The question concerns YouTube videos. Why do some play straight through without a pause to buffer more data while others of similar lenght constantly pause to refresh the buffer (or cache?)??? It’s so annoying!
There are many factors other than the length of a video that affect how long it takes to load. These include the resolution, the compression, the load on the server, how much other slow-loading junk is on the page, what you have in your cache, and the load on your connection.
Although it doesn’t do a good job of explaining why, YouTube’s help section tells you how to solve this problem. Both of these articles apply to the situation, but the only solution that has worked consistantly for me is to pause the video and wait.
What is particularly annoying is when the progress bar is progressing nicely but the video still pauses.