Method for transmitting video signal containing Alpha channel based on high-definition multimedia interface, receiving method and related electronic equipment

Abstract

The invention discloses a method for transmitting a video signal containing an Alpha channel based on a high-definition multimedia interface, a receiving method and related electronic equipment, and relates to the technical field of digital video transmission. The method applied to the electronic equipment at the transmitting end comprises the following steps: acquiring to-be-transmitted video data with an RGB color signal and an Alpha channel signal; the RGB signal is converted into a YCbCr signal containing 8 bit Y, 4 bit Cb and 4 bit Cr; respectively filling YCbCr and Alpha channel signals into exclusive bearing intervals of the RGB three channels according to a preset mapping rule and a 24-bit width requirement, and generating to-be-sent data of which the single-frame total amount, the resolution and the time sequence are consistent with those of RGB4: 4: 4; and synchronous transmission of the video data to be transmitted is realized through a single interface. According to the scheme, the RGB color signals and the Alpha channel signals are synchronously transmitted through a single interface, and data integrity and transmission compliance are guaranteed.

Description

Technical Field

[0001] This application relates to the field of digital video transmission technology, and in particular to a method for transmitting video signals containing an Alpha channel based on a high-definition multimedia interface, a receiving method, and related electronic equipment. Background Technology

[0002] In the field of digital video transmission technology, video signals with an alpha transparency channel are a core technology for achieving multimedia presentation effects such as logo overlay, subtitles, lyrics embedding, and graphic packaging. They are widely used in professional scenarios such as video production, live streaming, and variety show / film playback. These alpha transparency channel video signals are typically generated by computer equipment and need to be stably transmitted to professional video processing hardware for subsequent compositing and output. High-Definition Multimedia Interface (HDMI) and DisplayPort (DP), as low-cost, highly compatible digital video transmission interfaces standard on current computers and various display terminals, have become the mainstream transmission links for cross-device high-definition video signal transmission due to their stable signal transmission capabilities and wide device adaptability. However, limited by the original standard definitions of the interfaces, the official protocols of HDMI and DP do not include the transmission format of the alpha channel, making it impossible to directly achieve integrated transmission of alpha transparency channel video signals, thus creating a technical obstacle to the construction of signal links in related multimedia scenarios.

[0003] To overcome the aforementioned transmission limitations, two mainstream solutions have emerged in the industry: one involves using dedicated boards or devices to split the video signal with the alpha channel into a standard video signal and a black-and-white format alpha channel signal, which are then transmitted separately through two HDMI or DP interfaces. The receiving end requires dual interfaces to integrate the signals. This solution not only requires the purchase of expensive dedicated hardware, cables, and power supplies, but also consumes a significant amount of interface resources on the receiving device, greatly increasing system setup costs and wiring complexity. The other solution uses a non-standard signal format with 2-4 times the original resolution, carrying both the video signal and the alpha channel in a single HDMI or DP interface. While this solution saves on the number of interfaces, it significantly increases transmission bandwidth requirements, and the non-standard resolution can easily cause compatibility issues between devices, making it unsuitable for general transmission scenarios. Therefore, how to achieve stable and low-cost transmission of video signals with the alpha channel through a single interface without modifying the physical and protocol layers of the HDMI and DP interfaces, or increasing signal resolution and transmission bandwidth, has become a pressing technical problem to be solved. Summary of the Invention

[0004] This application provides a method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface, a receiving method, and related electronic devices. It can achieve synchronous transmission of video signals corresponding to RGB color signals and video signals corresponding to alpha channel signals through a single interface without changing the physical layer and protocol layer of the high-definition multimedia interface. This saves the additional procurement cost of dedicated hardware, conserves the interface resources of the receiving device, and ensures the compatibility of signal transmission and pixel synchronization accuracy.

[0005] In a first aspect, embodiments of this application provide: a method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface. This application provides a method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface, applied to a transmitting electronic device. The high-definition multimedia interface is a digital video interface that supports the RGB4:4:4 transmission protocol. The method includes the following steps: Acquire the video data to be transmitted, which carries RGB color signals and Alpha channel signals; Convert the RGB color signal to a YCbCr format video signal; the YCbCr format video signal includes: 8-bit luminance component Y, 4-bit chrominance component Cb, and 4-bit chrominance component Cr. The YCbCr format video signal and the Alpha channel signal are filled into the RGB data to be transmitted in the RGB4:4:4 transmission protocol according to the mapping rules agreed upon in advance by the transmitting and receiving electronic devices, combined with the signal bit width requirements of the RGB4:4:4 transmission protocol of the high-definition multimedia interface (i.e., the dedicated carrying area of ​​the three color data channels of RGB (R channel bit0~7, G channel bit0~3 / Cb and bit4~7 / Cr, B channel bit0~7)). The total amount of data per frame, the resolution of video per frame and the transmission timing specified by the interface protocol are consistent with the RGB4:4:4 format. The data to be transmitted is transmitted to the receiving electronic device through a single high-definition multimedia interface, so as to achieve synchronous transmission of the video signal and the Alpha channel signal carried in the data to be transmitted.

