WebRTC video constraints not working

问题

I'm trying to get a lower resolution from the webcam

navigator.getUserMedia({audio: true, 
    video: {
        "mandatory" : {maxWidth : 320},
        "optional" : []
    }
}, function(stream) {
    videoElement.src = URL.createObjectURL(stream);
}, function(error) {console.log(e)});

Everything works fine, but videoElement.videoWidth is still 640. This is the same whatever video constraints I specify. This is happening only in Firefox, in Chrome everything works fine.

Does anyone know why?

I also tried specifying maxFrameRate, but this is also ignored. I also tried without optional and with maxHeight too.

回答1:

There are numerous bugs that are being handled in Firefox for it not supporting programable video framerate and resolution changes.

Allowing the framerate to be changed in the media constraints
Support runtime change of video resolution
Support plain numbers for the video resolution in the media constraints

You are supposedly able to set the constraints this way:

mediaConstraints = {
      "audio": true,
      "video": {
         width: {
             min: 320,
              max: 320
          },
          height: {
             min: 240,
              max: 240
          } }
    };

But I have never been able to get video resolution constraints to work it to work in Firefox through media constraints. I have had limited success with changing the default resolution in about:config in firefox.

These issues are known and I believe that numerous people are working on them to get them resolved.

来源：https://stackoverflow.com/questions/27159479/webrtc-video-constraints-not-working

标签

javascript

html5

html5-video

webrtc