var getUser_media = function (constraints, success, errFunc) {
                    if (navigator.mediaDevices.getUserMedia) {
                        //最新的标准API
                        navigator.mediaDevices.getUserMedia(constraints).then(success).catch(errFunc);
                    } else if (navigator.webkitGetUserMedia) {
                        //webkit核心浏览器
                        navigator.webkitGetUserMedia(constraints,success, errFunc)
                    } else if (navigator.mozGetUserMedia) {
                        //firfox浏览器
                        navigator.mozGetUserMedia(constraints, success, errFunc);
                    } else if (navigator.getUserMedia) {
                        //旧版API
                        navigator.getUserMedia(constraints, success, errFunc);
                    }
                };

                await getUser_media(constraints, gotLocalMediaStream, function(err) {
                    console.log('getUserMedia 错误', err);
                    //创建点对点连接对象
                });

获取到媒体文件流后

  // getUserMedia 获得流后，将音视频流展示并保存到 localStream
            function gotLocalMediaStream(mediaStream) {
                console.log('mediaStream', mediaStream);
                localStream = mediaStream;

                //https://blog.csdn.net/chendongpu/article/details/123105777
                // 旧的浏览器可能没有srcObject
                if ("srcObject" in videoPlayer) {
                    videoPlayer.srcObject = mediaStream;
                } else {
                    //避免在新的浏览器中使用它，因为它正在被弃用。
                    videoPlayer.src = window.URL.createObjectURL(mediaStream);
                }
                videoPlayer.onloadedmetadata = function (e) {
                    videoPlayer.play();
                };


                videoPlayer.play();
                lrBox.noLoading();
                if(funcAfterDevice) {
                    funcAfterDevice();
                }
            }