Network Monitoring Software from GL Communications, Inc.

Audio Processing Utility (APU) -- PKB070

Audio Processing Utility (APU) -- PKB070 -- View Larger Image
Audio Processing Utility (APU) -- PKB070-Image

Audio processing utility is a pre-processing application used for manipulating the input audio (tones, and voice) files with impairments such as delay, noise, acoustic echo, line echo, and double talk. An echo file is generated if a corresponding line or acoustic echo filter is specified. It analyzes the given coefficients files and calculates the applied delay & ERL. The degraded audio output file can then be visually analyzed or used for further speech analysis with GL’s Voice Quality Testing, Digital Echo Canceller & other applications.

APU (Audio Processing Utility) is designed to produce a specific configurable degraded file for a given input file. An echo file can also be generated if a corresponding line or acoustic echo filter is specified. In addition, if two files are specified as input files, then, the echo path characteristics will be calculated.

Typical applications

  • P.56 active speech level algorithm testing
    For a well-defined input file, APU will generate a precisely controlled degraded file. This degraded file can be used to test P.56 active speech level algorithm using applications
  • VQT (Voice Quality Testing)
    The input voice file and the controlled degraded file can be fed into the VQT algorithm and test VQT applications
  • EC (Echo Canceller) testing
    The input (reference file) file and the echo file can be used to test the EC. APU can generate line echo and acoustic echo files, and test line EC and acoustic EC, which makes it unique.
  • Offline echo analysis
    The offline echo analysis function of APU will analyze the the stimulus & degraded signal files and calculate the echo path filter coefficients, ERL and delay.
Main Features

  • Generates echo files with appropriate acoustic & hybrid echo
  • Generates degraded voice files with noise, power level, & interference
  • Supports high quality voice over IP, with substantial packet delay and loss (PacketGen™)
  • Generated files can be used to test VQT, ECs, & P.56 active speech level.
  • Supports A-law encoded PCM, µ-law encoded PCM, Windows PCM (*.wav), and 16-bit Intel linear PCM audio files
  • Supported Codecs are G.711 µ-law, G.711 A-law, G.723.1, G.726, G.729, G.729a, G.729b, G.729ab, G.729e, G.729g, iLBC (20ms and 30ms frame)
  • Analyzes filter coefficients, ERL (Echo Return Loss), and delay from the generated files
  • Supports line echo filter model of ITU-T G168 specification and three proprietary acoustic echo filter models.
  • Graphical representation of output files