Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame] | 1 | .\" |
| 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. |
| 5 | .\" |
| 6 | .if n .ds mU u |
| 7 | .if t .ds mU \(*m |
| 8 | .\" |
| 9 | .TH TOAST 1 local |
| 10 | .SH NAME |
| 11 | toast \(em GSM\ 06.10 lossy sound compression |
| 12 | .SH SYNOPSIS |
| 13 | .ll +8 |
| 14 | .B toast |
| 15 | [ |
| 16 | .B \-cdfpvhualsFC |
| 17 | ] [ |
| 18 | .I "filename...\&" |
| 19 | ] |
| 20 | .LP |
| 21 | .B untoast |
| 22 | [ |
| 23 | .B \-cfpvhuaslF |
| 24 | ] [ |
| 25 | .I "filename...\&" |
| 26 | ] |
| 27 | .LP |
| 28 | .B tcat |
| 29 | [ |
| 30 | .B \-vhuaslF |
| 31 | ] [ |
| 32 | .I "filename...\&" |
| 33 | ] |
| 34 | .ll -8 |
| 35 | .SH DESCRIPTION |
| 36 | Toast compresses the sound files given on its command line. |
| 37 | Each file is replaced by a file with the extension |
| 38 | .I \&.gsm . |
| 39 | If no files are specified, the compression is applied to the |
| 40 | standard input, and its result is written to standard output. |
| 41 | .PP |
| 42 | Toasted files can be restored to something not quite unlike |
| 43 | their original form by running toast |
| 44 | .I "\-d" |
| 45 | , or |
| 46 | .I untoast |
| 47 | , on the \&.gsm-files or standard input. |
| 48 | .PP |
| 49 | The program |
| 50 | .I tcat |
| 51 | (the same as running |
| 52 | .I "untoast \-c" |
| 53 | ) uncompresses its input on standard output, |
| 54 | but leaves the compressed .gsm\-files alone. |
| 55 | .PP |
| 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. |
| 59 | .SH OPTIONS |
| 60 | .TP |
| 61 | .B \-c |
| 62 | (cat) |
| 63 | Write to the standard output; no files are changed. |
| 64 | .TP |
| 65 | .B \-d |
| 66 | (decode) |
| 67 | Decode, rather than encode, the files. |
| 68 | .TP |
| 69 | .B \-f |
| 70 | (force) |
| 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. |
| 74 | .TP |
| 75 | .B \-p |
| 76 | (precious) |
| 77 | Do not delete the source files. |
| 78 | Source files are implicitly left alone whenever \-c is |
| 79 | specified or tcat is run. |
| 80 | .TP |
| 81 | .B \-C |
| 82 | (LTP cut-off) |
| 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 |
| 86 | of the algorithm.) |
| 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. |
| 90 | .br |
| 91 | The |
| 92 | .B \-C |
| 93 | option applies only to the encoder and is silently |
| 94 | ignored by the decoder. |
| 95 | .TP |
| 96 | .B \-F |
| 97 | (fast) |
| 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. |
| 101 | .br |
| 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. |
| 105 | .br |
| 106 | The default is standard-conforming operation. |
| 107 | .TP |
| 108 | .B \-v |
| 109 | (version)\ |
| 110 | outputs the version of toast (or untoast or tcat) to stdout and exits. |
| 111 | .TP |
| 112 | .B \-h |
| 113 | (help)\ |
| 114 | prints a short overview of the options. |
| 115 | .PP |
| 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 |
| 119 | all files. |
| 120 | .br |
| 121 | The following formats are supported: |
| 122 | .TP |
| 123 | .B "\-u" |
| 124 | (\(*mU-law) |
| 125 | 8 kHz, 8 bit \(*mU-law encoding (file suffix .u) |
| 126 | .TP |
| 127 | .B "\-a" |
| 128 | (A-law) |
| 129 | 8 kHz, 8 bit A-law encoding (file suffix .A) |
| 130 | .TP |
| 131 | .B "\-s" |
| 132 | (Sun audio) |
| 133 | 8 kHz, 8 bit \(*mU-law encoding with audio header (file suffix .au) |
| 134 | .TP |
| 135 | .B "-l" |
| 136 | (linear) |
| 137 | 8 kHz, 16 bit signed linear encoding in host byte order |
| 138 | with 13 significant bits (file suffix .l) |
| 139 | .PP |
| 140 | In absence of options or suffixes to specify a format, |
| 141 | \(*mU-law encoding as forced by \-u is assumed. |
| 142 | .PP |
| 143 | .SH PECULIARITIES |
| 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. |
| 146 | .SH WARNING |
| 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 |
| 150 | valuable. |
| 151 | .SH BUGS |
| 152 | Please direct bug reports to jutta@cs.tu-berlin.de. |
| 153 | .SH "SEE ALSO" |
| 154 | gsm(3) |
| 155 | .\" |
| 156 | .\" Toast is dedicated to Bill Sienkiewicz, author of "Stray Toasters". |