In this work, we address the complexity of the most time consuming module of High Efficiency Video Coding (HEVC) Intra-encoding, i.e. The Intra prediction generation. We reduce the computational complexity by estimating the candidates list (most probable Intra prediction modes), using content- and priority-driven gradient detection and hierarchically gathering the results of previous computations. This complexity reduction scheme is adaptive and can be controlled, depending upon the requirements, e.g. frame rate and video quality. On average, our scheme is capable of delivering 44% more time savings than the state-of-the-art scheme for fast Intra mode estimation.