Hi Jan,

I expected it to start with silence and was just checking, however Bobs
file does _not_ start with silence, although he claimed to pad 10
seconds at the beginning. That's why I wanted to know the actual command
in use.

cheers, Erich

On 24.09.2016 17:41, Jan Stary wrote:
> 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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