[0006] This solution integrates the video signal and the alpha channel signal into the three dedicated channels of the RGB4:4:4 protocol, enabling synchronous transmission of a single high-definition multimedia interface without the need for additional interface or protocol expansion, thus reducing hardware costs and compatibility risks. At the same time, the single-frame parameters and timing of the data to be transmitted are consistent with the protocol format, ensuring transmission compliance and avoiding signal loss or distortion due to format mismatch, thus solving the problem of traditional single-interface difficulty in synchronously transmitting video and alpha channel signals.

[0007] In conjunction with the first aspect, in a first possible implementation of the first aspect, converting the RGB color signal into a YCbCr format video signal includes: converting the RGB color signal into a YCbCr4:2:2 format video signal.

[0008] This implementation adopts the industry-standard YCbCr4:2:2 format, whose 8-bit Y + 4-bit Cb + 4-bit Cr component bit width is adapted to the bit width allocation of subsequent channel padding, eliminating the need for additional bit width conversion and simplifying the data processing flow. At the same time, the YCbCr 4:2:2 format balances color reproduction and data compression efficiency, reducing transmission bandwidth pressure and improving overall transmission efficiency while ensuring video color quality.

[0009] In conjunction with the first aspect, in the second possible implementation of the first aspect, the mapping rules pre-agreed between the transmitting end and the receiving end include: based on the 8-bit channel bit order with bit0 as the least significant bit and bit7 as the most significant bit, the 8-bit luminance component Y is filled into the full bit width range of bit0~bit7 of the R channel, the 4-bit chrominance component Cr is filled into the high bit width range of bit4~bit7 of the G channel, the 4-bit chrominance component Cb is filled into the low bit width range of bit0~bit3 of the G channel, and the 8-bit Alpha channel signal is filled into the full bit width range of bit0~bit7 of the B channel; and the filling ranges of each component do not overlap in bit width, and the filling operation is only performed within the corresponding dedicated bearer range.

[0010] This implementation method ensures that component filling is non-overlapping and non-conflicting by clearly defining the channel and bit mapping rules for each component, thus avoiding interference between different signals. The 8-bit Y channel exclusively occupies the R channel to ensure the integrity of the luminance signal. The high and low bits of the G channel respectively carry Cb / Cr to achieve efficient integration of chrominance signals. The B channel exclusively occupies the Alpha signal to ensure that the transparency information is lossless. This provides a clear technical basis for the receiver to accurately extract components and improves the accuracy of signal transmission.

[0011] In conjunction with the first aspect, in the third possible implementation of the first aspect, the signal width of the RGB4:4:4 transmission protocol of the high-definition multimedia interface is 24 bits, and the total width of the dedicated bearer interval is consistent with the 24-bit signal width. The total width of the YCbCr format video signal is 16 bits, which is jointly carried by the full width interval of the R channel and the full width interval of the G channel. The 8-bit width of the Alpha channel signal is carried separately by the full width interval of the B channel, and the bit width allocation of each component corresponds completely to the component extraction interval preset by the receiver.

[0012] This implementation method precisely allocates a total bit width of 24 bits (16 bits YCbCr + 8 bits Alpha) to adapt to the bit width requirements of the RGB4:4:4 protocol, without bit width redundancy or insufficiency. At the same time, it clearly defines the correspondence between the component bit width and the extraction interval at the receiving end, forming a technical closed loop of "transmitting filling - receiving extraction", avoiding signal parsing errors caused by bit width mismatch, and ensuring the reliability and consistency of end-to-end transmission.

[0013] Secondly, embodiments of this application provide a method for receiving video signals containing an alpha channel based on a high-definition multimedia interface, applied to a receiving electronic device. The high-definition multimedia interface is a digital video interface that supports the RGB4:4:4 transmission protocol. The method includes the following steps: Through a single high-definition multimedia interface, following the transmission timing specified by the RGB4:4:4 transmission protocol, the transmitting end electronic device receives the data to be transmitted based on the method for transmitting video signals containing an Alpha channel via a high-definition multimedia interface as described in the first aspect or any possible implementation of the first aspect. According to the pre-agreed mapping rules between the transmitting and receiving electronic devices, combined with the 24-bit signal width requirement of the RGB4:4:4 transmission protocol and the fact that each of the R, G, and B color data channels is allocated 8 bits of width under this protocol, the YCbCr format video signal component and the Alpha channel signal component are extracted from the RGB three color data channels of the data to be transmitted. The extracted YCbCr format video signal components are reassembled into a complete YCbCr format video signal and then converted into RGB color signals. The RGB color signal is integrated with the extracted Alpha channel signal component to generate target video data carrying both RGB color signal and Alpha channel signal. The total data volume and resolution of a single frame of the target video data are consistent with the original video data to be transmitted by the transmitting electronic device.

[0014] This solution accurately extracts signal components from the RGB three channels through a mapping rule matched with the transmitter, achieving effective parsing of data transmitted through a single interface. The parameters of the target video data generated after color conversion and signal integration are consistent with the original data, ensuring lossless video quality. It solves the problem that traditional receivers have difficulty separating the Alpha channel information from the standard RGB4:4:4 signal, achieving complete restoration of video and transparency signals.

