[SoX-users] Clipping warnings when applying gain to a file

[Jeremy N. - ml s. u. <jn....@wi...>]

I have a track of a choir singing something.  The sung part of the track 
peaks at -6 dB or
so, but the following applause causes overs (so soxi reports peak levels 
of 0dB).  If I
apply gain of 4dB, of course I realise that the part of the recording 
where the applause
happens will get clipped, but I'm puzzled by the warning messsages that 
sox produces. In
a command like:

   sox --no-clobber infile outfile gain 4

I get messages like:

   sox.exe WARN gain: gain clipped 34 samples; decrease volume?
   sox.exe WARN sox: `outfile' output clipped 13 samples; decrease 
volume?

For each track that I do this too, I always get two messages like that, 
with a bigger number
of samples in the first message than the next one.

Are the messages reporting that two contiguous sections of the file had 
clipping, or are they
describing two phases of sox's processing?  Why are the numbers of 
samples different in the two
messages?

-- 
Jeremy Nicoll - my opinions are my own