MPEG-4: A 15-minute Introduction

MPEG-4:MPEG-4: A 15-minute A 15-minute IntroductionIntroduction

Denis Denis LebelLebel

presented by

MUMT-611: Music Information Acquisition, Preservation, and MUMT-611: Music Information Acquisition, Preservation, and RetrievalRetrieval 22

Presentation OutlinePresentation Outline

IntroductionIntroduction

MPEG-4 OverviewMPEG-4 Overview

MPEG-4 AudioMPEG-4 Audio• Advanced Audio Coding (AAC)Advanced Audio Coding (AAC)

ConclusionConclusion

References + LinksReferences + Links



What is MPEG-4?What is MPEG-4?

• A standard for multimedia content deliveryA standard for multimedia content delivery

• Introduced in late 1998Introduced in late 1998

• Developed by the Moving Picture Experts Group (MPEG)Developed by the Moving Picture Experts Group (MPEG)

• Goes beyond 2D video and audioGoes beyond 2D video and audio

• Provides a standardized framework for multiple mediaProvides a standardized framework for multiple media



A little bit of history…A little bit of history…

• MPEG-1: (1991)MPEG-1: (1991) 3 Layers of audio coding complexity (MP3 = MPEG-1 Layer 3 Layers of audio coding complexity (MP3 = MPEG-1 Layer 3)3)

Up to 2 audio channelsUp to 2 audio channels Video coding for Video-CDVideo coding for Video-CD Standard composed of 5 partsStandard composed of 5 parts

• MPEG-2: (1994)MPEG-2: (1994) Advanced Audio Coding (AAC)Advanced Audio Coding (AAC) Up to 5.1 audio channelsUp to 5.1 audio channels Enhanced video codingEnhanced video coding Basis for coding format of DVD, Digital Television and Basis for coding format of DVD, Digital Television and broadcastbroadcast

Standard composed of 10 partsStandard composed of 10 parts



A little bit of history…A little bit of history…

• MPEG-3: (N/A)MPEG-3: (N/A) Not MP3!Not MP3! Originally meant for HDTVOriginally meant for HDTV Not released since HDTV requirements already Not released since HDTV requirements already present in MPEG-2present in MPEG-2

• MPEG-4: (late 1998)MPEG-4: (late 1998) Some applications: Web media streaming, CD Some applications: Web media streaming, CD distribution, Videophone, broadcast televisiondistribution, Videophone, broadcast television

Emphasis is on higher functionality rather than Emphasis is on higher functionality rather than better compression efficiencybetter compression efficiency

Standard composed of 22 partsStandard composed of 22 parts










MPEG-4 StandardMPEG-4 Standard

• Meant to become the universal language between Meant to become the universal language between broadcasting, movie and multimedia applicationsbroadcasting, movie and multimedia applications

• Provides standardized ways of representing the Provides standardized ways of representing the various elements of multimedia content (e.g., audio, various elements of multimedia content (e.g., audio, video, …)video, …)

• Allows for intellectual property management and Allows for intellectual property management and protectionprotection



MPEG-4 ModelMPEG-4 Model

• Describes the multimedia content in an object-Describes the multimedia content in an object-oriented wayoriented way Media elements are Media elements are objectsobjects part of a part of a scenescene

• Media objects can be Media objects can be naturalnatural or or syntheticsynthetic

• Objects can be encoded and transmitted Objects can be encoded and transmitted separatelyseparately in in their their own streamown stream

• Composition of the scene occurs Composition of the scene occurs after transmission after transmission and decodingand decoding In MPEG-2, composition happens In MPEG-2, composition happens before encodingbefore encoding



MPEG-4 ModelMPEG-4 Model

• MPEG-4 consists of large number of MPEG-4 consists of large number of toolstools grouped in grouped in profilesprofiles An application may use a An application may use a set of profilesset of profiles based on based on the functionalities requiredthe functionalities required

• Profiles exist at different Profiles exist at different levelslevels of complexity of complexity

