WebLearning-plus is a multicast-based collaborative learning environment we developed, in which scalable video coding and adaptive multicast transmission are the key issues. According to the demand of adaptive video multicast in WebLearning-plus for the coder, we present a new scalable wavelet based video coding approach named ViCowel, which is a kind of set partition based on line scanning. Experiments show that it has better flexibility in video multicast applications.