Display system, display device, and repeater

Also in a video system in which a device responding to a multiple screen display function and a non-responding device are mixedly present, a communication message for a collaboration of the device which performs a multiple screen display operation is realized without exerting an influence on operations of the non-responding device. A video device including two or more video input ports and capable of simultaneously receiving videos output from multiple video source devices connected to the video input ports is configured so as to perform a predetermined filtering operation or message conversion when transmitting to the other video input ports a communication message for video device control to be converted through the video input ports.

INCORPORATION BY REFERENCE

The present application claims priority from Japanese application JP2010-198460 filed on Sep. 6, 2010, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

The present invention relates to transmission and reception of a video signal.

As an interface for transmitting a video signal from a source device to a display device, a High-Definition Multimedia Interface (HDMI. A trademark of HDMI, LLC) is widely used. Further, a collaboration operation between a source device and a display device is realized based on a control communication such as Consumer Electronics Control (CEC) included in the HDMI.

In JP-A-2008-109342, the following technique is disclosed. A display device is provided with an HDMI input port. External equipment including an Nil output port can be directly connected to the HDMI input port by an HDMI cable. Further, external equipment can be connected to the display device also through relay external equipment including HDMI input and output ports. The display device includes a multiple screen display control means for performing control for simultaneously displaying each of the input images from two or more input sources on a screen and a command detection means for detecting a prescribed screen start command showing the output of the setting screen image of the external equipment transmitted by using a CEC command based on an HDMI specification from the external equipment connected to the display device. The multiple screen display control means performs control for additionally displaying the setting screen image output from the external equipment on a sub-screen when detecting the screen start command by the command detection means. In addition, an AV amplifier2combines videos into a two-screen mode and outputs it to a television device1.

Also, in JP-A-2010-102053, the following technique is disclosed. It is an object of the present invention to provide a video generation device and a video display device capable of displaying the videos of two screens which make a video already displayed in a video display device, such as a broadcasting signal as a main-screen image and a video newly generated in the external part as a sub-screen video, on a one-screen with automatically and optically designed layout, without changing the structure of the inner part of a display device. Further, as a layout command of specifying each display position (coordinate value of upper left) of a main-screen video and a sub-screen video and a display size, a command of switching an input over to a terminal to which a command referred to <active source> in an HDMICEC is input is used, and further is expanded as inFIG. 3.

SUMMARY OF THE INVENTION

However, in the above-described prior art documents, the control of using an existing command specified by the HDMI is not taken into consideration. As a result, the devices disclosed in the above-described prior art documents are hard to be used in an existing system, and therefore, are not user-friendly.

To solve the above-described problem, for example, a configuration described in a patent claim is adopted.

According to an aspect of the present invention, there is provided a display system. This display system includes a first source device to output a first video signal; a second source device to output a second video signal; and a display device connected to the first and second source devices, wherein at a time when the display device displays the first video signal, when a message for starting an output of the second video signal is transmitted from the second source device to the display device, the display device displays the first and second video signals; and when changing from one state of displaying the first and second video signals to another state of displaying the second video signal, the display device transfers to the first source device a message for starting the output of the second video signal received from the second source device.

According to the above-described method, display of multiple videos can be realized by using an existing system, and user-friendly devices can be provided.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

FIG. 1is an example where two video signals output two source devices12and13are displayed on two screens by using a display device40. A remote control41is an input tool for controlling the display device or source devices and inputting an instruction by a user.

FIG. 2is a block diagram illustrating a configuration example of the display device40illustrated inFIG. 1. An electric wave of television broadcasting received by a broadcast receiving antenna409is supplied to a broadcast receiving processing unit410, and a broadcast signal of a channel desired by the user is extracted. Further, the broadcast signal is frequency-converted into a predetermined frequency band and is demodulated so as to release a modulation process performed for transmission on the broadcast station side.

In the case of digital broadcasting, two or more contents are time-division multiplexed into one broadcast channel in many cases. Further, the broadcast receiving processing unit410performs a predetermined process such as a demultiplexing process for selecting contents desired by the user.

An output signal from the broadcast receiving processing unit410is supplied to an audio visual processing unit413. Here, the broadcast receiving processing unit410may perform simultaneous decoding processing of two or more contents time-division multiplexed or simultaneous demodulation of two or more broadcast channels to supply an output signal of the two or more contents to the audio visual processing unit413at the same time.

On the other hand, an HDMI receiver411decodes video signals produced from the source devices (not illustrated) connected to two or more video input ports such as HDMI terminals401,402, and403, and supplies them to the audio visual processing unit413. The HDMI receiver411has a function of supplying two or more video signals to the audio visual processing unit413at the same time.

The audio visual processing unit413selects output signals from the broadcast receiving processing unit410and the HDMI receiver411, or combines multiple screens. At the same time, if necessary, the audio visual processing unit413supplies to a display unit415the video signal to which a high definition process is performed, and the display unit415displays videos. Further, the audio visual processing unit413supplies an audio signal added to the supplied video signal to a speaker416, and the speaker416reproduces a voice.

A CEC controller412exchanges messages for performing a collaboration operation with the source devices (not illustrated) connected to the HDMI terminals401,402, and403through CEC lines within HDMI cables. In the HDMI specifications, the CEC lines the same video system are commonly-connected; further, the display device having a physical address of [0000] causes the CEC line of each HDMI terminal to go independent.

