SRT in and out

[JonnyTech]

Question

I am testing locally before trying on a LAN.

Running mediamtx_v1.8.5_linux_amd64 on Debian 11 with default yml config apart from loglevel:

logLevel: debug

$ ./mediamtx 
2024/08/12 17:05:30 INF MediaMTX v1.8.5
2024/08/12 17:05:30 INF configuration loaded from /opt/mediamtx/mediamtx.yml
2024/08/12 17:05:30 DEB path manager created
2024/08/12 17:05:30 INF [RTSP] listener opened on :8554 (TCP), :8000 (UDP/RTP), :8001 (UDP/RTCP)
2024/08/12 17:05:30 INF [RTMP] listener opened on :1935
2024/08/12 17:05:30 INF [HLS] listener opened on :8888
2024/08/12 17:05:30 INF [WebRTC] listener opened on :8889 (HTTP), :8189 (ICE/UDP)
2024/08/12 17:05:30 INF [SRT] listener opened on :8890 (UDP)

Then starting a feed with ffmpeg:

$ ~/ffmpeg -re -f lavfi -i "movie=filename=video.mp4:loop=0" -c:v libx264 -f mpegts srt://localhost:8890?streamid=publish:mystream

The log shows the stream:

2024/08/12 17:05:56 INF [SRT] [conn [::1]:49180] opened
2024/08/12 17:05:56 DEB [path mystream] created
2024/08/12 17:05:58 INF [SRT] [conn [::1]:49180] is publishing to path 'mystream', 1 track (H264)

Then using ffplay to view then stream:

~/ffplay -fs -f mpegts srt://127.0.0.1:8890?streamid=read:mystream

The log shows it receiving:

2024/08/12 17:06:45 INF [SRT] [conn 127.0.0.1:36777] opened
2024/08/12 17:06:45 INF [SRT] [conn 127.0.0.1:36777] is reading from path 'mystream', 1 track (H264)

But nothing is received:

    nan    :  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B 

Checking that SRT is supported:

$ ~/ffmpeg -protocols |grep -i srt
ffmpeg version N-116557-g1b8d95da3a-20240810 Copyright (c) 2000-2024 the FFmpeg developers
  built with gcc 14.2.0 (crosstool-NG 1.26.0.106_ed12fa6)
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-ffbuild-linux-gnu- --arch=x86_64 --target-os=linux --enable-gpl --enable-version3 --disable-debug --enable-iconv --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-libxml2 --enable-openssl --enable-lzma --enable-fontconfig --enable-libharfbuzz --enable-libvorbis --enable-opencl --enable-libpulse --enable-libvmaf --enable-libxcb --enable-xlib --enable-amf --enable-libaom --enable-libaribb24 --enable-avisynth --enable-chromaprint --enable-libdav1d --enable-libdavs2 --enable-libdvdread --enable-libdvdnav --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libgme --enable-libkvazaar --enable-libaribcaption --enable-libass --enable-libbluray --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librist --enable-libssh --enable-libtheora --enable-libvpx --enable-libwebp --enable-libzmq --enable-lv2 --enable-libvpl --enable-openal --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-librav1e --enable-librubberband --disable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --enable-libdrm --enable-vaapi --enable-libvidstab --enable-vulkan --enable-libshaderc --enable-libplacebo --enable-libvvenc --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-libs='-ldl -lgomp' --extra-ldflags=-pthread --extra-ldexeflags=-pie --cc=x86_64-ffbuild-linux-gnu-gcc --cxx=x86_64-ffbuild-linux-gnu-g++ --ar=x86_64-ffbuild-linux-gnu-gcc-ar --ranlib=x86_64-ffbuild-linux-gnu-gcc-ranlib --nm=x86_64-ffbuild-linux-gnu-gcc-nm --extra-version=20240810
  libavutil      59. 33.100 / 59. 33.100
  libavcodec     61. 11.100 / 61. 11.100
  libavformat    61.  5.101 / 61.  5.101
  libavdevice    61.  2.100 / 61.  2.100
  libavfilter    10.  2.102 / 10.  2.102
  libswscale      8.  2.100 /  8.  2.100
  libswresample   5.  2.100 /  5.  2.100
  libpostproc    58.  2.100 / 58.  2.100
  srtp
  srt
  srtp
  srt

What am I doing wrong?