JP4609693B2 - Transmission device, data transmission method, and data transmission program - Google Patents

Description

The present invention is the transmitting apparatus, relates to a data transmission method and data transmission program, for example, IEEE between (The Institute of Electrical and Electronics Engineers ) 1394 system each device connected by a bus line, stream of content data or the like It is suitable for application when data is transmitted.

  Conventionally, AV equipment capable of mutually transmitting data via an IEEE 1394 serial data bus (hereinafter also simply referred to as a bus) has been developed. When performing data transmission via such a bus, the isochronous transfer mode used for real-time transmission of relatively large amounts of video data, audio data, etc., still images, text data, control commands, etc. Asynchronous transfer modes are used for reliable transmission, and a dedicated band is used for transmission for each mode.

  FIG. 23 shows a connection example using the IEEE 1394 bus, and a transmission device (source device) a that transmits data, a reception device (sink device) b that receives data from the transmission device a, A controller c that controls data transmission between the transmission device a and the reception device b is connected to an IEEE 1394 bus d.

  For example, when data is transmitted from the transmission device a to the reception device b, the controller c secures an isochronous transfer channel on the bus d, and the transmission device a and the reception device b can transmit data on the channel. Establish a connection between As a result, data transmission from the transmission device a to the reception device b becomes possible. Note that the transmitting device a or the receiving device b may also function as the controller c.

  Further, when performing data transmission between the transmission device a and the reception device b in this way, for example, a transmission method using a control command called an AV / C command (AV / C Command Transaction Set) is applied. (For example, refer nonpatent literature 1).

  By the way, when data having a predetermined format, for example, is transmitted from the transmission device a to the reception device b, the reception device b executes processing corresponding to the format. Therefore, when the format of data transmitted from the transmission device a to the reception device b changes in the middle, the reception device b needs to switch to a state for accepting data of the changed format.

  FIG. 24 shows a case where the format of the content data changes during transmission of the content data representing music from the disc playback device e corresponding to the transmission device a to the amplifier device f corresponding to the reception device b. It is the figure which showed an example. In this case, content data A and content data B having a format different from that of the content data A are recorded on an optical disc (not shown) played by the disc playback device e.

  When the disc playback device e finishes playback of the content data A recorded on the optical disc and starts playback of the content data B (timing ta), the amplifier device f sets the internal circuits and the like accordingly. Is changed to change to a state for accepting the content data B from a state where the content data A is accepted.

  Then, when the amplifier device f switches to a state for accepting the content data B (timing tb), the amplifier device f starts accepting the content data B sequentially transmitted from the disc reproducing device e and starts processing for this. Music based on the content data B is emitted from the speaker.

  Accordingly, since the amplifier device f cannot accept the head portion of the content data B transmitted from the disc playback device e from the timing ta to the timing tb, the amplifier device f emits music corresponding to the head portion. Can not be done, and it causes a so-called music break.

  The problem that the music is interrupted in this way appears particularly conspicuously when the rate control (flow control) process is executed between the disk reproducing device e and the amplifier device f.

  Here, the rate control process is a process of adjusting the output rate of the content data sent from the disc playback device e in accordance with the rate at which the amplifier device f processes the content data, as shown in FIG.

  In this case, a buffer memory m for temporarily storing content data is provided for the amplifier device f. The amplifier device f transmits rate control data to the disc playback device e so that the amount of data stored in the buffer memory m is substantially constant, and the disc playback device e outputs content data in accordance with the rate control data. Adjust the rate.

  In the amplifier device f having this configuration, for example, once the content data A is stored in the buffer memory m, the content data having a format different from that of the content data A until the content data A is completely output from the buffer memory m. B cannot be stored.

  Therefore, in the amplifier device f, when switching from the state in which the content data A is received to the state in which the content data B is received, not only the setting of the internal circuit and the like is switched, but also the content data temporarily stored in the buffer memory m An output process for outputting all A must also be executed. As a result, the amplifier device f has a problem in that the time during which the content data B cannot be received becomes longer due to the execution of the output process, and thus the music is severely cut off.

A method for solving such a problem has already been proposed (see Patent Document 1). For example, as shown in FIG. 26, the disc playback apparatus to which this technique is applied is for receiving the content data B from the amplifier device before starting the playback of the content data B after the playback of the content data A is completed. Polling processing (step S11x,...) For confirming whether or not the state has been switched to is repeatedly executed. When the disc reproducing apparatus receives a notification signal (step S14x) notifying that the state has been changed to the state for accepting the content data B from the amplifier apparatus, the disk reproducing apparatus starts reproducing the content data B and sends it to the amplifier apparatus. It is made to send out. By doing in this way, it can avoid that the music based on the content data B cuts off in the amplifier apparatus side.
1394 Trade Association, “TA Document 2001002 AV / C Stream Format Information Specification 1.0”, May / 24/2002 JP 2003-110563 A

  By the way, if the amplifier device is a model that does not support the format of the content data B, this amplifier device cannot be switched to a state in which the content data B is accepted, and therefore the polling process is repeatedly executed by the disk playback device. However, the notification signal notifying that the content data B has been switched to the state of accepting is not transmitted.

  However, the disc reproducing apparatus to which such a conventional method is applied performs a predetermined polling process in expectation of receiving the notification signal from the amplifier apparatus regardless of whether the notification signal can be received from the amplifier apparatus. There is a problem that it is difficult to say that the processing efficiency is good because it is executed for a period of time.

The present invention has been made in view of the above, the conventional transmission device capable of improving the remarkably and performance than is intended to provide a data transmission method and data transmission program.

In order to solve such a problem, in the transmission device of the present invention, whether or not the reception device that can communicate via a communication path established based on a predetermined communication method is compatible with the first format, And first confirmation means for executing first confirmation processing for confirming whether or not a plug for receiving data in the first format can be configured, and for the receiving apparatus in the first format. A second confirmation unit that executes a second confirmation process for confirming whether or not the state has been changed to an acceptance state for accepting data, and that the second confirmation process has recognized that the receiving apparatus has transitioned to the acceptance state. , inspection for detecting that a transmission means for transmitting data composed of the first format to the receiving device, the data transmitted by the transmitting means changes from the second format into the first format Means, a control means is provided, the first check means, and whether or not corresponding to the first format, whether transient may constitute a plug for receiving data to be in a first format at a time A command for confirming to the receiving device, a response to the command is received from the receiving device, and based on the response, whether the receiving device is compatible with the first format and the first The process for confirming whether or not a plug for receiving data in the format of the above can be configured is executed as the first confirmation process, and the control means receives the data transmitted by the detection means from the second format. Upon detecting the change to the first format, after the transmission of the data in the second format ends, the invalidity in the second format The transmission means over data is transmitted a predetermined time, it controls the first check means to perform a first verification process during the transmission of invalid data made in the second format, by the first verification process After recognizing that the receiving device is compatible with the first format and can constitute a plug for receiving data in the first format, after the transmission of invalid data in the second format is completed, Before transmitting the data in the first format, the invalidation data in the first format is transmitted by the transmission unit, and the second confirmation unit is controlled to start the second confirmation process. Recognizing that the receiving apparatus does not support the first format or cannot form a plug for receiving data in the first format by the confirmation process 1 Then, the second confirmation unit is controlled to immediately stop the second confirmation process and the transmission of invalid data in the first format .

Furthermore, in the data transmission method of the present invention, data to be transmitted to a receiving apparatus that can communicate via a communication path established based on a predetermined communication method changes from the second format to the first format. When detecting that the data transmitted in the detection step is changed from the second format to the first format, after the transmission of the data in the second format is completed, the second The invalid data in the format is transmitted to the receiving device for a predetermined time, and during the transmission of the invalid data in the second format, whether or not the receiving device supports the first format, and first confirmation scan executing the first confirmation process for confirming whether or not may constitute a plug for receiving data to be in a first format And-up, when received by the first verification processing unit recognizes that it is possible to configure the plug for receiving data to be in a first format and correspond to a first format, the second format After the transmission of the invalid data to be completed and before the data having the first format is transmitted, the invalid data having the first format is transmitted by the transmission unit, and the receiving apparatus is configured to use the first format. The second confirmation process for confirming whether or not a transition to an acceptance state for accepting data is started is started, and the reception apparatus does not support the first format by the first confirmation process or in the first format. comes to recognize that not constitute a state for receiving data, immediately sends the invalid data composed of second confirmation process and the first format A second verification step to cancel, when received by the second confirmation processing apparatus recognizes that a transition into the receiving state, and a transmission step of transmitting data to be in a first format to a receiving device provided, first In the confirmation step, a command for confirming at a time whether or not it is compatible with the first format and whether or not a plug for receiving data in the first format can be configured is transmitted to the receiving device. A plug for receiving a response to the command from the receiving device, receiving the data in the first format based on the response, whether the receiving device is compatible with the first format, and The process of confirming whether or not it can be configured is executed as the first confirmation process.