In an usual video system with CEC, only one source device is allowed to output a video signal. When each CEC line that connect to each HDMI terminal is not connected in the display device, each HDMI terminal can control each source device independently. Therefore, video signals from two or more source devices are simultaneously received by the HDMI receiver411, and videos are combined by the audio visual processing unit413, thereby realizing a two-screen display mode as illustrated inFIG. 1by using the display unit415. In addition, the controller414controls all of these operations of the display device40.

As can be seen from the above sequence, when the CEC lines are caused to go independent, two or more video signals and audio signals can be simultaneously received to realize a multiple-screen display mode. In addition, two or more audio amplifiers can be connected to individually perform a collaboration operation; however, in the HDMI video system, only one audio amplifier is allowed to be connected. However, when messages fail to be exchanged between the independent CEC lines, the collaboration operation between the video devices is considered to be disturbed.

To cope with the above problem the CEC controller412may transfer messages by a procedure as illustrated in a flowchart ofFIG. 3. This is referred to as a filtering process. Hereinafter, each step of this filtering process will be described according to the flowchart.

(S701) To source devices (not illustrated) connected to each of the HDMI terminals401,402, and403, the physical addresses of [1000], [2000], and [3000] are given, respectively, according to specifications determined in the HDMI. When each source device is further connected to other source devices, the physical address of [1xxx] [2xxx] and [3xxx] are given to them, respectively. When viewing a first figure of the physical address, which source device is connected to which HDMI terminal can be distinguished.

On the other hand, in a header of the CEC message, a logical address of 4-bit is written as a destination, and an association table between the logical address and the physical address is previously stored. Therefore, this permits the CEC controller412to determine which message is transferred to a device connected to which HDMI terminal.

When the message is transferred to a device connected to another HDMI terminal different from the received HDMI terminal, the process proceeds to step S702.

The CEC message is treated as a broadcast message when it is a message (e.g., having the logical address of “F”) to all the devices connected through the HDMI terminal, and the process then proceeds to step S706.

When the CEC message is a message to a device (including its own device) connected to the received HDMI terminal, or a message a destination of which is not included in the association table, the CEC controller412determines that it is a message to the other destinations, and then this filtering process ends. When its own device is used as a destination, this filtering process ends. Then, ACK (ACKnowledge, an affirmative message transmitted to a transmission source from a transmission destination of the data) for transmission confirmation is sent back as the original CEC reception process, and a predetermined response operation is performed.

(S702) Judging from a header, when the CEC message is a message to a device connected to another HDMI terminal, ACK is sent back in place of the destination device.

(S703) When the ACK can be normally sent back by proxy and the ACKs from other devices fail to be detected, the process proceeds to step S705. On the other hand, when the ACK responses from other devices are detected, the association table between the logical address and the physical address is considered to be wrong. Therefore, the CEC controller412cancels an ACK replay, and the process proceeds to step S704.

(S704) After the CEC controller412deletes the relevant logical address from the association table, this filtering process ends. Before deleting the logical address, a polling message is sent to the logical address. After whether devices having different physical addresses respond by the same logical address is confirmed, the logical address may be deleted. If the ACKs are confirmed from both of the devices connected to the different HDMI terminals by the same logical address, the logical address is double registered. Therefore, the logical address of either one of the two devices is changed. Alternatively, new logical addresses are acquired by proxy by the HDMI terminals, respectively, and they may be added to the above-described conversion table including conversion to the new logical address.

(S705) The CEC controller412transfers the CEC message to the CEC line of the HDMI terminal to which the destination device is connected, and the process ends. When an ACK fails to be sent back during the message transfer, the CEC controller412may determine that the device leaves a video system and delete it from among the association table between the logical address and the physical address. Before deleting the device from the above-described table, the CEC controller412may send a polling message to it, and again confirm whether it is present. Then, the CEC controller412may delete the device from the association table.

(S706) When determining based on the header that the CEC message is a broadcast message, the CEC controller412determines based on a subsequent operation code whether the CEC message is a message to be transferred. If the CEC message is transferred, the process proceeds to step S707. If the CEC message is not required to be transferred, the filtering process ends. If the multiple-screen display mode is not performed, all the CEC messages are to be transferred. If the multiple-screen display mode is performed, the CEC controller412stop to transfer the CEC message to the HDMI terminal in which a message on a transmission route change of video signals, such as <Active Source>, <Routing Information>, <Routing Change>, and <Set Stream Path> is selected as an input source of the multiple-screen display mode.

The reason is that the source device during providing a video for the multiple-screen display mode is prevented from stopping a video signal. An influence is not exerted on the multiple-screen display mode with respect to the source device which fails to provide a video for the multiple-screen display mode, and therefore, the CEC controller412may transfer the CEC message to it.

(S707) By using broadcast, the CEC controller412transfers the CEC message to the devices connected to the other HDMI terminals, and the filtering process ends.

According to the above-described process, without defining a new CEC message, while a device having two or more HDMI terminals such as the display device maintains an HDMI network for CEC control including the source devices connected to the two or more HDMI terminals, a video transmission system can actively supply a video signal to two or more source devices at the same time, and display videos of them by using the display device at the same time.

Second Embodiment

FIG. 4is a block diagram illustrating a connection example of a control communication line of the video transmission system according to the present embodiment. Source devices11and12are connected to the display device40through an audio amplifier20as a repeater, and a source device13is connected to the display device40through a video interface such as an HDMI cable.

