The m3u is your playlist. As is Xtream Codes parameters. Now most IPTV subs are added with Xtream codes and you get however many connections you pay for. M3U8 are usually the free lists and a single connection. So you could have multi screen from a free M3U8 as well as from your paid sub and if say you have a paid sub with 3 connections then you could have 3 screens from them.