JP5479140B2 - Video / audio signal receiving apparatus and control method - Google Patents

Description

  The present invention relates to a video / audio signal transmitting device that determines a video / audio signal to be output according to a reception specification read from the video / audio signal receiving device, a video / audio signal receiving device having a video / audio signal reception processing unit, and a video synthesizing unit. The present invention relates to a video / audio signal receiving apparatus and a control method in a video / audio signal transmission system including a transmission path of a digital interface connecting the video / audio signal transmitting apparatus and the video / audio signal receiving apparatus.

  As one of the video and audio signal transmission standards, HDMI (High Definition Multimedia Interface), which is a standard for transmitting digitized video and audio data, is widely used (see, for example, Non-Patent Document 1).

  Among HDMI cables compliant with the HDMI standard, there are TMDS (Transition Minimized Differential Signaling) lines that transmit digital audio and video signals and DDC (Display Data Channel) lines that transmit information on the video and audio signal receiving device side. To do.

  The information on the side of the video / audio signal receiving device transmitted via the DDC line includes information indicating the video format and audio format that can be received and processed by the video / audio signal receiving device, and reception specifications including their priority order, The information is called EDID (Extended Display Identification Data). The video / audio signal transmitting device refers to the EDID through the DDC line, determines the priority video format or priority audio format of the video / audio signal receiving device, and determines the video / audio signal to be output to the TMDS line. Do.

  Conventionally, various types of EDID data indicating different display specifications corresponding to a plurality of destinations or receiving operations are stored in advance in a nonvolatile memory, and when a television receiver is installed, it corresponds to the location. EDID data indicating display specifications to be taken out from the non-volatile memory and stored in the built-in memory of the HDMI transmission / reception unit, and there was a request for acquisition of EDID data from an electronic device that is a transmission side of signals such as video and audio In this case, the HDMI transmission / reception unit transmits the EDID data stored in the built-in memory to the request-destination device, thereby providing the necessary display specifications, thereby individually providing the EDID data for each of a plurality of types of reception specifications. This eliminates the need to store the battery and facilitates manufacturing and shipping operations. A child device is known (see, for example, Patent Document 1).

JP 2006-179973 A

High-Definition Multimedia Interface Specification Version 1.3a

However, the video synthesizer synthesizes the terrestrial digital broadcast video and the video of the HDMI input video / audio signal (that is, the digital video / audio signal compliant with the HDMI standard received via the TMDS line) as a video for two-screen display. However, when displaying on the display unit, if the two video formats match in NTSC or PAL, it can be combined as a two-screen display video. It is possible to display.

  However, in a video / audio signal receiving apparatus capable of displaying two screens of a digital terrestrial broadcast video signal and an HDMI input video signal, different video formats (for example, NTSC (National Television System Committee) and PAL (Phase Alternating Line)). ) Input video simultaneously, the two frame rates (that is, the number of video frames displayed on the screen per second) are different from each other, so that both videos cannot be displayed correctly on one screen.

  That is, if the two video formats to be displayed on the display do not match between NTSC and PAL, it is impossible to synthesize both videos as a two-screen display video. It is impossible to display and appreciate. For this reason, the conventional technique has a problem that only the previously displayed image is displayed, and the image selected later cannot be displayed.

  The present invention has been made in order to solve the above-described problems. By making the video format output from the video / audio signal transmission device into a video format consistent with terrestrial digital broadcasting, two-screen display is impossible. Aims to remedy the situation.

A video / audio signal receiving device according to the present invention is a video / audio signal receiving device connectable to a video / audio signal transmitting device via a transmission line, and the video signal currently processed by the video / audio signal receiving device. A reception specification storage unit that stores information representing the format in an updatable manner, and a system control unit that causes the video / audio signal transmission device to read information representing the video format stored in the reception specification storage unit via the transmission path; A video synthesizing unit that synthesizes and outputs the video signal currently processed by the video / audio signal receiving device and the video signal transmitted from the video / audio signal transmitting device; The video signal transmitted to the video / audio signal receiving device and synthesized by the video synthesis unit with the video signal currently processed by the video / audio signal receiving device is the reception specification rating. Stored in said part image audio signal receiving apparatus is obtained as is the video signal corresponding to the information indicating the video format that is currently processed.

