transfer the next cycle start packet (cycle synch) Limited to.

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

  However, if it is time to send the next cycle start packet during an asynchronous or synchronous transfer operation (cycle synch), do not forcibly suspend and wait for the idle period after the transfer is completed. Send cycle start packet for cycle. That is, when one cycle continues for 125 μS or more, it is assumed that the fractional cycle is shortened from the reference 125 μS. In this way, the isochronous cycle can be exceeded or shortened on the basis of 125 μS. However, isochronous transfer is always executed if necessary for every cycle in order to maintain real-time transfer, and asynchronous transfer may be passed to the next and subsequent cycles because the cycle time is shortened. This delay information is managed by the cycle master. The above is the description of the IEEE1394 serial bus.

<Direct print system using IEEE1394 serial bus>
From here, a system in which each device is connected with a 1394 serial bus cable as shown in FIG. 1 will be described. The bus configuration in FIG. 1 includes a recording / reproducing device 101, a printer device 102, and a personal computer (PC) 103 connected by a 1394 serial bus drawn by a solid line as nodes, and each device is a 1394 serial bus. Data transfer based on the specifications can be performed. Here, the recording / reproducing apparatus 101 is a digital camera, a camera-integrated digital VTR, or the like that records and reproduces moving images or still images. Direct video printing is possible by transferring the video data output from the recording / reproducing apparatus 101 directly to the printer 102. Further, the connection method of the 1394 serial bus is not limited to the connection as shown in FIG. 1, and it is possible to configure the bus by connecting between arbitrary devices. In addition to the devices shown in FIG. Alternatively, the data communication device may be connected. The network in FIG. 1 is an example of a group of devices, and the connected devices are any devices that can be configured with an external storage device such as a hard disk or a 1394 serial bus such as a CDR or DVD. Also good.

  With reference to the bus configuration as shown in FIG. 1, the operation of the present embodiment will be described with reference to FIG. In the recording / reproducing apparatus 101, 4 is an image pickup system, 5 is an A / D converter, 6 is a video signal processing circuit, 7 is a compression / expansion circuit that compresses and expands during recording by a predetermined algorithm, and 8 is a magnetic tape or the like. Recording / reproducing system including a solid-state memory and its recording / reproducing head, 9 is a system controller, 10 is an operation unit for inputting instructions, 11 is a D / A converter, 12 is an EVF as a display unit, and 13 is uncompressed Frame memory for storing video data to be transferred, 14 is a memory control unit for controlling reading of the memory 13, etc., 15 is a frame memory for storing compressed video data to be transferred, 16 is for controlling reading of the memory 15, etc. A memory control unit 17, a data selector 17, and an I / F unit 1394 serial bus.

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

  In the PC 103, 61 is a 1394 I / F unit mounted on the PC, 62 is a PCI bus, 63 is an MPU, 64 is a decoding circuit for decoding video data compressed by a predetermined algorithm, 65 is A display incorporating a D / A converter, 66 is an HDD, 67 is a memory, and 68 is an operation unit such as a keyboard and a mouse. Next, the operation of the block diagram 2 will be described in order.

<Operation of recording / reproducing apparatus>
First, at the time of recording by the recording / reproducing apparatus 101, an analog video signal photographed by the imaging system 4 is digitized by the A / D converter 5 and then subjected to video processing by the video signal processing circuit 6. One of the outputs of the video signal processing circuit 6 is converted back to an analog signal by the D / A converter 11 as a video during shooting and displayed by the EVF 12. The other outputs are compressed (encoded) by the compression circuit 7 with a predetermined algorithm and recorded on the recording medium by the recording / reproducing system 8. Here, the predetermined compression processing is typically a JPEG method for digital cameras, and a compression method based on DCT (Discrete Cosine Transform) and VLC (Variable Length Coding) as band compression methods for home digital VTRs. Other than that, the MPEG system is used.

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

  The frame memory 13 and the frame memory 15 are controlled to be written / read by the memory control units 14 and 16 respectively controlled by the system controller, and the read video data is output to the data selector 17. At this time, the outputs of the frame memories 13 and 15 are controlled so that either one is output to the data selector 17 at the same time.

