mpeg-4 overview
DESCRIPTION
Mpeg-4 Overview. Gerhard Roth. Overview. Much more general than all previous mpegs standard finished in the last two years standardized ways to support: coding representing units of audio, visual, audiovisual content composition - PowerPoint PPT PresentationTRANSCRIPT
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Mpeg-4 Overview
Gerhard Roth
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Overview
• Much more general than all previous mpegs– standard finished in the last two years
• standardized ways to support:– coding
• representing units of audio, visual, audiovisual content
– composition• describing how these objects are composed together to produce
compound media objects
– multiplex• multiplex and synchronize data associated with media objects
– interaction• interacting with user
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System overview
• a number of decoders for each type of media• a composition process which puts the decoded
parts together• composition ideas are similar to VRML
– scene graph of objects
– composition information is defined in the links
– hierarchical structure, not necessarily static
– composition stream has extra information for mp4• spatial relationships
• temporal relationships
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Receiver/Decoder architecture
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Multiplex synchronization
• timing and synchronization of media• three layers
– specific information for timing and synchronization of the coded media (synchronization layer)
– multiplex streams with different characteristics (flexible multiplex layer)
– add the multiplex stream to a particular network (transport multiplex layer)
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Multiplex/synchronization layer
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Intellectual property protection
• ipmp = intellectual property management and protection
• interface that permits mp4 to host one or more ipmp systems
• ipmp framework has– normative interface that permits mpeg-4 terminal to
host one or more IPMP systems
– non normative component that provides intellectual property management
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Video
• Tools for efficient compression of • images, video, 2d textures
• time varying geometry (animated meshes)
• efficient random access
• extended manipulation functionality
• content based coding and scalability
• error robustness and resilience
• based on video object– entity in scene that user can manipulate and access
• video object planes– instances of video objects at a given time
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Video
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Media integration of text and graphics
• 3d graphics– like VRML including script nodes
• face animation– face definition parameters (FDPs)
– face animation parameters (FAPs)
• 2d mesh encoding– dynamic mesh, a temporal sequence of 2d triangular
meshes
• texture coding via wavelets
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Face definition parameters
• a number of feature points on a neutral face
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Face animation parameters
• a number of face • animation points
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2d mesh decoding
• mesh vertices points can move in 2d
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2d mesh of fish
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2d mesh augmentation of fish– the letters are synthetically overlaid on the video object
and move in synchronization with it
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Conclusion
• a superset of old VRML and Mpeg-1 and Mpeg-2• very general, many concepts
– can mix and match many different compression algorithms for different objects
– handles everything (audio, video, 2d-3d, faces, mesh…)
– is a first attempt at integrating 2d and 3d worlds
• DivX is a software application that uses the MPEG-4 standard to compress digital video
• DivX is done with the open source community– much better compression than ordinary DVDs
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URLs