1TOAST(1)                    General Commands Manual                   TOAST(1)
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NAME

6       toast — GSM 06.10 lossy sound compression
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SYNOPSIS

9       toast [ -cdfpvhualsFC ] [ filename... ]
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11       untoast [ -cfpvhuaslF ] [ filename... ]
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13       tcat [ -vhuaslF ] [ filename... ]
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DESCRIPTION

16       Toast  compresses the sound files given on its command line.  Each file
17       is replaced by a file with the extension .gsm .  If no files are speci‐
18       fied,  the compression is applied to the standard input, and its result
19       is written to standard output.
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21       Toasted files can be restored to something not quite unlike their orig‐
22       inal form by running toast -d , or untoast , on the .gsm-files or stan‐
23       dard input.
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25       The program tcat (the same as running untoast -c  )   uncompresses  its
26       input on standard output, but leaves the compressed .gsm-files alone.
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28       When  files are compressed or uncompressed into other files, the owner‐
29       ship (if run by root), modes, accessed and  modified  times  are  main‐
30       tained between both versions.
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OPTIONS

33       -c     (cat) Write to the standard output; no files are changed.
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35       -d     (decode) Decode, rather than encode, the files.
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37       -f     (force)  Force replacement of output files if they exist.  If -f
38              is omitted and toast (or untoast) is run  interactively  from  a
39              terminal,  the user is prompted as to whether the file should be
40              replaced.
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42       -p     (precious) Do not delete the source  files.   Source  files  are
43              implicitly left alone whenever -c is specified or tcat is run.
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45       -C     (LTP cut-off) Ignore most sample values when calculating the GSM
46              long-term correlation lag during encoding.  (The multiplications
47              that  do this are a bottleneck of the algorithm.)  The resulting
48              encoding process will not produce exactly the  same  results  as
49              GSM 06.10 would, but remains close enough to be compatible.
50              The  -C  option  applies  only  to  the  encoder and is silently
51              ignored by the decoder.
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53       -F     (fast) On systems with a floating point processor, but without a
54              multiplication  instruction,  -F sacrifices standard conformance
55              to performance and nearly doubles the speed of the algorithm.
56              The resulting encoding and decoding  process  will  not  produce
57              exactly  the  same results as GSM 06.10 would, but remains close
58              enough to be compatible.
59              The default is standard-conforming operation.
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61       -v     (version)  outputs the version of toast (or untoast or tcat)  to
62              stdout and exits.
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64       -h     (help)  prints a short overview of the options.
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66       Toast,  untoast and tcat try to guess the appropriate audio data format
67       from the file suffix.  Command line options can also specify  a  format
68       to be used for all files.
69       The following formats are supported:
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71       -u     (μU-law) 8 kHz, 8 bit μU-law encoding (file suffix .u)
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73       -a     (A-law) 8 kHz, 8 bit A-law encoding (file suffix .A)
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75       -s     (Sun audio) 8 kHz, 8 bit μU-law encoding with audio header (file
76              suffix .au)
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78       -l     (linear) 8 kHz, 16 bit signed linear encoding in host byte order
79              with 13 significant bits (file suffix .l)
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81       In  absence of options or suffixes to specify a format, μU-law encoding
82       as forced by -u is assumed.
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PECULIARITIES

85       A four bit magic number is prefixed to  each  32  1/2-byte  GSM  frame,
86       mainly because 32 1/2-bytes are rather clumsy to handle.
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WARNING

89       The compression algorithm used is a lossy compression algorithm devised
90       especially for speech; on no account should it be used for  text,  pic‐
91       tures or any other non-speech-data you consider valuable.
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BUGS

94       Please direct bug reports to jutta@cs.tu-berlin.de.
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SEE ALSO

97       gsm(3)
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101                                     local                            TOAST(1)
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