  The system controller 9 controls the operation of each unit in the recording / reproducing apparatus 101. The system controller 9 outputs control command data for externally connected devices such as the printer 102 and the PC 103, and transfers the 1394 serial bus from the data selector 17. It is also possible to Async transfer commands to external devices. Various command data transferred from the printer 102 and the PC 103 are input from the data selector 17 to the system controller 9 and can be used to control each part of the recording / reproducing apparatus 101. Of these, command data indicating the presence or absence of the decoder, the type of decoder, and the like, which are Async transferred from the printer 102 and the PC 103, are input to the system controller 9 as a request command. After that, when transferring the video data from the recording / reproducing device 101 based on the command data, it is determined whether to transfer the compressed or uncompressed video data, and the command is sent to the memory control units 14 and 16 accordingly. Then, control is performed so that one suitable video data is read from the frame memory 13 or 15 and transferred.

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

  The video data and command data input to the data selector 17 are transferred over the cable by the 1394 I / F 18 based on the specifications of the 1394 serial bus. The printer 102 is the video data for printing, and the PC 103 is the video data to be imported to the PC. Receive. Command data is also Async transferred to the target node as appropriate. As for the data transfer method, mainly data such as moving images, still images, and audio are transferred as Iso data by the isochronous transfer method, and the command data is transferred as Async data by the asynchronous transfer method. However, among the data transferred as normal Iso data, it may be sent asynchronous transfer when it is convenient to transfer it as Async data depending on the transfer situation.

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

  The print data input to the image processing circuit 22 is subjected to image processing suitable for printing here, and is developed as a print image in the memory 23 controlled to be stored and read by the printer controller 26. This print image is sent to the printer head 24 and printed. Driving of the printer, such as head driving and paper feeding, is performed by a driver 25, and operation control of the driver 25 and printer head 24 and other parts are controlled by a printer controller 23.

  The printer operation unit 27 is used to input instructions such as paper feed, reset, ink check, and standby / start / stop of printer operation. Each unit is controlled by the printer controller 26 in accordance with the instruction input. The

  Next, when the data input to the 1394 I / F unit 19 is command data for the printer 102, it is transmitted as a control command from the data selector 20 to the printer controller 26, and each unit of the printer 102 corresponding to the information by the printer controller 26. Is controlled.

  In addition, the printer controller 26 can output information such as the type of decoder included in the decoding circuit 21 in the printer 102 or the presence / absence of the decoding circuit 21 and transfer the information to the recording / reproducing apparatus 101 as Async data.

  Here, with regard to the decoding circuit 21, as an example of a decoder provided in the printer, the JPEG method can be considered. Since JPEG decoding is possible in software, the decoding circuit 21 has the JPEG decoding program file stored in the ROM in the circuit, or the decoding program is transferred from another node. A configuration may be used in which processing is performed using software and the like and then decrypted. If image data compressed by the JPEG method is transferred from the recording / playback apparatus to the printer and decrypted in the printer, the transfer efficiency is higher than the transfer after converting to uncompressed data, and software Therefore, it is convenient to provide a decoder in the printer itself without any problem in terms of cost. The decoding circuit 21 may be configured to include a JPEG decoding circuit (board) as hardware decoding.

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

<Operation of personal computer>
Next, processing in the PC 103 will be described. Video data transferred from the recording / playback apparatus 101 to the 1394 I / F unit 61 of the PC is transferred to each unit in the PC 103 using the PCI bus 62 as a data mutual transmission bus. Various command data in the PC 103 are also transferred to each unit using the PCI bus.

  In the PC 103, processing is performed by the MPU 63 using the memory 67 in accordance with an instruction input from the operation unit 68 and an OS (operating system) or application software. When the transferred video data is recorded, it is recorded on the hard disk 66.

  As with the printer, the video data to be transferred was data transferred with compression or non-compression selected so that optimum transfer can be performed based on information such as the presence / absence of the decoder or the decoder type received in advance by the recording / playback apparatus 101. It is data. Therefore, even if the received video data is compressed data, the data can be decompressed by a decompression method of a predetermined algorithm possessed by the decoding circuit 64 included in the PC 103.

  When the video data is displayed on the display 65, if it is compressed video data, it is decoded by the decoding circuit 64, and if it is uncompressed video data, it is directly input to the display 65, and D Video is displayed after / A conversion.

  Various decoding circuits 64 provided in the PC 103 are, for example, an MPEG system decoder inserted into a slot as a board, or a hardware built in the main body, or an MPEG system, JPEG system, etc. The soft decoder is owned by a ROM or the like, and a command can be transferred to the recording / reproducing apparatus 101 by using the type and presence of these decoders as information.

  In this way, the transferred video data is taken into the PC 103 and recorded, edited, transferred from the PC to another device, and the like.

  The system of the present embodiment is configured as shown in FIG. 2, so that before the video data is transferred from the recording / reproducing apparatus 101 to the printer 102 or the PC 103, the decoder information is used as a command from the transfer destination printer 102 or the PC 103. By including Async transfer, the recording / playback device 101 selects to transfer the compressed video data when the transfer destination device can decode, and to transfer the uncompressed video data when it cannot decode can do.