Furthermore, in the data transmission program according to the present invention, the communication path established based on the predetermined communication system is transmitted to the transmission apparatus that transmits data to the receiving apparatus via the communication path established based on the predetermined communication system. A detecting step for detecting that data to be transmitted to a receiving apparatus capable of communicating via the first format changes from the second format to the first format, and the data to be transmitted in the detecting step is changed from the second format to the first format. When the change to the format is detected, after the transmission of the data in the second format is completed, the invalid data in the second format is transmitted to the receiving device for a predetermined time, and the second format is used. during the transmission of invalid data, with respect to the receiving apparatus, whether or not corresponding to the first format, and the first format A first confirmation step, the reception device by the first verification process corresponds to the first format to perform first confirmation process for confirming whether or not may constitute a plug for receiving data composed of If it is recognized that a plug for receiving data in the first format can be configured, the data in the first format is transmitted after the transmission of invalid data in the second format is completed. Before, the invalid data having the first format is transmitted by the transmitting means, and the receiving device confirms whether or not the receiving apparatus has transitioned to the acceptance state for accepting the data having the first format. The confirmation process is started, and the reception apparatus receives data that does not correspond to the first format or is in the first format by the first confirmation process. It recognizes that it can not constitute a state immediately a second confirmation step to stop the transmission of the invalid data composed of second confirmation process and the first format, receiving the second check processing apparatus to the receiving state When the transition is recognized, a transmission step of transmitting data in the first format to the receiving device is executed. In the first confirmation step, whether or not the first format is supported and whether or not the first format is supported. A command for confirming whether or not a plug for receiving the data can be configured at a time is transmitted to the receiving device, receives a response to the command from the receiving device, and based on the response, Whether or not the receiving apparatus supports the first format, and can a plug for receiving data in the first format be configured? The process of confirming whether or not is executed as the first confirmation process.

In this way, before executing the second confirmation process for confirming to the receiving device whether or not the state has changed to the acceptance state, whether or not the receiving device is compatible with the first format in the first place, A first confirmation process for confirming whether or not a plug for receiving data in one format can be configured is executed, and the receiving apparatus does not support the first format by the first confirmation process. Alternatively, when it is confirmed that a plug for receiving data in the first format cannot be configured, the second confirmation process is stopped.

According to the present invention, the transmitting device cannot transition to a receiving device that does not correspond to the first format or cannot form a plug for receiving data in the first format, that is, an accepting state. It is possible to avoid unnecessary execution of the second confirmation process for confirming whether or not the reception apparatus has transitioned to the acceptance state, and as a result, the processing efficiency is significantly improved as compared with the conventional apparatus. Can be made.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Content Data Transmission System In FIG. 1, SYS 1 indicates a content data transmission system as a whole, and is configured by connecting a disc playback device 1, a control device 2, and an amplifier device 3 via an IEEE 1394 bus 9. Has been. The control device 2 has a function of controlling data transmission between the disk reproducing device 1 and the amplifier device 3.

  The disc playback device 1 plays back content data representing music from an optical disc (hereinafter also referred to as audio data), and transmits the played back audio data as stream data to the amplifier device 3 via the bus 9. . The amplifier device 3 receives audio data transmitted as stream data from the disc playback device 1 and executes predetermined processing on the audio data to obtain an analog audio signal, and music based on the audio signal is transmitted to the speakers 3d and 3e. Output from.

  Each of the disk reproducing device 1, the control device 2, and the amplifier device 3 is a device provided with an IEEE1394 bus connection terminal, and has a function capable of being controlled by an AV / C command. The control device 2 is a device (controller) that performs transmission control on the bus 9. Another device (not shown) connected to the bus 9 may be configured to perform transmission control on the bus 9, and the disk reproducing device 1 or the amplifier device 3 may have a function as a controller.

  The disk playback device 1, the control device 2, and the amplifier device 3 have a subunit that executes processing for realizing each function, a bus 9 and an internal subunit when viewed in terms of functions defined by AV / C commands. And a plug unit for inputting / outputting data between them. That is, the disc playback apparatus 1 includes a control unit 1a that executes a control function and a disc subunit 1b that performs playback from an optical disc under the control of the control unit 1a. The control device 2 includes a control unit 2 a that executes transmission control on the bus 9. The amplifier device 3 includes a control unit 3a that executes a control function, and an audio subunit 3b that performs signal processing of the audio signal and output processing thereof. Speaker devices 3d and 3e are connected to the audio subunit 3b. Further, the disc reproducing device 1, the control device 2, and the amplifier device 3 are each provided with plug portions 1c, 2b, and 3c. Each plug portion 1c, 2b, 3c is configured so that a plurality of plugs are mounted and can be connected to a plurality of channels on the bus 9.

  FIG. 2 shows an example of the internal configuration of the disc playback apparatus 1. The disc playback device 1 here is a device that plays back audio data recorded on the optical disc 101. As the optical disc 101 that can be played back by the disc playback apparatus 1, a DVD (Digital Video Disc or Digital Versatile Disc) or the like can be applied in addition to a CD (Compact Disc).

  The disc reproducing apparatus 1 optically reads a signal representing audio data recorded on the inserted optical disc 101 via the optical pickup 102, and supplies the read signal to the signal processing unit 103 for processing. To obtain audio data. In the disc playback apparatus 1, the audio data is converted into an analog audio signal by the digital / analog converter 104 and then output to an external audio device via the analog output terminal 105. Audio data before being converted by the digital / analog converter 104 is also output from the digital output terminal 106. Also, audio data reproduced from the optical disc 101 can be sent to the bus 9 via the IEEE 1394 bus interface unit 109.

  Playback operations in the disk playback device 1 and data transmission via the bus 9 are executed under the control of a central control unit (CPU) 110. The CPU 110 is connected to a memory 111 that stores data necessary for control.

  FIG. 3 shows an example of the internal configuration of the amplifier device 3. The amplifier device 3 includes an input terminal group 301 to which audio data and audio signals are supplied from an external audio device, and any audio data or audio data in the audio data or audio signal obtained through the input terminal group 301 An audio signal is selected by the input selection unit 302. When, for example, audio data is selected by the input selection unit 302, the signal processing unit 303 performs necessary signal processing on the selected audio data. In this signal processing, signal characteristic correction, multi-channel processing, and the like are performed using, for example, a digital processing circuit called a DSP (Digital Signal Processor). When an analog audio signal is selected by the input selection unit 302, the selected audio signal is converted from analog to digital in the signal processing unit 303, and then the above-described signal processing is performed on the obtained audio data. It is made to run.

  The signal processing unit 303 supplies the audio data after the signal processing to the digital / analog converter 304. The digital / analog converter 304 converts the supplied audio data into an audio signal, supplies the converted audio signal to the power amplifier unit 305, and amplifies it to an output capable of driving the speakers 3d and 3e. The output of the power amplifier unit 305 is supplied to the speakers 3d and 3e connected via the speaker terminals 306 and 307.

  The amplifier device 3 according to the present embodiment includes an IEEE1394 bus interface unit 308. When the bus interface unit 308 receives the audio data transmitted from the disc playback apparatus 1 via the bus 9, the bus interface unit 308 can supply the received audio data to the signal processing unit 303 via the input selection unit 302. ing.

  Signal processing operations in the amplifier device 3 and reception operations via the bus 9 are executed under the control of a central control unit (CPU) 309. The CPU 309 is connected to a memory 310 that stores data necessary for control.

  Next, a mechanism for transmitting data on the IEEE 1394 bus 9 will be described. FIG. 4 is a diagram showing a cycle structure of data transmission of devices connected by IEEE1394. In IEEE 1394, data is divided into packets and transmitted in a time division manner with a cycle of 125 μS as a reference. This cycle is generated by a cycle start signal supplied from a node having a cycle master function (any device connected to the bus). The isochronous packet secures a band (which is a unit of time but called a band) necessary for transmission from the beginning of every cycle. For this reason, in isochronous transmission, transmission of data within a certain time is guaranteed. However, if a transmission error occurs, there is no protection mechanism and data is lost. Asynchronous transmission in which the node that secured the bus as a result of arbitration sends out asynchronous packets during the time not used for isochronous transmission in each cycle ensures transmission by using acknowledge and retry. The transmission timing is not constant.

  In order for a node (device) connected to the network to perform isochronous transmission, the node must support the isochronous function. Also, at least one of the nodes connected to the IEEE 1394 serial bus must have a cycle master function. Furthermore, at least one of the nodes connected to the IEEE 1394 serial bus must have the function of an isochronous resource manager.

  FIG. 5 is a diagram showing the relationship among plugs, plug control registers, and isochronous channels necessary for data transmission on the bus. AV devices (AV-devices) 11 to 13 are connected by an IEEE 1394 serial bus. Of the oPCR [0] to oPCR [2] whose transmission speed and number of oPCRs are defined by the oMPR of the AV device 13, the isochronous data whose channel is designated by the oPCR [1] is the channel # 1 of the IEEE1394 serial bus ( sent to channel # 1). Of iPCR [0] and iPCR [1] whose transmission speed and number of iPCRs are defined by iMPR of AV device 11, AV device 11 is sent to channel # 1 of the IEEE1394 serial bus by iPCR [0]. Read isochronous data. Similarly, the AV device 12 sends isochronous data to channel # 2 (channel # 2) designated by oPCR [0], and the AV device 11 starts from channel # 2 designated by iPRC [1]. Read the isochronous data.

  Using the channel secured in this way, the data transmitted from the output plug of the data transmission source device to the bus is set to be received by the input plug of the data reception destination device. The process of setting a channel and a plug and establishing a connection in this way is executed under the control of a predetermined device (controller) connected to the bus.

  In this way, data transmission is performed between devices connected by the IEEE 1394 serial bus. Here, FIG. 6 shows an example of the data structure of a packet when stream data is transmitted in the isochronous transfer mode with the IEEE 1394 serial bus.

  In FIG. 6, packets are shown in units of 1 quad red (1 quadlet = 32 bits). The first 2-quadred section is a header of an isochronous packet, and an error correction code CRC of these data is arranged together with data such as a data length, a tag, and a channel. The next 2-quadred section is called a CIP header, and is a header arranged when audio data or video data is transmitted. In this CIP header, the SID that is the node ID of the data transmission source (source device), the unit DBS of packetization of stream data, the division number FN before packetization, the number of quad reds QPC added at the time of data division, A flag SPH in the packet header of the source device, a packet loss detection counter DBC, an FMT that is the signal format ID, and the like are arranged.