• MPEG-4 consists of closely interrelated but distinct MPEG-4 consists of closely interrelated but distinct individual individual partsparts



MPEG-4 PartsMPEG-4 Parts• Part 1:Part 1: SystemsSystems• Part 2:Part 2: VisualVisual• Part 3:Part 3: AudioAudio• Part 4:Part 4: ConformanceConformance• Part 5:Part 5: Reference SoftwareReference Software• Part 6:Part 6: Delivery Multimedia Integration Delivery Multimedia Integration

Framework (DMIF)Framework (DMIF)• Part 7:Part 7: Optimized Reference SoftwareOptimized Reference Software• Part 8:Part 8: Carriage over IP NetworksCarriage over IP Networks• Part 9:Part 9: Reference HardwareReference Hardware• Part 10:Part 10: Advanced Video CodingAdvanced Video Coding• Part 11:Part 11: Scene Description and Application Scene Description and Application

Engine (BIFS)Engine (BIFS)



MPEG-4 PartsMPEG-4 Parts• Part 12:Part 12: ISO Based Media File FormatISO Based Media File Format• Part 13:Part 13: Intellectual Property Management and Intellectual Property Management and

Protection (IPMP)Protection (IPMP)• Part 14:Part 14: MPEG-4 File FormatMPEG-4 File Format• Part 15:Part 15: AVC File FormatAVC File Format• Part 16:Part 16: Animation Framework eXtension (AFX)Animation Framework eXtension (AFX)• Part 17:Part 17: Timed Text Subtitle FormatTimed Text Subtitle Format• Part 18:Part 18: Font Compression and StreamingFont Compression and Streaming• Part 19:Part 19: Synthesized Texture StreamSynthesized Texture Stream• Part 20:Part 20: Lightweight Scene Representation Lightweight Scene Representation

(LASeR)(LASeR)• Part 21:Part 21: MPEG-J Graphical Framework eXtension MPEG-J Graphical Framework eXtension

(GFX)(GFX)• Part 22:Part 22: Open Font Format Specification (OFFS)Open Font Format Specification (OFFS)



MPEG-4 ApplicationsMPEG-4 Applications• BroadcastingBroadcasting• Collaborative Scene VisualizationCollaborative Scene Visualization• ““Content-based” Storage and RetrievalContent-based” Storage and Retrieval• Digital TelevisionDigital Television• DVDDVD• Mobile MultimediaMobile Multimedia• Real-Time CommunicationsReal-Time Communications• Web Streaming (video, audio, …)Web Streaming (video, audio, …)• Studio Post-ProductionStudio Post-Production• Virtual MeetingVirtual Meeting• ……









MPEG-4 AudioMPEG-4 Audio

DescriptionDescription• A family of audio coding algorithmsA family of audio coding algorithms

• Spans a very broad range of bit ratesSpans a very broad range of bit rates

• Uses Advanced Audio Coding (AAC) to encode the audio Uses Advanced Audio Coding (AAC) to encode the audio signalsignal

• MPEG-4 is a container file:MPEG-4 is a container file: Song titleSong title Album coverAlbum cover …… AudioAudio

• Digital Rights Management (DRM) can be appliedDigital Rights Management (DRM) can be applied


MPEG-4 AudioMPEG-4 Audio

File ExtensionFile Extension• MP4:MP4:

Can be any MPEG-4 file (e.g., video, audio, …)Can be any MPEG-4 file (e.g., video, audio, …) Does not necessarily contain MPEG-4 audioDoes not necessarily contain MPEG-4 audio

• MA4:MA4: Stands for MPEG 4 AudioStands for MPEG 4 Audio

• M4P:M4P: MPEG 4 Audio files that are MPEG 4 Audio files that are protectedprotected (using DRM) (using DRM) Used by iTunes Music StoreUsed by iTunes Music Store

• AAC:AAC: Audio files that are not contained in a MPEG-4 Audio files that are not contained in a MPEG-4 container filecontainer file

