Some unused output options do not trigger a warning

[KarolGT]

rtsp_transport tcp is ignored when this parameter is not right after ffmpeg command
How to reproduce:

ffmpeg is ignoried in below case:

ffmpeg -i rtsp://192.168.1.201:554/11 -c:v copy -rtsp_transport tcp -an out.mkv 

below case is working fine, as expected:

ffmpeg -rtsp_transport tcp -i rtsp://192.168.1.201:554/11 -c:v copy -an out.mkv


ffmpeg version: tested on 3.1.x and 3.2.x (latest from Nov 08 2016)
built on Linux (Ubuntu)

It will be good to have this information at least in the documentation. It is possible to find this information on some forums like stackoverflow.com but I didn't find any information about this on ffmpeg.org.

[Carl Eugen Hoyos]

Maybe the following command line helps you understanding the issue - option placement does matter - better:

$ ffmpeg -rtsp_transport udp -i rtsp://192.168.1.1/554 -rtsp_transport tcp rtsp://192.168.1.2/554

Iiuc, unused format and protocol options - contrary to encoder options - do not trigger a warning.

$ ffmpeg -i fate-suite/lena.pnm -rtsp_transport tcp -user_agent foo -key bar -write_id3v2 1 -f null -
ffmpeg version N-82235-g222f59a Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl --enable-gnutls
  libavutil      55. 35.100 / 55. 35.100
  libavcodec     57. 66.101 / 57. 66.101
  libavformat    57. 57.100 / 57. 57.100
  libavdevice    57.  2.100 / 57.  2.100
  libavfilter     6. 66.100 /  6. 66.100
  libswscale      4.  3.100 /  4.  3.100
  libswresample   2.  4.100 /  2.  4.100
  libpostproc    54.  2.100 / 54.  2.100
Input #0, ppm_pipe, from 'fate-suite/lena.pnm':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: ppm, rgb24, 256x256, 25 tbr, 25 tbn, 25 tbc
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf57.57.100
    Stream #0:0: Video: wrapped_avframe, rgb24, 256x256, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      encoder         : Lavc57.66.101 wrapped_avframe
Stream mapping:
  Stream #0:0 -> #0:0 (ppm (native) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A speed= 165x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown