BTW, has someone a method at hand to convert WAV (8000, 8, 1) to muLaw?

Thomas Vander Stichele thomas at
Wed Feb 25 00:11:14 GMT 2004

Jorge <j.windmeisser <at>> writes:

> I've found some, but all have the same problem, noise and low volume.
> I've waded through the internet, SOX sources, but till today I've had no luck 
> in getting good sound quality out of the aRts mic input, and it's not the 
> microphone...

gst-launch osssrc ! audio/x-raw-int,channels=2 ! audioconvert !
audio/x-raw-int,channels=1,rate=8000 ! mulawenc ! filesink location=test.mulaw

(I'd have to check why gst-launch is forcing me to specify the channel count, it
should be able to figure out on its own, but ignore that).

Although, I'm not sure you're asking the right question.  There are three parts
to your situation.

a) quality of recording from microphone - affected by your microphone and your
mic input channel.  Is your input level set high enough, for example ?
b) your recording format - I'm assuming you're first recording to wav, 8000 Hz,
8 bit, mono, given your subject.  Since you're using 8bit your noise floor is
already at -48 dB, which is already quite audible.  Assuming your input level
isn't set up correctly you're probably picking up a lot of noise already.
c) your original question of "how to convert to mulaw" is actually unrelated to
a) and b).  Are you sure it's not a problem of having the wrong recording setup
? Start by checking input level and recording to 16 bit wav at 44100 Hz to see
if that is acceptable.


> Greets Jorge

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