InfoAudio

Routine

InfoAudio [options] AFile1 [AFile2 ... ]

Purpose

Print audio file information

Description

This program prints information about a number of audio files to standard output. The information about the internal structure of the files is in a form that can be easily parsed by a shell script.

The full output consists of the file type and name (indented part of the output below), the file data parameters, and the header information records.

   AFsp audio file: /usr/local/src/audio/InfoAudio/test/xx.au
     Number of samples : 23808  1994/02/04 14:12:50 UTC
     Sampling frequency: 8000 Hz
     Number of channels: 1 (16-bit integer)
  File name: xx.au
  Header length: 104
  Sampling frequency: 8000
  No. samples: 23808
  No. channels: 1
  Data type: integer16         - mu-law8, integer16 or float32
  File byte order: big-endian  - big-endian, little-endian, or byte-stream 
  Host byte order: big-endian  - big-endian or little-endian
  --Header information records--
  date:1994/02/04 14:12:50 UTC
  user:library@aldebaran
  program:CopyAudio

For single byte data, the "File byte order" field is set to "byte-stream".

Non-printing characters (as defined by the routine isprint) in the header information records are replaced by question marks.

Options

The command line specifies options and the file name.

-P PARMS, --parameters=PARMS

Parameters to be used for headerless input files. This option may be given more than once. Each invokation applies to the files that follow the option. See the description of the environment variable RAWAUDIOFILE below for the format of the parameter specification.

-i ICODE, --info_code=ICODE

Parameter to choose the information to be printed. The information that can be printed consists of three parts. The ICODE parameter is the sum of the codes which control printing of the individual parts.

  1:  Print the file type and name
  2:  Print the file data parameters
  4:  Print the header information records

The default is to print all of the information (ICODE=7). For ICODE=0, no information is printed, but the program return code indicates if all files were opened successfully.

-h, --help

Print a list of options and exit.

-v, --version

Print the version number and exit.

Environment variables

RAWAUDIOFILE:

This environment variable defines the data format for headerless or non-standard input audio files. The string consists of a list of parameters separated by commas. The form of the list is

  "Format, Start, Sfreq, Swapb, Nchan, ScaleF"

Format: File data format

The lowercase versions of these format specifiers cause a headerless file to be accepted only after checking for standard file headers; the uppercase versions cause a headerless file to be accepted without checking the file header.

 "undefined"                - Headerless files will be rejected
 "mu-law8" or "MU-LAW8"     - 8-bit mu-law data
 "A-law8" or "A-LAW8"       - 8-bit A-law data
 "unsigned8" or "UNSIGNED8" - offset-binary 8-bit integer data
 "integer8" or "INTEGER8"   - two's-complement 8-bit integer data
 "integer16" or "INTEGER16" - two's-complement 16-bit integer data
 "float32" or "FLOAT32"     - 32-bit floating-point data
 "text" or "TEXT"           - text data

Start: byte offset to the start of data (integer value)

Sfreq: sampling frequency in Hz (floating point number)

Swapb: Data byte swap parameter

 "native" - no byte swapping
 "little-endian" - file data is in little-endian byte order
 "big-endian" - file data is in big-endian byte order
 "swap" - swap the data bytes as the data is read

Nchan: number of channels

The data consists of interleaved samples from Nchan channels

ScaleF: Scale factor

Scale factor applied to the data from the file

The default values for the audio file parameters correspond to the following string.

    "undefined, 0, 8000., native, 1, 1.0"

AUDIOPATH:

This environment variable specifies a list of directories to be searched when opening the input audio files. Directories in the list are separated by colons (semicolons for MS-DOS).

Author / version

P. Kabal / v2r2 1996/08/12