This seems especially true for e-learning developers new in the Flash space, who are sometimes seen creating entire lessons or courses in one large Flash movie.
When you develop e-learning courses in a desktop environment and preview them locally, it's easy to forget that once you post them out on the web, the course could become largely unusable for some users because of bandwidth connection speeds.
It appears that many of the e-learning software tools for computer-based training don't address this very well either. I have heard complaints about Captivate, Articulate, and Lectora producing files impractical in size. In fairness, I don't know why this is happening in those cases, and this may be because the users aren't setting them up correctly--I'm not intimately familiar with those tools. All I know if how we designed Rapid Intake's tools.
Modular Content Design and Delivery
From the outset we designed Rapid Intake ProForm and Unison so the courses would load as quickly as possible? How is this accomplished in Flash if you have a lot of content? The answer is through modularization.
In Rapid Intake, the course interface (table of contents, media controllers, etc.) loads first along with SCORM LMS data communication pieces. This totals about 90K and is the minimum for the course to run. Once that course interface (also called a "wrapper") is loaded, the content pieces the learner has requested load separately as needed. So if the learner goes to page 1, it only loads the first page's content.
Because the content is all driven by XML, the objects, such as video, audio, images, and other Flash movies, reside outside the course structure and are loaded dynamically, loading when the learner needs them.
How to Handle Large Video
What about large video files? Yes, in some cases you need to pre-load, but instead of pre-loading the whole file, do a progressive download and specify what percentage of the file should be downloaded before it starts playing. Many Rapid Intake users leave the default (50%), but on a very long video the learner would have to wait too long, so we recommend lowering that. On a very short video, you may want to have the video download at 100% because it won't take long and there is the risk that the learner's playback will get ahead of the download. (You could also do true streaming, but that is a separate conversation.)
Whether you are building your e-learning from scratch, or using rapid e-learning development tools like those at Rapid Intake, use a modular approach to content delivery to make the most of whatever bandwidth connection your learner has.