diff --git a/dom/media/MediaFormatReader.cpp b/dom/media/MediaFormatReader.cpp
index a4578f7c6fbf..62b671c76fac 100644
--- a/dom/media/MediaFormatReader.cpp
+++ b/dom/media/MediaFormatReader.cpp
@@ -380,10 +380,13 @@ MediaFormatReader::EnsureDecoderCreated(TrackType aTrack)
   MOZ_ASSERT(OnTaskQueue());
   MOZ_DIAGNOSTIC_ASSERT(!IsSuspended());
 
+  auto decoderCreatingError = "error creating decoder";
+  MediaResult result = MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR, decoderCreatingError);
   auto& decoder = GetDecoderData(aTrack);
 
   if (decoder.mDecoder) {
-    return NS_OK;
+    result = NS_OK;
+    return result;
   }
 
   if (!mPlatform) {
@@ -405,7 +408,8 @@ MediaFormatReader::EnsureDecoderCreated(TrackType aTrack)
         decoder.mTaskQueue,
         decoder.mCallback.get(),
         mCrashHelper,
-        decoder.mIsBlankDecode
+        decoder.mIsBlankDecode,
+        &result
       });
       break;
     }
@@ -420,19 +424,22 @@ MediaFormatReader::EnsureDecoderCreated(TrackType aTrack)
         mLayersBackendType,
         GetImageContainer(),
         mCrashHelper,
-        decoder.mIsBlankDecode
+        decoder.mIsBlankDecode,
+        &result
       });
       break;
     }
     default:
       break;
   }
-  if (decoder.mDecoder ) {
+  if (decoder.mDecoder) {
     decoder.mDescription = decoder.mDecoder->GetDescriptionName();
-    return NS_OK;
+    result = MediaResult(NS_OK);
+    return result;
   }
-  decoder.mDescription = "error creating decoder";
-  return MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR, "error creating decoder");
+
+  decoder.mDescription = decoderCreatingError;
+  return result;
 }
 
 bool
diff --git a/dom/media/platforms/PDMFactory.cpp b/dom/media/platforms/PDMFactory.cpp
index ee11eab2edfb..922ab4ae6756 100644
--- a/dom/media/platforms/PDMFactory.cpp
+++ b/dom/media/platforms/PDMFactory.cpp
@@ -83,7 +83,7 @@ StaticMutex PDMFactory::sMonitor;
 class SupportChecker
 {
 public:
-  enum class Result : uint8_t
+  enum class Reason : uint8_t
   {
     kSupported,
     kVideoFormatNotSupported,
@@ -91,6 +91,22 @@ public:
     kUnknown,
   };
 
+  struct CheckResult
+  {
+    explicit CheckResult(Reason aReason,
+                         MediaResult aResult = MediaResult(NS_OK))
+      : mReason(aReason),
+        mMediaResult(mozilla::Move(aResult))
+    {}
+    CheckResult(const CheckResult& aOther) = default;
+    CheckResult(CheckResult&& aOther) = default;
+    CheckResult& operator=(const CheckResult& aOther) = default;
+    CheckResult& operator=(CheckResult&& aOther) = default;
+
+    Reason mReason;
+    MediaResult mMediaResult;
+  };
+
   template<class Func>
   void
   AddToCheckList(Func&& aChecker)
@@ -113,30 +129,34 @@ public:
           // For consistency, all decoders should be checked.
           if (mp4_demuxer::H264::DecodeSPSFromExtraData(extraData, spsdata) &&
               spsdata.chroma_format_idc == PDMFactory::kYUV444) {
-            return SupportChecker::Result::kVideoFormatNotSupported;
+            return CheckResult(SupportChecker::Reason::kVideoFormatNotSupported,
+                               MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR,
+                                           RESULT_DETAIL("Decoder may not have the capability to handle"
+                                                         " the requested video format"
+                                                         " with YUV444 chroma subsampling.")));
           }
         }
-        return SupportChecker::Result::kSupported;
+        return CheckResult(SupportChecker::Reason::kSupported);
       });
     }
   }
 
