Bug 1294154: Handle case where WMF is unable to determine time and duration. r=mattwoodrow

The WMF decoder doesn't handle well the case where a single frame was given to decode.
When draining, the output is a correctly decoded frame but with a time of 0 and a duration set at 1/30th.
This is a workaround

MozReview-Commit-ID: JbjgNmPXKIM

--HG--
extra : rebase_source : f25a1fd503678383265ec5053b41f3116ff52da0

dom/media/platforms/wmf/WMFMediaDataDecoder.h

@@ -37,12 +37,13 @@ public:
   virtual HRESULT Output(int64_t aStreamOffset,
                          RefPtr<MediaData>& aOutput) = 0;
 
-  void Flush() {
+  virtual void Flush()
+  {
     mDecoder->Flush();
     mSeekTargetThreshold.reset();
   }
 
-  void Drain()
+  virtual void Drain()
   {
     if (FAILED(mDecoder->SendMFTMessage(MFT_MESSAGE_COMMAND_DRAIN, 0))) {
       NS_WARNING("Failed to send DRAIN command to MFT");

dom/media/platforms/wmf/WMFVideoMFTManager.cpp

@@ -525,6 +525,8 @@ WMFVideoMFTManager::Input(MediaRawData* aSample)
   NS_ENSURE_TRUE(SUCCEEDED(hr) && mLastInput != nullptr, hr);
 
   mLastDuration = aSample->mDuration;
+  mLastTime = aSample->mTime;
+  mSamplesCount++;
 
   // Forward sample data to the decoder.
   return mDecoder->Input(mLastInput);
@@ -832,6 +834,15 @@ WMFVideoMFTManager::Output(int64_t aStreamOffset,
   HRESULT hr;
   aOutData = nullptr;
   int typeChangeCount = 0;
+  bool wasDraining = mDraining;
+  int64_t sampleCount = mSamplesCount;
+  if (wasDraining) {
+    mSamplesCount = 0;
+    mDraining = false;
+  }
+
+  media::TimeUnit pts;
+  media::TimeUnit duration;
 
   // Loop until we decode a sample, or an unexpected error that we can't
   // handle occurs.
@@ -873,12 +884,21 @@ WMFVideoMFTManager::Output(int64_t aStreamOffset,
         }
         continue;
       }
+      pts = GetSampleTime(sample);
+      duration = GetSampleDuration(sample);
+      if (!pts.IsValid() || !duration.IsValid()) {
+        return E_FAIL;
+      }
+      if (wasDraining && sampleCount == 1 && pts == media::TimeUnit()) {
+        // WMF is unable to calculate a duration if only a single sample
+        // was parsed. Additionally, the pts always comes out at 0 under those
+        // circumstances.
+        // Seeing that we've only fed the decoder a single frame, the pts
+        // and duration are known, it's of the last sample.
+        pts = media::TimeUnit::FromMicroseconds(mLastTime);
+        duration = media::TimeUnit::FromMicroseconds(mLastDuration);
+      }
       if (mSeekTargetThreshold.isSome()) {
-        media::TimeUnit pts = GetSampleTime(sample);
-		media::TimeUnit duration = GetSampleDuration(sample);
-        if (!pts.IsValid() || !duration.IsValid()) {
-          return E_FAIL;
-        }
         if ((pts + duration) < mSeekTargetThreshold.ref()) {
           LOG("Dropping video frame which pts is smaller than seek target.");
           // It is necessary to clear the pointer to release the previous output
@@ -907,6 +927,9 @@ WMFVideoMFTManager::Output(int64_t aStreamOffset,
   NS_ENSURE_TRUE(frame, E_FAIL);
 
   aOutData = frame;
+  // Set the potentially corrected pts and duration.
+  aOutData->mTime = pts.ToMicroseconds();
+  aOutData->mDuration = duration.ToMicroseconds();
 
   if (mNullOutputCount) {
     mGotValidOutputAfterNullOutput = true;

dom/media/platforms/wmf/WMFVideoMFTManager.h

@@ -49,6 +49,19 @@ public:
       ? "wmf hardware video decoder" : "wmf software video decoder";
   }
 
+  void Flush() override
+  {
+    MFTManager::Flush();
+    mDraining = false;
+    mSamplesCount = 0;
+  }
+
+  void Drain() override
+  {
+    MFTManager::Drain();
+    mDraining = true;
+  }
+
 private:
 
   bool ValidateVideoInfo();
@@ -81,6 +94,9 @@ private:
 
   RefPtr<IMFSample> mLastInput;
   float mLastDuration;
+  int64_t mLastTime = 0;
+  bool mDraining = false;
+  int64_t mSamplesCount = 0;
 
   bool mDXVAEnabled;
   const layers::LayersBackend mLayersBackend;