Click here to load reader
Click here to load reader
Apr 18, 2018
Topics in Signal Processing
Course ID: EE5359
Interim Report: HEVC Lossless Coding and Improvements
SUBMITTED BY: SUJATHA GOPALAKRISHNAN
STUDENT ID: 1001024145
Table of ContentsACRONYMS3HEVC5Block Diagram HEVC5HEVC Lossless Coding6Block Diagram HEVC Lossless Coding7Basic Definitions7H.264  7Inter Frame7Intra Frame8Loop Filters8De-blocking Filter8Sample Adaptive Offset8Block-Based Angular Intra Prediction8Sample-Based Angular Intra Prediction9Coding Tools9LCU/CTU9Parallel Processing9Entropy Coding9Motion Estimation10Motion Compensation10DCT for HEVC lossless compression11Improved HEVC lossless compression using Two-Stage coding11Algorithm of Sample Based Angular Intra Prediction12Pixel-based averaging predictor13NLM Algorithm14Low-Complexity Pixel wise Predictor Implementation16Test Sequences17Test Sequence 117Test Sequence 218Project Results19Future Work21References21
Association for Computer Machinery Mobile Video
Ad Hoc Groups
Adaptive Interpolation Filter
Adaptive Loop Filter
Advanced Motion Vector Prediction
Adaptive Pre-Interpolation Filter
Application-Specific Integrated Circuit
Advanced Video Coding
Audio Video Standard
British Broadcasting Corporation
Bits per pixel
Context Adaptive Binary Arithmetic Coding
Central Processing Unit
Clean Random Access
Circuits and Systems for Video Technology
Discrete Cosine Transform
Discrete Cosine Transform Interpolation Filters
Directional Discrete Cosine Transform
Digital Signal Processing
Digital Sine Transform
Finite Impulse Response
Field Programmable Gate Array
Frames per second
Graphics Processing Unit
High Definition Range
High efficiency video coding
High Efficiency Video Stream
Hyper Text Transfer Protocol
IEEE Conference on Industrial Electronics and Applications
Institute of Electrical and Electronics Engineers
Integer Discrete Cosine Transform
Intra high efficiency
Internet Protocol Television
IS & T
Information Systems and Technology
International Organization for Standardization
Telecommunication Standardization Sector of the International Telecommunications Union
Image, Video, and Multidimensional Signal Processing
Joint Collaborative Team on Video Coding
Joint Photographic Experts Group
JPEG extended range
Joint Scalable Video Model
Joint Technical Committee
Megabit per second
Modified Directional Discrete Cosine Transform
Mode-Dependent Directional Transform
Multimedia Signal Processing
Moving Picture Experts Group
Most Probable Modes
National Association of Broadcasters
Network Abstraction Layer
Pulse Code Modulation
Peak-to-peak signal to noise ratio
Rate-distortion optimized quantization
Residual Differential Pulse Code Modulation
Real-time Transport Protocol
Sample adaptive offset
Sample based Angular Intra-Prediction
Scalable High Efficiency Video Coding
Scalable Video Coding
Sample based weighted prediction for Enhancement Layer Coding
Signal and Image Processing
Spatially Scalable Video Coding
High Efficiency Video Coding(HEVC)   is avideo compression standard, a successor toH.264/MPEG-4 AVC . HEVC is said to double thedata compressionratio compared to H.264/MPEG-4 AVC  at the same level of video quality .
The design of most video coding standards is primarily aimed at having the highest coding efficiency
HEVC benefits from the use of largerCoding Tree Unit(CTU) sizes.
The HEVC video coding layer uses the same "hybrid" approach used in all modern video standards, starting fromH.261 , in that it uses inter-/intra-picture prediction and 2D transform coding.
The main goal of the HEVC standardization effort is to enable significantly improved compression performance relative to existing standards, in the range of 50% bit rate reduction for equal perceptual video quality  .
Block Diagram HEVC
Figure 1: HEVC Encoder 
Figure 2: HEVC Decoder Block Diagram 
Some differences in HEVC  are coding tree units instead of macro blocks, single entropy coding methods-Context Adaptive Binary Arithmetic Coding (CABAC)  method and features like tiles , wave front parallel processing and dependent slices to enhance parallel processing.
HEVC Lossless Coding
The lossless coding mode of HEVC main profile bypasses transform quantization and in-loop filters as shown in the fig.2 .
Comparing it with non-lossless coding mode, it has smallest quantization parameter value.
Lossless coding mode provides perfect fidelity and average bit rate reduction.
Outperforms the existing lossless compression solution such as JPEG-2000  and JPEG-LS .
It can prevent accumulation of quantization errors in repeated encoding and decoding operations of video editing
In this method it is essential to preserve numerical video data with fewer bits.
DCT coefficients i.e., float-point numbers have to be quantized instead of DCT.
Lossless video coding is used when perfect preservation of video data is required .
It employs Sample Angular-based Intra-Prediction (SAP) .
Same prediction mode signaling method.
Same interpolation method of HEVC.
Uses adjacent neighbors as reference shown in fig.8.
Prediction residuals are coded with the entropy coder in the spatial domain .
Block Diagram HEVC Lossless Coding
Figure 3: HEVC lossless Algorithm Block Diagram 
The blocks that are marked bypass are not being used when implementing a HEVC   lossless algorithm, thereby providing average bit rate reduction.
Basic DefinitionsH.264  
H.264/MPEG-4 AVC    is a block-oriented,motion-compensation based video compression standard.
Aninter frameis a frame in avideo compressionstream which is expressed in terms of one or more neighboring frames. The "inter" part of the term refers to the use ofInter frame prediction.
The term intra-frame refers to the various lossless andlossy compressiontechniques that happens relative to information which is contained only within thecurrent frame andnot relativeto any other frame in the video sequence.
HEVC  specifies two loop filters that are applied sequentially; thede-blocking filter(DBF)  applied first and the sample adaptive offset (SAO) filter applied afterwards. Both loop filters are applied in the inter-picture prediction loop, i.e. the filtered image is stored in the decoded picture buffer (DPB) as a reference for inter-picture prediction.
The DBF is similar to the one used by H.264/MPEG-4 AVC  , but with a simpler design and better support for parallel processing.
DBF first apply horizontal filtering for vertical edges to the picture and only after that does, it apply vertical filtering for horizontal edges to the picture. This allows for multiple parallel threads to be used for the DBF .
Sample Adaptive Offset
The SAO filter is applied after the DBF and is designed to allow for better reconstruction of the original signal amplitudes by applying offsets stored in alookup tablein the bit stream.
Block-Based Angular Intra Prediction
It is a method of computing predicted samples produced by PU when lossless coding is not enabled. It is defined to exploit spatial sample redundancy in intra coded CUs. As shown inthe fig.4, a total of 33 angles are defined for the angular prediction, which can be categorized into two classes: vertical and horizontal angular predictions as illustrated .
Figure 4: Block Based Angular Intra Prediction in HEVC 
Sample-Based Angular Intra Prediction
It is a met