In the present embodiment, control communication lines (CEC lines)101and102, and103and104included in the HDMI cables are connected through a CEC controller212and the CEC controller412, respectively. Examples of the source devices11,12, and13include a DVD player, a DVD recorder, a Blu-ray Disc player, a Blu-ray Disc recorder, an HDD recorder, a broadcast reception set top-box, and a media tuner.

FIG. 5is a block diagram illustrating a configuration example of the audio amplifier20illustrated inFIG. 4. An HDMI receiver211decodes a video signal produced from source devices (not illustrated) connected to two or more video input ports such as HDMI terminals201,202, and203, and supplies the decoded video signal to an audio visual processing unit213. The HDMI receiver211has a function of supplying two or more video signals to the audio visual processing unit213at the same time.

The audio visual processing unit213selects an input signal of the HDMI receiver211or combines selected plural input signals (e.g., combines video signals supplied to HDMI terminals1and2) to supply to an HDMI transmitter221. At the same time, the audio visual processing unit213supplies an audio signal added to the supplied video signal to a speaker216, and the speaker216reproduces a voice. The HDMI transmitter221outputs a signal output from the audio visual processing unit213to the display unit (not illustrated) through an HDMI output port231.

FIG. 6illustrates one example of transmission and reception of the CEC message in the video transmission system ofFIG. 4. Video switching of two or more source devices and multiple-screen display operations will be described below by usingFIG. 6.

According to the HDMI specifications, the display device40acquires a physical address [0000], the audio amplifier20connected to a first HDMI terminal of the display device40acquires a physical address [1000], and the source device13connected to a second HDMI to final of the display device40acquires a physical address [2000]. The source devices11and12connected to HDMI input ports of the audio amplifier20acquire physical addresses [1100] and [1200], respectively.

In an initial state ofFIG. 6, a video of the source device12s assumed to be supplied to the display device40through the audio amplifier20and displayed on a screen451of the display device40.

Next, the source device13supplies to all of the devices (Broadcast) an active source [2000]501in which its own physical address is put to a CEC message for starting a video output. Since the CEC line in the HDMI terminal of the display device40is independent, only the display device40receives the CEC message. When the display device40causes the HDMI terminal having connected thereto the source device13to receive videos, the source device13starts (551) the video output. The display device40receives the video output from the source device13, and performs a two-screen display mode as in a screen452as an image in which its image from the source device13is combined with that previously received from the source device12.

When the display device40switches the video from the source device13over to a full-screen display mode as in a screen453from the two-screen display mode452, the video output from the source device12is not required. To cope with the above problem, the CEC controller412within the display device40transfers the CEC message <active source> [2000]501sent by the source device13to the CEC controller212within the audio amplifier20as a CEC message <active source> [2000]502.

The CEC controller212further transfers the CEC message <active source> [2000]502to the source device12as a CEC message <active source> [2000]503, and the source device12stops (552) the image output. The CEC controller212may transfer the CEC message <active source> [2000]502also to the source device11as a CEC message <active source> [2000]504. However, since the source device11fails to output the video to the audio amplifier20, a transfer for stopping the video output as an aim is not required.

Subsequently, the source device11sends a CEC message <active source> [1100]505for starting the video output. When the audio amplifier20causes the HDMI terminal having connected thereto the source device11to receive a video signal, the source device11starts (553) the video signal output. Since the CEC line in the HDMI terminal of the audio amplifier20is independent, the CEC controller212transfers a CEC message <active source> [1100]507to the display device40.

The display device40causes the HDMI terminal having connected thereto the audio amplifier20to receive videos, and receives a video output from the source device11through the audio amplifier20. Then, the display device40performs a two-screen display mode as in a screen454as an image in which the image output from the source device11is combined with that output from the source device13. The CEC controller212may transfer he CEC message <active source> [1100]505also to the source device12as a CEC message <active source> [1100]506. However, since the source device12fails to output the video to the audio amplifier20, a transfer for stopping the video output as an aim is not required.

When the display device40switches the video from the source device11over to a full-screen display mode as in a screen455from a two-screen display mode454, the video output from the source device13is not required. To cope with the above problem, the CEC controller412within the display device40transfers a CEC message <active source> [2000]507transferred by the audio amplifier20to the source device13as a CEC message <active source> [2000]508, and as a result the source device13stops (554) the video output.

The source device12sends a CEC message <active source> [1200]509for starting the video output to all the devices. Then, the audio amplifier20causes the HDMI terminal having connected thereto the source device12to receive videos, and the source device12starts (555) the video signal output. The audio amplifier20receives a video signal also from the source device12in addition to the source device11, and starts (556) supplying a two-screen combination video signal. Since no change occurs in the display device40, it displays the two-screen combination video transmitted from the audio amplifier20on a screen456.

The audio amplifier20moves (557) from the two-screen display mode to the full-screen display mode of videos from the source device12. Then, the display device40which displays a video output from the audio amplifier20displays a video from the source device12on the full screen as illustrated in a screen457. In the above-described state, since the video output from the source device11is not required, the CEC controller212within the audio amplifier20transfers a CEC message <active source> [1200]509transferred by the source device12to the source device11as a CEC message <active source> [1100]510, and as a result the source device11stops (558) the video signal output.

