Lecture-20 - Lecture-20 MPEG-4 1 MPEG-4 MPEG-4 is the...

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1 Lecture-20 MPEG-4
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2 MPEG-4 • MPEG-4 is the international standard for true multimedia coding. • MPEG-4 provides very low bitrate & error resilience for Internet and wireless. • MPEG-4 can be carried in MPEG-2 systems layer. MPEG-4 • 3-D facial animation • Wavelet texture coding • Mesh coding with texture mapping • Media integration of text and graphics • Text to speech synthesis
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3 Applications of MPEG-4 • Multimedia broadcasting and presentations • Virtual talking humans • Advanced interpersonal communication systems • Games • Storytelling • Language teaching • Speech rehabilitation • Teleshopping • Telelearning MPEG-4 • Real audio and video objects • Synthetic audio and video • Integration of Synthetic & Natural contents (Synthetic & Natural Hybrid Coding)
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4 MPEG-4 • Traditional video coding is block-based. • MPEG-4 provides object-based representation for better compression and functionalities. • Objects are rendered after decoding object descriptions. • Display of content layers can be selected at MPEG-4 terminal. MPEG-4 • User can search or store objects for later use. • Content does not depend on the display resolution. • Network providers can re-purpose content for different networks and users.
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5 • Authors – reusability – flexibility – content owner rights • Network providers • End users Media Objects • Primitive Media Objects • Compound Media Objects • Examples – Still Images (e.g. fixed background) – Video objects (e.g., a talking person-without background) – Audio objects (e.g., the voice associated with that person) – etc
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6 MPEG-4 Versions MPEG-4 functioanlities 5 kbps 64 kbps 4 Mbps VLB Core 1. Low resolution CIF (360X288) 2. Low frame rate 15fps 3. High coding efficiency 4. Low complexity, low error 5. Random access 6. Fast forward/reverse High Bitrate 1. Higher resolution 2. Higher frame rate 3. Interlaced video Content-based functionalities 1. Interactivity 2. Flexible representation and Manipulation in the compressed Domain 3. Hybrid coding
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7 User Interactions • Client Side – content manipulation done at client terminal • changing position of an object • making it visible or invisible • changing the font size of text • Server Side – requires back channel • Efficient representation of visual objects of arbitrary shape to support content-based functionalities • Supports most functionalities of MPEG-1 and MPEG-2 – rectangular sized images – several input formats – frame rates – bit rates – spatial, temporal and quality scalability
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8 Object Composition • Objects are organized in a scene graph. • VRML based binary format BIF is used to specify scene graph. • 2-D and 3-D objects, transforms and
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This note was uploaded on 06/12/2011 for the course CAP 6411 taught by Professor Shah during the Spring '09 term at University of Central Florida.

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Lecture-20 - Lecture-20 MPEG-4 1 MPEG-4 MPEG-4 is the...

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