T.Sharon-A.Frank 1 Multimedia Size of Data Frame
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Transcript of T.Sharon-A.Frank 1 Multimedia Size of Data Frame
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- T.Sharon-A.Frank 1 Multimedia Size of Data Frame
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- 2 T.Sharon-A.Frank Major Issues 1. Size of Data Frame 2. Need High Bandwidth 3. Digital vs. Analog Representation 4. Multi-Modality Integration/Blending 5. Soft Real-Time Constraints 6. Need Group Communication 7. Need Synchronization 8. Need for Standards
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- 3 T.Sharon-A.Frank 1. Size of Data Frame
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- 4 T.Sharon-A.Frank Storage Requirements 580 MB 1 GB 1 GB 500 MB 100 MB 100 MB 6.4 MB 10 MB 1 MB 1 MB 500 pages 100 fax line 100 color 10 min of 10 min of 1 hour of of text images images animation video video (uncompr.) (compr. 15:1) ( compr. 15:1) (compr. 30:1) ( compr. 200:1)
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- 5 T.Sharon-A.Frank Use Compression Use Smaller Frame Size Solutions
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- 6 T.Sharon-A.Frank (Smaller) Frame Sizes 640x480352x288174x144 PAL CIF QCIF (Q)CIF (Quarter) Common Interchange Format
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- 7 T.Sharon-A.Frank What is Compression? Process of reducing the amount of data required to represent a given quantity of information. Same amount of information represented using fewer bits relies on the notion of data redundancy. Sometimes called packing, coding, encoding or zipping.
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- 8 T.Sharon-A.Frank Compression Necessity (1) Network 2. Bus 1. Storage 3. Communications
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- 9 T.Sharon-A.Frank Compression Necessity (2) 1.Storage data is compressed before being stored, decompressed before being retrieved. 2.Bus compressed data transfer requires reduced bandwidth. 3.Communications sender compresses data before sending it over line, receiver decompresses it after receiving it.
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- 10 T.Sharon-A.Frank Compression Characteristics (A)Symmetrical Compression Lossless/Lossy Compression Spatial/Temporal Compression
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- 11 T.Sharon-A.Frank Types of Compression Entropy encoding lossless. Data considered a simple digital sequence and semantics of data are ignored. Source encoding lossy. Takes semantics of data into account. Amount of compression depends on data contents. Hybrid encoding combination of entropy and source. Most multimedia systems use these.
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- 12 T.Sharon-A.Frank Compression Schemes (1) Lossless Compression Method files are packed and unpacked without losing original data. Run Length Encoding (RLE): Algorithm redundant information replaced with run length code. Symmetrical Lossy Compression Method some loss of original data. Joint Photographic Expert Group (JPEG): Uses DCT algorithm, works best on images without sharp edges or detail. Spatial Compression redundancies in images are compressed.
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- 13 T.Sharon-A.Frank Compression Schemes (2) Asymmetrical Lossy Compression some loss of original data. Motion Picture Expert Group (MPEG): applies predictive inter- frame coding techniques. Combination of Spatial and Temporal compression checks for redundancies within frame and from frame to frame.
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- 14 T.Sharon-A.Frank Compression Standards (1) Joint Photographic Experts Group (ISO) International Standard for Continuous-Tone Still Image Compression (Color Pictures, Slides) Recommended in 1991 JPEG P*64 Multiple of 64 Kbps Coding (CCITT) International Standard for Video Telephony, Conferencing and Collaboration Recommended in Q4 1990
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- 15 T.Sharon-A.Frank Compression Standards (2) Motion Pictures Experts Group (ISO) International Standard for Compression of Addressable Video Recommended in Q2 1992 MPEG-1 MPEG-2 International Standard for Digital Broadcast Quality TV Recommended in Q4 1994 International Standard for Narrowband Digital Broadcast of Media Objects Recommended in Q4 1998 MPEG-4
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- 16 T.Sharon-A.Frank Compression Standards (3) High Definition Television (FCC) Next Generation Standard for High Resolution Broadcast TV Recommended in Q4 1995 (ATSC DTV) HDTV
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- 17 T.Sharon-A.Frank Video Coding Techniques MPEG1: standard for storage and retrieval of moving pictures and audio (VCR quality) on storage media (CD-ROM, WORM). MPEG2: standard for digital TV quality. MPEG4, H.261: standard for multimedia applications at very low bit-rate. MPEG7: multimedia content representation standard for information search.
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- 18 T.Sharon-A.Frank Emerging Market Segments (1)
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- 19 T.Sharon-A.Frank Emerging Market Segments (2)