Table of Contents

Introduction

This page focuses on creating MPEG-1 movies (video only) using NERSC. The resultant movies can be played using any MPEG-1 player or on a web page. This page describes what you need to consider before you make your movie; some methods for creating a movie; and some advanced tips for the more adventuresome user. Note: The example movies shown in this page do not reflect the normal quality of output from the graphics & visualization packages used. We picked the worst way to create the images and movies to illustrate what you should not do.

Creating a movie is at least a two step process. First you need to create the individual frames that will comprise your movie. You then need to combine these images to create a movie that you and others can play back on a computer. Almost all computer-generated movie formats use a compression algorithm. Compression is necessary because of size constraints (size of image times the number of the images to make a movie (30 frames per second) equals hundreds to thousands of megabytes). The MPEG-1 standard is one movie format that supports a very good compression scheme. Others possible formats are Apple's QuickTime, and Microsoft's AVI. This page focuses on MPEG because most platforms support MPEG-1 players and there are lots of plug-ins available for web browsers.

When you decide to make your movie, be prepared to spend more time on creating the movie than you first thought or you would like to. Movie making is an art. There is no cookbook that will tell you exactly what you need to do to create your perfect movie. Factors that contribute to the problem is that the final movie size may be the most important factor to one user, another user is more interested in the highest-quality image, and yet another is interested in portability.

If you are interested in learning more about video and various standards like MPEG, check out the web and books and magazines on video, it's creation, and deployment. Click here to go to the official web site of the Movie Picture Experts Group (MPEG).

Before You Make Your Image Files

Things to consider before you make the images for your movie:

Tools to Create MPEG Movies

MPEG Encoders

An MPEG encoder is a software tool that takes individual raster image files, and generates an MPEG movie. The following MPEG encosders applications are available for your use on NERSC's DaVinci system.

Applications that Include MPEG Encoders

In contrast to the MPEG encoders described above - where you provide a number of image files as input and obtain a finished MPEG movie on output, the following visualization applications are capable of directly generating MPEG movies. In other words, you don't have to perform the intermediate step of generating raster image files prior to running the encoder

Try out each of the above applications and encoders to determine which produces acceptable MPEG quality and resolution. Here are two sample movies that show how MPEGs created from each of the applications. The movie consists of an animation of small bouncing balls. Default values were used for the compression parameters in each application's encoder.

In this case, mediaconvert did a better job than mpeg_encode but created a larger file (490K versus 90K). mpeg_encode did a better job when the balls were made a little larger and the colors were de-saturated. Movie 1, notice the balls are not distorted. Movie 2, the balls are distorted.

You can play with changing the compression scheme by modifying the number of I, P, and B frames. The definition of these frame types are detailed in any article on MPEG. Basically, the more B and P frames you specify, the more compression. You can visit the Berkeley MPEG Group's website for more information.

Additional/Advanced Tips for Creating MPEG Movies

Applications and Tools for Raster Image Manipulation

The applications and tools described in this section are useful for performing operations on raster image files. In addition to these, which comprise a collection somewhat specific to creating MPEGs on NERSC platforms, we also provide a variety of raster image manipulation tools. These are described in the Image Manipulation Applications section of the NERSC Visualization Software page.

Displaying Movies

The applications you may be familiar with for playing movies (e.g., Windows Media Player, Apple's Quicktime Player) are not installed on NERSC platforms. We suggest that you download the MPEGs to your workstation and verify that the quality and resolution are visually acceptable using the commodity players.

  • Format Conversion
    ffmpeg can also perform movie format conversion. See the ffmpeg documentation for more information.
  • Additional Information - Presentations, etc.