Design And Implementation Of Digital Video Intercom System Based On Android

With the development of technology and improvement of living standard, using visitor registration and janitor on duty as the backward management methods of residential property management is hard to meet people’s need of community safety and property management convenience. But this problem can be settled by building intercom system through visitor management. Digital Video Intercom System emerged with the rapid development of audio and video codec technology and Internet technology. The core of the system is the terminal on which the functions such as video intercom system, access control and zone alarm are finished. And the terminal is consisted of the outdoor unit at the entrance of the building and the indoor unit. Therefore, it’s important for Digital Video Intercom System to develop a terminal with low cost and short development cycle.This thesis introduces an implementation scheme of the terminal of Digital Video Intercom System based on Android platform. The hardware of the scheme is i.MX27 from Freescale and the software is based on Android platform. Audio G.711 A codec and video H.264 codec can make the building intercom terminal digital. The terminal software is consisted of application management module, the operating system, SIP signaling module, video intercom system, bottom-drivers and bootstrap. The application management module is mainly used to realize the interaction between terminal and user and information management. The application is named Videophone and it can load automatically and resident in memory after Android started while other APK program has to be called by internal references of Videophone. The bottom-drivers can connect the operating system to the underlying hardware. SIP signaling module is mainly used for specific signaling management and routing. It provides terminal with SIP interaction ability which has many functions like the negotiation, establishment and destruction of VOIP calls. It also provides video intercom system with necessary establishment parameters and provides application layer with API function. Audio and video data collection and transmission are two functions of video intercom system which is used for the collection and playback of audio and video. Video intercom system also has other functions like encapsulation and decomposition of audio and video media packets, sending and receiving packets, etc. Bootloader is in charge of hardware initialization, booting the system start-up and burning image file.In this thesis, the principle and transplantation method of Bootloader and Android drivers of the terminal equipment as well as the principle and implementation method of videophone module are introduced. Besides, functional requirements of each module and terminal equipment were tested. Fortunately, the ultimate digital intercom terminal performed well and can meet the design requirements.