Display system and display apparatus

If a device non-compatible with CEC is contained in an input path when a display apparatus is HDMI-connected hierarchically to a plurality of external devices, an external device which has transmitted <Active Source> is selected as an operation object device. A TV (100) is HDMI-connected hierarchically to external devices (an AV amplifier (20a), recorders (10a, 10c), a DVD player (10b)) in a tree shape. The TV (100) receives <Active Source> indicating an active state capable of video output from the DVD player (10b) and transmits <Set Stream Path> for switching the input path to the DVD player (10b). When a device non-compatible with CEC (AV amplifier (20a)) is contained in the input path which transmits <Set Stream Path>, the TV (100) selects the DVD player (10b) specified <Active Source> as an operation object device.

TECHNICAL FIELD

The present invention relates to a display system and a display apparatus, more specifically, to a display system including a display apparatus capable of being connected to an output apparatus (external device) such as a DVD recording apparatus through a digital interface such as an HDMI (High Definition Multimedia Interface) and a display apparatus constituting the system.

BACKGROUND OF THE INVENTION

HDMIs have come into wide use as a digital interface for transmission of video/audio. The HDMI is arranged for AV devices by adding an audio transmission function and a copyright protection function to DVI which is a connection standard for a PC and a display.

Conventionally, a plurality of cables for each signal of video/audio/control have been used for the connection between devices, however, since the HDMI needs only one cable and control signals correspond to bidirectional transmission, it has also been possible to operate the entire AV system such as a home theater with one remote controller by relaying the control signal to an output apparatus such as an STB (Set Top Box) and a DVD player connected by the HDMI from a monitor.

The basic specification for the standard of the HDMI was established in December 2002 by the standardization organization of HDMI Licensing, LLC (HDMI standard Ver1.0), and a rule for CEC (Consumer Electronics Control) was added as a control protocol for performing control between AV devices in December 2005 (HDMI standard Ver1.2a, refer to Non-Patent Literature 1). After that, although some revisions have been made, description of the CEC will hereinafter be based on the standard after the HDMI standard Ver1.2a and be referred to as the HDMI standard unless otherwise noted.

Note that, terms about the CEC are defined in “2.2 Glossary of Terms” of the HDMI standard, “CEC 2.2 Glossary of Terms” and the like, where one that has an HDMI input terminal is defined as a sink device, one that has an HDMI output terminal and outputs an AV stream is defined as a source device, and one that has an HDMI input terminal and output terminal and inputs/outputs an AV stream is defined as a repeater device.

In the HDMI standard, control between devices using the CEC is defined. According to the CEC, various kinds of control are possible based on individual physical addresses and logical addresses assigned to each device existing on an HDMI network. For example, when reproduction of video is made by depressing a reproduction button, or the like, of a DVD player connected by HDMI while a user views digital broadcast on a television, the television automatically switches to an input connected with the DVD player. Moreover, operation menu displayed on the DVD player, on/off of a power source and the like is able to be operated from a remote controller of the television.

In addition, the HDMI standard prescribes that operation is able to be made even when a maximum of 10 devices including a television are connected, thus it is possible to connect up to nine external devices to a television. When one device compatible with HDMI CEC is connected to the television, it is clear which device is operated from a remote controller, however, when a plurality of devices compatible with HDMI CEC are connected, there is a problem that it is hard to recognize which device is operated from the television using a remote controller of the television.

Hence, it is considered that, when operating of the device compatible with HDMI CEC from the television using the remote controller of the television as described above, by selecting a device actually displaying video on the television as a device targeted for the operation, the operation object device is limited from a plurality of devices. In the HDMI standard, as a CEC message for clearly indicating such a device displaying video on the television, <Active Source> is prescribed. According to this prescription, for example, in a case where a user operates a reproduction button of a DVD player compliant with HDMI CEC, when the DVD player itself is in a state capable of outputting stable video signal (that is, in an active state), the DVD player outputs an AV stream as well as broadcasts <Active Source> indicative of being an active device. Here, the “broadcast” means simultaneous transmission of signal whose transmission destination is not a specific device but all devices. The television and other devices compatible with HDMI CEC to which <Active Source> has been broadcasted switch a route for reproducing the AV stream output from the DVD player. In this way, it is prescribed that in devices compatible with HDMI CEC a device displaying video on TV broadcasts <Active Source> to other devices in a network.

