What's the difference of 'addStream' and 'addTrack' of 'RTCPeerConnection'?

[天堂的回响]

I want to replace the audio track of an RTCRtpSender, so I use 'replaceTrack' method of RTCRtpSender, but I found that this method only works if I use 'addTrack' of RTCPeerConnection to add local audio track to it firstly, if I use 'addStream' to add the whole stream got from 'getUserMedia', then 'replaceTrack' will not work, and it cause audio track stopped(Remote peer will not get any audio anymore).My code is like this:

1.Use 'addStream':

navigator.mediaDevices.getUserMedia({audio:true}).then(function(oldStream){

    pc.addStream(oldStream);

    oldStream.getAudioTracks()[0].stop();

    navigator.mediaDevices.getUserMedia({audio:true}).then(function(newStream){

        var newAudioTrack = newStream.getAudioTracks()[0];

        var sender = pc.getSenders().find(function (s) {

            return s.track.kind == newAudioTrack.kind;

        });

        sender.replaceTrack(newAudioTrack);

    });

});

2.Use 'addTrack':

navigator.mediaDevices.getUserMedia({audio:true}).then(function(oldStream){

    pc.addTrack(oldStream.getAudioTracks()[0], oldStream);

    oldStream.getAudioTracks()[0].stop();

    navigator.mediaDevices.getUserMedia({audio:true}).then(function(newStream){

        var newAudioTrack = newStream.getAudioTracks()[0];

        var sender = pc.getSenders().find(function (s) {

            return s.track.kind == newAudioTrack.kind;

        });

        sender.replaceTrack(newAudioTrack);

    });

});

[Sean DuBois]

You could do addTransceiver('audio') and do replaceTrack on the RTCRTPSender that would be created from that.

--

---
You received this message because you are subscribed to the Google Groups "discuss-webrtc" group.
To unsubscribe from this group and stop receiving emails from it, send an email to discuss-webrt...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/discuss-webrtc/7a6595ae-3700-4ffc-9725-da9be2e97a0cn%40googlegroups.com.

[天堂的回响]

addTransceiver('audio') is redundent for after addStream called the transceiver is created automadically.This extra operation make negotiation failed :(

THANKS for your advice!