aiff(4)                                                                aiff(4)


NAME
     aiff, aiff-c, aifc - Audio Interchange File Format

SYNOPSIS
     #include <dmedia/audiofile.h>

DESCRIPTION
     The Audio File Library currently supports 13 of the commonly found audio
     file formats, i.e., is able to recognize, read, and write sample data and
     header information to and from files in these formats.  It is important
     not to confuse sample or audio data formats with file formats.  The
     former refers to the bit-wise organization of the sound samples in the
     file, i.e., whether the format is 8-bit integer or 16-bit unsigned, etc.
     Audio file format refers to the structure of the audio file header, the
     chunk of on-disk data which preceeds the samples and which provides
     information about the file to the audio program.  A single audio file
     format may support a large variety of sample formats.

     The Audio Interchange File Format (AIFF) was created by Apple Computer,
     Inc., in order to create a format for digital sound which conformed to
     the "EA IFF 85" Standard for Interchange Format Files developed by
     Electronic Arts.  It consists of a variable-length header followed by a
     contiguous block of binary data representing the sound samples.

DATA FORMAT SPECIFICATIONS
     Sample Formats:
          Two's complement integer data only

     Sample Widths:
          From 1 to 32 bits, inclusive

     Byte Orders:
          Always bigendian

     Channel Counts:
          Any nonzero number

     Compression Formats:
          The Extended Audio Interchange File Format (AIFF-C), also designed
          by Apple Computer, Inc., is based on the the Audio IFF format (see
          above).  In addition to the above specifications, the AIFF-C format
          supports a variety of compressed data formats.  These are all
          described in the afGetCompression(3dm) man page.  Currently, every
          compression scheme supported by the Audio File Library is also
          supported by the AIFF-C format with the exception of IMA DVI ADPCM
          compression (WAVE format only).

FILE FORMAT SPECIFICATIONS
     AIFF and AIFF-C files can contain a large number of additional chunks of
     data.  Most of these are parsed by the AF and made available:


     Instrument Configurations:
          Maximum of 1 allowed;  may be 0.  Either 0 or 2 loops are allowed.
          Instparams associated with this inst:


          AF_INST_MIDI_BASENOTE
          AF_INST_NUMCENTS_DETUNE
          AF_INST_MIDI_LONOTE
          AF_INST_MIDI_HINOTE
          AF_INST_MIDI_LOVELOCITY
          AF_INST_MIDI_HIVELOCITY
          AF_INST_NUMDBS_GAIN
          AF_INST_SUSLOOPID
          AF_INST_RELLOOPID

     See afSetInstParamLong(3dm) for more information about these parameters.

     Markers:
          From 0 to 65535 marker structs allowed

     Miscellaneous Chunks:

          AF_MISC_COPY            copyright string

          AF_MISC_AUTH            author string

          AF_MISC_NAME            name string

          AF_MISC_ANNO            annotation string

          AF_MISC_MIDI            MIDI system exclusive data

          AF_MISC_APPL            application-specific data

CAVEATS
     The AIFF-C compression formats which are supported by the Audio File
     Library are currently not supported by software which runs on Apple
     Computer, Inc.  machines.  To make an AIFF-C file portable, it is best to
     save it in uncompressed format as an AIFF file.

SEE ALSO
     afInitFileFormat(3dm), afGetFileFormat(3dm), afIntro(3dm),
     afInitCompression(3dm), afGetCompression(3dm)


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