  Other data corresponding to the format of stream data transmitted by isochronous packets may be arranged in the CIP header. For example, data of sampling frequency of audio data and data of a flag (N flag) indicating that rate control described later is being performed may be arranged. Following the CIP header configured in this manner, stream data having a predetermined data amount is arranged. An error correction code CRC is arranged at the end of the packet.

  Although stream data is transmitted in such a data structure, control packets such as commands and responses can be transmitted in the asynchronous transfer mode between devices connected via the IEEE 1394 serial bus. Here, the AV / C command defined as a command for controlling the devices connected via the IEEE 1394 serial bus can be used to control each device and determine the status. Data used in the AV / C command will be described below.

  FIG. 7 shows the data structure of a packet when a command or response is transmitted as an AV / C command. In this AV / C command, the command and response are transmitted in the asynchronous transfer mode. The AV / C command is a command set for controlling the AV device, and CTS (command set ID) = “0000”. In order not to put a burden on the bus and AV equipment, the response to the command is performed within 100 ms. The packet shown in FIG. 7 is also shown in units of 1 quadred. The first five quad red sections are the header part of the packet, and the remaining part is the data block.

  The destination ID in the header part indicates the destination. CTS indicates the ID of the command set. In the AV / C command set, CTS = “0000”. The ctype / response field indicates the function classification of the command when the packet is a command, and indicates the processing result of the command when the packet is a response.

  The commands are broadly divided into (1) a command for controlling the function from the outside (CONTROL), (2) a command for inquiring the state from the outside (STATUS), and (3) a command for inquiring from outside whether or not the control command is supported (GENERAL INQUIRY). Four types are defined: (whether or not opcode is supported), SPECIFIC INQUIRY (whether or not opcode and operands are supported), and (4) a command (NOTIFY) that requests a change in state.

  Responses are returned according to the type of command. Responses to the CONTROL command include NOT IMPLEMENTED (not implemented), ACCEPTED (accept), REJECTED (reject), and INTERIM (provisional response). Responses to the STATUS command include NOT INPLEMENTED, REJECTED, IN TRANSITION (in transition), and STABLE (stable). Responses to GENERAL INQUIRY and SPECIFIC INQUIRY commands include IMPLEMENTED (implemented) and NOT IMPLEMENTED. Responses to the NOTIFY command include NOTIMPLEMENTED, REJECTED, INTERIM, and CHANGED (changed). Note that commands and responses other than those shown here may be defined.

  The subunit type (subunit type) is provided to specify the function in the device, and for example, tape recorder / player, tuner, etc. are assigned. In order to determine when there are a plurality of subunits of the same type, addressing is performed with a unit id as a determination number. “opcode” represents a command, and “operand” represents a parameter of the command. Additional operands are fields that are added as necessary. Padding is also a field added as necessary. A data CRC (Cyclic Redundancy Check) is an error correction code used for error checking during data transmission.

  FIG. 8 shows a specific example of the AV / C command. FIG. 8A shows a specific example of ctype / response. The upper part of the figure represents a command, and the lower part of the figure represents a response. “0000” is assigned CONTROL, “0001” is assigned STATUS, “0010” is assigned SPECIFIC INQUIRY, “0011” is assigned NOTIFY, and “0100” is assigned GENERAL INQUIRY. “0101 to 0111” are reserved for future specifications. “1000” is NOT INPLEMENTED, “1001” is ACCEPTED, “1010” is REJECTED, “1011” is IN TRANSITION, “1100” is IMPLEMENTED / STABLE, “1101” is CHNGED, “1111” "INTERIM" is assigned to "." “1110” is reserved for future specifications.

  FIG. 8B shows a specific example of the unit type. “00000” is a Video Monitor, “00011” is a disk recorder / player, “00100” is a tape recorder / player, “00101” is a Tuner, “00111” is a VideoCamera, “11100” is a Vendor unique, “11110” is assigned Subunit type extended to next byte. Note that “11111” is assigned a unit, but this is used when it is sent to the device itself, for example, turning on / off the power.

  FIG. 8C shows a specific example of opcode. There is an opcode table for each subunit type, and here, the opcode is shown when the subunit type is Tape recorder / Player. An operand is defined for each opcode. Here, “00h” is VENDOR-DEPENDENT, “50h” is SEARCH MODE, “51h” is TIMECODE, “52h” is ATN, “60h” is OPEN MIC, “61h” is READ MIC, “62h” is assigned WRITE MIC, “C1h” is assigned LOAD MEDIAUM, “C2h” is assigned RECORD, “C3h” is assigned PLAY, and “C4h” is assigned WIND.

  Using the AV / C command defined in this way, the devices connected to the bus are controlled, and data transmission is performed between the devices connected via the bus based on the control. Note that only typical commands, responses, and subunit types shown in FIG. 8 are shown. Other commands and responses are also defined, and undefined values are added to other commands and sub-units in the future. Unit type etc. may be defined.

  Next, a case where stream data such as audio data is transmitted in the content transmission system SYS1 of the present embodiment will be described.

  Here, the disk playback device 1 becomes an audio data transmission device (source device), and the audio data sent from the disk playback device 1 to the bus 9 is received by the amplifier device 3 which is a reception device (sink device). In this example, music is output (sound emission) from the speakers 3d and 3e connected to the amplifier device 3.

  In the case of the present embodiment, rate control is performed so that audio data is transmitted as stream data from the disk reproducing device 1 to the amplifier device 3. First, the state in which this rate control is performed will be described with reference to FIG. The source device shown in FIG. 9 corresponds to the disc playback device 1 that outputs audio data to the network (bus 9), and the sink device corresponds to the amplifier device 3 that inputs audio data from the network. Data (command and response) transmitted for rate control between the disc reproducing apparatus 1 and the amplifier apparatus 3 is data configured as the AV / C command described above.

  First, the amplifier device 3 sends a base configuration subfunction of a rate control command for instructing a reference rate for rate control to the disk reproducing device 1 (step S1), and the amplifier device 3 confirms a response to this command (step S1). S2). Next, the amplifier device 3 sends a sync select subfunction of a rate control command for instructing execution of rate control to the disc playback device 1 (step S3). Receiving this command, the disc playback apparatus 1 sends a response indicating that the process for the command has been performed normally to the amplifier apparatus 3 (step S4). At this time, the disk playback device 1 becomes a target device that completes rate control (command-based rate control), and stores the node ID of the amplifier device 3 that is a controller related to rate control. As a result, in the disk reproducing apparatus 1, it is understood that the amplifier device 3 as a controller is an input device for stream data controlled by rate control.

  Thereafter, when it is necessary to change the rate at which stream data is transmitted by rate control, the amplifier device 3 as a controller sends a flow control subfunction of a rate control command to the disc playback device 1 (step S7), and responds to the command. The response is confirmed (step S8). As the data value corresponding to the rate specified in this command, an appropriate transmission rate is set depending on the state of signal processing inside the stream data input by the amplifier device 3. Further, while the rate control is continuously completed, the amplifier device 3 as the controller must send the flow control subfunction of the rate control command to the disc playback device 1 repeatedly at an arbitrary time within 5 seconds as the command interval. Don't be. In FIG. 9, this flow control subfunction is omitted. In this way, stream data is transmitted via the bus 9 in a state where flow control is performed using the amplifier device 3 as an input device as a controller.

  After the disc player 1 becomes the target device that completes this rate control, it sends a path change subfunction of the input select control command to the amplifier device 3 that is the input device of the stream data (step S5). Upon receiving a response to this command (step S6), the disc playback apparatus 1 checks the input plug of the stream data of the amplifier apparatus 3, the subunit connected internally to this input plug, and the destination plug of the subunit. .

  Next, processing when the audio data format is changed in the middle while audio data is being transmitted from the disk reproducing device 1 to the amplifier device 3 via the bus 9 will be described. Here, two content data A and content data B are recorded as audio data on the optical disc 101 to be played back by the disc playback apparatus 1, and a playback operation for playing back the content data B is performed following playback of the content data A. Shall.

  Various changes can be considered for the difference between the format of the content data A and the format of the content data B. For example, the sampling frequency may change. Also, the number of channels may change. Even when there is no change in the sampling frequency, the number of channels, etc., the data structure may change due to a difference in the standard of content data (audio data). As a change in the stream data configuration due to the difference in the standard, for example, there is a case where the format is changed from a format specified in IEC60958 to a format specified as DVD audio.

  As described above, when the format of the audio data changes, for example, when the value in the CIP header added to the isochronous transfer packet shown in FIG. 7 described above changes to the value of the corresponding format, There are cases where the value of the CIP header does not change even if it changes.

  A processing example in each case will be described. First, an example in which the sampling frequency is changed between the content data A and the content data B, and data indicating the sampling frequency included in the CIP header is changed. Will be described with reference to FIG.

  In the example of FIG. 10, it is assumed that the content data A has a sampling frequency SFC = X and the content data B has a sampling frequency SFC = Y. As shown in FIG. 10A, when the optical disc 101 in which the content data A and the content data B are recorded is reproduced by the disc reproducing apparatus 1, the content data A is changed as shown in FIG. The output data is output from the output plug oPCR to the bus 9 in the isochronous transfer mode using a predetermined transmission channel, and the content data A is input from the input plug iPCR of the amplifier device 3 as shown in FIG. As shown in FIG. 10 (D), music based on the content data A is output from the speakers 3 d and 3 e connected to the amplifier device 3. Here, the rate control is performed as an example. In the amplifier device 3, the input content data A is temporarily stored in the internal buffer memory and then processed, and is delayed by the time stored in the buffer memory. Thus, music is output from the speakers 3d and 3e.

