Media - Video Coding: Standards

Transcription

1 Media - Video Coding 1. Scenarios for Multimedia Applications - Motivation - Requirements 15 Min 2. Principles for Media Coding 75 Min Redundancy - Irrelevancy 10 Min Quantization as most important principle of Irrelevancy Reduction 10 Min Entropy Coding (Run length, Hufman) as Redundancy Reduction 10 Min Predictive Coding and DPCM based on decorrelation of signals 10 Min Intraframe Coding (Motion Compensation) for temporal prediction 10 Min Transform Coding (DCT) for decorrelation of signals 10 Min Hybrid Coding the basic coding principle for all standards 15 Min 3. Standards 120 Min Overview, importance of standards 15 Min ITU - H H.26L, principles, demos (video quality at various rates) 15 Min MPEG-2; MPEG-4, principles, demos (Functionality of MPEG-4) 30 Min MPEG-7: principles, applications, demos 30 Min JPEG-2000: Principles,demos (Functionality of JPEG-2000) 30 Min 1 Dr. Eckart Hundt; Siemens AG, CT IC 2; D München; Tel.: ; eckart.hundt@mchp.siemens.de

2 JPEG 2000 Features Low bit rate compression: Compression is superior to JPEG especially at low bit rates Continuous tone and bi-level compression:various dynamic range for each colour component and provide lossless colour transformation Lossless and lossy Compression: performed in one algorithm and provided in progressive decoding Region of Interest: Certain regions (static and dynamic)can be coded with better quality than the rest of the image Progressive transmission by pixel accuracy and resolution: Reconstruction of images with different resolutions and pixel accuracy Scalability:Images are simultaneously available for decoding at a variety of resolutions and qualities Random codestream access and processing: Composition of image data from different layers and regions; Compression of total image with different parameters for various image elements; Sorting of data stream according to predefinable significance criteria; Control of image quality during decompression 2 Error resilience: Datapartioning, Resynchronisation, Error detection and concealment and QoS transmission based on priority

3 Rate-Distortion Comparison JPEG2000 1: 96 JPEG 1: 96 3

4 Comparison of compression artefacts JPEG2000 JPEG 1:24 PSNR = 25,03 PSNR = 23,83 1:96 4 PSNR = 20,45 PSNR = 13,12

5 JPEG 200 Coding Scheme The original image is divided in rectangular, non overlapping blocks (tiles) Wavelet transform,quantisation and entropy coding areperformed independently on the different tiles (Memora reduction and region of interest features) Tile components are decomposed by wavelet transform with user defined filter banks into subbands representing the horizontal and vertical spatial frequencies (default for irreversible Daubechies 9-tap/7-tap filter) Each subband is divided into rectangular code-blocks and coded independently by arithmetic coding at a bit plane levels (special code block scan pattern, rate distortion optimisation for bit allocation 5

6 Forward Discrete Wavelet Transform (FDWT) Each individual tile of each component is processed by a wavelet transform Reversible and irreversible transforms possible Coefficients provide local ferquency information User defined filter banks possible (default Daubechies 9-/7-tap for irreversible) Convolution based and lifting based filtering possible The resolution depth can be chosen (default =5) Depth 5 Depth 1 6

7 Sub-Bands for Wavelet Transform For each resolution layer 3 subbands are generated 1LL Highpass Vertical Filter Lowpass 2H 2L Highpass Horizontal Filter Lowpass Highpass Horizontal Filter Lowpass 2HH 2HL 2LH 72LL

8 Components and Tiles Images are partioned into rectangular non-overlapping tiles Images are composed from several components Regions Of Interest can be defined Liebe Grüße von Deinem Enkel Region Of Interest Text-Component 4x4-tiles Blue Component Green Component Red Component 8

9 ROI for GSM-Transmission at 9.6 kbit/s Progressive Download (CIF 352 x 288) 0.5 s 2 s 3 s Progressive Download with Region of Interest (CIF 352 x 288) s 0.5 s 1 s

10 Markets and Applications Region of Interest Coding E-Commerce Quality on Demand Mobile Internet Medical Error Resilience Digital Photography Progressive10 Transmission

11 Status of JPEG 2000 JPEG2000 Part Part I I Committee Draft Draft Version since since December available JPEG2000 Part Part II II Working Draft Draft Version Pre-Release A since since January available Verification Software VM6.1 VM6.1 since since February available Definition of of Motion-JEPEG2000 starts starts JPEG2000 Part Part I I International Standard November JPEG2000 Part Part II II International Standar Juli Juli

12 Literature Standards ITU-T Rec. T.81 (1992 E), identisch mit ISO/IEC : 1993(E) "Information Technology - Digital Compression and Coding of Continuous-Tone Still Images - Requirements and Guidelines" ITU-T Rec. T.84 (1994 E), identisch mit ISO/IEC : 1994(E) Working Draft: "Information Technology - Digital Compression and Coding of Continuous Tone Still Images: Extensions" G. K. Wallace: "The JPEG Still Picture Compression Standard", Communications of the ACM, April 1991, Vol.34, No.4, S R. Steinmetz: "Data compression in multimedia computing - standards and systems", Multimedia Systems (1994) 1: S Gregory K. Wallace, "the JPEG Still Picture Compression Standard", IEEE Trans. Consumer Electronics, Februar 1992 A. Knoll, " Der MPEG-2-Standard zur digitalen Codierung von Fernsehsignalen", Der Fermeldeingenieur July 1992 Teicher, D; "Der MPEG 2 Standard"; FKTG 48. Jahrgang Nr ; p. 155 und p. 227 Herpel, C.; " Der MPEG 2 Standard", Der MPEG 2 Standard FKTG 48. Jahrgang Nr , p. 311 Riemann, U.; " Der MPEG 2 Standard: Multiplex Spezifikation", FKTG 48. Jahrgang nr. 9/ 1994, p.460 A. N. Skodras, C.A. Christopoulos, T. Ebrahimi: JPEG-200 The Upcoming Still Image Compression Standard Proc. 11th Port. Conf. Oattern Rec. May 2000, p.359 K. Rao and J. Hwang, Techniques & Standards for Image, Video and Audio Coding, Prentice Hall PTR, Upper Saddle River, New Jersey, 1996 Generic Coding of Moving Pictures and Associated Audio: Systems, ISO/IEC JTC1/SC29/WG11/N0801, April 1995 Overview of the MPEG-4 Standard, ISO/IEC JTC1/SC29/WG11, July