IFF

• Extensions: 8svx, 16sv, ilbm, anim
• MIME Types:
  • 8svx: audio/8svx, audio/x-8svx
  • 16sv: audio/16sv, audio/x-16sv
  • ilbm: image/ilbm, image/x-ilbm
  • anim: video/anim, video/x-anim
• Specification:
  • Original Electronic Arts specification january 14 1985.

IFF (Interchange File Format) is a format developed by electronic arts in the 80's. It is the predominant format on the Amiga computer. It is a chunked format. It can be used to store any type of data, but it is predominantly used to store images, animations and audio.

Implementations

• xine has a demuxer/decoder for iff. Manfred Tremmel the author of the xine code has agreed to relicence his xine code as LGPL to allow easier use in ffmpeg. Thanks Manfred.
• Werner Randelshofer the author of multishow has also granted permission for his iff code to be relicenced as LGPL. Thanks Werner.
• Xanim also contains code to support iff, it may contain some formats not available in xine.
• libiffanim supports lots of animation formats http://www-user.tu-chemnitz.de/~womar/projects/iffanim/
• Virtualdub contains a demuxer/decoder also, look in the file InputFileANIM.cpp

Generic Chunk Format

typedef struct {
    char FOURCC[4];
    int32_t chunk_size;
    uint8_t data[size];
} IFF_chunk;

IFF chunks are always padded to an even number of bytes. The possible padding byte is not included in chunk_size.

Example of a chunked IFF file:

FORM ILBM BMHD CMAP BODY

Table Of Chunks

Note: FOURCC's of less than four characters are padded with spaces.

