A Kind Of Design And Implement Of Embedded Video IP Phone Terminal

Modern communication technology enables people have a higher requirement for the the communication services,so Video Phone come into being.Video phone based on the early public telephone switching network has gradually withdrawn from the history,because the transfer rate can not meet the requirements of high-performance video communication.With the the emergence and improvement of the audio and video codec standards,real-time transport protocol and signaling protocols as well as the continuous development of IP technology,IP-based Video Phone has gained a unified technical standards,and gradually developed into a direction in the Video Phone market.This paper provides an overview of Video IP Phone's history and development, points out that these products possess the hardware design complexity,lower resolution images,more network bandwidth and higher price,etc,analyzes the significance of design and implement of a higher performance and cheaper Video IP Phone Teminal,puts forward the design scheme based on Freescale's i.mx27,researches its implement of the hardware and softeware,at last,initially realizes it in LAN.Single-chip design without external audio and video codec DSP processors improves the system integration and stability,reduces power consumption and hardware costs;In software design,using of the hierarchical design method of"top-down,and gradually refining"to dividing the software into application-layer,middleware,and the bottom level,so the software will have a strong transplantation and scalability,can be used in the same product's development and Video IP Phone's secondary development;In software implement,with porting the Linux kernel to the bottom level,using the Semaphore mechanism to effectively solve multi-channel video codec.meets the telephone terminal's requirement of video encoding and decoding at the same time.by drawing Linux's Multi-threaded mechanism to the software implement to build a platform for the operation of multitask related to voice and vedio in the Video IP Phone Terminal.