Audio playback device, control method, and program

Abstract

An audio reproduction device, which is a source apparatus (10) connected to a sink apparatus (30) in conformity with the HDMI standard, comprises: an ARC reception circuit (16) that receives an ARC signal from the sink apparatus (30); and a video / audio processing circuit (13) that, while the ARC reception circuit (16) is receiving the ARC signal, transmits first video data in which all bits of pixel data have the same value in the Y, Cb, Cr format, to the sink apparatus (30).

Description

[Technical Field]

[0001] The present disclosure relates to an audio playback device, a control method, and a program. [Background technology]

[0002] Conventionally, in the HDMI (registered trademark) (High-Definition Multimedia Interface) standard, an ARC (Audio Return Channel) signal is used so that a source device can reproduce an audio signal output by a sink device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 209097 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the HDMI standard, when transmitting an ARC signal, video data must be transmitted from the source device to the sink device, which can have a negative impact on the quality of the audio being played back by the source device.

[0005] The present disclosure provides an audio playback device, an audio playback method, and a program that suppress the influence of video data transmitted from a source device to a sink device on the quality of audio played back by the source device. [Means for solving the problem]

[0006] The communication control method disclosed herein is an audio playback device that is a source device connected to a sink device in accordance with the HDMI (High-Definition Multimedia Interface) standard, and includes an ARC (Audio Return Channel) receiving unit that receives an ARC signal from the sink device, and a video processing unit that transmits first video data to the sink device, in which all bits of pixel data have the same value in Y / Cb / Cr format, when the ARC receiving unit is receiving the ARC signal. [Effects of the Invention]

[0007] The communication control method according to the present disclosure can suppress the influence of video data transmitted from a source device to a sink device on an ARC signal. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing a system according to an embodiment. [Figure 2] FIG. 2 is a first explanatory diagram showing signals transmitted and received between a source device and a sink device in the system according to the embodiment. [Figure 3] FIG. 10 is a second explanatory diagram showing signals transmitted and received between a source device and a sink device in the system according to the embodiment. [Figure 4] FIG. 4 is a flowchart showing the flow of processing executed by a source device in the system according to the embodiment. [Figure 5] FIG. 10 is a sequence diagram showing the flow of a first process executed by the system according to the embodiment. [Figure 6] FIG. 10 is a sequence diagram showing the flow of a second process executed by the system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Findings that formed the basis of this disclosure) The present inventors have found that the video data transmission technology in the HDMI standard described in the "Background Art" section has the following problems.

[0010] According to the HDMI standard, when transmitting an ARC signal, the source device transmits video data to the sink device.

[0011] The video data is received and processed by the HDMI communication circuit of the sink device. Depending on the configuration of the HDMI communication circuit (e.g., an LSI (Large Scale Integrated circuit)), noise may be generated by the received video data. This noise may be superimposed on the ARC signal, resulting in a degradation of the quality of the reproduced audio. For example, if the bit values ​​included in pixel data in the video data differ from the adjacent bit values, the bit values ​​input to the circuit may fluctuate over time, generating noise within the circuit. This noise may propagate through the HDMI cable and be mixed into the audio playback section of the source device, resulting in noise being included in the audio reproduced by the source device and resulting in a degradation of the quality of the reproduced audio.

[0012] Alternatively, depending on the configuration of the circuit (e.g., LSI) provided in the HDMI communication circuit of the source device, the bit values ​​contained in the pixel data included in the video data to be transmitted may differ from the adjacent bit values, causing noise to be generated within the circuit due to the bit values ​​output by the circuit fluctuating over time. This noise may then be mixed into the audio playback section of the source device, causing noise to be included in the audio being played back, resulting in a deterioration in the quality of the played back audio.

[0013] As described above, the HDMI standard has a problem in that video data transmitted from a source device to a sink device during transmission of an ARC signal can affect the quality of audio played back by the source device.

[0014] The present disclosure provides an audio playback device, an audio playback method, and a program that suppress the influence of video data transmitted from a source device to a sink device on the quality of audio played back by the source device.

[0015] Below, examples of inventions that can be obtained from the disclosure of this specification will be given, and the effects and the like that can be obtained from these inventions will be explained.

[0016] (1) An audio playback device that is a source device connected to a sink device in accordance with the HDMI (High-Definition Multimedia Interface) standard, comprising: an ARC (Audio Return Channel) receiving unit that receives an ARC signal from the sink device; and a video processing unit that transmits to the sink device first video data in which all bits of pixel data have the same value in Y / Cb / Cr format when the ARC receiving unit is receiving the ARC signal.

[0017] According to the above aspect, all bits of pixel data included in the first video data have the same value in Y / Cb / Cr format, thereby suppressing fluctuations in bit values ​​input to the HDMI communication circuit of the sink device. As a result, noise that may be generated by the HDMI communication circuit of the sink device is suppressed, and deterioration in the quality of audio played back by the source device can be suppressed. In this way, the audio playback device can suppress the impact of video data transmitted from the source device to the sink device on the quality of audio played back by the source device after receiving the ARC signal.

[0018] (2) The audio playback device according to (1), wherein the video processing unit transmits the first video data having 0 as the same value.