Note that, although an example in a case of operating a reproduction button of a DVD player has been described above, it is similar in the next case. For example, in a case where <Request Active Source> has been broadcasted by other device compatible with HDMI CEC due to a user operation, and when a DVD player is an “active device”, the DVD player broadcasts <Active Source> indicative of itself being an active device. Here, the <Request Active Source> is one of CEC messages defined in the HDMI standard and used for a purpose to inquire about an active device in a route.

However, a method in which an “active device” which has broadcasted <Active Source> becomes as an operation object device has the following problem. To correspond to the CEC itself is optional in the HDMI standard, however, essentially corresponded prescriptions and selectively corresponded prescriptions are mixed in various prescriptions of the CEC, thus posing the following disadvantage.

Assumed is a state where a television includes a plurality of HDMI input terminals, and for example, a device A and a device B that are devices compatible with HDMI CEC are connected to each of the HDMI input terminals. First, it is assumed that a user operates a reproduction button of the device A intending to operate the device A connected to the television. In this case, since the device A is an operable device, the device A broadcasts <Active Source> as described above. That is, at this time, the television and other devices compatible with HDMI CEC having received this are notified that the device A is an “active device”.

Next, it is assumed that the user performs input switching operation of the television intending to operate the device B and selects a connected input of the device B. However, there is a case where the device B does not broadcast <Active Source>, and in such a case, the device A remains as an “active device”. Thus, even when the user performs some operation to the device B, operation signal thereof is transmitted to the device A which is the “active device”. Such disadvantage is caused by that the device B does not correspond to a selectively-corresponded prescription in the HDMI standard.

Even after a user displays video to instruct switching to a device desired to be an operation object, when the switching destination device is not an “active device”, the television does not recognize the device as an operation object device, thus it is impossible to operate the switching destination device from the television.

Contrary to this, even when a device is not an “active device”, there is a method that the television recognizes the device as an operation object device. This method is, regardless of presence/absence of <Active Source>, one in which a device specified by <Set Stream Path> becomes as an operation object device. The <Set Stream Path> is one of CEC messages defined in the HDMI standard, and when an input switching operation is made by a user, transmitted from a television to switch an input path by broadcast.[Non-Patent Literature 1] High-Definition Multimedia Interface Specification Version 1.2a Supplement 1 Consumer Electronics Control (CEC), Dec. 14, 2005

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, the above-described method in which the device specified by <Set Stream Path> becomes as an operation object device has the following problem.

For example, it is assumed that a television, a repeater device and a source device are connected in this order and the repeater device is a device non-compatible with CEC. In a case where video output operation is made to the source device or <Request Active Source> is broadcasted by other device compatible with HDMI CEC, the source device, when being an “active device” in itself, broadcasts <Active Source>. A television having received <Active Source> broadcasts <Set Stream Path> to switch an input path to the source device. At this time, since the repeater device which is a device non-compatible with CEC does not notify the television of a physical address of a source device connected to the repeater device itself, the television is able to recognize only up to the physical address of the repeater device. As a result, the television broadcasts <Set Stream Path> that specifies the physical address of the repeater device. Thereby, in the case of making the device specified by <Set Stream Path> become as an operation object device, the repeater device which is a device non-compatible with CEC is to be recognized as the operation object device.