The control method according to the present invention is a control method used for a video / audio signal receiving device connectable to a video / audio signal transmitting device via a transmission line, and is currently processed by the video / audio signal receiving device. Detecting a video format of the received video signal, storing information representing the detected video format, reading the stored information into the video / audio signal transmitter, and reading the video / audio signal transmitter When the video signal corresponding to the information representing the video format currently processed by the video / audio signal receiving device is received from the video / audio signal transmitting device, the video signal received from the video / audio signal transmitting device and the current And a step of synthesizing and outputting the video signal being processed by the video / audio signal receiving device.

  According to the configuration and method as described above, a plurality of types of reception specifications in which the priorities of the corresponding video formats are exchanged in advance are prepared (for example, EDID having higher priority of NTSC than PAL, for example, PAL having higher priority). EDID is higher than NTSC), stored in the multiple reception specification storage unit, and when the preceding output video format is finalized, the reception specification with the higher priority of the corresponding video format is extracted, and the extracted reception specification is received. By storing in the specification storage unit, when displaying two screens, the video / audio signal transmitting device selects and outputs a video / audio signal of the same video format as the preceding output video format in accordance with the reception specifications, so that it is displayed on two screens. It becomes possible to appreciate the video.

1 is a block diagram of a video / audio signal transmission system according to Embodiment 1 of the present invention. FIG. 7 is an operation flowchart for displaying two screens in the state in which a video signal of terrestrial digital broadcasting in the NTSC video format is output in advance in the video / audio signal transmission system according to the first embodiment of the present invention. In the video / audio signal transmission system according to Embodiment 1 of the present invention, an operation flowchart for displaying two screens in a state in which a video signal of terrestrial digital broadcasting in a PAL video format is being output in advance.

(Embodiment 1)
The video / audio signal transmission system according to Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a video / audio signal transmission system 1 according to Embodiment 1 of the present invention.

  In FIG. 1, the video / audio signal receiving device 10 can be connected to an antenna unit 21, and the antenna 21 is connected to a tuner unit 22 provided inside the video / audio signal receiving device 10.

  In addition to the tuner unit 22, the video / audio signal receiver 10 includes a signal demodulator 23, a first video / audio signal processor 24, an audio playback unit 25, a video / audio signal receiver 31, and a second video / audio signal processor. 32, an EDID storage memory unit 33b, a video composition unit 40, a display unit 50, a system control unit 60b, and a plurality of EDID storage memory units 90 are provided.

  The video / audio signal receiving device 10 is electrically connected to the video / audio signal transmitting device 80 via the TMDS line 71 and the DDC line 72.

  The antenna unit 21 is a part that is connected to the video / audio signal receiving device 10 and receives a digital terrestrial broadcast signal. The received digital terrestrial broadcast signal is transmitted to the tuner unit 22.

  The video / audio signal receiving device 10 receives and processes terrestrial digital broadcast video / audio signals received from the antenna unit 21 (a tuner unit 22, a signal demodulation unit 23, a first video / audio signal processing unit 24). And an HDMI input signal processing block 30 (video / audio signal receiving unit 31, second video signal processing unit 32) for receiving and processing HDMI-input video / audio signals, and each processed video signal And a display unit 50 for displaying the video signal synthesized by the video synthesizing unit 40.

  The video signal of the terrestrial digital broadcast and the video signal of the HDMI input are synthesized by the video synthesizing unit 40 and are displayed on the display unit 50 by two screens. In addition, the audio reproduction unit 25 reproduces the received terrestrial digital broadcast or HDMI input audio.

  However, with two-screen display, two different video signals (for example, a digital terrestrial broadcast video signal and an HDMI input video signal) are combined and divided on the same display (for example, divided horizontally or divided vertically) To display at the same time. One-screen display (that is, displaying one video signal on one display) and two-screen display can be arbitrarily switched by a user operation, and the system control unit 60b controls the video composition unit. Manages switching between 1-screen display and 2-screen display.

  The tuner unit 22 is a part that tunes the terrestrial digital broadcast signal received by the antenna unit 21 and selects only a desired signal. The terrestrial digital broadcast signal tuned by the tuner unit 22 is a signal demodulator in the subsequent stage. 23.

  The signal demodulator 23 is a part for demodulating the signal tuned by the tuner 22, and the demodulated digital terrestrial broadcast signal is transmitted to the first video / audio signal processor 24 at the subsequent stage.

  The first video / audio signal processing unit 24 is a part for processing the video / audio signal of the terrestrial digital broadcast demodulated by the signal demodulating unit 23, and the video signal, the audio signal, and the like are processed by the first video / audio signal processing unit. To separate.

