November 2016 | Technical Report NTIA TR-17-522
Intelligibility of Selected Speech Codecs in Frame-Erasure Conditions
Cite This Publication
Andrew A. Catellier and Stephen D. Voran, “Intelligibility of Selected Speech Codecs in Frame-Erasure Conditions,” Technical Report NTIA TR-17-522, U.S. Department of Commerce, National Telecommunications and Information Administration, Institute for Telecommunication Sciences, November 2016.
Andrew A. Catellier 
and Stephen D. Voran
Abstract: We describe the design, implementation, and analysis of a speech intelligibility test. The test included five codec modes, four frame-erasure rates, and two background noise environments, for a total of 40 conditions. The test protocol required twenty listeners to repeat all words that they heard in short messages with median length of seven words. Each condition was tested using approximately 1100 words total. Listeners’ responses were scored against the original message transcripts to produce a count of words correctly repeated and thus a measure of speech intelligibility. We present results that show exactly how this measure of speech intelligibility drops as frame-erasure rate increases for three of the five codec modes. The remaining two codec modes did not produce valid results due to defects in the reference software provided to us.
Keywords: background noise; speech coding; packet loss; speech intelligibility; audio coding; frame erasures; acoustic noise
For technical information concerning this report, contact:
Stephen D. Voran
Institute for Telecommunication Sciences
(720) 446-6425
svoran@ntia.gov
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