MOVIE! a ram animation system
 
                                   by
 
                               Eric Graham
 
                              Version 1.00
 
 
 
The MOVIE! ram animation system consists of three programs that must be
run from CLI.  You will need to be familiar with CLI and with the use of
a text editor, such as ED, because you will need to write text files to
control the animation.  The three programs are:
 
        DILBM   Calculates the difference between two image files.
        PILBM   Packs several difference files into a single animation
                file.
        MOVIE   Plays back the animation.
 
This system differs from other similar programs in several important
ways:
 
    1) It is in the public domain.  It may be freely copied and
distributed for non commercial purposes.  Upgrades and enhancements may
be provided from time to time.
 
    2) It employs J-type animation compression.  This is an adaptive
algorithm that employs numerous different strategies to achieve the best
compression and fastest playback.  Additional strategies will probably
be added to improve performance still further.
 
    3) It works with HAM and non-HAM images, either full screen or
overscan.  It also works with European PAL Amigas.
 
 
 
DILBM
-----
 
This program calculates the differences between two images and stores
the result as a delta file.  The program is called with the names of
three files:
 
        dilbm image1 image2 delta
 
The two image files must exist.  The delta file will be created.  The
delta file represents the data required to convert image1 into image2.
It is not reversible.
 
There is an alternate delta format that is reversible, to generate it,
add an 'x' at the end of the command:
 
        dilbm image1 image2 delta x
 
Normally, dilbm will display a picture of the differences between the
images.  To suppress this picture, add a 'q' at the end of the command,
this will make dilbm run slightly faster.
 
 
PILBM
-----
 
This program packs delta files together to create an animation.  It
takes a single argument that is the name of a text file that contains a
description of the animation.  The following format must be followed:
 
        line
          1     a     The name of the animation that is to be produced.
          2     i     The name of the initial image.
          3     d0    The name of the initial delta file.
          4     d1    The name of the first delta file.
          5     d2    The name of the second delta file.
          ...
          n+3   dn    The name of the last delta file.
          n+4   *     An asterisk to denote the start of sequence control
          n+5   m t   m is a delta number and t is a time delay
          n+6   m t
          ...
                m t
 
The animation works by double buffering, so you must specify two images.
The file 'i' specifies the first image.  The delta file 'd0' defines the
second image in terms of the first.
 
The delta file 'd0' is discarded after the second image file is
constructed.  The remaining delta files, d1 to dn are stored in memory.
When the animation is replayed, the following actions take place:
 
The first image is displayed on the screen.  Then the second image is
displayed.  While the second image is displayed, the first image is
changed with a delta file.  Then it is displayed while the second image
is modified with another delta file.  This process is repeated.
 
The sequence control determines the order in which the delta files are
used.  The value 'm' determines which delta file is to be used.  The
value t specifies how much time (in jiffies) is to be used for the
change.  If t is negative, then m is used to indicate a transfer to the
m'th m-t pair.  Thus the following sequence
 
                *
                3  2
                5  2
                9  2
                12 2
                2  -1
 
would stand for the following sequence of delta files:
 
        d3 d5 d9 d12 d5 d9 d12 d5 d9 d12 d5 d9 d12 etc.
 
Not all delta files need to be used (although that would be wasteful)
and some may be used many times, if the sequence control specifies a
loop.
 
Deciding which images to use to construct delta files, and the correct
sequence of delta files is complicated because of the nature of double
buffering.  Here is an example, suppose that we wish to display images
in the following sequence:
 
        15 14 13 12 11 10 9 8 7 8 9 10 11 12 13 14 15 14 13 12 11 etc
 
then we can use the 'x' type of reversible deltas and compute the
following files (it is a good idea to place the dilbm commands in a text
file and use an 'execute' command).
 
dilbm  pic15.image pic14.image dx15-14 x q
dilbm  pic15.image pic13.image dx15-13 x q
dilbm  pic14.image pic12.image dx14-12 x q
dilbm  pic13.image pic11.image dx13-11 x q
dilbm  pic12.image pic10.image dx12-10 x q
dilbm  pic11.image pic9.image  dx11-9  x q
dilbm  pic10.image pic8.image  dx10-8  x q
dilbm  pic9.image pic7.image   dx9-7   x q
dilbm  pic8.image pic8.image   dx8-8   x q
pilbm  buildx.script
 
The file buildx.script contains the following:
 
 
picx.anim
phongm15.image
dx15-14
 
dx15-13
dx14-12
dx13-11
dx12-10
dx11-9
dx10-8
dx9-7
dx8-8
*
1 2
2 2
3 2
4 2
5 2
6 2
7 2
8 2
7 2
6 2
5 2
4 2
3 2
2 2
1 2
8 2
1 -1
 
 
Note that the delta file dx8-8 causes no action to take place, so it is
also used in place of dx14-14.
 
 
MOVIE
-----
 
The movie playback program is particularly simple.  Give it the name of
an animation file.  Press the 'escape' key to stop an animation that is
looping.
 
The program may also be run from workbench, set the default tool of the
project (the animation file) to be 'movie'.  Alternatively, hold down
the shift key and click on the project and then while still holding
down the shift key, double click on the movie icon.