AFopenWrite(3tsp)

Routine
AFILE *AFopenWrite (const char Fname[], int Fformat, long int Nchan, double Sfreq, FILE *fpinfo)

Purpose
Open an audio file for writing

Description
This routine opens an audio file for writing. This routine sets up the audio file parameters to write data of the given format to the audio file. After writing data to the file, the routine AFclose should be called to update the file header information and close the file.

By default, information consisting of the date, the user and the program creating the file is written to the audio file header. The routine AFsetHInfo can be called before calling this routine to specify additional information to be written to the header. Any such additional header information is reset to null after being written to the header.

This routine can write AU audio files, AIFF-C files, RIFF WAVE files, and headerless audio files.

AU audio file:
8-bit mu-law, 8-bit A-law, 8-bit integer, 16-bit integer, 24-bit integer, 32-bit integer, and 32-bit IEEE floating-point, and 64-bit IEEE floating-point data formats are supported.
RIFF WAVE file:
8-bit mu-law, 8-bit A-law, offset-binary 8-bit integer, and 16-bit integer, 24-bit integer, 32-bit integer, 32-bit IEEE floating-point, and 64-bit IEEE floating-pont data formats are supported.
AIFF-C file:
8-bit mu-law, 8-bit A-law, 8-bit integer, 16-bit integer, 24-bit integer, and 32-bit integer, 32-bit IEEE floating-point, and 64-bit IEEE floating-point data formats are supported.
Headerless file:
8-bit mu-law, 8-bit A-law, offset-binary 8-bit integer, 8-bit integer, 16-bit integer, 24-bit integer, 32-bit integer, and 32-bit floating-point, 64-bit floating-point, and text data formats are supported. A text format file has the data in character form, one value to a line.

For the fixed point file data representations, input values in the following ranges will be converted without clipping.
   data format       allowed values
  8-bit mu-law   - [ -32636, +32636 ]
  8-bit A-law    - [ -32768, +32768 ]
  8-bit integer  - [ -16384, -16383 ]
  16-bit integer - [ -32768, +32767 ]
  24-bit integer - [ -32768, +32768 )
  32-bit integer - [ -32768, +32768 )
For AU and WAVE files containing floating-point data, values are scaled by 1/32768 before being written to the file. For data values between [-32768, +32768], the file data will lie in the range [-1, +1]. For headerless files of any data format, the values are written scaled by unity.

Parameters
<- AFILE *AFopenWrite
Audio file pointer for the audio file
 -> const char Fname[]
Character string specifying the file name. The file name "-" means standard output.
 -> int Fformat
Audio file format code, evaluated as the sum of a data format code and a file type,
  Fformat = Dformat + 256 * Ftype
For Ftype equal to zero, the file will have the standard AU audio file header. The Ftype flag allows for other file types as described below. Note that not all data formats are allowed for all file types. Dformat: data format
  FD_MULAW8  = 1,  mu-law 8-bit data
  FD_ALAW8   = 2,  A-law 8-bit data
  FD_UINT8   = 3,  offset-binary 8-bit integer data
  FD_INT8    = 4,  two's-complement 8-bit integer data
  FD_INT16   = 5,  two's-complement 16-bit integer data
  FD_INT24   = 6,  two's-complement 24-bit integer data
  FD_INT32   = 7,  two's-complement 32-bit integer data
  FD_FLOAT32 = 8,  32-bit floating-point data
  FD_FLOAT64 = 9,  64-bit floating-point data
  FD_TEXT    = 10,  text data
Ftype: file type
  FTW_DEFAULT   = 0, default audio file type
  FTW_AU        = 1, AU audio file
  FTW_WAVE      = 2, RIFF WAVE file
  FTW_AIFF_C    = 3, AIFF-C audio file
  FTW_NH_EB     = 4, Headerless file (big-endian byte order)
  FTW_NH_EL     = 20, Headerless file (little-endian byte order)
  FTW_NH_NATIVE = 36, Headerless file (native byte order)
  FTW_NH_SWAP   = 52, Headerless file (byte-swapped byte order)
 -> long int Nchan
Number of channels
 -> double Sfreq
Sampling frequency
 -> FILE *fpinfo
File pointer for printing audio file information. If fpinfo is not NULL, information about the audio file is printed on the stream selected by fpinfo.

Author / revision
P. Kabal Copyright (C) 1999 / Revision 1.68 1999/06/14

See Also
AFclose, AFwriteData, AFsetHinfo, AFsp