Video and audio transmission system

Abstract

An audio-video transmission system includes a multimedia device. The multimedia device includes a high-definition multimedia interface receiver, a first conversion circuit, and a first universal serial bus type-C interface. The first conversion circuit is configured to convert a first audio signal output from an audio channel pin of the high-definition multimedia interface receiver into a second audio signal in a universal serial bus type-C interface format. The first universal serial bus type-C interface is configured to transmit the second audio signal. The audio channel pin of the high-definition multimedia interface receiver is an audio return channel pin or an enhanced audio return channel pin.

Description

Technical Field

[0001] This invention relates to a transmission system, and more particularly to an audio-visual transmission system. Background Technology

[0002] The USB-C interface is becoming increasingly prevalent in audio-visual transmission systems. To improve user experience, its support for various formats is constantly expanding. For example, the USB-C interface features a display port alternate mode (DP ALT mode), which allows it to receive DP format audio and video data. Therefore, the need for USB-C interface support for other formats is also becoming increasingly important. Summary of the Invention

[0003] This invention discloses an audio-visual transmission system, comprising a multimedia device. The multimedia device includes a High Definition Multimedia Interface (HDMI) receiver, a first conversion circuit, and a first USB-C interface. The first conversion circuit converts a first audio signal output from the audio channel pin of the HDMI receiver into a second audio signal in Universal Serial Bus (USB) interface format. The first USB-C interface is used to transmit the second audio signal. The audio channel pin of the HDMI receiver is either an Audio Return Channel (ARC) pin or an Enhanced Audio Return Channel (eARC) pin.

[0004] This invention discloses an audio-visual transmission system, comprising a speaker and an amplifier. The amplifier includes a first USB-C interface and a first conversion circuit. The first USB-C interface is used to receive a first audio signal in Universal Serial Bus (USB) format via its USB 2.0 pins. The first conversion circuit is used to convert the first audio signal into a second audio signal in a universal audio format, enabling the speaker to play the second audio signal.

[0005] The audio-visual transmission system of the present invention utilizes the USB 2.0 pin in the USB-C interface to transmit the audio return signal output by the ARC pin or eARC pin of HDMI, enabling the USB-C interface of the audio-visual transmission system to support the audio return function of HDMI. Attached Figure Description

[0006] Various embodiments of the invention can be best understood by reading the following description and the accompanying drawings. It should be noted that, in accordance with standard practice in the art, the various features in the figures are not drawn to scale. In fact, the dimensions of certain features may be intentionally enlarged or reduced for clarity of description.

[0007] Figure 1 This is a schematic diagram of an audio-visual transmission system in some embodiments of the present invention.

[0008] Figure 2 This is a schematic diagram of a multimedia device and an amplifier in some embodiments of the present invention.

[0009] Figure 3 This is a schematic diagram of the USB-C interface pins in some embodiments of the present invention.

[0010] Figure 4 This is a schematic diagram of a multimedia device and an amplifier in other embodiments of the present invention. Detailed Implementation

[0011] Figure 1 This is a schematic diagram of an audio-visual transmission system 10 according to some embodiments of the present invention. The audio-visual transmission system 10 is used to receive audio-visual signals from audio-visual source 101 and / or audio-visual source 102, and to play video and / or audio based on the video source signal VI and the audio source signal AI in the audio-visual signals, wherein the video source signal VI and the audio source signal AI are mutually synchronized signals.

[0012] In some embodiments, the audio-visual transmission system 10 includes a multimedia device 100, an amplifier 200, and a speaker 300, but is not limited thereto.

[0013] In some embodiments, the audio / video signal is received from the audio / video source 101 by the amplifier 200. The amplifier 200 processes the audio / video signal to generate a video signal SV and an audio signal SA, and transmits the video signal SV and the audio signal SA to the multimedia device 100. The multimedia device 100 converts the video signal SV back into a video source signal VI and displays it. In some embodiments, the multimedia device 100 includes an HDMI receiver (e.g., illustrated on...). Figure 2(HDMI receiver 110). In HDMI format, multimedia device 100 can perform audio return function to amplifier 200 on the same transmission line, that is, multimedia device 100 returns audio signal SA to amplifier 200. Amplifier 200 then processes audio signal SA into audio signal SAO and transmits it to speaker 300. In this way, when multimedia device 100 displays video source signal VI, speaker 300 synchronously plays audio signal SAO, so that video and sound are played synchronously.