[0015] In conjunction with the second aspect, in the first possible implementation of the second aspect, the conversion to an RGB color signal includes: converting to an RGB color signal according to the YCbCr to RGB color space conversion formula specified in the Rec.709 high-definition video standard. The calculation results of the R, G, and B components of the conversion formula have a value range of 0~255 to match the 8-bit storage width of the RGB three-channel, and the input and output bit width of the formula is consistent with the specifications of the 8-bit luminance component Y and the 4-bit chrominance components Cb and Cr. The color conversion error meets the high-definition video color reproduction error threshold specified in the Rec.709 standard.

[0016] This implementation uses the Rec.709 high-definition standard for color conversion, ensuring that the converted RGB color signal meets the industry's high-definition video requirements; the value range of 0~255 matches the 8-bit storage width, avoiding color overflow or distortion; the input and output bit widths are consistent with the component specifications and strict error threshold constraints ensure the accuracy of color reproduction and improve the visual quality of the target video.

[0017] In conjunction with the second aspect, in the second possible implementation of the second aspect, the mapping rules pre-agreed between the transmitting electronic device and the receiving electronic device include: based on the 8-bit channel bit sequence with bit0 as the least significant bit and bit7 as the most significant bit, the full bit width range of bit0~bit7 of the R channel, the high bit width range of bit4~bit7 of the G channel, and the low bit width range of bit0~bit3 of the G channel are defined as the dedicated bearer range of the YCbCr format video signal, and the full bit width range of bit0~bit7 of the B channel is defined as the dedicated bearer range of the Alpha channel signal; and the dedicated bearer ranges of each component have no bit width overlap, and the extraction operation is only performed within the corresponding dedicated bearer range.

[0018] This implementation method ensures that the extraction operation is only for the target component by clearly defining the dedicated bearer interval and non-overlapping extraction constraints, thus avoiding signal mixing caused by cross-interval reading. The interval division rules that are completely consistent with those of the transmitting end ensure the accuracy of component extraction, lay a reliable foundation for subsequent signal reconstruction and integration, and reduce the parsing error rate.

[0019] In conjunction with the second aspect, in the third possible implementation of the second aspect, in the RGB three color data channels of the data to be transmitted, the full bit width range of R channel (bits 0-7), the high bit width range of G channel (bits 4-7), and the low bit width range of G channel (bits 0-3) are collectively limited to a 16-bit YCbCr format video signal dedicated carrier range. The full bit width range of B channel (bits 0-7) is separately limited to an 8-bit Alpha channel signal dedicated carrier range. The full bit width range of R channel is dedicated to carrying the luminance component Y, the high bit width range of G channel (bits 4-7) is dedicated to carrying the chrominance component Cr, and the low bit width range of G channel (bits 0-3) is dedicated to carrying the chrominance component Cb.

[0020] The YCbCr format video signal components and Alpha channel signal components are extracted separately, including: extracting the 8-bit luminance component Y from the full bit width range of the R channel, extracting the 4-bit chrominance component Cr from the high bit width range of bit 4 to bit 7 of the G channel, and extracting the 4-bit chrominance component Cb from the low bit width range of bit 0 to bit 3 of the G channel, which are then merged to form a 16-bit YCbCr format video signal component; and extracting the 8-bit Alpha channel signal component from the full bit width range of the B channel.

[0021] This implementation refines the extraction operation to specific bits through quantized component-interval correspondence, enabling precise reproduction of the component extraction process. The extraction specifications of 8-bit Y and 4-bit Cr / Cb perfectly match the fill bit width of the transmitting end, resulting in a highly complete 16-bit YCbCr signal after merging. The separate extraction of the Alpha signal from the B channel ensures the purity of the transparency information, ultimately achieving high-quality separation and restoration of the video and Alpha channel signals.

[0022] Thirdly, embodiments of this application provide an electronic device as a transmitting electronic device, including: a high-definition multimedia interface supporting the RGB4:4:4 transmission protocol, a processor, and a memory, wherein the processor is configured to execute computer-executable instructions; the memory stores one or more computer-executable instructions, which, when executed by the processor, implement the various steps of the method for transmitting a video signal containing an alpha channel based on a high-definition multimedia interface as described in the first aspect or any possible implementation of the first aspect.

[0023] This transmitting electronic device provides a physical carrier for the aforementioned transmission method through the combination of hardware (an interface supporting the RGB4:4:4 protocol) and software (computer instructions that execute the transmission method). The standard interface ensures the universality and compatibility of the device, while the configuration of the processor and memory guarantees the high efficiency of data processing and transmission. This enables the implementation of a technical solution for synchronous transmission of video and Alpha channel signals via a single interface, making it suitable for various video equipment scenarios that require the transmission of transparency information.

[0024] Fourthly, embodiments of this application provide an electronic device as a receiving electronic device, comprising: a high-definition multimedia interface supporting the RGB4:4:4 transmission protocol, a processor, and a memory, wherein the processor is configured to execute computer-executable instructions; the memory stores one or more computer-executable instructions, which, when executed by the processor, implement the various steps of the receiving method for parsing a video signal containing an Alpha channel based on a high-definition multimedia interface as described in the first aspect or any possible implementation of the first aspect.

