It seems the original rtmp module by arut is no longer being maintained. Sergey-dryabzhinsky has a fork of it that still seems to be active. Maybe the docker container can be updated to use that version?
https://github.com/sergey-dryabzhinsky/nginx-rtmp-module
It seems the original rtmp module by arut is no longer being maintained. Sergey-dryabzhinsky has a fork of it that still seems to be active. Maybe the docker container can be updated to use that version? https://github.com/sergey-dryabzhinsky/nginx-rtmp-module