<Video data transfer procedure>
Next, the operation of the recording / reproducing apparatus 101 at the time of transferring video data is shown in FIG. 4 as a flowchart. In the mode in which the recording / playback apparatus 101 transfers video data to another device connected via a 1394 serial bus, first, in step S1, data transfer is set for the transfer destination device based on the designation by the user. As a result, in step S2, the recording / reproducing apparatus 101 includes predetermined information for informing transfer and information for urging to transfer information such as the presence / absence of the decoder included in the transfer destination device and the type thereof. The command is Async transferred to the transfer destination device using the 1394 bus. In response to the command in step S2, predetermined transfer confirmation command data including decoder information is Async transferred from the transfer destination device to the recording / reproducing apparatus 101, and the recording / reproducing apparatus 101 receives it.

  In step S3, the system controller 9 of the recording / reproducing apparatus 101 determines whether the decoder information has been received. When the decoder information is received and the presence and type of the decoder can be determined, the process proceeds to step S4. When the decoder information is not included in the received command due to the reason that the decoder information cannot be transmitted to the command, or when the information that the decoder does not exist is included in the command, or the transfer destination device If the command Async transfer is not received even after a predetermined period of time due to a transfer error on the bus, delay of Async transfer, or the like, the process proceeds to step S6.

  Here, among the command data transferred from the transfer destination device to the recording / playback apparatus 101 that is the transfer source, the decoder information is transferred in the compressed state when the video data recorded after being compressed is transferred. Or data that is used to determine whether to transfer data after returning to uncompressed state. In other words, this data also has a role as request data indicating whether transfer of compressed data is desired or transfer of uncompressed data is desired from the destination device. Therefore, if the transfer destination device, for example, the PC 103 knows in advance information on the compression method used by the transfer source recording / playback apparatus 101, a response to the command sent from the recording / playback apparatus in step S2 is obtained. Rather than simply a response including decoder information in the PC 103, it can also be used as a request command for designating whether to transfer video data as compressed data or uncompressed data.

  Next, in step S4, if the decoder type determined from the received decoder information is a decoder that can support the compression method of a predetermined algorithm of video data used in the compression / decompression circuit 7 of the recording / reproducing apparatus 101, Since decoding within the transfer destination device is possible, in step S5, the setting with the decoder, that is, the output from the memory 15 at the time of transfer of the video data is performed in order to transfer the compressed video data to the 1394 bus with ISO. Control to transfer. When the type of decoder determined in step S4 is not compatible with the compression method in the recording / reproducing apparatus 101, and when decoder information is not received in step S3, that is, there is no decoder in the transfer destination device. If it is determined not to do so, in step S6, no decoder is set, that is, the decompression processing of the video data to be ISO-transferred in the recording / reproducing apparatus 101 is performed, and then the non-compressed video data is ISO-transferred onto the 1394 bus. When the video data is transferred, the output from the memory 13 is controlled to be transferred.

  After setting the output format at the time of video data transfer according to the transfer destination device in this way, in step S7, the user records the video data to be transferred on the recording medium for printing or PC capture. Select from the currently displayed video. The recording / reproducing apparatus 101 performs a reading operation of the selected video. After performing the video selection operation, in step S8, the user issues a transfer command for the desired video.

  Next, based on the settings in steps S5 and S6, depending on whether or not there is a decoder that can support the transfer destination device in step S9, if so, the compressed video data reproduced from the recording medium in step S10 is ISO transferred. Therefore, the system controller 9 and the memory control 16 control to output and transfer the video data read from the memory 15 in response to the transfer command in step S8. If not, in step S11, the system controller outputs and transfers the video data read from the memory 13 in response to the transfer command in step S8 in order to ISO transfer the uncompressed video data after being decompressed by the decompression circuit 7. 9 and memory control 14 control. Basically, the video data is transferred by the isochronous transfer method using the 1394 serial bus, but may be sent by the asynchronous transfer.

  When the transfer of the desired video data is completed in step S12, it is determined in step S13 whether the user wants to transfer other video data or not, and if another video is selected, the process returns to step S7 to return the video The selection is repeated, and when no other video is selected, the process proceeds to step S14. In step S14, it is determined whether to change the transfer destination device to continue the video data transfer mode. When changing the transfer destination to another device and transferring the video data, repeat from the transfer destination designation in step S1, step S14. When there is no need to change the transfer destination and continue the mode, this flow is terminated. At all times, the process returns to step S1 with the execution of the instructed video data transfer mode, and this flow is repeated.