The CEC controller212of the audio amplifier20transfers the CEC message <active source> [1200] to the display device40as a CEC message <active source> [1200]511, and notifies the display device40that the video from the source device12is displayed on the full screen. The CEC controller of the display device40may transfer a CEC message <active source> [1200]512to the source device13. However, since the source device13fails to output the video to the display device40, a transfer for stopping the video output as an aim is not required.

For simplifying explanation, the description is made by using only the CEC message <active source>. Further, in order that each source device may issue the above message, device operations of a user and other CEC messages such as menu control and remote control code transfer may be used on the way.

Further, in place of the CEC messages502,503,504, and508for the purpose of stopping the video signal output, the CEC message <active source> [0000] which means that the display device40uses a built-in signal source may be used. In a similar fashion, in place of the CEC messages506,507,508,510,511, and512, the CEC message <active source> [1000] which means that the audio amplifier20uses a built-in signal source may be used.

As described above, in a repeater such as an audio amplifier having a function of simultaneously receiving multiple videos and combining and outputting screens, both of two or more HDMI input ports and CEC lines in the HDMI output ports are caused to go independent. When a filtering process or delay process is appropriately performed during the CEC message transfer, a multiple-screen display mode such as a two-screen display mode can be realized at the same time.

A device which is not provided with a screen combination function, for example, the source device avoids the need to cause the CEC line to go independent, or respond to a new CEC message. Therefore, a special consideration is not required to realize the above function, and a user-friendly video transmission system having high backward compatibility can be built.

In addition, the backward compatibility on the audio amplifier will be further described.FIG. 7illustrates operations of the case where a conventional audio amplifier21to which CEC lines are commonly-connected is substituted for the audio amplifier20ofFIG. 6. The same reference numerals as those ofFIG. 6are given to the same components as inFIG. 6.

Processes of the display screens451to455of the display device40are the same as those ofFIG. 6.FIG. 7differs fromFIG. 6in the following points. That is, the CEC controller412transfers the CEC message <active source> [2000]502to the source devices11and12through the audio amplifier21; however, the same display as in an example ofFIG. 6can be performed. Further, the source device11also transfers the CEC message <active source> [1100]505to the source device12and the display device40through the audio amplifier21; however, the same display as in an example ofFIG. 6can be performed.

As compared with an example ofFIG. 6, when the source device12issues the CEC message <active source> [1200]509, the display device40changes the display. InFIG. 6, the display device40realizes the two-screen display mode456only when the audio amplifier20delays the message transfer. As compared the above, inFIG. 7, since the audio amplifier21which receives the above message performs an input switching operation, the display device40displays a switching display screen457.

However, the audio amplifier21is a conventional device which is not provided with a screen combination function, and this operation can't be helped. With regard to every function except the above function, approximately the same functions are realized inFIGS. 6 and 7, and it is understood that high backward compatibility is adopted.

As described above, an example where the audio visual processing unit213combines two or more video signals is described. Further, the audio visual processing unit213can be similarly applied even when two or more videos are output so that video signals are not combined and supplied to the HDMI transmitter221as two or more video signals and the HDMI output port transmits a left eye video and right eye video of 3-D video format at the same time.

Further, the video transmission system may be configured so as to change a combination of videos and voices. For example, a video signal from the source device11may be combined with an audio signal from the source device12to produce the combined signal, which video signal and audio signal of the source devices11and12are used may be determined by default of each repeater or display device. Alternatively, <Active Audio Source> and <Active Video Source> may be defined as a new CEC message.

Third Embodiment

FIG. 8illustrates one example of transmission and reception of the CEC message in the video transmission system ofFIG. 4. InFIG. 6, each source device sends the CEC message <Active Source> for starting the video output, and starts the multiple-screen display mode. On the other hand, inFIG. 8, the display device40sends a request for starting the video output to each source device. The same reference numerals as those ofFIG. 6are given to the same components as inFIG. 6. Video switching of two or more source devices and multiple-screen display operations will be described below by usingFIG. 8.

In the same manner as inFIG. 6, a video of the source device12is first displayed on the screen451of the display device40.

Next, when the display device40sends to all the devices (Broadcast) the CEC message <Set Stream Path> [2000]521that the video is requested to be output to the source device13, the source device13starts (561) the video output.

Since the CEC lines in the HDMI terminals of the display device40go independent, the above message521is not sent to the side of the audio amplifier20. The video signal from the source device12is continuously supplied to the display device40. The display device40performs the two-screen display mode as in the combined screen452of videos from the source devices12and13.

When the display device40switches a video from the source device13over to the full-screen display mode as in the screen453from the two-screen display mode452, a video output from the source device12is not required. To cope with the above problem, the CEC controller412within the display device40sends the CEC message <Set Stream Path> [2000]522to the CEC controller212within the audio amplifier20.

The CEC controller212transfers the CEC message <Set Stream Path> [2000]522to the source device12as the CEC message <Set Stream Path> [2000]523, and the source device12stops (562) the video output. Further, the CEC controller212may transfer the CEC message <Set Stream Path> [2000]522also to the source device11as the CEC message <Set Stream Path> [2000]524. However, since the source device11fails to output the video to the audio amplifier20, a transfer for stopping the video output as an aim is not required.

