Exfo EXpert IPTV Test Tools (FTB-1 / 2 Pro) Uživatelský manuál stáhnout pdf (Strana 59)

Figure 2-8.

VQmon Four-state Markov Model

diagram

A.2.2 Audio Stream Analysis

VQmon/HD’s audio quality analysis algorithm performs real-time analysis of audio stream

packets and generates perceptual quality scores (MOS-A) and other metrics corresponding to

those produced by the video quality analysis algorithm. Like the video stream analysis

algorithm, the audio quality analysis algorithm calculates the impact of time-varying

impairments (i.e., burst packet loss and jitter) and recency on perceptual quality.

VQmon/HD calculates overall multimedia quality (MOS-AV) by measuring both audio and

video perceptual quality and the accuracy of the audio-video synchronization.

High-fidelity audio codecs supported by VQmon/HD include:

• MPEG-1 Layer 1, 2, and 3

• MPEG-2 Advanced Audio Coding (AAC)

• AC-3

• MPEG-4 AAC, Low Delay AAC, and High Efficiency AAC

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