无法为“输出”找到合适的输出格式

Question

我正在通过SSH运行此命令；

ffmpeg -f concat -safe 0 -i "https://domain.co.uk/playlist.txt" output -f flv "rtmp://ip/live/test"

但是我遇到以下错误；

  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x9e1cc0] Auto-inserting h264_mp4toannexb bitstream f
Input #0, concat, from 'https://domain.co.uk/playlist.txt':
  Duration: N/A, start: 0.000000, bitrate: 258 kb/s
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yu
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, flt
    Metadata:
      handler_name    : SoundHandler
[NULL @ 0xd4fa60] Unable to find a suitable output format for 'output'
output: Invalid argument

感谢您的任何帮助。我想我只是想念-f flv的输出格式，但这没用。