Subsequently, the display device40sends to all the devices (excluding the source device13) the CEC message <Set Stream Path> [1100]525that the video output of the source device11is requested to be started. Then, the CEC controller212of the audio amplifier20transfers the CEC message <Set Stream Path> [ 1100]525to the source device11as the CEC message <Set Stream Path> [1100]526. Similarly, the HDMI to final to which the source device11is connected is changed to be a video reception mode, and the source device11starts (563) the video signal output. The display device40receives videos output from the source device11through the audio amplifier20, and performs the two-screen display mode as in the screen454as an image in which one image output from the source device11is combined with another image output from the source device13. Further, the CEC controller212may transfer the CEC message <Set Stream Path> [1100]525also to the source device12as the CEC message <Set Stream Path> [1100]527. However, since the source device12fails to output the video to the audio amplifier20, a transfer for stopping the video output as an aim is not required.

When the display device40switches a video output from the source device11over to the full-screen display as in the screen455mode from the two-screen display mode454, a video output from the source device13is not required. To cope with the above problem, the CEC controller412of the display device40sends to the source device13the CEC message <Set Stream Path> [1100] or <Active Source> [1100]528that since the source device11becomes a new video output source, the video output from the source device13may be stopped, and the source device13stops (564) the video output.

The display device40sends to the audio amplifier20the CEC message <Set Stream Path> [1200] [multi]529that two-screen display modes of the source devices11and12are requested to be started. The audio amplifier20changes the HDMI terminal having connected thereto the source device12to have a video reception mode, and sends to the source device12the display start requesting CEC message <Set Stream Path> [1200]530from which a [Multi] parameter is excluded. The source device12starts (565) the video signal output.

The audio amplifier20receives a video signal also from the source device12in addition to the source device11, and starts (566) to output a two-screen combination video signal. The display device40receives the CEC response message <Routing Information> [1200] [Multi]531from the audio amplifier20, and knows that the two-screen display signal is produced from the audio amplifier20. The display device40displays this two-screen video on the screen456.

The [Multi] parameter here used is newly added to the HDMI specifications.FIG. 10illustrates a definition example of the CEC message. In the present embodiment, the [Multi] parameter is used as a parameter indicating the two-screen display mode. The video transmission system has a feature in which when the audio amplifier20excludes the [Multi] parameter during the CEC message transfer, even if the source device as a transfer destination is a device which fails to know a treatment of the above parameter, preferable compatibility connectivity can be maintained.

The [Multi] parameter is not additionally defined, and a <Set 2nd Stream Path> [“Physical Address”] or <2nd Routing Information> [“Physical Address”] may be newly defined and used as a new CEC message code.

When desiring to move from the two-screen display mode to the full-screen display mode of the video from the source device12, the display device40sends the CEC message <Set Stream Path> [1200]532to the audio amplifier20. As a result, the audio amplifier20starts to singly output (567) a video signal from the source device12, and the full-screen display mode457of a video from the source device12is obtained. In this state, since the video output from the source device11is not required, the audio amplifier20sends to the source device11the CEC message <Set Stream Path> [1200] or <Active Source> [1200]534, and stops (558) the video signal output from the source device11.

For simplifying explanation, the description is made by using only the CEC message <Set Stream Path> [1200]. Further, in order that the display device40may issue the above message, device operations of a user and other CEC messages (e.g., menu control and remote control code transmissions may be used on the way.

Further, in place of the CEC messages522,523,524, and528for the purpose of stopping the video signal output, the CEC message <Active Source> [0000] which means that the display device40uses a built-in signal source may be used. In a similar fashion, in place of the CEC messages526,527,528,533, and534, the CEC message <Active Source> [1000] which means that the audio amplifier20uses a built-in signal source may be used.

As described above, in a repeater such as an audio amplifier having a function of simultaneously receiving multiple images and outputting a combined image, both of two or more HDMI input ports and CEC lines in the HDMI output ports are caused to go independent. When a filtering process or delay process is appropriately performed during the CEC message transfer, the multiple-screen display ode such as the two-screen display mode can be realized at the same time.

Further, a device which is not provided with a screen combination function, for example, the source device avoids the need to cause the CEC line to go independent, or respond to a new CEC message. Therefore, a special consideration is not required to realize the above function, and a user-friendly video transmission system having high backward compatibility can be built.

In addition, the backward compatibility on the audio amplifier will be described.FIG. 9illustrates operations of the case where the conventional audio amplifier21to which the CEC lines are commonly-connected is substituted for the audio amplifier20ofFIG. 8. The same reference numerals as those ofFIG. 8are given to the same components as inFIG. 8.

Processes of the display screens451to455of the display device40are the same as those ofFIG. 8.FIG. 9differs fromFIG. 8in the following points. That is, the CEC message <Set Stream Path> [1200] or <Set Stream Path> [1100]525sent by the display device40is transferred to the source devices11and12through the audio amplifier21; however, an influence is not exerted on a screen display of the display device40.

The display of the display device40changes as compared with an example ofFIG. 8when the display device40issues the CEC message <Set Stream Path> [1200] [Multi]529. The display of the display device40changes depending on how the source devices11and and the audio amplifier21treat a newly-added [Multi] parameter.

When the added [Multi] parameter is ignored, the source device12starts (570) the video output, the audio amplifier21switches (571) the video input over to the source device12, and the source device11stops (569) the video output. This process permits the video from the source device12to be displayed on the full screen as in the screen458.

On the other hand, when the CEC message itself with an additional parameter is ignored, the screen fails to be switched over, and a state of the screen455in which the video output from the source device11is displayed on the full screen is maintained. When the audio amplifier21sends back <Routing Information> [1200] (not illustrated), whether the screen is switched over can be confirmed.