  Here, it is assumed that the reproduction of the content data A ends at the timing t11. At this time, the process proceeds to playback of the content data B. At this time, the CPU 110 of the disk playback apparatus 1 detects that the formats of the content data A and the content data B are different, and the playback state of the optical disk 101 is set to the playback pause. State. Then, invalid data having the same format as the content data A is output from the output plug oPCR of the disc playback apparatus 1 in the channel where the content data A has been output. Here, the invalid data (hereinafter referred to as content A invalid data) includes audio data of volume level 0 having the same format as the content data A, auxiliary data (Ancillary data) associated with the audio data, It consists of data indicating that the audio data is invalid data (No-data).

  The disc playback apparatus 1 outputs the content A invalid data to the bus 9 until a timing t12 when a relatively short time (for example, several tens of ms) has elapsed from the playback end timing t11 of the content data A.

  At time t12, invalid data having the same format as the content data B is output from the output plug oPCR of the disc playback apparatus 1. Here, the invalid data (hereinafter referred to as content B invalid data) includes audio data of volume level 0 having the same format as the content data B, auxiliary data (Ancillary data) associated with the audio data, It is composed of data indicating that the audio data is invalid data (No-data).

  As the data input from the input plug iPCR of the amplifier device 3, as shown in FIG. 10C, the input of the content data A is completed at the timing t21 in accordance with the end of the playback of the content data A in the disc playback device 1. From time t21 to time t22, content A invalid data is input, and after time t22, content B invalid data is input. When the content B invalid data is input, the amplifier device 3 receives the sampling frequency data included in the CIP header of the invalid data transmitted from the disc playback device 1 at a timing t23 slightly after the input start timing t22. Based on the above, it is detected that data having sampling frequency SFC = Y (that is, content B invalid data) is starting to be input.

  When the content B invalid data is transmitted to the bus 9, the disc playback device 1 sends an input plug signal format status command to check the state of the input plug of the amplifier device 3 (step S11). The input plug whose state is checked here is the input plug confirmed by the path change subfunction of the input select control command shown in step S5 of FIG.

  The command in step S11 is configured as shown in FIG. 11, for example. That is, [INPUT PLUGSIGNAL FORMAT] data corresponding to the corresponding command is arranged in the [opcode] section, and data specifying the plug whose state is to be checked is arranged in the [operand (0)] section. The maximum value FF is arranged in the section after operand (1)]. This data is arranged in the packet configuration shown in FIG.

  When such a command is transmitted from the disk reproducing apparatus 1 to the amplifier apparatus 3 via the bus 9 in step S11, the amplifier apparatus 3 returns a response to the input plug signal format status command to the disk reproducing apparatus 1. (Step S12). In this response, the command data is arranged as it is in the [opcode] and [operand (0)] sections of the command, and the input processing is performed by the subunits in the section after [operand (1)]. Data in the FMT and FDF sections of the data CIP header is arranged.

  Here, in the case of the present embodiment, when the amplifier device 3 tries to transmit a response in step S12 shown in FIG. 10, it still executes the output process for the content data A as shown in FIG. Therefore, the FMT and FDF data of the CIP header in the format of the content data A is transmitted to the disc playback apparatus 1 as the response. Based on the response, the disc playback device 1 recognizes that the amplifier device 3 is still performing the output process for the content data A and has not switched to the state for accepting the content data B.

  Then, the disc playback apparatus 1 maintains the current stream data output (content B invalid data output) and the same input plug signal format status command as in step S11 every time a predetermined time (for example, about 200 ms) elapses. And a process of receiving a response corresponding to this from the amplifier device 3 (hereinafter referred to as a polling process) is repeatedly executed. The disc reproducing device 1 repeats this polling process until it can be recognized that the amplifier device 3 has been switched to the state of accepting the content data B.

  As shown in FIG. 10D, when the output of the content data A stored in the buffer memory of the amplifier device 3 is completed at timing t24, the amplifier device 3 uses the sampling frequency SFC = Y (that is, the content data B). ) Is performed so that the processing state in the subunit is switched so that the content data B can be received. As a result, the content data B can be received. When the amplifier device 3 subsequently receives the input plug signal format status command (step S13), the response in which the FMT and FDF data of the CIP header of the data having the same format as the content data B received at this time is arranged. Is transmitted to the disc reproducing apparatus 1 (step S14).

  Thus, when receiving this response at timing t13, the disc reproducing device 1 recognizes that the amplifier device 3 has been switched to a state of accepting the content data B based on the received response.

  Then, at time t14 when a predetermined time (for example, several tens of ms) has elapsed from timing t13, the disc playback device 1 changes the content B invalid data output from the disc playback device 1 to valid data at this time. However, here, a mute signal whose volume level is 0 level (silenced state) is output until timing t15 when a relatively short time (for example, several hundred ms) elapses. Here, the mute signal can be used to determine the format of the content data B, and the amplifier device 3 can make all internal settings for signal processing, and can mute the inside of the amplifier device 3 and its output music. (Ancillary data) is included.

  At timing t15, as shown in FIG. 10A, the disc playback apparatus 1 releases the playback pause of the optical disc 101 and starts playback of the content data B, as shown in FIG. 10B. Then, the content data B starts to be output to the bus 9.

  The content data B started to be transmitted in this way is input at the timing t25 in the amplifier device 3, and at a timing t26 when some processing time for buffer memory accumulation and data processing elapses from the timing t25. The mute state is released, and music based on the content data B is output from the speakers 3e and 3d connected to the amplifier device 3.

  As described above, since the disc reproducing device 1 confirms that the amplifier device 3 has been switched to the state of accepting the content data B, the transmission of the content data B is started. The music based on can be released without breaking the head.

  By the way, in the case of the present embodiment in addition to such a configuration, the disc playback apparatus 1 has the format of content data B to be output next to the amplifier apparatus 3 (hereinafter referred to as this) at the timing t11 when the playback of the content data A ends. Is also called a content B format), and a plug for confirming whether the amplifier device 3 corresponds to the detected content B format and receiving content data B in the content B format is provided. In order to confirm whether or not the amplifier device 3 can be configured at present, a stream format support status command is sent to the amplifier device 3 (step S101).

  The stream format support status command in step S101 has a configuration shown in FIG. 12, for example. That is, [STREAM FORMAT SUPPORT] data corresponding to the command is arranged in the [opcode] section, and [INPUT] data indicating the input plug is arranged in the [operand (0)] section. In the section of [operand (1)], data for specifying the reception capability and the plug for checking the status of the reception capability are arranged, and [operand (2)], [operand (9)], [operand (16)] The maximum value FF is arranged in the interval. In this case, the sections of [operand (3)-(8)], [operand (10)-(15)], [operand (17)-(22)] Data for specifying the format is arranged, for example, as shown in FIG.

  In the configuration of FIG. 13, data specifying the format shown in FIG. 14 is arranged in the sections [operand (3)], [operand (10)], and [operand (17)]. For example, when the audio & music data shown in FIG. 14 is arranged in the sections [operand (3)], [operand (10)], and [operand (17)], [operand (4)-( 8)], [operand (11)-(15)], [operand (18)-(22)], [operand (3)], [operand (10)], [operand (17)] Data for further specifying the format data arranged in the section is arranged, for example, as shown in FIG.

  In the case of the configuration of FIG. 15, data specifying the format shown in FIG. 16 is arranged in the sections [operand (4)], [operand (11)], and [operand (18)], and [operand ( 5)], [operand (12)], and [operand (19)], data for further specifying the format of FIG. 16 shown in FIG. 17 is arranged, and [operand (6)], [operand ( 13)], [operand (20)] are reserved sections, [operand (7)-(8)], [operand (14)-(15)], [operand (21)-(22) ], Data of attributes for supplementing the format is arranged. This data is arranged in the packet configuration shown in FIG.

  When the amplifier device 3 receives such a stream format support status command from the disc playback device 1 via the bus 9, the amplifier device 3 transmits a response to the stream format support status command to the disc playback device 1 (step S102).

  In this response, the commands [opcode], [operand (0)], [operand (1)], [operand (3)-(8)], [operand (10)-(15)], [operand ( 17)-(22)], command data is arranged as it is, and [operand (3)-() in the [operand (2)], [operand (9)], [operand (16)] sections. 8)], [operand (10)-(15)], [operand (17)-(22)], for example, a support status (Support_status) as shown in FIG. (Hereinafter, this is referred to as support status data) is arranged.

  The support status data indicates, for example, whether or not the amplifier device 3 supports the content B format (supported / not supported), and a plug for receiving the content data B in the content B format is connected to the amplifier device. 3 indicates whether or not the current configuration is possible (configured / not configured). Details of the support status data are described on page 27 of Non-Patent Document 1 “TA Document 2001002 AV / C Stream Format Information Specification 1.0”.

  Thus, the disc playback apparatus 1 can recognize whether or not the amplifier apparatus 3 supports the content B format based on the response from the amplifier apparatus 3, and the content data in the content B format in the amplifier apparatus 3. It can be recognized whether or not a plug for receiving B can be configured at present.

  When the disc player 1 recognizes that the amplifier device 3 is compatible with the content B format and that the amplifier device 3 can configure a plug for receiving the content data B in the content B format. Based on the recognition result, the amplifier device 3 determines that the content data B can be switched to the acceptance state, and as described above, the polling process for confirming whether or not the state is switched to the acceptance state. (Steps S11... S14) are started.

  On the other hand, the disc player 1 does not support the content B format in the amplifier device 3 or cannot currently configure a plug for receiving the content data B in the content B format in the amplifier device 3. Is recognized based on the recognition result, it is determined that the amplifier device 3 cannot be switched to the receiving state for accepting the content data B, and as described above, whether or not the switching has been switched to the receiving state is confirmed. Including the polling process (steps S11..., S14), and subsequent processes are stopped.

  In this way, the disc playback apparatus 1 can be switched to the receiving state in the first place before confirming with the amplifier apparatus 3 whether or not the switching to the receiving state for receiving the content data B in the content B format is accepted. Whether or not it is confirmed with the amplifier device 3.