[0014] In other embodiments, the multimedia device 100 receives the audio / video signal from the audio / video source 102. The multimedia device 100 displays the video source signal VI. The multimedia device 100 also processes the audio source signal AI into an audio signal SA via the audio return function in HDMI format and transmits it to the amplifier 200. The amplifier 200 further processes the audio signal SA to generate an audio signal SAO and transmits it to the speaker 300, causing the speaker 300 to play the audio signal SAO.

[0015] The following example illustrates how amplifier 200 receives the audio-visual signal from audio-visual source 101. Figure 2 and Figure 4 An embodiment of the multimedia device 100 is provided. Figure 2 The multimedia device 100 includes an HDMI receiver 110, a USB-C (universal serial bus type C, USB-C) interface 120, and a conversion circuit 130. The conversion circuit 130 is coupled between the USB-C interface 120 and the HDMI receiver 110. The amplifier 200 includes a USB-C interface 210, a conversion circuit 220, a conversion circuit 230, and a conversion circuit 240. The USB-C interface 210 is coupled to both the conversion circuit 220 and the conversion circuit 230. The conversion circuit 230 is also coupled to the conversion circuit 240.

[0016] Amplifier 200 via other interfaces ( Figure 2 (Not shown) The present invention can receive audio and video signals (including video source signal VI and audio source signal AI) through interfaces such as HDMI, USB-C or DP, but is not limited thereto. Other suitable interfaces can also be used to receive audio and video signals.

[0017] like Figure 2As shown, the conversion circuit 230 converts the video source signal VI and the audio source signal AI into video signal SV1 and audio signal SA1 in DP interface format, which are then transmitted to the USB-C interface 210. The USB-C interface 210 has a DP replacement mode, therefore it can operate in DP replacement mode and supports DP interface format signal transmission. The USB-C interface 210 utilizes the high-speed data path pins (such as...) in the USB-C interface 210. Figure 3 The high-speed data channel pin (PHS) shown transmits the DP interface format video signal SV1 and the DP interface format audio signal SA1 to the multimedia device 100, and is received by the USB-C interface 120. Please also refer to... Figure 3 A schematic diagram of the USB-C interface pinout. The USB-C specification defines four pairs of high-speed data channel pins for the USB-C interface: TX1+, TX1-, RX1+, RX1-, TX2+, TX2-, RX2+, and RX2-. However, for ease of explanation, this invention uses the high-speed data channel pin PHS to represent the above four pairs of high-speed data channel pins.

[0018] The USB-C interface 120 in the multimedia device 100 also operates in DP alternative mode. The high-speed data channel pin PHS in the USB-C interface 120 is used to receive video signal SV1 and audio signal SA1, and then transmits the video signal SV1 and audio signal SA1 to the conversion circuit 130. The conversion circuit 130 is used to convert the video signal SV1 and audio signal SA1 from DP interface format to HDMI format video signal SV2 and audio signal SA2, and then transmit the video signal SV2 and audio signal SA2 to the HDMI receiver 110. After receiving the video signal SV2 and audio signal SA2, the HDMI receiver 110 displays the video signal SV2 and audio signal SA2 on the display screen (…). Figure 2 (Not shown) Displays image signal SV2. In some embodiments, image signal SV2 is substantially the same as image source signal VI.

[0019] In some embodiments, the HDMI receiver 110 conforms to the HDMI 1.4 specification and uses the Utility pin to transmit ARC signals, thereby providing audio return return functionality. In other embodiments, the HDMI receiver 110 conforms to the HDMI 2.1 specification and uses both the Utility pin and the HPD (hot plug detection) pin to transmit eARC signals, thereby providing enhanced audio return return functionality. However, the invention is not limited thereto, and the HDMI receiver 110 may conform to specifications higher than HDMI 2.1 and is backward compatible with both HDMI 2.1 and HDMI 1.4 specifications.

[0020] For ease of understanding, Figure 2 The multimedia device 100 and amplifier 200 illustrated are used to describe an embodiment of the HDMI receiver 110 conforming to the HDMI 1.4 specification. Figure 4 The multimedia device 100 and amplifier 200 illustrated are used to describe an embodiment of the HDMI receiver 110 conforming to the HDMI 2.1 specification, and the relevant operation is described below.

