Multimedia for our time(For Dummies)

ISO/IEC 14496

Visa

Hyoungjune Yi

Preface

Environment– TV System– Wireless

IS-95, CDMA200, IMT2000

Compression

Standard

TV System

PAL – Phase Alternation Line rate (Main Europe , inc. Finland) NTSC – National Television Systems Committee (USA & Canada) SECAM – Sequential Coleur Avec Memoire (France, former Soviet)

NTSC 525 484 242 4/3 427 29.94 PAL 625 575 290 4/3 425 25 SECAM 625 575 290 4/3 465 25

IS-95A, IS-95B, IS-95C, IMT 2000

Why not TDMA? Bandwidth matters 9.6K, 14.4K(IS-95A), 56K, 64K (IS-95B) bps IS-95A,B – Circuit switching CDMA2000 1X (IS-95C) , W-CDMA

– 144 ~ 384Kbps IMT2000 (International Mobile Telecommunication 2000)

– 2 ~ 5 Mbps Bandwidth

Compression

Lossy : Reconstructable Lossless

Symbol level– Huffman

Block level– RLE, Arithmetic Encoding, LZ

Compression

Idea– Reduce spacial / temporal redundancies

Pre-knowledge– FT, DCT, Haar’s, Gibbs phenomenon, Max-Lloyd

Quantizer, Vector quantization– Subband coding and why?, LPF, HPF

Standard

Why?– Compatibility – Real player, WMP, Quick-time– Production, cost reduction

Standard kills research, right?– Profile level– Decoder only (MPEG2, MPEG4)– Very flexible to encoder side

ISO/IEC IS 10918

Lossless 8 X 8 block Mean normalization DCT on each block Quantization (4 quantization matrices per img) Entropy coding of DC component (Zig-zag) Entropy coding of AC component

H.261, H.263 and MPEG

H.261 – CCITT, ISDN H.263 – Visual telephony ISO/IEC 11172 – CD, 1.5 Mbit/sec ISO/IEC 13818 – DVD, over 10Mbit/sec MPEG3 – 50 ~ 100 Mbit/sec ISO/IEC JTC/SC29/WG11 N2323 – Variable bitrate,

9.6K ~ 100Mbps ISO/MPEG N2728, 2729 – Describing multimedia

material MPEG11

Normalized Bit rate

(C X R) / ( HX V X F)

Group of pictures (GOP)

GOP– Intra (I) frame– Predicted(P) frame– Bidirectional (B) frame

I and P– Anchor picture– Stored in memory– Basis for prediction of B picture

GOP in ISO/IEC 11172

Coding order != Display order Closed vs. Open

Refer handouts for more on MPEG1 and MPEG2

Motion Estimation (ISO/IEC 11172 )

Illumination part only 16 X 16 macro block P frame

– P predicted from R (P or I)– For each MB in P, find the best match in R– Record motion– Compensate MB – MB’– No standard for matching algorithm, decision algo.

Motion Estimation(ISO/IEC 11172 )

B frame– B predicted from two Rs– Same as P

Rate Control (ISO/IEC 13818 )

See whiteboard

Constant quality, variable bit rate (VBR)

Variable quality, constant bit rate(CBR)

CBR rate control

MPEG2 scalability modes

Spatial– Base layer– Enhanced Layer– Wavelet?

Temporal

Adjustable

ISO/IEC 14496

Provides very low Bitrate, Error resilience Can be carried in MPEG-2 system layer Entity(Text, graphics, …) can be overlaid on

MPEG-2 Video for enhancement content Synthetic audio and video(2, 3D graphics) Support interlaced/progressive scanning

ISO/IEC 14496

Goodbye BLOCK OBJECT BASED REPRESENTATION Object description is required Shape coding Content layers are selected at MPEG4

Terminal

ISO/IEC 14496

Client can manipulate the contents at his terminal - INTERACTIVITY

Server requires back channel Compression rate

– Vs. MPEG2– Discuss how can we increase the compression ratio

Object in ISO/IEC 14496

Scene Graph (Video, audio, text and graphic) Transformation and properties are specified Visual object and audial(acoustical) object Compound object can be generated Synthetic and natural object System supports multiplexing and

synchronization between media objects

MPEG4 Video coding scheme

Shape coding and motion compensation Shape adapted DCT Local block based vs. global (Sprites) Motion

compensation First compute static sprite Transmit 8 or 6 global motion parameters Moving foreground is transmitted separately

ISO/MPEG N2728

Multimedia Contents Description Interface Meta data of multimedia data Personal preference, permission Applications

– Education , Journalism, Gallery– Entertainment(Karaoke)– Investigation, Surveillance, recognition, GIS, remote sensing– Biomedical, shopping, dating service– Video to text

MPEG11

I GOT YOU !!!

MPEG 21

Description language(MPEG7) & Not for contents but for Media