Routine

GenNoise [options] AFile

Purpose

Generate an audio file containing uncorrelated Gaussian noise samples

Description

This program generates zero-mean uncorrelated pseudo-random Gaussian deviates. These white noise samples are written to an audio file. Each invocation of this program generates a different random sequence. Options are available to specify the number of samples, the sampling frequency and the data format of the output file.

Options

Output file name: AFile:
Specifying "-" as the output file indicates that output is to be written to standard output. If the output file type is not explicitly given (-F option), the extension of the output file name is used to determine the file type.

  ".au"   - AU audio file
  ".wav"  - WAVE file
  ".aif"  - AIFF sound file
  ".afc"  - AIFF-C sound file
  ".raw"  - Headerless file (native byte order)
  ".txt"  - Headerless file (text data)

-d SDEV, --std_deviation=SDEV
Standard deviation of the noise samples in normalized units, default 0.03. The standard deviation can be given as a real number (e.g., "0.03") or as a ratio (e.g., "983.04/32768"). -x SEED, --seed=SEED
Seed for the random number generator, default from current time. -n NSAMPLE, --number_samples=NSAMPLE
Number of output samples to be generated. -s SFREQ, --srate=SFREQ
Sampling frequency for the output audio file, default 8000. -F FTYPE, --file_type=FTYPE
Output file type. If this option is not specified, the file type is determined by the output file name extension.

  "AU" or "au"             - AU audio file
  "WAVE" or "wave"         - WAVE file
  "WAVE-NOEX" or "wave-noex" - WAVE file (no extensible data)
  "AIFF-C" "aiff-c"        - AIFF-C sound file
  "AIFF" or "aiff"         - AIFF sound file
  "noheader" or "noheader_native" - Headerless file (native byte
                             order)
  "noheader_swap"          - Headerless file (byte swapped)
  "noheader_big-endian"    - Headerless file (big-endian byte
                             order)
  "noheader_little-endian" - Headerless file (little-endian byte
                             order)

-D DFORMAT, --data_format=DFORMAT
Data format for the output file, default integer16

  "mu-law8"   - 8-bit mu-law data
  "A-law8"    - 8-bit A-law data
  "unsigned8" - offset-binary 8-bit integer data
  "integer8"  - two's-complement 8-bit integer data
  "integer16" - two's-complement 16-bit integer data
  "integer24" - two's-complement 24-bit integer data
  "integer32" - two's-complement 32-bit integer data
  "float32"   - 32-bit floating-point data
  "float64"   - 64-bit floating-point data
  "text"      - text data

The data formats available depend on the output file type. AU audio files:

  mu-law, A-law, 8/16/24/32-bit integer, 32/64-bit float

WAVE files:

  mu-law, A-law, offset-binary 8-bit integer, 16/24/32-bit integer,
  32/64-bit float

AIFF-C sound files:

  mu-law, A-law, 8/16/24/32-bit integer, 32/64-bit float

AIFF sound files:

  8/16/24/32-bit integer

Headerless files:

  all data formats

-I INFO, --info=INFO
Audio file information string for the output file. -h, --help
Print a list of options and exit. -v, --version
Print the version number and exit.

By default, the output file contains a standard audio file information string.

  Standard Audio File Information:
     date: 1994-01-25 19:19:39 UTC    date
     program: GenNoise                program name

This information can be changed with the header information string which is specified as one of the command line options. Structured information records should adhere to the above format with a named field terminated by a colon, followed by numeric data or text. Comments can follow as unstructured information.

  Record delimiter: Newline character or the two character escape
      sequence "\" + "n".
  Line delimiter: Within records, lines are delimiteded by a carriage
      control character, the two character escape sequence "\" + "r",
      or the two character sequence "\" + newline.

If the information string starts with a record delimiter, the header information string is appended to the standard header information. If not, the user supplied header information string appears alone.

Author / version

P. Kabal / v5r0a 2003-11-06

Routine

Purpose

Description

Options

Author / version

See Also