The present invention has been made in view of the above-mentioned circumstances, and an object is to provide a display system capable of, in a case where a plurality of external devices are HDMI-connected to a display apparatus hierarchically and a device non-compatible with CEC is contained in an input path, selecting an external device that has transmitted <Active Source> as the operation object device without selecting an operation object device by <Set Stream Path> and a display apparatus constituting the system.

Means for Solving the Problems

In order to solve the above problem, a first technical means of the present invention is a display system wherein a display apparatus and a plurality of external devices are HDMI-connected hierarchically in a tree shape, wherein the display apparatus is provided with a CEC interface which receives a first CEC message indicative of being in an active state capable of outputting video, from any of external device out of the plurality of external devices, and which transmits a second CEC message to switch an input path to the external device, and operation object device selection portion for selecting, when a device non-compatible with CEC is contained in the input path for transmitting the second CEC message, an external device that corresponds to a physical address specified by the first CEC message as an operation object device.

A second technical means is the display system as defined in the first technical means, wherein the operation object device selection portion compares a first physical address contained in the first CEC message received from the external device, with a second physical address contained in the second CEC message transmitted from the display apparatus, and when an input path shown by the second physical address is contained in an input path shown by the first physical address, an external device that corresponds to a physical address specified by the first CEC message is selected as an operation object device.

A third technical means is the display system as defined in the first technical means, wherein the operation object device selection portion selects an external device specified by the second CEC message as an operation object device when a device non-compatible with CEC is not contained in the input path for transmitting the second CEC message.

A fourth technical means is the display system as defined in any one of the first through the third technical means, wherein the first CEC message is <Active Source> defined in HDMI standard, and the second CEC message is <Set Stream Path> defined in the HDMI standard.

A fifth technical means is the display apparatus constitutes the display system as defined in any one of the first through the third technical means.

Effect of the Invention

According to the present invention, in a case where a plurality of external devices are HDMI-connected to a display apparatus hierarchically and when a device non-compatible with CEC is contained in an input path, without selecting an operation object device by <Set Stream Path>, selecting an external device that has transmitted <Active Source> as the operation object device is possible, and thereby a user may operate the connected external device smoothly without particular consciousness about device compatible/non-compatible with HDMI CEC.

EXPLANATION OF REFERENCE NUMERALS

PREFERRED EMBODIMENT OF THE INVENTION

Preferred embodiments according to a display system and a display apparatus constituting the system of the present invention will hereinafter be described with reference to the accompanying drawings.

In the embodiments of the present invention, a CEC message included in the HDMI standard is used. The CEC message is device control signal standardized by the HDMI.

FIG. 1is a block diagram illustrating a structural example of important parts according to HDMI connection in the display system of the present invention, which shows the structure in which a source device10, a repeater device20and a sink device30are connected through an HDMI cable. Note that, the source device10is, for example, such as a DVD recorder, an HDD recorder, a DVD player, a digital system VTR, and a digital video camera, each of which has an HDMI output terminal. The repeater device20such as an AV amplifier, a recorder, and a player, each of which has HDMI input terminal and output terminal. The sink device30is a display apparatus including a liquid crystal television and a monitor, each of which has an HDMI input terminal. When the repeater device20such as an AV amplifier has a plurality of HDMI input terminals, a plurality of the source devices10can be connected to the repeater device20and an input line can be switched using a selector function of the AV amplifier.

The sink device30according to the present invention detects operation states of the repeater device20and the source device10, and uses a CEC message transferred through a CEC line42to control the operation states of the repeater device20and the source device10. As has been described above, the CEC message is device control signal based on a CEC protocol of the HDMI standard. In addition, by exchanging the device control signal between devices, various operation controls are realized between the sink device30and a connected device.

Note that, the HDMI cable includes a TMDS (Transition Minimized Differential Signaling) line (digital signal line)41for transmitting video/audio signal as digital signal in a differential method and the CEC line42which is a bidirectional bus for transmitting common control signal (CEC message) between devices. In addition, the HDMI cable includes a DDC (Display Data Channel) line (not shown) which is used for transmission of EDID (Extended Display Identification Data), authentication of HDCP (High-bandwidth Digital Content Protection system) and the like.

