Video Streaming Protocols Supported

I am aware that HLS is required for most video streaming use cases (watching a movie, TV show, or YouTube video). This is a requirement for all apps. However, I am confused as to whether this would also apply to video chat/video conferencing apps. It would be inefficient to upload compressed video using rtmp/rtp, decompress it, and create HLS segments. Low latency requirements only make this worse. So, is it permissible to use other protocols for video conferencing use cases? Thanks