[0019] According to the above aspect, all bits of pixel data included in the first video data are 0 in Y / Cb / Cr format. In the process performed by the HDMI communication circuit of the sink device, pixel data located outside a region corresponding to pixels constituting the video included in the first video data may be added to the first video data, and the video may be decoded. The pixel data located outside the region may be 0. In this case, by having all bits of pixel data included in the first video data be 0 in Y / Cb / Cr format, fluctuations in bit values ​​input to the HDMI communication circuit of the sink device can be further suppressed. In this way, the audio playback device can further suppress the impact of video data transmitted from the source device to the sink device on the quality of audio played back by the source device after receiving the ARC signal.

[0020] (3) An audio playback device described in (1) or (2), wherein the video processing unit transmits, as the first video data, video data that satisfies at least one of the following: (a) a resolution of 480p or 576p; (b) a color format of Y / Cb / Cr=4:2:2 or 4:2:0; (c) a deep color setting is disabled; and (d) a pixel repetition setting is disabled.

[0021] According to the above aspect, fluctuations in bit values ​​included in the first video data are suppressed. For example, by using a relatively low resolution such as 480p or 576p, the number of bits required for transmission is reduced, thereby suppressing fluctuations in bit values ​​included in the first video data. For example, by using a color format of Y / Cb / Cr=4:2:2 or 4:2:0, the number of bits required for transmission is reduced compared to when Y / Cb / Cr=4:4:4, thereby suppressing fluctuations in bit values ​​included in the first video data. For example, by disabling the deep color setting and pixel repetition setting, the number of bits required for transmission is reduced compared to when they are enabled, thereby suppressing fluctuations in bit values ​​included in the first video data. In this way, the audio playback device can further suppress the impact of video data transmitted from a source device to a sink device on the quality of audio played back by the source device after receiving an ARC signal.

[0022] (4) An audio playback device described in any one of (1) to (3), wherein the video processing unit determines whether the sink device supports a color format of Y / Cb / Cr=4:2:2 or 4:2:0, and transmits the first video data having 0 as the same value only if it determines that the sink device supports the color format.

[0023] According to the above aspect, when the sink device supports a color format of Y / Cb / Cr=4:2:2 or 4:2:0, all bits of pixel data included in the first video data have 0 in the Y / Cb / Cr format. This allows the audio playback device to further reduce the impact of video data transmitted from the source device to the sink device on the quality of audio played back by the source device after receiving an ARC signal.

[0024] (5) An audio playback device described in any of (1) to (4), wherein the video processing unit further transmits second video data different from the first video data to the sink device when it receives a switching signal indicating that the signal source of the sink device is switched to the audio playback device.

[0025] According to the above aspect, it is possible to prevent the sink device from accidentally displaying video based on the first video data output by the source device. As described above, the first video data is a signal including a signal for suppressing fluctuations in bit values ​​input to the HDMI communication circuit of the sink device, and is not intended for a user to view the video based on the first video data. For example, video based on first video data in which all bits of pixel data are 0 in Y / Cb / Cr format is video in which all pixels on the screen are green. Therefore, a user may feel uncomfortable viewing the video based on the first video data. Therefore, when the signal source of the sink device is set to an audio playback device, the sink device can display second video data different from the first video data, thereby preventing the user from feeling uncomfortable. Thus, the audio playback device can prevent the user from feeling uncomfortable by suppressing the impact of video data transmitted from the source device to the sink device on the quality of audio played back by the source device after receiving the ARC signal, while preventing the user from feeling uncomfortable.

[0026] (6) The audio reproduction device according to (5), wherein the second video data is a signal representing a video in which all pixels are black.

[0027] According to the above aspect, since the image based on the second video data is an image in which all pixels are black, it is possible to suppress the sense of incongruity that a user may feel when viewing the image based on the first video data (for example, an image in which all pixels are green). Thus, the audio playback device can easily suppress the sense of incongruity that the user may feel when viewing the image based on the first video data, and can suppress the influence of the video data transmitted from the source device to the sink device on the quality of the audio that the source device receives and plays back after receiving the ARC signal.

[0028] (7) The audio reproduction device according to (5), wherein the second video data is a signal representing a predetermined video.

[0029] According to the above aspect, since the video based on the second video data is a predetermined video, it is possible to prevent the user from feeling uncomfortable when viewing the video. Thus, the audio playback device can easily prevent the user from feeling uncomfortable, while suppressing the influence of the video data transmitted from the source device to the sink device on the quality of the audio played back by the source device after receiving the ARC signal.

[0030] (8) A control method for an audio playback device that is a source device connected to a sink device in accordance with the HDMI standard, the control method including receiving an ARC signal from the sink device and transmitting, to the sink device, first video data in which all bits of pixel data have the same value in Y / Cb / Cr format when the ARC signal is received.

[0031] According to the above aspect, the same effects as those of the above audio playback device are achieved.

[0032] (9) A program that causes a computer to execute the control method described in (8).

[0033] According to the above aspect, the same effects as those of the above audio playback device are achieved.

[0034] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of well-known matters or redundant explanation of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0035] The inventor(s) provide the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and do not intend for them to limit the subject matter described in the claims.

