With the deployment of Audio-Video (AV) services and the flexibility offered by wireless networks, there is more and more an increasing interest on defining more reliable multicast mechanisms. Towards this end, the IEEE Task Group aa (TGaa) is currently working on the definition of the IEEE802.11aa amendment. The standardization efforts in this area aim to develop efficient QoS mechanisms by keeping in mind that any new mechanism should: 1) properly interoperate with the already existing unicast mechanisms; and 2) provide the robustness required by AV applications. In order to meet the former, the efforts are focusing on amending the existing multicast standard while to meet the latter there is a need of better understanding the stringent requirements of AV streaming applications. In this work, after reviewing the amendments introduced by the IEEE 802.11aa, we carried out an evaluation of the proposed multicast mechanisms when supporting video streaming applications. The main contribution of this work focuses therefore on evaluating the QoS parameters that the TGaa has taken into account to define the proposed mechanisms. © 2012 IEEE.