  As described above, the recording / reproducing apparatus of the present embodiment acquires information indicating what the decoding procedure of the transmission destination is from the transmission destination that transmits the video data, and transmits the transmission destination from the acquired information. If encoding is performed according to the procedure corresponding to the decoding order included in the encoded video data, the encoded video data is transmitted. Otherwise, the encoded data is decoded and transmitted. As a result, data transmission / reception can be reliably performed regardless of the encoding procedure / decoding procedure provided by the device connected by communication. Furthermore, if the devices that communicate with each other have the same encoding / decoding procedure, the encoded data is transmitted / received, so that communication can be performed quickly and the memory capacity required for transmission / reception is also decoded. Compared to the case where data communication is performed using the data thus obtained.

[Second Embodiment]
Next, a second embodiment will be described.

<System configuration>
In the second embodiment, the recording / reproducing apparatus 201 and the printer 202 as shown in FIG. 5 are used as nodes, and the bus configuration is connected by a 1394 serial bus cable. At this time, direct printing in which video data from the recording / reproducing apparatus 201 is printed by the printer 202 is realized.

  A block diagram at this time is shown in FIG. The configuration of the block diagram 6 is basically a configuration in which the PC is removed from the configuration of the first embodiment shown in the block diagram 2 and the recording / reproducing apparatus and the 1394 I / F of the printer are connected by peer-to-peer connection. It is. The part different from the block diagram 2 is mainly a soft decoding program for decompressing data compressed by a video data compression method such as MPEG, JPEG, DV, etc. performed by the compression circuit 7 of the recording / reproducing apparatus 201. The decode program information to be formed is held in the ROM 74, and this program information is read from the ROM 74 based on the control of the system controller 9 and the read control unit 73 as necessary, and from the data selector 17 through the 1394 I / F unit 18. The point is to forward to the node.

  As a transfer form of the decoding program information, the transfer is mainly performed by the asynchronous transfer method, and in some cases, the ISO transfer is performed, and before the video data is transferred or in parallel with the transfer of the video data packet, it is mixed and transferred in the gap. . In FIG. 6, the recording / reproducing apparatus 201 does not have the memory 13 for transferring uncompressed data and the memory control unit 14 thereof.

  On the other hand, in order to decode the video data, the printer 202 can receive the above-described decoding program information from the recording / reproducing apparatus 201 before receiving the video data or in parallel with the video data, and can rewrite all or a part thereof. Store in the memory 71. The received compressed video data is decoded by the decoding processing circuit 72 using the decoding program information stored in the memory 72.

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

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

  The other circuit elements in the block diagram 6 and their operations are the same as those described in the first embodiment, and will not be described.

  When transferring the compressed print video data from the recording / reproducing apparatus 201 to the printer 202, first, prior to the transfer of the video data, a decoding program corresponding to the video data compression method used in the recording / reproducing apparatus 201 is stored in the ROM 74. Read out and Async transfer to the printer 202. The printer 202 stores the received decoding program in the memory 71 and uses it for decoding the compressed video data to be transferred. The recording / playback apparatus 201 uses one unified compression / decompression method for all video data to be recorded. However, the recording / playback device 201 may be in a recording state in which a plurality of compression methods are mixed for each video data amount or time.

  With such a configuration, even if the printer does not have decoder information, it is possible to transfer the compressed video data, so that the transfer efficiency is better than the transfer of the uncompressed video data. Next, the operation of the second embodiment will be described with reference to a flowchart shown in FIG.

<Data transfer procedure>
First, in step S21, the user is allowed to designate a transfer destination device. In this embodiment, the printer is designated. Transfer settings are made based on the instruction. Next, the user selects video data to be printed from videos recorded on the recording medium. In step S22, the recording / reproducing apparatus 201 performs a read operation of the selected video. When the video selection operation is performed, the user is instructed to transfer a desired video in step S23.

  In step S24, it is determined whether or not a decoding program necessary for decoding the video data for which the transfer command has been issued needs to be transferred to the transfer destination device, here, the printer 202. When it is necessary, that is, when it is determined that the printer has the necessary decoding processing circuit 72 and the like for decoding processing, and that it is possible to decode the compressed video data by transferring the decoding program In step S25, a necessary decoding program is read from the ROM 74 and transferred to the printer 202. The printer 202 stores the received decoding program information in the memory 71.