  Next, an example in which the N flag of stream data changes will be described with reference to FIG. In the example of FIG. 10, the sampling frequency changes, but the value of the N flag may change. As described above, this N flag is a flag that changes depending on the presence or absence of flow control (rate control). For example, N flag = 1 is set for stream data whose transmission rate is controlled by flow control. For the stream data whose transmission rate is not controlled by N, N flag = 0. Here, it is assumed that N flag = 1 for content data A and N flag = 0 for content data B. Here, it is assumed that data indicating the value of the N flag is included in the CIP header.

  As shown in FIG. 19A, the content data A is reproduced by the disc reproducing apparatus 1, so that the content data A uses a predetermined transmission channel from the output plug oPCR as shown in FIG. 19B. Then, the data is output to the bus 9 in the isochronous transfer mode, and the content data A is input from the input plug iPCR of the amplifier device 3 as shown in FIG. 19C, and the amplifier device 3 as shown in FIG. 19D. Music based on the content data A is output from the speakers 3d and 3e connected to. Since the content data A is stream data in which the transmission rate is controlled by flow control, the amplifier device 3 is configured to temporarily store the input content data A in a buffer memory before processing the buffer. Music is output from the speakers 3d and 3e with a delay of the time accumulated in the memory.

  Here, it is assumed that the reproduction of the content data A ends at the timing t11 ′. At this time, the process proceeds to playback of the content data B. At this time, the CPU 110 of the disk playback apparatus 1 determines that the types (N flag here) of the content data A and the content data B are different, and the optical disk 101. Is set as a playback pause state. Then, the output plug oPCR of the disc playback apparatus 1 outputs invalid data having the same format as the content data A (hereinafter also referred to as “content A invalid data”) in the channel from which the content data A was output. Here, the content A invalid data includes audio data of volume level 0 having the same format as the content data A (that is, N flag = 1), auxiliary data (Ancillary data) accompanying the audio data, and invalid audio data. It consists of data indicated as data (No-data).

  The content A invalid data is output to the bus 9 until a timing t12 ′ when a relatively short time (for example, several tens of ms) has elapsed from the reproduction end timing t11 ′ of the content data A.

  Then, at the timing t12 ′, the disc playback device 1 outputs invalid data having the same format as the content data B (hereinafter also referred to as content B invalid data) from the output plug oPCR of the disc playback device 1. Here, the content B invalid data includes audio data of volume level 0 having the same format as the content data B (that is, N flag = 0), auxiliary data (Ancillary data) accompanying the audio data, and invalid audio data. Data indicating that it is data (No-data).

  As data to be input from the input plug iPCR of the amplifier device 3, as shown in FIG. 19C, the input of the content data A is completed at the timing t21 ′, and the content A is invalid from the timing t21 ′ to the timing t22 ′. Data is input, and content B invalid data is input after timing t22 '. When the content B invalid data is input, the amplifier apparatus 3 detects that the N flag in the CIP header of the data has changed from 1 to 0 at a timing t23 ′ slightly after timing t22 ′. Based on this, it is recognized that the stream data (content B invalid data) whose transmission rate is not controlled by the flow control is obtained.

  When the content B invalid data is transmitted to the bus 9, the disc playback device 1 sends an input plug signal format status command to check the state of the input plug of the amplifier device 3 (step S11 '). The input plug whose state is checked here is the input plug confirmed by the path change subfunction of the input select control command shown in step S5 of FIG.

  The input plug signal format status command in step S11 ′ is configured as shown in FIG. 11, for example. That is, the data of [INPUT PLUG SIGNAL FORMAT], which is the corresponding command, is arranged in the [opcode] section, and the data specifying the plug whose state is to be checked is arranged in the [operand (0)] section. The maximum value FF is arranged in the section after [operand (1)]. These data are arranged in the packet shown in FIG.

  When such an input plug signal format status command is transmitted from the disk reproducing apparatus 1 to the amplifier apparatus 3 via the bus 9 in step S11 ′, the amplifier apparatus 3 sends a response to the input plug signal format status command to the disk It is returned to the playback device 1 (step S12 '). In this response, the command data is arranged as it is in the [opcode] and [operand (0)] sections of the command, and the input processing is performed by the subunit at this time in the sections after [operand (1)]. The data of the FMT and FDF sections of the CIP header of the existing data is arranged.

  Here, in the case of the present embodiment, when a response is sent in step S12 ′ shown in FIG. 19, the amplifier apparatus 3 still outputs the content data A as shown in FIG. 19D. Therefore, a response indicating that the stream data (content data A) whose transmission rate is controlled by the flow control is accepted is returned. Based on the response, the disc playback device 1 recognizes that the amplifier device 3 has not yet been switched to a state of accepting the content data B.

  Then, the disc playback apparatus 1 maintains the current stream data output (content B invalid data output) and the same input plug signal format status as in step S11 ′ every time a predetermined time (for example, about 200 ms) elapses. A process of transmitting a command and receiving a response corresponding to the command from the amplifier device 3 (polling process) is repeatedly executed. The disc reproducing device 1 repeats this polling process until it can be recognized that the amplifier device 3 has been switched to the state of accepting the content data B.

  As shown in FIG. 19D, when the output of the content data A stored in the buffer memory of the amplifier device 3 is completed at the timing t24 ', the amplifier device 3 uses the data whose transmission rate is not controlled by the flow control. A switching process for switching the processing state so that (content data B) can be accepted is executed, and as a result, the content data B can be accepted. Then, when receiving the input plug signal format status command (step S13 '), the amplifier device 3 transmits a response for notifying the switching to the acceptance state for accepting the content data B to the disc reproducing device 1. (Step S14 ').

  Thus, the disc reproducing device 1 recognizes that the amplifier device 3 has been switched to the state of accepting the content data B by receiving this response at the timing t13 ′.

  Then, the disc playback apparatus 1 changes the content B invalid data output from the disc playback apparatus 1 to valid data at the timing t14 ′ when a predetermined time (for example, several tens of ms) has elapsed from the timing t13 ′. However, here, a mute signal whose volume level is 0 level (silenced state) is output until a timing t15 ′ when a relatively short time (for example, several hundred ms) elapses. Here, the mute signal can be used to determine the format of the content data B, the amplifier device 3 can perform all internal settings for signal processing, and mute the inside of the amplifier device 3 and its output audio. Includes auxiliary data (Ancillary data).

  At time t15 ′, as shown in FIG. 19A, the disc playback apparatus 1 cancels the playback pause of the optical disc 101 and starts playback of the content data B, as shown in FIG. 19B. Thus, the output of the content data B is started.

  The content data B started to be transmitted in this way is input at the timing t25 ′ in the amplifier device 3, and muted at the timing t26 ′ when some processing time for data processing has elapsed from the timing t25 ′. The state is released, and music based on the content data B is output from the speakers 3e and 3d connected to the amplifier device 3.

  Thus, even when the stream data changes due to the change of the N flag, complete data transmission and processing without missing such as so-called head break can be performed as in the case of the change of the sampling frequency.

  By the way, in the case of the present embodiment in addition to such a configuration, the disc playback device 1 formats the content data B to be output to the amplifier device 3 next (content B) at the timing t11 ′ when the playback of the content data A is finished. In order to check whether the amplifier device 3 corresponds to the detected content B format and to receive the content data B in the content B format, the amplifier device 3 In order to confirm whether or not it is possible to configure, the above stream format support status command is sent to the amplifier device 3 (step S101 ').

  When receiving the stream format support status command from the disc playback device 1 via the bus 9, the amplifier device 3 transmits a response similar to the response in step S102 described above to the disc playback device 1 (step S102 ′). .

  Thus, the disc playback apparatus 1 can recognize whether or not the amplifier apparatus 3 supports the content B format based on the response from the amplifier apparatus 3, and the content data in the content B format in the amplifier apparatus 3. It can be recognized whether or not a plug for receiving B can be configured at present.

  Based on such a response, the disc playback apparatus 1 configures a plug for receiving the content data B in the content B format in the amplifier apparatus 3 that the amplifier apparatus 3 supports the content B format. If the amplifier device 3 recognizes that the content data B can be received, the amplifier device 3 determines that the content data B can be switched to the receiving state for receiving the content data B, and confirms whether or not the switching has been made to the receiving state as described above. Polling processing (steps S11 ′,..., S14 ′) is started.

  On the other hand, the disc playback apparatus 1 indicates that the amplifier apparatus 3 does not support the content B format, or that the amplifier apparatus 3 cannot currently configure a plug for receiving the content data B in the content B format. If recognized, based on this recognition result, the amplifier device 3 determines that it cannot switch to the acceptance state for accepting the content data B, and includes a polling process for confirming whether or not the state has been switched to the acceptance state. The subsequent processing is stopped.

  In this way, the disc playback apparatus 1 can be switched to the receiving state in the first place before confirming with the amplifier apparatus 3 whether or not the switching to the receiving state for receiving the content data B in the content B format is accepted. Whether or not it is confirmed with the amplifier device 3.

  10 and 19 described so far are examples in which a change in stream data can be detected from the CIP header added to the stream data. However, a change in stream data cannot be detected from the CIP header. An example of this will be described next. The latter is a process that can also be applied when a change can be detected in the CIP header.

  First, FIG. 20 shows an example of a case where the format has changed with no change in the CIP header. In the following, it is assumed that the content data A is in the IEC60958 format and the content data B is in the DVD audio format.

  As shown in FIG. 20 (A), the content data A is played back by the disc playback device 1, so that the content data A uses a predetermined transmission channel from the output plug oPCR as shown in FIG. 20 (B). In the isochronous transfer mode, the content data A is input from the input plug iPCR of the amplifier device 3 as shown in FIG. 20 (C), and the amplifier device as shown in FIG. 20 (D). Music based on the content data A is output from the speakers 3e and 3d connected to 3. In the amplifier device 3, the input content data A is temporarily stored in the buffer memory and then processed, and music is output from the speakers 3e and 3d with a delay by the time stored in the buffer memory. .

