I have had a look at a couple of players like Flow Player, JW Player and a couple more but I can\'t get it to work exactly in PHP code.
Is there any way to play FLV
Technically speaking the HTML5 video specification is codec/protocol agnostic so one could imagine support for flv files could be possible. Problem is: none of the major web browser has implemented it (probably because flv is a proprietary container from Adobe). You will need a flash component to play it back. Either one of the players you mentioned or if you are looking for a standalone free flash player try strobe from Adobe. You can try it here.
If you can produce .f4v files you may have success in renaming them to mp4 and then try and play them in an HTML5 video tag.