Flowplayer Flash's Time line thumbnails plugin simplifies the process of generating and displaying images on the player's seek bar when a user hovers over it. The plugin eliminates the need to prepare and store thumbnails, as it automatically handles the task for smoother video playback.

Using byte-range http requests, the plugin efficiently downloads meta data and necessary key frames. To enable seamless functionality, your H264 mp4s should have enough key frames, which can be arranged through settings during the encoding process or occur naturally with every scene change.
One of many plugins in a series based on http multistreaming and mp4 parsing using javascript/actionscript, Time line thumbnails is a must-have for users wanting to improve Flowplayer Flash's preview functionality.
Version 1.0.1: First release: generate visuals from H264 mp4 key frames on the fly in the browser