Exploiting Approximate SRAM for Energy-Efficient Integer Motion Estimation on VVC Encoders

Video coding is a critical technology for enabling many modern applications. However, the high complexity of state-of-the-art encoders leads to energy consumption challenges, particularly in memory systems. This paper proposes an integer motion estimation (IME) system using approximate SRAM memories to enhance the energy efficiency of VVC encoders. The approximate SRAM memories are employed for both the current block and the search area buffers by reducing the supply voltage. The proposed IME system is evaluated using a customized tool that simulates the approximation effects on both buffers based on real energy measurements from a 28nm SRAM. This tool is integrated with VVenC, a fast VVC implementation, to assess the impact on coding efficiency and energy consumption. Experimental results show that the IME system using approximate SRAM can reduce energy consumption in reading operations by up to 55%, with a low impact on coding efficiency.