qwavfade1

Usage

Overview

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

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:

in either case, the values specified will be rounded to get an integer number of samples.

Examples

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.