Implementation of High Efficient CAVLC Encoder for H.264/AVC

This paper proposes the design and VLSI implement of high efficient Context-based Adaptive Variable Length Coding (CAVLC) encoder which adopted a modified Variable Length Coding (VLC) look up table technique and parallel processing. The proposed CAVLC encoder used upper and under buffer as input buffer to perform zigzag scanning with both way ordering. Because of this, the proposed CAVLC encoder can be read and write concurrently. Moreover, we design the CAVLC encoder procedure with parallel processing which uses two generators for information signals and control signals to operate CAVLC modules such as a coeff_token (TotalCeff and TrailingOnes) module, a level module, a total_zeros module, and a run_before module. The proposed CAVLC is prototyped in Verilog-HDL, implemented and synthesized with megnachip 0.18 µm CMOS tech. The synthesis result shows that the gate count is about 12K with the clock constraint of 140Mhz. The proposed CAVLC encoder is suitable for real-time video applications.