b=811730 - Take skip into account when copying video frames into shared memory. r=cpeterson

gfx/layers/ipc/ImageContainerChild.cpp

@@ -135,9 +135,11 @@ bool ImageContainerChild::CopyDataIntoSharedImage(Image* src, SharedImage* dest)
 
     ShmemYCbCrImage shmemImage(yuv.data(), yuv.offset());
 
+    MOZ_ASSERT(data->mCbSkip == data->mCrSkip);
     if (!shmemImage.CopyData(data->mYChannel, data->mCbChannel, data->mCrChannel,
                              data->mYSize, data->mYStride,
-                             data->mCbCrSize, data->mCbCrStride)) {
+                             data->mCbCrSize, data->mCbCrStride,
+                             data->mYSkip, data->mCbSkip)) {
       NS_WARNING("Failed to copy image data!");
       return false;
     }
@@ -515,10 +517,11 @@ public:
     mSize = mData.mPicSize;
 
     ShmemYCbCrImage shmImg(mShmem);
-
+    MOZ_ASSERT(aData.mCbSkip == aData.mCrSkip);
     if (!shmImg.CopyData(aData.mYChannel, aData.mCbChannel, aData.mCrChannel,
                          aData.mYSize, aData.mYStride,
-                         aData.mCbCrSize, aData.mCbCrStride)) {
+                         aData.mCbCrSize, aData.mCbCrStride,
+                         aData.mYSkip, aData.mCbSkip)) {
       NS_WARNING("Failed to copy image data!");
     }
     mData.mYChannel = shmImg.GetYData();

gfx/layers/ipc/ShmemYCbCrImage.cpp

@@ -150,25 +150,54 @@ bool ShmemYCbCrImage::IsValid()
   return true;
 }
 
-bool ShmemYCbCrImage::CopyData(uint8_t* aYData, uint8_t* aCbData, uint8_t* aCrData,
+static void CopyLineWithSkip(const uint8_t* src, uint8_t* dst, uint32_t len, uint32_t skip) {
+  for (uint32_t i = 0; i < len; ++i) {
+    *dst = *src;
+    src += 1 + skip;
+    ++dst;
+  }
+}
+
+bool ShmemYCbCrImage::CopyData(const uint8_t* aYData,
+                               const uint8_t* aCbData, const uint8_t* aCrData,
                                gfxIntSize aYSize, uint32_t aYStride,
-                               gfxIntSize aCbCrSize, uint32_t aCbCrStride)
+                               gfxIntSize aCbCrSize, uint32_t aCbCrStride,
+                               uint32_t aYSkip, uint32_t aCbCrSkip)
 {
   if (!IsValid() || GetYSize() != aYSize || GetCbCrSize() != aCbCrSize) {
     return false;
   }
-  for (int i = 0; i < aYSize.height; i++) {
-    memcpy(GetYData() + i * GetYStride(),
-           aYData + i * aYStride,
-           aYSize.width);
+  for (int i = 0; i < aYSize.height; ++i) {
+    if (aYSkip == 0) {
+      // fast path
+      memcpy(GetYData() + i * GetYStride(),
+             aYData + i * aYStride,
+             aYSize.width);
+    } else {
+      // slower path
+      CopyLineWithSkip(aYData + i * aYStride,
+                       GetYData() + i * GetYStride(),
+                       aYSize.width, aYSkip);
+    }
   }
-  for (int i = 0; i < aCbCrSize.height; i++) {
-    memcpy(GetCbData() + i * GetCbCrStride(),
-           aCbData + i * aCbCrStride,
-           aCbCrSize.width);
-    memcpy(GetCrData() + i * GetCbCrStride(),
-           aCrData + i * aCbCrStride,
-           aCbCrSize.width);
+  for (int i = 0; i < aCbCrSize.height; ++i) {
+    if (aCbCrSkip == 0) {
+      // fast path
+      memcpy(GetCbData() + i * GetCbCrStride(),
+             aCbData + i * aCbCrStride,
+             aCbCrSize.width);
+      memcpy(GetCrData() + i * GetCbCrStride(),
+             aCrData + i * aCbCrStride,
+             aCbCrSize.width);
+    } else {
+      // slower path
+      CopyLineWithSkip(aCbData + i * aCbCrStride,
+                       GetCbData() + i * GetCbCrStride(),
+                       aCbCrSize.width, aCbCrSkip);
+      CopyLineWithSkip(aCrData + i * aCbCrStride,
+                       GetCrData() + i * GetCbCrStride(),
+                       aCbCrSize.width, aCbCrSkip);
+    }
   }
   return true;
 }

gfx/layers/ipc/ShmemYCbCrImage.h

@@ -96,9 +96,11 @@ public:
   /**
    * Copies the data passed in parameter into the shmem.
    */
-  bool CopyData(uint8_t* aYData, uint8_t* aCbData, uint8_t* aCrData,
+  bool CopyData(const uint8_t* aYData,
+                const uint8_t* aCbData, const uint8_t* aCrData,
                 gfxIntSize aYSize, uint32_t aYStride,
-                gfxIntSize aCbCrSize, uint32_t aCbCrStride);
+                gfxIntSize aCbCrSize, uint32_t aCbCrStride,
+                uint32_t aYSkip, uint32_t aCbCrSkip);
 
 private:
   bool Open(Shmem& aShmem, size_t aOffset = 0);