[0036] (Embodiment) In this embodiment, an audio playback device or the like that suppresses the influence of video data transmitted from a source device to a sink device on the quality of audio that the source device receives and plays back after receiving an ARC signal will be described.

[0037] [1 System 1 Configuration] FIG. 1 is an explanatory diagram showing a system 1 according to the present embodiment.

[0038] 1, system 1 includes at least a source device 10 and a sink device 30. System 1 may further include a source device 20. Here, an example will be described in which there are two source devices, but the number of source devices may be one or more than two.

[0039] The source device 10 and the sink device 30, and the source device 10 and the source device 20 are connected by HDMI cables and perform communication in accordance with the HDMI standard.

[0040] [1-1 Configuration of source device 10] The source device 10 can transmit video data and audio data to the sink device 30. The source device 10 has a port 1A, which is an HDMI port, and is connected to the sink device 30 via the port 1A by an HDMI cable. The port 1A supports ARC. In other words, the port 1A can receive an ARC signal, and the received ARC signal is processed by the source device 10.

[0041] The source device 10 communicates with the sink device 30 in accordance with the HDMI standard via an HDMI cable. The source device 10 also receives an ARC signal from the sink device 30 and outputs audio based on the received ARC signal. The source device 10 is, for example, an audio amplifier, a sound bar, or a speaker with a built-in amplifier.

[0042] The source device 10 includes an HDMI communication circuit 11, a processor 12, a video and audio processing circuit 13, and an audio output circuit 14. The HDMI communication circuit 11, the processor 12, the video and audio processing circuit 13, and the audio output circuit 14 may be partially or entirely realized by a CPU (Central Processing Unit) included in the source device 10 executing a program stored in a memory.

[0043] The HDMI communication circuit 11 transmits a signal conforming to the HDMI standard to the sink device 30 via the port 1A. The HDMI communication circuit 11 also receives a signal conforming to the HDMI standard from the sink device 30 via the port 1A.

[0044] The HDMI communication circuit 11 includes an encoder 15 and an ARC receiving circuit 16.

[0045] Encoder 15 transmits a TMDS signal (also referred to as a video and audio signal) to sink device 30 in accordance with the HDMI standard. The TMDS signal includes digital video data (also referred to as video data), digital audio data (also referred to as audio data), and control information indicating the resolution of the video data and the sample rate of the audio data. Encoder 15 generates a TMDS signal by encoding (i.e., coding) the video data and audio data provided by video and audio processing circuit 13, and transmits the generated TMDS signal to sink device 30.

[0046] The ARC receiving circuit 16 receives an ARC signal from the sink device 30 in accordance with the HDMI standard. The ARC signal includes audio data. The ARC receiving circuit 16 provides the received ARC signal to the video and audio processing circuit 13. The ARC receiving circuit 16 is an example of an ARC receiving unit.

[0047] The processor 12 controls circuits and the like included in the source device 10. Specifically, the processor 12 performs processing related to control between the source device 10 and the sink device 30. The processor 12 performs the processing related to the control by transmitting and receiving a CEC (Consumer Electronics Control) signal. For example, the processor 12 transmits a signal indicating the operation of the source device 10 or a signal controlling the operation of the sink device 30 to the sink device 30 as a CEC signal. The processor 12 also receives a signal indicating the operation of the sink device 30 or a signal controlling the operation of the source device 10 from the sink device 30 as a CEC signal. More specifically, the CEC signal includes a signal indicating switching of the signal source of the sink device 30 as a signal indicating the operation of the sink device 30. The processor 12 receives the CEC signal from the sink device 30, thereby receiving the signal indicating switching of the signal source of the sink device 30.

[0048] The processor 12 can also control the operation of the video and audio processing circuit 13 (specifically, the transmission of video data or audio data).

[0049] The video and audio processing circuit 13 performs processing related to video and audio. The video and audio processing circuit 13 generates video data and audio data indicating video and audio to be transmitted to the sink device 30, and transmits the generated video data and audio data to the sink device 30 by providing the generated video data and audio data to the HDMI communication circuit 11 (specifically, the encoder 15). The video and audio processing circuit 13 also receives an ARC signal transmitted by the sink device 30 via the HDMI communication circuit 11 (specifically, the ARC receiving circuit 16). When the video and audio processing circuit 13 receives an ARC signal, it generates audio data based on the received ARC signal and provides the audio data to the audio output circuit 14. The operation of the video and audio processing circuit 13 can be controlled by the processor 12. The video and audio processing circuit 13 is an example of a video processing unit.

[0050] When the ARC receiving circuit 16 receives an ARC signal, the video and audio processing circuit 13 transmits video data (also referred to as first video data) in which all bits of pixel data have the same value in Y / Cb / Cr format to the sink device 30. More specifically, the first video data is video data in which pixel data is expressed in Y / Cb / Cr format as Y=0x00, Cb=0x00, and Cr=0x00. This corresponds to the case where the above-mentioned "same value" is 0. Note that the above-mentioned pixel data shows green when displayed on the display panel 34. Note that "0x" indicates a hexadecimal number.

[0051] This suppresses fluctuations in the bit values ​​of the video data input to the HDMI communication circuit 31 of the sink device 30, which contributes to suppressing noise that may be generated by the circuit.

