Coding Tree Early Termination for Fast HEVC Transrating Based on Random Forests

Video transrating has become an essential task in streaming service providers that need to transmit and deliver different versions of the same content for a multitude of users that operate under different network conditions. As the transrating operation is comprised of a decoding and an encoding step in sequence, a huge computational cost is required in such large-scale services, especially when considering the use of complex state-of-the-art codecs, such as the High Efficiency Video Coding (HEVC). This work proposes an early-termination method for complexity reduction of the HEVC transrating based on Random Forests, which use features obtained from the HEVC decoding process to accelerate the coding tree decisions during the re-encoding process. Experimental results show that the proposed method achieves an average transrating time reduction of 47.09% at the cost of a negligible bitrate increase of 0.292%.