Optimal Word Length Study on DCT and IDCT Algorithms

摘要

Accuracy and efficiency are both important for DCT and IDCT algorithms. Based on our previous work on the dynamic range analysis for DCT and IDCT computation, in this paper we give detailed analysis of the data range during 2D DCT and IDCT computation. Then the maximum number of bits required for every computation pass during the DCT and IDCT computation is determined. Further, an optimal word length strategy for a widely used VLIW oriented DCT and IDCT algorithm is proposed. Utilizing this method, at most 7 bits are extracted to represent the fractional part of data during 16-bit word length computation.