Friends who often play high-definition video equipment know that HDMI is the most common interface for video signal transmission, but HDMI has several versions HDMI1.4, HDMI2.0, HDMI2.0a, etc., as a person who does not understand the technical details Users, it is really difficult to choose.
HDMI is an important way to link high-definition multimedia and TV. This is a digital video/audio interface technology that can transmit video signals and audio signals at the same time without digital-to-analog conversion, and it is very convenient to transmit video and audio Signal; video decoding output device, through HDMI can transmit video and audio to the delivery device with extremely high efficiency, it can work several commonly used multimedia devices such as smart TVs, set-top boxes, projectors, etc.
In a few words, I would like to introduce the history of this line; the first technology that appeared in the field of digital transmission was DVI instead of DHMI. With the development of digital high-definition audio-visual technology, there are more and more problems with the DVI interface, so it involves multiple Manufacturers in the field urgently need better high-definition video interface technology, which prompted the birth of the standard HDMI; it can be seen that this high-definition video link will also play an important role in the connection of multimedia devices in the future.
HDMI interfaces are divided into four types: A, B, C, and D.
Among them, Type A (Type A) is the most common. Generally flat-panel TVs or video devices provide interfaces of this size. Type A has 19 pins, a width of 13.9 mm, and a thickness of 4.45 mm. Devices that can be seen now 99% are HDMI interfaces of this size.
Type B (Type B) is very rare. It has 29 needles and a width of 21 mm. The transmission bandwidth is almost twice as large as that of Type A. It is completely too "powerful" for home applications, and it is only used in some professional occasions.
Type C (Type C) is created for small devices. Its size is 10.42×2.4 mm, which is nearly 1/3 smaller than Type A, and its application range is very small.
Type D (Type D) is the latest interface type. The size is further reduced. It adopts a double-row pin design. The size is similar to the miniUSB interface, which is more suitable for portable and in-vehicle devices.
Although the HDMI interfaces are different, the functions are the same. Usually, the quality of the HDMI interface is not less than 5000 times of plugging and unplugging. It can be used for 10 years when plugging and unplugging every day. It should be said that it is very durable. It is also worth mentioning that HDMI can be backward compatible with the DVI interface. Some older DVI devices can be connected through commercially available HDMI-DVI adapters, because DVI also uses the TMDS method. After the device is connected, DVI devices will be found. There is no CEC (consumer electronics control) function, nor can it accept audio signals, but it basically does not affect the transmission of video signals (gray adjustment may be required), so some monitors with only DVI interface can also be connected to HDMI devices.
In addition to the different types, the HDMI interface also corresponds to different functions.
The first: HDCP 2.2, this technology can protect high-value digital movies, TV shows and audio content from illegal theft and copying.
The second: HDMI-ARC (Audio Return Channel, sound return) function, used for the output of TV digital audio, you can connect an amplifier that also supports the ARC function, and transmit the sound of the TV to the amplifier.
The third one: bit refers to the color depth. The general notebook screen is 6bit, the high-end 8bit, and the special professional 10bit, which can be understood as the color depth of 2 to the 10th power, and 10bit specifically refers to a video coding technology that can provide Very high video quality, capable of showing extraordinary delicacy in the gradual and change of colors, but the requirements for the configuration to be able to play 10bit are still very high.
Fourth: MHL technology uses only five cables to transmit up to 4K ultra-high-definition uncompressed video with eight-channel digital audio, while also charging mobile devices.
1. Good quality: The digital interface has no loss of analog-to-digital conversion and can provide the best video quality. It is especially noticeable at high resolutions, such as 1080p or even 4K.
2. Easy to use: One line integrates video signals and multi-channel audio signals, which is much more practical than the situation where multiple lines were connected in the past.
3. Intelligentization: HDMI supports two-way communication between video sources and playback devices, realizing new functions, such as automatic configuration and one-key playback. By using HDMI, the device automatically transmits the most efficient format for the connected display device (for example, the TV supports up to 4k30P, HDMI will return the information, and the box will automatically set the resolution to 4k30P), so the user does not have to try to set it by himself Resolution.