Video Compression (cont.) Lecture # 6 Shahab Baqai LUMS Outline - PowerPoint PPT Presentation

CS 584 / CMPE 584 Multimedia Communication Video Compression (cont.) Lecture # 6 Shahab Baqai LUMS

Outline � Scalable video coding � Overview of current video compression standards – What do the standards specify? – Frame-based video coding: MPEG-1/2/4, H.261/3/L – Object-based video coding: MPEG-4 � Examine MPEG-4 as case-study of object-based video coding – Scope, desired functionalities – Video representation and coding – Individual arbitrarily shaped objects – Scene description for composing individual objects to form scene 2

3 Scalable video coding

4 Scalable Video Coding

5 Example of Scalable Coding

Scalable Video Coding (cont.) 6

Scalable Coding: Temporal Scalability 7

Scalable Coding: Spatial Scalability 8

Scalable Coding: SNR (Quality) Scalability 9

Summary of Scalable Video Coding 10

11 Standards

What do the Standards Specify? 12

What do the Standards Specify? 13

Current Image and Video Compression Standards 14

Comparing Current Video Compression Standards 15

16 MPEG-1 and MPEG-2

Example Use of I-,P-,B-frames: MPEG Group of Pictures (GOP) 17

MPEG Group of Pictures (GOP) Structure 18

19 MPEG Structure

20 MPEG-2 Profiles and Levels

21 Goals of MPEG-4

Comparing MPEG-1/2 and H.261/3 with MPEG-4 22

MPEG-4 A Case-study of Object-based Video Coding 23

Comments on Object-based Processing 24

Comments on Object-based Processing 25

26 Different Parts of MPEG-4

27 Scene Description

Scene Description • Example of MPEG-4 Scene [MPEG Committee] 28

29 Scene Description

Example MPEG-4 Decoding Process 30

Object-based Processing in the Compressed Domain 31

32 MPEG-4 Natural Video

MPEG-4 Coding of Natural Video 33

MPEG-4 Natural Video Coding 34

Coding of Arbitrarily Shaped Video Objects � Different aspects of coding arbitrarily shaped video objects: – Coding of texture (amplitude) information – MC-prediction – I, P, B coding of objects – Coding of shape information � Goal: brief, conceptual overview � Key points to take away: 1. Different attributes to code for arbitrarily shaped video objects → Texture, motion, & shape information 2. MPEG-4 extends block-based coding to code arbitrarily shaped objects (Not an elegant solution, but it works) 35

Example of Arbitrarily Shaped Object 36

37 Comments on Segmentation

Coding the Texture of an Arbitrarily Shaped Object 38

MC-Prediction for Texture Coding of Arbitrarily Shaped Object 39

MC-Prediction for Video Object Planes: I, P, and B VOP’s 40

41 Binary Shape Coding

Binary Shape Coding: Block-based Shape Coding 42

Binary Shape Coding: Block-based CAE (cont.) 43

Sprite Coding (Background Prediction) 44

45 Sprite Coding Example

Related MPEG Standards (non-compression) 46

MPEG Links � http://www.mpeg.org � http://www.chiariglione.org/mpeg/ � http://www.m4if.com/ 47