Thanks to the advanced technologies, lots of mobile applications have been developed and introduced. Especially, multimedia applications are receiving more attentions since technology advances can allow expensive and complex computations to be executed in mobile embedded systems. The video communication, often used in multimedia applications, occasionally deals with personal information and even classified information. Thus, the encryption of video data becomes indispensable. However, because video coding and cryptography tasks are very complex, they demand high energy consumption. Energy efficiency is the utmost key factor to be considered in mobile platforms due to the limited battery. In this paper, we conduct various experiments such as configuring parameters of H.263 video codec and those of AES cryptographic algorithms in Android-running smartphones. With the experiments, we investigate trade-offs and implications among video quality, run-time performance, and energy consumption. Based on experimental results obtained from this study, we discuss the methods of minimizing the energy consumption while maximizing the video Quality and the security level for secure mobile video communications.