ABSTRACT
Communication has always been a basic demand for human beings, and the development of Internet oers us more and more choices. Having experienced the evolution from message chatting to VoIP, now we are in the age of video chatting or video conferencing. Video conferencing is not a new issue, and there have been many mature products based on H.323 protocol in use. But before its birth, problems of cost and scalability haven’t been solved properly for decades. The central component MCU needs to decode each stream, mix them and then encode them, which requires more computation and more participants, so MCU needs to be powerful, and usually appears as expensive customized hardware. These expensive video conferencing solutions apparently can’t satisfy our demands for communication, and in fact, mostly for business use. To meet the demands of end consumers, software-based video conferencing products utilizing new architecture have appeared in recent years, which oer services for free or at low costs. Undoubtedly, Skype and Google Hangouts are among the most popular ones on the Internet. Unlike Skype, which has been the leader of Internet communication tools since the age of VoIP, Google Hangouts is quite a young product. It oers free 720p HD video conferencing for at most 10 people, which is quite outstanding in this field, and with the support of SVC technology and powerful Google network, it can oer high quality video conferencing service to users all over the world, which is quite hard for other products. All these features make it be a strong competitor in this field and a good object for researchers to study.
