1TOAST(1) General Commands Manual TOAST(1)
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6 toast — GSM 06.10 lossy sound compression
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9 toast [ -cdfpvhualsFC ] [ filename... ]
10 untoast [ -cfpvhuaslF ] [ filename... ]
12 tcat [ -vhuaslF ] [ filename... ]
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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.
20 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.
24 The program tcat (the same as running untoast -c ) uncompresses its
26 input on standard output, but leaves the compressed .gsm-files alone.
27 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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33 -c (cat) Write to the standard output; no files are changed.
34 -d (decode) Decode, rather than encode, the files.
36 -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.
41 -p (precious) Do not delete the source files. Source files are
43 implicitly left alone whenever -c is specified or tcat is run.
44 -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.
52 -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.
60 -v (version) outputs the version of toast (or untoast or tcat) to
62 stdout and exits.
63 -h (help) prints a short overview of the options.
65 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:
70 -u (μU-law) 8 kHz, 8 bit μU-law encoding (file suffix .u)
72 -a (A-law) 8 kHz, 8 bit A-law encoding (file suffix .A)
74 -s (Sun audio) 8 kHz, 8 bit μU-law encoding with audio header (file
76 suffix .au)
77 -l (linear) 8 kHz, 16 bit signed linear encoding in host byte order
79 with 13 significant bits (file suffix .l)
80 In absence of options or suffixes to specify a format, μU-law encoding
82 as forced by -u is assumed.
83
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.
87
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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94 Please direct bug reports to jutta@cs.tu-berlin.de.
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97 gsm(3)
98 local TOAST(1)