[Asterisk-Dev] u2linear conversion error?

Bob Carlson bob.carlson at sigpro.com
Wed Jun 8 23:01:17 MST 2005

I have been looking at the actual waveforms produced by an audio stream
translated from ulaw into slinear. The source of the ulaw stream is a
Grandstream SIP phone. The wave form is clearly biased in one direction
relative to the x-axis. My guess is that either the SIP phone is making a
mistake in applying the bias factor as it encodes the ulaw or * is
misapplying the bias as it decodes the ulaw.

I could figure this out, but I just don't have the time before I head off
on vacation on Friday. Does anyone know if the Grandstream phone has an
encoding error, or might we be dealing with an error in the * decode?

BTW, I HAVE looked at the * ulaw to slinear code and I have looked at some
reference code that I found. Without some sustained time to study it, I
can't yet be sure if the * code is correct.

Cheers, Bob

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