Although WebRTC is great fow low-latency (300 - 500ms). It have some limitation of audio quality. 30 Khz is good for voice or speech conference, but not for music quality grade. So may be RTMP still work for now. 1 second of delay is acceptable.
I I record on mobile phone, also I should use time meter but I have no time. sorry for that.
keyword: RTMP, Livestream, Low delay, Low latency