[0021] exist Figure 2 In the HDMI receiver 110, the Consumer Electronics Control (CEC) pin is used to output a control signal SC1. This control signal SC1 is used to obtain the audio formats supported by the amplifier 200 and to request or disable the amplifier 200's Audio Return Tracking (ART) function. After receiving the control signal SC1, the conversion circuit 130 converts it to a USB interface format control signal SC2 and transmits it to the USB-C interface 120. The USB-C interface 120 uses sidebands (see reference...). Figure 3 The amplifier 200 receives the control signal SC2 via the SBU (sideband use, SBU) pin PAU and transmits it to the USB-C interface 210 of the amplifier 200. The USB-C interface 210 also receives the control signal SC2 via the SBU pin PAU and transmits it to the conversion circuit 220. The conversion circuit 220 decodes the control signal SC2 to generate a control signal SC3, and transmits the control signal SC3 back to the conversion circuit 130 via the USB-C interface 210 and USB-C interface 120. The conversion circuit 130 further converts the control signal SC3 into an HDMI format control signal SC4 and transmits it to the HDMI receiver 110 via the CEC pin. The control signal SC4 is used to respond to the HDMI receiver 110 with the audio format supported by the amplifier 200, or to request the activation or deactivation of the audio return loop function.

[0022] After the HDMI receiver 110 receives the control signal SC4, it outputs an audio signal SA2 to the conversion circuit 130 via its ARC pin. The conversion circuit 130 converts the audio signal SA2 into a USB interface format audio signal SA3 and transmits it to the USB-C interface 120. The USB-C interface 120 receives the audio signal SA3 via its USB 2.0 pin PU2 and transmits it to the USB-C interface 210. The USB-C interface 210 also receives the audio signal SA3 via its USB 2.0 pin PU2 and transmits it to the conversion circuit 230. The conversion circuit 230 further converts the audio signal SA3 into an HDMI format audio signal SA4 and transmits it to the conversion circuit 240. In some embodiments, the audio signal SA4 is substantially the same as the audio signal SA2. The conversion circuit 240 converts the audio signal SA4 into an audio signal SAO and transmits it to the speaker 300, causing the speaker 300 to play the audio signal SAO. In some embodiments, conversion circuit 240 includes a digital-to-analog converter (not shown) for converting the digital audio signal SA4 into an analog audio signal SAO. In other embodiments, conversion circuit 230 converts the audio signal SA3 into an audio signal SA4 in a common audio format, and conversion circuit 240 then converts the audio signal SA4 to generate the audio signal SAO and transmits it to speaker 300.

[0023] The USB-C specification defines a pair of sideband-use pins for the USB-C interface, namely SBU1 and SBU2. However, for ease of explanation, this invention uses the SBU pin PAU to represent the aforementioned pair of sideband-use pins.

[0024] In some embodiments, the speaker 300 can directly play the audio signal SA4. In other words, the amplifier 200 does not include the conversion circuit 240.

[0025] Please refer to Figure 4In an embodiment where the HDMI receiver 110 conforms to the HDMI 2.1 specification, the HDMI receiver 110 outputs a control signal SC5 via the eARC pin using a common mode data channel (CMDC). The control signal SC5 is used to request the amplifier 200 to activate the audio return loop function, obtain the audio formats supported by the amplifier 200, and process audio latency. After receiving the control signal SC5, the conversion circuit 130 converts it to a USB 2.0 format control signal SC6 and transmits it to the USB-C interface 120. The USB-C interface 120 receives the control signal SC6 via the USB 2.0 pin PU2 and transmits it to the amplifier 200's USB-C interface 210 using the control transfer type defined by USB 2.0. The USB-C interface 210 also receives the control signal SC6 via the USB 2.0 pin PU2 and transmits it to the conversion circuit 230. Conversion circuit 230 decodes control signal SC6 to generate control signal SC7, and transmits control signal SC7 back to conversion circuit 130 via USB-C interface 210 and USB-C interface 120. Conversion circuit 130 also converts control signal SC7 into HDMI format control signal SC8 and transmits it to HDMI receiver 110, wherein control signal SC8 is used to indicate to HDMI receiver 110 that it agrees to start audio return-to-home function, the audio format supported by return amplifier 200, and audio delay.