  Here, it is assumed that the reproduction of the content data A ends at the timing t31. At this time, the process proceeds to playback of the content data B. At this time, the CPU 110 of the disk playback apparatus 1 determines that the formats of the content data A and the content data B are different, and the playback state of the optical disk 101 is set to the playback pause. State. Then, the content plug APCR outputs the content A invalid data from the output plug oPCR of the disc playback apparatus 1 through the channel from which the content data A has been output. Here, the content A invalid data is audio data of volume level 0 having the same format as the content data A, auxiliary data (Ancillary data) accompanying the audio data, and data (No-data) in which the audio data is invalid. It is composed of data shown to be.

  The content A invalid data is output to the bus 9 until a timing t32 when a relatively short time (for example, several tens of ms) elapses from the reproduction end timing t31 of the content data A.

  At timing t32, an empty packet without actual data called an empty packet is transmitted as an isochronous packet for stream data transmission. The empty packet is transmitted for a period of 1 ms or more, for example. Thereafter, the content B invalid data is output from the output plug oPCR of the disc playback apparatus 1 at timing t33. Here, the content B invalid data is audio data of volume level 0 having the same format as the content data B, auxiliary data (Ancillary data) accompanying the audio data, and data (No-data) in which the audio data is invalid. It consists of data that is shown to exist.

  Further, the disc playback apparatus 1 transmits a mute signal in the same DVD audio format as the content data B as stream data from timing t34 after transmitting the content B invalid data for a predetermined time from timing t33. Here, the mute signal is data for determining the format of the content data B, allowing the amplifier device 3 to make all internal settings for signal processing, and muting the inside of the amplifier device 3 and its output audio. Ancillary data accompanying the data is included.

  As data to be input from the input plug iPCR of the amplifier device 3, as shown in FIG. 20C, the input of the content data A is completed at timing t41, and content A invalid data is input from timing t41 to timing t42. Then, an empty packet is input from timing t42 to timing t43. Further, after timing t43, the content B invalid data is input. When the content B invalid data is input, the amplifier device 3 directly detects a change in the format of the data from the input content B invalid data itself. In this detection, since an empty packet with no actual data is transmitted and then data with a changed format is transmitted, the format change can be detected in a relatively short time.

  When the content B invalid data is transmitted to the bus 9, the disc playback device 1 sends a signal source status command of an AV / C command to check the status of the amplifier device 3 (step S21).

  Subsequently, the disc playback device 1 receives a response to the signal source status command from the amplifier device 3, and determines whether or not the amplifier device 3 has been switched to a state of accepting the content data B based on the received response. (Step S22).

  Here, in the case of the present embodiment, when the amplifier device 3 tries to transmit the response of step S22 to the disc playback device 1, as shown in FIG. 20 (D), it still outputs the content data A. Since it is in the state, a signal for notifying that it has not yet been switched to the state of accepting the content data B is transmitted to the disc playback apparatus 1 as the response. Based on this response, the disc playback device 1 recognizes that the amplifier device 3 has not switched to a state in which the content data B is accepted.

  Then, the disc playback apparatus 1 transmits the same command as the command transmitted in step S21 each time a predetermined time (for example, about 200 ms) passes while maintaining the current stream data output (mute signal), and A process (polling process) for receiving a response corresponding to this from the amplifier device 3 is repeatedly executed. The disc reproducing device 1 repeats this polling process until it can be recognized that the amplifier device 3 has been switched to the state of accepting the content data B.

  As shown in FIG. 20D, in the amplifier device 3, the output of the content data A stored in the buffer memory is finished at the timing t45 so that the circuit in the amplifier device 3 can process the content data B. For example, a downmix coefficient for a DVD audio format is acquired, and the acquired coefficient is set. When the signal source status command is received from the disc playback apparatus 1 in step S23 after the switching process for processing the content data B is performed, the amplifier apparatus 3 has been switched to the state of accepting the content data B. Is sent to the disc player 1 (step S24).

  Thus, by receiving this response, the disc playback device 1 recognizes that the amplifier device 3 has been switched to a state of accepting the content data B.

  Then, the disc reproducing apparatus 1 stops the mute signal output from the disc reproducing apparatus 1 at this time t35 immediately after receiving the response, and reproduces the optical disc 101 as shown in FIG. The pause is released, the reproduction of the content data B is started, and the output of the content data B is started as shown in FIG.

  The content data B started to be transmitted in this way is input at the timing t46 in the amplifier device 3, and at the timing t47 when some processing time for buffer memory accumulation and data processing elapses from the timing t46. The mute state is released, and music based on the content data B is output from the speakers 3d and 3e connected to the amplifier device 3.

  Even when the format changes in a state where there is no change in the header of the audio data (content data A and content data B) transmitted in this way, complete data transmission and processing can be performed without omissions such as head loss. become.

  By the way, in the case of the present embodiment in addition to such a configuration, the disc playback device 1 formats the content data B to be output next to the amplifier device 3 (content B format) at the timing t31 when the playback of the content data A is finished. ) Is detected, the amplifier device 3 is currently configured with a plug for confirming whether the amplifier device 3 corresponds to the detected content B format and for receiving the content data B in the content B format. In order to confirm whether or not it is possible, the above-described stream format support status command is sent to the amplifier device 3 (step S201).

  When the amplifier apparatus 3 receives such a stream format support status command from the disk reproducing apparatus 1 via the bus 9, the amplifier apparatus 3 transmits a response similar to the response in step S102 described above to the disk reproducing apparatus 1 (step S202).

  Thus, the disc playback apparatus 1 can recognize whether or not the amplifier apparatus 3 supports the content B format based on the response from the amplifier apparatus 3, and the content data in the content B format in the amplifier apparatus 3. It can be recognized whether or not a plug for receiving B can be configured at present.

  Based on such a response, the disc playback apparatus 1 configures a plug for receiving the content data B in the content B format in the amplifier apparatus 3 that the amplifier apparatus 3 supports the content B format. If the amplifier device 3 recognizes that the content data B can be received, the amplifier device 3 determines that the content data B can be switched to the receiving state for receiving the content data B, and confirms whether or not the switching has been made to the receiving state as described above. Polling processing (steps S21,..., S24) is started.

  On the other hand, the disc playback apparatus 1 indicates that the amplifier apparatus 3 does not support the content B format, or that the amplifier apparatus 3 cannot currently configure a plug for receiving the content data B in the content B format. If recognized, based on this recognition result, the amplifier device 3 determines that it cannot switch to the acceptance state for accepting the content data B, and includes a polling process for confirming whether or not the state has been switched to the acceptance state. The subsequent processing is stopped.

  In this way, the disc playback apparatus 1 can be switched to the receiving state in the first place before confirming with the amplifier apparatus 3 whether or not the switching to the receiving state for receiving the content data B in the content B format is accepted. Whether or not it is confirmed with the amplifier device 3.

  Next, as an example of using the signal source status command in a state where the CIP header changes, an example in which the N flag changes will be described with reference to FIG. In this example, it is assumed that the content data A is N flag = 1 and the content data B is N flag = 0.

  As shown in FIG. 21 (A), the content data A is played back by the disc playback device 1 so that the content data A uses a predetermined transmission channel from the output plug oPCR as shown in FIG. 21 (B). Then, the data is output to the bus 9 in the isochronous transfer mode, and the content data A is input from the input plug iPCR of the amplifier device 3 as shown in FIG. 21C, and the amplifier device 3 as shown in FIG. Music based on the content data A is output from the speakers 3d and 3e connected to. Since the content data A is stream data whose transmission rate is controlled by rate control, the amplifier device 3 is configured to temporarily store the input content data A in a buffer memory before processing the buffer. Music is output from the speakers 3d and 3e with a delay of the time accumulated in the memory.

  Here, it is assumed that the reproduction of the content data A ends at the timing t31 ′. At this time, the process proceeds to playback of the content data B. At this time, the CPU 110 of the disk playback apparatus 1 determines that the N flag is different for the content data A and the content data B, and the playback state of the optical disk 101 is played back. Set to pause state. Then, the content plug APCR outputs the content A invalid data from the output plug oPCR of the disc playback apparatus 1 through the channel from which the content data A has been output. Here, the content A invalid data includes audio data of volume level 0 having the same format as the content data A (that is, N flag = 1), auxiliary data (Ancillary data) accompanying the audio data, and invalid audio data. It consists of data indicated as data (No-data).

  The content A invalid data is output to the bus 9 until a timing t32 ′ when a relatively short time (for example, several tens of ms) has elapsed from the reproduction end timing t31 ′ of the content data A.

  Then, at time t32 ', the disc reproducing apparatus 1 transmits an empty packet without actual data called an empty packet as an isochronous packet for stream data transmission. The empty packet is transmitted for a period of 1 ms or more, for example. Thereafter, invalid data (content B invalid data) having the same format as that of the content B is output from the output plug oPCR of the disc playback apparatus 1 at timing t33 ′.

  Further, the disc player 1 transmits a mute signal in the same format as the content data B from the timing t34 ′ after transmitting the content B invalid data for a predetermined time from the timing t33 ′. Here, the mute signal is data for determining the format of the content data B, allowing the amplifier device 3 to make all internal settings for signal processing, and muting the inside of the amplifier device 3 and its output audio. Ancillary data accompanying the data is included.