  On the other hand, if it is determined in step S24 that no transfer is necessary, that is, the transfer destination printer 202 has the necessary decode program information in advance, or the same decode program information has been transferred in the past and has already been transferred. When necessary decoding information is stored in the memory 71, the decoding program information is not transferred, and the process proceeds to video data transfer.

  Note that the information for determining whether or not the transfer of the decoding program information to the printer 202 is unnecessary is that the information is requested from the recording / reproducing apparatus 201 to the printer 202 in step S23. It can be obtained by responding information indicating what decoding program information it has.

  Subsequently, the compressed video data commanded to be transferred in step S26 is read from the recording medium, output from the memory 15, and transferred to the printer 202.

  Upon receiving the compressed video data, the printer 202 performs video data decoding processing based on the stored decoding program information, and starts video data printing processing. When the transfer of the decoding program is not completed for the Async transfer, the video data decoding process is started after the completion of the decoding program transfer.

  In step S27, when the transfer of the desired video data is completed, a predetermined process is performed at the end of the transfer. In step S28, it is determined whether another video data is selected to be transferred, and another video is selected. If so, return to step S22 and repeat from the video selection. When no other video is selected, this flow is terminated. Further, this flow is repeated from step S21 as needed in accordance with the instruction to execute the video data transfer mode.

  As described above, in the system according to the present embodiment, since the decoding program information of the decompression method corresponding to the video compression method by the recording / playback apparatus is provided from the recording / playback apparatus to the printer, the video data transferred between the devices Is always compressed data. This reduces the amount of data, eliminates the need for decompression processing prior to transfer, and allows data to be transferred quickly. In addition, the data receiving side requires very little memory for storing data compared to receiving uncompressed data.

[Third Embodiment]
Next, a third embodiment will be described. In the third embodiment, as in the second embodiment, the recording / reproducing apparatus 201 and the printer 202 as shown in FIG. 5 are used as nodes, and the bus configuration is peer-to-peer connected with a 1394 serial bus cable, and direct printing is performed. Implement in a possible configuration.

<System configuration>
FIG. 23 shows a block diagram for explaining the third embodiment. The configuration of the block diagram 23 is the same as that of the frame memory 13 used in the block diagram 2 in order to transfer uncompressed video data to the recording / reproducing apparatus 201 of the block diagram 6 used in the second embodiment. The memory control unit 14 is added.

  In the third embodiment, transfer of decoding program information from the ROM 74, transfer of compressed video data from the frame memory 15, and transfer of uncompressed video data from the frame memory 13 are performed by the decoder transferred from the printer 202. Whether the system controller 9 should transfer only the compressed video data or the compressed video data and the decoding program information based on the command data (decoder information) including presence / absence, type and configuration information, It is determined whether uncompressed video data should be transferred, and each unit is controlled to perform data transfer as necessary.

  More specifically, there is information for decoding the compression method used in the recording / reproducing apparatus 201 in a part or all of the memory 71 in the printer 202 based on the decoder information in the printer transferred in advance, and decoding of the compressed video data When it is determined that the processing is possible (a hardware decoding unit may be used), the system controller 9 controls the memory 15 via the memory control unit 16 and remains compressed in accordance with a user instruction. Read video data and start ISO transfer.

  Although it is currently impossible to decode compressed video data from the decoder information from the printer due to lack of a decoding program, the decoding processing circuit in the printer can be provided by giving the decoding program information to the memory 71 that is part of the decoding circuit system. 72 can be used, and when it is determined that the printer can decode, the ROM read control unit 73 is controlled, and necessary decode program information is transferred from the ROM 74 to the memory 71 via the memory control unit 16. Control is performed so that the compressed video data is read from the memory 15 and transferred.

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

  Each part of the block diagram 23 and its operation are the same as those described in the first embodiment or the second embodiment, and will not be described.

  With this configuration, video data that has been compressed as much as possible can be transferred, so transfer efficiency is better than transfer of uncompressed video data, and uncompressed video data can be transferred even if compressed video data cannot be transferred. So convenient.

  Next, the operation of the third embodiment will be described with reference to a flowchart shown in FIG. First, in step S31, when the user designates the transfer destination device as a printer, transfer setting is performed based on the instruction. As a result, the recording / reproducing apparatus 201 transfers to the printer 202 predetermined information that tells that transfer is to be performed and information such as the presence / absence, type, and configuration of the decoder included in the transfer destination device in step S32. Async transfer of the command including information for prompting using the 1394 bus. In response to the command in step S32, the printer 202 performs Async transfer of predetermined transfer confirmation command data including decoder information to the recording / reproducing apparatus 201.