Description will hereinafter be given for a structure of important parts according to HDMI connection of the source device10, the repeater device20, and the sink device30.

The source device10includes an HDMI transmitter11, a HOST CPU12, a front microcomputer13, and a CEC interface (hereinafter, CEC I/F)14. The HDMI transmitter11reads video data and audio data recorded on a medium such as a DVD, for example, to convert into an AV stream in an HDMI format, in which audio signal is inserted in a blanking period of video signal. Then, the converted AV stream is transferred to the repeater device20through the TMDS line41by the HDMI transmitter11. The HOST CPU12includes an HDMI controller for controlling operation of the HDMI transmitter11.

The CEC I/F14is connected to the CEC line42in the HDMI cable and allows bidirectional communication of a CEC message with the repeater device20. The CEC I/F14is controlled by the front microcomputer13including a CEC controller so that HDMI-connected devices can be controlled using the CEC message. In the case of the CEC, logical address (type of device) and physical address (position of device) of each HDMI-connected device are obtained, and therefore it is possible to transmit the CEC message to a desired device by specifying the physical address.

The HOST CPU12controls the entire apparatus. Moreover, the front microcomputer13operates with low electric power and always monitors a CEC message transferred from the CEC line42. In addition, when there is a remote controller, the presence/absence of transmission of remote controller signal thereof is monitored. Moreover, even when the power source of the HOST CPU12is cut because of a stand-by mode of the apparatus and the like, the front microcomputer13operates (operates in a state capable of at least transferring a CEC message).

The repeater device20includes an HDMI receiver21, an HDMI transmitter22, a HOST CPU23, a front microcomputer24, and a CEC I/F25. The repeater device20receives an AV stream transferred from the source device10at the HDMI receiver21and further transmits the AV stream to the sink device30from the HDMI transmitter22. In addition, the CEC line42between the repeater device20and the source device10and the CEC line42between the repeater device20and the sink device30are connected by the CEC I/F25.

The HOST CPU23and the front microcomputer24have the similar function to that of the above-mentioned source device10, and the HOST CPU23controls the HDMI receiver21and the HDMI transmitter22as well as controls the entire apparatus. In addition, the front microcomputer24includes a CEC controller for monitoring a CEC message transferred from the CEC line42.

The sink device30includes a HOST CPU31containing an HDMI receiver, a front microcomputer32, a CEC I/F33, a memory34, and a light receiving portion35. The sink device30receives the AV stream transferred by the repeater device20at the HOST CPU31containing the HDMI receiver. The HDMI receiver may be separated from the HOST CPU31. In addition, with the CEC I/F33, the CEC line42between the sink device30and the repeater device20is connected. A control program of the sink device30and the like are stored in the memory34. In addition, the memory34stores physical addresses of the repeater device20and the source device10that are HDMI-connected to the sink device30based on the HDMI standard.

The HOST CPU31contains the HDMI receiver and controls the entire apparatus. Moreover, the front microcomputer32includes a CEC controller for monitoring a CEC message transferred from the CEC line42. The front microcomputer32controls the light receiving portion35for receiving remote controller signal from the remote controller36. In addition, even when the power source of the HOST CPU31is cut because of a stand-by mode of the apparatus and the like, the front microcomputer32operates to maintain a state capable of transmitting/receiving a CEC message and receiving remote controller signal.

FIG. 2is a block diagram showing a structural example of the display apparatus according to an embodiment of the present invention, and shows an example where the display apparatus of the present invention is applied to a television apparatus. In the figure,100denotes a television apparatus which has an HDMI CEC function similar to that of the sink device30shown inFIG. 1.