  As data to be input from the input plug iPCR of the amplifier device 3, as shown in FIG. 21C, the input of the content data A is completed at the timing t41 ′, and the content A is invalid from the timing t41 ′ to the timing t42 ′. Data is input, and an empty packet is input from timing t42 'to timing t43'. Further, after the timing t43 ′, the content B invalid data is input. When the content B invalid data is input, the amplifier apparatus 3 changes the N flag in the CIP header to 0, the stream data whose transmission rate is controlled by flow control is lost, and the input A change in the data format is detected directly from the stream data (content B invalid data) itself. In this detection, since the content B invalid data whose format has changed after the empty packet without actual data is transmitted, the format change can be detected in a relatively short time.

  When the content data B invalid data is transmitted to the bus 9, the disc playback device 1 sends a signal source status command of an AV / C command to check the status of the amplifier device 3 (step S21 '). .

  Subsequently, the disc playback device 1 receives a response to the signal source status command from the amplifier device 3, and determines whether or not the amplifier device 3 has been switched to a state of accepting the content data B based on the received response. (Step S22 ').

  Here, in the case of the present embodiment, when the amplifier device 3 tries to transmit the response of step S22 ′ to the disc playback device 1, it still outputs the content data A as shown in FIG. As a response, a signal for notifying that the content data B has not yet been switched to is sent to the disc playback apparatus 1 as the response. Based on this response, the disc playback device 1 recognizes that the amplifier device 3 has not switched to a state in which the content data B is accepted.

  Then, the disc reproducing apparatus 1 transmits the same command as the command transmitted in step S21 ′ every time a predetermined time (for example, about 200 ms) elapses while maintaining the current stream data output (mute signal), and Then, a process (polling process) of receiving a response corresponding to this from the amplifier device 3 is repeatedly executed. The disc reproducing device 1 repeats this polling process until it can be recognized that the amplifier device 3 has been switched to the state of accepting the content data B.

  As shown in FIG. 21D, in the amplifier device 3, the output of the content data A stored in the buffer memory is finished at the timing t45 ′, and the content data B is processed by the circuit in the amplifier device 3 and the like. For example, acquisition of the downmix coefficient for the content data B and setting of the acquired coefficient are performed. Then, after the switching process for processing the content data B is performed, when the signal source status command is received from the disc playback device 1 in step S23 ′, the amplifier device 3 is switched to a state of accepting the content data B. A response for notifying this is transmitted to the disc reproducing apparatus 1 (step S24 ').

  Thus, by receiving this response, the disc playback device 1 recognizes that the amplifier device 3 has been switched to a state of accepting the content data B.

  Then, the disc reproducing apparatus 1 stops the mute signal output from the disc reproducing apparatus 1 at this time t35 ′ immediately after receiving the response, and the optical disc 101 of the optical disc 101 is stopped as shown in FIG. The playback pause is released, the playback of the content data B is started, and the output of the content data B is started as shown in FIG.

  The content data B started to be transmitted in this way is input at the timing t46 'in the amplifier device 3, and muted at the timing t47' when some processing time for data processing has elapsed from the timing t46 '. The state is released, and music based on the content data B is output from the speakers 3d and 3e connected to the amplifier device 3.

  As described above, even in a state where the CIP header such as the N flag is changed, complete data transmission and processing can be performed without any missing part such as a head break.

  By the way, in addition to such a configuration, in the case of the present embodiment, the disc playback device 1 formats the content data B to be output next to the amplifier device 3 (content B In order to check whether the amplifier device 3 corresponds to the detected content B format and to receive the content data B in the content B format, the amplifier device 3 In order to confirm whether or not it is possible to configure, the above stream format support status command is sent to the amplifier device 3 (step S201 ′).

  Upon receiving such a stream format support status command from the disc playback device 1 via the bus 9, the amplifier device 3 transmits a response similar to the response in step S102 described above to the disc playback device 1 (step S202 ′). .

  Thus, the disc playback apparatus 1 can recognize whether or not the amplifier apparatus 3 supports the content B format based on the response from the amplifier apparatus 3, and the content data in the content B format in the amplifier apparatus 3. It can be recognized whether or not a plug for receiving B can be configured at present.

  Based on such a response, the disc playback apparatus 1 configures a plug for receiving the content data B in the content B format in the amplifier apparatus 3 that the amplifier apparatus 3 supports the content B format. If the amplifier device 3 recognizes that the content data B can be received, the amplifier device 3 determines that the content data B can be switched to the receiving state for receiving the content data B, and confirms whether or not the switching has been made to the receiving state as described above. Polling processing (steps S21 ′,..., S24 ′) is started.

  On the other hand, the disc playback apparatus 1 indicates that the amplifier apparatus 3 does not support the content B format, or that the amplifier apparatus 3 cannot currently configure a plug for receiving the content data B in the content B format. If recognized, based on this recognition result, the amplifier device 3 determines that it cannot switch to the acceptance state for accepting the content data B, and includes a polling process for confirming whether or not the state has been switched to the acceptance state. The subsequent processing is stopped.

  In this way, the disc playback apparatus 1 can be switched to the receiving state in the first place before confirming with the amplifier apparatus 3 whether or not the switching to the receiving state for receiving the content data B in the content B format is accepted. Whether or not it is confirmed with the amplifier device 3.

(2) Operation and Effect In the above configuration, the disc playback apparatus 1 formats the content data A at the timing T1 when the playback of the content data A recorded on the optical disc 101 ends, for example, as shown in FIG. When it is detected that the format of the content data B to be reproduced is different (step SP1), the reproduction processing for the optical disc 101 is put into a pause state (step SP2), and the amplifier device 3 is in a format different from that of the content data A. The first confirmation process for confirming whether or not it is possible to switch to the acceptance state for accepting the content data B is executed (step SP3).

  Incidentally, the first confirmation process corresponds to a process in which the disc reproducing apparatus 1 transmits a stream format support status command to the amplifier apparatus 3. Further, in the case of the present embodiment, the disc playback apparatus 1 generates data (corresponding to the invalid data described above) in the same format as the content data A instead of transmitting the content data A after the detection in step SP1. The data is transmitted to the amplifier device 3 for a predetermined period, and thereafter, the same format data as the content data B (corresponding to the above-described invalid data, mute signal, etc.) is generated and transmitted to the amplifier device 3. Has been made.

  In response to the first confirmation process, for example, when the amplifier device 3 notifies the disc playback device 1 that it can be switched to an acceptance state for accepting the content data B (step SP4), the disc playback device 1 at this time Then, execution of the second confirmation process for confirming whether or not the amplifier device 3 has been switched to the acceptance state for accepting the content data B is started (step SP5).

  Incidentally, the second confirmation process corresponds to a process in which the disc reproducing apparatus 1 repeatedly transmits an input plug signal format status command to the amplifier apparatus 3.

  When the amplifier device 3 has completely read out the content data A stored in the internal buffer memory (timing T2), the amplifier device 3 changes the setting of the internal circuit and the like by executing a predetermined process, Switch to the acceptance state to accept.

  When switching to the accepting state for accepting the content data B in this way, the amplifier device 3 enters the accepting state for accepting the content data B in accordance with the second confirmation process continued to be executed by the disc reproducing device 1. The disk playback device 1 is notified of the switching (step SP6).

  Receiving this notification, the disc playback apparatus 1 starts to play back the content data B from the optical disc 101 (step SP7), and sequentially transmits the played back content data B to the amplifier device 3 (step SP8). The amplifier device 3 receives the content data B from the disc playback device 1 (step SP9), temporarily stores it in the internal buffer memory, and then sequentially reads the content data B from the buffer memory (step SP10). The music based on this is output from the speakers 3d and 3e.

  On the other hand, when the disc reproducing apparatus 1 recognizes that the amplifier apparatus 3 cannot switch to the receiving state for accepting the content data B based on the notification from the amplifier apparatus 3 in step SP4, the disk reproducing apparatus 1 switches to the receiving state. It is determined that it is useless to confirm whether or not the amplifier device 3 has been switched to the acceptance state, and the second confirmation process (step SP5) for confirming whether or not the amplifier device 3 has been switched to the acceptance state is cancelled. To do. Accordingly, the disc playback apparatus 1 also stops the processing after the second confirmation processing (step SP7,...).

  In this way, the disc reproducing apparatus 1 avoids unnecessary execution of the second confirmation process for confirming whether or not the amplifier apparatus 3 that cannot be switched to the reception state has been switched to the reception state. be able to.

  According to the above configuration, the disc playback apparatus 1 wastefully executes the second confirmation process for confirming whether or not the amplifier apparatus 3 that cannot be switched to the reception state has been switched to the reception state. As a result, the processing efficiency can be significantly improved as compared with the prior art.

  In addition, when the disc reproducing apparatus 1 according to the present embodiment recognizes that the amplifier apparatus 3 cannot switch to the accepting state for accepting the content data B based on the notification from the amplifier apparatus 3 in step SP4, For example, the user is notified via a display unit, a speaker, or the like provided in the disc playback apparatus 1. Thus, the user can recognize that the music based on the content data B cannot be heard because the amplifier device 3 does not correspond to the format of the content data B.

(3) Other Embodiments In the above-described embodiment, when data (invalid data or the like) having the same format as the content data A is transmitted, the first confirmation processing (steps S101, S102, (S101 ′, S102 ′, S201, S202, S201 ′, S202 ′) has been described. However, the present invention is not limited to this. For example, data having the same format as the content data B (invalid data, etc.) During the transmission, the first confirmation process may be executed.

  In the above-described embodiment, audio data (that is, content data) is used as a transmission apparatus that transmits data to a reception apparatus (amplifier apparatus 3) via a communication path established based on a predetermined communication method (IEEE1394). Although the case where the disc playback apparatus 1 that transmits A and content data B) is applied has been described, the present invention is not limited to this, for example, a video playback apparatus such as a video recorder that transmits video data, and other data. Various transmission devices for transmission may be applied.

