Allows a progressive download of a track based on the file key. This should be used for streaming purposes. A lockerPlay URL is auto-generated in lockerData results.
sid (required): A valid session id, received from the "login" method.
partner_token (required): A valid partner token. See Overview for more information.
fileformat (optional): Forces the file to be transcoded and streamed in mp3 format when set to "mp3". Otherwise the file is returned in it's original format. If the MIME type for the file is "video/mp4" or "video/quicktime", the fileformat parameter for lockerPlay will accept "h264" as a valid value and return the video stream.
bitrate (optional): Forces the file to be transcoded to a specified bitrate. valid options are: 28000, 56000, 96000, 128000, or 192000