[0026] After receiving the control signal SC8, the HDMI receiver 110 outputs the audio signal SA2 to the conversion circuit 130 via its eARC pin using the differential mode audio channel (DMAC) method. The conversion circuit 130 converts the audio signal SA2 into a USB 2.0 format audio signal SA3 and transmits it to the USB-C interface 120. The USB-C interface 120 receives the audio signal SA3 via its USB 2.0 pin PU2 and transmits it to the USB-C interface 210 using the synchronous transmission type defined by USB 2.0. The USB-C interface 210 also receives the audio signal SA3 via its USB 2.0 pin PU2 and transmits it to the conversion circuit 230. The conversion circuit 230 further converts the audio signal SA3 into a universal audio format audio signal SA4 and transmits it to the conversion circuit 240. Conversion circuit 240 is used to convert audio signal SA4 into audio signal SAO and transmit it to speaker 300, so that speaker 300 plays audio signal SAO. In some embodiments, conversion circuit 230 is used to convert audio signal SA3 into HDMI format and transmit it to conversion circuit 240.

[0027] In some embodiments, based on the control transmission defined by USB 2.0, the conversion circuit 230 obtains the desired time delay length between the displayed video signal SV2 and the audio signal SA3 received by the conversion circuit 230 according to the control signal SC6. The conversion circuit 230 delays the audio signal SA3 according to the time delay length to generate the audio signal SA4, and then sends the actual time delay length of the amplifier 200 back to the multimedia device 100 through the control signal SC7. In this way, the conversion circuit 230 can be used to control the timing of the speaker 300 playing the audio signal SA4, so that the audio signal SA4 and the video signal SV2 can be played synchronously.

[0028] Compared to Figure 2 Implementation examples, Figure 4The amplifier 200 does not include the conversion circuit 220. Specifically, when performing the enhanced audio return function of the HDMI 2.1 specification, both the control signal SC5 and the audio signal SA2 are output via the eARC pin. Therefore, the USB-C interface 120 only uses the USB 2.0 pin PU2 to receive the corresponding control signal SC6 and audio signal SA3. Correspondingly, the USB-C interface 210 also only uses the USB 2.0 pin PU2 to receive the control signal SC6 and audio signal SA3 and to transmit the control signal SC6 and audio signal SA3 to the conversion circuit 230. When performing the audio return function of the HDMI 1.4 specification, the control signal SC1 and audio signal SA2 are output via the CEC pin and the ARC pin, respectively. The USB-C interface 120 uses the SBU pin PAU and the USB 2.0 pin PU2 to receive the corresponding control signal SC2 and audio signal SA3, respectively. Correspondingly, the USB-C interface 210 also receives control signal SC2 and audio signal SA3 via the SBU pin PAU and the USB 2.0 pin PU2, respectively, and transmits control signal SC2 and audio signal SA3 to conversion circuits 220 and 230. Therefore, Figure 2 The amplifier 200 also includes a conversion circuit 220.

[0029] This application utilizes a USB-C interface to transmit data between the multimedia device 100 and the amplifier 200, which improves convenience and compatibility. At the same time, the solution of this application can perform audio return function without adding an external transmission line, that is, without increasing the cost.

[0030] The foregoing description briefly outlines the features of certain embodiments of the present invention, enabling those skilled in the art to more fully understand the various embodiments of the invention. Those skilled in the art will readily recognize that the present invention can serve as a basis for designing or modifying other processes and structures to achieve the same objectives and / or advantages as the embodiments described herein. Those skilled in the art should understand that these equivalent embodiments remain within the spirit and scope of the present invention, and various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 10: Audio-visual transmission system