Group Identifiers
FOURCC	Standard	Description
CAT	EA85
END	unofficial	END-of-FORM identifier (see Amiga RKM Devices Ed. 3 page 376)
FORM	EA85
LIST	EA85
PROP	EA85
TREE		Storage of arbitrary data structures like trees and nested lists
Text, annotations, et cetera
FOURCC	Standard	Description
(c)	EA85	Copyright
ANNO	EA85	Annotation
AUTH	EA85	Author
CHRS	EA85	Character String
CSET		Character Set
FTXT	EA85	Formatted Text
FVER		Amiga OS Version String
HLID	private	HotLink IDentification (Soft-Logik)
JUNK		Ignore
NAME	EA85	Title of image, music, ...
OCMP	EA85, reserved	Computer Property
OCPU	EA85, reserved	CPU Property
OPGM	EA85, reserved	Program Property
OSN	EA85, reserved	Serial Number Property
PTXT	private, reserved
TEXT	EA85	Unformatted ASCII Text
UNAM	EA85, reserved	Username Property
VERS		File Version Number
Graphics Forms
FOURCC	Standard	Description
ACBM		Amiga Contiguous Bitmap (AmigaBasic)
CHBM	private	Chunky Bitmap
DCCL	private	DCTV Paint Clip
DCPA	private	DCTV Paint Palette
DCTV	private	DCTV Raw Picture
DEEP		Chunky Pixel Image Files (TV Paint)
DR2D		2D Object, Vector Graphics
DRAW	reserved	Jim Bayless, 12/90
DSDR	private	DrawStudio
GRYP	proposal	Byteplane Storage
ILBM	EA85	Raster Bitmap Form
ILBM.*		See ILBM Chunks below
OB3D	proposal	3D Object
PBM		256-Color Chunky Pixel
PICS	EA85, reserved	Macintosh Picture
PICS.PICT	EA85, reserved	Macintosh Picture
PLBM	EA85, reserved	Obsolete
RGB4	private	4-bit RGB
RGB8		RGB Image, Turbo Silver (Impulse)
RGBN		RGB Image, Turbo Silver (Impulse)
RGBX	private, reserved
SC3D	private	3D Scene, Sculpt-3D
TDDD		3D Rendering Data, Turbo Silver (Impulse)
YUVN		YUV Image Data, MacroSystems
ILBM Chunks
FOURCC	Standard	Description
3DCM	reserved	by Haitex
3DPA	reserved	by Haitex
ABIT		ACBM Body
ASDG	private	ASDG Application
BHBA	private	Photon Paint (brushes)
BHCP	private	Photon Paint (screens)
BHSM	private	Photon Paint
BMHD	EA85	ILBM Bitmap Header
BODY	EA85	Image Data
CAMG		Amiga Viewport Modes
CCRT		Graphicraft Color Cycling
CLUT		Color Lookup Table
CMAP	EA85	8-bit RGB Color Map (packed array of ColorRegisters)
CMYK		CMYK Color Map (Soft-Logik)
CNAM		Color Naming Chunk, providex names for CMAP and/or CMYK (Soft-Logik)
CRNG		Color Cycling
CTBL.DYCP		Newtek Dynamic Ham Color
DCOL	unofficial	Direct Color
DCTV	reserved
DEST		Destination Image Info
DGVW	private	Newtek DigiView
DLTA		Image Data
DPI		Dots Per Inch
DPPV		DPaint Perspective (EA)
DRNG		DPaint IV Enhanced Color Cycling (EA)
EPSF		Encapsulated Postscript
FAX3	private	GPSoftware FAX
FAXX		Fascimile Image
FAXX.GPHD		Additional Header Info for FAXX forms
GRAB		Hotspot Coordinates
MFAX	private, reserved	TKR GmbH & Co.
PCHG		Line-by-line Palette Control Information
PRVW	proposal	Preview (thumbnail)
SHAM		Sliced HAM Color
SPRT		Sprite Identifier
TMAP	reserved	Transparency Map
VTAG	proposal	Viewmode Tags
XBMI		Extended Bitmap Information (Soft-Logik)
XSSL		Identifier for 3D X-Specs Image (Haitex)
Audio and Music
FOURCC	Standard	Description
16SV
8SVX	EA85	8-bit Sound Sample
8SVX.VHDR		Voice Header
8SVX.CHAN.PAN		Stereo chunks
8SVX.SEQN.FADE		Looping chunks
AHIM	private	AHI Modes
AHIM.AUDN	private	Audio Driver Name
AHIM.AUDD	private	Audio Driver Data
AHIM.AUDM	private	Audio Mode
AIFF		Audio 1-32 bit Samples
BANK	private	Soundquest Editor/Librarian MIDI Sysex Dump
CELP	proposal	Compressed ZyXEL Voice Data
CMUS	proposal	Common Musical Score
GSCR	EA85	General Music Score
MIDI	private	Circum Design
MSCX	private	Music-X Format
SAMP		Sampled Sound
SYTH	private	SoundQuest Master Librarian MIDI System Driver
TRKR	proposal	MOD Tracker Music
USCR	EA85, reserved	Uhuru Score
UVOX	EA85, reserved	Uhuru Mac Voice
Fonts
FOURCC	Standard	Description
CPFM	private	Cloanto Personal Fontmaker
FNTR	EA85, reserved	Raster Font
FNTV	EA85, reserved	Vector Font
Animation and Movies
FOURCC	Standard	Description
AHAM	private
ANBM		Animated Bitmap (Framer, Deluxe Video)
ANHD		ANIM Frame
ANIM		Cel Animation
ANIM.brush		Brushes
ANIM.op6		Stereo, 3D Animation
ANIM.op7	private, unregistered
ANIM.op8
DPAN		Deluxe Paint Animation
FANT		Fantavision Movie
FIGR	private	Deluxe Video
FILM	private	Store ILBM's with interleaved 8SVX audio
JMOV	private, reserved	Merging Technologies
MOVI	private	LIST MOVI
ROXN	private
VDEO	private	Deluxe Video
YAFA	private, unregistered	Wildfire Animation
Unclassified, unknown, et cetera
FOURCC	Standard	Description
ANFI
ANSQ
ARC	proposal	Archive Format
ARES	private, unregistered
ATXT	reserved
ATAK
AVCF	private	AmigaVision Flow format
BBSD	private	BBS Database, F. Patnaude, Jr., Phalanx Software
C100	private	Cloanto Italiaformat
CLIP	private	CAT CLIP, holds various clipboard formats
DECK	private	Inovatronics CanDo
DOC	private	PageStream
DPPS
DTYP		DataTypes Identification
EXEC	proposal	Executable Code
FACE
FRED	private	ASDG Global Chunk
GMS		Gesture and Motion Signal (see libGMS)
GUI	proposal, private	Graphical User Interface Storage
HEAD		Flow Idea Processor, New Horizons Software
IMRT
INFO	proposal	Contains data usually found in .info file
INS1
IOBJ	private, reserved	Seven Seas Software
IODK	private, reserved	Jean-Marc Porchet, Merging Technologies
ITRF	private, reserved
MHDR
MSMP	reserved
MTRX		Numerical Data Storage, MathVision - Seven Seas
NSEQ	private	Numerical Sequence, Stockhausen GmbH
PGTB		Program Traceback (SAS Institute)
PMBC	proposal, reserved	Black Belt System, 1991-12-01
PREF	private, reserved	Commodore, User Preferences
PREF.AHI	private	AHI Global Preferences
PREF.AHIU	private	AHI Unit Preferences
PRSP		DPaint IV Perspective Move
PTCH	private	Patch File, SAS Institute
RLSE
SHAK	private	Shakespeare Format
SHDR
SHO1	private, reserved	Gary Bonham
SHOW	private, reserved	Gary Bonham
SPLT		ASDG's File Splitting System
SSRE	private, reserved	Merging Technologies, 1992-05-04
SWRT	private, unregistered
TCDE	private, reserved	Merging Technologies
TERM	private, unregistered
TINY
TMUI		Toolmaker IFF Project (Toolmaker v1.19)
TRAK
WORD		ProWrite Document, New Horizons
WOWO	private, unregistered	Wordworth

Chunks Internals

Described below is how the data part of specific chunks are to be interpreted.

