Windows Media Video 9: overview and applicationsIntroduction to windows mediaA wide range of applicationsEnd-to-end deliveryAuthoringDistributionPlaybackDigital rights managementWindows Media Video 9: overviewStructure of the codecMetrics and design issuesInnovationsWindows Media Video 9: detailed descriptionAdaptive Block Size Transform16 Bit transformsMotion compensationSub-pixel filtersChrominance channelQuantization and dequantizationAdvanced entropy codingLoop filteringInterlace codingField picture codingFrame picture coding modeAdvanced B-frame codingOverlap smoothingLow-rate toolsFading compensationExperiments and observationsWMV-9 compared to MPEG-2 and MPEG-4WMV-9 Compared to H.264/AVCResults from the DVD Forum video codec testsComputational complexityInferencesStandardization of WMV-9SummaryAcknowledgementsReferencesSignal Processing: Image Communication ] (]]]]) ]]]–]]]Windows Media Video 9: overview and applicationsSridhar Srinivasan, Pohsiang (John) Hsu, Tom Holcomb, Kunal Mukerjee,Shankar L. Regunathan, Bruce Lin, Jie Liang, Ming-Chieh Lee,Jordi Ribas-Corbera*Windows Digital Media Division, Microsoft Corporation, Redmond, WA 98052, USAAbstractMicrosoftsWindows Media 9 Series is a set of technologies that enables rich digital media experiences across manytypes of networks and devices. These technologies are widely used in the industry for media delivery over the internetand other media, and are also applied to broadcast, high definition DVDs, and digital projection in theaters.At the core of these technologies is a state-of-the-art video codec called Windows Media Video 9 (WMV-9), whichprovides highly competitive video quality for reasonable computational complexity. WMV-9 is currently understandardization by the Society of Motion Picture and Television Engineers (SMPTE) and the spec is at the CD(Committee Draft) stage.This paper includes a brief introduction to Windows Media technologies and their applications, with a focus on thecompression algorithms used in WMV-9. We present analysis, experimental results, and independent studies thatdemonstrate quality benefits of WMV-9 over a variety of codecs, including optimized implementations of MPEG-2,MPEG-4, and H.264/AVC. We also discuss the complexity advantages of WMV-9 over H.264/AVC.r 2004 Elsevier B.V. All rights reserved.Keywords: Video coding; Windows media; Codec standards1. Introduction to windows mediaWindows Media 9 Series is the latest generationof digital media technologies developed by Micro-soft [13]. Although the origins of Windows Mediafocused on streaming compressed audio and videoover the Internet to personal computers, the visionmoving forward is to enable effective delivery ofdigital media through any network to any device.1.1. A wide range of applicationsFig. 1 illustrates a variety of examples of howWindows Media technology is being used today.In addition to Internet-based applications (e.g.,subscription services, video on demand over IP,web broadcast, etc.), content compressed withWindows Media codecs is being consumed by awide range of wired and wireless consumerelectronic devices (e.g., mobile phones, DVDplayers, portable music players, car stereos, etc.)[27]. Windows Media content can also be deliveredto consumers in physical formats—for instance,ARTICLE IN PRESS*Corresponding author.E-mail address: [email protected] (J. Ribas-Corbera).0923-5965/$ - see front matter r 2004 Elsevier B.V. All rights reserved.doi:10.1016/j.image.2004.06.005using the secure digital (SD) memory card [12],oron CD or DVD using the HighMATtformat [24].Recently high definition (HD) movies (such as‘‘Terminator 2’’ and ‘‘Step into liquid’’) have beenreleased commercially on DVDs using WindowsMedia, and the DVD Forum has adopted theWindows Media Video 9 (WMV-9) codec asmandatory for the next generation HD DVDformat.In the terrestrial and satellite broadcast space, arecent project at the International BroadcastingConvention (IBC) demonstrated how to deliverWindows Media 9 Series content via DVB-T andDVB-S [21]. As another example, Windows Mediatechnology is also used to compress movies in HDand multi-channel audio for projection in com-mercial theaters. For example, the popular ‘‘BMWFilms’’ and independent films from the ‘‘SundanceFestival’’ were compressed and encrypted inWindows Media, distributed electronically, andprojected digitally in numerous public theaters inthe US.1.2. End-to-end deliveryAll of the applications mentioned thus farrequire a set of building blocks or componentsthat permit the deployment of complete end-to-end solutions. The fundamental components ofWindows Media 9 Series are illustrated in Fig. 2and can be classified in three steps: authoring,distribution, and playback. In addition, digitalrights management (DRM) is a key componentthat is distributed across the entire media datapath.1.2.1. AuthoringAuthoring is the process of creating andencoding digital media. The basic encoding soft-ware provided by Microsoft is called WindowsMedia Encoder 9 Series. It is a flexible softwareencoder that can compress audio and videosources for live or on-demand streaming by usingthe Windows Media codecs.At the same time, there are alternative encodingsolutions provided by third parties that are builton top of the Windows Media porting kits (e.g.,hardware encoders from companies such asHarmonic, Optibase, Tandberg Television, TexasInstruments, etc.) or the Windows Media softwaredevelopment kits (SDKs) (e.g., software encodersfrom companies like Accom, Adobe, Avid, Dis-creet, Quantel, etc.).1.2.2. DistributionThe distribution of content compressed withWindows Media codecs over the Internet isgenerally done by a Windows Media Servicesserver. Windows Media Services version 4.1 is anoptional component in Windows 2000 Server, andWindows Media Services 9 Series is an optionalcomponent in Windows 2003 Server. The newserver supports more features for advertising andcorporate scenarios and is twice as scalable—itARTICLE IN PRESSFig. 1. Examples of current Windows Media technology applications.S. Srinivasan et al. / Signal Processing: Image Communication ] (]]]]) ]]]–]]]2doubles the number of customers that can receivea media clip at the same time.A server can either stream the clip (transmit itwith as little delay as possible) or download it(transmit and store it) over the internet into auser’s playback device. The transmission of theclip can be performed live (for news,
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