MPEG 4
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  • 1. MPEG 4: The ultimate low bit rate format www.chiariglione.org/mpeg/
  • 2. Overview: ISO/IEC 14496 Coding of audio-visual objects
    • Low bit rate multimedia system - typically less than MPEG 2 video
    • Object based - each element is coded separately
    • Open ended system that can continue to develop in the future
    • Scalable & Interactive
    • Version 1: October 1998
  • 3. Versions Version 1 Version 2
  • 4. Profiles Quality Complexity DVD Video CD Mobiles HDTV Digital cinema MPEG-1 MPEG-2 Advanced Simple Profile Simple Profile MPEG 4
  • 5. Current uses:
    • 3G mobile phones,
    • Portable devices, PDAs, video iPod
    • Interactive television / IPTV
    • New interactive multimedia formats
    • Web pages
    • Interactive music format
    • Security systems
  • 6. Basics:
    • Object based system: using Natural and/or Synthetic objects
    • Makes use of local processing power to recreate sounds and images
    • This makes it one of the most efficient compression systems
  • 7. Basics: Object Types
    • Photos - JPE, GIF, PNG,
    • Video - MPEG-2, Divx, AVI, H.264, QuickTime
    • Speech - CELP, HVXC, Text to Speech
    • Music - AAC, MP3, surround
    • Synthetic music
    • Graphics - Java code
    • Text
    • Animated objects, e.g., talking heads
  • 8. Basics:
    • The selected objects are put together into a 2D or 3D scene
    • In 3D the viewer can change the shape of the image and view it from other positions in the 3D space. Similar to VRML
    • Each object is compressed using the best and most optimum method for that type of data
  • 9. Basics: Virtual Studio
    • Virtual production techniques are increasingly used in TV production
    • Well known chroma-key method using a blue/green screen background
    • Actors are overlaid on to a ‘virtual studio’ background image
    • The composition of the screen image and the sound can now take place in the decoder at home
  • 10.  
  • 11. BIFS:
    • Binary Format for Scene descriptor
    • New description language like HTML but written in binary not in English
    • Has scalable levels for audio and video which can be set by access rights or by interrogation of the receiver to set the best ‘Quality of Service’ (QoS)
  • 12. Synchronised Streaming
    • Each element can be time stamped to synchronise with other objects in the frame
    • Flexi Time: The viewer can vary the time for playback
    • There are 3 types, set by the producer, minimum, maximum and optimal
    • Audio can be set to change pitch or stay fixed
  • 13. Compression : Speech
    • HVXC - Harmonic Vector Excitation Coding
    • CELP - Code Excited Linear Prediction
    • 2 - 24 K bit/sec
    • Synthesised speech:
    • Text to speech synthesis, 200-1200 bit/sec
    • Very low delay, 20 ms, for video phone use MP3 takes too long to encode/decode
  • 14. Compression : Natural Audio
    • MPEG - AAC (Advanced Audio Coding)
    • MP3, AAC, 5.1 surround
    • 6 - 380 K bit/sec
  • 15. Parametric audio coding
    • Synthesised audio :
    • Spectral noise re-synthesised
    • This process separates unique audio sounds from predictable noise shapes which can then be re-synthesised locally
    • Signal is represented by three objects:
      • Transients: localized in time,
      • Sinusoids: localized in frequency,
      • Noise: no strict localization…
  • 16. Parametric audio coding Transients: Castanets
  • 17. Parametric audio coding Sinusoids: Harpsichord
  • 18. Parametric audio coding Noise: Heavy metal
  • 19. Compression : Structured Audio
    • SAOL - Structured Audio Orchestra Language (pronounced sail)
    • Down loadable sound fonts
    • Wavetable synth + GM2 type spec.
