ICT fixed point error performance analysis

The DCT is the most popular transform in video coding. However, two recently developed video coding standards, H.264 and AVS, adopt order-4 and order-8 integer cosine transforms (ICT) respectively. The ICTs adopted in these standards have simpler implementation but their compaction ability is similar to that of DCT. The two ICTs are simpler because they can be implemented using multiplication of small integers while the DCT requires multiplication of irrational numbers. In this paper, the fixed-point error performance of the DCT and the ICT, adopted by the AVS, are analyzed and compared. Both theoretical and experimental results show that the ICT system produces more accurate pixels than the DCT system when the transform coefficients are represented using the same number of bits.