  Here, the system controller 9 of the recording / reproducing apparatus 201 determines whether or not the reception of the decoder information has been confirmed in step S33. When the decoder information is received, the process proceeds to step S34, and the printer 202 has no decoder function. Or, if the decoder information is not received because the device cannot transmit the decoder information, or if the command including the decoding information is not returned, or the bus is not specified, the transfer error on the bus, the delay of Async transfer, etc. If the command Async transfer is not received after the period, the recording / reproducing apparatus 201 shifts to a mode in which only uncompressed video data is transferred, and the process proceeds to step S40.

  Next, in step S34, the decoder function of the printer is checked from the decoder information, and if it is determined that all the compression methods used in the recording / reproducing apparatus 201 can be supported, compression is performed by transferring a predetermined decoding program to step S35. If it is determined that the video data can be decoded, the decoding means provided in the printer 202 does not support the method of transferring the decoding program, and the decoder provided does not support, or the decoding is not possible. When it is impossible to decode the video data to be transferred because, for example, the above means itself does not exist, the process proceeds to step S40, and the mode is changed.

  Here, among the command data transferred from the printer 202 to the recording / reproducing device 201 that is the transfer source, the decoder information is transferred while being compressed when transferring the video data recorded after being compressed, Alternatively, it is data that can be used as a basis for determining whether to transfer data after returning to non-compression, or to transfer compressed data together with the decoding program, and also serves as request data regarding the transfer mode from the printer 202 It will be. If advance notification of predetermined information is made between the nodes, a compressed data transfer command related to direct video data transfer is used instead of the decoder information when the command data for transfer confirmation for step S32 is returned. It is also possible to use it as a request command that means a transfer command for uncompressed data and a decode program transfer command.

  Next, when the decoding means in the printer 202 can decode the compressed video data of any compression method applied by the recording / reproducing apparatus 201, the compressed video data can be transferred, so the compressed video data is transferred. As shown in FIG.

  In step S35, the video data selected by the user is selected from the video recorded on the recording medium, and the recording / reproducing apparatus 201 performs the reading operation. After performing the video selection operation, in step S36, the user is instructed to transfer a desired video. In step S37, the video data instructed to be transferred is reproduced from the recording medium for transfer in a compressed state, output from the frame memory 15, and ISO transferred to the printer. The printer performs video data decoding processing based on a predetermined operation procedure, and starts video data printing processing.

  When the transfer of the desired video data is completed in step S38, the selection for transferring the other video data is performed in step S39. When another video is selected, the process returns to step S35 and repeats from the video selection. If you do not select, end here.

  On the other hand, in the printer 202, when the compressed video data is transferred using this system but cannot be decoded due to the configuration of the printer 202, the video data to be printed is always transferred by transferring the uncompressed video data. It can be carried out. As a mode for transferring uncompressed video data at this time, the flow enters step S40 and subsequent steps.

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

  In step S43, when the transfer of the desired video data is completed, a selection is made to transfer other video data in step S44. When another video is selected, the flow returns to step S40 to repeat the video selection and repeat the other video. If no selection is made, the process ends here.

  Next, when it is possible to decode the compressed video data to be transferred by giving a predetermined decoding program to the decoder means included in the printer 202, the flow from step S45 is set as a mode for transferring the decoding program and the compressed video data. enter.

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

  In step S47, it is determined whether it is necessary to transfer a predetermined decoding program necessary for decoding the video data in the transfer destination printer 202 with respect to the video data for which the transfer command has been issued. Reads out a necessary decoding program from the ROM 74 at step S48 and transfers it to the printer 202 by Async (or ISO). The printer 202 stores the received decoding program information in the memory 71 and performs decoding processing together with the decoding processing circuit 72.

  Further, as step S47, when hardware or software decoding means is provided in advance, or when the same decoding program has been transferred in the past and decoding information required this time is already stored in the memory 71, etc. When it is determined that the transfer of the decoding program is not necessary, the transfer of the decoding program is not performed and the process proceeds to the transfer of the video data.

  Subsequently, the video data instructed to be transferred in step S49 is read from the recording medium and output from the memory 15 in a compressed state, and is ISO-transferred to the printer. In the printer, based on a predetermined operation procedure, the video data transferred using an existing or transferred decoding program is decoded, and the video data printing process is started.

  When the transfer of the desired video data is completed in step S50, a selection is made to transfer other video data in step S51. When another video is selected, the process returns to step S45 to repeat the video selection and repeat the other video. If not selected, this is the end of this.

  At all times, the process returns to step S31 with execution of the instructed video data transfer mode, and this flow is repeated.

