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Summary: Audio Transmission over the Internet:
Experiments and Observations*
Lopamudra Roychoudhuri, Ehab Al-Shaer, Hazem Hamed and Gregory B. Brewster
School of Computer Science, Telecommunications and Information Systems
DePaul University
Chicago, IL., U.S.A.
{lroychou,ehab,hhamed,brewster}@cs.depaul.edu
Abstract--The performance of IP telephony systems is highly
dependent on the audio codecs and their reaction to packet loss
and instantaneous delays. Understanding the interaction
between audio encoding and the dynamic behavior of the Internet
is significant for designing adaptive audio transport mechanisms.
For this purpose, we conducted a large-scale audio transmission
experiment over the Internet in a 12-month period using various
Internet sites. As a result of this experiment, we have made a
number of new observations to assess the audio quality of G.711
and G.728 codecs under different loss and delay conditions. The
paper also states a number of recommendations for
implementing efficient adaptive FEC and playout mechanisms.
Keywords- packet audio; Internet experiments; audio codecs;
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