NAME

pcmfade - create a fade-in or fade-out in a PCM file

SYNOPSIS

pcmfade 0%-offset 100%-offset file

DESCRIPTION

pcmfade can be used to create a fade-in (0%-offset < 100%-offset) or a fade-out (0%-offset > 100%-offset) in a raw PCM audio file.

OPERANDS

The following operands are supported:

0%-offset

Specify the file offset at which the volume should be faded to 0% (i.e. silence).

100%-offset

Specify the file offset at which the volume should reach the original level.

file

The file to work with. The file must be a raw PCM audio file: linear signed 16 bits, stereo, 44.1 kHz, intel byte order (``little endian''). This is also known as ``CD quality'' audio format. It is created by tosha(1), for example.

WARNING: The file is modified in-place. If the original file contents need to preserved, you must make a backup copy before using pcmfade!

OFFSETS

File offsets can be specified in two ways: as time stamp, or as sample count. Note: 1 sample = 4 bytes (16 bits left and 16 bits right). In both cases, the offset can be relative to the beginning of the file, or (if prefixed with a minus sign) relative to the end of the file. Thus, the offset syntax is:

[-] [minutes] : seconds | [-] samples

minutes

is an integer value, which may be omitted. The default value is 0. Note that the colon may not be omitted, because it indicates the time stamp syntax. if the colon is missing, the value is assumed to be a sample count, not a time stamp.

seconds

is an integer or floating point value. It can be larger than 60, for example ``1:80'' is the same as ``2:20'', and ``:120.5'' is the same as ``2:00.5''.

samples

is an integer value (1 sample = 4 bytes). There are 44100 samples per second.

If no sign is specified, the offset is assumed to be relative to the beginning of the file. If a minus sign is present, the offset is relative to the end of the file. For example, if the length of the file is four minutes, ``-1:15'' specifies the same offset as ``2:45''.

SEE ALSO

tosha(1), pcmplay(1), sox(1), intro(1)

BUGS

Yes. This is an alpha version.

AUTHOR

Copyright (C) 1997-1999
Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de>
All rights reserved. For more information, please refer to the file LICENCE which is included with the source distribution.

Internet references:
http://www.heim3.tu-clausthal.de/~olli/tosha/
That's the homepage of the CD-DA reader tosha(1) which also contains the latest version of pcmfade.