According to the public RTMP specification, these 4 bytes should be zero.
librtmp in server mode assumes that the RTMPE (FP9) handshake is used if these bytes are nonzero.
7d8d726 rtmpproto: Don't include a client version in the unencrypted C1 handshake
libavformat/rtmpproto.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
Upstream: git.libav.org