FFmpeg as rtmp server is not working

[mmzeeman]

Summary of the bug:

How to reproduce:

 ffmpeg -loglevel 99 -safe 0 -protocol_whitelist file,http,https,tcp,tls,rtmp -listen 1 -f flv -i rtmp://0.0.0.0:1234/live out.m3u8

Here I'm trying to start ffmpeg as a rtmp server without user credentials. The server should start and wait for input, but instead I get an unknown error.

Full output:

$ ffmpeg -loglevel 99 -safe 0 -protocol_whitelist file,http,https,tcp,tls,rtmp -listen 1 -f flv -i rtmp://0.0.0.0:1234/live out.m3u8
ffmpeg version 4.1.4 Copyright (c) 2000-2019 the FFmpeg developers
  built with Apple LLVM version 10.0.1 (clang-1001.0.46.4)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.4_1 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-12.0.1.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-12.0.1.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100
Splitting the commandline.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument '99'.
Reading option '-safe' ... matched as AVOption 'safe' with argument '0'.
Reading option '-protocol_whitelist' ... matched as AVOption 'protocol_whitelist' with argument 'file,http,https,tcp,tls,rtmp'.
Reading option '-listen' ... matched as AVOption 'listen' with argument '1'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'flv'.
Reading option '-i' ... matched as input url with argument 'rtmp://0.0.0.0:1234/live'.
Reading option 'out.m3u8' ... matched as output url.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option loglevel (set logging level) with argument 99.
Successfully parsed a group of options.
Parsing a group of options: input url rtmp://0.0.0.0:1234/live.
Applying option f (force format) with argument flv.
Successfully parsed a group of options.
Opening an input file: rtmp://0.0.0.0:1234/live.
[flv @ 0x7fc99d800400] Opening 'rtmp://0.0.0.0:1234/live' for reading
rtmp://0.0.0.0:1234/live: Unknown error occurred