To preview a SWF/FLV file selected in a Task List you may use Flash player window which helps users find necessary files within the Tasks List faster.

Apart of movie player window and controls (stop/start, pause, frame-by-frame preview, load next/previous movie) Flash player provides extensive information about currently selected SWF/FLV file such as name, window dimensions, file size, number of frames in the movie, frames per second, Macromedia Flash version which was used to create this file and compression indicator.
Please, note that by default Flash player displays the first SWF/FLV file in the Task List. Moreover, frame-by-frame preview buttons are not available for FLV files.