diff --git a/webrtc/RTCPeerConnection-tests.ts b/webrtc/RTCPeerConnection-tests.ts
index 3b35efad50..0b05fcdd88 100644
--- a/webrtc/RTCPeerConnection-tests.ts
+++ b/webrtc/RTCPeerConnection-tests.ts
@@ -1,10 +1,13 @@
 /// <reference path="MediaStream.d.ts" />
 /// <reference path="RTCPeerConnection.d.ts" />
 
-var config: RTCConfiguration = { iceServers: [{ url: "stun.l.google.com:19302" }] };
-var constraints: MediaConstraints = { mandatory: { OfferToReceiveAudio: true, OfferToReceiveVideo: true } };
+var config: RTCConfiguration =
+    { iceServers: [{ url: "stun.l.google.com:19302" }] };
+var constraints: RTCMediaConstraints =
+    { mandatory: { OfferToReceiveAudio: true, OfferToReceiveVideo: true } };
 
-var peerConnection: RTCPeerConnection = new RTCPeerConnection(config, constraints);
+var peerConnection: RTCPeerConnection =
+    new RTCPeerConnection(config, constraints);
 
 navigator.getUserMedia({ audio: true, video: true },
   stream => {
@@ -41,11 +44,15 @@ peerConnection.setRemoteDescription(sessionDescription, () => {
     answer => {
       peerConnection.setLocalDescription(answer,
         () => console.log('Set local description'),
-      error => console.log("Error setting local description from created answer: " + error + "; answer.sdp=" + answer.sdp));
+      error => console.log(
+          "Error setting local description from created answer: " + error +
+          "; answer.sdp=" + answer.sdp));
     },
   error => console.log("Error creating answer: " + error));
 },
-error => console.log('Error setting remote description: ' + error + "; offer.sdp=" + offer.sdp));
+error => console.log('Error setting remote description: ' + error +
+    "; offer.sdp=" + offer.sdp));
 
-var wkPeerConnection: webkitRTCPeerConnection = new webkitRTCPeerConnection(config, constraints);
+var wkPeerConnection: webkitRTCPeerConnection =
+    new webkitRTCPeerConnection(config, constraints);
 
diff --git a/webrtc/RTCPeerConnection.d.ts b/webrtc/RTCPeerConnection.d.ts
index bc2c6205da..e0e75ad61e 100644
--- a/webrtc/RTCPeerConnection.d.ts
+++ b/webrtc/RTCPeerConnection.d.ts
@@ -43,7 +43,7 @@ interface mozRTCPeerConnection extends RTCPeerConnection {
 declare var mozRTCPeerConnection: {
   prototype: mozRTCPeerConnection;
   new (settings: RTCPeerConnectionConfig,
-       constraints?:MediaConstraints): mozRTCPeerConnection;
+       constraints?:RTCMediaConstraints): mozRTCPeerConnection;
 }
 // webkit (Chrome) specific prefixes.
 interface webkitRTCPeerConnection extends RTCPeerConnection {
@@ -51,12 +51,12 @@ interface webkitRTCPeerConnection extends RTCPeerConnection {
 declare var webkitRTCPeerConnection: {
   prototype: webkitRTCPeerConnection;
   new (settings: RTCPeerConnectionConfig,
-       constraints?:MediaConstraints): webkitRTCPeerConnection;
+       constraints?:RTCMediaConstraints): webkitRTCPeerConnection;
 }
 
 // For Chrome, look at the code here:
 // https://code.google.com/p/chromium/codesearch#chromium/src/third_party/libjingle/source/talk/app/webrtc/webrtcsession.cc&sq=package:chromium&dr=C&l=63
-interface OptionalMediaConstraint {
+interface RTCOptionalMediaConstraint {
   // When true, will use DTLS/SCTP data channels
   DtlsSrtpKeyAgreement?: boolean;
   // When true will use Rtp-based data channels (depreicated)
@@ -65,12 +65,12 @@ interface OptionalMediaConstraint {
 
 // ks 12/20/12 - There's more here that doesn't seem to be documented very well yet.
 // http://www.w3.org/TR/2013/WD-webrtc-20130910/
-interface MediaConstraints {
-  mandatory?: MediaOfferConstraints;
-  optional?: OptionalMediaConstraint[]
+interface RTCMediaConstraints {
+  mandatory?: RTCMediaOfferConstraints;
+  optional?: RTCOptionalMediaConstraint[]
 }
 
-interface MediaOfferConstraints {
+interface RTCMediaOfferConstraints {
   OfferToReceiveAudio: boolean;
   OfferToReceiveVideo: boolean;
 }
@@ -215,10 +215,10 @@ declare enum RTCSignalingState {
 interface RTCPeerConnection {
   createOffer(successCallback: RTCSessionDescriptionCallback,
               failureCallback?: RTCPeerConnectionErrorCallback,
-              constraints?: MediaConstraints): void;
+              constraints?: RTCMediaConstraints): void;
   createAnswer(successCallback: RTCSessionDescriptionCallback,
                failureCallback?: RTCPeerConnectionErrorCallback,
-               constraints?: MediaConstraints): void;
+               constraints?: RTCMediaConstraints): void;
   setLocalDescription(description: RTCSessionDescription,
                       successCallback?: RTCVoidCallback,
                       failureCallback?: RTCPeerConnectionErrorCallback): void;
@@ -229,7 +229,7 @@ interface RTCPeerConnection {
   remoteDescription: RTCSessionDescription;
   signalingState: string; // RTCSignalingState; see TODO(1)
   updateIce(configuration?: RTCConfiguration,
-            constraints?: MediaConstraints): void;
+            constraints?: RTCMediaConstraints): void;
   addIceCandidate(candidate: RTCIceCandidate): void;
   iceGatheringState: string;  // RTCIceGatheringState; see TODO(1)
   iceConnectionState: string;  // RTCIceConnectionState; see TODO(1)
@@ -238,7 +238,7 @@ interface RTCPeerConnection {
   createDataChannel(label?: string,
                     dataChannelDict?: RTCDataChannelInit): RTCDataChannel;
   ondatachannel: (event: Event) => void;
-  addStream(stream: MediaStream, constraints?: MediaConstraints): void;
+  addStream(stream: MediaStream, constraints?: RTCMediaConstraints): void;
   removeStream(stream: MediaStream): void;
   close(): void;
   onnegotiationneeded: (event: Event) => void;
@@ -255,7 +255,7 @@ interface RTCPeerConnection {
 declare var RTCPeerConnection: {
   prototype: RTCPeerConnection;
   new (configuration: RTCConfiguration,
-       constraints?: MediaConstraints): RTCPeerConnection;
+       constraints?: RTCMediaConstraints): RTCPeerConnection;
 }
 
 interface RTCIceCandidate {