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MPEG-1MPEG --11 Standardsstandards DigitalDigital StorageStorage andand MPEGMPEG-1MPEG --11 StandardsStandards FernandoFernando PereiraPereira Klagenfurt, Austria, October 2008 Audiovisual Compression: from Basics to Systems, Fernando Pereira DigitalDigital AudioAudio andand VideoVideo StorageStorage There are several technologies involved in digital audio and video storage this means in the process of recording a physical support to store the audiovisual (AV) information at hand. One of the most important technologies for AV storage is audiovisual data coding which should provide the necessary compression efficiency and quality but also other storage functionalities such as random access, already provided in analogue recording. Audiovisual Compression: from Basics to Systems, Fernando Pereira RecordingRecording FunctionalitiesFunctionalities …… • Normal video playback – The usual play … • Random access – It shall be possible to access any part of the audiovisual data in a limited amount of time, e.g. 0.5 s. • Reverse playback – Playing at regular speed opposite to the usual temporal direction … • Fast forward and Fast reverse – Faster play (with time compression) in the usual and opposite time directions (more complex form of random access). • Edition – Capability to edit the coded signal in a simple way. Audiovisual Compression: from Basics to Systems, Fernando Pereira MainMain StorageStorage SupportsSupports • Magnetic tape • Magnetic discs • Optical discs • … Audiovisual Compression: from Basics to Systems, Fernando Pereira Storage:Storage: WhichWhich SupportSupport ?? Main factors to be taken into account to select an audiovisual storage support: • Capacity (in MBytes) • Reading speed (in Mbit/s) • Time and form of access (e.g. sequential or random) • Durability • Mobility • Cost • … Audiovisual Compression: from Basics to Systems, Fernando Pereira TheThe BasicBasic CodingCoding ChainChain Original Symbols Bits video Symbol Entropy Generator Encoder (Model) The symbolic coding model depends on the type of data, e.g. audio, video, and on the application requirements, e.g. random access. Audio and video compression are major technologies in the context of digital AV storage. Audiovisual Compression: from Basics to Systems, Fernando Pereira StillStill thethe InteroperabilityInteroperability !! • Interoperability is a basic requirement for digital storage systems, with or without interactivity. • Interoperability requires the specification of international standards for source coding solutions. • To allow some evolution of standard compliant systems and the healthy competition between products, standards should specify the minimum amount of tools possible, typically only the data flow syntax and the decoding process (not the encoding !) Audiovisual Compression: from Basics to Systems, Fernando Pereira TheThe MPEGMPEG FamilyFamily forfor SourceSource CodingCoding • MPEG -1 (1988 -1990): Coding of video and associated audio for a target bitrate of 1.5 Mbit/s - CD Storage (initial target) • MPEG -2 (1990 -1993): Coding of video and associated audio (initially for bitrates up to 10 Mbit/s) - Digital TV (any transmission channel) and DVD • MPEG -3 (X ): Coding of video and associated audio with bitrate up to 60 Mbit/s (finally not defined since MPEG-2 fulfils the needs) - High Definition TV (HDTV) • MPEG -4 (1994 -2008): Coding of video and associated audio (natural and synthetic) based on objects - Interactive multimedia applications Audiovisual Compression: from Basics to Systems, Fernando Pereira StandardsStandards AlongAlong thethe YearsYears ... ... H.264/AVC SVC MVC Audiovisual Compression: from Basics to Systems, Fernando Pereira TheThe RemainingRemaining MPEGMPEG FamilyFamily • MPEG -7 (1997 -2007): Description (high and low-level) of video and audio information (natural and synthetic) - Access to multimedia databases, Electronic Program Guides (EPGs) • MPEG -21 (2001 - 2007): Multimedia framework, notably enabling the transparent and augmented use of multimedia resources across a wide range of networks, devices, and communities, notably for trading (of bits). - Multimedia applications, notably multimedia e-commerce • MPEG -A (2005 -2008): Definition of combinations of tools and profiles (mainly from MPEG) offering more complete and integrated solutions for relevant applications. • … Audiovisual Compression: from Basics to Systems, Fernando Pereira MPEG-1 Standard Audiovisual Compression: from Basics to Systems, Fernando Pereira MotivationMotivation • The emergence of digital storage supports with large capacity and high reading speeds at increasingly lowers costs. • The development of video coding algorithms reaching increasingly higher compression factors for a certain acceptable quality. • The growing electronic integration