get https://api.mediasilo.com/v3/assets//webvtt
Returns a webvtt file containing image sprites
Returns a webvtt formatted document document containing links to time-coded sprite files. WebVTT is a format spec used for captions, subtitles, and thumbnails. It is used by most standard video players.
Each thumbnail contains a signature which expires within 1 hour + video play time.
&Expires=1421700850&AWSAccessKeyId=AKIAIXVIEBTFMV67JL4Q&Signature=Ommdbcu5giFMVT8x7z3JTAVYw00%3D#xywh=238,0,119,67
Should your client application (e.g video player) throw an error while trying to load the sprite files, simply re-request the webvtt files to reset the expiration time.