Multithreading Architecture for Real-Time MPEG-4 AVC/H.264 SVC Decoder

摘要

The inter-layer prediction (ILP) including intra, residual, and motion up-sampling operation in Scalable Video Coding (SVC) significantly increases the compression ratio compared to simulcast. The SVC Codec capable of processing the inter-layer prediction among multiple layers, however, requires much more memory and computational power than single-layer MPEG-4 AVC/H.264 Codec. This paper presents a fast and memory-efficient multithreading architecture for real-time MPEG-4 AVC/H.264 Scalable High profile decoder. Unlike existing approaches where multi-threaded video encoding and decoding have been performed within a frame or among frames, the designed algorithm utilizes inter-layer parallelism based on a group of macroblocks (GOM). Also, improved buffer management can be achieved by the proposed access unit (AU) based decoding architecture for enabling GOM-based inter-layer multithreading architecture. The proposed multithreading architecture has three properties: (1) scalable to the number of SVC layers, (2) no additional coding delay, and (3) no additional memory requirement. Experimental results show that the proposed multithreading architecture speeds up the decoding time of 3-layer extended spatial scalability sequences by about 36% on average, 3-layer coarse grain scalability 50%, and 5-layer medium grain scalability by about 102%, respectively, compared to a single-threaded SVC decoder.