HTML5 video doesn't work with live video unfortunately, while flash RTMP streaming does. Alternatives include MPEG DASH and Apple HTTP Live Streaming, but not all browsers support them.
I recall that being a limiting factor 3-4 years ago when I was working with RTMP & P2P/RTMFP, but in mid 2015? I thought HTML5 was ready for live video... Reading now about Media Source Extensions (I just discovered the API) I guess we're finally around the corner... =)
https://w3c.github.io/media-source/