Mobile wireless Ad Hoc networks (MANET) interconnect with Internet, satellite and the third generation mobile communication system by multi-hop, they forms the next generation Ad hoc network, which performs the merging and resources sharing in heterogeneous networks. The bandwidth and power are limited and there are all kinds of transmission errors in the environment of MANET, according to these characteristics of the next generation MANET, we propose a QoS control method for video transmission, based on directional-selective fractal interpolating. The simulated result shows that this new method has better performance than existing algorithms (such as bilinear interpolation), and can be adaptive to track the dynamic change of bandwidth.