aiff(4)								       aiff(4)

NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/audiofile.h>

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     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:





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aiff(4)								       aiff(4)



     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    [Toc]    [Back]

     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    [Toc]    [Back]

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


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