2 .\" Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
3 .\" Universitaet Berlin. See the accompanying file "COPYRIGHT" for
4 .\" details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
11 toast \(em GSM\ 06.10 lossy sound compression
36 Toast compresses the sound files given on its command line.
37 Each file is replaced by a file with the extension
39 If no files are specified, the compression is applied to the
40 standard input, and its result is written to standard output.
42 Toasted files can be restored to something not quite unlike
43 their original form by running toast
47 , on the \&.gsm-files or standard input.
53 ) uncompresses its input on standard output,
54 but leaves the compressed .gsm\-files alone.
56 When files are compressed or uncompressed into other files,
57 the ownership (if run by root), modes, accessed and modified times
58 are maintained between both versions.
63 Write to the standard output; no files are changed.
67 Decode, rather than encode, the files.
71 Force replacement of output files if they exist.
72 If \-f is omitted and toast (or untoast) is run interactively from
73 a terminal, the user is prompted as to whether the file should be replaced.
77 Do not delete the source files.
78 Source files are implicitly left alone whenever \-c is
79 specified or tcat is run.
83 Ignore most sample values when calculating the GSM long-term
84 correlation lag during encoding.
85 (The multiplications that do this are a bottleneck
87 The resulting encoding process will not produce
88 exactly the same results as GSM 06.10 would,
89 but remains close enough to be compatible.
93 option applies only to the encoder and is silently
94 ignored by the decoder.
98 On systems with a floating point processor, but without
99 a multiplication instruction, \-F sacrifices standard conformance to
100 performance and nearly doubles the speed of the algorithm.
102 The resulting encoding and decoding process will not produce
103 exactly the same results as GSM 06.10 would, but remains close
104 enough to be compatible.
106 The default is standard-conforming operation.
110 outputs the version of toast (or untoast or tcat) to stdout and exits.
114 prints a short overview of the options.
116 Toast, untoast and tcat try to guess the appropriate audio data
117 format from the file suffix.
118 Command line options can also specify a format to be used for
121 The following formats are supported:
125 8 kHz, 8 bit \(*mU-law encoding (file suffix .u)
129 8 kHz, 8 bit A-law encoding (file suffix .A)
133 8 kHz, 8 bit \(*mU-law encoding with audio header (file suffix .au)
137 8 kHz, 16 bit signed linear encoding in host byte order
138 with 13 significant bits (file suffix .l)
140 In absence of options or suffixes to specify a format,
141 \(*mU-law encoding as forced by \-u is assumed.
144 A four bit magic number is prefixed to each 32 1/2-byte GSM frame,
145 mainly because 32 1/2-bytes are rather clumsy to handle.
147 The compression algorithm used is a lossy compression algorithm
148 devised especially for speech; on no account should it be used
149 for text, pictures or any other non-speech-data you consider
152 Please direct bug reports to jutta@cs.tu-berlin.de.
156 .\" Toast is dedicated to Bill Sienkiewicz, author of "Stray Toasters".