MPEG4标准介绍
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 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)
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
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 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
Receiver/Decoder architecture
Multiplex synchronization
timing and synchronization of media（同步）
three layers（三层）
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)
三层示意图
MPEG4示例
...
Decoding
Audiovisual Interactive
Scene
Composition and
RenderingPrimitive
AV Objects
Scene Description
Information
...
Elementary
Streams
FlexMuxN
e
t
w
o
r
k
TransMux
...
Ex,MPEG-2
Transport
Object Descriptor
Display and
Local User
Interaction
DMIF - Application
Interface (DAI)
多媒体传输集成框架
MPEG4示例 2（交互性）
N
e
t
w
o
r
k
User to User Interaction
...
Elementary
Streams
FlexMuxTransMux
...
Return Channel
Encoding
DMIF - Application Interface (DAI)
Structure of the tools for representing natural
video （自然景象）
A basic classification of
the bit rates and
functionalities currently
provided by the MPEG-
4 Visual standard for
natural images
(VLBV,Very Low Bit-rate Video)
provides algorithms and tools for
applications operating at bit-rates
typically between 5...64 kbits/s
Video
Tools for efficient compression of
images,video,2d textures（二维纹理）
time varying geometry (animated meshes)（网格动画）
efficient random access（随机 存取）
extended manipulation functionality（扩展操控功能）
content based coding and scalability（内容编码和可伸缩性）
error robustness and resilience（鲁棒性和错误校验）
based on video object（视频对象）
entity in scene that user can manipulate and access
video object planes（视频对象区）
instances of video objects at a given time
Example of Sprite Coding of Video
Sequence
The MPEG-4 Video Image Coding
Scheme? An important
advantage of the
content-based
coding approach
MPEG-4 is that the
compression
efficiency can be
significantly
improved for some
video sequences by
using appropriate
and dedicated
object-based
motion
prediction,tools” for
each object in a
scene
Media integration of text and
graphics（文本和图形集成）
3d graphics（三维图形）
like VRML including script nodes
face animation（脸部动画）
face definition parameters (FDPs)
face animation parameters (FAPs)
2d mesh encoding（二维网格）
dynamic mesh,a temporal sequence of 2d triangular
meshes
texture coding via wavelets（小波纹理编码）
Face definition parameters
a number of feature points on a neutral face
face
animation
parameters
2d mesh decoding
mesh vertices points can move in 2d
2d mesh of fish
2d mesh augmentation of fish
the letters are synthetically overlaid on the video object and
move in synchronization with it
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
URLs
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 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)
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
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 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
Receiver/Decoder architecture
Multiplex synchronization
timing and synchronization of media（同步）
three layers（三层）
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)
三层示意图
MPEG4示例
...
Decoding
Audiovisual Interactive
Scene
Composition and
RenderingPrimitive
AV Objects
Scene Description
Information
...
Elementary
Streams
FlexMuxN
e
t
w
o
r
k
TransMux
...
Ex,MPEG-2
Transport
Object Descriptor
Display and
Local User
Interaction
DMIF - Application
Interface (DAI)
多媒体传输集成框架
MPEG4示例 2（交互性）
N
e
t
w
o
r
k
User to User Interaction
...
Elementary
Streams
FlexMuxTransMux
...
Return Channel
Encoding
DMIF - Application Interface (DAI)
Structure of the tools for representing natural
video （自然景象）
A basic classification of
the bit rates and
functionalities currently
provided by the MPEG-
4 Visual standard for
natural images
(VLBV,Very Low Bit-rate Video)
provides algorithms and tools for
applications operating at bit-rates
typically between 5...64 kbits/s
Video
Tools for efficient compression of
images,video,2d textures（二维纹理）
time varying geometry (animated meshes)（网格动画）
efficient random access（随机 存取）
extended manipulation functionality（扩展操控功能）
content based coding and scalability（内容编码和可伸缩性）
error robustness and resilience（鲁棒性和错误校验）
based on video object（视频对象）
entity in scene that user can manipulate and access
video object planes（视频对象区）
instances of video objects at a given time
Example of Sprite Coding of Video
Sequence
The MPEG-4 Video Image Coding
Scheme? An important
advantage of the
content-based
coding approach
MPEG-4 is that the
compression
efficiency can be
significantly
improved for some
video sequences by
using appropriate
and dedicated
object-based
motion
prediction,tools” for
each object in a
scene
Media integration of text and
graphics（文本和图形集成）
3d graphics（三维图形）
like VRML including script nodes
face animation（脸部动画）
face definition parameters (FDPs)
face animation parameters (FAPs)
2d mesh encoding（二维网格）
dynamic mesh,a temporal sequence of 2d triangular
meshes
texture coding via wavelets（小波纹理编码）
Face definition parameters
a number of feature points on a neutral face
face
animation
parameters
2d mesh decoding
mesh vertices points can move in 2d
2d mesh of fish
2d mesh augmentation of fish
the letters are synthetically overlaid on the video object and
move in synchronization with it
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
URLs
