HDMI 2.1 will connect the ultra-high-definition 8K world
HDMI can be regarded as the most commonly encountered interface in our daily life, especially when using PCs, TVs and other equipment, it is almost indispensable to use it. Since its inception, HDMI has established the concept of "integrated audio and video" transmission. Being able to transmit audio and video data at the same time makes it stand out from a number of interface standards. After years of development, the version of the HDMI interface has evolved from HDMI 1.0 to HDMI 2.0. At the end of last year, the HDMI organization HDMI Forum Inc officially released the latest HDMI 2.1.
Since analog signals such as VGA exit the stage of history, interfaces such as DVI, HDMI, or DisplayPort have relied on digital signals to complete the data transmission of audiovisual graphics. Digital signals are much stronger than analog signals in terms of anti-interference ability, transmission security, and data reliability. However, the problem with digital signal transmission is that the higher the resolution, the richer the audio information, and the greater the bandwidth requirements.
For example, 1080p video bandwidth requires approximately 3Gbps without compression. Considering audio signals and other information, the HDMI 1.0 specification that supports both audio and video transmission sets the maximum bandwidth at 4.95Gbps. In the subsequent update, considering the support for 4K resolution, the HDMI 1.4 specification increased the transmission bandwidth to 10.2Gbps, but this bandwidth can only barely complete the transmission of 4K & 30Hz video signals. If higher 4K & 60Hz is needed, it will be stretched.
HDMI 2.0 changed this situation, and the bandwidth further soared to 18Gbps. It can already support 4K & 60Hz, which basically covers all the current requirements for loans for mainstream video resolutions. It also adds support for multi-channel lossless audio. The performance is satisfactory.
However, the HDMI 2.0 specification currently lacks forward-looking. Because the industry has introduced standards such as 4K & 120Hz, 8K & 60Hz, and even 10K in the direction of future audiovisual video development. The resolution of 8K is as high as 7680 × 4360, and the resolution of 10K is 10240 × 4320. The higher resolution brings clearer picture quality, and it is accompanied by a huge increase in data bandwidth requirements. Need to support transmission specifications, HDMI 2.0 obviously can not meet the needs.
In the latest HDMI 2.1 specification, the maximum bandwidth increase is calculated by "times", from the previous 18Gbps to 48Gbps, which is up to 2 times. The 48Gbps bandwidth can fully meet the future 8K and 10K ultra-high-definition resolution requirements, and it can also reserve bandwidth for simultaneous transmission of multiple lossless audio channels.
After the bandwidth increase, can the old HDMI data cables and interfaces still be used? The answer is obviously no. Due to the surge in bandwidth, the new HDMI 2.1 adds new requirements on cable design and interface design to meet the stability and integrity of data signals under high-speed transmission. Therefore, HDMI 2.1 interfaces and cables need to pass HDMI 2.1 certification The previous HDMI 1.4 and HDMI 2.0 specifications of interfaces and cables used in devices that support HDMI 2.1 cannot obtain new specifications, but on the contrary, HDMI 2.1 cables are backward compatible with all previous specifications.
In addition to the most fundamental and core change in bandwidth explosion, the HDMI 2.1 specification has undergone many changes in other technologies. Including dynamic HDR, static HDR, variable refresh rate, fast media switching, fast town transmission, automatic low-latency mode, etc. In fact, since HDMI 2.0, the HDMI organization has begun to add a large number of new technologies to the new specification, so that the video output effect is better and more in line with the needs of people in the future. The following article briefly introduces the new technologies added in the HDMI 2.1 specification.
HDMI 2.1 has added support for HDR technology. With displays that support HDR technology, users can see pictures with higher contrast and more pleasing colors.
ARC means that HDMI can allow audio signals to be transmitted back through the HDMI data cable, which can save the cables and interfaces required for repeated transmission of audio data. On HDMI 2.1, it supports eARC enhanced audio return channel function. This technology realizes low-jitter, high-bandwidth, high-fidelity audio return through the use of two additional channels. It supports up to 8 channels of 24-bit, uncompressed 192kHz audio. It can also return the popular Dolby Atmos and DTS: X and other audio signals to improve the efficiency and quality of audio backhaul.
