ERROR: unable to open RTSP for listening / Cannot assign requested address

[stbuerger]

Trying to use a RTSP (h.265) camera (Steinel L620) stream in browser with go2rtc-1.9.2 I only get errors on address. The errors only appear when using a URL of type "ffmpeg:rtsp://MYIP:554/MYPATH" -- whereas "rtsp://MYIP:554/MYPATH" doesn't give errors - but Chrome&FF browser do not support h.265 with WebRTC an therefor I need to use ffmpeg for transcoding to h.264.

with go2rtc.yaml:

streams:
  L620HT: 
    - "ffmpeg:rtsp://192.168.1.63:554/user=admin&password=MYSECRET&channel=1&stream=0.sdp#video=h264#audio=opus"
log:
  level: info
  api: debug
  rtsp: debug
  streams: debug
  webrtc: debug
  exec: debug

running go2rtc and and just using web-ui/"probe" or access "stream" URL results in:

21:42:31.990 INF go2rtc platform=linux/amd64 revision=b2399f3 version=1.9.2 21:42:31.990 INF config path=/home/stefan/go2rtc/go2rtc.yaml 21:42:31.991 INF [rtsp] listen addr=:8554 21:42:31.991 INF [api] listen addr=:1984 21:42:31.991 INF [webrtc] listen addr=:8555/tcp 21:42:59.265 DBG [webrtc] new consumer src=L620HT 21:42:59.267 DBG [exec] run cmd="ffmpeg -hide_banner -v error -allowed_media_types video+audio -fflags nobuffer -flags low_delay -timeout 5000000 -user_agent go2rtc/ffmpeg -rtsp_flags prefer_tcp -i rtsp://192.168.1.63:554/user=admin&password=MYSECRET&channel=1&stream=0.sdp -c:v libx264 -g 50 -profile:v high -level:v 4.1 -preset:v superfast -tune:v zerolatency -pix_fmt:v yuv420p -c:a libopus -application:a lowdelay -min_comp 0 -user_agent ffmpeg/go2rtc -rtsp_transport tcp -f rtsp rtsp://127.0.0.1:8554/802bfa2f1f149eaa99fddbcbc83395c8" url="exec:ffmpeg -hide_banner -v error -allowed_media_types video+audio -fflags nobuffer -flags low_delay -timeout 5000000 -user_agent go2rtc/ffmpeg -rtsp_flags prefer_tcp -i rtsp://192.168.1.63:554/user=admin&password=MYSECRET&channel=1&stream=0.sdp -c:v libx264 -g 50 -profile:v high -level:v 4.1 -preset:v superfast -tune:v zerolatency -pix_fmt:v yuv420p -c:a libopus -application:a lowdelay -min_comp 0 -user_agent ffmpeg/go2rtc -rtsp_transport tcp -f rtsp rtsp://127.0.0.1:8554/802bfa2f1f149eaa99fddbcbc83395c8" [rtsp @ 0x5572ab117040] Unable to open RTSP for listening rtsp://192.168.1.63:554/user=admin&password=MYSECRET&channel=1&stream=0.sdp: Cannot assign requested address 21:42:59.352 DBG [webrtc] add consumer error="streams: exec: [rtsp @ 0x5572ab117040] Unable to open RTSP for listening\nrtsp://192.168.1.63:554/user=admin&password=MYSECRET&channel=1&stream=0.sdp: Cannot assign requested address\n"

Interesting other information: FFPLAY works OK as ..

ffplay -hide_banner -v error -allowed_media_types video+audio -fflags nobuffer -flags low_delay -timeout 5000000 -user_agent go2rtc/ffmpeg -rtsp_flags prefer_tcp -i "rtsp://192.168.1.63:554/user=admin&password=MYSECRET&channel=1&stream=0.sdp"

Any hints what I could be doing wrong here or how I can further debug this.