ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 8.3.0 (Alpine 8.3.0)
  configuration: --prefix=/usr --enable-avfilter --enable-gpl --enable-libx264 --enable-static --enable-small --disable-ffplay --disable-ffprobe --disable-doc --disable-htmlpages --disable-manpages --disable-podpages --disable-txtpages --disable-w32threads --disable-alsa --disable-audiotoolbox --disable-cuda --disable-cuvid --disable-d3d11va --disable-dxva2 --disable-nvenc --disable-vaapi --disable-vdpau --disable-videotoolbox --disable-librtmp --disable-devices --enable-indev=xcbgrab --disable-debug
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
[x11grab @ 0x561929991100] Cannot open display browser:99, error 1.