Low-complexity transform and quantization in H.264/AVC

TLDR: The 4/spl times/4 transforms in H.264 can be computed exactly in integer arithmetic, thus avoiding inverse transform mismatch problems and minimizing computational complexity, especially for low-end processors.

Abstract: This paper presents an overview of the transform and quantization designs in H.264. Unlike the popular 8/spl times/8 discrete cosine transform used in previous standards, the 4/spl times/4 transforms in H.264 can be computed exactly in integer arithmetic, thus avoiding inverse transform mismatch problems. The new transforms can also be computed without multiplications, just additions and shifts, in 16-bit arithmetic, thus minimizing computational complexity, especially for low-end processors. By using short tables, the new quantization formulas use multiplications but avoid divisions.