diff --git a/dom/media/platforms/wmf/WMFVideoMFTManager.cpp b/dom/media/platforms/wmf/WMFVideoMFTManager.cpp
index 9bcabad746e6..a589d8815eff 100644
--- a/dom/media/platforms/wmf/WMFVideoMFTManager.cpp
+++ b/dom/media/platforms/wmf/WMFVideoMFTManager.cpp
@@ -91,6 +91,7 @@ WMFVideoMFTManager::WMFVideoMFTManager(
   , mNullOutputCount(0)
   , mGotValidOutputAfterNullOutput(false)
   , mGotExcessiveNullOutput(false)
+  , mIsValid(true)
   // mVideoStride, mVideoWidth, mVideoHeight, mUseHwAccel are initialized in
   // Init().
 {
@@ -370,9 +371,33 @@ WMFVideoMFTManager::InitializeDXVA(bool aForceD3D9)
   return mDXVA2Manager != nullptr;
 }
 
+bool
+WMFVideoMFTManager::ValidateVideoInfo()
+{
+  // The WMF H.264 decoder is documented to have a minimum resolution
+  // 48x48 pixels. We've observed the decoder working for output smaller than
+  // that, but on some output it hangs in IMFTransform::ProcessOutput(), so
+  // we just reject streams which are less than the documented minimum.
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/dd797815(v=vs.85).aspx
+  static const int32_t MIN_H264_FRAME_DIMENSION = 48;
+  if (mStreamType == H264 &&
+      (mVideoInfo.mImage.width < MIN_H264_FRAME_DIMENSION ||
+       mVideoInfo.mImage.height < MIN_H264_FRAME_DIMENSION)) {
+    LogToBrowserConsole(NS_LITERAL_STRING(
+      "Can't decode H.264 stream with width or height less than 48 pixels."));
+    mIsValid = false;
+  }
+
+  return mIsValid;
+}
+
 bool
 WMFVideoMFTManager::Init()
 {
+  if (!ValidateVideoInfo()) {
+    return false;
+  }
+
   bool success = InitInternal(/* aForceD3D9 = */ false);
 
   if (success && mDXVA2Manager) {
@@ -484,6 +509,10 @@ WMFVideoMFTManager::SetDecoderMediaTypes()
 HRESULT
 WMFVideoMFTManager::Input(MediaRawData* aSample)
 {
+  if (!mIsValid) {
+    return E_FAIL;
+  }
+
   if (!mDecoder) {
     // This can happen during shutdown.
     return E_FAIL;
@@ -906,6 +935,7 @@ WMFVideoMFTManager::ConfigurationChanged(const TrackInfo& aConfig)
   MOZ_ASSERT(aConfig.GetAsVideoInfo());
   mVideoInfo = *aConfig.GetAsVideoInfo();
   mImageSize = mVideoInfo.mImage;
+  ValidateVideoInfo();
 }
 
 } // namespace mozilla
diff --git a/dom/media/platforms/wmf/WMFVideoMFTManager.h b/dom/media/platforms/wmf/WMFVideoMFTManager.h
index f8c6cc92551f..4a54a3be0f33 100644
--- a/dom/media/platforms/wmf/WMFVideoMFTManager.h
+++ b/dom/media/platforms/wmf/WMFVideoMFTManager.h
@@ -51,6 +51,8 @@ public:
 
 private:
 
+  bool ValidateVideoInfo();
+
   bool InitializeDXVA(bool aForceD3D9);
 
   bool InitInternal(bool aForceD3D9);
@@ -101,6 +103,7 @@ private:
   uint32_t mNullOutputCount;
   bool mGotValidOutputAfterNullOutput;
   bool mGotExcessiveNullOutput;
+  bool mIsValid;
 };
 
 } // namespace mozilla
diff --git a/dom/media/test/manifest.js b/dom/media/test/manifest.js
index a97005c57c25..cb57a6d3be79 100644
--- a/dom/media/test/manifest.js
+++ b/dom/media/test/manifest.js
@@ -533,6 +533,20 @@ var gErrorTests = [
   { name:"bogus.duh", type:"bogus/duh" }
 ];
 
+function IsWindowsVistaOrLater() {
+  var re = /Windows NT (\d+.\d)/;
+  var winver = manifestNavigator().userAgent.match(re);
+  return winver && winver.length == 2 && parseFloat(winver[1]) >= 6.0;
+}
+
+// Windows' H.264 decoder cannot handle H.264 streams with resolution
+// less than 48x48 pixels. We refuse to play and error on such streams.
+if (IsWindowsVistaOrLater() &&
+    manifestVideo().canPlayType('video/mp4; codecs="avc1.42E01E"')) {
+  gErrorTests = gErrorTests.concat({name: "red-46x48.mp4", type:"video/mp4"},
+                                   {name: "red-48x46.mp4", type:"video/mp4"});
+}
+
 // These are files that have nontrivial duration and are useful for seeking within.
 var gSeekTests = [
   { name:"r11025_s16_c1.wav", type:"audio/x-wav", duration:1.0 },
@@ -562,12 +576,6 @@ var gFastSeekTests = [
   { name:"bug516323.indexed.ogv", type:"video/ogg", keyframes:[0, 0.46, 3.06] },
 ];
 
-function IsWindows8OrLater() {
-  var re = /Windows NT (\d.\d)/;
-  var winver = manifestNavigator().userAgent.match(re);
-  return winver && winver.length == 2 && parseFloat(winver[1]) >= 6.2;
-}
-
 // These files are WebMs without cues. They're seekable within their buffered
 // ranges. If work renders WebMs fully seekable these files should be moved
 // into gSeekTests
diff --git a/dom/media/test/mochitest.ini b/dom/media/test/mochitest.ini
index 2c31abaace28..eaad3fc98910 100644
--- a/dom/media/test/mochitest.ini
+++ b/dom/media/test/mochitest.ini
@@ -491,6 +491,10 @@ support-files =
   r16000_u8_c1_list.wav
   r16000_u8_c1_list.wav^headers^
   reactivate_helper.html
+  red-46x48.mp4
+  red-46x48.mp4^headers^
+  red-48x46.mp4
+  red-48x46.mp4^headers^
   redirect.sjs
   referer.sjs
   region.vtt
diff --git a/dom/media/test/red-46x48.mp4 b/dom/media/test/red-46x48.mp4
new file mode 100644
index 000000000000..0760cc1c165d
Binary files /dev/null and b/dom/media/test/red-46x48.mp4 differ
diff --git a/dom/media/test/red-46x48.mp4^headers^ b/dom/media/test/red-46x48.mp4^headers^
new file mode 100644
index 000000000000..4030ea1d3ddb
--- /dev/null
+++ b/dom/media/test/red-46x48.mp4^headers^
@@ -0,0 +1 @@
+Cache-Control: no-store
diff --git a/dom/media/test/red-48x46.mp4 b/dom/media/test/red-48x46.mp4
new file mode 100644
index 000000000000..d83de4027d11
Binary files /dev/null and b/dom/media/test/red-48x46.mp4 differ
diff --git a/dom/media/test/red-48x46.mp4^headers^ b/dom/media/test/red-48x46.mp4^headers^
new file mode 100644
index 000000000000..4030ea1d3ddb
--- /dev/null
+++ b/dom/media/test/red-48x46.mp4^headers^
@@ -0,0 +1 @@
+Cache-Control: no-store