Jae Jeong Hwang

H.264/MPEG-4 Advanced Video Coding

Similar to AVS China ( Chap. 3), the profiles, levels and functionalities of H.264/AVC are described. The roles of various blocks in the encoder and decoder, from a video compression view point, are addressed. The similarities and differences between AVS China and H.264/AVC can be observed.

High Efficiency Video Coding(HEVC)

HEVC the latest standard is presented. Comparison with H.264/AVC ( Chap. 4) is cited. The focus is on overview of HEVC rather than a detailed description of tools and techniques that constitute the encoder. A plethora of projects listed at the end challenges the implementation and futher research related to HEVC.

Two-Dimensional Discrete Fourier Transform

Two-dimensional DFT has applications in image/video processing. The extension from 1-D to 2-D for the DFT is straightforward.

Vector-Radix 2D-FFT Algorithms

Similar to radix-2 FFT, a vector-radix 2-D FFT can be developed for multidimensional signals. As is the case for radix-2 FFT, the vector radix algorithms can be developed based on both DIT and DIF [SR2, DS1, B39]. Also DIT and DIF can be mixed in the same algorithm. In fact, vector-radix algorithms exist for any radix i.e., radix-2, radix-3 [A14], radix-4 etc. As an illustration, vector radix FFT for a 2-D signal based on both DIT and DIF will be developed. It is then straight forward to extend this technique to all the other vector radix algorithms. As with all the fast algorithms, the advantages of vector radix 2-D FFT are reduced computational complexity, reduced memory (storage) requirements and reduced errors due to finite bit size arithmetic. Vector radix algorithms are much more amenable to vector processors.

Video Coding Standards and Video Formats

Video formats, conversions among RGB, Y, Cb, Cr, and YUV are presented. These are basically continuation from Chap. 1 and thus complement the topics discussed in Chap. 1.

VP6 Video Coding Standard

Encoder/decoder details on VP6 developed by On2 Technologies are provided. Similarities related to functionalities between H.264 ( Chap. 4) and VP6 are highlighted and differences such as golden frames are pointed out. Resources related to VP9 open source video codec by Google (Google acquired On2 Technologies in 2010) are also addressed.

The VC-1 Video Coding

As with other codecs, encoder/decoder details on VC-1 are described. VC-1 is an SMPTE standard based on WMV9 developed by Microsoft. H.264/AVC to VC-1 transcoder is outlined. The intra frame coding only of Dirac ( Chap. 7) is adopted by SMPTE as VC-2.

Integer Fast Fourier Transform

Since the floating-point operation is very expensive, numbers are quantized to a fixed number of bits. The number of bits at each internal node in the implementation of FFT is fixed to a certain number of bits. Denote this number as N n . The most significant bits (MSBs) of the result after each operation is kept up to N n bits, and the tail is truncated. Thus this conventional fixed-point arithmetic affects the invertability of the DFT because DFT coefficients are quantized.

Discrete Fourier Transform

Colophon An annotatable worksheet for this presentation is available as Worksheet 18 (worksheet18). The source code for this page is dft/1/dft.ipynb (https://github.com/cpjobling/eg-247textbook/blob/master/content/dft/1/dft.ipynb). You can view the notes for this presentation as a webpage (HTML (https://cpjobling.github.io/eg247-textbook/dft/1/dft.html)). This page is downloadable as a PDF (https://cpjobling.github.io/eg-247-textbook/dft/1/dft.pdf) file.