Development of mobile audio and video communication

At present, a variety of instant messaging software is used on the mobile phone, service providers also provide more and more rich communication service functions. With the development of the Internet, the use of instant messaging will become increasingly widespread, the instant messaging software industry is booming. Now the market competition is more and more fierce, how to complete the project in a limited time to put the main energy into the business logic of the project, speed up the project development progress, become the development of the work of the top priority. This paper introduces a simple instant messaging system based on Android platform, and studies the structure of communication system between various mobile clients and servers on the open source server OpenFire, and realizes the client function.
The Android platform framework consists of 5 parts. The underlying core is based on LINUX2. The 6 kernel develops a standalone operating system that is used to provide the underlying services of the system, including security mechanisms, memory management, process management, network stacks, and a range of driver modules. The middle is the Android execution environment, which includes the system runtime, the Dalvik virtual machine, the core library, and some C + + libraries that support the various components of Android. Application-layer frameworks are developers who use these API frameworks to develop their own applications, simplifying the architectural design of application development. Application-level programs are programs written in the Java language that run on virtual machines.

    on AndroidPlatform development of instant mobile phone communication system, it can enable users to log on the mobile phone client server, convenient, quick to send and receive instant messages. With the further research, the system can realize the transmission and reception of pictures, as well as some other functions, which can make the system function more diversified. The communication system architecture uses the C/S mode, which is the client/server architecture.
The client is responsible for initializing the communication process, and the client is responsible for initiating the connection request to the server when making instant communication. The server side uses open source OpenFire as the server, allowing multiple clients to log in simultaneously and connect to a server at the same time. The server authenticates each client and creates a session for the client through which authentication is made, enabling communication between the client and client.

The client of the system locates on the Android platform handset, uses the simple protocol as the Instant Communication protocol, simple (SIP for Instant Messaging and Presence leveragingextensions) is SIP (Session initiation Protocol), which developed a comprehensive set of schema and extension specifications for the SIP protocol to support IM. Simple to pass state information and implement distribution information representation through SIP. The XML parsing package provided by the Android platform is used to parse the XML according to protocol rules. According to the characteristics of the activity module running on the main thread, multithreading technology is used to solve the system communication problem. The user information and chat information of the system are stored in the SQLite database of the Android platform itself.

The system server uses open source OpenFire to establish an instant Communications Server. OpenFire is developed in the Java language, and the Java language has a cross-platform feature, so the OpenFire server can be built on a variety of operating system platforms. The kernel of the OpenFire server consists mainly of the server connection management component, the session management component, the data storage component and the transmitter component. OpenFire implementation of the plug-in mechanism, easy to expand, through the installation and the Heterogeneous network communication plug-in, you can communicate with other communications software.

Using Apache's Mina framework for network connectivity in network connectivity, the Mina framework uses non-blocking, high-performance I/O low-level, asynchronous I/O events and event-driven mechanisms that enable the server to be highly efficient and performance-capable of handling a large number of client connection events and I/O random events in a timely manner. A single server can support tens of thousands of concurrent users. The system client terminal connects to the server through the 3G wireless network using TCP protocol, and communicates in time through simple instant communication protocol. In the mobile network, mobile terminal access to 3G, 4G wireless network. Gateway Mobile Switching Center gmsc (Gatewaymobile switc-hing Centre) provides users with the ability to group routes, tunnels, and track the location of mobile terminals. UMTS (Universal Mobile telecommunicationssystem) provides routing and encapsulation of network internal and external networks, assigns IP addresses, and enables interoperability with Internet networks.

The server authenticates the user name and password entered by the user, and after successful verification, the client reads the client's personal information from the server side and updates the Friend list and group information, the server responds to the client's requests, the client can send the receiving information, and the communication is completed to exit the system login status. In this way, a simple instant messaging system is implemented.
Mobile Hardware Platform
Minimum hardware configuration
Cpu:ti OMAP 850,200mhz
rom:32m
ram:32m
Recommended hardware configuration
Cpu:qualcomm MSM 7201a,528mhz
rom:128m
ram:128m

Development of mobile audio and video communication