[0025] The receiver electronic device achieves accurate parsing and signal restoration of the data transmitted from the transmitter through adapted hardware interfaces and software instructions; the standard RGB4:4:4 interface ensures seamless connection with the transmitter device; the processor's instruction execution capability ensures the efficient completion of steps such as component extraction and color conversion, and finally outputs a target video consistent with the original data, providing reliable hardware support for the reception and application of video containing alpha channels. Attached Figure Description

[0026] Figure 1A This is a schematic diagram illustrating the principle of a single HDMI interface transmitting only RGB video signals (excluding the alpha channel) in existing technology. Figure 1B This is a schematic diagram illustrating the principle of transmitting video signals and Alpha channel signals separately through dual HDMI interfaces in existing technology; Figure 2 This is a schematic flowchart of a method for transmitting video signals containing an Alpha channel based on a high-definition multimedia interface in one embodiment of this application; Figure 3 This is a schematic flowchart of a method for receiving video signals containing an Alpha channel based on a high-definition multimedia interface in one embodiment of this application; Figure 4A This is a step-by-step processing diagram of the uncompressed original state of the video signal, the compression processing stage, and the fusion stage with the Alpha channel signal in one embodiment of this application; Figure 4B This is a schematic diagram of a system architecture for transmitting video signals containing an Alpha channel based on a high-definition multimedia interface according to an embodiment of this application; Figure 4C This is a schematic diagram of the process of transmitting video signals containing an Alpha channel based on a high-definition multimedia interface in one embodiment of this application; Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0028] It should be understood that "multiple" as mentioned in this application refers to two or more. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist, for example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, to facilitate a clear description of the technical solutions of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and that "first," "second," etc., do not necessarily imply differences.

[0029] In the field of digital video transmission, especially in professional scenarios such as video production and live streaming, video signal transmission with an alpha channel is a core requirement for achieving high-quality image and text overlay and virtual studio effects. High-definition multimedia interfaces such as HDMI have become mainstream transmission carriers due to their low cost and strong compatibility. For example... Figure 1A As shown, the conventional single HDMI interface in the existing technology can only realize the transmission of RGB 4:4:4 format video signals. After the RGB 4:4:4 signal generated by GPU rendering is sent through the HDMI interface, the receiving end will convert it into YCbCr 4:2:2 format for processing. The entire link can only carry basic video color information and cannot meet the transmission requirements of the Alpha channel, thus failing to meet the needs of professional graphic keying applications.

[0030] For scenarios requiring simultaneous transmission of video and the Alpha channel, existing technologies offer dual HDMI interface solutions, but these have significant drawbacks. For example... Figure 1BAs shown, this solution uses a dedicated dual-HDMI output graphics interface card to transmit the RGB 4:4:4 signal and Alpha signal generated by the GPU separately via two HDMI interfaces. The receiving end needs to be equipped with dual HDMI receiving modules to process them separately. This solution not only requires the purchase of expensive dedicated hardware, occupying twice the interface resources of the receiving device, but also leads to decreased system stability due to multiple cable transmissions, easily causing problems such as desynchronization between the video and Alpha signals. The core reason for the defects of the existing technical solution is that the native protocol of high-definition multimedia interfaces such as HDMI only defines the transmission specifications of video color signals in RGB or YCbCr format, without reserving space for carrying the Alpha channel. The dedicated hardware solution compensates for the protocol defect by "adding physical interfaces" in a crude way, without solving the fundamental problem at the interface protocol and data mapping level.

[0031] Addressing numerous pain points in existing technologies, this application proposes an innovative solution for transmitting video signals containing an alpha channel based on a high-definition multimedia interface. This solution leverages the RGB4:4:4 transmission protocol supported by the HDMI interface, converting the RGB color signal generated by the GPU into an 8-bit Y, 4-bit Cb, 4-bit Cr YCbCr 4:2:2 format. Then, using preset mapping rules, the YCbCr components and the alpha channel signal are precisely filled into the dedicated bit-width ranges of the three RGB color data channels, generating data to be transmitted conforming to the RGB4:4:4 protocol. Finally, synchronous transmission of the video and alpha signals is achieved through a single HDMI port. This solution requires no additional hardware or bandwidth expansion, ensuring full compatibility with existing interface protocols while achieving lossless transmission of the alpha channel. It significantly reduces system costs, improves transmission stability and signal synchronization, and provides an efficient and low-cost solution for professional video production, live streaming, and other scenarios.

[0032] The embodiments of this application will now be described with reference to the accompanying drawings. Figure 2 The diagram shown is a flowchart illustrating a method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface according to an embodiment of this application. This embodiment provides a method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface, applied to a transmitting electronic device. The high-definition multimedia interface is a digital video interface that supports the RGB4:4:4 transmission protocol, such as... Figure 2 As shown, the method includes steps S201 to S204, as detailed below: S201. Acquire the video data to be transmitted, which carries RGB color signals and Alpha channel signals.

[0033] The YCbCr format video signal and Alpha channel signal to be transmitted can be generated by the GPU. The Alpha channel signal is a transparency control signal used to achieve image and text overlay. For example, in a live broadcast scene, the Alpha channel can be used to distinguish the overlay area between the anchor's image and the virtual background.

[0034] It should be noted that the high-definition multimedia interface can be either an HDMI interface or a DisplayPort (DP) interface, both of which support the RGB4:4:4 transmission protocol.

[0035] S202. Convert the RGB color signal into a YCbCr format video signal; the YCbCr format video signal includes: 8-bit luminance component Y, 4-bit chrominance component Cb, and 4-bit chrominance component Cr.