[0052] In addition to the above, the first video data may be video data in which pixel data is expressed in Y / Cb / Cr format as Y=0xff, Cb=0xff, Cr=0xff. This corresponds to the case where the above-mentioned "same value" is 1. However, in the decoding process of the video data, pixel data expressed as Y=0x00, Cb=0x00, Cr=0x00 may be added to an area outside the area corresponding to the pixels that make up the video. In such a case, using video data in which pixel data is expressed as Y=0x00, Cb=0x00, Cr=0x00 results in even smaller fluctuations in the bit values ​​input to the HDMI communication circuit 31 of the sink device 30. In addition, the area outside the area corresponding to the pixels that make up the video may be an area corresponding to a blanking period.

[0053] The video / audio processing circuit 13 may transmit, as the first video data, video data that satisfies at least one of the following conditions: a resolution of 480p or 576p; a color format of Y / Cb / Cr=4:2:2 or 4:2:0; a deep color setting that is disabled; and a pixel repetition setting that is disabled. Here, the deep color setting and the pixel repetition setting are setting items that can be described in EDID (Extended Display Identification Data) in the HDMI standard. This can further contribute to suppressing fluctuations in the bit value of the video data input to the HDMI communication circuit 31 of the sink device 30.

[0054] The video and audio processing circuit 13 can determine the value included in the first video data according to the color format supported by the sink device 30. That is, the video and audio processing circuit 13 determines whether the sink device 30 supports the color format of Y / Cb / Cr=4:2:2 or 4:2:0, and can transmit the first video data having 0 as the same value only when it is determined that the sink device 30 supports the color format.

[0055] The video / audio processing circuit 13 can also change the video data to be transmitted to the sink device 30 in accordance with the CEC signal received by the processor 12. The CEC signal corresponds to a switching signal indicating that the signal source of the sink device 30 is to be switched. That is, when the video / audio processing circuit 13 receives a switching signal indicating that the signal source of the sink device 30 is to be switched to the source device 10, it can transmit video data (also referred to as second video data) different from the first video data to the sink device 30. The second video data may be a signal indicating a video in which all pixels are black, or may be a signal indicating a predetermined video. Note that, in the Y / Cb / Cr format, black pixels are expressed as Y=0x10, Cb=0x80, and Cr=0x80. The processing of the video / audio processing circuit 13 will be described in detail later.

[0056] The audio output circuit 14 reproduces audio by outputting an audio signal to the speaker 19. The audio output circuit 14 has an amplifier (not shown) and amplifies the audio reproduced by the amplifier. When audio data based on the ARC signal from the sink device 30 is provided from the video / audio processing circuit 13, the audio output circuit 14 converts the provided audio data into an audio signal, provides the audio signal to the speaker 19 after being amplified by the amplifier, and causes the speaker 19 to reproduce the audio. Note that the speaker 19 may be a speaker located outside the source device 10 as shown in FIG. 1, or may be a speaker (not shown) provided in the source device 10.

[0057] The source device 20 can transmit video and audio to the sink device 30. The source device 20 has port 2A, which is an HDMI port, and is connected to the sink device 30 via port 2A with an HDMI cable. Port 2A does not support ARC. In other words, port 2A cannot receive an ARC signal, or even if it can receive one, the received ARC signal will not be processed.

[0058] [1-2 Configuration of source device 20] The source device 20 communicates with the sink device 30 in accordance with the HDMI standard via an HDMI cable. The source device 20 is, for example, a recording device (specifically, a Blu-ray (registered trademark) recorder or a DVD recorder, etc.) or a playback device (specifically, a Blu-ray player or a DVD player, etc.).

[0059] The source device 20 includes an HDMI communication circuit 21, a processor 22, a video and audio processing circuit 23, and a storage 24. The HDMI communication circuit 21, the processor 22, and the video and audio processing circuit 23 may be partially or entirely realized by a CPU (Central Processing Unit) included in the source device 20 executing a program stored in a memory.

[0060] The HDMI communication circuit 21 transmits a signal conforming to the HDMI standard to the sink device 30 via the port 2A. The HDMI communication circuit 21 also receives a signal conforming to the HDMI standard from the sink device 30 via the port 2A.

[0061] The HDMI communication circuit 21 includes an encoder 25. The encoder 25 is similar to the encoder 15 included in the source device 10, and therefore a detailed description thereof will be omitted.

[0062] The processor 22 controls circuits and the like included in the source device 20. Specifically, the processor 22 performs processing related to control between the source device 20 and the sink device 30 by transmitting and receiving a CEC signal to and from the sink device 30. This processing is similar to the processing executed by the processor 12 included in the source device 10, and therefore a detailed description thereof will be omitted.

[0063] The processor 22 also controls the operation of the video and audio processing circuit 23 to acquire video data and audio data from the storage 24 .

[0064] The video and audio processing circuit 23 performs processing related to video and audio. Under the control of the processor 22, the video and audio processing circuit 23 acquires video data and audio data indicating video and audio to be transmitted to the sink device 30 from the storage 24. The video and audio processing circuit 23 then transmits the acquired video and audio data to the sink device 30 by providing it to the HDMI communication circuit 21 (specifically, the encoder 25). However, the video and audio processing circuit 23 does not perform processing when an ARC signal is received. This is because the port 2A does not support ARC.

