Description
@Sunoo @longzheng
After reading the two-way audio issue, I think it is worth to create a seperate follow-up issue which only refers to video doorbells that provide two-way audio based on SIP.
(See former discussion here: #738 (comment))
Example devices:
Video is very often just implemented as a MJPEG or H.264 stream via HTTP/RTSP.
I guess there are also SIP video doorbells which offer video as part of the SIP session.
In the former case, the video is normally completely seperate from the audio part via SIP/RTP.
In the later case, I would assume that the video+audio uses SIP early media feature to show video+audio before actually picking up the call (during SIP RINGING).
I think that the homebridge-ring plugin could probably serve as a good starting point as it shows how to implement the SIPclient based on @kirm sip.js lib. It should be easy to then extract the relevant SDP from the SIP INVITE media negotiation.
Remark:
Of course there are a few SIP apps out there which could also somehow cover the use case and also offer Apple VoIP notification feature (like linphone) to receive calls even if the app is not in the foreground.
However, this feature request is to use SIP video doorbells as Homekit video doorbells without any additional app. Only homebridge will talk to the SIP video doorbell.