Reducing Complexity on Intra Mode Decision in Video Coding: A Review
Ei Ei Tun, Supavadee Aramvith · IEEE Access · 2026
This article surveys low-complexity techniques for intra mode selection in modern video coding standards. The objective is to consolidate knowledge of intra prediction methods and clarify their computational impact in High Efficiency Video Coding (HEVC) and its successor, Versatile Video Coding (VVC). The survey reviews the evolution of intra coding frameworks, outlines the growing complexity of prediction modes and partitioning structures, and analyzes representative solutions. These include statistical, optimization-based, learning-driven, and hardware-oriented methods, each designed to reduce encoding time while maintaining rate–distortion performance. Trade-offs between complexity reduction and coding efficiency are highlighted, along with the scalability challenges of applying fast algorithms at the coding tree unit level. The article concludes by identifying open challenges and proposing future research directions, providing a consolidated reference for advancing efficient intra coding in HEVC and VVC.