With the upgrade of network bandwidth and expanding of customer scale, IPTV is growing fast as a new broadband application. The distinctive feature of IPTV is its interaction and real-time property. Owing to this technology, people change their "watching" TV tradition by freely choosing or ordering the TV programs. Besides this application, the business operators are trying to explore other value-added services of IPTV.  

As a new business, video chat service has wide application prospect. However, this service has a close relationship with the embedded devices. The sending rate of embedded devices is constrained and it will inevitably lead to a great end-to-end delay. So in order to solve this technical problem, CHEN Junjie, NI Hong and SUN Peng of Institute of Acoustics, Chinese Academy of Sciences carried out a series of studies and put forward a new method to optimize the embedded device property in video chat.　  

They adopt frame-dropping algorithm and program the system actively drop the sending data according to the delay constraint and maximum transmission rate. By dropping some B frames, the peak rate of VBR video traffic is weaken. The researchers conduct practical experiment and simulation results show that frame-dropping algorithm can guarantee acceptable end-to-end delay and avoid buffer underflow.