[0036] In some possible implementations, the RGB color signal is converted into a YCbCr format video signal, including: converting the RGB color signal into a YCbCr 4:2:2 format video signal.

[0037] In some possible implementations, the acquired YCbCr format video signal is a combination of 8-bit luminance component Y, 4-bit chrominance component Cb, and 4-bit chrominance component Cr, while the alpha channel signal is an 8-bit grayscale signal. This bit width configuration ensures both accurate color reproduction and precise control of transparency levels, while avoiding excessive bandwidth consumption due to excessive bit width.

[0038] S203. The YCbCr format video signal and the Alpha channel signal are mapped according to the pre-agreed mapping rules between the transmitting and receiving electronic devices, and combined with the signal bit width requirements of the RGB4:4:4 transmission protocol of the high-definition multimedia interface, and respectively filled into the RGB data to be transmitted according to the RGB4:4:4 transmission protocol. The total data volume per frame, the video resolution per frame, and the transmission timing specified by the interface protocol are consistent with the RGB4:4:4 format. This process can be referred to... Figure 4A and Figure 4B Signal mapping logic.

[0039] It should be noted that filling the RGB data to be sent according to the RGB4:4:4 transmission protocol means filling the dedicated carrying area of ​​the three color data channels of the RGB4:4:4 transmission protocol to generate data to be sent that conforms to the RGB4:4:4 transmission protocol.

[0040] In some possible implementations, the signal width of the RGB4:4:4 transmission protocol of the high-definition multimedia interface is 24 bits. The total bit width of the dedicated bearer interval is consistent with the 24-bit signal bit width. The total bit width of the YCbCr format video signal is 16 bits, which is carried by the full bit width interval of the R channel and the full bit width interval of the G channel. The 8-bit bit width of the Alpha channel signal is carried by the full bit width interval of the B channel alone. The bit width allocation of each component corresponds exactly to the component extraction interval preset by the receiver.

[0041] The pre-agreed mapping rules between the transmitter and receiver include: using an 8-bit channel bit sequence with bit 0 as the least significant bit and bit 7 as the most significant bit as a baseline, the 8-bit luminance component Y is filled into the full bit width range of bit 0 to bit 7 of the R channel; the 4-bit chrominance component Cr is filled into the high bit width range of bit 4 to bit 7 of the G channel; the 4-bit chrominance component Cb is filled into the low bit width range of bit 0 to bit 3 of the G channel; and the 8-bit alpha channel signal is filled into the full bit width range of bit 0 to bit 7 of the B channel. Furthermore, the filling ranges for each component do not overlap, and the filling operation is limited to its corresponding dedicated bearer range. This mapping rule enables interference-free independent transmission of each signal component, ensuring the accuracy of component extraction at the receiver.

[0042] The YCbCr format video signal and Alpha channel signal are mapped to the three color data channels of RGB4:4:4 format according to a preset bit width mapping rule. The 8-bit Y component is filled into the high 8 bits of the R channel, the 4-bit Cb component into the high 4 bits of the G channel, the 4-bit Cr component into the low 4 bits of the G channel, and the 8-bit Alpha channel signal into the high 8 bits of the B channel, forming 24-bit data conforming to the RGB4:4:4 protocol. This process can be found in [reference needed]. Figure 4A Signal mapping logic. Figure 4A The left side shows the video signal to be superimposed (A, taking a person's image as an example) and the corresponding Alpha channel signal (K, represented by a grayscale image of the person's outline, used to define the transparency area of ​​the image), while the middle shows the background signal (B, taking experimental equipment elements as an example). Through the calculation logic of the formula "C=A*K+B*(1-K)", the video signal, Alpha channel, and background signal are fused together, and finally the composite signal (C) on the right is obtained—the effect of the person's image and the experimental equipment background being naturally superimposed. This clearly demonstrates the core role of the Alpha channel in controlling the transparency of the image and achieving precise superposition in the context of image keying.

[0043] Figure 4BThis demonstrates the evolution of how video signal components and the alpha channel signal are carried, from "uncompressed" to "compressed" and then "fused." At the top is the uncompressed state, where the Y, Cb, and Cr components each occupy 4 units of resources, and the alpha channel occupies a separate container, resulting in fragmented resources and low utilization. The middle state is the compressed state, where the Y component remains at 4 units, and the Cb and Cr components are compressed to 2 units each, while the alpha channel still occupies a separate container. At the bottom is the compressed and fused state, maintaining the 4 units for the Y component and 2 units each for the Cb and Cr components, merging the Cb and Cr components into a single container (4 units in total), and integrating the alpha channel signal into the same container set. This achieves resource reuse between the video components and the alpha channel, visually demonstrating the optimization logic of signal carrying methods from fragmented to efficient fusion.

[0044] In some possible implementations, the YCbCr signal undergoes an integrity check before mapping to ensure no data loss. This check effectively prevents subsequent mapping errors due to signal damage, ensuring the accuracy of transmitted data.

[0045] Sending mapped RGB4:4:4 format data via a high-definition multimedia interface that supports the RGB4:4:4 transmission protocol can utilize an HDMI 2.0 interface as the transmission medium. This interface supports a transmission bandwidth of 18Gbps, which can meet the real-time transmission requirements of 4K resolution video including the alpha channel. The data transmission process can be found in [reference needed]. Figure 4C A schematic diagram of the transmission link.