-  SupportChecker::Result
+  SupportChecker::CheckResult
   Check()
   {
     for (auto& checker : mCheckerList) {
       auto result = checker();
-        if (result != SupportChecker::Result::kSupported) {
+        if (result.mReason != SupportChecker::Reason::kSupported) {
           return result;
       }
     }
-    return SupportChecker::Result::kSupported;
+    return CheckResult(SupportChecker::Reason::kSupported);
   }
 
   void Clear() { mCheckerList.Clear(); }
 
 private:
-  nsTArray<mozilla::function<SupportChecker::Result()>> mCheckerList;
+  nsTArray<mozilla::function<CheckResult()>> mCheckerList;
 }; // SupportChecker
 
 PDMFactory::PDMFactory()
@@ -229,20 +249,29 @@ PDMFactory::CreateDecoderWithPDM(PlatformDecoderModule* aPDM,
 {
   MOZ_ASSERT(aPDM);
   RefPtr<MediaDataDecoder> m;
+  MediaResult* result = aParams.mError;
 
   SupportChecker supportChecker;
   const TrackInfo& config = aParams.mConfig;
   supportChecker.AddMediaFormatChecker(config);
 
-  auto reason = supportChecker.Check();
-  if (reason != SupportChecker::Result::kSupported) {
+  auto checkResult = supportChecker.Check();
+  if (checkResult.mReason != SupportChecker::Reason::kSupported) {
     DecoderDoctorDiagnostics* diagnostics = aParams.mDiagnostics;
-    if (diagnostics) {
-      if (reason == SupportChecker::Result::kVideoFormatNotSupported) {
+    if (checkResult.mReason == SupportChecker::Reason::kVideoFormatNotSupported) {
+      if (diagnostics) {
         diagnostics->SetVideoNotSupported();
-      } else if (reason == SupportChecker::Result::kAudioFormatNotSupported) {
+      }
+      if (result) {
+        *result = checkResult.mMediaResult;
+      }
+    } else if (checkResult.mReason == SupportChecker::Reason::kAudioFormatNotSupported) {
+      if (diagnostics) {
         diagnostics->SetAudioNotSupported();
       }
+      if (result) {
+        *result = checkResult.mMediaResult;
+      }
     }
     return nullptr;
   }
@@ -253,6 +282,8 @@ PDMFactory::CreateDecoderWithPDM(PlatformDecoderModule* aPDM,
   }
 
   if (!config.IsVideo()) {
+    *result = MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR,
+                          RESULT_DETAIL("Decoder configuration error, expected audio or video."));
     return nullptr;
   }
 
diff --git a/dom/media/platforms/PlatformDecoderModule.h b/dom/media/platforms/PlatformDecoderModule.h
index 0f3877204c3c..a3f48b62c883 100644
--- a/dom/media/platforms/PlatformDecoderModule.h
+++ b/dom/media/platforms/PlatformDecoderModule.h
@@ -34,7 +34,7 @@ class CDMProxy;
 
 static LazyLogModule sPDMLog("PlatformDecoderModule");
 
-struct CreateDecoderParams {
+struct MOZ_STACK_CLASS CreateDecoderParams final {
   explicit CreateDecoderParams(const TrackInfo& aConfig)
     : mConfig(aConfig)
   {}
@@ -63,6 +63,7 @@ struct CreateDecoderParams {
   MediaDataDecoderCallback* mCallback = nullptr;
   DecoderDoctorDiagnostics* mDiagnostics = nullptr;
   layers::ImageContainer* mImageContainer = nullptr;
+  MediaResult* mError = nullptr;
   layers::LayersBackend mLayersBackend = layers::LayersBackend::LAYERS_NONE;
   RefPtr<GMPCrashHelper> mCrashHelper;
   bool mUseBlankDecoder = false;
@@ -72,6 +73,7 @@ private:
   void Set(MediaDataDecoderCallback* aCallback) { mCallback = aCallback; }
   void Set(DecoderDoctorDiagnostics* aDiagnostics) { mDiagnostics = aDiagnostics; }
   void Set(layers::ImageContainer* aImageContainer) { mImageContainer = aImageContainer; }
+  void Set(MediaResult* aError) { mError = aError; }
   void Set(layers::LayersBackend aLayersBackend) { mLayersBackend = aLayersBackend; }
   void Set(GMPCrashHelper* aCrashHelper) { mCrashHelper = aCrashHelper; }
   void Set(bool aUseBlankDecoder) { mUseBlankDecoder = aUseBlankDecoder; }