The Video Transcoder determines which part of the video is used as the "still" image when a video file is uploaded into the community. By default, the 5 second mark is used by Video Transcoder to select the preview image. This can be adjusted in the site configuration, it's the "Poster Second" setting. This setting can be modified, but does implement this across the entie community.
- Click on Pencil Icon
- Select Administration
- Select File Viewers
- Click on Video Transcoder
- Find Poster Second: The point in the video's playback (at that second) where it takes a screenshot for displaying as the video's preview and thumbnail.