When the display device40issues the CEC message <Set Stream Path> [1200]532, the screen457in which the video of the source device12is displayed on the full screen is obtained in the same manner as inFIG. 8.

The two-screen display mode456is realized inFIG. 8only when a timing difference is provided on the CEC message <Set Stream Path> [1200] sent to the source devices11and12by the audio amplifier20. As compared withFIG. 8, since the audio amplifier21ofFIG. 9is not provided with the above function, an operation for input switching is performed.

However, the audio amplifier21is a conventional device which is not provided with a screen combination function, and this operation can't be helped. With regard to every function except the above function, approximately the same functions are realized inFIGS. 6 and 7, and it is understood that high backward compatibility is adopted.

As described above, the audio visual processing unit213is described by taking the multiple-screen combination as an example. Further, the audio visual processing unit213can be similarly applied even when two or more videos are output so that screens are not combined and supplied to the HDMI transmitter221as two or more video signals and the HDMI output port simultaneously transmits a left eye video and right eye video of 3-D video format at the same time.

Further, a combination of videos and audios may be changed, for example, a video signal from the source device11may be combined with an audio signal from the source device12to produce the combined signal. Whether which video signal and audio signal of the source devices11and12are used may be determined by default of each repeater or display device. Alternatively, a <Set Audio Stream Path> or <Set Video Stream Path> may be defined as a new CEC message.

Fourth Embodiment

FIG. 11illustrates an example in which an additional parameter [Multi] described in the third embodiment is expanded so as to respond to various combination screens, andFIG. 12illustrates an example of the combination screen.

The [Multi] parameter includes a [Position] indicating a display position, a [Layout] indicating a screen combination method, a [3D format] indicating transmission of two independent 2D videos by using a 3D format, an [Audio mix] indicating an audio combining method, and a [Reserved] indicating a reserved area.

The [Layout] indicates eight types of screen combination methods illustrated inFIG. 12. A number in the figure indicates a “Position”. A number without angle brackets falls into a left video, and a number with angle brackets falls into a right video during transmission in the 3D format. Further, “0” indicates a one-screen (=full-screen) display mode, “1” indicates a two-right-and-left-screen display mode, “2” indicates a two-upper-and-lower-screen display mode. “3” to “6” indicate an inserted sub-screen display mode, and a position of the sub-screen indicates upper left, upper right, lower left, and lower right. “7” indicates a four-screen display mode.

The [position] indicates a number illustrated inFIG. 12, for example, a left screen of the left side is defined to be “0” and a right screen of the right side is defined to be “1” inFIG. 12Bin which two screens with the same size are aligned from side to side. When setting the [3D format] to “1”, the left side of a left eye video indicates a [Position] of “0”, the right side of a left eye video indicates a [Position] of “1”, the left side of a right eye video indicates a [Position] of “2”, and the right side of a right eye video indicates a [Position] of “4”.

In the [Audio mix], “0” means that only voices of the selected source device are transmitted, “1” means that voices of the selected source device are combined and transmitted, “2” means that voices of the selected source device fail to be transmitted, and “3” means that all the audio signals of the source device in which video signals are output are transmitted.

Further, a case of the [Audio mix]=“3” will be specifically described. In the HDMI specifications, since a linear pulse code modulation (LPCM) audio of eight channels can be transmitted, an audio channel is defined according to a [Position] parameter. For example, in the case of four screens or less, the audio channel is set to a stereo audio. The stereo audio added to videos of the [Position]=“0” may be sequentially allocated to the audio channels of 0 and 1, and the stereo audio added to videos of the [Position]=“1” may be sequentially allocated to the audio channels of 2 and 3.

In the case of more than four screens, the audio channel is set to a monaural audio. The monaural audio added to videos of the [Position]=“0” may be sequentially allocated to the audio channel of 0, and the monaural audio added to videos of the [Position]=“1” may be sequentially allocated to the audio channels of 1.

Except for the description method ofFIG. 11, a parameter can be added and, for example, a size or position of an image during the screen combination can be specified. When providing for a case where an unsupported screen combination function is requested, an error code may be defined separately. Alternatively, when the above function is unsupported, a two-screen combination method considered to be nearer to it may be appropriately used, and further setting results may be sent back. Further, whether the above function can support what screen combination is previously inquired, and a message for responding the above inquiry may be additionally defined.

These features of the fourth embodiment permit useful screen combinations and voice transmissions to be realized from two or more video signals and audio signals.

Fifth Embodiment

FIG. 13is a block diagram illustrating a connection example of a control communication line for e video transmission system according to the present embodiment.FIG. 13differs fromFIG. 4in that a CEC line101for the input and a CEC line103for the output of an audio amplifier22are connected to each other.

FIG. 14is a block diagram illustrating a configuration example of the audio amplifier22ofFIG. 13.FIG. 14differs fromFIG. 5in the following points. That is, one CEC line connected to the HDMI output port231is connected to another CEC line of the HDMI (input) terminal201, and the number of the CEC lines for connection of the CEC controller222is smaller by one than that ofFIG. 5. When the number of CEC independent control lines is reduced, there is exerted an effect of not only reducing the number of terminals for LSI, but also reducing the number of transfer control lines to decrease a size of the CEC controller.

