INTRODUCTION 1) Background a) Combine text + graphics b) Visual + audio c) Catalog and index image + efficient storage and delivery 2) 4 Difficulties d) Data type e) Data manipulation f) Data storage g) Data delivery 3) Importance h) Store Image (eg:museum) i) Search and manipulate content 4) Types j) Images k) Audio l) Video m) Document n) Handwritten 5) Application o) GIS,CAD,Face-retrieval,doc imaging, medical db, web 6) Characteristic p) Treat mdb same way as data based 7) 4 Challenges q) Size r) Time s) Semantic Nature of Multimedia ) Operation of individual media 8) 5 Features u) Support diff.
multimedia data type v) Handle large no. multimedia obj. w) Hierarchical storage structure & archiving data x) Information-retrieval y) Database capabilities MULTIMEDIA DATA 1. Multimedia data size [Size of media data makes storage, processing, transmission and reception of the data very costly] a. Multimedia data acquisition * Data capture: photo/audio/video * Sampling: convert analog to digital * 8bits = 256 colors * 24bits = 16 million colors b.
Dealing with Media Object Size * 2 approaches : store references/reduce size media * SQL:1999 2 data type BLOB & CLOB Lack in (PK, FK ,equality test) * Oracle9i: support 2 LOB #internal LOB: BLOB & CLOB #external LOB: BFILE * IBM DB2: BLOB,CLOB,DBLOB(china) c. Reducing Media Object’s Size * Compression algorithm *remove duplicate information *abbreviating information * Objective *Reduce bandwidth/storage *Decode signal close to original *Robustness,scalability,extensibility * 2 stages: *Predict-estimate redundant & select algorithm Transform-Compress & Decompress * 2 form of compression *Lossless-lose none,2:1,3:1 *Lossy-lose some,10:1,80:1 * Two ways *Run-length encoding *Huffman coding * 2. Real-Time Nature of Multimedia Data d. Segmentation: subdividing video obj e.
Manual segmentation costly so focus on automatic segmentation 3. Semantic Nature of Multimedia Data f. Semantic: metadata describe multimedia obj. g. Refer as: text desc/characteristic of metadata(texture of image,frequencies of audios,font size for text)