[0065] The storage 24 is a storage device that stores video data and audio data. The storage 24 stores video data and audio data that the source device 20 is to transmit to the sink device 30, and the video and audio processing circuit 23 reads the data. The storage 24 is a Blu-ray disc drive in which a Blu-ray disc is inserted, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like.

[0066] [1-3 Configuration of sink device 30] Sink device 30 receives video data and audio data from source device 10 or source device 20, displays video related to the video data on display panel 34, and outputs audio related to the audio data from source device 10. Sink device 30 has ports 3A and 3B which are HDMI ports, and is connected to source device 10 via HDMI port 3A with an HDMI cable, and is connected to source device 20 via HDMI port 3B with an HDMI cable. Port 3A supports ARC. Port 3B does not need to support ARC.

[0067] The sink device 30 communicates with the source device 10 and the source device 20 via an HDMI cable in accordance with the HDMI standard.

[0068] The sink device 30 can switch the signal source based on an operation by the user. A source that provides video data related to video displayed by the sink device 30 and audio data related to audio output by the sink device 30 is called a signal source. The signal source is selected from a plurality of source devices (i.e., source devices 10 and 20), tuners (for example, a tuner that receives terrestrial broadcasts or a tuner that receives satellite broadcasts), storage, etc. connected to the sink device 30. The sink device 30 is, for example, a television receiver.

[0069] The sink device 30 includes an HDMI communication circuit 31, a processor 32, a video and audio processing circuit 33, and a display panel 34. The HDMI communication circuit 31, the processor 32, and the video and audio processing circuit 33 may be partially or entirely realized by a CPU included in the sink device 30 executing a program stored in a memory.

[0070] The HDMI communication circuit 31 receives signals conforming to the HDMI standard (including TMDS signals and CEC signals) from source devices 10 and 20 via ports 3A and 3B, respectively. The HDMI communication circuit 31 also transmits signals conforming to the HDMI standard (including ARC signals) to source device 10 via port 3A.

[0071] The HDMI communication circuit 31 includes a decoder 35 and an ARC transmission circuit 36.

[0072] The decoder 35 receives TMDS signals from the source devices 10 and 20 in accordance with the HDMI standard. The decoder 35 obtains video data and audio data by decoding one of the received TMDS signals that is selected as a signal source. The decoder 35 then provides the obtained video data and audio data to the video / audio processing circuit 33. The signal source is selected under the control of the processor 32, either by a user operation or when a CEC signal is received.

[0073] The ARC transmission circuit 36 ​​transmits an ARC signal to the source device 10 in accordance with the HDMI standard. The ARC transmission circuit 36 ​​transmits the audio signal provided from the video and audio processing circuit 33 as an ARC signal to the source device 10. When a storage or a tuner is selected as the signal source, an audio signal received by the tuner or an audio signal stored in the storage is provided from the video and audio processing circuit 33 to the ARC transmission circuit 36, and the ARC transmission circuit 36 ​​transmits the audio signal thus provided to the source device 10 as an ARC signal.

[0074] The processor 32 controls circuits and the like included in the sink device 30. The processor 32 also performs processing related to control between the source devices 10 and 20 and the sink device 30. The processor 32 performs the above-mentioned control processing by transmitting and receiving CEC signals. For example, the processor 32 transmits a signal indicating the operation of the sink device 30 or a signal controlling the operation of the source device 10 or 20 as a CEC signal to the source devices 10 and 20. The processor 32 also receives a signal indicating the operation of the source device 10 or 20 or a signal controlling the operation of the sink device 30 from the source device 10 or 20 as a CEC signal. Specifically, when switching the signal source, the processor 32 transmits a signal indicating the operation of the sink device 30 and a signal indicating the switching of the signal source of the sink device 30 as a CEC signal to the source devices 10 and 20.

[0075] The processor 32 also performs processing related to the selection of a signal source for the sink device 30. Specifically, the processor 32 performs processing when a user operates the switch 37. The above operation includes an operation to select a signal source. When an operation to select a signal source is performed, the processor 32 determines the signal source from the details of the operation. Then, when the determined signal source is either the source device 10 or 20, the processor 32 sets the determined signal source in the HDMI communication circuit 31. When the processor 32 receives control to change the signal source via a CEC signal, the processor 32 sets the signal source in the HDMI communication circuit 31 in accordance with the control.

[0076] The video and audio processing circuit 33 performs processing related to video and audio.

[0077] When the signal source is either source device 10 or 20, video and audio processing circuit 33 acquires the video data and audio data acquired by decoding by decoder 35. When the signal source is a tuner or storage, video and audio processing circuit 33 acquires the video data and audio data from the tuner or storage. From the acquired video data, video and audio processing circuit 33 calculates pixel values ​​of multiple pixels that make up the video, and provides information indicating the pixel values ​​to display panel 34, thereby causing the display panel 34 to display a video based on the video data.

[0078] Furthermore, the video and audio processing circuit 33 provides the acquired audio data to the HDMI communication circuit 31, thereby providing it to the source device 10 as an ARC signal, and causes the source device 10 to reproduce audio based on the audio data.