• Some software support M4A, others support MP4Some software support M4A, others support MP4 Really only a file extensionReally only a file extension


Advanced Audio CodingAdvanced Audio Coding

Some Improvements over MPEG-1 Audio:Some Improvements over MPEG-1 Audio:• Sampling Frequencies: 8 - 96Hz Sampling Frequencies: 8 - 96Hz (official MP3: 16 - (official MP3: 16 -

48Hz)48Hz)

• Up to 48 ChannelsUp to 48 Channels (up to 2 channels)(up to 2 channels)

• Higher efficiency and simpler filterbank (pure MDCT)Higher efficiency and simpler filterbank (pure MDCT) (hybrid (hybrid transform)transform)

• Higher coding efficiency for stationary signals (larger block Higher coding efficiency for stationary signals (larger block size)size)

• Higher coding efficiency for transient signals (smaller block Higher coding efficiency for transient signals (smaller block size)size)

• Better handling of high frequencies (i.e. > 16kHz)Better handling of high frequencies (i.e. > 16kHz)

• More flexible joint stereoMore flexible joint stereo


Advanced Audio CodingAdvanced Audio Coding

Some new features introduced in AACSome new features introduced in AAC• Pure Modified Discrete Cosine Transform (MDCT)Pure Modified Discrete Cosine Transform (MDCT)

• Longer/Shorter windowsLonger/Shorter windows

• Ability to toggle M/S stereo or intensity stereo on a Ability to toggle M/S stereo or intensity stereo on a subband basissubband basis

• Temporal Noise shaping (TNS)Temporal Noise shaping (TNS)

• Perceptual Noise Substitution (PNS)Perceptual Noise Substitution (PNS)

• Long Term Prediction (LTP) for stationary signalsLong Term Prediction (LTP) for stationary signals










MPEG-4 provides a broad framework for efficient MPEG-4 provides a broad framework for efficient delivery of richer multimedia contentdelivery of richer multimedia content

MPEG-4 Audio features better sound quality in MPEG-4 Audio features better sound quality in comparison to MPEG-1 due to its Advanced Audio comparison to MPEG-1 due to its Advanced Audio Coding (AAC)Coding (AAC)


ReferencesReferences

Brandenburg, K. 1999. MP3 and ACC explained. Brandenburg, K. 1999. MP3 and ACC explained. Proceedings of the Audio Proceedings of the Audio Engineering Society Conference on High Quality Audio CodingEngineering Society Conference on High Quality Audio Coding..

Pereira, F., and T. Ebrahimi. 2002. Pereira, F., and T. Ebrahimi. 2002. The MPEG-4 bookThe MPEG-4 book. Upper Saddle River, . Upper Saddle River, NJ: Prentice-Hall.NJ: Prentice-Hall.

International Organisation for Standardisation. 2002. International Organisation for Standardisation. 2002. Overview of the Overview of the MPEG-4 standard, V.21 (Jeju Version)MPEG-4 standard, V.21 (Jeju Version)..

International Organisation for Standardisation. 1999. International Organisation for Standardisation. 1999. MPEG-4 MPEG-4 applicationsapplications..

International Organisation for Standardisation. 2003. International Organisation for Standardisation. 2003. MPEG-4 MPEG-4 requirements, V.18 (Trondheim revision)requirements, V.18 (Trondheim revision). .

MPEG-4 Industry Forum. 2002. MPEG-4 Industry Forum. 2002. MPEG-4: The media standardMPEG-4: The media standard..


LinksLinks

http://www.chiariglione.org/mpeg/http://www.chiariglione.org/mpeg/

http://www.m4a.com/http://www.m4a.com/

http://www.m4if.org/http://www.m4if.org/

http://www.mpeg.org/http://www.mpeg.org/

http://wikipedia.org/http://wikipedia.org/

MPEG-4: A 15-minute Introduction

Documents

audio channelsvideo

decodingin mpeg

advanced audio coding

standardized framework

advanced video codingpart

media file formatpart

coding format of dvd

avc file formatpart