  Furthermore, in the above-described embodiment, the first confirmation means for executing the first confirmation processing for confirming whether or not the state can be changed to the acceptance state for accepting data (content data B) having the first format. As a second confirmation means for performing a second confirmation process for confirming whether or not a transition to the acceptance state has been performed, a control means, and a detection means for detecting a change from the second format to the first format Although the case where the CPU 110 of the disk reproducing apparatus 1 is applied has been described, the present invention is not limited to this, and an MPU (Micro Processor Unit) or the like may be applied.

  Furthermore, in the above-described embodiment, the case where the bus interface unit 109 of the disc reproducing apparatus 1 is applied as the transmission means for transmitting data to the receiving apparatus has been described. You may make it apply a structure.

  Furthermore, in the above-described embodiment, the first signal transmission means for transmitting to the transmitting device a first response signal indicating that the transition to the acceptance state or the transition to the acceptance state cannot be made, and the transition to the acceptance state Although the case where the CPU 309 and the bus interface unit 308 of the amplifier device 3 are applied as the second signal transmission unit that transmits the second response signal indicating that the state has not been changed to the acceptance state to the transmission device has been described, The present invention is not limited to this, and various other configurations may be applied.

  Further, in the above-described embodiment, the CPU 110 of the disc playback apparatus 1 controls the content data A and the content data B by controlling each circuit unit in the disc playback apparatus 1 according to a transmission program stored in the memory 111 in advance. , Reproduction processing for transmitting the reproduced content data A and content data B to the amplifier device 3, first confirmation processing and second confirmation after detecting a change in the format of the reproduced content data Although the case where the processing is executed has been described, the present invention is not limited to this, and the processing may be realized by hardware.

  Furthermore, in the above-described embodiment, the CPU 309 of the amplifier device 3 determines whether or not it can transit to an acceptance state for accepting the content data B in the content B format according to the signal transmission program stored in the memory 310 in advance. A process of transmitting a first response signal (response) to the disk playback apparatus 1 and a process of transmitting to the disk playback apparatus 1 a second response signal (response) indicating whether or not the state has changed to the acceptance state are executed. However, the present invention is not limited to this, and these processes may be realized by hardware.

  The present invention is a content comprising a disc playback device for playing back an optical disc, and an amplifier device configured to amplify the content data from the disc playback device and then emit music based thereon. It can be used for a data transmission system.

It is a basic diagram which shows the structure of the content data transmission system in this Embodiment. 1 is a schematic diagram illustrating a configuration of a disc playback apparatus. It is a basic diagram which shows the structure of an amplifier apparatus. It is a basic diagram which shows the cycle structure of data transmission. It is a basic diagram which shows the relationship of an isochronous channel. It is a basic diagram which shows the data structure (1) of a packet. It is a basic diagram which shows the data structure (2) of a packet. It is a basic diagram which shows the specific example of an AV / C command. It is a sequence chart which shows a flow control process. It is a basic diagram with which it uses for description of transmission (1) of content data. It is an approximate line figure used for explanation of composition (1) of a command. It is an approximate line figure used for explanation of composition (2) of a command. It is an approximate line figure used for explanation of composition (3) of a command. It is an approximate line figure used for explanation of composition (4) of a command. It is an approximate line figure used for explanation of composition (5) of a command. It is an approximate line figure used for explanation of composition (6) of a command. It is an approximate line figure used for explanation of composition (7) of a command. It is an approximate line figure used for explanation of composition (8) of a command. It is a basic diagram with which it uses for description of transmission (2) of content data. It is a basic diagram with which it uses for description of transmission (3) of content data. It is a basic diagram with which it uses for description of transmission (4) of content data. It is a basic diagram with which it uses for description of a process of a disc reproducing | regenerating apparatus and an amplifier apparatus. It is a basic diagram which shows the example of a connection by the IEEE1394 bus | bath. It is a basic diagram which shows the example from which a format changes. It is a basic diagram which shows the example of rate control. It is a basic diagram which shows the prior art example of transmission of content data.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Disc reproducing apparatus, 3 ... Amplifier apparatus, 9 ... Bus, 110, 309 ... CPU, 109, 308 ... Bus interface part, SYS1 ... Content data transmission system.

Claims (5)

Whether or not the receiving apparatus is capable of communicating via a communication path established based on a predetermined communication method, and whether or not the first apparatus supports the first format, and data for receiving the first format. First confirmation means for performing first confirmation processing for confirming whether or not a plug can be configured;
Second confirmation means for executing second confirmation processing for confirming whether or not the reception apparatus has transitioned to an acceptance state for accepting data in the first format;
When recognizing that the receiving device has transitioned to the accepting state by the second confirmation process, transmitting means for transmitting data in the first format to the receiving device;
Detecting means for detecting that data transmitted by the transmitting means changes from a second format to the first format;
Control means and
The first confirmation means includes
A command for confirming at a time whether or not it is compatible with the first format and whether or not a plug for receiving data in the first format can be configured is transmitted to the receiving device, A plug for receiving a response to the command from the receiving device, and based on the response, whether or not the receiving device is compatible with the first format and receiving data in the first format The process of confirming whether or not can be configured is executed as the first confirmation process,
The control means includes
When the detection means detects that the transmitted data changes from the second format to the first format, after the transmission of the data in the second format is completed, The invalidation data to be transmitted by the transmission means for a predetermined time, and the first confirmation means is controlled to execute the first confirmation processing during the invalid data transmission in the second format,
When the first confirmation process recognizes that the receiving apparatus is compatible with the first format and can constitute a plug for receiving data in the first format, the second format After the transmission of the invalid data is completed, before transmitting the data in the first format, the invalid data in the first format is transmitted by the transmission means, and the second confirmation process is performed. Controlling the second confirmation means to start,
As soon as it is recognized by the first confirmation process that the receiving device does not correspond to the first format or cannot form a plug for receiving data in the first format, the second device A transmitting apparatus for controlling the second confirmation means so as to cancel the confirmation processing and the transmission of invalid data in the first format . The control means includes
When the first confirmation process recognizes that the receiving device does not correspond to the first format or cannot constitute a plug for receiving data in the first format, the second 2. The transmission according to claim 1, wherein the second confirmation unit is controlled so as to cancel the confirmation process, and the user is notified through a predetermined notification unit that the receiving apparatus cannot transition to the acceptance state. apparatus. A detection step of detecting that data to be transmitted to a receiving apparatus capable of communicating via a communication path established based on a predetermined communication method changes from the second format to the first format;
When it is detected in the detection step that the data to be transmitted changes from the second format to the first format, after the transmission of the data in the second format is completed, the data is in the second format. Invalid data is transmitted to the receiving device for a predetermined time, and during the transmission of invalid data in the second format, whether or not the first format is supported for the receiving device, and the first A first confirmation step for executing a first confirmation process for confirming whether or not a plug for receiving data in a format can be configured;
When the first confirmation process recognizes that the receiving apparatus is compatible with the first format and can form a plug for receiving data in the first format, the second format After the transmission of the invalid data is completed, before the data having the first format is transmitted, the invalid data having the first format is transmitted by the transmission unit, and the receiving apparatus A second confirmation process for confirming whether or not a transition to an acceptance state for accepting data in the first format is started, and the receiving apparatus supports the first format by the first confirmation process. If it is recognized that a state for receiving data in the first format cannot be configured, the second confirmation process is immediately performed. And a second verification step to stop the transmission of the invalid data composed of the first format,
If by the second verification process the receiving device recognizes that a transition into the receiving state, comprising a transmission step of transmitting the data composed of the first format to the receiving device,
In the first confirmation step,
A command for confirming at a time whether or not it is compatible with the first format and whether or not a plug for receiving data in the first format can be configured is transmitted to the receiving device, A plug for receiving a response to the command from the receiving device, and based on the response, whether or not the receiving device is compatible with the first format and receiving data in the first format A data transmission method for executing the process of confirming whether or not can be configured as the first confirmation process. In the second confirmation step, the first confirmation process cannot constitute a state for the reception device to receive data not corresponding to the first format or in the first format. The data transmission method according to claim 3 , wherein the second confirmation process is canceled and the user is notified via a predetermined notification means that the receiving apparatus cannot transition to the acceptance state. For a transmission device that transmits data via a communication path established based on a predetermined communication method to the reception device,
A detection step of detecting that data to be transmitted to a receiving apparatus capable of communicating via a communication path established based on a predetermined communication method changes from the second format to the first format;
When it is detected in the detection step that the data to be transmitted changes from the second format to the first format, after the transmission of the data in the second format is completed, the data is in the second format. Invalid data is transmitted to the receiving device for a predetermined time, and during the transmission of invalid data in the second format, whether or not the first format is supported for the receiving device, and the first A first confirmation step for executing a first confirmation process for confirming whether or not a plug for receiving data in a format can be configured;
When the first confirmation process recognizes that the receiving apparatus is compatible with the first format and can form a plug for receiving data in the first format, the second format After the transmission of the invalid data is completed, before the data having the first format is transmitted, the invalid data having the first format is transmitted by the transmission unit, and the receiving apparatus A second confirmation process for confirming whether or not a transition to an acceptance state for accepting data in the first format is started, and the receiving apparatus supports the first format by the first confirmation process. If it is recognized that a state for receiving data in the first format cannot be configured, the second confirmation process is immediately performed. And a second verification step to stop the transmission of the invalid data composed of the first format,
When the second confirmation process recognizes that the receiving device has transitioned to the acceptance state, a transmission step of transmitting data in the first format to the receiving device is executed.
In the first confirmation step,
A command for confirming at a time whether or not it is compatible with the first format and whether or not a plug for receiving data in the first format can be configured is transmitted to the receiving device, A plug for receiving a response to the command from the receiving device, and based on the response, whether or not the receiving device is compatible with the first format and receiving data in the first format A data transmission program for executing the process of confirming whether or not the above can be configured as the first confirmation process.

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