Re: volume extremely low when combining many files

[Jan Stary <hans@stare.cz>]

On Sep 24 07:06:23, erich@eckner.net wrote:
> Hi Bob,
> 
> can you post the command you used to generate that file?
> It is indeed not "silent" at the beginning:
> 
> >sox sound77.wav -n trim 0 9 stats
> 
> DC offset  -0.000002
> Min level  -0.007812
> Max level   0.007812
> Pk lev dB     -42.14
> RMS lev dB    -48.17
> RMS Pk dB     -47.83
> RMS Tr dB     -48.64
> Crest factor    2.00
> Flat factor     2.17
> Pk count       99.0k
> Bit-depth       1/8
> Num samples     397k
> Length s       9.000
> Scale max   1.000000
> Window s       0.050
> 
> However, if I do a pad:
> 
> >sox sound77.wav test.wav pad 10

The manpage says

     pad { length[@position(=)] }
	[...]
	position is optional for the first and last lengths specified
	and if omitted correspond to the beginning and the end of
	the audio respectively.

So if I am reading this right, you are padding
with 10 seconds of silence at the beginning.

Then in particular the first 9 seconds is silence:

> and analyze the result, it's silent:
> 
> > sox test.wav -n trim 0 9 stats
> DC offset   0.000000
> Min level   0.000000
> Max level   0.000000
> Pk lev dB       -inf
> RMS lev dB      -inf
> RMS Pk dB       -inf
> RMS Tr dB       -inf
> Crest factor    1.00
> Flat factor   111.97
> Pk count        794k
> Bit-depth       0/0
> Num samples     397k
> Length s       9.000
> Scale max   1.000000
> Window s       0.050

	Jan


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