Transcript MPEG-4 Technical

MPEG-4
Technology Strategy Analysis
Sonja Kangas, Mihai Burlacu
T-109.551 Research Seminar on Telecommunications Business II
Telecommunications Software and Multimedia Laboratory
Helsinki University of Technology
Organisations Behind MPEG 4
MPEG (Moving Picture Experts Group)
3GPP (The 3rd Generation Partnership Project)
Internet Streaming Media Alliance (ISMA)
M4IF´s (MPEG-4 Industry Forum)
Wireless Multimedia Forum's (WMF)
+ others
• Backwards compatible with older MPEG1 and MPEG2
• Object Oriented Logic support
• Deals with "media objects" ->generalization for the visual and audio content to handle
both natural and synthetic objects
• Coding/decoding of the media content must not be related to any transmission medium
MPEG1
• released in 1992. standard for storable multimedia, mostly for CD-ROM systems. MPEG1designed for compressing video, but sound compressing format (MP3) format became
more popular. The typical transfer speed of MPEG-1 is VHS quality video (1,5 Mb/s).
MPEG2
• released in 1994. Meant for Digital TV. Used to DVD and satelite digital broadcast.
• Typical rates range from 1.5 Mb/s up to 24 Mb/s
MPEG4
• released in 2000. Targeted for IP networks streaming applications.
• Very wide bitrate ranges from few kb/s to tens of Mb/s
Transmission/Storage Medium
• Transmission/Storage Medium independent of MPEG-4 spec.
• It specifies the physical layer, digital storage requirements a.so.("raw data"
• Upper network layer (like UDP/IP, ATM, MPEG2 Transport Stream) to handle the
actual physical network properties
Delivery Layer
• Media object conveyed by multiple elementary streams.
• Content of the streams: audio-visual object data, scene description information,
control information in the form of object descriptors
• The sync layer passes the elementary streams to delivery layer through the DMIFapplication interface (DAI);
• Defined a single, uniform interface to access multimedia from a multitude of delivery
technologies ((DAI) used for bringing broadcast material and local files)
• The DAI defines procedures for initializing an MPEG-4 session and obtaining
access to the various elementary streams that are contained in it. Similar to ftp
protocol
• FlexMux is an optional tool
• Quality of Service available to content provider. (DAI allows the user application to
specify it for the necessary streams
Sync Layer
• Synch Layer handles the synchronization of elementary streams and also provides
the buffering. It is achieved through time stamping within elementary streams.
• Synchronization Layer does not contain information for frame demarcation
Multimedia Layer
• Converts the multimedia elements into elementary streams.
• Difference between synthetic objects and natural objects visible at this stage
• Object descriptors : identify information type from elem streams and identify the
group of streams related to a media object
• Media object carried in own elementary streams.
• The scene description information defines the spatial and temporal position of the
media objects, their behavior over time
• Scene composition described with a binary language for scene description called
BIFS (Binary format for scenes). Describes an efficient binary representation of the
scene graph. Similar to VRML. Difference: VRML textual, BIFS binary. BIFS defined
for streaming mainly. Scene sending: send initial img followed by timestamp modifications to the scene
• Upper elements make interactive applications easy to be implemented.
Dynamic Image Coding
• Static Texture Coding - done with Discrete Wavelet Transform
• Usage of reversible variable length codes.
AUDIO
• "General Audio (GA)" coders. Input signal is first decomposed into a
time/frequency (t/f) spectral representation by means of an analysis
filterbank, which is then subsequently quantized and coded.
• Bitrate scalability important feature
• Synthetic sound support + old traditional sound compressions tool available
Business strategies: MPEG-4 next big thing?
Expectations (industry viewpoint):
• Video to be MPEG-4’s main application area
• Industry people both servers and consumers of MPEG-4
• MPEG-4 deployment started in 2002
• Eencoder/server/player solution seems to be good idea
• Software encoders vs. hardware encoders
• Priority: performance, availability and price
• Wireless video does not lead the growth of MPEG-4
Expectations (consumers):
• What MPEG-4?
Video on mobile devices
1. The growth of data bandwidth in mobile networks
2. Improved video compression technologies
3. Improved camera and display technologies
Video applications in wireless devices
- video conference/telephony, MMS, video messanging, video streaming
(advertisement, entertainment, education, communication...)
+ Media integration (multiple media):
Interactive eLearning, interactive advertising, network games, media-on
demand, MP3, HDTV, digital cable TV, personal video recording (PVR) etc.
An example: The mobile entertainment value web (possibilities for MPEG-4)
Areas of application
Wide: digital television, multimedia, video, audio, wireless...
Key issues
- new ways of using and accessing media
- streaming and downloading video
- interoperability
- secure communication and pay-per-view
- "mixing the best of Shockwave, Flash, VRML, and digital video into a single file
format, server and player"
New business opportunities
- business opportunities for established market players and newcomers to digital
video and multimedia
- MPEG-4 devices for home entertainment systems (set-top-boxes, DVD players,
handheld devices...), wireless, other
- Rich (multi)media across broadcast, broadband, wireless and wired networks
- New ways of experiencing media! (compare to the content industry trends)
- Different categories of excellence (web): hw/sw, real time/non-real time -read by the same decoders
Problems in the paradise...
+ Apple: Internet Streaming Media Alliance and other consortiums for and against
+ MPEG-4 is very extensive standard -- much more than Real and Microsoft
- The static nature of the standard is its weakness
- Future development of MPEG-4 or another standard?
- Competing video codecs: QuickTime, Real, Windows Media
- IPR issues
- patents and discoveries behing MPEG-4 (problems?)
Thank you!