Reducing File Size for E-Learning Media
Let’s say you are developing a beautiful course on which you’ve spent a lot of time finding just the right images, audio, and video. You are excited to release it to your students. They, however, are not excited when the course loads slowly, the videos don’t play, and they use up all of their data plan to view it on their iPads. This illustrates why it is important to consider not only what to include but also how to include it. For example: we recently completed an e-learning course on disaster relief with photos from the organization’s public relations department. We also worked on a harassment prevention course that incorporated scenario photos from a professional photo shoot. Some of these photos had a file size of 10MB or higher. Imagine building an e-learning course with dozens of photos this size–the course size would cause all sorts of problems with the students.
Optimizing your graphic, audio, and video files will help reduce the size of your e-learning courses. Don’t leave it all up to your e-learning authoring tool, though. Resizing pictures or videos on the slide doesn’t change the size of the underlying file. Some optimization is best done to the media before it ever makes it into the authoring tool.
The downside of optimizing media files? It takes some time to do it. But optimizing your e-learning media files can have many positive effects:
- Your previewing and publishing will be faster while developing the course. This means you can get more done in a day!
- Your e-learning course will load more quickly for the end-user, especially on mobile devices. This will result in a better user experience.
- Your end-user will consume less data if they are using a mobile device, which means it will be less expensive for them to take your e-learning course.
Naturally, your next question is, “How do I optimize my media files?” A future blog post will address some of the things you can do inside the tools, but we also do a lot of optimization outside of the authoring tool. Here are some tips:
To reduce file size on graphics, you can, of course, reduce the dimensions. It can hurt your course if you include a 2000 x 1500 graphic in your course just to resize it down to 500 x 400. You can also crop out pieces of the images you’re using if you don’t need the whole image. Authoring tools let you crop and resize, but all the pixels are still saved within the file. If you’re going to crop or resize significantly, it’s probably best to do it externally in a program like SnagIt or Gimp. You can also save the file in the right file format. JPEG, GIF, and PNG are three of the best formats for e-learning. You can use PNG and GIF for images, graphs, charts, and diagrams, as well as small images with text, buttons, icons, and logos. PNG has the advantage of a smaller file size; GIF has the advantage of also working for simple animations. Conventional wisdom says JPEG is best used for photos, but we’ve found that for web work, saving a photo as a GIF or PNG will still look good and take up a lot less memory. Try it in the smallest file type first, and only go up to a JPEG if you aren’t getting the quality you want.
The two easiest ways to reduce audio file size is the file type and the bitrate. The file type (such as MP3, AVI, etc.) determines what type of compression is used. When picking file type, you want to balance file reduction, effect on quality, and how common the file type is. MP3 is a common format that provides a good level of compression without sacrificing quality. Note: you can get much better compression from other formats, but not all e-learning authoring tools or end-user computers will recognize those file types. Adjusting the bitrate, which is a setting you can usually choose when saving, is another way to compress an audio file. The bitrate determines how many bits of data are captured for each wavelength. The more bits, the higher the quality—and the higher the file size. Most narration can use a lower bitrate than typical default settings without losing quality.
The strategies for video combine the strategies for graphics and audio. You can adjust pixel dimensions, change the bitrate on the video’s audio, and find the right file type. An example of video file type is MPEG, RealVideo, FLV, etc.
In a future blog post, I’ll share some best practices and tips on how to maximize your graphic optimization within rapid e-learning development tools, like Articulate Storyline.