i got this message from ffmpeg:
Stream #0:0: Video: h264 (Main), yuvj420p(pc, bt709, progressive), 1280x720, 14.99 fps, 14.99 tbr, 90k tbn, 180k tbc
[rtsp @ 0x16454e0] method ANNOUNCE failed: 501 Not Implemented
Could not write header for output file #0 (incorrect codec parameters ?): Server...