Analysis and design of macroblock pipelining for H.264/AVC VLSI architecture
This paper presents a new macroblock (MB) pipelining scheme for H.264/AVC encoder. Conventional video encoders adopt two-stage MB pipelines, which are not suitable for H.264/AVC due to the long encoding path, sequential procedure, and large bandwidth requirement. According to our analysis of encoding process, an H.264/AVC accelerator is divided into five major functional blocks with four-stage MB pipelines to highly increase the processing capability and hardware utilization. By adopting shared memories between adjacent pipelines with sophisticated task scheduling, 55% of the bus bandwidth can be further reduced. Besides, hardware-oriented algorithms are proposed without loss of video quality to remove data dependencies that prevent parallel processing and MB pipelining. The H.264/AVC Baseline Profile Level Three encoder, which requires computational complexity of 1.8 tera-instructions per second (TIPS), is successfully mapped into hardware with our MB pipeline scheme at 100 MHz.