HOWTO Make Movies out of PostScript Files

Marion Daalmeijer

June 5, 1998

Abstract

Contents

1.  Preparation of the Files

1.1  Name and Size of the Files

First of all you have to make a lot of PostScript files, which eventually will be the movie. Make sure they have all the same size. You can control the size by using the program XV. This program may also be used to change the format of a file.

The names of the files should be image.0000.ps, image.0001.ps, etc., where image may be any chosen name.

1.2  Format of the Files

Now it depends on which procedure you want to follow. To use makempeg or whirlgif you need gif-files and for the use of mpeg2encode you need ppm-files. To convert a lot of ps-files to gif-files and ppm-files you may use the following script:

#!/usr/bin/sh
for name in `ls *.ps`
do
   ps2gifppm -col $name
done

2.  Make the Movie

Now you are ready to make the movie. But first you have to make a choice about the format of that movie-file. Will it be GIF or MPG?

2.1  Make a GIF Movie

The command you need is whirlgif: a quick program that reads a series of gif files, and produces a single gif file composed of those images.

Usage:
whirlgif [-v] [-trans index] [-time delay] [-o outfile] [-loop]
         [-i incfile] file1 [-time delay] file2

options: -v              verbose mode
         -loop [count]   add the Netscape 'loop' extension.
         -time delay     inter-frame timing.
         -disp [method]  Set disposal method, see below
         -trans index    set the colormap index 'index' to be transparent
         -o outfile      write the results to 'outfile'
         -i incfile      read a list of names from 'incfile'

2.1.1 TIPS

If you don't specify an output file, the GIF will be sent to stdout. This is a good thing if you're using this in a CGI script, a very bad thing if you run this from a terminal and forget to redirect stdout.

The output file (if any) and -loop _MUST_ be specified before any gif images.

You can specify several delay statements on the command line to change the delay between images in the middle of an animation, e.g

whirlgif -time 5 a.gif b.gif c.gif -time 100 d.gif -time 5 e.gif f.gif

To read more information: click on the location:

whirlgif.doc

2.2  Make an MPEG Movie

You decided you want to make an mpeg movie. Still you have two choices on how to do that:

• use makempeg to generate an mpg-file out of the gif-files
• use mpeg2encode to generate an mpg-file out of the ppm-files

2.2.1 Use MAKEMPEG

The command:

makempeg -fs 1 -fi 1 -fe 20 -base image -ext gif

Explanation of the command:

Usage: makempeg [-fs start] [-fe end] [-fi increment] [-base basename]
                [-ext extension]

          fs = fe = fi = 1 
          base = image

2.2.2 Use MPEG2ENCODE

To use the mpeg2encode program you need the ppm-files and a parameter file, for example mpeg-1.par. You will find examples of parameter files in directory

/usr/local/talib/mpeg

• the name of the source files
• input picture format
• number of frames
• horizontal_size
• vertical_size

The horizontal and vertical sizes you can obtain by viewing the ppm-file with xv:

xv image.ppm

Now you are ready to give the following command:

mpeg2encode MPEG-1.par image.mpg

mpeg2enc.doc