Low Complexity Transform and Quantization in H.264/AVC Speaker: Pei-cheng Huang 2005/6/2

Low-Complexity Transform and Quantization in H.264/AVC 1 Outline Introduction to transform and quantization in H.264 Details of transform procedure Details of quantization procedure

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 2 Reference Henrique S. Malvar, Antti Hallapuro, Marta Karczewicz, and Louis Kerofsky, “Low-Complexity Transform and Quantization in H.264/AVC,” IEEE Transactions on Circuits and Systems for Video Technology, Vol. 13, No. 7, July 2003 Iain E. G. Richardson, “H.264 and MPEG-4 Video Compression,” Wiley, 2003, ISBN

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 3 H.264 block diagram

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 4 Transform procedure in H.264 Discrete Cosine Transform (DCT) 4x4

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 5 Implementation problems How to express real numbers? System complexity

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 6 DCT

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 7 DCT Cosines in real number format: Orthogonal matrix H -1 = H T

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 8 Fixed point DCT in TML Very similar to original DCT Orthogonal rows Constant row norm Higher dynamic range –Max value of Hx = 52A

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 9 Fixed point DCT in H.264 Also has orthogonal rows Non-constant row norm

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 10 Dynamic range of low complexity DCT Max value of DCT coefficients = 6A

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 11 Inverse Transform Max value of DCT coefficients = 4A

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 12 Influence of non- constant row norm

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 13 Cancel the scale factors

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 14 Low complexity DCT butterfly diagram

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 15 Quantization

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 16 Avoid divisions

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 17 Quantization in H.264

2005/6/2Low-Complexity Transform and Quantization in H.264/AVC 18 Performance Coding gain 5.39 dB --> 5.38 dB PSNR 0.01 dB loss Significantly lower complexity