Axis Q7401 - Page 19

AXISQ7401VideoEncoder
VideoandAudio
•Video&Audio>VideoStream.UnderPreview,clickOpenandselecttheShowpixelcounteroptiontoenablethe
rectangleintheimage.Usethemousetomoveandresizetherectangle,orenterthenumberofpixelsintheWidth
andHeighteldsandclickApply.
•TheLiveViewpageinInternetExplorerwithAXISMediaControl(AMC)inWindows.Right-clickintheimageandselect
Pixelcounter.Usethemousetomoveandresizetherectangle.
Image
ThedefaultimagesettingscanbeconguredunderVideo&Audio>VideoStream.SelecttheImagetab.
Thefollowingsettingsareavailable:
•Resolution.Selectthedefaultresolution.
•Compression.Thecompressionlevelaffectstheimagequality,bandwidthandlesizeofsavedimages;thelowerthe
compression,thehighertheimagequalitywithhigherbandwidthrequirementsandlargerlesizes.
•Rotateimage.Ifrequired,theimagecanberotated.
•Colorsetting.SelecteitherColororBlack&White.Black&WhiteuseslessbandwidththanColor.
•Mirror.Ifrequired,theimagecanbemirrored.
•Maximumframerate.Toavoidbandwidthproblems,theframerateallowedtoeachviewercanbeLimitedtoaxed
amount.Alternatively,theframeratecanbesetasUnlimited,whichmeanstheAxisproductalwaysdeliversthehighest
frameratepossibleunderthecurrentconditions.
•Overlaysettings.SeeOverlay,onpage20.
ClickSavetoapplythenewsettings.
H.264
H.264,alsoknownasMPEG-4Part10/AVC,isavideocompressionstandardthatprovideshighqualityvideostreamsatlowbitrates.
AnH.264videostreamconsistsofdifferenttypesofframessuchasI-framesandP-frames.AnI-frameisacompleteimagewhereas
P-framesonlycontainthedifferencesfrompreviousframes.
TheGOVlengthisthenumberofframesbetweentwoconsecutiveI-frames.IncreasingtheGOVlengthmaysaveconsiderablyon
bandwidthrequirementsinsomecases,butmayalsohaveanadverseaffectonimagequality.
ThebitratecanbesetasVariableBitRate(VBR)orConstantBitRate(CBR).VBRadjuststhebitrateaccordingtotheimage
complexity,usingupmorebandwidthforincreasedactivityintheimage,andlessforlowerimageactivity.CBRallowsyoutoseta
xedTargetbitratethatconsumesapredictableamountofbandwidth.Asthebitratewouldusuallyneedtoincreaseforincreased
imageactivity,butinthiscasecannot,framerateandimagequalityareaffectednegatively.Topartlycompensateforthis,itis
possibletoprioritizeeitherframerateorimagequality.Notsettingaprioritymeansthatframerateandimagequalityareequally
affected.Youmustsaveyoursettingsbeforetheycantakeeffect.
Thecurrentbitratecanbesettoappearastextoverlay.Todothis,selecttheIncludetextcheckboxoptionunderOverlay
Settingsandenterthemodier#bintheeld.
MJPEG
Sometimestheimagesizeislargeduetolowlightorcomplexscenery.Adjustingthemaximumframesizehelpstocontrolthe
bandwidthandstorageusedbytheMotionJPEGvideostreaminthesesituations.SettingtheframesizetotheDefaultsetting
providesconsistentlygoodimagequalityattheexpenseofincreasedbandwidthandstorageusageinlowlight.Limitingtheframe
sizeoptimizesbandwidthandstorageusage,butmaygivepoorimagequality.Topreventincreasedbandwidthandstorageusage,
themaximumframesizeshouldbesettoanoptimalvalue.
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