Video Coding Standard 2013 02 12 Jaewon Suh

Video Coding Standard 2013. 02. 12 Jaewon Suh

Contents n n n Compression The scope of video coding standardization Video coding standards General concept of video coding structure Research topics n n n Fast coding unit decision for HEVC Autonomous vehicle Future plan n Reversible enhancement digital image processing Visual Communication Lab.

Compression n What is compression? n n Reducing the amount of data by elimination of redundancy Why we need the compression? n n Some restriction on the available bandwidth Large amount of video data n n n SD: 640 480 (24 bits) = 7, 372, 800 bits HD: 1920 1080 (24 bits) = 49, 766, 400 bits n 20 Mbps for HDTV Lossless & Lossy compression n n Lossless: decoded data = original data Lossy: decoded data ≠ original data n Video Coding Standard Visual Communication Lab.

Scope of Video Coding Standardization n n Only restrictions on the bitstream and syntax Focusing on the Decoder n n n Permits the optimization of encoding procedure Requires complexity reduction for implementation No guarantee of visual quality of the decoder Source Destination Pre-Processing Encoding Transmission Errors Post-Processing & Error Recovery Decoding Visual Communication Lab.

Video Coding Standards ITU-T H. 263 (1995/96) H. 263+ (1997/98) H. 261 (1990) ISO/IEC (H. 262) (1994/95) MPEG-2 H. 263++ (2000) MPEG-4 v 1 (1998/99) FTV (2007) MPEG-4 v 3 (2001) 95 00 H. 265 (2010) KTA H. 264 FRExt (v 7) SVC (v 8) (2007) MVC (2009) MPEG-4 v 2 (1999/00) MPEG-1 (1993) 90 H. 264/AVC (JVT ) (2003) MPEG-4 part 10 05 H. 265/HEVC (JCT-VC) (2013) UHD: 8192 4320 3 DVC (2009 ~) 10 13 Visual Communication Lab.

General Video Coding Structure

Redundancy of Video Data n n Hybrid coding structure of ME/MC and DCT Redundancy n Temporal n n Spatial n n ME/MC DCT & Q Statistical n VLC Visual Communication Lab.

Hierarchy Structure for Video Sequence GOPn+1 GOPn+2 Slice time Macroblock (16 16) GOPn Block (8 8) Picture Y 2 Slice Y Cr 16 Y 0 Y 1 Y 3 Cb Cr 8 8 16 Cb Visual Communication Lab.

Group of Pictures (GOP) GOP Length N=12, M=3 0 1 2 3 4 5 6 7 8 9 9 7 10 11 12 Display Order 0 2 3 1 5 6 4 8 11 12 10 Encoding Order I-picture P-picture B-picture Visual Communication Lab.

Temporal Redundancy n n Similar scenes between nearby images of the video sequence Remove the similarity between successive frames Visual Communication Lab.

Motion Estimation & Motion Compensation n Process of obtaining the motion vector (MV) － Previous Picture Current Picture Motion Compensated Picture Search Area Residual Data Visual Communication Lab.

Spatial Redundancy n n Similar intensities between adjacent pixels on the same picture Taking advantage of similarity among the neighboring pixels Visual Communication Lab.

Discrete Cosine Transform (DCT) n 8× 8 DCT where for u=0, Cu=1 otherwise for v=0, Cv=1 otherwise DCT Visual Communication Lab.

Quantization n Lossy Coding 8× 8 Coefficient 8× 8 DCT Coefficient Quantized Coefficient DCT Q Visual Communication Lab.

Statistical Redundancy n VLC Coding for DC Value n n 4 Blocks in one Macroblock Difference coding 20 23 21 25 20 3 -2 4 Make a symbol for each coefficient Visual Communication Lab.

VLC Coding for AC Value n n AC Coefficient is ‘ 0’ or not Run-length Coding n n n Run: the number of zeros Level: magnitude of the nonzero value EOB: indication of whether the current nonzero value is the last nonzero value in the block Zigzag Scanning Run-length Coding 0 -2 -1 -1 -1 0 0 … (1, 2) (0, 1) (2, 1) EOB Symbol Look up the table Visual Communication Lab.

High Efficiency Video Coding n The next generation of video coding standard n n Aim of HEVC n n n HEVC standard will be finished by the end of 2013. Two times higher coding efficiency than H. 264/AVC. 40~45% data compression ratio when compared to H. 264/AVC. Advanced coding algorithms n n Inter mode n Recursive quad-tree structured CU (coding unit) system n Variable PU (prediction unit) ME/MC with multiple reference Intra mode n 35 Spatial predictions for intra CU n 4 4 integer discrete cosine transform (DCT) Content adaptive binary arithmetic coding Rate-distortion optimization Visual Communication Lab.

Fast Coding Unit Decision Algorithm for HEVC

Mode Decision in HEVC n MB CU (Coding unit) n n In order to determine the best coding mode, CU encoding should be implemented 85 times according the block number. Unit for ME PU (Prediction unit) n In order to encode one CU, the various PU mode predictions are performed n Intra N×N prediction is performed only when current CU size N is 8 Visual Communication Lab.

Proposed Mode Decision Algorithm n n We suggest a fast CU decision algorithm based on Inter and Intra PU termination using two methods Early Inter PU termination n n If current inter PU is satisfied with our two conditions, the next PU process is terminated in the current CU n If CBF of the Inter PU is zero for one luminance and two chrominances n If RD cost of the Inter PU is lower than the weighed moving averaged SKIP mode RD costs Intra mode skip decision n If the number of zero in Cb(i, j) which is obtained from inter PU prediction is three or more, then we skip the Intra PU encoding Visual Communication Lab.

Autonomous vehicle

Korea Autonomous Vehicle Contest n n n Clothoid team: Automatic control, Navigation, VC Lab. Given information: Way point of the road Run the full competition course passing through some missions n n Detection of traffic lights, obstacle, toll bar, pedestrian Avoiding complex obstacles, passing the low speed vehicle Parking If the car fails a mission, 2 minutes penalty Visual Communication Lab.

Reversible Enhancement Digital Image Processing

Histogram Equalization Histogram of original image Original Image Histogram of histogram equalized image Histogram Equalization Visual Communication Lab.

Reversible Histogram Equalization Histogram of original image Original Image Histogram of reversible histogram equalized image Reversible Histogram Equalization Visual Communication Lab.

Reversible Histogram Equalization Visual Communication Lab.

Reversible Histogram Equalization Visual Communication Lab.

Reversible Histogram Equalization Visual Communication Lab.