Reduce CPU usage with RTMFT video chatting

Question

Hi,
We are using the FMS4 for 1-1 real time video chatting. it is fine but the CPU usage are very high.
(not P2P but use UDP based RTMFP) currently connection to server as " rtmfp://1.2.3.4:80/live"
we use the :80 I guess it helps to deal with the firewall with HTTP tunneling? (seems if it is true, it will this degrade performance?)
with 320*240; it is using 30~50 % CPU;  with 480*360: 40-60% CPU at the clients.  so high... decent client machine: Intel i5 650. Quad 3.3Ghz  8G RAM. win7 64
Any idea on reducing cpu usage?

Answer 1

RTMFP is a UDP-based protocol and does not currently tunnel over HTTP.  when you specify port 80 with RTMFP, you're using UDP port 80, not TCP port 80.  also, that port 80 is the fmsedge port; you will be redirected to a different port (19350+ by default) for the true client-server connection.
RTMFP has significantly higher overhead than RTMP for two main reasons: 1) RTMFP is a complete network transport protocol of similar complexity to TCP, but implemented entirely in user space instead of in the operating system kernel, so every packet sent on the network requires special processing and at least one context switch to kernel mode for transmission or reception; 2) every byte of every packet in RTMFP is encrypted with AES-128-CBC, a non-trivial cipher requiring a not-insubstantial amount of CPU.  there is no unencrypted form of RTMFP.