Video Compression Standards for High Definition Video : A Comparative Study Of H.264, Dirac pro And AVS P2 By Sudeep Gangavati EE5359 Spring 2012, UT Arlington

Proposal The goal – to compare H.264/AVC, AVS P2 and Dirac Pro Video quality assessment – MSE, PSNR, SSIM

H.264/AVC Features The most widely used video coding standard Fig. 1 Video coding standards evolution [12]

Features Motion compensated coding structure Picture  slices  MBs  subMBs  blocks  pixels. This is shown in Figure 3. Only 4:2:0 chroma format was supported earlier and 4:2:2, 4:4:4 were added later. This is shown in Figure 2. I, P and B slices Derived slices SI and SP

Fig 2. 4:2:4, 4:2:2, 4:4:0 sampling patterns

Fig 3. H.264 syntax

Profiles and levels Main Profile Baseline Profile Extended Profile High Profile

H.264 Profiles Fig.4 H.264 profiles [1]

H.264 Encoder Fig. 5 Encoder structure for H.264 [2]

H.264 Decoder Fig.6 Decoder structure of H.264 [2]

Intra and Inter Predictions Intra Prediction : Uses spatial prediction to reduce spatial redundancy. 4 X 4 luma – 9 modes 16 X 16 luma – 4 modes 8 X 8 luma- 9 modes

Intra prediction modes for 4X4 luma Fig.7(a) Intra prediction modes [6] The samples above and to the left, labelled A-M in Figure 7 have previously been encoded and reconstructed and are therefore available in the encoder and decoder to form a prediction reference.

Intra Prediction Modes for 16x16 luma Again the previously encoded samples directly above and to the left of the macroblock have been reconstructed and are used for the prediction Fig 7 (b) Intra prediction modes for 16x16 luma [6]

Inter prediction Uses motion estimation and motion compensation (MC). Fig.8 H.264 Inter prediction [5]

De-blocking filter[5] Is used to reduce the blocking artifacts. Since the filter is present in the loop, it prevents the propagation of the blocking artifacts. Fig. 9 Boundaries in a macroblock to be filtered (luma boundaries shown with solid lines and chroma boundaries shown with dotted lines) [1]

AVS China[7] AVS-Audio Video Standard Standardization includes system, audio, video and digital copyright management. Goal – to achieve coding efficiency with reduced complexity.

AVS Parts [3] Fig. 10 AVS China parts [3]

AVS P2 Encoder [7] Fig. 11 AVS part 2 encoder [7]

AVS P2 decoder Fig 11 (a) AVS P2 decoder block diagram [7]

Intra Prediction in AVS[7] Spatial prediction is used in intra coding in AVS part 2. The Intra prediction is based on 8x8 block The intra prediction method is derived from the neighboring pixels in left and top blocks

Intra Prediction contd. Fig.12 (a) Five different modes for intra luminance prediction[16]

Inter prediction [16] Inter prediction in AVS is by motion compensation and motion estimation [16]. As shown in the Figure 12 (b), the macroblock can have 16 x 16, 8 x 16, 16 x 8 or 8 x 8 [16]. Fig 12 (b) Macroblock sizes [16]

Dirac pro Dirac is a video codec originally developed by BBC This technique is used from web streaming of videos to HD TV applications to storage of content. Dirac can compress any resolution picture The encoder and decoder diagrams are shown in Figure 13 (a) and (b) respectively.

Figure 13 (a) Dirac encoder[8] Figure 13 (b) Dirac decoder[8] Dirac encoder and decoder :

Dirac pro features[7] Dirac pro is intra-coding only a version of Dirac Mainly optimized for video production Intended for high quality applications

Dirac pro Features Dirac pro supports the following technical aspects [9]: Intra-frame coding only 10 bit 4:2:2 No subsampling Lossless or visually lossless compression Low latency on encode/decode Support for multiple HD image formats and frame rates Low complexity for decoding

References [1] Soon-kak Kwon, A. Tamhankar and K.R. Rao, “Overview of H.264 / MPEG-4 Part 10 (pp )”, Special issue on “ Emerging H.264/AVC video coding standard”, J. Visual Communication and Image Representation, vol. 17, pp , April [2] T. Wiegand, G. Sullivan, G. Bjontegaard and A. Luthra, “Overview of the H.264/AVC video coding standard,” IEEE Trans. on Circuits and Systems for Video Technology, vol. 13, pp , July [3] T. Sikora, “Digital video coding standards and their role in video communications”, Signal Processing for Multimedia, J.S. Byrnes (Ed.), IOS press, pp , [4] K. R. Rao, and D. N. Kim, “Current video coding standards: H.264/AVC, Dirac, AVS China and VC-1,” IEEE 42nd Southeastern symposium on system theory (SSST), March , pp. 1-8, March [ 5]Z. Wang and A.C. Bovik, “A universal image quality index”, IEEE Signal Processing Letters,Vol.9, pp , March [6] Iain Richardson, “ The H.264 advanced video coding standard”, Second Edition,Wiley, 2010 [7] L. Yu et al, “An Overview of AVS-Video: tools, performance and complexity”, Visual Communications and Image Processing, Proc. of SPIE, vol. 5960, pp , July [8] “ The Dirac web page” : [9] “Dirac Codec Wiki Page ” at [10]“Dirac Pro web page” at [11] “Video on the web “ a [12] J.Lou “Advanced video codec optimization techniques”, Doctoral Dissertation, Electrical Engineering Department, University of Washington, August 2009

References [ 13] H.264 AVC JM Software : [14] H.264 decoder: [15] W. Gao et al, “AVS - The Chinese next-generation video coding Standard” NAB, Las Vegas, [16] X. Wang et al., “Performance comparison of AVS and H.264/AVC video coding standards” J. Comput. Sci. & Technol., vol.21, No.3, pp , May [17] AVS China part 2 video software, password protected : ftp:// /ftp:// / [18] S. Swaminathan and K.R. Rao, “Multiplexing and demultiplexing of AVS CHINA video with AAC audio,” TELSIKS 2011, Nis, Serbia, 5-8 Oct [19] Dirac Pro Software : [20] M. Tun, K.K. Loo and J. Cosmas, “Semi-hierarchical motion estimation for the Dirac video codec,” 2008 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, pp.1–6, March 31-April 2, [21] T. Davies, “The Dirac Algorithm”: [22] Dirac video codec – A programmer's guide: [23] A. Ravi and K.R. Rao, “Performance analysis and comparison of the Dirac video codec with H.264 / MPEG-4 Part 10 AVC,”IJWMIP, vol.4, pp , No.4, 2011.