Axis 0748-001-EOL Axis M1124-E User Manual

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AXISM1124–ENetworkCamera

Video

ClickSavetoapplythenewsettings.

H.264

H.264,alsoknownasMPEG-4Part10/AVC,isavideocompressionstandardthatprovideshighqualityvideostreamsatlowbitrates.

AnH.264videostreamconsistsofdifferenttypesofframessuchasI-framesandP-frames.AnI-frameisacompleteimagewhereas

P-framesonlycontainthedifferencesfrompreviousframes.

TheH.264streamsettingscanbeconguredfromtheVideo>VideoStreampage.SelecttheH.264tab.Thesettingsdenedinthis

pagewillapplytoallH.264streamsthatdonotuseastreamprole.

TheGOPlengthisthenumberofframesbetweentwoconsecutiveI-frames.IncreasingtheGOPlengthmaysaveconsiderablyon

bandwidthrequirementsinsomecases,butmayalsohaveanadverseaffectonimagequality.

TheAxisproductsupportsthefollowingH.264prole(s):

•Baseline.TheBaselineproleisrecommendedforclientsthatdon’tsupportCABACentropycoding.

•Main.TheMainproleprovideshighercompressionwithmaintainedvideoqualitycomparedtotheBaselineprolebut

requiresmoreprocessingpowertodecode.

•High.TheHighproleprovidesreducedbitrateandhighercompressionwithmaintainedvideoqualitycomparedtothe

Mainprolebutrequiresmoreprocessingpowertodecode.

ThebitratecanbesetasVariablebitrate(VBR)orMaximumbitrate(MBR).VBRadjuststhebitrateaccordingtotheimage

complexity,usingupmorebandwidthforincreasedactivityintheimage,andlessforlowerimageactivity.Whentheactivityin

thesceneincreases,thebitratewouldusuallyincreaseaswell.Ifthereisasurplusinbandwidth,thismaynotbeanissueand

selectingVariablebitrate(VBR)willbesufcient.Butifbandwidthislimited,itisrecommendedtocontrolthebitratebyselecting

Maximumbitrate(MBR).Whentheactivityinthesceneincreases,VBRadjuststhebitrateaccordingtothecomplexity,usingup

morebandwidthforincreasedactivityinthescene,andlessforlowersceneactivity.MBRallowsyoutosetatargetbitratethat

limitsthebandwidthconsumption.

TheMBRtargetbitrateworksliketheceilingofatent.Itlimitsthebitrate,whilemaintainingsomeexibility.Thebitrate

maybounceupanddownwithinthesettargetbutwhenitnearsthesettargetvalue,thelimitationkicksin.However,because

MBRwillalwaysprioritizeacontinuousvideostream,itallowstemporaryovershootsfromthetargetbitrate.Becausesettinga

targetvaluepreventsthebitratefromincreasing,framerateandimagequalityareaffectednegatively.Topartlycompensatefor

this,selectwhichvariableshallbeprioritized,framerateorimagequality.Notsettingaprioritymeansthatframerateand

imagequalityareequallyaffected.

Thecurrentbitratecanbesettoappearastextoverlay.UnderOverlaySettings,selectIncludetextandenterthemodier

#bintheeld.

Toapplythesettings,clickSave.

Axis’ZipstreamTechnology

Zipstreamisabitrate-reductiontechnologyoptimizedforvideosurveillance.ZipstreamreducestheaveragebitrateintheH.264

streambyremovingunnecessarydataandmakesitpossibletoallowhigherresolutions,reducestoragecostortokeeprecordingsfor

alongertime.Toreducethebitrate,Zipstreamreducesthenumberofbitsintheareasoftheimagethatarelessinterestingfroma

videosurveillanceperspective,forexamplethebackground.Imagedetailsthatareimportantforforensicvideoanalysis,forexample

facesandlicenseplates,arepreservedwithenoughnumberofbits.

TheseZipstreamstrengthoptionsareavailable:

•Off.Zipstreamdisabled.

•LowestZipstreamstrength.Lowbandwidthreduction.Novisiblequalitydegradationinmostscenes

•MediumZipstreamstrength.Mediumbandwidthreduction.Limitedvisualqualitydegradationinnotprioritizedareasin

somescenes

•HighestZipstreamstrength.Highbandwidthreduction.Visiblequalitydegradationinnotprioritizedareasinmanyscenes

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Axis 0748-001-EOL M1124-E Outdoor Network Video Camera 0748-001

Axis M1124-E User Manual - Page 20