To handle FLV files, we need to instruct PoodLL to handle FLV and then tell it which player to use. FLV can be audio or video. Unfortunately PoodLL can not guess which, so you must choose one or the other when you select the player to use. It is likely to be video in most cases.  

Visit : Site administration -> plugins -> filters -> Poodll filter -> file extension settings

Choose to "Handle FLV" and select a player to do do.

For audio choose: mediaelement audio and for video choose; mediaelement video or flowplayer first frame.