Exfo EXpert IPTV Test Tools (FTB-200v2) Uživatelský manuál stáhnout pdf (Strana 31)

31

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8.3.2TransportPacketMetrics

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TransportPacketsare

MPEG‐TSpacketsthat

carryPacket

ElementaryStream

(PES).



Statisticsofthese

MPEG‐TSPacketssuch

aslost,discarded,

corrected,out‐of‐

sequenceand

duplicatedpackets

allowdetectionofthis

majorsourceofvideo

picturedegradation.

JitterMetrics

focusonthePCR

Jitterwhichis

definedasTime

Stamparrival

timejitter.

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PCRJitterisa

majorcontributor

tolossofframes

duetorouteror

STBbuffer

overflow.

RTPPacketMetrics(ifavailable)arestatisticsofRTPprotocol

encapsulation.RTPencapsulationisoptionalandisusedtoprovide

independenttimestampingtovideoandaudio.Butitalsoaddsoverhead

tothetransmission.

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TrackingRTPstatisticsallowsproblemisolationtotheRTPencapsulating

device.

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Exfo EXpert IPTV Test Tools (FTB-200v2) Uživatelský manuál Strana 31