    • Any kind of virtual instruments
    • Virtual effects algorithms and mixers
    • MIDI data rates e.g. 300 bit/sec
  • 20. Interactive Audio
    • Download and remix tracks
    • Flash interface and compressed audio loops
    www. yourspins .com
  • 21. Compression : Video
    • Overall MPEG-4 supports a wide range of standards from very small, poor quality, pictures up to HDTV
    • MPEG 1 & 2
    • MPEG 4 - part 2
    • MPEG 4 - part 10, 'Advanced Video Coding’ AVC H.264 - high quality video codec
    • Developed jointly by MPEG and the ITU
  • 22. Compression : Video - H.264
    • Half to one quarter of the normal bit rate of MPEG-2
    • Scalable from 3G to HD
    • More advanced B frame operation where the frame can link to any frame in the video sequence
    • Smaller 4X4 grids of pixels
    • 4 Profiles and 16 Levels
    • Bit rates from 64 Kbps - 240 Mbps
  • 23. Compression : Video
    • Mixture of pixel based and vector graphics
    • Video is no longer a rectangular shape, it can be any shape
    • Synthetic images with bit rates from 5 kbit/sec - 10 Mbit/sec
    • Supports the mapping of video textures onto moving objects and meshes
  • 24. 2D mesh model of a fish By deforming the mesh the fish can be animated
  • 25. Animated Objects:
    • The Animation Framework eXtension, AFX
    • Face animation: The face models are not part of MPEG-4 only the movement codes for the expressions, eye movement, etc.
    • Body animation works in the same way and can be used in games
  • 26. Future Options:
    • MPEG-4 is still being developed and all new parts will work with the old formats
    • Studio quality versions for HDTV
    • Digital cinema 45 - 240 Mbit/sec H.264
    • Home video cameras with MPEG-4 output straight to the web from the hard drive
  • 27. Future Options:
    • Integrated Service Digital Broadcast (ISDB)
    • Newspaper + TV + data
    • Integration with MPEG 7 databases
    • Games with 3D texture mapping
  • 28. Future Options:
    • TeleVision Modelling Language (TVML)
    • Computer generated TV programs + presenters - Max Headroom??
  • 29. Future Options:
    • Information booths
    • Talking objects - fridge, cars, toaster?
    • Security cameras over the web
    • Interactive manuals and training materials
    • New downloadable interactive music format, SAOL
  • 30. MPEG 7
  • 31. MPEG 7
    • Multimedia Content Descriptor Standard
    • Database system to automatically define, organise and search for text, pictures, sound FX, graphics, video clips, songs, music, etc.
    • On-line Music library
    • Automatic identification of music
    • Uses XML to store metadata
  • 32. MPEG 7
    • Proposed uses:
    • Live broadcast monitoring, radio output
    • Digital libraries e.g., image catalogue, musical dictionary, bio-medical imaging, sound FX, film, video and radio archives
    • Cultural services history museums, art galleries, etc.
  • 33. MPEG 7
    • Home entertainment e.g., systems for the management of personal multimedia collections, e.g. music, home video, searching a game, karaoke
    • E-Commerce e.g., personalised advertising, on-line catalogues, directories of e-shops
    • Education e.g., repositories of multimedia courses, multimedia search for support material
  • 34. MPEG 7
    • Investigation services e.g., human characteristics recognition, forensics
    • Journalism e.g. searching speeches of a certain politician using their name, voice or face
    • Multimedia directory services e.g. Yellow Pages, tourist information, geographical information systems
  • 35. MPEG 7
    • Multimedia editing e.g., personalised electronic news service, media authoring
    • Social e.g. on-line dating services
    • Surveillance e.g., traffic control
    http://www.eptascape.com/products/demoflv.htm
  • 36. MPEG 21
  • 37. MPEG 21
    • An infrastructure for the delivery and consumption of multimedia content
    • Users are seen as either creators, consumers, rights holders, content providers, or distributors
  • 38. MPEG 21
    • Every media element is defined as a ‘Digital Item’
    • Metadata defines what media we can use, what we can do with it and who owns it
    • Designed to work with MPEG 4 files and MPEG 7 database