FIG. 15illustrates one example of transmission and reception of the CEC message in the video transmission system ofFIG. 13. The same reference numerals as those ofFIG. 6are given to the same components as inFIG. 6.

Processes of the display screens451to457of the display device40are the same as those ofFIG. 6.FIG. 15differs fromFIG. 6in the following points. That is, the CEC message <Active Source> [2000]502transferred by the CEC controller412is transferred to the source device11through the audio amplifier22; however, an influence is not exerted on the screen display of the display device40.

Further,FIG. 15differs fromFIG. 6also in that the source device11sends the CEC message <Active Source> [1100]505to the display device40through the audio amplifier22; however, an influence is not exerted on the screen display of the display device40.

InFIG. 6, before saving the video from the source device12and moving to the screen457for displaying the video, the audio amplifier20sends the CEC messages <Active Source> [1200]510and511to the source device11and the display device40, respectively. As compared with the above, inFIG. 15, the CEC lines connected to the source device11and the display device40are commonly-connected to the audio amplifier22. Therefore, the CEC message <Active Source> [1200]511is sent to the source device11and the display device40at the same time. However, the above also fails to exert an influence on a fundamental operation within the video transmission system, and also on the screen display of the display device40.

As can be seen from the above sequence, the video transmission system can realize a simultaneous display function of multiple screens more simply.

Sixth Embodiment

FIG. 16illustrates one example of transmission and reception of the CEC message in the video transmission system ofFIG. 13. The same reference numerals as those ofFIG. 8are given to the same components as inFIG. 8.

Processes of the display screens451to457of the display device40are the same as those ofFIG. 6.FIG. 16differs fromFIG. 6in the following points. That is, the CEC controller412sends the CEC messages <Set Stream Path> [2000]522, <Set Stream Path> [1100]525, and <Set Stream Path> [1200]532to the source device11through the audio amplifier22; however, the above fails to exert an influence on the screen display of the display device40and the fundamental operation of the source devices11and12.

Next, description will be made on operations of the source device11at a time when the CEC message <Set Stream Path> [1200] [Multi]529including a newly-added parameter [Multi] is supplied to the source device11. When the source device11correctly interprets this message including the new parameter [Multi], or ignores the message itself, it operates without problems in the same manner as inFIG. 6. However, there is a problem that when only the new parameter [Multi] is ignored, a video signal is interpreted to be switched over and the video signal output (569) is not maintained, and stopped.

For providing for a stop of the video signal output, the audio amplifier22includes a detector which detects a stop of the video signal output. When the video signal output is determined to be stopped, the video output from the source device12is changed from the two-screen display mode to the full-screen display mode so that a black screen with no video can be prevented from being displayed.

As cited in the description of the third embodiment, the [Multi] parameter is not additionally defined, and CEC messages <Set 2nd Stream Path> [“Physical Address”] and <2nd Routing Information> [“Physical Address”] may be newly defined as a new CEC message code. The video transmission system has a feature in which when defining the new message, since the source device failing to respond to the new [Multi] parameter ignores the new message more securely, the above-described problem is solved.

As described above, a repeater is described by taking the audio amplifier as an example. When the present embodiment is applied to a video device having a video output port and two or more video input ports such as a video combination device, a recorder, and a set top-box, the same effect can be exerted.

Seventh Embodiment

FIG. 17is a block diagram illustrating a connection example of a control communication line for the video transmission system according to the present embodiment.FIG. 17differs fromFIG. 13in that another display device43is connected between the display device40and the audio amplifier22. The display device43is further connected to another source device14. A bracket [xxxx] represents a physical address defined by the HDMI specifications. There are formed a CEC network701in hick the display device40is set to a root address [0000] of the physical address and a CEC network702in which the display device43is set to a root address [0000] of the physical address.

FIG. 20is a table illustrating a contrast example of the physical address and the logical address in the CEC network ofFIG. 17. A substantial physical address and logical address are acquired based on the definition of the HDMI in each of the CEC networks701and702. On the assumption of an integrated network of the CEC networks701and702, a visual physical address and logical address are assumed by devices within each CEC network for cooperation control.

The visual physical address of the video device of the CEC network702viewed from the CEC network701is obtained by copying the physical address belonging to the CEC network702into a portion “000” (three digits from right) of the physical address of the output port of the display device43as a device relating to the physical address [1000] of the output port of the display device43. The visual physical address of the video device of the CEC network701viewed from the CEC network702has the same [0000] as that of the display device43. The video device is treated as an internal device of the display device43.

As the visual logical address of the video device of the CEC network702viewed from the CEC network701, the logical address belonging to the CEC network702is used. However, a “4” Playback1already acquired by the source device13is not redundantly used. Therefore, a “8” Playback2and a “11” Playback3are used in the source devices11and12, respectively. Since no logical address can be acquired in the source device14, a “15” Unregistered is used. The visual logical address of the video device of the CEC network701viewed from the CEC network702is assumed to be the same “0” TV as that of the display device43.

The display device43stores the above-described reference table. Further, In a message exchange between the CEC networks701and702, conversion between the physical address and the logical address is performed during the filtering, transfer, and conversion transfer operations of the messages.

