A low-cost VLSI architecture of multiple-Size IDCT for H.265/HEVC

In this paper, we present an area-efficient 4/8/16/32-point inverse discrete cosine transform (IDCT) architecture for a HEVC decoder. Compared with previous work, this work reduces the hardware cost from two aspects. First, we reduce the logical costs of 1D IDCT by proposing a reordered parallel-in serial-out (RPISO) scheme. By using the RPISO scheme, we can reduce the required calculations for butterfly inputs in each cycle. Secondly, we reduce the area of transpose architecture by proposing a cyclic data mapping scheme that can achieve 100% I/O utilization of each SRAM. To design a fully pipelined 2D IDCT architecture, we propose a pipelining schedule for row and column transform. The results show that the normalized area by maximum throughput for the logical IDCT part can be reduced by 25%, and the memory area can be reduced by 62%. The maximum throughput reaches 1248 Mpixels/s, which can support real-time decoding of a 4K × 2K 60 fps video sequence.