[0046] Figure 4C This demonstrates the end-to-end transmission process of video signals with an alpha channel based on an HDMI interface. On the left transmitting end, the GPU first renders the original 24-bit RGB 4:4:4 graphics into a 16-bit YCbCr 4:2:2 video signal and an 8-bit alpha channel signal. Then, it integrates the two into 24-bit RGB 4:4:4 format data through a 4:4:4 mapping rule and sends it through the HDMI output interface. On the right receiving end, after receiving the data through the HDMI interface, it first restores it to the 24-bit RGB 4:4:4 format, then splits it into a 16-bit YCbCr 4:2:2 video signal and an 8-bit alpha channel signal, which are ultimately used for digital video processing and display. This fully demonstrates the entire "rendering-mapping-transmission-splitting" chain and reflects the technical logic of synchronously transmitting video and alpha channel signals through a single HDMI interface.

[0047] S204: Transmits the data to be transmitted to the receiving electronic device through a single high-definition multimedia interface to achieve synchronous transmission of the video signal and the Alpha channel signal carried in the data to be transmitted.

[0048] Depend on Figure 4C As can be seen, this step completes the single-cable transmission of video signals containing the Alpha channel. The transmitting end can complete the synchronous transmission of video and Alpha channel signals through a single HDMI cable without the need for additional physical interfaces, thus simplifying the transmission link.

[0049] This embodiment maps the YCbCr video signal and the Alpha channel signal to RGB4:4:4 format and achieves single-cable transmission using a standard HDMI interface, overcoming the drawbacks of traditional solutions that require dual interfaces or dedicated hardware. This solution reduces equipment costs and link complexity, and can be widely adapted to professional scenarios such as live streaming and virtual studios.

[0050] like Figure 3 This is a flowchart illustrating a method for receiving video signals containing an alpha channel based on a high-definition multimedia interface (HD Multimedia Interface). This method, applied to a receiving electronic device, uses an HD Multimedia Interface that supports the RGB4:4:4 transmission protocol. The method includes steps S301 to S304, as detailed below.

[0051] S301. Through a single high-definition multimedia interface, following the transmission timing specified by the RGB4:4:4 transmission protocol, the receiving and transmitting electronic devices are based on... Figure 2 The method shown is used to transmit the data to be sent.

[0052] In some possible implementations, the receiving end receives RGB4:4:4 format data transmitted via a high-definition multimedia interface, obtains 24-bit RGB4:4:4 format data transmitted by the sending end through an HDMI receiving module, and reads the synchronization check code in the data to confirm the integrity of the data frame.

[0053] S302. According to the pre-agreed mapping rules between the transmitting electronic device and the receiving electronic device, and in combination with the 24-bit signal width requirement of the RGB4:4:4 transmission protocol and the fact that each of the three color data channels R, G, and B under this protocol is allocated 8 bits of width, the YCbCr format video signal component and the Alpha channel signal component are extracted from the three color data channels of the data to be transmitted.

[0054] In some possible implementations, the mapping rules pre-agreed between the transmitting and receiving electronic devices include: using the 8-bit channel bit sequence with bit0 as the least significant bit and bit7 as the most significant bit as a reference, the full bit width range of bit0~bit7 of the R channel, the high bit width range of bit4~bit7 of the G channel, and the low bit width range of bit0~bit3 of the G channel are defined as the dedicated bearer range of the YCbCr format video signal, and the full bit width range of bit0~bit7 of the B channel is defined as the dedicated bearer range of the Alpha channel signal; and the dedicated bearer ranges of each component have no bit width overlap, and the extraction operation is only performed within the corresponding dedicated bearer range.

[0055] Extract the YCbCr component and Alpha channel signal from the RGB three-channel data. Following the reverse operation based on the sending end's mapping rules, extract the 8-bit Y component from the R channel, split the G channel into 4-bit Cb and 4-bit Cr components, and extract the 8-bit Alpha channel signal from the B channel. This extraction process can be found in [reference needed]. Figure 4C The parsing logic.

[0056] S303. Reassemble the extracted YCbCr format video signal components into a complete YCbCr format video signal and convert it into an RGB color signal; In some possible implementations, conversion to RGB color signals includes: converting to RGB color signals according to the YCbCr to RGB color space conversion formula specified in the Rec.709 high-definition video standard. The calculation results of the R, G, and B components in the conversion formula range from 0 to 255 to match the 8-bit storage width of the RGB three-channel, and the input and output bit widths of the formula are consistent with the specifications of the 8-bit luminance component Y and the 4-bit chrominance components Cb and Cr. The color conversion error conforms to the high-definition video color reproduction error threshold specified in the Rec.709 standard. The conversion formulas in the Rec.709 high-definition video standard include: R=Y+1.402 (Cr-128), G=Y-0.34414 (Cb-128)-0.71414 (Cr-128), B=Y+1.772 (Cb-128).

[0057] S304. Integrate the RGB color signal with the extracted Alpha channel signal component to generate target video data carrying the RGB color signal and Alpha channel signal. The total amount of data per frame and the resolution of the single frame of the target video data are consistent with the original video data to be transmitted by the transmitting electronic device.