capability of complex functions in reduced silicon areas (VLSI). • The growing interaction between the telecommunications, computer and consumer electronics industries. • The need to standardize in an area for which the technical development was ready to offer several de facto solutions, taking the opportunity to lower the costs and increase the production. Audiovisual Compression: from Basics to Systems, Fernando Pereira MPEGMPEG-1:MPEG --1:1: StorageStorage SupportsSupports ((~( ~~ 19901990)1990 )) • CD-ROM (Compact-Disc Read Only Memory) - Capacity between 600 MByte and 2 GByte (usually, 650 MB) with a reading speed of about 1.5 Mbit/s (and growing …) • CD-WORM (CD-Write Once Read Many times) - Reading speed of about 8 Mbit/s • Discos Winchester - Capacity between 20 and 400 MByte (now above 1 GByte) with a reading speed of about 8 Mbit/s (now above 20 Mbit/s) • DAT (Digital Audio Tape) - Reading speed of about 7.5 Mbit/s Audiovisual Compression: from Basics to Systems, Fernando Pereira Storage:Storage: WhichWhich SupportSupport ?? Main factors to be taken into account to select an audiovisual storage support: • Capacity (in MBytes) • Reading speed (in Mbit/s) • Time and form of access (e.g. sequential or random) • Durability • Mobility In 1990, the CD-ROM was selected as the most adequate storage support to • Cost offer, for the first time in large scale, • … interactive multimedia signals, mainly due to its large capacity and low cost. Audiovisual Compression: from Basics to Systems, Fernando Pereira DigitalDigital VersatileVersatile DiscDisc (DVD):(DVD): thethe SupportSupport TodayToday !! • The DVD is essentially an evolution of the CD where it is possible to store more video, audio or any other type of digital data. • There are 2 DVD sizes: 12 and 8 cm both 1.2 mm thick (two 0.6 mm glued subtracts). • DVDs may be single-sided or double-sided depending on only one or the two sides store data. • Each side may have one or two storage layers. Audiovisual Compression: from Basics to Systems, Fernando Pereira DVD:DVD: CombiningCombining SidesSides andand LayersLayers Audiovisual Compression: from Basics to Systems, Fernando Pereira DVDDVD oror SuperSuper-CDSuper --CDCD ?? • Capacity (approximate): - SS/SS - 4.7 Gbyte (7 times more than a CD-ROM - 650 MByte) - DS/DL - 17.08 Gbyte (25 times more than a CD-ROM) • The enormous DVD capacity allows the recording of a significant amount of hours of high quality video - SS/SS - 2 hours of video and associated audio - DS/DL – more than 8 hours of video and associated audio Audiovisual Compression: from Basics to Systems, Fernando Pereira DISC MEDIUMS DVDDVD VariantsVariants …… • DVD-ROM: read only, manufactured by a press • DVD-R: recordable once • DVD-RW: rewritable APPLICATION TYPES • DVD-RAM: random access rewritable • DVD+R: recordable once • DVD-Video (containing movies (video and sound)) • DVD+RW: rewritable • DVD-Audio (containing high-definition • DVD-R DL: dual layer record once sound) • DVD+R DL: dual layer record once • SACD (containing high-definition sound) • DVD-VR (containing recorded video and CAPACITIES sound, usually from TV or camcorder) • DVD-5: single sided, single layer, 4.7 gigabytes • DVD+VR (a variation of DVD-Video used (GB), or 4.38 gibibytes (GiB) for recording on +R and +RW discs) • DVD-9: single sided, double layer, 8.5 GB (7.92 GiB) • PS2 DVD (containing games for PlayStation 2) • DVD-10: double sided, single layer on both sides, 9.4 GB (8.75 GiB) • Xbox DVD (containing games for Xbox) • DVD-14: double sided, double layer on one side, single layer on other, 13.3 GB (12.3 GiB) • DVD-Data (containing data) • DVD-18: double sided, double layer on both sides, 17.1 GB (15.9 GiB) Audiovisual Compression: from Basics to Systems, Fernando Pereira TypicalTypical DVDDVD-ROMDVD --ROMROM CapacitiesCapacities • CD-ROM - 12 cm - 1 side/1 layer - 0.68 GB - 1/4 video hour • DVD-5 - 12 cm - 1 side/1 layer - 4.7 GB - 2 1/4 video hours • DVD-9 - 12 cm - 1 side/2 layers - 8.54 GB - 4 video hours • DVD-10 - 12 cm - 2 sides/1 layer - 9.4 GB - 4 1/2 video hours • DVD-18 - 12 cm - 2 sides/2 layers - 17.08 GB - 8 video hours Note: Times are based on MPEG-2 Video coding at 6 Mbit/s. Yes, DivX does better ;-) ! Audiovisual Compression: from Basics to Systems, Fernando Pereira DVDDVD-VideoDVD --VideoVideo andand DVDDVD-AudioDVD --AudioAudio • DVD-Video is a DVD-ROM application targeting offering high quality audio and video using a standard format like: - 1 MPEG-2 video stream - Up to 8 audio MPEG-2, Dolby or Linear PCM channels (48 or 96 kHz, with 16, 20 or 24 bit/sample; maximum rate of 6.144 Mbit/s ) - Up to 32 channels for graphical information, images, navigation menus, parental data, etc • DVD-Audio is a DVD-ROM application targeting offering very high audio quality (Linear
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