Considering the current video formats with different frame rates, especially the changes in the frame rate for games, new requirements are placed on the display, HDMI 2.1 provides support for VRR technology, which is a variable refresh rate. VRR technology has certain similarities with G-Sync and Free-Sync on the desktop. Both use a display screen with a variable refresh rate to eliminate video frame delays, tearing, and stuttering.
Fast media switching is a new technology. This technology mainly eliminates problems such as black screen delays when switching media or input sources in current display devices through faster matching of signals and display devices. The fast frame transfer function is also a new technology designed to reduce frame delay, improve the smoothness of games and videos, and reduce tearing. Automatic low-latency technology is used to automatically correct and match low-latency devices, reducing picture transmission delays and improving fluency.
Since analog signals such as VGA exit the stage of history, interfaces such as DVI, HDMI, or DisplayPort have relied on digital signals to complete the data transmission of audiovisual graphics. Digital signals are much stronger than analog signals in terms of anti-interference ability, transmission security, and data reliability. However, the problem with digital signal transmission is that the higher the resolution, the richer the audio information, and the greater the bandwidth requirements.
HDMI 2.0 changed this situation, and the bandwidth further soared to 18Gbps. It can already support 4K & 60Hz, which basically covers all the current requirements for loans for mainstream video resolutions. It also adds support for multi-channel lossless audio. The performance is satisfactory.
However, the HDMI 2.0 specification currently lacks forward-looking. Because the industry has introduced standards such as 4K & 120Hz, 8K & 60Hz, and even 10K in the direction of future audiovisual video development. The resolution of 8K is as high as 7680 × 4360, and the resolution of 10K is 10240 × 4320. The higher resolution brings clearer picture quality, and it is accompanied by a huge increase in data bandwidth requirements. Need to support transmission specifications, HDMI 2.0 obviously can not meet the needs.
After the bandwidth increase, can the old HDMI data cables and interfaces still be used? The answer is obviously no. Due to the surge in bandwidth, the new HDMI 2.1 adds new requirements on cable design and interface design to meet the stability and integrity of data signals under high-speed transmission. Therefore, HDMI 2.1 interfaces and cables need to pass HDMI 2.1 certification The previous HDMI 1.4 and HDMI 2.0 specifications of interfaces and cables used in devices that support HDMI 2.1 cannot obtain new specifications, but on the contrary, HDMI 2.1 cables are backward compatible with all previous specifications.
In addition to the most fundamental and core change in bandwidth explosion, the HDMI 2.1 specification has undergone many changes in other technologies. Including dynamic HDR, static HDR, variable refresh rate, fast media switching, fast town transmission, automatic low-latency mode, etc. In fact, since HDMI 2.0, the HDMI organization has begun to add a large number of new technologies to the new specification, so that the video output effect is better and more in line with the needs of people in the future. The following article briefly introduces the new technologies added in the HDMI 2.1 specification.
HDMI 2.1 has added support for HDR technology. With displays that support HDR technology, users can see pictures with higher contrast and more pleasing colors.
ARC means that HDMI can allow audio signals to be transmitted back through the HDMI data cable, which can save the cables and interfaces required for repeated transmission of audio data. On HDMI 2.1, it supports eARC enhanced audio return channel function. This technology realizes low-jitter, high-bandwidth, high-fidelity audio return through the use of two additional channels. It supports up to 8 channels of 24-bit, uncompressed 192kHz audio. It can also return the popular Dolby Atmos and DTS: X and other audio signals to improve the efficiency and quality of audio backhaul.
Considering the current video formats with different frame rates, especially the changes in the frame rate for games, new requirements are placed on the display, HDMI 2.1 provides support for VRR technology, which is a variable refresh rate. VRR technology has certain similarities with G-Sync and Free-Sync on the desktop. Both use a display screen with a variable refresh rate to eliminate video frame delays, tearing, and stuttering.
Fast media switching is a new technology. This technology mainly eliminates problems such as black screen delays when switching media or input sources in current display devices through faster matching of signals and display devices. The fast frame transfer function is also a new technology designed to reduce frame delay, improve the smoothness of games and videos, and reduce tearing. Automatic low-latency technology is used to automatically correct and match low-latency devices, reducing picture transmission delays and improving fluency.
HDMI 2.1 began to support display stream compression, which is the DSC function. The main purpose of this function is to achieve lossless compression of video, so that data transmission takes up less bandwidth, lower power, and reduces electromagnetic interference.
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