Bug 1002320 - Switch video readers at the earliest possible point rather than the latest. r=cajbir

content/media/mediasource/MediaSourceDecoder.cpp

@@ -88,6 +88,11 @@ public:
       MOZ_ASSERT(mPendingDecoders.IsEmpty());
       return false;
     }
+
+    if (MaybeSwitchVideoReaders(aTimeThreshold)) {
+      GetVideoReader()->DecodeToTarget(aTimeThreshold);
+    }
+
     bool rv = GetVideoReader()->DecodeVideoFrame(aKeyFrameSkip, aTimeThreshold);
 
     nsAutoTArray<VideoData*, 10> video;
@@ -103,16 +108,6 @@ public:
 
     MSE_DEBUG("%p MSR::DecodeVF %d (%p) returned false (readers=%u)",
               this, mActiveVideoDecoder, mDecoders[mActiveVideoDecoder].get(), mDecoders.Length());
-    if (SwitchVideoReaders(aTimeThreshold)) {
-      rv = GetVideoReader()->DecodeVideoFrame(aKeyFrameSkip, aTimeThreshold);
-
-      nsAutoTArray<VideoData*, 10> video;
-      GetVideoReader()->VideoQueue().GetElementsAfter(-1, &video);
-      for (uint32_t i = 0; i < video.Length(); ++i) {
-        VideoQueue().Push(video[i]);
-      }
-      GetVideoReader()->VideoQueue().Empty();
-    }
     return rv;
   }
 
@@ -136,14 +131,9 @@ public:
   void CallDecoderInitialization();
 
 private:
-  bool SwitchVideoReaders(int64_t aTimeThreshold) {
-    MOZ_ASSERT(mActiveVideoDecoder != -1);
-    // XXX: We switch when the first reader is depleted, but it might be
-    // better to switch as soon as the next reader is ready to decode and
-    // has data for the current media time.
+  bool MaybeSwitchVideoReaders(int64_t aTimeThreshold) {
     ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
-
-    GetVideoReader()->SetIdle();
+    MOZ_ASSERT(mActiveVideoDecoder != -1);
 
     WaitForPendingDecoders();
 
@@ -151,14 +141,17 @@ private:
       if (!mDecoders[i]->GetReader()->GetMediaInfo().HasVideo()) {
         continue;
       }
-      mActiveVideoDecoder = i;
-      MSE_DEBUG("%p MSR::DecodeVF switching to %d", this, mActiveVideoDecoder);
+      if (aTimeThreshold >= mDecoders[i]->GetMediaStartTime()) {
+        GetVideoReader()->SetIdle();
 
-      GetVideoReader()->SetActive();
-      GetVideoReader()->DecodeToTarget(aTimeThreshold);
+        mActiveVideoDecoder = i;
+        MSE_DEBUG("%p MSR::DecodeVF switching to %d", this, mActiveVideoDecoder);
 
-      return true;
+        GetVideoReader()->SetActive();
+        return true;
+      }
     }
+
     return false;
   }
 
@@ -337,9 +330,13 @@ MediaSourceReader::CallDecoderInitialization()
     MediaInfo mi;
     nsAutoPtr<MetadataTags> tags; // TODO: Handle metadata.
     nsresult rv;
+    int64_t startTime = 0;
     {
       ReentrantMonitorAutoExit exitMon(mDecoder->GetReentrantMonitor());
       rv = reader->ReadMetadata(&mi, getter_Transfers(tags));
+      if (NS_SUCCEEDED(rv)) {
+        reader->FindStartTime(startTime);
+      }
     }
     reader->SetIdle();
     if (NS_FAILED(rv)) {
@@ -347,10 +344,12 @@ MediaSourceReader::CallDecoderInitialization()
       MSE_DEBUG("%p: Reader %p failed to initialize, rv=%x", this, reader, rv);
       continue;
     }
+    decoder->SetMediaStartTime(startTime);
 
     bool active = false;
     if (mi.HasVideo() || mi.HasAudio()) {
-      MSE_DEBUG("%p: Reader %p has video=%d audio=%d", this, reader, mi.HasVideo(), mi.HasAudio());
+      MSE_DEBUG("%p: Reader %p has video=%d audio=%d startTime=%lld",
+                this, reader, mi.HasVideo(), mi.HasAudio(), startTime);
       active = true;
     }
 

content/media/mediasource/SourceBuffer.cpp

@@ -196,16 +196,10 @@ SourceBuffer::GetBuffered(ErrorResult& aRv)
     nsRefPtr<TimeRanges> r = new TimeRanges();
     mDecoders[i]->GetBuffered(r);
     if (r->Length() > 0) {
-      MSE_DEBUG("%p GetBuffered decoder=%u Length=%u Start=%f End=%f", this, i, r->Length(),
-                r->GetStartTime(), r->GetEndTime());
       ranges->Add(r->GetStartTime(), r->GetEndTime());
-    } else {
-      MSE_DEBUG("%p GetBuffered decoder=%u Length=%u", this, i, r->Length());
     }
   }
   ranges->Normalize();
-  MSE_DEBUG("%p GetBuffered Length=%u Start=%f End=%f", this, ranges->Length(),
-            ranges->GetStartTime(), ranges->GetEndTime());
   return ranges.forget();
 }
 

content/media/mediasource/SubBufferDecoder.h

@@ -21,6 +21,7 @@ public:
   // of the caller to manage the memory of the MediaResource object.
   SubBufferDecoder(MediaResource* aResource, MediaSourceDecoder* aParentDecoder)
     : BufferDecoder(aResource), mParentDecoder(aParentDecoder), mReader(nullptr)
+    , mMediaDuration(-1), mMediaStartTime(0)
   {
   }
 
@@ -72,10 +73,21 @@ public:
     return mMediaDuration;
   }
 
+  int64_t GetMediaStartTime()
+  {
+    return mMediaStartTime;
+  }
+
+  void SetMediaStartTime(int64_t aMediaStartTime)
+  {
+    mMediaStartTime = aMediaStartTime;
+  }
+
 private:
   MediaSourceDecoder* mParentDecoder;
   nsAutoPtr<MediaDecoderReader> mReader;
   int64_t mMediaDuration;
+  int64_t mMediaStartTime;
 };
 
 } // namespace mozilla