[0058] In some possible implementations, in the RGB three color data channels of the data to be transmitted, the full bit width range of the R channel (bits 0-7), the high bit width range of the G channel (bits 4-7), and the low bit width range of the G channel (bits 0-3) are collectively defined as a 16-bit dedicated carrier range for YCbCr format video signals. The full bit width range of the B channel (bits 0-7) is separately defined as an 8-bit dedicated carrier range for the Alpha channel signal. Furthermore, the full bit width range of the R channel is dedicated to carrying the luminance component Y, and the high bit width range of the G channel (bits 4-7) is dedicated to carrying the color component Y. The chroma component Cr is carried by the low bit width range of the G channel (bits 0-3). The YCbCr format video signal component and the Alpha channel signal component are extracted separately, including: extracting the 8-bit luminance component Y from the full bit width range of the R channel, extracting the 4-bit chroma component Cr from the high bit width range of the G channel (bits 4-7), and extracting the 4-bit chroma component Cb from the low bit width range of the G channel (bits 0-3). These are then combined to form a 16-bit YCbCr format video signal component. The 8-bit Alpha channel signal component is extracted from the full bit width range of the B channel.

[0059] This embodiment achieves accurate parsing of video signals containing the alpha channel through reverse mapping, is compatible with the transmission protocol of the sending end, and requires no additional hardware adaptation. It ensures the integrity of the video image and the overlay effect, and is suitable for various professional video processing scenarios.

[0060] like Figure 5 As shown, one embodiment of this application provides an optoelectronic device 500, which serves as a transmitting electronic device to implement the method mentioned in the preceding method embodiments for transmitting video signals containing an alpha channel based on a high-definition multimedia interface. Its hardware components include: a high-definition multimedia interface supporting the RGB4:4:4 transmission protocol, such as an HDMI 2.1 interface, supporting an ultra-high bandwidth of 48Gbps, which can meet the transmission requirements of 8K resolution video with an alpha channel; a memory 501; and a processor 502. For example, the processor 502 may be equipped with an ARM Cortex-A78 architecture chip with a main frequency of 2.8GHz, capable of efficiently completing operations such as signal mapping, verification, and encapsulation; the memory 501 may be used to store mapping rules, signal data to be transmitted, and temporary processing files. When the processor 502 executes the computer-executable instructions in the memory 501, it can sequentially complete the entire process of signal acquisition, mapping, and transmission, realizing the function of transmitting video signals containing an alpha channel via a single cable.

[0061] like Figure 6As shown, one embodiment of this application also provides an electronic device 600 as a receiving end, used to implement the receiving method for parsing video signals containing an alpha channel based on a high-definition multimedia interface in the preceding method embodiments. The electronic device 600 includes: a high-definition multimedia interface supporting the RGB4:4:4 transmission protocol, such as an HDMI 2.1 receiving module, compatible with the signal transmission protocol of the transmitting end; a memory 601; and a processor 602. The memory 601 is used to cache the received RGB4:4:4 data and store parsing algorithm instructions. When the processor 602 executes the computer-executable instructions in the memory 601, the entire process of signal reception, parsing, conversion, and output can be completed, achieving accurate restoration of the video signal containing the alpha channel.

[0062] The above-described embodiments are optional embodiments provided by this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the technical scope disclosed in this application should be included within the protection scope of this application.

Claims

1. A method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface, characterized in that, Applied to transmitting electronic devices, the high-definition multimedia interface is a digital video interface that supports the RGB4:4:4 transmission protocol. The method includes the following steps: Acquire the video data to be transmitted, which carries RGB color signals and Alpha channel signals; The RGB color signal is converted into a YCbCr format video signal; the YCbCr format video signal includes: an 8-bit luminance component Y, a 4-bit chrominance component Cb, and a 4-bit chrominance component Cr. The YCbCr format video signal and the Alpha channel signal are filled into the RGB data to be sent according to the RGB4:4:4 transmission protocol corresponding to the high-definition multimedia interface, according to the mapping rules agreed upon in advance by the transmitting electronic device and the receiving electronic device, and in combination with the signal bit width requirements of the RGB4:4:4 transmission protocol of the high-definition multimedia interface. The total amount of data per frame, the resolution of video per frame and the transmission timing specified by the interface protocol of the data to be sent are consistent with the RGB4:4:4 format. The data to be transmitted is transmitted to the receiving electronic device through a single high-definition multimedia interface, thereby achieving synchronous transmission of the video signal and the Alpha channel signal carried in the data to be transmitted.

2. The method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface according to claim 1, characterized in that, The process of converting the RGB color signal into a YCbCr format video signal includes: The RGB color signal is converted into a YCbCr4:2:2 format video signal.

3. The method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface according to claim 1, characterized in that, The pre-agreed mapping rules between the sending end and the receiving end include: Based on the 8-bit channel bit sequence with bit 0 as the least significant bit and bit 7 as the most significant bit, the 8-bit luminance component Y is filled into the full bit width range of bit 0 to bit 7 of the R channel, the 4-bit chrominance component Cr is filled into the high bit width range of bit 4 to bit 7 of the G channel, the 4-bit chrominance component Cb is filled into the low bit width range of bit 0 to bit 3 of the G channel, and the 8-bit Alpha channel signal is filled into the full bit width range of bit 0 to bit 7 of the B channel; and the filling ranges of each component do not overlap, and the filling operation is only performed within the corresponding dedicated carrying range.

