COM 597 Streaming Media

  • Published on
    11-Feb-2016

  • View
    44

  • Download
    0

DESCRIPTION

COM 597 Streaming Media. Class 7 July 13, 2006. General Notes and Comments. Travis Petershagen, Seattle Podcasting Network Pete Grondal, Mobile Devices, TBA. Profiles. Windows Media Encoder uses Profiles What is a profile and how would I use one? - PowerPoint PPT Presentation

Transcript

COM 597Streaming MediaClass 7July 13, 2006General Notes and CommentsTravis Petershagen, Seattle Podcasting NetworkPete Grondal, Mobile Devices, TBAProfilesWindows Media Encoder uses ProfilesWhat is a profile and how would I use one?A profile determines how files or source groups are encodedEach profile may include one or many target audiences, along with video and audio codec informationYou can save the profile and use it repeatedlyTarget AudiencesWhat is the concept of target audiences?This is the naming convention for their multiple bitrate technologyWith it you can select multiple target audiences (bit rates) and weave your different versions into one fileMoving TargetsAn anomaly with the WindowsMedia version of MBR is the video is encoded with multiple qualities of compression.But all the video files share only one Audio fileThere are not multiple audio files only one so choose wiselyThe lowest audience profile will determine your audio settingsAll the video target audiences will share a video screen sizeWhich encoding mode to choose?CBR? VBR?My recommendation:Start with VBRThen two pass CBRThen one pass CBRWhy VBR?VBR when used on proper contentLong and varied in complexityWill give you an appreciably better encoded clip given the same file size. CBR is often using the bits in the wrong places and not having enough available in the difficult spotsThe difference can be as high as 2-to-1Another way to look at it. If two files have the same quality, the VBR file will often be half the size of a CBR fileIf your source is a file and you want to encode with CBR, then two pass is better than one passUsing the frame buffer with CBRWhy use the default of 5 seconds?If you are streaming a longer file (over say 10 minutes) increasing the buffer to 30 seconds will accomplish many of the same increase in quality that VBR does.Windows .NETIf you are streaming over a server with Windows Media Services in Windows .NET Standard or Enterprise editions you can enable Fast StartThis allows the server to burst data to the players and filling the buffer in a shorter time than indicated, thus starting the file quickerMicrosoft Buzzword TranslatorFast Start: Instant on playbackFast Cache: Download and cache the streaming contentFast reconnect: Automatically reconnect to a stream if interruptedFast Recovery: Use forward error correctionOther BuzzwordsReals version of the same stuffTurboPlay It is their rapid playback and seeking technologyInstant On is QuickTimes versionMore BuzzwordsURLs on Media ServersMount point Real and QuickTImePublishing Point Microsoft Windows Media V9Station Windows Media prior to V9A brief introduction to Mobile Media3G (3rd Generation) Mobile NetworksCapable of delivering vast quantities of data & multimediaTarget is handheld devicesMobile networks are evolving from narrowband, circuit-switched networksThese were used primarily for voice and textBrief cont.New networks are broadband and utilize packet switchingDeliver broad range of internet-like media services3G is a real paradigm shift for the telecommunications industryOnce place to look is with the sales of camera phones v. digital still camerasMore mobileSeveral 3G networks are up and running in Europe and AsiaPhones there can include:Multiple cameras supporting real-time, person-to-person video callingVideo messagingPlayback of media content (news, sports, music videos, etc.)A few technological challengesNo agreed to standards. Every company has a better mousetrapIt is the Wild West when it comes to competing technologiesAs opposed to computing where you can assume either MS or Mac, with 3G it is a crap shoot what technology you will need to support, let alone screen size, color depth frame rate and screen direction (vertical or horizontal)MPEG4 is the only video format supported by all phonesYou can visit www.3Gpp.org to review what standards have been defined for MobileHardware problemsHardware variability also represents a significant challenge between mobile devicesEvery few months a new crop of phones with new featuresNot just screen display size and color quality changesMore Hardware problemsOperating systemsProcessing powerMemoryMedia format compatibilityOther technical challenges include:Physical movement of a user from one network cell to anotherSignal strength problems on the edge of a networkUsers proximity to a tower will effect data flowNumber of devices operating simultaneously on the same cellPhysical speed that a device is traveling through the cell (e.g. car)Blog Assignment for class 8Where and how is digital rights management failing. If you can, give a first person account where managing the portability, the delivery or re-use of digital media didnt go the way you think it should.WorkshopCreating and implementing profiles in Windows Media

Recommended

View more >