I am looking to build a widget for a site which allows users to tag images from individual frames of a video file but would prefer not to have to build a custom Flash tool. Is there an existing free library or framework which simplifies things like this in a webapplication setting? Features would also involve basic video playback functionality as well as time-driven meta-data and the ability to extract images from individual video frames.
Are there existing open-source web-based tools for video manipulation other than building your own custom Flash app?