Video calling, also known as video calling, is divided into two ways of taking an IP line and taking an ordinary phone line. Video call usually refers to a communication method based on the Internet or mobile Internet (3G / 4G Internet) end, which transmits human voice and images (user's bust, photos, items, etc.) in real time through terminal devices. Video call requires two network-connected terminal devices, through integrated software or third-party software to achieve real-time two-way audio and video transmission. With the rapid improvement of network bandwidth and the development and popularization of hardware equipment, the video call market has also entered the fast lane of development.
The current society is changing rapidly, and all kinds of unexpected situations exist every moment. The current emergency command is built to solve the remote and modern command and dispatch needs of coordinated communication and response to emergencies, individual events, group events, and social events. It has the following characteristics:
1. Flexible and flexible, easy to deploy and recycle.
2. Audio and video can be recorded in real-time communication, and the location of each unit is displayed in real time.
3. Can be used around the clock, with strong environmental suitability, stable and reliable communication.
The block diagram of common scenes of emergency system is as follows:
As shown in the above figure, the previous emergency system is commonly used in mobile command agents, dispatching phones, factory broadcasting, cluster intercom, office phones, smart handheld terminals, 2G mobile phones and so on. The above are often limited to regions. Although there are multi-level dispatching and commanding capabilities, the venues are relatively estimated, and it is impossible to truly achieve portable, mobile, and intelligent emergency treatment.
The portable mobile communication terminal developed by Chenhan Electronics came into being. This equipment originated from satellite communication products independently developed for military industrial enterprises. This product is designed and developed according to military grade, with waterproof, dustproof, anti-drop function, based on Android 4.4 system development, mainly provides satellite phone, image acquisition and transmission, two-way video call, file transmission, remote network access, data transmission and other functions . The product can be applied to various satellite ground stations according to actual needs, such as command center main station, vehicle-mounted station, portable mobile communication station, etc. When it is used as a portable mobile communication station, it needs an external portable satellite antenna and a portable generator.
In order to realize this complete set of portable terminals, Chenhan Electronics designed the entire system block diagram:
The overall system block diagram is as follows:
Its main hardware configuration is equipped with Freescale I.MX6Q CPU, clocked at 1G, DDR3 memory 1GB, built-in EMMC4GB, 12V power supply, equipped with 7-inch LCD display, the entire portable device has switch control and restart function, battery capacity can 10.8V / 3Ah, continuous working time is not less than 2.5 hours. At the same time, the whole machine is equipped with various buttons, audio and video interfaces, I2C interfaces, various sensors, etc., which can realize various required functions.
The portable terminal is also combined with embedded application system software. By connecting the two-way transceiver station, it realizes the functions of audio and video intercom at low bit rate, high-definition data transmission, Beidou positioning message transmission and other functions. The modular system can be optionally configured as GPS / Beidou dual-mode system. In the design, the special use requirements of the broadcast receiving equipment are also fully considered. The satellite application handheld terminal has excellent service quality and good network interconnectivity. The modular design makes the network performance stable, easy to expand, efficient, economical, reliable.
The software operation flow chart is as follows:
The main features of the software are as follows: powerful video acquisition and processing functions, support for video recording, video encoding compression, UDP access operation functions, video compression rate and format can be set, video communication playback and storage functions between two terminals can be completed, video Resolution: 800 & TImes; 480, video frame rate: 25 / 30fps, video encoding compression: can support 64/128/256/384 / 512kbps, encoding format: H.264 / mp4 / WMV; powerful video playback function: support Local or UDP access video playback function, can complete the WMV hard decoding video playback function, the maximum support for receiving information transmission rate is 30Mbit / s; file transmission function: support files and pictures through UDP access operation function, can complete the two terminals File and picture transmission and storage functions; Narrowband video call function: the bit rate can be as low as 10kbps, you can choose 10kbps, 32kbps, 64kbps, 100kbps, etc. to 512kbps; HD map viewing / navigation function: can realize the distribution of high-definition maps and navigation, view the current location information.
In summary, the portable terminal provides users with a multi-task satellite communication platform. Through the combination of hardware platform and software platform, users can easily establish satellite communication with the command center or other terminals no matter where they are. Links, transmitting images, voice, data and other services. Products can be widely used in agriculture, forestry, fishery, medical and health, metallurgy and minerals, water conservancy and hydropower, transportation, mechanical and electrical machinery and other industries with strict environmental requirements such as civil, industrial and military.
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FOSHAN SHUNDE LANGLI HARDWARE ELECTRICAL CO.LTD , https://www.langliplastic.com