title: What is the relationship among FFmpeg, librtmp and rtmpdump?
body: <p>I am a beginner of FFmpeg. I can see that video can be pushed to an <a href="https://en.wikipedia.org/wiki/Real_Time_Messaging_Protocol" rel="nofollow noreferrer">RTMP</a> server by FFmpeg or librtmp on the Internet. But I also see that when compiling FFmpeg, I need to add option <em>enable-librtmp</em>. Are they parallel or inclusive? What is rtmpdump? Does the libtrmp API use RTMP lower-level functions directly?</p>