--- a/media/webrtc/signaling/src/jsep/JsepTrack.cpp
+++ b/media/webrtc/signaling/src/jsep/JsepTrack.cpp
@@ -289,16 +289,18 @@ JsepTrack::CreateEncodings(
     // If we end up supporting params for rid, we would handle that here.
 
     // Incorporate the corresponding JS encoding constraints, if they exist
     for (const JsConstraints& jsConstraints : mJsEncodeConstraints) {
       if (jsConstraints.rid == rids[i].id) {
         encoding->mConstraints = jsConstraints.constraints;
       }
     }
+
+    encoding->UpdateMaxBitrate(remote);
   }
 }
 
 std::vector<JsepCodecDescription*>
 JsepTrack::GetCodecClones() const
 {
   std::vector<JsepCodecDescription*> clones;
   for (const JsepCodecDescription* codec : mPrototypeCodecs.values) {

--- a/media/webrtc/signaling/src/jsep/JsepTrackEncoding.h
+++ b/media/webrtc/signaling/src/jsep/JsepTrackEncoding.h
@@ -34,16 +34,24 @@ public:
     for (const JsepCodecDescription* codec : mCodecs.values) {
       if (codec->mDefaultPt == format) {
         return true;
       }
     }
     return false;
   }
 
+  void UpdateMaxBitrate(const SdpMediaSection& remote)
+  {
+    uint32_t tias = remote.GetBandwidth("TIAS");
+    mConstraints.maxBr = std::min(tias? tias:mConstraints.maxBr,
+                                  mConstraints.maxBr? mConstraints.maxBr:tias);
+    // TODO do we want b=AS support?  I don't think so
+  }
+
   EncodingConstraints mConstraints;
   std::string mRid;
 
 private:
   PtrVector<JsepCodecDescription> mCodecs;
 };
 }
 

--- a/media/webrtc/signaling/src/media-conduit/VideoConduit.cpp
+++ b/media/webrtc/signaling/src/media-conduit/VideoConduit.cpp
@@ -1041,23 +1041,23 @@ WebrtcVideoConduit::SelectBitrates(unsig
 
   // mLastFramerateTenths is an atomic, and scaled by *10
   double framerate = std::min((aLastFramerateTenths/10.),60.0);
   MOZ_ASSERT(framerate > 0);
   // Now linear reduction/increase based on fps (max 60fps i.e. doubling)
   if (framerate >= 10) {
     out_min = out_min * (framerate/30);
     out_start = out_start * (framerate/30);
-    out_max = out_max * (framerate/30);
+    out_max = std::max((unsigned int)(out_max * (framerate/30)), cap);
   } else {
     // At low framerates, don't reduce bandwidth as much - cut slope to 1/2.
     // Mostly this would be ultra-low-light situations/mobile or screensharing.
     out_min = out_min * ((10-(framerate/2))/30);
     out_start = out_start * ((10-(framerate/2))/30);
-    out_max = out_max * ((10-(framerate/2))/30);
+    out_max = std::max((unsigned int)(out_max * ((10-(framerate/2))/30)), cap);
   }
 
   if (mMinBitrate && mMinBitrate > out_min) {
     out_min = mMinBitrate;
   }
   // If we try to set a minimum bitrate that is too low, ViE will reject it.
   out_min = std::max((unsigned int) webrtc::kViEMinCodecBitrate,
                                   out_min);