Early termination schemes for fast intra mode decision in High Efficiency Video Coding

The emerging High-Efficiency Video Coding video coding standard has shown the significant coding performance improvement compared to the H.264/AVC with the cost of huge complexity increase. Hence, HEVC fast encoding algorithms are highly demanded for real-time applications. In this paper, we propose several early termination schemes for fast intra prediction in HEVC. More specifically, variation of coding mode costs are used to terminate current coding unit (CU) mode decision as well as TU size selection, where the CU costs are derived at the rough mode decision phase using Hadamard transform. Neighboring modes' costs are also used to skip full rate-distortion optimized quantization (RDOQ). For all available test sequences provided by the JCT-VC, it demonstrates about 32% encoding time reduction for All Intra configuration with BD-RATE increase about 1.1%. Our proposal is complementary to some of other fast intra prediction methods such as fast rough mode decision. We expect more encoder speedup by integrating our method with other published works.