This paper proposes Dynamic Thermal Management (DTM) based on a dynamic voltage and frequency scaling (DVFS) technique for MPEG-4 decoding to guarantee thermal safety while maintaining a quality of service (QoS) constraint. Although many low-power and low-temperature multimedia playback techniques have been proposed, most of them are impractical in real-time and have several restricting assumptions. Multimedia data consists of several frames requiring different decoding efforts. Since both temperature and performance of a multimedia system are affected by the complexity of scenes, our main idea is to use the information on scene complexity to find an appropriate frequency. In order to predict the complexity of the current scene, we extract information from the previous group of pictures (GOP) using feedback control with a display buffer. Experimental results with twelve movies show that our DTM scheme guarantees the threshold of temperature (70◦C) while maintaining 0% frame miss ratio. Also, our DTM scheme decreases the average temperature by up to 13% without any additional hardware and playback latency