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MPEG-4

MPEG-4. Introduction MPEG4 Video MPEG4 Tools MPEG4 Video Object MPEG4 Video Profile MPEG4 Simple Profile MPEG4 Advanced Simple Prolile. Introduction. ITU/ISO 1994 年制定， 1998 年成为标准，对应的标准号为 14496 目的 是要在异构网络环境下能够高度可靠地工作，并且具有很强的交互功能 。

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MPEG-4

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  1. MPEG-4 • Introduction • MPEG4 Video • MPEG4 Tools • MPEG4 Video Object • MPEG4 Video Profile • MPEG4 Simple Profile • MPEG4 Advanced Simple Prolile

  2. Introduction • ITU/ISO 1994年制定，1998年成为标准，对应的标准号为14496 • 目的是要在异构网络环境下能够高度可靠地工作，并且具有很强的交互功能。 • 制定了一个称为传输多媒体集成框架(Delivery Multimedia Integration Framework，DMIF)的会话协议，它用来管理多媒体数据流 ，DMIF覆盖了三种主要技术： • 广播技术 • 交互网络技术 • 光盘技术 • 相对其他编码标准，引入了对象的概念，以对象为编码单位，有自然数据扩展到合成数据，对象可以是自然的，也可以计算机合成的，可以是图像，也可以是声音，可以是一段文字，总之对象是一个抽象的概念，对向的操作引入了组合，合成和编排等概念

  3. MPEG－4标准的16个部分 Part 1, Systems: Scene description, multiplexing of audio, video and related information,synchronisation, buffer management, intellectual property management. Part 2, Visual: Coding of ‘natural’ and ‘synthetic’ visual objects (see Chapter 5). Part 3, Audio: Coding of natural and synthetic audio objects. Part 4, Conformance Testing: Conformance conditions, test procedures, test bitstreams. Part 5, Reference Software: Publicly-available software that implements most tools in the standard. Part 6, Delivery Multimedia Integration Framework:Asession protocol for multimedia streaming. Part 7, Optimised Visual Reference Software: Optimised software implementation of selected Visual coding tools. This Part is a Technical Report (and not an International Standard).

  4. MPEG－4标准的16个部分 Part 8, Carriage of MPEG-4 over IP: Specifies the mechanism for carrying MPEG-4 coded data over Internet Protocol (IP) networks. Part 9, Reference Hardware Description: VHDL descriptions of MPEG-4 coding tools (suitable for implementation in ICs). This Part is a Technical Report and is still under development. Part 10, Advanced Video Coding: Efficient coding of natural video (see Chapter 6). This Part is under development and due to become an International Standard in 2003. Part 11, Scene Description and Application Engine. Part 12, ISO Base Media File Format. Part 13, Intellectual Property Management and Protection Extensions. Part 14, MPEG-4 File Format Part 15, AVC File Format Part 16, Animation Framework Extension.

  5. MPEG－4视频 和MPEG-1/-2 Video不同， MPEG4视频形状可以是矩形的也可以被分割成许多任意形状的图像区，每个区都有可能覆盖描述场景中感兴趣的物理对象或者内容，这种区被定义为图像对象区VOP。 VO的属性：形状，纹理，移动

  6. MPEG4中的Tools • A tool is a subset of coding functions to support a specific feature • 一些编码技术，比如DCT，帧内编码，前向预测，双向预测….

  7. MPEG4中的视频对象 A entity that a user is allowed to access (seek, browse) and manipulate (cut and paste) A video object (VO) is an area of the video scene that may occupy an arbitrarily-shaped region and may exist for an arbitrary length of time.

  8. Rectangular Video Object

  9. Arbitrary shape Video Object

  10. Video Scene

  11. Profiles • A profile is a set of object types that a CODEC isexpected to be capable of handling. • Profile中明确了使用那些技术对那些对象进行编码

  12. Profile of nature video

  13. Profile of synthetic or hybrid video

  14. Visual Profile and Visual Object Type

  15. Levels

  16. Simple Profile • Define Subset Tools for Simple Video Objects • I-VOP (Intra-coded rectangular VOP, progressive video format); • P-VOP (Inter-coded rectangular VOP, progressive video format); • short header (mode for compatibility with H.263 CODECs); • compression efficiency tools (four motion vectors per macroblock, unrestricted motion vectors, Intra prediction); • transmission efficiency tools (video packets, Data Partitioning, Reversible Variable Length Codes).

  17. Advanced Simple Profile • An Advanced Simple ProfileCODECmust be capable of decoding Simple objects as well as Advanced Simple objects which may use the following tools in addition to the Simple Profile tools • B-VOP (bidirectionally predicted Inter-coded VOP); • quarter-pixel motion compensation; • global motion compensation; • alternate quantiser; • interlace (tools for coding interlaced video sequences).

  18. Visual Object Types Visual Tools Advanced Simple simple I-VOP X X P-VOP X X B-VOP X DC Prediction X X AC Prediction X X 4-MV, Unrestricted MV X X Slice Resynchronization X X Data Partitioning X X Reversible VLC X X Short Header X X Method 1/Method 2 Quantization X Interlace X Global Motion Compensation X Quarter-pel Motion Compensation X Tools of SP and ASP

  19. 图像的合成

  20. Video Object

  21. MPEG4编码框图

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