Message-ID: <331D21B2.2715@eik.bme.hu>
Date: Wed, 05 Mar 1997 08:33:06 +0100
From: "DR. Andras Solyom" <solyom AT eik DOT bme DOT hu>
Reply-To: solyom AT eik DOT bme DOT hu
Organization: Technical University of Budapest
MIME-Version: 1.0
To: djgpp AT delorie DOT com
Subject: Re: fli/flc files..
References: <9702271202 DOT AA11514 AT syntegra DOT bt DOT co DOT uk>
	 <8waMLRALkeFzEw4B AT talula DOT demon DOT co DOT uk> <5f4vf7$m9s AT news DOT ox DOT ac DOT uk> <y7YTnCAZODHzEw5d AT jenkinsdavid DOT demon DOT co DOT uk>
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David Jenkins wrote:
> 
> In article <5f4vf7$m9s AT news DOT ox DOT ac DOT uk>, George Foot
> <gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk> writes
> >Or write a FLI reverser, i.e. make a routine which creates the animation
> >in reverse. In this way, to step back a frame you would display the
> >changes from the reversed file, and to step forward a frame you would
> >use the normal file. This could perhaps be done internally, in memory,
> >rather than on disk.
> >
> >It's just an idea - I don't know anything about FLI, so maybe it's not
> >possible.
> >
> How hard would it be to add an FLI writer function???
> 
The FLI file format is documented in the book 
Graphics File Formats, (1995 Windcrest) Chapter 29 FLI/FLIC Animation.
 Just a little information about it:

The FLI and FLC headers are 128 bytes long, with contents as shown in
Tables 1 and 2.
Table 1: FLI file header
-------------------------
Offset  Size   Name      Description
   0      4   Size       Integer, byte length of file
   4      2   "magic"    Magic number Hex AF11, FLI identifier
   6      2   Size       Number of frames in file; 4000 max
   8      2   Width      Screen width (320 pixels)
  10      2   Height     Screen height (200 pixels)
  12      2   none       blank
  14      2   Flags      Set to 0
  16      2   Speed      Number of video ticks per frame @ 70 ticks/sec
  18      4   Next       Set to 0
  22      4   Frit       Set to 0
  26    102   Expansion  All zeroes--for future expansion
Table 2: FLC file header
---------------------------
Offset  Size   Name         Description
   0      4   Size          Integer, byte length of file
   4      2   "magic"       Magic number Hex AF12, FLC identifier
   6      2   Size          Number of frames in file; 4000 max
   8      2   Width         Screen width (pixels)
  10      2   Height        Screen height (pixels)
  12      2   Bits/primary  8
  14      2   Flags3        Indicating file properly closed
  16      4   Speed         Milliseconds delay per frame
  20      4   unused        0
  22      4   Created       Creation date, MS-DOS format
  26      4   Creator       Serial # of Animator Pro program used to
                            create animation
                            If not Animator Pro, then ASCII "FLIB"
                            (hex 464C4942)
  30      4   Updated       Most recent update date, MS-DOS format
  34      4   Updater       Like Creator, but for most recent update
  38      2   AspectX       X portion of aspect ratio X:Y
  40      2   AspectY       Y portion of aspect ratio X:Y
  42     38   reserved      all zeroes
  80      4   Offset1       Offset from beginning of file to first frame
                            chunk
  84      4   Offset2       Offset to second frame chunk, used for
                            looping
  88     40   reserved      All zeroes

FLC files are generally found in the following resolutions: 320 x 200,
640 x 480, 800 x 600, 1280 x 1024.
In FLC files, a prefix chunk may follow. This data structure contains no
information useful for playback and may be omitted or skipped. Its
presence may be detected and the prefix skipped by reading the 16 bytes
following the file header. Normally, these next 16 bytes are a frame
header, as shown in Table 3. If a prefix is present, the first four
bytes give the prefix size in bytes (including the 16 bytes); the next
two bytes contain the code Hex F100.
Table 3: FLI/FLC frame header
-----------------------------
Offset  Size   Name     Description
  0      4    Size      Bytes in frame, including header (< 64K for FLI)
  4      2    ID        Hex F1FA, identifying this as a frame
  6      2    Chunks    Number of "chunks" in frame; 0 indicates
                        identical frame
  8      8    reserved  All zeroes
FLC files may sometimes have an ID code of Hex 00A1 in the header,
signifying that the frame does not contain pixel data, but other
Animator Pro data. Such a frame may be skipped by using the frame length
given by Size, the 4-byte integer preceding the ID code.
Chunks follow the frame header. Each starts with a chunk header. The
chunk header is outlined in Table 4.
Table 4: Chunk header
Offset  Size   Name       Description
0       4      Size       Bytes in chunk, including header
4       2      Type code  Type of chunk
Chunk types are given by Tables 29-5 and 29-6. FLC files will generally
use FLI_COLOR_256 instead of FLI_COLOR, and FLI_WORD_LCinstead of
FLI_LC.
Table 29-5: FLI Chunk codes & interpretation
Code    Name     Type of chunk indicated by code
 11   FLI_COLOR  Compressed data for 64-color palette
 12   FLI_LC     Line compressed (RLE pixel data)
 13   FLI_BLACK  Set whole screen to color 0 (appears in first frame
                 only)
 15    FLI_BRUN   Bytewise run-length compression--first frame only
 16    FLI_COPY   Uncompressed data (64K bytes)
Table 29-6: FLC Chunk codes & interpretation
Code    Name         Type of chunk indicated by code
  4   FLI_COLOR_256  Data for 8-bit/primary palette
  7   FLI_WORD_LC    2-byte RLE compressed pixel data
 11   FLI_COLOR      Data for 6-bit/primary palette
 12   FLI_LC         Line compressed (not generally used in FLC)
 13   FLI_BLACK      Set whole screen to color 0 (appears in first frame
                     only)
 15   FLI_BRUN       Bytewise run-length compression--first frame only
 16   FLI_COPY       Uncompressed data (64K bytes)
 18   FLI_PREVIEW    "Thumbnail" image data
Bear in mind that all chunks are preceded by the chunk header.

I hope I do not violate the copyright by enclosing this info...
				Andras