  As described above, the system of the first embodiment and the system of the second embodiment can be combined. In this system, encoded data is transmitted and decoded to a device that receives the decoding program information and decodes the encoded data according to the decoding program information and a device that has a circuit that executes a decoding procedure of various methods. Unencoded data is transmitted to a device that does not have a function. For this reason, the time for data transmission is shortened, and the utilization efficiency of the storage area is increased.

  In this embodiment, the video data compressed and recorded on the recording medium is described. However, the video is not limited to the recorded video, but is compressed video that is video data input from the imaging apparatus and has not been recorded. Data may be used.

  The recording / reproducing apparatus in the embodiment mainly relates to video data of moving images and still images, and is conscious of a camera-integrated VTR and a digital camera. It may be a digital device such as an MD, CD, or PC, and the data handled is not limited to video data, and may be audio data or various file data.

[Other Embodiments]
Note that the present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), or a device (for example, a copier, a facsimile device, etc.) including a single device. You may apply to.

  Another object of the present invention is to supply a storage medium storing software program codes for implementing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. This can also be achieved by reading and executing the program code stored in. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

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

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. A case where part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.

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

It is the figure which showed an example of the network of 1st Embodiment. 1 is a block diagram of a recording / reproducing apparatus, a printer apparatus, and a PC to which a first embodiment is applied. FIG. 10 is a block diagram illustrating a configuration when a digital camera, a PC, and a printer are connected around a PC in a conventional example. 6 is a flowchart showing a flow of operations in the recording / reproducing apparatus according to the first embodiment of the present invention. It is the figure which showed an example of the network of the 2nd, 3rd embodiment of this invention. It is a block diagram of a recording / reproducing apparatus and a printer apparatus to which a second embodiment is applied. It is a figure which shows an example of the network structure connected using 1394 serial bus. It is a figure showing the component of 1394 serial bus. It is a figure which shows the address map of 1394 serial bus. It is sectional drawing of a 1394 serial bus cable. It is a figure for demonstrating a DS-Link encoding system. It is a figure for demonstrating the topology setting for determining ID of each node by 1394 serial bus. It is a figure for demonstrating the arbitration in a 1394 serial bus. It is a basic block diagram showing the time state transition of asynchronous transfer. It is a figure of an example of the format of the packet of asynchronous transfer. It is a basic block diagram showing temporal state transition of isochronous transfer. It is a figure of an example of the format of the packet of isochronous transfer. It is a figure of an example of the bus cycle which showed the mode of the packet transferred on the actual bus | bath by 1394 serial bus. It is a flowchart figure which shows the flow from a bus reset to determination of node ID. It is a flowchart figure which shows the flow of the parent-child relationship determination in a bus reset. It is a flowchart figure which shows the flow after the parent-child relationship determination in bus reset to node ID determination. It is a flowchart for demonstrating arbitration. It is a block diagram of a recording / reproducing apparatus and a printer apparatus to which a third embodiment is applied. It is a flowchart which shows operation | movement of 2nd Embodiment. It is a flowchart which shows operation | movement of 3rd Embodiment.

Claims (27)

