I am trying to stream from Simple RTMP Server (SRS) using ffmpeg. I saw there is an option in ffmpeg to specify the rtmp client buffer size, which will be passed to the server when the connection is made. I am interested to know how the client buffer will be used. Does rtmp server always transmit video data at real-time rate, or push the video data as fast as possible until the client buffer is filled up? I want to know if I can maintain a smooth playback even when the connection is intermittent.

Does the RTMP spec specify the default buffer sizes? Or is it implementation specific?