What is Mammoth Server?
Mammoth is an Open Source c++ Flash Server software that enables you to stream, video and audio on the web. Has built-in support for all possible flash codecs (thank you ffmpeg!) h264, sorenson, speex, ... and streams through rtmp, rtmpe, rtmpt.
Mammoth Server seems to be another implementation based on Red5 code. They specially mention it on their website.
Last activities dated back to 2009. The source code is still downloadable from SourceForge Repositories
Mammoth Server Screenshots
Mammoth Server Features
Mammoth Server information