Screen Projection – Introduction to WiDi Screen Projection Protocol, Advantages and Disadvantages
The current mainstream screen projection protocols are well-known to everyone, including Miracast, Airplay, DLNA, and WiDi. Among them, Miracast protocol mainly has the vast majority of user base, and Airplay screen mirroring is only used for IOS systems (Apple devices). DLNA is currently commonly used in video apps, and although we are not very familiar with WiDI protocol, we actually have many applications.
WiDi (Wireless Home Digital Interface) supports high-definition transmission within a distance of 7-15 meters, consisting of a sender and receiver. The sender is connected to playback devices such as computers, laptops, Blu ray players, high-definition players, PS3, etc. The receiver can be connected to display devices such as large LCD screens, high-definition televisions, high-definition projectors, home theaters, or simply speakers.
WiDi enables users to no longer be entangled by cables and easily establish wireless audio and video centers, which are widely used in conference rooms, lecture halls, lecture halls, cultural stages, home audio and video entertainment, KTV entertainment and other places. WiDi allows you to enjoy home entertainment with zero hassle, long-distance wireless transmission, automatic frequency switching, plug and play, and uncompressed 1080P wireless high-definition audio-visual feast!
The current system architecture of screen projectors on the market is mainly divided into Android and Linux architectures, and most Android boxes use Miracast screen projection technology.
The advantages of WHDi technology are as follows:
① Uncompressed video delivery
The most fundamental difference between WiDi technology and other wireless technologies is that it can transmit fully high-definition audio and video streams without compression. There are two main ways to transmit video wirelessly: one is to wirelessly transmit compressed audio and video streams at the transmitting end, and the other is to decompress and restore images at the receiving end, represented by WiFi and UWB technologies. Another method is to directly transmit the video frequency stream output by the video source to the receiver through wireless means, and output images, represented by WiDi. Only WiDI technology can achieve this in the industry.
② Transmission without delay
Due to the sufficient wireless bandwidth provided by WiDi technology, there is no need to transmit through compression, saving the time required for video compression and decompression, thus ensuring that the transmitted video has no delay at all.
③ Resolution up to 1080P
WHDI technology supports video resolution up to 1920X1080P. Subsequent software upgrades can support resolutions up to 2KX4K. Equivalent to 4 times 1080P.
④ Supports 7.1 channels
In addition to being able to transmit high-definition videos, WiDI technology can support 7.1 channel (PCM) audio transmission with a sampling rate of up to 24 bits and 192KHz.
⑤ 100K backhaul channel
In addition to being able to transmit audio and video, WiDI technology also provides a 100K backhaul channel. The purpose of setting the backhaul channel is to enable mutual verification of the control protocol of HDCP between the transmitting and receiving ends. At present, domestic WiDI module manufacturer Shimeng Company has achieved USB keyboard and mouse backhaul function through this channel, namely UWTC (USB Wireless Transmission Control) technology, and has mastered remote control technology for multi touch.
⑥ Supports HDCP2.0 technology
The HDCP organization has separately set the technical standards for HDCP2.0 for WHDI technology. HDCP2.0 allows users to achieve one to many and many to many HDCP interactive authentication through WHDI technology. HDCP2.0 technology allows a video source with a content protection protocol to be displayed simultaneously on multiple display terminals. This is completely impossible to achieve in the HDMI 1.2 standard.
⑦ The Disadvantages of WiDI Technology
The disadvantage is that it lacks universality. Due to our phones and computers not supporting the WHDI protocol, WiDI protocol cannot have a wide user base like Miracast screen casting technology. However, with the gradual maturity of wireless screen projectors and software, WiDI technology has also achieved good compatibility, and it is likely that it will be familiar to everyone in the future.