diff --git a/static/js/controllers/mediastreamcontroller.js b/static/js/controllers/mediastreamcontroller.js
index 17b4e0f4..0b9df218 100644
--- a/static/js/controllers/mediastreamcontroller.js
+++ b/static/js/controllers/mediastreamcontroller.js
@@ -20,7 +20,7 @@
  */
 define(['jquery', 'underscore', 'angular', 'bigscreen', 'moment', 'sjcl', 'modernizr', 'webrtc.adapter'], function($, _, angular, BigScreen, moment, sjcl, Modernizr) {
 
-	return ["$scope", "$rootScope", "$element", "$window", "$timeout", "safeDisplayName", "safeApply", "mediaStream", "appData", "playSound", "desktopNotify", "alertify", "toastr", "translation", "fileDownload", "localStorage", "screensharing", "userSettingsData", "localStatus", "dialogs", "rooms", function($scope, $rootScope, $element, $window, $timeout, safeDisplayName, safeApply, mediaStream, appData, playSound, desktopNotify, alertify, toastr, translation, fileDownload, localStorage, screensharing, userSettingsData, localStatus, dialogs, rooms) {
+	return ["$scope", "$rootScope", "$element", "$window", "$timeout", "safeDisplayName", "safeApply", "mediaStream", "appData", "playSound", "desktopNotify", "alertify", "toastr", "translation", "fileDownload", "localStorage", "screensharing", "userSettingsData", "localStatus", "dialogs", "rooms", "constraints", function($scope, $rootScope, $element, $window, $timeout, safeDisplayName, safeApply, mediaStream, appData, playSound, desktopNotify, alertify, toastr, translation, fileDownload, localStorage, screensharing, userSettingsData, localStatus, dialogs, rooms, constraints) {
 
 		/*console.log("route", $route, $routeParams, $location);*/
 
@@ -86,29 +86,6 @@ define(['jquery', 'underscore', 'angular', 'bigscreen', 'moment', 'sjcl', 'moder
 
 		appData.set($scope);
 
-		var videoQualityMap = {
-			tiny: {
-				maxWidth: 80,
-				maxHeight: 45
-			},
-			low: {
-				maxWidth: 320,
-				maxHeight: 180
-			},
-			high: {
-				maxWidth: 640,
-				maxHeight: 360
-			},
-			hd: {
-				minWidth: 1280,
-				minHeight: 720
-			},
-			fullhd: {
-				minWidth: 1920,
-				minHeight: 1080
-			}
-		}
-
 		var displayName = safeDisplayName;
 
 		// Init STUN and TURN servers.
@@ -219,9 +196,10 @@ define(['jquery', 'underscore', 'angular', 'bigscreen', 'moment', 'sjcl', 'moder
 				console.warn("This is not a WebRTC capable browser.");
 				return;
 			}
+
 			var settings = $scope.master.settings;
 
-			// Create iceServers from scope settings.
+			// Create iceServers from scope.
 			var iceServers = [];
 			var iceServer;
 			if ($scope.stun.length) {
@@ -236,139 +214,13 @@ define(['jquery', 'underscore', 'angular', 'bigscreen', 'moment', 'sjcl', 'moder
 					iceServers.push.apply(iceServers, iceServer);
 				}
 			}
+			mediaStream.webrtc.settings.pcConfig.iceServers = iceServers;
 
-			var audioConstraints = [];
-			var videoConstraints = [];
-			var videoConstraintsMandatory = {};
-			var screensharingConstraints = [];
-
-			var pushmulti = function(arrays, data) {
-				_.each(arrays, function(a) {
-					a.push(data);
-				});
-			};
-
-			// Chrome only constraints.
-			if ($scope.isChrome) {
-				// Audio settings.
-				// For defaults in Chromium see https://code.google.com/p/webrtc/source/browse/trunk/talk/media/webrtc/webrtcvoiceengine.cc#225
-
-				// Experimental audio settings.
-				if (settings.experimental.enabled) {
-
-					audioConstraints.push({
-						googEchoCancellation: true // defaults to true
-					});
-					audioConstraints.push({
-						googEchoCancellation2: settings.experimental.audioEchoCancellation2 && true // defaults to false in Chrome
-					});
-					audioConstraints.push({
-						googAutoGainControl: true // defaults to true
-					});
-					audioConstraints.push({
-						googAutoGainControl2: settings.experimental.audioAutoGainControl2 && true // defaults to false in Chrome
-					});
-					audioConstraints.push({
-						googNoiseSuppression: true // defaults to true
-					});
-					audioConstraints.push({
-						googgNoiseSuppression2: settings.experimental.audioNoiseSuppression2 && true // defaults to false in Chrome
-					});
-					audioConstraints.push({
-						googHighpassFilter: true // defaults to true
-					});
-					audioConstraints.push({
-						googTypingNoiseDetection: settings.experimental.audioTypingNoiseDetection && true // defaults to true in Chrome
-					});
-
-				}
-
-				if ($scope.supported.renderToAssociatedSink) {
-					audioConstraints.push({
-						// When true uses the default communications device on Windows.
-						// https://codereview.chromium.org/155863003
-						googDucking: true // defaults to true on Windows.
-					});
-					audioConstraints.push({
-						// Chrome will start rendering mediastream output to an output device that's associated with
-						// the input stream that was opened via getUserMedia.
-						// https://chromiumcodereview.appspot.com/23558010
-						chromeRenderToAssociatedSink: settings.audioRenderToAssociatedSkin && true // defaults to false in Chrome
-					});
-				}
-
-				// Select microphone device by id.
-				if (settings.microphoneId) {
-					audioConstraints.push({
-						sourceId: settings.microphoneId
-					});
-				}
-				// Select camera by device id.
-				if (settings.cameraId) {
-					videoConstraints.push({
-						sourceId: settings.cameraId
-					});
-				}
-
-				// Video settings.
-				if (settings.experimental.enabled) {
-
-					// Experimental video settings.
-					pushmulti([videoConstraints, screensharingConstraints], {
-						// Changes the way the video encoding adapts to the available bandwidth.
-						// https://code.google.com/p/webrtc/issues/detail?id=3351
-						googLeakyBucket: settings.experimental.videoLeakyBucket && true // defaults to false in Chrome
-					});
-					pushmulti([videoConstraints, screensharingConstraints], {
-						// Removes the noise in the captured video stream at the expense of CPU.
-						googNoiseReduction: settings.experimental.videoNoiseReduction && true // defaults to false in Chrome
-					});
-					pushmulti([videoConstraints, screensharingConstraints], {
-						googCpuOveruseDetection: settings.experimental.videoCpuOveruseDetection && true // defaults to true in Chrome
-					});
-
-				}
-
-				// Video.
-				videoConstraintsMandatory = $.extend(videoConstraintsMandatory, videoQualityMap[settings.videoQuality]);
-				// Not supported as of Firefox 27.
-				if (settings.maxFrameRate && settings.maxFrameRate != "auto") {
-					videoConstraintsMandatory.maxFrameRate = parseInt(settings.maxFrameRate, 10);
-				}
-			}
-
-			// Apply the shit.
+			// Stereo.
 			mediaStream.webrtc.settings.stereo = settings.stereo;
-			mediaStream.webrtc.settings.mediaConstraints.video.mandatory = videoConstraintsMandatory;
-			mediaStream.webrtc.settings.mediaConstraints.video.optional = videoConstraints;
-			mediaStream.webrtc.settings.mediaConstraints.audio = {
-				optional: audioConstraints
-			};
-			mediaStream.webrtc.settings.pcConfig.iceServers = iceServers;
-			mediaStream.webrtc.settings.screensharing.mediaConstraints.video.optional = screensharingConstraints;
-
-			// Inject optional stuff.
-			var optionalPcConstraints = mediaStream.webrtc.settings.pcConstraints.optional = [];
-			if ($window.webrtcDetectedBrowser === "chrome") {
-				// NOTE(longsleep): We can always enable SCTP data channels, as we have a workaround
-				// using the "active" event for Firefox < 27.
-				// SCTP does not work correctly with Chrome 31. Require M32.
-				if ($window.webrtcDetectedVersion >= 32) {
-					// SCTP is supported from Chrome M31.
-					// No need to pass DTLS constraint as it is on by default in Chrome M31.
-					// For SCTP, reliable and ordered is true by default.
-				} else {
-					// Chrome < M32 does not yet do DTLS-SRTP by default whereas Firefox only
-					// does DTLS-SRTP. In order to get interop, you must supply Chrome
-					// with a PC constructor constraint to enable DTLS.
-					console.warn("Turning on SCTP combatibility - please update your Chrome.");
-					optionalPcConstraints.push({
-						DtlsSrtpKeyAgreement: true
-					});
-				}
-			}
 
-			//console.log("WebRTC settings", mediaStream.webrtc.settings);
+			// Refresh constraints.
+			constraints.refresh($scope.master.settings);
 
 		};
 		$scope.refreshWebrtcSettings(); // Call once for bootstrap.
diff --git a/static/js/directives/settings.js b/static/js/directives/settings.js
index b8dd5173..c734a0a7 100644
--- a/static/js/directives/settings.js
+++ b/static/js/directives/settings.js
@@ -20,9 +20,32 @@
  */
 define(['jquery', 'underscore', 'text!partials/settings.html'], function($, _, template) {
 
+	var videoQualityMap = {
+		tiny: {
+			maxWidth: 80,
+			maxHeight: 45
+		},
+		low: {
+			maxWidth: 320,
+			maxHeight: 180
+		},
+		high: {
+			maxWidth: 640,
+			maxHeight: 360
+		},
+		hd: {
+			minWidth: 1280,
+			minHeight: 720
+		},
+		fullhd: {
+			minWidth: 1920,
+			minHeight: 1080
+		}
+	};
+
 	return ["$compile", "mediaStream", function($compile, mediaStream) {
 
-		var controller = ['$scope', 'desktopNotify', 'mediaSources', 'safeApply', 'availableLanguages', 'translation', 'localStorage', 'userSettingsData', function($scope, desktopNotify, mediaSources, safeApply, availableLanguages, translation, localStorage, userSettingsData) {
+		var controller = ['$scope', 'desktopNotify', 'mediaSources', 'safeApply', 'availableLanguages', 'translation', 'localStorage', 'userSettingsData', 'constraints', function($scope, desktopNotify, mediaSources, safeApply, availableLanguages, translation, localStorage, userSettingsData, constraints) {
 
 			$scope.layout.settings = false;
 			$scope.showAdvancedSettings = true;
@@ -131,17 +154,88 @@ define(['jquery', 'underscore', 'text!partials/settings.html'], function($, _, t
 				}
 			});
 
-		}];
+			constraints.e.on("refresh", function(event, constraints) {
+
+				var settings = $scope.master.settings;
+
+				// Chrome only constraints.
+				if ($scope.isChrome) {
+
+					// For defaults in Chromium see https://code.google.com/p/webrtc/source/browse/trunk/talk/media/webrtc/webrtcvoiceengine.cc#225
+
+					// Experimental audio settings.
+					if (settings.experimental.enabled) {
+						constraints.add("audio", "googEchoCancellation", true); // defaults to true
+						constraints.add("audio", "googEchoCancellation2", settings.experimental.audioEchoCancellation2 && true); // defaults to false in Chrome
+						constraints.add("audio", "googAutoGainControl", true); // defaults to true
+						constraints.add("audio", "googAutoGainControl2", settings.experimental.audioAutoGainControl2 && true); // defaults to false in Chrome
+						constraints.add("audio", "googNoiseSuppression", true); // defaults to true
+						constraints.add("audio", "googgNoiseSuppression2", settings.experimental.audioNoiseSuppression2 && true); // defaults to false in Chrome
+						constraints.add("audio", "googHighpassFilter", true); // defaults to true
+						constraints.add("audio", "googTypingNoiseDetection", settings.experimental.audioTypingNoiseDetection && true); // defaults to true in Chrome
+					}
+
+					if ($scope.supported.renderToAssociatedSink) {
+						// When true uses the default communications device on Windows.
+						// https://codereview.chromium.org/155863003
+						constraints.add("audio", "googDucking", true); // defaults to true on Windows.
+						// Chrome will start rendering mediastream output to an output device that's associated with
+						// the input stream that was opened via getUserMedia.
+						// https://chromiumcodereview.appspot.com/23558010
+						constraints.add("audio", "chromeRenderToAssociatedSink", settings.audioRenderToAssociatedSkin && true); // defaults to false in Chrome
+					}
+
+					// Select microphone device by id.
+					if (settings.microphoneId) {
+						constraints.add("audio", "sourceId", settings.microphoneId);
+					}
+
+					// Select camera by device id.
+					if (settings.cameraId) {
+						constraints.add("video", "sourceId", settings.cameraId);
+					}
+
+					// Experimental video settings.
+					if (settings.experimental.enabled) {
+
+						// Changes the way the video encoding adapts to the available bandwidth.
+						// https://code.google.com/p/webrtc/issues/detail?id=3351
+						constraints.add(["video", "screensharing"], "googLeakyBucket", settings.experimental.videoLeakyBucket && true); // defaults to false in Chrome
+						// Removes the noise in the captured video stream at the expense of CPU.
+						constraints.add(["video", "screensharing"], "googNoiseReduction", settings.experimental.videoNoiseReduction && true); // defaults to false in Chrome
+						constraints.add(["video", "screensharing"], "googCpuOveruseDetection", settings.experimental.videoCpuOveruseDetection && true) // defaults to true in Chrome
 
-		var link = function($scope, $element) {};
+					}
+
+					// Set video quality.
+					var videoQuality = videoQualityMap[settings.videoQuality];
+					if (videoQuality) {
+						_.forEach(videoQuality, function(v, k) {
+							constraints.add("video", k, v, true);
+						});
+					}
+
+					// Set max frame rate if any was selected.
+					if (settings.maxFrameRate && settings.maxFrameRate != "auto") {
+						constraints.add("video", "maxFrameRate", parseInt(settings.maxFrameRate, 10), true);
+					}
+
+				} else {
+
+					// Other browsers constraints (there are none as of now.);
+
+				}
+
+			});
+
+		}];
 
 		return {
 			scope: true,
 			restrict: 'E',
 			replace: true,
 			template: template,
-			controller: controller,
-			link: link
+			controller: controller
 		};
 
 	}];
diff --git a/static/js/services/constraints.js b/static/js/services/constraints.js
new file mode 100644
index 00000000..86a4331d
--- /dev/null
+++ b/static/js/services/constraints.js
@@ -0,0 +1,134 @@
+/*
+ * Spreed WebRTC.
+ * Copyright (C) 2013-2014 struktur AG
+ *
+ * This file is part of Spreed WebRTC.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+ define(["jquery", "underscore"], function($, _) {
+
+	// constraints
+	return ["webrtc", "$window", function(webrtc, $window) {
+
+		var service = this;
+
+		var Constraints = function(settings) {
+			this.settings = _.clone(settings, true);
+			this.pc = [];
+			this.audio = [];
+			this.video = [];
+			this.videoMandatory = {};
+			this.screensharing =[];
+		};
+
+		Constraints.prototype.add = function(t, k, v, mandatory) {
+			if (_.isArray(t)) {
+				_.forEach(t, function(x) {
+					this.add(x, k, v, mandatory);
+				}, this);
+				return;
+			}
+			var obj;
+			if (mandatory) {
+				t = t + "Mandatory";
+			}
+			obj = this[t];
+			if (!obj) {
+				console.warn("Pushed to unknown constraint", t, k, v, mandatory);
+			} else {
+				if (mandatory) {
+					// Mandatory constraints are key/values.
+					obj[k] = v;
+				} else {
+					// Optional constraints are arrays.
+					var d = {};
+					d[k] = v;
+					obj.push(d)
+				}
+			}
+		};
+
+		Constraints.prototype.set = function(t, data, mandatory) {
+			if (mandatory) {
+				t = t + "Mandatory";
+			}
+			if (!this[t]) {
+				console.warn("Set to unknown constraint", t, data, mandatory);
+			} else {
+				this[t] = data;
+			}
+		};
+
+		service.e = $({}); // events
+
+		service.mediaConstraints = function(constraints) {
+			webrtc.settings.mediaConstraints.audio = {
+				optional: constraints.audio
+			};
+			webrtc.settings.mediaConstraints.video = {
+				optional: constraints.video,
+				mandatory: constraints.videoMandatory
+			};
+			webrtc.settings.screensharing.mediaConstraints.video.optional = constraints.screensharing;
+		};
+
+		service.pcConstraints = function(constraints) {
+			webrtc.settings.pcConstraints.optional = constraints.pc;
+		};
+
+		// Some default constraints.
+		service.e.on("refresh", function(event, constraints) {
+
+			if ($window.webrtcDetectedBrowser === "chrome") {
+				// NOTE(longsleep): We can always enable SCTP data channels, as we have a workaround
+				// using the "active" event for Firefox < 27.
+				// SCTP does not work correctly with Chrome 31. Require M32.
+				if ($window.webrtcDetectedVersion >= 32) {
+					// SCTP is supported from Chrome M31.
+					// No need to pass DTLS constraint as it is on by default in Chrome M31.
+					// For SCTP, reliable and ordered is true by default.
+				} else {
+					// Chrome < M32 does not yet do DTLS-SRTP by default whereas Firefox only
+					// does DTLS-SRTP. In order to get interop, you must supply Chrome
+					// with a PC constructor constraint to enable DTLS.
+					console.warn("Turning on SCTP combatibility - please update your Chrome.");
+					constraints.add("pc", "DtlsSrtpKeyAgreement", true);
+				}
+			}
+
+		});
+
+		// Public API.
+		return {
+			e: service.e,
+			refresh: function(settings) {
+				var constraints = new Constraints(settings);
+				service.e.triggerHandler("refresh", [constraints]);
+				service.mediaConstraints(constraints);
+				service.pcConstraints(constraints);
+			},
+			turn: function(turnData) {
+				// Set TURN server details.
+				service.turn = turnData;
+			},
+			stun: function(stunData) {
+				service.stun = stunData;
+			}
+		};
+
+	}];
+
+ });
\ No newline at end of file
diff --git a/static/js/services/services.js b/static/js/services/services.js
index b5a9975b..f9065458 100644
--- a/static/js/services/services.js
+++ b/static/js/services/services.js
@@ -62,7 +62,8 @@ define([
 	'services/localstatus',
 	'services/rooms',
 	'services/resturl',
-	'services/roompin'], function(_,
+	'services/roompin',
+	'services/constraints'], function(_,
 desktopNotify,
 playSound,
 safeApply,
@@ -104,7 +105,8 @@ userSettingsData,
 localStatus,
 rooms,
 restURL,
-roompin) {
+roompin,
+constraints) {
 
 	var services = {
 		desktopNotify: desktopNotify,
@@ -148,7 +150,8 @@ roompin) {
 		localStatus: localStatus,
 		rooms: rooms,
 		restURL: restURL,
-		roompin: roompin
+		roompin: roompin,
+		constraints: constraints
 	};
 
 	var initialize = function(angModule) {