Multimedia applications require significantly higher bandwidth than conventional textual applications. Furthermore, multimedia stream requires time sensitive and involves high-energy consumption, which become more challenging on resource constrained networks such as wireless multimedia sensor network (WMSN). As a result, developing an energy efficient algorithm to prolong the network lifetime is the main reoccurring issue in WMSN. Although the duty cycling mechanism has been proven to be an efficient solution for energy saving in various WSN applications, the tradeoff between energy efficiency and quality of service (QoS) on WMSN remains striking. In this article, an adaptive dynamic duty cycle mechanism for energy-efficient medium access control (ADE-MAC) is proposed for WMSNs. ADE-MAC uses a unique asynchronous duty cycle approach to schedule the sleep pattern of each sensor node which can be adapted according to the incoming traffic rate and queuing delay at each node. In the proposed system, the overhead of synchronization is avoided because every node has its own scheduling sleep, and the only sender node must wake up the receiver nodes by using preambles packets. The findings that result from comprehensive simulation show that ADE-MAC outperforms the baseline approaches in term of delivery ratio by 12%, less packet overhead by 28%, less end-to-end delay by 19%, and less power consumption by 41% compared to the baseline mechanisms.