[0033] 101: Audio and video source

[0034] 102: Audio / Video Source

[0035] 100: Multimedia devices

[0036] 110: HDMI receiver

[0037] 120: USB-C interface

[0038] 130: Conversion circuit

[0039] 200: Amplifier

[0040] 210: USB-C interface

[0041] 220: Conversion circuit

[0042] 230: Conversion Circuit

[0043] 240: Conversion circuit

[0044] 300: Speaker

[0045] AV: Audio / Video Signal

[0046] AI: Audio source signal

[0047] VI: Image source signal

[0048] SV: Image signal

[0049] SV1: Image signal

[0050] SV2: Image signal

[0051] SA: Audio signal

[0052] SA1: Audio signal

[0053] SA2: Audio signal

[0054] SA3: Audio signal

[0055] SA4: Audio signal

[0056] SAO: Audio signal

[0057] SC1: Control signal

[0058] SC2: Control signal

[0059] SC3: Control signal

[0060] SC4: Control signal

[0061] SC5: Control signal

[0062] SC6: Control signal

[0063] SC7: Control signal

[0064] SC8: Control signal

[0065] PHS: High-speed data channel pin

[0066] PU2: USB 2.0 pin

[0067] PAU: SBU pin

Claims

1. An audio-visual transmission system, comprising: Multimedia device, including: High-definition multimedia interface (HDMI) receiver; The first conversion circuit is used to convert the first audio signal output from the audio channel pin of the HDMI receiver into a second audio signal in Universal Serial Bus (USB) interface format; and A first Universal Serial Bus Type C (USB-C) interface is used to transmit the second audio signal, wherein the first USB-C interface operates in Display Interface (DP) override mode. This audio channel pin is the Enhanced Audio Return Channel (eARC) pin. The first conversion circuit is also used to convert the first control signal transmitted from the eARC pin of the HDMI receiver into a second control signal in the USB interface format. The first USB-C interface is based on the control defined by USB 2.0, and transmits the second control signal and the second audio signal through the USB 2.0 pins of the first USB-C interface. The audio-visual transmission system further includes a second conversion circuit and a second USB-C interface. The second USB-C interface is used to receive the second audio signal through its USB 2.0 pin. The second conversion circuit receives the second control signal through the USB 2.0 pin of the second USB-C interface and uses it to generate a third control signal based on the second control signal. The first conversion circuit receives the third control signal through the USB 2.0 pin of the first USB-C interface, and is also used to generate a fourth control signal based on the third control signal and transmit the fourth control signal to the HDMI receiver. After receiving the fourth control signal, the HDMI receiver transmits the first audio signal to the first conversion circuit through the eARC pin.

2. The audio-visual transmission system according to claim 1, wherein the HDMI receiver outputs the first control signal using a common-mode data channel (CMDC) and outputs the first audio signal using a differential-mode audio channel (DMAC).

3. The audio-visual transmission system according to claim 1, wherein the multimedia device is further configured to receive mutually synchronized video source signals and audio source signals, and the multimedia device is configured to display the video source signal, wherein the first audio signal is substantially the same as the audio source signal. The audio-visual transmission system also includes: speaker; and The amplifier includes: the second USB-C interface; The second conversion circuit is used to convert the second audio signal into a third audio signal and transmit it to the speaker, so that the speaker can synchronously play the third audio signal when the multimedia device displays the image source signal.

4. An audio-visual transmission system, comprising: speaker; and Amplifier, including: A first Universal Serial Bus Type C (USB-C) interface is provided for receiving a first audio signal in Universal Serial Bus (USB) interface format via the USB 2.0 pins of the first USB-C interface; and A first conversion circuit is used to convert the first audio signal into a second audio signal in a common audio format, so that the speaker can play according to the second audio signal. The audio-visual transmission system further includes a multimedia device, which includes: High-definition multimedia interface (HDMI) receiver; The second conversion circuit is used to convert the third audio signal output from the audio channel pin of the HDMI receiver into the first audio signal; and A second Universal Serial Bus Type C (USB-C) interface is used to transmit the first audio signal, wherein the second USB-C interface operates in Display Interface (DP) override mode. This audio channel pin is the Enhanced Audio Return Channel (eARC) pin. The second conversion circuit is also used to convert the first control signal transmitted from the eARC pin of the HDMI receiver into a second control signal in the USB interface format. The second USB-C interface is based on the control defined by USB 2.0, and transmits the second control signal and the first audio signal through the USB 2.0 pins of the second USB-C interface. The first conversion circuit receives the second control signal through the USB 2.0 pin of the first USB-C interface and uses it to generate a third control signal based on the second control signal. The second conversion circuit receives the third control signal through the USB 2.0 pin of the second USB-C interface, and is also used to generate a fourth control signal based on the third control signal and transmit the fourth control signal to the HDMI receiver. After receiving the fourth control signal, the HDMI receiver transmits the third audio signal to the second conversion circuit through the eARC pin.

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