  The audio signal separated by the first video / audio signal processing unit 24 is transmitted to the audio reproduction unit 25 to be subjected to audio reproduction processing. The video signal separated by the first video / audio signal processing unit 24 is transmitted to the video synthesis unit 40 at the subsequent stage. The first video / audio signal processing unit 24 detects the format of each video / audio signal.

  The audio reproduction unit 25 performs a process of reproducing the audio signal separated by the first video / audio signal processing unit and the second video / audio signal processing unit. This processing operation is controlled by the system control unit 60.

  The video / audio signal receiving unit 31 is connected to the video / audio signal transmitting device 80 by the TMDS line 71 and is a part that receives the video / audio signal transmitted from the video / audio signal transmitting device 80 via the TMDS line 71.

  The received HDMI input video / audio signal is transmitted to the second video / audio signal processing unit 32.

  The second video / audio signal processing unit 32 is a part that processes the video / audio signal of HDMI input received by the video / audio signal receiving unit 31, and separates it into a video signal and an audio signal.

  The audio signal separated by the second video / audio signal processing unit 32 is transmitted to the audio reproduction unit 25 to be subjected to audio reproduction processing. Similarly, the video signal separated by the second video / audio signal processing unit 32 is transmitted to the video synthesis unit 40 in the subsequent stage. The second video / audio signal processing unit 32 detects the format of each video / audio signal.

  The video synthesizing unit 40 is a part that synthesizes the two video signals processed by the first video / audio signal processing unit 24 and the second video / audio signal processing unit 32.

  The video composition unit 40 acquires the video format information of the two video signals from the system control unit 60b, and performs video composition processing. However, in the case of one-screen display, synthesis is not performed and a single-screen video signal is generated.

  The display unit 50 is a part for displaying the video signal received from the video synthesis unit 40 on the display. However, the display unit 50 may not be provided integrally with the audio / video signal receiving apparatus 10 and may be configured to be connectable to an externally arranged device.

The system control unit 60b is a part for controlling the entire system of the video / audio signal receiving apparatus 10, and includes, for example, an integrated circuit including a CPU, a ROM, and a RAM. CPU is RO
By executing the computer program stored in M while using the RAM as a work area, at least each of the above-described parts is controlled.

  The TMDS line 71 is a transmission path existing in the HDMI cable, and transmits a video / audio signal digitized based on the HDMI standard. The TMDS line 71 electrically connects the video / audio signal transmitter 80 and the video / audio signal receiver 31 of the video / audio signal receiver 10.

  The DDC line 72 is a transmission path existing in the HDMI cable, and transmits EDID indicating the reception specification of the video / audio signal receiving device 10 to the video / audio signal transmitting device 80 based on the HDMI standard.

  The DDC line 72 connects the video / audio signal transmitting device 80 and the system control unit 60b of the video / audio signal receiving device 10, and an EDID storage memory unit 33b in which EDID is stored is also connected to this line. Has been. The video / audio signal transmission device 80 acquires the EDID stored in the EDID storage memory unit 33b via the DDC line, and detects the reception specification of the video / audio signal reception device 10.

  In the present embodiment, the EDID storage memory unit 33 b is connected to the system control unit 60 b by an EDID management line 73 separately from the system control unit 60 b and the DDC line 72.

  The EDID stored in the EDID storage memory unit 33b is managed by the system control unit 60b using the EDID management line 73, and the EDID is rewritten (updated).

  The system control unit 60b is connected by an EDID management line 73 different from the EDID storage memory unit 33b and the DDC line, and manages the EDID stored in the EDID storage memory unit 33b.

  When the video format of the terrestrial digital broadcast is detected from the first video / audio signal processing unit 24, an EDID having a higher priority of the detected video format is selected from the plurality of EDID management memory units 90 and stored in the EDID. It stores in the memory unit 33b.

  The EDID management line 73 connects the system control unit 60b and the EDID storage memory unit 33b, and changes and manages the EDID stored in the EDID storage memory unit 33b through this line.

  The plurality of EDID storage memory units 90 are a plurality of types of EDIDs in which the priority order of the corresponding video format included in the EDID is changed according to the video format (for example, EDID having a higher NTSC priority than PAL or PAL priority). This is a memory unit for storing in advance EDID whose rank is higher than that of NTSC. It is managed by the system control unit 60b.

  The video / audio signal transmission device 80 is a device that transmits a digitized video / audio signal, and receives the EDID from the EDID storage memory unit 33 a in the video / audio signal reception device 10 connected via the reception specification transmission line 72. The video / audio signal suitable for the reception specification of the video / audio signal receiving device 10 is read and transmitted from the video / audio signal transmission line 71.

