wireless screen projection refers to a way that the intelligent mobile device client displays the screen image and sound of the machine on another display device through WiFi, so as to realize the same screen display. With the rapid development of business projection technology, there are more and more electronic products supporting projection. What are the implementation technologies of wireless projection?
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today will take you to the system to learn about the five wireless projection technologies.
figure 1 # technical diagram of five screens 1 Airplay screen image
airplay is a wireless technology unique to Apple devices. Through WiFi connection, we can project graphic and video information on IOS devices such as iPhone and iPad to devices supporting airplay through wireless transmission. Because Apple devices do not allow third-party programs to obtain their screen images, many domestic wireless projection boxes are realized by cracking the airplay protocol. The operation mode of
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screen projection is very simple. If you are an apple mobile phone, slide your finger upward at the bottom of the mobile phone screen, call out the detailed panel of the control center, click “screen image” → select device → screen projection. Apple’s iPad is also projected through “screen image”, but the location of the control center is at the bottom of the screen and in the upper right corner of the screen.
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it is worth reminding that the screen projection through the airplay screen image needs to ensure that the Apple device and the screen projector are under the same LAN (the same network segment) and cannot be used across network segments and VLANs. It is troublesome for enterprises with network architecture to use them.
Figure 2. Image of airplay screen 2 Miracast multi screen interactive
miracast is the certified name of Wi Fi Alliance for devices supporting Wi Fi display function. Miracast screen projection technology is mainly used on two devices:
(1) some Android phones that support multi screen interaction
android5 Mobile phones above 0 usually come with miracast screen projection protocol. Wireless display can be realized through the internal settings of the mobile phone without installing any software or any network support.
figure 3. Schematic diagram of wireless display of Xiaomi mobile phone
(2) Windows 8 / 10 computer
the widi protocol natively supported by Windows 8 / 10 computer is improved based on the miracast protocol, and the screen can be cast directly without installing any software.
which displays support wireless projection?
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Figure 4 # windows 10 projection function
, but miracast has two disadvantages, which limits its use in high demand occasions. First, the bottom layer is UDP transmission protocol. The transmission process is unreliable and vulnerable to interference, which will lead to flower screen at the receiving end; Second, each Android device manufacturer has designed different ways to open miracast, which leads to the failure of unified training and large-scale promotion.
3. DLNA pushes
. The full name of DLNA is digital living network alliance, which aims to solve the interconnection between mobile devices and consumer appliances. DLNA projection is usually used in combination with miracast. Since miracast is a mirror projection, it will damage the image. DLNA projection adopts the so-called push mode, which essentially pushes the content on the mobile phone to the large screen (TV or projector) in the form of URL for playback. This method ensures the image quality without damage and has certain requirements for the network, but there is no picture at the transmitting end. It is mostly used in home cinemas and is not suitable for enterprises.
figure 5. DLNA push 4 Private screen projection Protocol
generally, screen projection equipment manufacturers will have their own customized private screen projection protocol. Take the flying picture projection protocol of Tu Feifei brand for example, it can be divided into two forms:
(1) “screen projection expert” software
users can directly download the “screen projection expert” software corresponding to the flying picture box at the transmitting end (computer or mobile phone), The screen content of the transmitting end is mirrored and projected onto the large display screen (Conference tablet or projection device) through software. The custom software protocol includes Mac OS computer software projection and windows computer software projection. The “screen projection expert” software developed by tufeifei brand is green software, which does not need to be installed, and the transmission quality is almost the same as that of the hardware transmitter. However, as a private agreement independently developed by tufeifei brand, it can not be used with other furniture.
(2) hardware Papa transmitter projection
the display information of the user computer (notebook or desktop computer) can be wirelessly transmitted to the receiving end (flying picture box) through the papa transmitter of the paired flying picture box, and then transmitted to the large screen display device through the wired connection of the receiving end, so as to realize the projection function.
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are not difficult to see that the flying picture projection protocol does not specifically refer to a specific projection mode, but refers to the integration of multiple projection modes.
Figure 6 schematic diagram of airmap protocol screen projection 5 HDM transmitter wireless projection mode
HDMI transmitter wireless projection mode, that is, the HDMI transmitter directly obtains the projection information from the HDMI output interface of the transmitting end, compresses and encodes it and sends it to the receiving end. There are mainly two protocols that adopt this screen projection mode: one is the equipment using whdi protocol; Second, devices using wirelesshd protocol. Its disadvantages are also obvious. Many transmitter devices have no HDMI output port, so it is impossible to cast the screen in this way.
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after reading this article, you should be able to understand that there are five kinds of wireless screen projection technologies to realize the same screen interaction, including miracast, airplay, DLNA, enterprise private screen projection protocol and HDMI direct plug-in screen projection technology. What kind of method are you using now?