Popcorn-chain-plugin is a project mainly written in JavaScript, it's free.
Popcorn Chain Plugin can be used to load and execute additional Popcorn scripts and their accompanying videos, at time specified by the user.
Example:
var p = Popcorn('#video')
.chain({
start : 4, // Preloads new video file
end : 8, // Plays new video, loads new popcorn data, replaces old events with new events
video : 'my-video.webm', // The url of the next video file to be loaded
popcorn : 'my-popcorn-script.js' // The url of the next Popcorn Script to be loaded
})Demo: http://code.bocoup.com/popcorn.js/chain-plugin-demo/popcorn.chain.html