4. The method for transmitting video signals containing an alpha channel based on a high-definition multimedia interface according to claim 1, characterized in that, The signal width of the RGB4:4:4 transmission protocol of the high-definition multimedia interface is 24 bits. The total bit width of the dedicated bearer interval is consistent with the 24-bit signal width. The total bit width of the YCbCr format video signal is 16 bits, which is carried by the full bit width interval of the R channel and the full bit width interval of the G channel. The 8-bit bit width of the Alpha channel signal is carried by the full bit width interval of the B channel alone. The bit width allocation of each component corresponds exactly to the component extraction interval preset by the receiving end.

5. A method for receiving video signals containing an alpha channel based on a high-definition multimedia interface, characterized in that, Applied to receiving electronic devices, the high-definition multimedia interface is a digital video interface that supports the RGB4:4:4 transmission protocol. The method includes the following steps: Through a single high-definition multimedia interface, following the transmission timing specified by the RGB4:4:4 transmission protocol, the data to be transmitted by the sending electronic device based on the method of claim 1 is received. According to the pre-agreed mapping rules between the transmitting electronic device and the receiving electronic device, combined with the 24-bit signal width requirement of the RGB4:4:4 transmission protocol and the fact that each of the three color data channels R, G, and B under this protocol is allocated 8 bits of width, the YCbCr format video signal component and the Alpha channel signal component are extracted from the three color data channels of the data to be transmitted. The extracted YCbCr format video signal components are reassembled into a complete YCbCr format video signal and converted into RGB color signals; The RGB color signal is integrated with the extracted Alpha channel signal component to generate target video data carrying the RGB color signal and the Alpha channel signal. The total amount of data per frame and the resolution of the target video data are consistent with the original video data to be transmitted by the transmitting electronic device.

6. The method for receiving video signals containing an Alpha channel based on a high-definition multimedia interface according to claim 5, characterized in that, The conversion to RGB color signals includes: converting to RGB color signals according to the YCbCr to RGB color space conversion formula specified in the Rec.709 high-definition video standard. The calculation results of the R, G, and B components of the conversion formula have a value range of 0~255 to match the 8-bit storage width of the RGB three-channel, and the input and output bit width of the formula is consistent with the specifications of the 8-bit luminance component Y and the 4-bit chrominance components Cb and Cr. The color conversion error meets the high-definition video color reproduction error threshold specified in the Rec.709 standard.

7. The method for receiving video signals containing an Alpha channel based on a high-definition multimedia interface according to claim 5, characterized in that, The pre-agreed mapping rules between the transmitting electronic device and the receiving electronic device include: based on the 8-bit channel bit sequence with bit0 as the least significant bit and bit7 as the most significant bit, the full bit width range of bit0~bit7 of the R channel, the high bit width range of bit4~bit7 of the G channel, and the low bit width range of bit0~bit3 of the G channel are defined as the dedicated bearer range of the YCbCr format video signal, and the full bit width range of bit0~bit7 of the B channel is defined as the dedicated bearer range of the Alpha channel signal; and the dedicated bearer ranges of each component have no bit width overlap, and the extraction operation is only performed within the corresponding dedicated bearer range.

8. The method for receiving video signals containing an Alpha channel based on a high-definition multimedia interface according to any one of claims 5-7, characterized in that, In the RGB three color data channels of the data to be transmitted, the full bit width range of R channel (bits 0-7), the high bit width range of G channel (bits 4-7), and the low bit width range of G channel (bits 0-3) are collectively defined as a 16-bit YCbCr format video signal dedicated carrier range. The full bit width range of B channel (bits 0-7) is separately defined as an 8-bit Alpha channel signal dedicated carrier range. The full bit width range of R channel is dedicated to carrying the luminance component Y, the high bit width range of G channel (bits 4-7) is dedicated to carrying the chrominance component Cr, and the low bit width range of G channel (bits 0-3) is dedicated to carrying the chrominance component Cb. The extraction of YCbCr format video signal components and Alpha channel signal components includes: extracting 8-bit luminance component Y from the full bit width range of the R channel, extracting 4-bit chrominance component Cr from the high bit width range of bit 4 to bit 7 of the G channel, and extracting 4-bit chrominance component Cb from the low bit width range of bit 0 to bit 3 of the G channel, and merging them to form a 16-bit YCbCr format video signal component; and extracting 8-bit Alpha channel signal components from the full bit width range of the B channel.

9. An electronic device, characterized in that, As a transmitting electronic device, it includes: a high-definition multimedia interface supporting the RGB4:4:4 transmission protocol, a processor, and a memory, wherein the processor is configured to execute computer-executable instructions; the memory stores one or more computer-executable instructions, which, when executed by the processor, implement the various steps of the method for transmitting a video signal containing an alpha channel based on a high-definition multimedia interface as described in any one of claims 1-4.

10. An electronic device, characterized in that, As a receiving electronic device, it includes: a high-definition multimedia interface supporting the RGB4:4:4 transmission protocol, a processor, and a memory, wherein the processor is configured to execute computer-executable instructions; the memory stores one or more computer-executable instructions, which, when executed by the processor, implement the various steps of the receiving method for parsing a video signal containing an Alpha channel based on a high-definition multimedia interface as described in any one of claims 5-8.

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