Frame-Based and Subpicture-Based Parallelization Approaches of the HEVC Video Encoder

Abstract

Abstract:The most recent video coding standard, High Efficiency Video Coding (HEVC), is able to significantly improve the compression performance at the expense of a huge computational complexity increase with respect to its predecessor, H.264/AVC. Parallel versions of the HEVC encoder may help to reduce the overall encoding time in order to make it more suitable for practical applications. In this work, we study two parallelization strategies. One of them follows a coarse-grain approach, where parallelization is based on frames, and the other one follows a fine-grain approach, where parallelization is performed at subpicture level. Two different frame-based approaches have been developed. The first one only uses MPI and the second one is a hybrid MPI/OpenMP algorithm. An exhaustive experimental test was carried out to study the performance of both approaches in order to find out the best setup in terms of parallel efficiency and coding performance. Both frame-based and subpicture-based approaches are compared under the same hardware platform. Although subpicture-based schemes provide an excellent performance with high-resolution video sequences, scalability is limited by resolution, and the coding performance worsens by increasing the number of processes. Conversely, the proposed frame-based approaches provide the best results with respect to both parallel performance (increasing scalability) and coding performance (not degrading the rate/distortion behavior).

Fast and Accurate Solution of Integral Formulations of Large MQS Problems Based on Hybrid OpenMP–MPI Parallelization

“…More recently, this problem has been addressed by using hybrid parallel programming paradigms, like those that adopt both a parametrized communication paradigm, such as the message passing interface, MPI [7], and an application programming interface, such as OpenMP [8,9]. Such a hybrid programming approach has been used in several fields, such as computational fluid dynamics [10,11], chemical simulations [12,13], geotechnics [14], high efficiency video coding [15], and electromagnetic simulations [16][17][18], due to its very interesting performance [19]. As pointed out in [19,20], the advantages of using a hybrid OpenMP-MPI programming approach are many, as follows: (i) suitability to the architecture of modern supercomputers, with interconnected shared memory nodes; (ii) improved scalability; (iii) optimization of the total consumed memory; (iv) reduction in the number of MPI processes.…”

Spatio-Temporal Parallelization Scheme for HEVC Encoding on Multi-Computer Systems

“…In [6]- [8], process level parallelization was implemented by distributing the video temporally to different encoder instances in group of pictures (GOPs). Thread level parallelization was achieved with tiles and slices in [9], [10]. In [11], the encoding process was parallelized in all three parallelization levels simultaneously.…”