Bug 1144523 - Convert input buffer to expected format for OpenH264 GMP plugin. r=cpearce

dom/media/fmp4/gmp/GMPVideoDecoder.cpp

@@ -6,6 +6,7 @@
 
 #include "GMPVideoDecoder.h"
 #include "GMPVideoHost.h"
+#include "mozilla/Endian.h"
 #include "prsystem.h"
 
 namespace mozilla {
@@ -132,13 +133,26 @@ GMPVideoDecoder::CreateFrame(mp4_demuxer::MP4Sample* aSample)
 
   memcpy(frame->Buffer(), aSample->data, frame->Size());
 
+  // Convert 4-byte NAL unit lengths to host-endian 4-byte buffer lengths to
+  // suit the GMP API.
+  if (mConvertNALUnitLengths) {
+    const int kNALLengthSize = 4;
+    uint8_t* buf = frame->Buffer();
+    while (buf < frame->Buffer() + frame->Size() - kNALLengthSize) {
+      uint32_t length = BigEndian::readUint32(buf) + kNALLengthSize;
+      *reinterpret_cast<uint32_t *>(buf) = length;
+      buf += length;
+    }
+  }
+
+  frame->SetBufferType(GMP_BufferLength32);
+
   frame->SetEncodedWidth(mConfig.display_width);
   frame->SetEncodedHeight(mConfig.display_height);
   frame->SetTimeStamp(aSample->composition_timestamp);
   frame->SetCompleteFrame(true);
   frame->SetDuration(aSample->duration);
   frame->SetFrameType(aSample->is_sync_point ? kGMPKeyFrame : kGMPDeltaFrame);
-  frame->SetBufferType(GMP_BufferLength32);
 
   return frame;
 }
@@ -157,6 +171,16 @@ GMPVideoDecoder::Init()
   NS_ENSURE_SUCCESS(rv, rv);
   MOZ_ASSERT(mHost && mGMP);
 
+  // GMP implementations have interpreted the meaning of GMP_BufferLength32
+  // differently.  The OpenH264 GMP expects GMP_BufferLength32 to behave as
+  // specified in the GMP API, where each buffer is prefixed by a 32-bit
+  // host-endian buffer length that includes the size of the buffer length
+  // field.  Other existing GMPs currently expect GMP_BufferLength32 (when
+  // combined with kGMPVideoCodecH264) to mean "like AVCC but restricted to
+  // 4-byte NAL lengths" (i.e. buffer lengths are specified in big-endian
+  // and do not include the length of the buffer length field.
+  mConvertNALUnitLengths = mGMP->GetDisplayName().EqualsLiteral("gmpopenh264");
+
   GMPVideoCodec codec;
   memset(&codec, 0, sizeof(codec));
 

dom/media/fmp4/gmp/GMPVideoDecoder.h

@@ -62,6 +62,7 @@ protected:
    , mGMP(nullptr)
    , mHost(nullptr)
    , mAdapter(aAdapter)
+   , mConvertNALUnitLengths(false)
   {
   }
 
@@ -79,6 +80,7 @@ public:
                                        VideoInfo(aConfig.display_width,
                                                  aConfig.display_height),
                                        aImageContainer))
+   , mConvertNALUnitLengths(false)
   {
   }
 
@@ -100,9 +102,9 @@ private:
   GMPVideoDecoderProxy* mGMP;
   GMPVideoHost* mHost;
   nsAutoPtr<VideoCallbackAdapter> mAdapter;
+  bool mConvertNALUnitLengths;
 };
 
-
 } // namespace mozilla
 
 #endif // GMPVideoDecoder_h_

dom/media/gmp/GMPParent.cpp

@@ -1002,6 +1002,12 @@ GMPParent::SetNodeId(const nsACString& aNodeId)
   mNodeId = aNodeId;
 }
 
+const nsCString&
+GMPParent::GetDisplayName() const
+{
+  return mDisplayName;
+}
+
 const nsCString&
 GMPParent::GetVersion() const
 {

dom/media/gmp/GMPParent.h

@@ -115,6 +115,7 @@ public:
   void SetNodeId(const nsACString& aNodeId);
   const nsACString& GetNodeId() const { return mNodeId; }
 
+  const nsCString& GetDisplayName() const;
   const nsCString& GetVersion() const;
 
   // Returns true if a plugin can be or is being used across multiple NodeIds.

dom/media/gmp/GMPVideoDecoderParent.cpp

@@ -182,6 +182,18 @@ GMPVideoDecoderParent::Drain()
   return NS_OK;
 }
 
+const nsCString&
+GMPVideoDecoderParent::GetDisplayName() const
+{
+  if (!mIsOpen) {
+    NS_WARNING("Trying to use an dead GMP video decoder");
+  }
+
+  MOZ_ASSERT(mPlugin->GMPThread() == NS_GetCurrentThread());
+
+  return mPlugin->GetDisplayName();
+}
+
 // Note: Consider keeping ActorDestroy sync'd up when making changes here.
 nsresult
 GMPVideoDecoderParent::Shutdown()

dom/media/gmp/GMPVideoDecoderParent.h

@@ -45,6 +45,7 @@ public:
   virtual nsresult Reset() MOZ_OVERRIDE;
   virtual nsresult Drain() MOZ_OVERRIDE;
   virtual const uint64_t ParentID() MOZ_OVERRIDE { return reinterpret_cast<uint64_t>(mPlugin.get()); }
+  virtual const nsCString& GetDisplayName() const MOZ_OVERRIDE;
 
   // GMPSharedMemManager
   virtual bool Alloc(size_t aSize, Shmem::SharedMemory::SharedMemoryType aType, Shmem* aMem) MOZ_OVERRIDE

dom/media/gmp/GMPVideoDecoderProxy.h

@@ -49,6 +49,8 @@ public:
   // Call to tell GMP/plugin the consumer will no longer use this
   // interface/codec.
   virtual void Close() = 0;
+
+  virtual const nsCString& GetDisplayName() const = 0;
 };
 
 #endif