In recent years, IEEE 802.11 wireless local area networks (WLANs) have been widely deployed. However, robust streaming of video over 802.11 WLANs still faces many challenges, such as bandwidth variation, diversified receivers, transportation over heterogeneous network, etc. Scalable Video Coding (SVC), an extension of the Advanced Video Coding (H.264/AVC), has been designed for heterogeneous network. This paper focuses on SVC video packet transmission from Ethernet to 802.11 and proposes an application layer adaptive video packets encapsulation method, which appends the truncated enhancement layer slice of SVC into the idle space of the 802.11 frame. The proposed method can efficiently utilize the bandwidth of 802.11 and promote the received video quality. The simulation results show that the proposed method can get an average gain about 0.7dB compared with conventional algorithms.