User guide

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A.2.1.4 FrameTypeDetection
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VQmon/HDidentifiesindividualI,P,andBframesintheGoPandmeasuresthepacket
lossrateandlossdistributionoccurringineachframetyp e.Forunencryptedvideostreams,
VQmon/HDperformspictureheaderdecodingtoidentifyindividualframes,GoPsize,and
framerate.Forencrypted/scrambledstreams,heuristicalgorithmsareappliedinorderto
detectframeboundarie
sandmeasureframesize. 
AsmentionedinSection2.1.1.1,theGoPstructurehasimpactonboththeefficiencyofvideo
encodingandtherobustnessofencodedvideo.VQmon/HDtakesthedifferentI,P,andB
framepacketloss/discardratesintoaccountwhencalculatingperceptualvideoquality
metrics.
A.2.1.5 Per‐frameQualityAnalysi s
VQmon/HDperformsper‐framequalitycalculationusingtheframetype,framesize,
codectype,videobandwidth,andpacketlossdata.Theproportionofeachframetype
impairedbyloss/discardisreported,alongwiththeproportionofBandPframesimpaired
duetothepropagationoferrorsfromearlierreference(IorP)framesintheGoP
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A.2.1.6 PerceptualQualityModel
VQmon/HD’sperce ptualqualitymodelcalculatesestimatedperceptualquality(MOS)
scoresusingtheper‐framequalitymetricsandcontentanalysisasinputs.Thecalculation
modelconsidersthesensitivityofthecontenttoqualitydegradation(e.g.,thatframefreezes
occurringduringahigh‐motionscenewillbemorevisibleandannoyingthanthoseoccurring
duringastaticscene)andoth
ersubjectivefactorssuchasviewerreactiontime,recency,and
temporalmasking(seeSection2.1.3.2).
A.2.1.7 VQmonMarkovModel(VMM)
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VQmon/HDusesafour‐stateMarkovModeltogatherandreportpacketlossstatistics
for“burst”periods(wherequalityissignificantlydegraded)and“gap”periods(periods
betweeneachburstintervalwhenqualityisrelativelyunimpaired).
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