西安电子科技大学多媒体研究所：《多媒体数据处理》第十章 MPEG4标准介绍（崔江涛）

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MPEG4标准介绍

MPEG4的引入 ■因特网的多媒体应用;多媒体移动通信;多媒体 创作工具;多媒体数据库;交互式视频购物和视 频游戏;以及远程监控和医疗等。 而MPEG-1和MPEG-2采用的基于“帧和基于“块 的压缩算法,不能支持表征图像内容的数据结构。 而这些又正是许多交互式应用所必需的。 当"码率很低时"会产生严重的"方块效应"和"动作 失真",而"低码率"又是多媒体移动通信所必需的 因此,既然预见到了3C融合所出现的需求,就必 须努力克服MPEG-2的不足

◼ 因特网的多媒体应用；多媒体移动通信；多媒体 创作工具；多媒体数据库；交互式视频购物和视 频游戏；以及远程监控和医疗等。 ◼ 而MPEG-1和MPEG-2采用的基于“帧”和基于“块” 的压缩算法，不能支持表征图像内容的数据结构。 而这些又正是许多交互式应用所必需的。 ◼ 当"码率很低时"会产生严重的"方块效应"和"动作 失真"，而"低码率"又是多媒体移动通信所必需的。 因此，既然预见到了3C融合所出现的需求，就必 须努力克服MPEG-2的不足。 MPEG4的引入

MPEG4目标 专门用于64kbps以下的甚低速率下的音 视频编码 不仅适应与移动通信和个人通信业务 而且也使用于固定功用通信网和电视电 话 使用于窄带多媒体通信等广泛的应用; 实现基于内容的压缩编码,具有良好的 兼容、伸缩性、可靠性

MPEG4目标 ◼ 专门用于64kbps以下的甚低速率下的音 视频编码； ◼ 不仅适应与移动通信和个人通信业务， 而且也使用于固定功用通信网和电视电 话； ◼ 使用于窄带多媒体通信等广泛的应用； ◼ 实现基于内容的压缩编码，具有良好的 兼容、伸缩性、可靠性

MPEG4 Coding of audio-visual objects, from 1994 ■Part1 Systems Part 10 Advanced Part2Ⅴ isual Video coding ■Part3 audio Part 11 Scene Description Part 4 Conformance testing and Application Engine Part 5 Reference Software Part 12 ISo Base Media a Part 6 Delivery Multimedia File format Integration Framework Part 13 IPMP Extensions Part7 Optimised software for (Intellectual Property MPEG-4 tools Management and Protection Part8 4 on IP framework Part 14 MP4 File format Part 15 AVC File format Part 9 Reference Hardware Description Part 16 Animation Framework eXtension(AFX

MPEG4 Coding of audio-visual objects，from 1994 ◼ Part 1 Systems ◼ Part 2 Visual ◼ Part 3 Audio ◼ Part 4 Conformance testing ◼ Part 5 Reference Software ◼ Part 6 Delivery Multimedia Integration Framework ◼ Part 7 Optimised software for MPEG-4 tools ◼ Part 8 4 on IP framework ◼ Part 9 Reference Hardware Description ◼ Part 10 Advanced Video Coding ◼ Part 11 Scene Description and Application Engine ◼ Part 12 ISO Base Media File Format ◼ Part 13 IPMP Extensions (Intellectual Property Management and Protection ) ◼ Part 14 MP4 File Format ◼ Part 15 AVC File Format ◼ Part 16 Animation Framework eXtension (AFX)

New Project (MPEG a 3DAV: coding of audio and video information from a 3D space 三维空间内音视频信息编码 Scalable video Coding: coding of video with high scalability features and high compression 可伸缩性视频编码

New Project (MPEG) ◼ 3DAV: coding of audio and video information from a 3D space 三维空间内音视频信息编码 ◼ Scalable Video Coding: coding of video with high scalability features and high compression 可伸缩性视频编码

Over view(编码) standardized ways to support ■ Coding(编码) representing units of audio, visual, audiovisual content Composition(合成) I describing how these objects are composed together to produce compound media objects Multiplex(多路复用和合成) a multiplex and synchronize data associated with media objects ■ Interaction(交互性) a interacting with user

OverView（编码） ◼ standardized ways to support: ◼ Coding（编码） ◼ representing units of audio, visual, audiovisual content ◼ Composition（合成） ◼ describing how these objects are composed together to produce compound media objects ◼ Multiplex（多路复用和合成） ◼ multiplex and synchronize data associated with media objects ◼ Interaction（交互性） ◼ interacting with user

System overview(解码) a number of decoders for each type of media(解码) a a composition process which puts the decoded parts together(分量合成) composition ideas are similar to VRML(合成方法) a scene graph of objects composition information is defined in the links hierarchical structure, not necessarily static composition stream has extra information for mp4 a spatial relationships a temporal relationships

System overview（解码） ◼ a number of decoders for each type of media（解码） ◼ a composition process which puts the decoded parts together（分量合成） ◼ composition ideas are similar to VRML（合成方法） ◼ 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

voice multiplexed sprite presentation downstream control/ data 2D background multiplexed SCere controddata coordinate System X userevents compositor projector hypothetical viewer C display userinput

scene person 2D background furniture audiovisual presentation voice sprite globe desk

Decompression Composition and Rendering Primitive AV Objects Scene Description (Script or Classes Hierarchical, Interactive Audiovisual Scene Composition Infomation