Video transmission over wireless ad hoc networks is hampered by packet losses. Even a single packet loss may cause error propagation until an intra-coded frame is received. Indeed, packet losses greatly degrade the video quality. In this paper, we propose an Unbalanced Multiple Description Coding (UMDC) scheme over a single path which requires only one single path as additional links are difficult to be guaranteed in reality and is capable of quickly recovering from packet losses and ensuring continuous playback. The proposed scheme uses two descriptions, the High-Resolution (HR) description and the Low-Resolution (LR) one. It uses the `peg frames' to limit error propagation in the HR description. The two descriptions can help each other recover from packet losses. The simulation results show that the proposed UMDC scheme over a single path has a comparable performance with our UMDC scheme with multiple path transmission (MPT) and has a better viewing experience than the state-of-the-art FEC-based scheme.