Red5 only contains a server-implementation (in java).
The python project rtmpy aims to be a free
software implementation of an RTMP library, whilst Tape intends to be a full
streaming server (in Python). rtmpy is in active development.
There is a java client implementation of RTMP, called Flazr.
As of 2nd June 2009 (just two weeks after Adobe issued the take-down notice),
Flazr also has RTMPE support.
Congratulations to Peter, and thank you to Adobe: none of this would have
remotely happened, if you hadn't brought RTMPE to people's attention.
SWFDec has a partial and experimental implementation of RTMP.
swfdec is client-only.
Gnash has a partial and experimental implementations of RTMP.
Gnash has both client and server, sharing the same common source. Cygnal
is making particularly good progress, as a server: video can already be
streamed from it, with real-time video planned for Q3 2009.
libRTMP by boxee contains an RTMP client library, and was used as
the basis for rtmpdump.
haxeVideo is a server implementation of RTMP in Haxe.
crtmpserver is a server implementation of RTMP that has implemented
(as of 25th may 2009) the RTMPE protocol.
Mammoth, formerly known as OpenFMS, is a server implementation
that has implemented an RTMPE-compatible algorithm known as
"H264-compatible and DH handshaking".
RubyIzumi is an implementation of an RTMP server in Ruby.
rtmpdump 此项目是第一个突破RTMPE加密协议的，但因为破解了RTMPE所以惹恼了ADOBE，这个开源项目在SourceForge里已经没有了。但是作者的页面还保留有链接和代码。
http://rtmpd.com/ 这个项目极其庞大，还没有一些深入的了解