SRConv

Author:         Jean Laroche
Platforms:      NeXT
Prerequisites:  NS2.2 or higher?
Price:          free
Demo:           N/A
To acquire:     ftp://ftp.eecs.umich.edu/pub/nextmusic/Srconv.tar.Z (24k)
Information:    ?
Entry updated:  12 November 1996
Description:    A command-line utility for converting soundfiles to any sampling rate using the DSP.



SRCONV(1)           UNIX Programmer's Manual            SRCONV(1)

NAME
     srconv - convert soundfiles to any sampling rate.

SYNOPSIS
     srconv [ -SIvsosibcrUDK ] sound1 sound2

DESCRIPTION
     srconv is a sampling rate converter implemented on the DSP.
     The -S flag lets you specify the output sampling rate. When
     the original sound is a soundfile, its initial sampling rate
     is read from the header and the sound is converted to the
     sampling rate specified by the -S flag. When the original
     sound is a raw headerless binary file (short ints), you need
     to specify its initial sampling rate using the -I flag
     (srconv automatically recognize the file is not a sound-
     file). When converting binary files, srconv assumes the
     sound is mono, unless you specify it is stereo.  srconv can
     convert mono, stereo soundfiles, convert only one of the two
     channels, or add the two channels and convert the sum (for
     stereo original soundfile).  srconv can swap sound bytes
     before or after converting (or both), for compatibility with
     DEC machines, PCs etc...  srconv can either write its output
     as a soundfile (with a header) or as a raw headerless binary
     file.

OPTIONS
     -v   Verbose.  Gives additional informations.

     -S sampling rate
          Specifies the output sampling rate. To convert header-
          less files from one sampling rate to another, this flag
          should be used in conjunction with the -SI flag.

     -I input sampling rate
          This can be used to specify the sound's original sam-
          pling rate. When the original sound is a soundfile
          (with a header), it's original sampling rate is nor-
          mally read from the header. This option overrides the
          header's sampling rate. When the original sound is a
          headerless binary file, this option specifies its sam-
          pling rate.

     -b   Sounfile output. With this option, the converted sound
          is written in a soundfile with a 28 byte header.

     -si  This can be used to swap the input sound bytes before
          converting. Use this if your sound comes either from a
          DEC machine or from a PC. This option is valid only
          when the original sound is headerless.

     -so  This can be used to swap the output sound bytes after
          converting. Use this if you want the converted sound to
          be in DEC or in PC format. This option is valid only
          with the -b option.

     -cs  converts the sound in stereo mode. Valid either when
          the input sound is a stereo soundfile or when it's a
          raw binary file.

     -cl  converts only the sound's left channel. Valid only when
          the input sound is a stereo soundfile (not valid for
          raw binary files).

     -cr  converts only the sound's right channel. Valid only
          when the input sound is a stereo soundfile (not valid
          for raw binary files).

     -c+  mixes the sound's two channels, and converts them in
          mono. Valid only when the input sound is a stereo
          soundfile (not valid for raw binary files).

     -w   This option makes it possible to rescale the output
          sound. Use this if your output sound clicks. The
          default rescaling value is 0.9. This option is disabled
          when bit faithful conversion is performed.

     -r   This option forces the output header to contain the
          exact frequency you specified with the -S option. Due
          to the way srconv works, it sometimes can't convert
          exactly to the requested sampling rate, but only to an
          approximation. Normally, the approximated sampling rate
          is written in the output sound's header. If you use the
          -r option, the exact requested sampling rate is written
          instead.

     -K filter length
          This can be use to specify the filter length you want
          to use. This length is normally calculated automati-
          cally, so you shouldn't need to use this option.

     -B   This can be use to specify the type of filter windowing
          you want to use. By default, a Hanning window is used,
          giving a rejection of about -40dB to -50dB. It may be
          necessary in some cases to use a Blackman window to get
          more rejection (about -60dB), at the expense of a wider
          transition band. This can be done by use of the -B
          flag.

     -U upward conversion factor
          upward conversion factor. Normally, you don't need to
          use this option.

     -D downward conversion factor
          downward conversion factor. Normally, you don't need to
          use this option.

EXAMPLE
     "srconv -I16000 -S24000 file1 file2" converts file1 from
     16kHz to 24kHz and writes it into a headerless file: file2.

     "srconv -S24000 -b file1.snd file2.snd" converts file1.snd
     from its original sampling rate to 24kHz and writes the out-
     put in the soundfile file2.snd.

SEE ALSO
     sndinfo(1), record, play, fromsnd, tosnd

AUTHOR
     Jean Laroche, June 1992, TELECOM PARIS.