ACRONYMS - The University of Texas at Arlington – UT ... · Web viewDiscrete Cosine Transform Interpolation Filters DDCT Directional Discrete Cosine Transform DSP Digital Signal

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 [1] [2]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

ACRONYMS

2D

Two dimension

3D

Three dimension

ACM MoVid

Association for Computer Machinery Mobile Video

AHG

Ad Hoc Groups

AIF

Adaptive Interpolation Filter

ALF

Adaptive Loop Filter

AMVP

Advanced Motion Vector Prediction

APIF

Adaptive Pre-Interpolation Filter

ASIC

Application-Specific Integrated Circuit

AVC

Advanced Video Coding

AVS

Audio Video Standard

BBC

British Broadcasting Corporation

BD

Bjontegaard Distortion

BL

Base Layer

bpp

Bits per pixel

BS

Boundary Strength

CU

Coding Unit

CI

Confidence Interval

CABAC

Context Adaptive Binary Arithmetic Coding

CPU

Central Processing Unit

CRA

Clean Random Access

CSVT

Circuits and Systems for Video Technology

CU

Coding Unit

DCT

Discrete Cosine Transform

DCTIF

Discrete Cosine Transform Interpolation Filters

DDCT

Directional Discrete Cosine Transform

DSP

Digital Signal Processing

DST

Digital Sine Transform

EC

Error Concealment

FIR

Finite Impulse Response

FPGA

Field Programmable Gate Array

fps

Frames per second

GPU

Graphics Processing Unit

HDR

High Definition Range

HEVC

High efficiency video coding

HEVStream

High Efficiency Video Stream

HTTP

Hyper Text Transfer Protocol

ICIEA

IEEE Conference on Industrial Electronics and Applications

IEEE

Institute of Electrical and Electronics Engineers

INTDCT

Integer Discrete Cosine Transform

intra HE

Intra high efficiency

IPTV

Internet Protocol Television

IS & T

Information Systems and Technology

ISO

International Organization for Standardization

ITU-T

Telecommunication Standardization Sector of the International Telecommunications Union

IVMSP

Image, Video, and Multidimensional Signal Processing

JCTVC

Joint Collaborative Team on Video Coding

JM

Joint Model

JPEG

Joint Photographic Experts Group

JPEG-XR

JPEG extended range

JSVM

Joint Scalable Video Model

JTC

Joint Technical Committee

LR

Low Resolution

Mbit/s

Megabit per second

MC

Motion Compensation

MDDCT

Modified Directional Discrete Cosine Transform

MDDT

Mode-Dependent Directional Transform

ME

Motion Estimation

MJPEG

Motion JPEG

MMSP

Multimedia Signal Processing

MPEG

Moving Picture Experts Group

Mpixel

Megapixel

Mpm

Most Probable Modes

MV

Motion Vector

NAB

National Association of Broadcasters

NAL

NLM

Network Abstraction Layer

Non-Local Means

PCM

Pulse Code Modulation

PSNR

Peak-to-peak signal to noise ratio

PU

Prediction Unit

QP

Quantizer parameter

RD

Rate Distortion

RDOQ

Rate-distortion optimized quantization

RDPCM

Residual Differential Pulse Code Modulation

ROT

Rotational Transform

RTP

Real-time Transport Protocol

SAO

SAP

Sample adaptive offset

Sample based Angular Intra-Prediction

SHVC

Scalable High Efficiency Video Coding

SVC

Scalable Video Coding

SELC

Sample based weighted prediction for Enhancement Layer Coding

SIP

Signal and Image Processing

SSVC

Spatially Scalable Video Coding

TB

Transform Block

TU

Transform Unit

HEVC

High Efficiency Video Coding(HEVC) [1] [2] is avideo compression standard, a successor toH.264/MPEG-4 AVC [22]. HEVC is said to double thedata compressionratio compared to H.264/MPEG-4 AVC [1] at the same level of video quality [2].

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 [1], 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 [10] [11].

Block Diagram HEVC

Figure 1: HEVC Encoder [2]

Figure 2: HEVC Decoder Block Diagram [3]

Some differences in HEVC [1][2] are coding tree units instead of macro blocks, single entropy coding methods-Context Adaptive Binary Arithmetic Coding (CABAC) [15] 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 [4][19].

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 [22] and JPEG-LS [22].

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 [29].

It employs Sample Angular-based Intra-Prediction (SAP) [4].

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 [29].

Block Diagram HEVC Lossless Coding

Figure 3: HEVC lossless Algorithm Block Diagram [4]

The blocks that are marked bypass are not being used when implementing a HEVC [1] [2] lossless algorithm, thereby providing average bit rate reduction.

Basic DefinitionsH.264 [1] [2]

H.264/MPEG-4 AVC [1] [2] [22] is a block-oriented,motion-compensation based video compression standard.

Inter Frame

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.

Intra Frame

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.

Loop Filters

HEVC [1] specifies two loop filters that are applied sequentially; thede-blocking filter(DBF) [4] 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.

De-blocking Filter

The DBF is similar to the one used by H.264/MPEG-4 AVC [1] [2], 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 [1].

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 [14].

Figure 4: Block Based Angular Intra Prediction in HEVC [4]

Sample-Based Angular Intra Prediction

It is a met