Encoding means for encoding data in a predetermined manner;
The communication destination is either the first mode in which data is transmitted in an encoded state or the second mode in which data is transmitted in a communication mode in which data before encoding or data after encoding is mixed. Transmitting means capable of isochronous transfer and asynchronous transfer,
The data is transmitted in the first mode when the encoding method by the encoding unit is an encoding method corresponding to the decoding unit included in the communication destination node, and in the second mode otherwise. A data communication apparatus comprising: control means for controlling the transmission means.   The data communication apparatus according to claim 1, wherein the transmission unit is a unit that transmits the data by isochronous transfer.   The data communication apparatus according to claim 1, wherein the data is image data.   2. The data communication apparatus according to claim 1, wherein the control unit determines whether or not the communication destination node corresponds to an encoding method by the encoding unit by communication using isochronous transfer.   2. The data communication apparatus according to claim 1, wherein the transmission means is means for performing transmission conforming to the IEEE 1394 standard.   5. The control unit according to claim 4, wherein when there is no appropriate response due to communication by synchronous transfer, the control unit determines that the communication destination node is compatible with an encoding method by the encoding unit. The data communication apparatus according to 1.   The data communication apparatus according to claim 6, wherein the appropriate response is a response within a predetermined period.   The data communication apparatus according to claim 1, wherein the transmission unit transmits data in the second mode when a communication destination node does not include a decoding unit. From the communication destination node, the presence or absence of the decoding means provided in the node, and if there is a decoding means, further comprises receiving means for receiving information such as the configuration and compression method,
3. The data communication apparatus according to claim 1, wherein whether to transmit in the first mode or the second mode is based on information received by the receiving unit. Encoding means for encoding data in a predetermined manner;
First transmission means for transmitting program information including a decoding procedure for decoding data encoded by the encoding means;
A data communication apparatus comprising: a second transmission unit configured to transmit the data encoded by the encoding unit and capable of isochronous transfer and asynchronous transfer. A receiving unit that receives information indicating a configuration, a compression method, and the like of the decoding unit included in the node from the communication destination node;
The data communication apparatus according to claim 10, wherein the first transmission unit transmits program information based on information received by the reception unit. A third transmission means for decoding the encoded video data and transmitting the decoded video data;
When the communication destination node includes a decoding unit that decodes the data encoded by the encoding unit, the encoded data is transmitted by the second transmission unit,
If the communication destination node receives the program information and can decode the data encoded by the encoding means, the transmission means transmits the program information and the second transmission means transmits the encoded data. Send
11. The data communication apparatus according to claim 10, wherein when the communication destination node cannot decode the data encoded by the encoding unit, the third transmission unit transmits the data.   The data communication apparatus according to claim 1, further comprising an imaging unit that captures video data. A data communication system in which a first node having an encoding means and a second node are connected,
The first node includes encoding means for encoding data in a predetermined manner;
The second data is transmitted in either the first mode in which data is transmitted in an encoded state or the second mode in which data is transmitted in a communication mode in which data before encoding or data after encoding is mixed. Transmitting means capable of isochronous transfer and asynchronous transfer,
When the encoding method by the encoding means is an encoding method corresponding to the decoding means included in the second node, the data is transferred to the second mode in the first mode. And a control means for controlling the transmission means so as to transmit to the data communication system.   15. The data communication system according to claim 14, wherein the transmission means is means for transmitting the data by isochronous transfer.   The data communication system according to claim 14, wherein the data is image data.   15. The data communication system according to claim 14, wherein the control unit determines whether or not the communication destination node corresponds to an encoding method by the encoding unit by communication using isochronous transfer.   15. The data communication system according to claim 14, wherein the transmission means is means for performing transmission conforming to the IEEE 1394 standard.   The control means determines that the node of the communication destination corresponds to the encoding method by the encoding means when there is no appropriate response by communication by synchronous transfer. The data communication system described in 1.   The data communication system according to claim 19, wherein the appropriate response is a response within a predetermined period.   Before sending data to the second node, the first node inquires of the second node whether it has means for decoding the data encoded by the encoding means, and the second node 15. The data communication system according to claim 14, wherein the data communication system determines whether to transmit the data in an encoded state or to decode and transmit the data based on a response from the node. A first node comprising encoding means and storage means for storing program information for decoding data encoded by the encoding means; and a second node for decoding encoded data based on the program information A data communication system formed by connecting nodes,
The first node includes encoding means for encoding data in a predetermined manner;
The second data is transmitted in either the first mode in which data is transmitted in an encoded state or the second mode in which data is transmitted in a communication mode in which data before encoding or data after encoding is mixed. Transmitting means capable of isochronous transfer and asynchronous transfer,
When the encoding method by the encoding means is an encoding method corresponding to the decoding means included in the second node, the data is transferred to the second mode in the first mode. And a control means for controlling the transmission means so as to transmit to the data communication system.   Does the first node have forward gram information for decoding the data encoded by the encoding means to the second node before transmitting the data to the second node? 23. The data communication system according to claim 22, wherein whether to transmit the program information together with data is determined based on an inquiry and a response from the second node. The first node further comprises imaging means for taking an image,
The data communication system according to any one of claims 22 to 23, wherein the second node further includes output means for printing out the received data. A data communication method for transmitting data encoded by a predetermined method,
A first transmission step of transmitting program information including a decoding procedure for decoding encoded data;
A data communication method comprising: a second transmission step of transmitting encoded data and capable of isochronous transfer and asynchronous transfer. A storage medium for storing a data communication program for transmitting data encoded by a predetermined method,
The program includes a first transmission step code for transmitting program information including a decoding procedure for decoding encoded data;
A storage medium comprising: a second transmission step code capable of isochronous transfer and asynchronous transfer for transmitting encoded data. A storage medium for storing a data communication program for transmitting data encoded by a predetermined method,
The program acquires information indicating whether or not the node has program information for decoding the data encoded by the predetermined method from the communication destination node. The encoded data is transmitted as it is, and when it does not have, the encoded data and the code for transmitting the program information for decoding the encoded data are included. Storage medium.

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