The opportunistic spectrum access (OSA) over wireless networks, ad hoc wireless networks in particular, opens up use of licensed spectrum to unlicensed users for higher capacity and better commercial values enabling bandwidth-hungry content applications like video services. The existing solution's serious practical problems for the primary and secondary users include fairness, utilisation, collision and unfair spectrum access strategy. In this study the authors propose a new analytical framework for more effective implementing the OSA over ad hoc networks for which we integrate the spectrum access assignment with selective physical layer transmission characteristics enhanced with the service traffic information. For this we first define a distance-tree model to generate an available degree (AD) list for all primary and secondary users. Then, a new fairness-driven utility function is defined to control the spectrum efficiency and fairness for the secondary users. Finally, the authors propose some access strategies for the video applications using the cross-layer design.