With a dynamic playlist, we mean a list of videos or audios with expiring URLs (also called signed urls).  The links are dynamically created, i.e.: on the fly.
With Footprint Player, you can create a playlist with up to 20 items.

Dynamic playlist with private mp4 videos. On the left, a clickable logo.  Video 3 (Lost corners) has subtitles: 

It is perfectly possible to have a playlist with HLS adaptive streaming videos. In this playlist, we did not set poster images. With HLS videos, the first frame of the video is shown in the video area. The list on the right is blank in that case.  The first video has an Amazon S3-Managed Key (SSE-S3) , the others have normal encryption.  Note also that there is a logo (top-left)which can be set in four positions: