diff --git a/src/matrix.js b/src/matrix.js
index 43d1a1c24..f75e66855 100644
--- a/src/matrix.js
+++ b/src/matrix.js
@@ -88,21 +88,21 @@ module.exports.createNewMatrixCall = require("./webrtc/call").createNewMatrixCal
 
 
 /**
- * Set an audio output device to use for MatrixCalls
+ * Set a preferred audio output device to use for MatrixCalls
  * @function
  * @param {string=} deviceId the identifier for the device
  * undefined treated as unset
  */
 module.exports.setMatrixCallAudioOutput = require('./webrtc/call').setAudioOutput;
 /**
- * Set an audio input device to use for MatrixCalls
+ * Set a preferred audio input device to use for MatrixCalls
  * @function
  * @param {string=} deviceId the identifier for the device
  * undefined treated as unset
  */
 module.exports.setMatrixCallAudioInput = require('./webrtc/call').setAudioInput;
 /**
- * Set a video input device to use for MatrixCalls
+ * Set a preferred video input device to use for MatrixCalls
  * @function
  * @param {string=} deviceId the identifier for the device
  * undefined treated as unset
diff --git a/src/webrtc/call.js b/src/webrtc/call.js
index 3611c49c1..da3b64de7 100644
--- a/src/webrtc/call.js
+++ b/src/webrtc/call.js
@@ -583,7 +583,7 @@ MatrixCall.prototype._maybeGotUserMediaForInvite = function(stream) {
             ' Or possibly you are using an insecure domain. Receiving only.');
         this.peerConn = _createPeerConnection(this);
     } else {
-        debuglog('Failed to getUserMedia.');
+        debuglog('Failed to getUserMedia: ' + error.name);
         this._getUserMediaFailed(error);
         return;
     }
@@ -1274,15 +1274,15 @@ const _getUserMediaVideoContraints = function(callType) {
         case 'voice':
             return {
                 audio: {
-                    deviceId: audioInput ? {exact: audioInput} : undefined,
+                    deviceId: audioInput ? {ideal: audioInput} : undefined,
                 }, video: false,
             };
         case 'video':
             return {
                 audio: {
-                    deviceId: audioInput ? {exact: audioInput} : undefined,
+                    deviceId: audioInput ? {ideal: audioInput} : undefined,
                 }, video: {
-                    deviceId: videoInput ? {exact: videoInput} : undefined,
+                    deviceId: videoInput ? {ideal: videoInput} : undefined,
                     /* We want 640x360.  Chrome will give it only if we ask exactly,
                        FF refuses entirely if we ask exactly, so have to ask for ideal
                        instead */