The television apparatus100includes a TV tuner101for selecting and demodulating television broadcast signal, a demultiplexer102for extracting EPG (registered trademark) data from demodulated broadcast signal and separating the demodulated data, and a decoder103for decoding separated video signals and audio signals of digital broadcast.

Moreover, the television apparatus100has a system control portion104for performing control of the entire system, and a bus control portion105for granting permission of using a bus in response to a request of using bus from the system control portion104. When there is a request of using bus at one time, the bus control portion105promptly grants permission to use the bus, and when there are a plurality of requests at one time, that is, when requests of using bus compete with each other, permission of using bus is granted according to priority previously determined by the system control portion104and the like.

The television apparatus100is provided with two external input terminals106and107(external input terminals1and2), and two HDMI terminals108and109(HDMI terminals1and2). An input switching menu is prepared in order to switch the external input terminals106and107and the HDMI terminals108and109, and is held in a memory115. The memory115is a nonvolatile memory or the like, and stores a control program for operating the television apparatus100and various kinds of data. The external input terminals106and107are terminals for external input except for HDMI input, and are interfaces of, for example, such as a video input terminal, IEEE 1394, and USB (registered trademark). The HDMI terminals108and109, including CEC I/F shown inFIG. 1, connect a plurality of external devices through an HDMI cable for transmitting/receiving a CEC message between external devices by a CEC line as well as receiving video signal (including audio signal) from external devices by a TMDS line.

In an image processing portion110, video signal converting processing such as noise reduction, scaling, and IP conversion, is appropriately performed as the occasion demands. In addition, image quality adjustment such as image quality emphasis correcting processing and γ correcting processing is appropriately performed. Moreover, in image signal converting processing, a frame memory112is used to perform various kinds of three-dimensional image processing. A device driving portion111controls driving of a display apparatus113such as a liquid crystal panel to cause the display apparatus113to display video signals output from the image processing portion110. In addition, the television apparatus100is provided with an infrared ray receiving portion114for receiving infrared ray signal from a remote controller (not shown) operated by a user.

Further, audio signal decoded by the decoder103is processed at an audio processing portion116and this audio signal is supplied to a speaker117to reproduce sound.

The system control portion104includes the front microcomputer shown inFIG. 1and the like, and controls input switching of the TV tuner101, the external input terminals106and107, and the HDMI terminals108and109. In addition, the system control portion104performs analysis of a CEC message transmitted/received through the HDMI terminals108and109and control of operations based on the analysis result.

A main characteristic part of the present invention lies in that, in a case where a plurality of external devices are connected to the television apparatus100through the HDMI terminals108and109hierarchically in a tree shape and a device non-compatible with CEC is contained in an input path, selecting an external device that has transmitted <Active Source> as an operation object device is performed without selecting an operation object device by <Set Stream Path>. As the structure for this, the television apparatus100includes the HDMI terminals (CEC I/F)108and109which receive <Active Source> corresponding to the first CEC message indicative of being in an active state and output from any external device out of a plurality of external devices, and transmit <Set Stream Path> corresponding to the second CEC message for switching an input path to the external device. The <Active Source> is transmitted from an external device that has become an “active device” as video output operation was made by a user, or an external device which has been an “active device” when <Request Active Source> was broadcasted from other device compatible with HDMI CEC by a user operation.

Furthermore, the television apparatus100includes, when a device non-compatible with CEC is contained in an input path for transmitting <Set Stream Path>, operation object device selection portion104afor selecting an external device specified by <Active Source> as an operation object device. The operation object device selection portion104aselects, when a CEC non-corresponding apparatus is not contained in the input path for transmitting <Set Stream Path>, an external device specified by <Set Stream Path> as the operation object device. The function of the operation object device selection portion104ais executed by the system control portion104.

Description will be given for a method for selecting an operation object device by a display system of the present invention with reference toFIGS. 3 and 4below illustrating a specific example.

