There are a number of different 'motion picture' formats on the various types of computer platforms. The Motion Pictures Experts Group (MPEG) was formed to define a standard. In this format, the file contains details of which elements of the picture change from frame to frame. Variation of picture quality allows some control over the size of the file.
MPEG players exist for various types of computer. Here is a sample.
Other motion-picture formats include QuickTime (QT) and Silicon Graphics Movie Format (which has a degree of compatibility with QT) and Cinemation (Macs).
Movies are useful for displaying conformational changes in proteins, protein-ligand docking, and for displaying trajectories of Molecular Dynamics and Monte Carlo simulations.
(Make sure you have your MPEG player configured as a helper application for your WWW browser. For Unix systems, the line in your .mailcap file is something like:
video/mpeg; xterm -T MPEG -e mpeg_play -dither 2x2 -loop %s |________| |_____________|____________|___________|_______| | | | | | MIME type starts an xterm executes doubles plays MPEG in a loop window titled software frame 'MPEG' ('mpeg_play' dimensions in this case)
The above assumes you are using the 'mpeg_play' program. This software uses the 'dither' and 'loop' parameters (and several others)- ignore them if you want.)
To create an MPEG, you first need to create a series of individual frames. The procedure by which you do this with molecular graphics software will depend on the package. It is possible with RasMol, for example.
You then need to use MPEG-encoding software such as Berkeley Multimedia Research Center's mpeg_encode. Refer to the MPEG references in the list of URLs which accompanies this Section of the course.
Last updated 15th Jan'97