The processing operation of the video / audio signal transmission system configured as described above will be described below.

  2 and 3 show the video / audio signal transmission system according to the first embodiment of the present invention in a state where the video signal of the terrestrial digital broadcast has already been output to the display unit 50 in advance (output in advance). It is an operation | movement flowchart which shows the operation | movement flow in the case of switching to a screen display and displaying two screens of the image | video received by the image | video of a terrestrial digital broadcasting, and a video audio signal receiver. FIG. 2 is a flowchart showing an operation flow when the video format of terrestrial digital broadcasting is particularly NTSC, and FIG. 3 is a flowchart showing an operation flow when the video format of terrestrial digital broadcasting is particularly PAL.

  First, the operation flow when the video format of terrestrial digital broadcasting is particularly NTSC will be described below with reference to the flowchart of FIG.

  At the start of system operation, it starts from a mode in which an image of digital terrestrial broadcasting is displayed on one screen on the display unit as an initial state. Note that the digital terrestrial broadcast video is NTSC (step S200a).

  Upon receiving the terrestrial digital broadcast signal from the antenna unit 21, the video / audio signal receiving apparatus 10 tunes the signal by the tuner unit 22, and extracts only the terrestrial digital broadcast signal of the desired channel.

  The digital terrestrial broadcast signal extracted by the tuner unit 22 is demodulated from the digital signal by the demodulation unit 23, and the demodulated signal is separated into a video signal and an audio signal by the video / audio signal processing unit 24, and each process is performed (step S201a). ).

  The system control unit 60b manages the processing content of step S201a, and acquires information of the video / audio signal received by terrestrial digital broadcasting (step S202a).

  Here, the system control unit 60b detects the video format of the video signal being processed (currently) at this time and writes it to the EDID storage memory unit 33b. That is, a corresponding video format (that is, a video format that can be received by the video / audio signal receiving device and can be displayed on the display) from a plurality of EDIDs stored in the memory unit 90 for storing a plurality of EDIDs. Among them, the NTSC reads the EDID having a higher priority than the PAL, and writes the corresponding EDID into the EDID storage memory unit 33b (step S203a).

  The video signal processed by the video / audio signal processing unit 24 is transmitted to the video synthesis unit 40 in the subsequent stage. The video composition unit 40 generates a digital terrestrial broadcast video as a single-screen NTSC video under the control of the system control unit 60b and displays it on the display unit (step S204a).

  After the process of step S204a, the audio / video signal transmitting apparatus 80 capable of outputting both NTSC and PAL video formats is connected by the user, and the display on the display is switched from the one-screen display to the two-screen display (step S205a). ).

  At this time, the video / audio signal transmitter 80 reads the EDID from the EDID storage memory unit 33b via the reception specification transmission line 72 (step S206a).

When the video / audio signal transmission device 80 reads EDID in step S206a, the video / audio signal transmission device 80 confirms the reception specification of the video / audio signal reception device 10 from the read EDID.

  The video / audio signal transmitting device 80 preferentially selects the video / audio signal with the highest priority recommended by the video / audio signal receiving device 10 from the video / audio formats that can be output by the video / audio signal, and outputs the video / audio signal output by itself. (Step S207a).

  In this case, since the priority order of the video format of NTSC is high in EDID, the video / audio signal transmitting device 80 determines the video format to be output as HDMI to NTSC, and the video / audio signal receiving device 10 via the video / audio signal transmission line 71. (Step S208a).

  The video / audio signal receiving device 10 receives the HDMI signal output from the video / audio signal transmitting device 80 at the video / audio signal receiving unit 31 via the video / audio signal transmission line 71. The received HDMI signal is separated from the video / audio signal by the video / audio signal processing unit 32 and processed by the video / audio signal processing unit 32. The processed video is transmitted to the video composition unit 40 (step S209a).

  The system control unit 60 manages the processing contents of step S209a and acquires information on the HDMI input video / audio signal. It is detected that the HDMI input video format is NTSC (step S210a).

  The video composition unit 40 is controlled by the system control unit 60b to synthesize the digital terrestrial broadcast and the HDMI signal video. At this time, since the video formats of the terrestrial digital broadcast and the HDMI signal are both NTSC, the settings match and it is possible to synthesize two videos into a two-screen display video (step S211a).

