Video adaptive streaming in mobile devices has always been a hard problem, and MPEG-DASH is considered to be a solution. DASH protocol requires the server to offer profiles of multiple bitrates at the same time. We can get a smoother playback as the profile number grows. However, we notice that the increase of profiles will bring in excessively frequent switches which will in turn cause a drop in QoE. Besides, growing numbers of media segments will put large burden on the backbone network. In this paper we use a proxy-assistant architecture to address above two problems. At the client side, we propose a new rate adaption method to ensure a smooth playback at the expense of a little average overall bandwidth. On the proxy server side, the smart proxy tries to aggregate similar requests with a map of importance of profiles for different bitrates. Compared with prior proxy based scheme, our scheme is proved to aggregate alike requests to reduce the cache hit ratio. The result shows that our method reduces the switching times and server requests times with the bitrate selecting by the proxy a little lower than the actual optimal one, and consequently makes our scheme both QoEfriendly and efficient under low-delay and multiple profiles scenario.