FIG. 18is a block diagram illustrating a configuration example of the display device43illustrated inFIG. 17.FIG. 18differs fromFIG. 2in the following points. That is, the audio visual processing unit423separates or selectively outputs one screen portion from a combination video stream or two or more video streams, and transmits it from the HDMI transmitter422through the HDMI output port431to another display device (not illustrated). Further, the CEC line in the output port431is connected to the CEC controller412. The antenna and broadcast receiving processing unit ofFIG. 2are omitted. The display device43ofFIG. 18has the same configuration as that in which the display unit415is provided on the audio amplifier20ofFIG. 5.

FIG. 19illustrates one example of transmission and reception of the CEC message in the video transmission system ofFIG. 17. First, the source device11outputs (651) the video signal. The audio amplifier22selects and outputs the video signal (621), and then the display device43displays it on a screen631. The display device40receives a video output from the source device13, and displays it on a screen641.

A user operates so as to display videos from the source device12on the display device40. Then, the display device40sends to the display device43a CEC message <Set Stream Path> [1120]601that the video output from the source device12is requested. The display device43converts the received CEC message601into a new CEC message <Set 2nd Stream Path> [1200] that the second video output described in the third embodiment is requested, and sends the converted CEC message to the audio amplifier22.

The audio amplifier22exchanges the sent CEC message into the normal source device selection request CEC message <Set Stream Path> [1200]603, and sends it to the source device12. Further, the audio amplifier22sends back to the source device43the CEC message <2nd Routing Information> [1200]604that the second video output is notified. Further, the display device43sends back to the display device40the CEC message <Routine Information> [1120]605that the video from the source device12is output.

The source device12which receives the above source device selection request message603starts (652) the video signal output. The audio amplifier22supplies video signals from the source devices11and12to the display device43while combining screens or using a 3D video transmission format. The display device43extracts a video signal to be displayed by itself of the source device11from two or more video signals, and displays it as in the screen632. Further, the display device43extracts the video from the source device12, and supplies the video to the display device40. Then, the display device40displays the video from the source device12as in the screen642.

When controlling the source device12, the display device40sends to the display device43the CEC message <Menu Request>606that a menu display is requested. Then, the display device43transfers to the audio amplifier22the CEC message <Menu Request>607that the logical address in a destination of a header is converted referring to the reference table ofFIG. 20. The audio amplifier22transfers the transferred CEC message to the source device12as the CEC message <menu request>608.

The source device12starts (653) the menu display, and sends back to the audio amplifier22the CEC message <Menu Status>609that a menu display state is notified. The audio amplifier22transfers the above CEC message to the display device43as the CEC message <Menu Status>610. Since this CEC message is sent back from the source device12which supplies the video to the display device40, the display device43determines that it is sent back to the display device40. Further, the display device43transfers the above CEC message to the display device40as the CEC message <Menu Status>611.

Since the menu display is prepared, the display device40sends to the display device43the CEC message <User Control Pressed>612that a predetermined remote control code is notified through a remote control operation of the user. After performing a process such as a destination conversion, the display device43transfers the above CEC message to the audio amplifier22as the CEC message <User Control Pressed>613. Further, the audio amplifier22transfers the CEC message <User Control Pressed>614to the source device12. This process permits the user to realize the menu selection operation.

The display device40sends to the display device43the CEC message <Set Stream Path> [1110]615that the video from the source device11is requested. The display device43itself displays the video from the source device11, and therefore sends back to the display device40the CEC message <Routing Information> [1120]616which represents a current video transmission route maintenance or the CEC message <Feature Abort> which represents that the video from the source device11cannot be transmitted.

At this time, when the display device40can receive the video format received by the display device43, the display device43may send back to the display device40the CEC message <Routing Information> [1110] (not illustrated) which represents that the video from the source device11is switched over according to the instruction, and may transmit the video signal from the source device11to the display device40.

When switching over to the broadcast as the reception display (643) by using a built-in tuner, the display device40notifies the display device43that the video output from the source device12is not required, for example, by using the CEC message <active source> [0000]643. The display device43stops an operation of extracting the video of the source device12from the videos received from the audio amplifier22and transmitting the extracted video to the display device40. At the same time, the display device43sends to the audio amplifier22the new CEC message <Clear 2nd Stream Path> [1200]618which notifies it that the video from the source device12is not required to be combined and transmitted.

The audio amplifier22aborts the combination video transmission. Further, the audio amplifier sends to the source device12the CEC message <Set Stream Path> [1100] or <Active Source> [1100] which notifies it that the video from the source device12is not required. The source device12then stops (654) the video signal output.

The video signal described in the present embodiment indicates a video and audio signal to which an audio signal belongs. In the above-described example, the display device43extracts the video and audio signal and transmits it to the display device40. Further, the display device43may extract only the video signal or only the audio signal, and transmit it to the display device40.

Through the above-described processes, the display devices40and43can arbitrarily display videos from the same source device. When failing to performing their processes, each source device or a repeater such as an audio amplifier is required to have two or more video outputs for the display devices40and43and independent CEC control. In addition, a special source device is required to be prepared. Further, the connection cable between devices approximately doubles. According to the present embodiment, an effect capable of solving the above botheration is exerted.

In the above description, a display device and an audio amplifier as a repeater are described by using an example; however, it is not limited thereto. When the repeater has an output port and two or more input ports, the present embodiment is applicable to the video transmission system.

Further, the description is made on the premise of the wired connection, and further even if wireless connection is performed, the present invention exerts the above effect. The proposed video transmission system has a feature in which in the wireless connection, the number of channels to be used is saved in place of the number of cables.