NAME
qwavfade - fade in/out wav files
SYNOPSIS
qwavfade [option]... file...
DESCRIPTION
qwavfade modifies a wav file applying on it a fade in or a fade out or
both.
a fade consists in modifying progressively the level of the wav as if
you were slowly increasing or decreasing the volume. a fade in consists
in increasing the volume starting from a low level at the beginning of
the wav. a fade out consists in decreasing the volume to a low level at
the end of the wav.
OPTIONS
-d <duration>[<format>], --duration=<duration>[<format>]
duration is a positive integer that specifies the duration of
the fade. the value is treated as a sample number unless a
format specifier is used. see the FORMATS section below for
information. the default value is five seconds. this option
overrides the --length option explained below.
-h, --help
show a brief help and exit.
-i, --in
just fade in. don’t fade out. by default, fade in and fade out.
-l <time point>, --length=<time point>
time point specifies the length(=duration) of the fade. see the
TIME POINTS section below for information. this option is quite
similar to the --duration option above. its easier to use though
not as powerful than the previous one. the default value is five
seconds. this option overrides the --duration option explained
above.
-o, --out
just fade out. don’t fade in. by default, fade in and fade out.
-t, --test
this option can be used to create and fade a tests files instead
of modifying to original file. a test file will be created for
each type of selected fade (in or out). the name of the test
file will be fadein.<file> or fadeout.<file. the duration of the
test files is the fade duration plus two seconds.
-v, --verbose
show more detailed info.
-V, --version
show version and exit.
TIME POINTS
the time points is a easier way to specify the length (or duration) of
a fade with a millisecond resolution. here’s its formal form:
[h:[m:]]s[.ms] where
h value is a positive integer meaning hours.
m value is a positive integer meaning minutes.
s value is a positive integer meaning seconds.
ms value is a positive integer meaning milliseconds.
only the seconds specifier is required. here are a couple of examples:
1:23:45.67
2:0.001
FORMATS
the --duration option can have also an optional modifier. if this
modifier is not used, then the value provided with the corresponding
cut option will be interpreted as a number of samples. since most of
the times will be difficult to specify a duration in terms of samples,
the following modifiers are provided:
j value is interpreted as milliseconds.
m value is interpreted as minutes.
s value is interpreted as seconds.
b value is interpreted as bytes.
k value is interpreted as kbytes (1024 bytes).
M value is interpreted as megabytes (1024 kbytes).
in either case, the values specified will be rounded to get an integer
number of samples.
EXAMPLE
suppose you want to fade in and out the fantastic song
live.in.concert.wav using a fade duration of 5 seconds:
first we are going to test:
qwavfade -t -d 7s live.in.concert.wav
hear the test fades:
my-favourite-wav-player fadein.live.in.concert.wav
my-favourite-wav-player fadeout.live.in.concert.wav
if you want to try with another duration, jump to the first step and
change the duration argument.
and if you’re happy with the tests:
qwavfade -d 5s live.in.concert.wav
NOTES
qwavfade doesn’t allow both types of fades (in and out) to overlap. if
you want to fade in and out a wav file, and the two regions to fade
overlap, then probably you made a mistake. in any case, you can do it
fading separately.
BUGS
tests has been done only with 44100 Hz 16 bit stereo files, though it
may work with mono/stereo 8/16 bits files.
AUTHOR
dmanye@etse.urv.es
http://www.etse.urv.es/~dmanye/quelcom/quelcom.html
SEE ALSO
qwavinfo(1), qwavjoin(1), qwavcut(1), qwavsilence(1), qwavheaderdump(1)
qmp3info(1), qmp3join(1), qmp3cut(1), qmp3check(1), qmp3report(1)