I want to display a thumbnail representing a specific frame within a video currently hosted on an SaaS video. How do I specify a specific video thumbnail?
Replace a poster image by appending directly to the individual video viewer URL (&videoPlayer.posterimage=).
http://microsite.omniture.com/t2/help/en_US/s7/viewers_ref/index.html#VideoPlayerposterimage
Pick a video thumbnail
The Adobe Scene7 algorithm for selecting a video thumbnail chooses the first frame. If the first frame is monochromatic (primarily one color), it keeps moving along the video timeframe until a more contrasting frame is available. The primary reason is to avoid things like black intro or scene transition frames, which do not make good thumbnails. You can override the individual poster image using the poster image modifier.