EnergyEfficiency Exploration of Memory Hierarchy using NVMs for HEVC Motion Estimation Efficient video coding techniques applied by modern video encoders  e.g. the High Efficiency Video Coding (HEVC)  enable the handling and sharing of digital videos content. The applied complex dataintensive algorithms, as the Motion Estimation (ME), pose severe constraints in terms of memory communication and energy consumption, especially for batterypowered devices. Thus, an evaluation using efficient memory hierarchies, exploring multiple cache configurations and the use of nonvolatile memories (NVMs) as main memory, was performed. Our evaluation considered TZS algorithm, encoding FHD videos, under 32 different cache configurations, combined with three main memory technologies: DRAM, STTRAM, and ReRAM. The best cache configurations were selected in terms of lowest total energy consumption, moreover, different energy savings were achieved using nonvolatile memories as main memory, varying from 33.4% to 57.6%, for STTRAM and ReRAM, respectively, with ReRAM presenting the best energy results and reducing the optimal cache size.

Energy Savings with NonVolatile Memory System for High Definition Video Encoders Energy consumption is a crucial factor that constrains applications running on different computer architectures and platforms. Video encoding is no exception and it is relevant in mobile platforms. In the video encoders memory system the energy consumption is mainly due to the increase in bandwidth and the storage of the reference frames used in the encoding process of the video. The motion estimation stage is responsible for this process, which requires large amount of access to the internal and external memories of the chip, which leads to high energy consumption for video encoding. This paper presents an evaluation of different schemes with data reuse using different memory technologies in the memory hierarchy, including nonvolatile memories (NVM), such as: PCRAM, ReRAM and STTRAM. Our results show that schemes composed by DRAM and NVM present energy savings of 43%, on average, when compared to conventional DRAM and SRAM schemes. Furthermore, the best results were obtained with ReRAM as external memory and ReRAM or STTRAM as the scratchpad memory (SPM), such configurations reach a total memory energy consumption reduction of 89% and 87%, respectively, when compared to the conventional configuration of external DRAM and onchip SRAM memories.