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pcmfade(1)             DragonFly General Commands Manual            pcmfade(1)


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.

                                  21 May 1997                       pcmfade(1)

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