1 Mpeg-4 Overview Gerhard Roth

2 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

3 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

4 Receiver/Decoder architecture

5 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)

6 Multiplex/synchronization layer

7 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

8 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

9 Video

10 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

11 Face definition parameters a number of feature points on a neutral face

12 Face animation parameters a number of face animation points

13 2d mesh decoding mesh vertices points can move in 2d

14 2d mesh of fish

15 2d mesh augmentation of fish –the letters are synthetically overlaid on the video object and move in synchronization with it

16 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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