Broadcast delivery of bulk multimedia files is an important wireless LAN application for densely populated scenarios such as inside high-speed train carriages. However, it is a challenge to adapt the broadcast link rate due to heterogeneity and varying channel conditions of the broadcast receivers to achieve both high bandwidth efficiency and fairness. In this paper, the broadcast link rate adaption problem is formulated as a quadratic programming problem with a broadcast link rate adaption algorithm named FBB (Fair and Bandwidth-efficient Broadcast). Simulation results show that the algorithm significantly outperforms fixed rate broadcast with only a small loss compared to its theoretical performance. The algorithm has been successfully applied in a practical wireless LAN access point. Broadcast delivery of bulk multimedia files is an important wireless LAN application for densely populated scenarios such as inside high-speed train carriages. However, it is a challenge to adapt the broadcast link rate due to heterogeneity and varying channel conditions of the broadcast receivers to achieve both high bandwidth efficiency and fairness. In this paper, the broadcast link rate adapter problem is formulated as a quadratic programming problem with a broadcast link rate adaption algorithm named FBB (Fair and Bandwidth-efficient Broadcast). Simulation results show that the algorithm significantly outperforms fixed rate broadcast with only a small loss compared to its theoretical performance. The algorithm has been successfully applied in a practical wireless LAN access point.