Both OMS1 and OMS3 offers video over RTMP.
OMS1 offers full transcoding to H.264 regardless of the input format, but uses (a lot more) CPU to accomplish this. OMS3 offers a non-transcoded video feed for cameras that support H.264. OMS3 does not currently offer live transcoding to H.264.
To set up an RTMP session on OMS3, see the Web Technology section.