Our desktop allows you to easily generate bif thumbnails that are compatable with ROKU to use in trick mode.

https://developer.roku.com/en-gb/docs/developer-program/media-playback/trick-mode/trick-mode.md

Simply download the app for free here https://s3bubble.com/aws-encoding-desktop-app/ and in the top menu you will see under our many tools create bif thumbnails.

Its as easy as that.