[0079] Depending on the configuration of the circuits constituting the video and audio processing circuit 33, the video and audio processing circuit 33 may generate noise due to the received video data, and the noise may be superimposed on the ARC signal. For example, the circuit generates noise due to temporal fluctuations in the bit values ​​of the video data input to the circuit. In this case, for example, it may be possible to reduce or eliminate the generated noise by reducing or eliminating the temporal fluctuations in the bit values ​​of the video data.

[0080] For example, video data in which all bits of pixel data contained in the video data have the same value in the Y / Cb / Cr format has relatively small fluctuations in the bit values ​​of the video data over time.

[0081] Furthermore, when the same value is 0, temporal fluctuations in the bit values ​​of the video data may become even smaller.Furthermore, when at least one of the following conditions is satisfied: the resolution is 480p or 576p, the color format is Y / Cb / Cr=4:2:2 or 4:2:0, the deep color setting is disabled, and the pixel repetition setting is disabled, temporal fluctuations in the bit values ​​of the video data may become even smaller.

[0082] The display panel 34 displays an image. The display panel 34 acquires information including pixel values ​​of a plurality of pixels from the video / audio processing circuit 33, and displays an image based on the acquired information.

[0083] The switch 37 receives a user operation on the sink device 30. The switch 37 is provided on the housing of the main body of the sink device 30 or on a remote control for the sink device 30. The switch 37 may be a button, a slide switch, or the like. When the switch 37 receives a user operation, it provides information indicating the operation content to the processor 32.

[0084] [2 Signals transmitted and received between source devices 10 and 20 and sink device 30] Fig. 2 is a first explanatory diagram showing signals transmitted and received between source devices 10 and 20 and sink device 30 in system 1 according to the present embodiment. Note that Fig. 2 illustrates some of the components in Fig. 1 that are related to the transmission and reception of the signals.

[0085] 2 shows signals transmitted and received between source devices 10 and 20 and sink device 30 when sink device 30 selects source device 20 as a signal source. The figure shows a state in which sink device 30 decodes a video / audio signal 42 received from source device 20 using decoder 35, displays video data processed by video / audio processing circuit 33, and transmits the audio data processed by video / audio processing circuit 33 in an ARC signal 43 from ARC transmission circuit 36.

[0086] 2, the source device 10 transmits a video and audio signal 41 to the sink device 30, and the transmitted video and audio signal 41 is received by the sink device 30. The source device 20 transmits a video and audio signal 42 to the sink device 30, and the transmitted video and audio signal 42 is received by the sink device 30. The sink device 30 transmits an ARC signal 43 to the source device 10, and the transmitted ARC signal 43 is received by the source device 10.

[0087] In this way, when the source device 10 receives the ARC signal 43 in a state where the signal source of the sink device 30 is not the source device 10, the source device 10 transmits the first video data as the video and audio signal 41.

[0088] Fig. 3 is a second explanatory diagram showing signals transmitted and received between source devices 10 and 20 and sink device 30 in system 1 according to the present embodiment. Like Fig. 2, Fig. 3 illustrates some of the components in Fig. 1 that are related to the transmission and reception of the signals.

[0089] FIG. 3 shows signals transmitted and received between the source devices 10 and 20 and the sink device 30 in a state in which the sink device 30 has selected the source device 10 as a signal source.

[0090] 3, the source device 10 transmits a video and audio signal 44 to the sink device 30, and the transmitted video and audio signal 44 is received by the sink device 30. The source device 20 transmits a video and audio signal 45 to the sink device 30, and the transmitted video and audio signal 45 is received by the sink device 30. The sink device 30 transmits an ARC signal 46 to the source device 10, and the transmitted ARC signal 46 is received by the source device 10.

[0091] In this way, in a state where the signal source of the sink device 30 is the source device 10, the source device 10 transmits the second video data as the video and audio signal 44. Here, the video and audio signal 44 includes silent audio data as the audio data, or does not include any audio data.

[0092] [3 Processing performed by source device 10] FIG. 4 is a flowchart showing the flow of processing executed by source device 10 in system 1 according to the present embodiment.

[0093] 4 is performed when the ARC receiving circuit of the source device 10 receives an ARC signal after an HDMI connection between the source device 10 and the sink device 30 and an HDMI connection between the source device 20 and the sink device 30 have been established. The process related to establishing an HDMI connection includes processes such as detecting a Hot Plug Detect (HPD) signal, providing EDID, and setting the ARC function. The EDID includes information indicating a color format. When an HDMI connection between the source device 20 and the sink device 30 is established, the source device 20 and the sink device 30 each transmit and receive EDID to obtain the corresponding color format.

[0094] In step S100, the processor 12 determines whether or not RGB is the only color format supported by the sink device 30. If it is determined that RGB is the only color format supported by the sink device 30 (Yes in step S101), the process proceeds to step S104, and if not (in other words, if the sink device 30 supports at least one of the color formats Y / Cb / Cr) (No in step S101), the process proceeds to step S101.

[0095] In step S101, the processor 12 determines whether or not the signal source of the sink device 30 is the source device 10. Whether or not the signal source of the sink device 30 is the source device 10 can be determined using information indicating the current signal source of the sink device 30, which is obtained from a CEC signal (equivalent to a switching signal) that is received by the source device 10 and indicates switching of the signal source of the sink device 30. If it is determined that the signal source of the sink device 30 is the source device 10 (Yes in step S101), the process proceeds to step S102, and if not (No in step S101), the process proceeds to step S103.

