Video Compression Standards for High Definition Video : A Comparative Study Of H.264, Dirac pro

And AVS P2

By Sudeep GangavatiEE5359 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).

0

Sub-macroblock partitions

0

1 0 1

0 1

2 3

0 0

1 0 1

0

2

1

3

1 macroblock partition of 16*16 luma samples and

associated chroma samples

Macroblock partitions

2 macroblock partitions of 16*8 luma samples and

associated chroma samples

4 sub-macroblocks of 8*8 luma samples and

associated chroma samples

2 macroblock partitions of 8*16 luma samples and

associated chroma samples

1 sub-macroblock partition of 8*8 luma samples and

associated chroma samples

2 sub-macroblock partitions of 8*4 luma samples and

associated chroma samples

4 sub-macroblock partitions of 4*4 luma samples and

associated chroma samples

2 sub-macroblock partitions of 4*8 luma samples and

associated chroma samples

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.186-216)”, Special issue on “ Emerging H.264/AVC video coding standard”, J. Visual Communication and Image Representation, vol. 17, pp.186-216, April 2006.[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.560-576, July 2003.[3] T. Sikora, “Digital video coding standards and their role in video communications”, Signal Processing for Multimedia, J.S. Byrnes (Ed.), IOS press, pp. 225-251, 1999. [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 7-9 2010, pp. 1-8, March 2010.[5]Z. Wang and A.C. Bovik, “A universal image quality index”, IEEE Signal Processing Letters,Vol.9, pp. 81-84, March 2002.[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. 679-690, July 2005.[8] “ The Dirac web page” :http://www.bbc.co.uk/rd/projects/dirac/intro.shtml[9] “Dirac Codec Wiki Page ” at http://en.wikipedia.org/wiki/Dirac(codec)[10]“Dirac Pro web page” at http://www.bbc.co.uk/rd/projects/dirac/diracpro.shtml [11] “Video on the web “ a http://etill.net/projects/dirac_theora_evaluation/[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 : http://iphome.hhi.de/suehring/tml/ [14] H.264 decoder: http://www.adalta.it/Pages/407/266881_266881.jpg [15] W. Gao et al, “AVS - The Chinese next-generation video coding Standard” NAB, Las Vegas, 2004. [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.310-314, May 2006. [17] AVS China part 2 video software, password protected : ftp://124.207.250.92/ [18] S. Swaminathan and K.R. Rao, “Multiplexing and demultiplexing of AVS CHINA video with AAC audio,” TELSIKS 2011, Nis, Serbia, 5-8 Oct. 2011. [19] Dirac Pro Software : http://diracvideo.org/download/ [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, 2008. [21] T. Davies, “The Dirac Algorithm”: http://dirac.sourceforge.net/documentation/algorithm/, 2008. [22] Dirac video codec – A programmer's guide: http://dirac.sourceforge.net/documentation/code/programmers_guide/toc.htm [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.635-654, No.4, 2011.