BMHD

Images are stored in planes. So, to get a pixels color value you need to combine the bits from each plane to create a color register index.

typedef struct {
 uint16_t w;                    /* raster width in pixels */
 uint16_t h;                    /* raster height in pixels */
 int16_t  x;                    /* x offset in pixels */
 int16_t  y;                    /* y offset in pixels */
 uint8_t  nplanes;              /* # source bitplanes */
 uint8_t  masking;              /* masking technique, 0 = mskNone, 1 = mskHasMask, 2 = mskHasTransparentColor, 3 = mskLasso */
 uint8_t  compression;          /* compression algoithm, 0 = cmpNone, 1 = cmpByteRun1 */
 uint8_t  pad1;                 /* UNUSED.  For consistency, put 0 here. */
 uint16_t transparentColor;     /* transparent "color number" */
 uint8_t  xaspect;              /* aspect ratio, a rational number x/y */
 uint8_t  yaspect;              /* aspect ratio, a rational number x/y */
 int16_t  pagewidth;            /* source "page" size in pixels */
 int16_t  pageheight;           /* source "page" size in pixels */
} BitMapHeader;

BODY

The BODY's content is a concatenation of scanlines. Each scanline consists of one row of data for each plane, starting at plane 0, followed by one row of masking data (if BMHD.maskinh = mskHasMask). If BMHD.compression = cmpNone, all h rows are exactly ceil(w/16) uint16_t's wide.

ByteRun1 Algorithm

   0 <= x <= 127  x+1 literals
-127 <= x <= -1   -x+1 times next byte
-128              unused

Each row of each scanline is compressed separately.

CAMG

typedef int32_t viewportMode;

CMAP

typedef struct {
 struct {
  uint8_t red;
  uint8_t green;
  uint8_t blue;
 } colormap[chunk_size / 3];
} ColorMap;

CCRT

typedef struct {
 int16_t direction;     /* 0 = none, >0 = forwards, <0 = backwards */
 uint8_t start;         /* lower... */
 uint8_t end;           /* ...and upper color registers */
 int32_t seconds;       /* seconds between cycles */
 int32_t microseconds;  /* microseconds between cycles */
 int16_t pad;           /* 0 */
} CycleInfo;

CRNG

typedef struct {
 int16_t pad1;        /* 0 */
 int16_t rate;        /* color cycle rate, 16384 = 60Hz */
 int16_t active;      /* 0 = off, >0 = on */
 uint8_t low;         /* lower... */
 uint8_t high;        /* ...and upper color registers */
} CRange;

DEST

typedef struct {
 uint8_t  depth;           /* # bitplanes in the original source */
 uint8_t  pad1;            /* 0 */
 uint16_t planePick;       /* how to scatter source bitplanes into destination */
 uint16_t planeOnOff;      /* default bitplane data for planePick */
 uint16_t planeMask;       /* which bitplanes to store into
} DestMerge;

GRAB

Hotspot, relative to the upper left corner. Think mouse cursor or paint brush.

typedef struct {
 int16_t x;
 int16_t y;
} Point2D;

SPRT

typedef uint16_t SpritePrecedence; /* relative precedence; 0 is highest */

VHDR

A Voice holds waveform data for one or more octaves. The one-shot part is played once and the repeat part is looped. The sum of oneShotHiSamples and repeatHiSamples is the full length of the highest octave sample. Each following sample is twice as long as the previous one.

typedef struct {
 uint32_t oneShotHiSamples;       /* length of highest octave one-short part */
 uint32_t repeatHiSamples;        /* length of highest octave repeat part */
 uint32_t samplesPerHiCycle;      /* frequency */
 uint16_t samplesPerSec;          /* samplerate */
 uint8_t  ctOctave;               /* number of octaves of waveforms */
 uint8_t  sCompression;           /* 0 = none, 1 = Fibonacci Delta Encoding */
 int32_t  volume;                 /* 0 = silent, 0x10000 = max */
} Voice8Header;