MPEG-4

XMT-A Format

29/11/2007 1Jean-Baptiste Puibaraud & Julien Pedron

Plan History of MPEG XMT

XMT-A XMT-Ω

From XMT to MP4 Authoring tool

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 2

History of MPEG• Moving Picture Expert Group• Standard to compress audio and digital

data (1988)• Mostly used for Web Application,

Broadcast Television and CD-Distribution

• MPEG-1 (1991)• MPEG-2 (1994)

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 3

MPEG-4• Introduced in 1998 (still developing

standard)• Based on MPEG-1 and MPEG-2• Object-oriented composite files &

support for 3D rendering

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 4

XMT (1/2)• eXtensible MPEG-4 Textual Format• XML based framework for scene

description• Allows authors to exchange information

(XML is readable)• XMT = 2 levels of textual format

XMT-ΩXMT-A

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 5

XMT (2/2)

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 6

Example of MPEG-4 content

XMT-Ω• High Level Description• Defines audio visual objects• Describes temporal behavior and

relationship between the different elements

• XMT-Ω is extended from SMIL• SMIL

Defines markup for timing, layout, visual transition

Used to create interactive content29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 7

XMT-Ω Example

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 8

XMT-A• Low Level Description• Describe precisely each AV element

using MPEG-4 specific features• XMT-A file = set of elements to

represent MPEG-4 system streams• Uses Object Descriptor (OD) to provide

scene description components

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 9

XMT-A Example

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 10

From XMT to MP4 (1/2)

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 11

From XMT-A to MP4 (2/2)

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 12

XMT-Ω description

XMT-A description

Data Structure

BiFS and OD

MP4 File

MP4 Convert

er

Authoring Tool (1/2)

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 13

Authoring Tool (2/2)• GPAC (Open Source)• IBM toolkit for MPEG-4

Set of Java classes and APIs

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 14

References• Wikipedia research on MPEG-4 :

http://en.wikipedia.org/wiki/MPEG-4• Overview of the MPEG-4 Standard :

http://www.chiariglione.org/mpeg/standards/mpeg-4/mpeg-4.htm• GPAC, Open Source Multimedia Framework : Jean Le Feuvre,

Cyril Concolato, Jean-Claude Moissinac• Interactive Contents Authoring System based on XMT and

BIFS : Kyuheon Kim, Injae Lee, Myungseok Ki• An XMT API for Generation of the MPEG-4 Scene

Description : YeSun Joung, Kyuheon Kim• Extensible MPEG-4 Textual Format (XMT) : Michelle Kim, Steve

Wood, Lai-Tee Cheok• MPEG-4 Systems and Applications : Hari Kalva, Lai-Tee Cheok,

Alexandros Eleftheriadis• Design and Implementation of MPEG-4 Authoring Tool :

Kwang-Yong Kim, Hyun-Cheol Kim,Won-Sik Cheong, Kyuheon Kim

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 15

Questions ??

29/11/2007 Jean-Baptiste Puibaraud & Julien Pedron 16