  The synthesized video is transmitted to the display unit 50, and two-screen display is started. At this time, since the two images are synthesized as a two-screen display image, both the terrestrial digital broadcast image and the HDMI signal image are displayed on the display.

  Next, the operation flow when the video format of terrestrial digital broadcasting is particularly PAL will be described with reference to the flowchart of FIG.

  The antenna unit 21 receives the video / audio signal of the terrestrial digital broadcast in the PAL video format (step S200b).

  The received digital terrestrial broadcast signal is separated by the first video / audio signal processing unit 24 (step S201b).

  In step S201b, the system control unit 60b obtains information that the video format of the terrestrial digital broadcast is PAL from the first video / audio signal processing unit 24 (step S202b), and the PAL from the multiple EDID storage memory unit 90. The priority EDID is read and written into the EDID storage memory unit 33b via the EDID management line 73 (step S203b).

In addition, the video composition unit 40 generates a terrestrial digital broadcast video as a one-screen video, and displays the PAL video on the display unit 50 (step S204b).
Here, the video / audio signal transmitting apparatus 80 capable of outputting both NTSC and PAL video formats is connected by the user, and the display is switched from the one-screen display to the two-screen display by the user (step S205b).

  The video / audio signal transmitting device 80 reads out the EDID of the video / audio signal receiving device via the DDC line 72 (step S206b), and determines the video format to be output from the priority video format of the EDID (step S207b).

  In this flowchart, since the priority video format of EDID is PAL, PAL is selected as the video format to be output and is output to the TMDS line 71 (step S208b).

  The second video / audio signal processing unit 32 separates the received video / audio signal (step S209b). At this time, the system control unit 60b performs the video format of the video / audio signal received from the video / audio signal transmitting device 80. Is detected as PAL (step S210b).

  The video composition unit 40 is controlled by the system control unit 60b to synthesize the digital terrestrial broadcast and the HDMI signal video. At this time, since the video formats of the terrestrial digital broadcast and the HDMI signal are both PAL, the settings match and it is possible to synthesize two videos into a two-screen display video (step S211a).

  The synthesized video is transmitted to the display unit 50, and two-screen display is started. At this time, since the two images are synthesized as a two-screen display image, both the terrestrial digital broadcast image and the HDMI signal image are displayed on the display.

  As described above, in the present embodiment, the EDID stored in the EDID storage memory unit, which has been fixed in the past, is replaced with the EDID in which the priority order of the corresponding video format is changed according to the video format of the preceding output (for example, the preceding If the output video format is NTSC, the video / audio signal is transmitted by changing the priority to EDID with higher NTSC priority than PAL, or EDID with higher PAL priority than NTSC if the previous output video format is PAL. The video format output by the device 80 can be output in accordance with the video format output in advance.

  As a result, the video formats displayed on the two screens can be matched without requiring any user operation, and the two video images can be viewed on the two-screen display when either the NTSC or PAL video format is output in advance. It becomes possible.

  In particular, the present embodiment is a video / audio reception device that supports a plurality of types of video formats that are developed globally and is expected to be connected to a video / audio signal transmission device that outputs a plurality of types of video formats. Is useful in a system such as an in-vehicle video / audio transmission system.

  In addition, this invention is not limited to the above-mentioned content, A component can be changed and embodied in the implementation stage in the range which does not deviate from the summary.

  For example, in the present embodiment, the video / audio signal for two-screen display has been described assuming a combination of digital terrestrial broadcasting and a video / audio signal received from an external video / audio signal transmission device, but this is limited to this combination. Is not to be done. For example, the same applies to a built-in video / audio signal reproduction device (for example, a built-in BD (Blu-ray Disc) deck or a built-in DVD (Digital Versatile Disc) deck) instead of terrestrial digital broadcasting.

  Also, for example, it has a connection part with two or more external devices (however, at least one of the connection parts with two or more external devices is a connection part conforming to the HDMI standard) and is received from them. The same is true for a video / audio signal receiving apparatus capable of displaying two video images.

  Further, in the present embodiment, the invention can be formed by appropriately combining a plurality of constituent elements disclosed herein within a range where the effects of the invention can be obtained.

  In this embodiment, when the video format of the preceding output is NTSC and a video / audio signal transmission device that outputs only the video signal of the PAL video format is connected, the priority order of NTSC is PAL with EDID. Even if it is higher than the above, a PAL video signal is transmitted from the video / audio signal transmitting device.

