Answer 8
A big problem with many aggressive voice-compression algorithms used in communications systems (especially variable bit-rate algorithms) is that they have a "gate" or "threshold" function, below which they don't code anything at all. If the person at the other end is in an environment with any amount of acoustical background noise, you hear this noise cut in and out with his speech, which really gives the strong impression that the connection is cutting in and out. A really good implementation actually measures the background noise level at the encoder and periodically sends a parameter to the decoder to set the level of locally-generated comfort noise.

Contributor: Dave Tweed

Published: July-2002