FIG. 3is a view illustrating an example of a method for selecting an operation object device by the display system of the present invention. In this example, the television apparatus (hereinafter, TV)100as a sink device includes two HDMI inputs (input1and input2), wherein one input1is connected to an AV amplifier20aas a repeater device, and further the AV amplifier20aincludes two HDMI inputs (input3and input4), wherein the input3is connected to a recorder10aas a source device and the input4is connected to a DVD player10bas a source device. Additionally, the other input2is connected to a recorder10cas a source device. Note that, numbers of (0.0.0.0), (1.0.0.0), . . . , (2.0.0.0) assigned to each device are physical addresses showing connected positions of each device.

FIG. 4is a view showing an example of communication processing by CEC when input switching is performed by video output from a source device.FIG. 4(A)shows an example of a case where the AV amplifier20aas the repeater device is a device compatible with HDMI CEC, andFIG. 4(B)shows an example of a case where the AV amplifier20aas the repeater device is a device non-compatible with CEC. Note that, description for the communication processing inFIGS. 4(A)and (B) will be given based on the connection example ofFIG. 3, and a command transmission illustrated by a dotted line shows processing of transmitting from a transmission source by broadcast.

InFIG. 4(A), when a reproduction button of a DVD player10bat physical address (1.2.0.0) is pressed and reproduction of AV stream is started during the viewing video recorded in a recorder10con TV100, the DVD player10btransmits <Active Source> indicative of itself being an “active device” by broadcast (S11). On receipt of this, TV100transmits a CEC message <Routing Change> indicative of switching an input path to HDMI input (input1) to which the AV amplifier20ais connected, by broadcast (S12). Then, on receipt of this, the AV amplifier20atransmits, as the DVD player10bis connected thereto, a CEC message <Routing Information> to notify of an input path from the AV amplifier20ato the DVD player10bby broadcast (S13). Finally, the TV100having received this transmits a CEC message <Set Stream Path (1.2.0.0)> to determine the input path to the DVD player10bby broadcast (S14).

At the physical address (1.2.0.0) specified by the finally transmitted <Set Stream Path>, the DVD player10bexists. Accordingly, an operation object device in this case is the DVD player10b. Note that, in this case, the physical address (1.2.0.0) is the second physical address.

Hereinbefore, description has been given illustrating a case where the reproduction button of the DVD player10bwas pressed, however, it is also similar in a case where <Request Active Source> is broadcasted from other device compatible with HDMI CEC due to a user operation, and a DVD player10bbroadcasts <Active Source> indicative of itself being an “active device”.

Here, both the <Routing Change> and <Routing Information> are CEC messages defined in the HDMI standard. The <Routing Change> is for showing a change of the input path, and the <Routing Information> is for notifying of the input path on receipt of the <Routing Change>.

According to the example ofFIG. 4(A), in response to the video output operation for the source device, <Active Source> is transmitted from the source device. The TV on receipt of this transmits <Set Stream Path> by broadcast specifying a physical address of the source device. As a result, the source device specified by <Set Stream Path> may become as an operation object device. In this case, the AV amplifier20aas the repeater device needs to be a device compatible with HDMI CEC.

However, when the AV amplifier20ais a device non-compatible with CEC, because of not reacting to <Routing Change> broadcast-transmitted by the TV100, the CEC message <Routing Information> to notify of the input path from the AV amplifier20ato the DVD player10bis not transmitted. Thereby, <Set Stream Path> finally transmitted by the TV100is to be <Set Stream Path (1.0.0.0)> which input path has been confirmed. Accordingly, the AV amplifier20ais selected as an operation object, and the DVD player10bis not able to become as an operation object. Description for this will be given based onFIG. 4(B).

