Ahh think I may have found the answer here:
Additional [s2Stream /] Shortcode Attributes:
See also: API Function s2member_file_download_url() for PHP integration.
file_download=”video.mp4″ Location of the audio/video file, relative to the /s2member-files/ directory; or, relative to the root of your Amazon® S3 Bucket, when applicable.
player=”jwplayer-v6-rtmp” Required. Current supported players in this Shortcode include: jwplayer-v6 (works with any audio/video file, and you do NOT need to have Amazon® S3 or CloudFront™ integrated for this to work), jwplayer-v6-rtmp (streams with the RTMP protocol, plus there is a full download fallback of the source file if streaming is not possible on a particular device; this requires both Amazon® S3 and CloudFront™ integration), jwplayer-v6-rtmp-only (streams with the RTMP protocol only, with no access to the source file, only to the RTMP stream; this requires both Amazon® S3 and CloudFront™ integration).
player_id=”” Optional. HTML div ID for the audio/video player. Defaults to a unique ID generated by s2Member® for each instance of your Shortcode.
player_path=”/jwplayer/jwplayer.js” Required. Path to the player’s JavaScript file (ex: /jwplayer/jwplayer.js — you should upload the /jwplayer folder to the root of your web directory).
player_[setting]=”” Optional. Any additional attributes supported by your audio/video player, prefixed with player_. For JW Player™ v6, see this article please. Examples: player_width=”480″, player_height=”270″, player_image=”http://www.example.com/wp-content/uploads/video-preview.jpg”, player_autostart=”true”, player_skin=”/jwplayer/my-skin.xml”. Please note that “Advanced Options Blocks” listed on this page are currently NOT supported here. All others are.