[0096] In step S102, the processor 12 sets the color format of the video that the video and audio processing circuit 13 transmits to the sink device 30 to one of the Y / Cb / Cr color formats supported by the sink device 30. An example of the color format to be set is Y / Cb / Cr=4:2:2 or 4:2:0. The processor 12 also controls the video and audio processing circuit 13 to transmit to the sink device 30 video data (corresponding to the second video data) in which all pixels included in the video data have Y=0x10, Cb=0x80, and Cr=0x80.

[0097] The color formats that can be set by the processor 12 include Y / Cb / Cr=4:4:4, 4:2:2, and 4:2:0. Here, these color formats are referred to as the "444 format," the "422 format," and the "420 format," respectively.

[0098] Of the three formats, the amount of data transmitted from the source device 10 to the sink device 30 (the amount of TMDS signal communication) is the largest for the 444 format, the smallest for the 420 format, and somewhere in between for the 422 format. From the perspective of reducing noise in the video being played back, it is desirable to transmit a smaller amount of data. Therefore, from the perspective of reducing the amount of data transmitted from the source device 10 to the sink device 30, it is most desirable for the processor 12 to select the 420 format from the three formats. Furthermore, if the sink device 30 supports the 422 format or the 420 format in addition to the 444 format, it is desirable for the processor 12 to select the 422 format or the 420 format as the color format.

[0099] Furthermore, in the case of the 420 format, the HDMI communication circuit 31 of the sink device 30 that receives video data in the 420 format may perform conversion processing to one of Y / Cb / Cr color formats (for example, the 422 format). In contrast, in the case of the 422 format or the 444 format, the HDMI communication circuit 31 of the sink device 30 that receives video data in that format does not need to perform color format conversion processing. If the HDMI communication circuit 31 performs color format conversion processing, the processing within the HDMI communication circuit 31 increases, which may result in more noise being generated due to changes in the bit values ​​of the data. Therefore, if the processor 12 selects the 422 format or the 444 format, the generation of the above noise can be suppressed. Therefore, from the perspective of suppressing the generation of noise due to the color format conversion processing while reducing the amount of data transmitted from the source device 10 to the sink device 30, it is desirable for the processor 12 to select the 422 format from the above three formats.

[0100] The processor 12 can also set the color format in consideration of at least one of the color format compatibility status of the sink device 30 and the actual noise occurrence status.

[0101] In step S103, the processor 12 sets the color format of the video that the video and audio processing circuit 13 transmits to the sink device 30 to one of the Y / Cb / Cr color formats supported by the sink device 30. An example of the color format to be set is Y / Cb / Cr=4:2:2 or 4:2:0. The processor 12 also controls the video and audio processing circuit 13 to transmit to the sink device 30 video data in which all pixels included in the video data have Y=0x00, Cb=0x00, and Cr=0x00 (corresponding to first video data). Note that the color format that the processor 12 sets is the same as in step S102. For example, if the sink device 30 supports the 422 format or the 420 format in addition to the 444 format, it is desirable that the processor 12 selects the 422 format or the 420 format as the color format.

[0102] In step S104, the processor 12 sets the color format of the video that the video and audio processing circuit 13 transmits to the sink device 30 to the RGB color format. The processor 12 also controls the video and audio processing circuit 13 to transmit to the sink device 30 video data in which all pixels included in the video data are R=0x00, G=0x00, and B=0x00.

[0103] [4 Processing performed by System 1] Fig. 5 is a sequence diagram showing the flow of a first process executed by the system 1 in this embodiment. In Fig. 5, the same processes as those shown in Fig. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0104] FIG. 5 shows the flow of processing when the sink device 30 switches the signal source to the source device 20 when the sink device 30 supports the color format of Y / Cb / Cr=4:2:2.

[0105] In step S201, the sink device 30 transmits a CEC signal indicating that the signal source is to be switched to the source device 20. The transmission of the CEC signal may be triggered, for example, by a user's operation on the sink device 30 to switch the signal source to the source device 20.

[0106] In step S202, the sink device 30 switches the signal source to the source device 20.

[0107] In step S201, source device 10 receives the signal transmitted by sink device 30. Then, based on receiving the signal, source device 10 transmits video data (corresponding to first video data) in Y / Cb / Cr color format with all pixels set to Y=0x00, Cb=0x00, and Cr=0x00 to sink device 30 (No in steps S100, No in S101, and S103).

[0108] In step S203, the sink device 30 displays an image on the display panel 34 based on the image data received from the source device 20.

[0109] In step S204, the sink device 30 transmits the audio signal received from the source device 20 to the source device 10 as an ARC signal.

[0110] In step S111, the source device 20 receives the ARC signal transmitted by the sink device 30 in step S204, and reproduces audio through the speaker 19 based on the received ARC signal.

[0111] The processes of steps S112 and S113 of the source device 10 and the processes of steps S203 and S204 of the sink device 30 (that is, the processes indicated by the dashed line frames in FIG. 5) are continuously executed.