InFIG. 4(B), when a reproduction button of a DVD player10bat physical address (1.2.0.0) is pressed and reproduction of AV stream is started during the viewing video recorded in a recorder10con TV100, the DVD player10btransmits <Active Source> indicative of itself being an “active device” by broadcast (S21). On receipt of this, TV100transmits a CEC message <Routing Change> indicative of switching an input to HDMI input (input1) to which an AV amplifier20ais connected, by broadcast (S22). However, since the AV amplifier20ais a device non-compatible with CEC that does not respond to a CEC message, a CEC message <Routing Information> to notify of a route from the AV amplifier20ato the DVD player10bis not transmitted.

Then, the TV100which is not able to receive <Routing Information>, is unable to determine an input path from and after the AV amplifier20a, and transmits a CEC message <Set Stream Path (1.0.0.0)> to determine a finally confirmed input path up to the AV amplifier20aby broadcast (S23).

As a result, at a physical address specified by <Set Stream Path> finally transmitted, the AV amplifier20aexists, and the AV amplifier20athat is a device non-compatible with CEC becomes an operation object device.

To improve such a problem, processing described below is executed in the present invention.

The TV100recognizes that the “active device” is the DVD player10bat the time <Active Source> has been transmitted (S21). Therefore, the TV100updates, at the time of receiving the <Active Source>, an operation object device (that is, updates to the DVD player10b) with the physical address (first physical address) notified by the <Active Source>. Furthermore, in route switching processing on receipt of <Active Source>, as long as the physical address (second physical address) specified by <Set Stream Path> transmitted in the processing is a device non-compatible with CEC, an operation object device is not to be updated by the physical address (second physical address) of the device non-compatible with CEC. Thereby, in the case of the example ofFIG. 3, the AV amplifier20athat does not correspond to CEC is not selected as an operation object, and the DVD player10bspecified by <Active Source> is selected as an operation object device.

Note that, the above-described processing is executed only in a case where the AV amplifier20ais the device non-compatible with CEC, and when the AV amplifier20ais the device compatible with HDMI CEC, as shown inFIG. 4(A), an operation object device is updated by the physical address specified by the <Set Stream Path>.

Update processing of an operation object device when the AV amplifier20adoes not correspond to CEC, or corresponds to CEC, is executed by operation object device selection portion104ashown inFIG. 2. The operation object device selection portion104ais able to determine whether AV amplifier20ais device compatible with HDMI CEC or non-corresponding device by presence/absence of a response to a CEC message <Routing Change>.

Here, a physical address of the AV amplifier20ais (1.0.0.0) and a physical address of the DVD player10bis (1.2.0.0), therefore it is understood that an input path up to the physical address (1.0.0.0) of the AV amplifier20ais contained in an input path up to the physical address (1.2.0.0) of the DVD player10b. Nonetheless, since there is no response to a CEC message from the AV amplifier20aat the physical address (1.0.0.0), it is recognized that it is a device non-compatible with CEC. In the case of the device non-compatible with CEC, because of not responding to a CEC message, the physical address (1.0.0.0) of the AV amplifier20ais not appropriate as a physical address of an operation object device. Thereby, an operation object device is not updated by the physical address (1.0.0.0) of the AV amplifier20a, and the DVD player10bat the physical address (1.2.0.0) specified by <Active Source> that has already been received, becomes as an operation object device. Note that, in this case, the physical address (1.2.0.0) is the first physical address.

That is, the operation object device selection portion104ashown inFIG. 2compares the first physical address (1.2.0.0) included in the <Active Source> received from the DVD player10b, with the second physical address (1.0.0.0) included in the <Set Stream Path> transmitted from the TV100, and when an input path shown by the second physical address (1.0.0.0) is contained in an input path shown by the first physical address (1.2.0.0), the DVD player10bspecified by <Active Source> is selected as an operation object device.

By performing the above-described processing, in a network structure to which a plurality of devices are HDMI-connected, even when a CEC non-corresponding repeater device exists between a sink device (TV) and a source device, the source device notifies TV of <Active Source> by performing video output operation to a source device and, thereby, the source device that has notified of the <Active Source> is able to become as an operation object.