Question

我在下面的方法中在Safari Tech Preview 11中获得了未处理的承诺拒绝以初始化WebRTC。具体来说，当我将MediaStream分配给视频元素时会发生这种情况：video.srcObject = event.stream; - 堆栈跟踪显示此行是引发异常的行。我无法使用try/catch.

捕获异常

例外情况仅发生在Safari 11中（Chrome中不会发生）。

以下是方法：

initWebRTC(p){
    var self = this;
    return new Promise((resolve, reject) => {

      self.state.connection = new RTCMultiConnection();
      self.state.connection.socketMessageEvent = 'webrtc-firebase';
      self.state.connection.setCustomSocketHandler(FirebaseConnection);
      self.state.connection.firebase = 'webrtc-firebase'; 
      self.state.connection.enableFileSharing = true; 
      self.state.connection.session = {
        audio: true,
        video: true,
        data: true
      };
      self.state.connection.sdpConstraints.mandatory = {
        OfferToReceiveAudio: true,
        OfferToReceiveVideo: true
      };
      self.state.connection.onstream = function(event) {
          console.log('event.mediaElement',event.mediaElement);
          console.log('event.stream',event.stream);

          var videoContainer = document.getElementById('videoContainer');
          var video = event.mediaElement;
          if (!window.safari){
            var source = document.createElement("source");
            source.srcObject = event.stream;
            video.appendChild(source);
          } else { // Safari
            try{
              video.srcObject = event.stream; // this is the line that throws the exception
            }catch(e){ //unable to catch the exception
              console.log('exception',e);
            }
          }
          videoContainer.appendChild(video);

          var playPromise = video.play();
          if (playPromise !== undefined) { // not a Promise in some browsers
            playPromise.catch(function(error) {
            });
          }
          setTimeout(function() {
            var playPromise = video.play();
            if (playPromise !== undefined) {
              playPromise.catch(function(error) {
              });
            }
          }, 5000);
      };
      resolve();
    });
  }

不确定这是否有帮助，但这是跟踪：

[Error] Unhandled Promise Rejection: [object DOMError]
    (anonymous function)
    rejectPromise
    onstream (index.js:5787) // this is the video.srcObject = event.stream; line
    (anonymous function) (RTCMultiConnection.js:4092)
    getRMCMediaElement (RTCMultiConnection.js:1113)
    onGettingLocalMedia (RTCMultiConnection.js:4064)
    onGettingLocalMedia (RTCMultiConnection.js:4984)
    streaming (RTCMultiConnection.js:3289)
    (anonymous function) (RTCMultiConnection.js:3358)
    promiseReactionJob

任何帮助将不胜感激。谢谢！

Answer 1

Safari 11默认禁止自动播放任何带声音的视频（source）。

我相信video元素附带了autoplay属性。当您将srcObject设置为它时，它会尝试播放视频 - 然后被Safari阻止。这就是你看错的原因。

您可以尝试从视频元素中删除autoplay，然后您就可以在playPromise.catch中抓住它。

Answer 2

我不知道这是否适合您，但我有类似的问题，修复是在视频标记中添加'muted'属性，之后一切都恢复正常，希望它有所帮助。

MediaStream未处理的承诺拒绝：[object DOMError]（在Safari 11中）

2 个答案: