Installation guide

When the video is played, the video le rst begins to download to the user’s hard drive, then
playback starts. e video will begin to play when enough of it has downloaded to the user’s hard
drive.eleisservedfromastandardwebserverthroughanHTTPrequest,justlikeanormal
web page or any other downloadable document.
Incomparisontostreamingvideo,there’sreallyonlyoneconsistentbenettoprogressive
download—youdon’tneedastreamingservertodeliverthevideo.Progressivedownloadvideo
can be served from any normal web server. While this can be convenient and potentially
cost-eective, you should keep in mind that progressive downloads have limited seek and
navigation capabilities and users can access and repurpose your content.
When to choose progressive download
Progressivedownloadisagoodchoiceforhobbyistsorwebsitesthathavelowtracrequire-
ments, if they don’t mind if their content is cached on a user’s computer, and they only need to
delivershorterlengthvideos(under10minutes).Youwillneedtostreamyourvideoifyouneed
advancedfeaturesandcontrolovervideodelivery,and/orifyouneedtodisplayvideotolarger
audiences(forexample,severalhundredsimultaneousviewers),trackandreportusageor
viewing statistics, or if you want to oer your viewers the best interactive playback experience.
Streaming delivery also consumes less bandwidth than progressive delivery, because only the
portion of the video that is watched is actually delivered.
Streaming delivery
eabilitytostreamvideoandaudiowasrstavailablewithFlashMX,FlashPlayer6,andFlash
CommunicationServerMX.
When you use streaming delivery, the video les are kept external to the other content, just like
progressivedownloads.DeveloperscanuseActionScriptcommands(andparametersettings
withmediacomponents)toloadexternalvideolesintoaSWFleandplaythembackat
runtime.Infact,theActionScriptcodeneededforstreamingisalmostidenticaltothatfor
progressive download.
However,instreamingvideo,eachclientopensapersistentconnectiontothestreamingserver,
and the server streams the video bits to the client. ose bits are displayed by the viewer and
then immediately discarded.
is tight connection between the server and the client, and the server’s ability to precisely
control and deliver any portion of a stream as requested, enables the developer to take advantage
of some advanced capabilities, including:
• Determiningtheclientbandwidthandservingastreamwithanappropriatebitrate.
• Measuringandtrackingthestream’squalityofdeliveryandswitchingtoalower(orhigher)
bitratestreamifneeded(forexample,ifnetworkcongestionincreases).
• Automaticallygeneratingthumbnailsorplayingshortpreviewsofyourvideoclipwithout
having to create separate images or video clips, and without downloading the entire video in
the background.
• Automaticallycreating“chapters”(withappropriatethumbnails)thatcanbeusedfornaviga-
tion of longer videos, without having to break the video into smaller les.
• Seemlesslyswitchingmidstreamfromonecameraangleoronestream,toanother.
• “Editing”videoclipstogethertocreateonecontinuousvideoforplayback.Forexample,you
couldplaytherst10secondsofclip1,followedbythecontentbetweenthe30-and40-second
marksofclip2,followedbythelast20secondsofclip3.
• Creatingwebcastliveeventsorrecordedeventswhereallviewersaccessthesamecontentatthe
same time.
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