Exec

Exec source can run any external application and expect data from it. Two transports are supported - pipe (new in v1.5.0) and RTSP.

If you want to use RTSP transport, the command must contain the {output} argument in any place. On launch, it will be replaced by the local address of the RTSP server.

pipe reads data from app stdout in different formats: MJPEG, H.264/H.265 bitstream, MPEG-TS. Also pipe can write data to app stdin in two formats: PCMA and PCM/48000.

The source can be used with:

• FFmpeg - go2rtc ffmpeg source is just a shortcut to exec source
• FFplay - play audio on your server
• GStreamer
• Raspberry Pi Cameras
• any of your own software

Configuration

Pipe commands support parameters (format: exec:{command}#{param1}#{param2}):

• killsignal - signal which will be sent to stop the process (numeric form)
• killtimeout - time in seconds for forced termination with sigkill
• backchannel - enable backchannel for two-way audio
• starttimeout - time in seconds for waiting first byte from RTSP

streams:
  stream: exec:ffmpeg -re -i /media/BigBuckBunny.mp4 -c copy -rtsp_transport tcp -f rtsp {output}
  picam_h264: exec:libcamera-vid -t 0 --inline -o -
  picam_mjpeg: exec:libcamera-vid -t 0 --codec mjpeg -o -
  pi5cam_h264: exec:libcamera-vid -t 0 --libav-format h264 -o -
  canon: exec:gphoto2 --capture-movie --stdout#killsignal=2#killtimeout=5
  play_pcma: exec:ffplay -fflags nobuffer -f alaw -ar 8000 -i -#backchannel=1
  play_pcm48k: exec:ffplay -fflags nobuffer -f s16be -ar 48000 -i -#backchannel=1

Backchannel

• You can check audio card names in the Go2rtc > WebUI > Add
• You can specify multiple backchannel lines with different codecs

sources:
  two_way_audio_win:
    - exec:ffmpeg -hide_banner -f dshow -i "audio=Microphone (High Definition Audio Device)" -c pcm_s16le -ar 16000 -ac 1 -f wav -
    - exec:ffplay -nodisp -probesize 32 -f s16le -ar 16000 -#backchannel=1#audio=s16le/16000
    - exec:ffplay -nodisp -probesize 32 -f alaw -ar 8000 -#backchannel=1#audio=alaw/8000