[mckv]

iptables -t nat -A OUTPUT -p tcp -m iprange --dport 80 (rtmp port) --dst-range 10.0.0.1-10.0.0.10 (rtmp server ip ranges) -m owner --uid-owner username -j REDIRECT --to-port 1935

then run rtmpsrv/rtmpsuck as a different user

note that it only works if the site is actually using rtmp and not uls/hls/hds/dash/etc