[0112] In this way, the source device 10 transmits the first video data (step S103), whereby noise contained in the ARC signal transmitted by the sink device 30 is suppressed, and as a result, noise contained in the audio reproduced by the source device 10 is suppressed.

[0113] Fig. 6 is a sequence diagram showing the flow of a second process executed by the system 1 in this embodiment. In Fig. 6, the same processes as those shown in Fig. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0114] FIG. 6 shows the flow of processing when the sink device 30 switches the signal source to the source device 10.

[0115] In step S211, the sink device 30 transmits a CEC signal indicating that the signal source is to be switched to the source device 10. The transmission of the CEC signal may be triggered, for example, by a user's operation on the sink device 30 to switch the signal source to the source device 10.

[0116] In step S212, the sink device 30 switches the signal source to the source device 10.

[0117] In step S211, source device 10 receives the signal transmitted by sink device 30. Then, based on receiving the signal, source device 10 transmits video data in which all pixels have Y=0x10, Cb=0x80, and Cr=0x80 (steps S100: No, S101: Yes, and S102).

[0118] In step S213, the sink device 30 displays an image on the display panel 34 based on the image data received from the source device 10.

[0119] The process of step S102 by the source device 10 and the process of S213 by the sink device 30 (that is, the process indicated by the dashed line frame in FIG. 6) are continuously executed.

[0120] In this way, the source device 10 transmits the second video data (step S102), thereby suppressing the sense of discomfort that the user may have due to the video displayed by the sink device 30. That is, since the user can view an video in which all pixels are black, it is possible to suppress the sense of discomfort that the user may have when viewing an video in which all pixels are green.

[0121] Note that, in the above embodiment, the system 1 is described as including the source devices 10 and 20, but the system 1 may also include only the source device 10 and the sink device 30. In this case, the source device 10 plays back video and audio acquired by receiving broadcasts or video and audio stored in the storage of the sink device 30. At this time, the signal source of the sink device 30 is set to a tuner that receives terrestrial broadcasts, a tuner that receives satellite broadcasts, or storage. Even in this configuration, noise included in the ARC signal transmitted by the sink device 30 is suppressed, and as a result, noise included in the audio played back by the source device 10 is suppressed.

[0122] As described above, the embodiments have been described as examples of the technology in the present disclosure, and for that purpose, the accompanying drawings and detailed description have been provided.

[0123] Therefore, the components shown in the accompanying drawings and detailed description may include not only essential components for solving the problem, but also components that are not essential for solving the problem in order to illustrate the above implementation. Therefore, the fact that these non-essential components are shown in the accompanying drawings or detailed description should not be interpreted as immediately indicating that these non-essential components are essential.

[0124] Furthermore, since the above-described embodiments are intended to illustrate the technology of the present disclosure, various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0125] This disclosure is applicable to source devices that support ARC. [Explanation of symbols]

[0126] 1 System 10, 20 Source equipment 11, 21, 31 HDMI communication circuit 12, 22, 32 processors 13, 23, 33 Video and audio processing circuit 14 Audio output circuit 15, 25 encoder 16 ARC receiving circuit 19 Speaker 1A, 2A, 3A, 3B ports 24 Storage 30 Sink Devices 34 Display panel 35 decoder 36 ARC transmission circuit 37 Switch 41, 42, 44, 45 Video and audio signals 43, 46 ARC signal

Claims

1. An audio playback device that is a source device connected to a sink device in accordance with the HDMI (High-Definition Multimedia Interface) standard, an ARC (Audio Return Channel) receiving unit that receives an ARC signal from the sink device; a video processing unit that transmits, to the sink device, first video data in which all bits of pixel data have the same value in a Y / Cb / Cr format when the ARC receiving unit receives the ARC signal. Audio playback device.

2. The video processing unit transmits the first video data having 0 as the same value.

2. The audio playback device according to claim 1.

3. The video processing unit converts the first video data into (a) The resolution is 480p or 576p; (b) the color format is Y / Cb / Cr=4:2:2 or 4:2:0; (c) the deep color setting is disabled, and (d) the pixel repetition setting is disabled; Transmit video data that satisfies at least one of the following conditions:

2. The audio playback device according to claim 1.

4. The audio playback device further comprises a processor; The processor: determining whether the sink device supports a color format of Y / Cb / Cr=4:2:2 or 4:2:0, and controlling the video processing unit to transmit the first video data having 0 as the same value only when it is determined that the sink device supports the color format; 2. The audio playback device according to claim 1.

5. The audio playback device further comprises a processor; The processor: When a switching signal indicating that the signal source of the sink device is to be switched to the audio playback device is received, the video processing unit is controlled to transmit second video data different from the first video data to the sink device.

5. The audio reproducing device according to claim 1.

6. The second image data is data representing an image in which all pixels are black.

6. The audio reproducing device according to claim 5.

7. The second video data is data showing a predetermined video.

6. The audio reproducing device according to claim 5.

8. A method for controlling an audio playback device that is a source device connected to a sink device in accordance with the HDMI standard, comprising: receiving an ARC signal from the sink device; When receiving the ARC signal, first video data in which all bits of pixel data have the same value in Y / Cb / Cr format is transmitted to the sink device. Control method.

9. A program that causes a computer to execute the control method according to claim 8.

Images