  In this case, the system control unit 60b detects that the high-order video format (ie, NTSC) in the priority order of EDID is different from the video format (ie, PAL) of the HDMI input actually received, and is connected. It is determined that the only video format that can be output by the video / audio signal transmitting apparatus is PAL.

  After the determination, the system control unit 60b matches the video format (that is, PAL) output from the video / audio signal transmitting device with the video format of the video / audio signal that is output in advance, and displays both videos in a two-screen display. In order to enable viewing, by controlling the video format of the video / audio signal output in advance from NTSC to PAL, the two video formats can be made PAL, and the two videos can be displayed on two screens. it can.

  Moreover, although it was set as user operation as conditions which switch to 2 screen display, it is not limited to this condition. For example, the condition for switching to the two-screen display may be a detection that the video / audio signal transmitting apparatus is connected, and the system control unit 60b may automatically switch to the two-screen display after this detection.

  As described above, the video / audio transmission system and the video / audio signal receiving apparatus according to the present invention are assumed to be connected to a video / audio signal transmitting apparatus that outputs a plurality of types of video formats, and two-screen simultaneous display is often used. It is suitable for.

DESCRIPTION OF SYMBOLS 10 Video / audio signal receiving device 20 Digital terrestrial broadcast processing part 21 Antenna part 22 Tuner part 23 Signal demodulation part 24 Video / audio signal processing part 30 HDMI input signal processing part 31 Video / audio signal receiving part 32 Video / audio signal processing part 33b For EDID storage Memory unit 40 Video composition unit 50 Display unit 60b System control unit 71 TMDS line 72 DDC line 73 EDID management line 80 Video / audio signal transmission device 90 Multiple EDID storage memory unit

Claims (6)

A video / audio signal receiving device connectable to a video / audio signal transmitting device via a transmission line,
A reception specification storage unit for renewably storing information indicating a video format of a video signal currently processed by the video / audio signal receiving device, and information indicating the video format stored in the reception specification storage unit in the transmission path and a system controller to load in the video audio signal transmitting apparatus via the video audio signal receiving apparatus by combining the video signal transmitted from the video audio signal transmitting apparatus and a video signal that is currently whereabouts sense A video composition unit for output,
The video signal transmitted from the video / audio signal transmitter to the video / audio signal receiver and synthesized by the video synthesizer with the video signal currently processed by the video / audio signal receiver is stored in the reception specification storage unit. A video / audio signal receiving apparatus, wherein the stored video / audio signal receiving apparatus is a video signal corresponding to information representing a video format currently being processed. A plurality of reception specification storage units that previously store a plurality of information representing video formats that can be processed by the video and audio signal receiving device ;
The system control unit detects a video format of a video signal currently processed by the video / audio signal receiving device, reads information representing the detected video format from the multiple reception specification storage unit, and stores the information in the reception specification storage unit. The video / audio signal receiving apparatus according to claim 1, wherein the stored information is updated.   A video / audio signal receiving unit that processes a transmission signal compliant with the HDMI (registered trademark) standard, wherein the transmission path is a transmission channel compliant with the HDMI (registered trademark) standard, and the transmission path and the video / audio signal receiving unit; The video / audio signal receiving apparatus according to claim 1, wherein   4. The video / audio receiver according to claim 3, wherein the information representing the video format stored in the reception specification storage unit is EDID. A control method used for a video / audio signal receiving device connectable to a video / audio signal transmitting device via a transmission line,
A step of detecting a video format of a video signal currently processed by the video / audio signal receiving device; a step of storing information representing the detected video format; and a step of causing the video / audio signal transmitting device to read the stored information And when the video signal corresponding to the information representing the video format currently processed by the video / audio signal receiving device read by the video / audio signal transmitting device is received from the video / audio signal transmitting device. A control method used for a video / audio signal receiving device, comprising: synthesizing and outputting a video signal received from a signal transmitting device and a video signal currently processed by the video / audio signal receiving device. An integrated circuit used in a video / audio signal receiving device connectable to a video / audio signal transmitting device via a transmission line,
A step of detecting a video format of a video signal currently processed by the video / audio signal receiving device; a step of storing information representing the detected video format; and a step of causing the video / audio signal transmitting device to read the stored information And when the video signal corresponding to the information representing the video format currently processed by the video / audio signal receiving device read by the video / audio signal transmitting device is received from the video / audio signal transmitting device. An integrated circuit used in a video / audio signal receiving apparatus, which executes a step of synthesizing and outputting a video signal received from a signal transmitting apparatus and a video signal currently processed by the video / audio signal receiving apparatus.