--- a/gfx/layers/ImageLayers.h
+++ b/gfx/layers/ImageLayers.h
@@ -214,19 +214,16 @@ protected:
  * 4:2:0 - CbCr width and height is half that of Y.
  *
  * The color format is detected based on the height/width ratios
  * defined above.
  * 
  * The Image that is rendered is the picture region defined by
  * mPicX, mPicY and mPicSize. The size of the rendered image is
  * mPicSize, not mYSize or mCbCrSize.
- * 
- * Note: The color-conversion code does not currently support 4:4:4
- * and an error is raised in this case. See bug 551378.
  */
 class THEBES_API PlanarYCbCrImage : public Image {
 public:
   struct Data {
     // Luminance buffer
     PRUint8* mYChannel;
     PRInt32 mYStride;
     gfxIntSize mYSize;

--- a/gfx/layers/basic/BasicImages.cpp
+++ b/gfx/layers/basic/BasicImages.cpp
@@ -130,17 +130,17 @@ BasicPlanarYCbCrImage::SetData(const Dat
   if (!mBuffer) {
     // out of memory
     return;
   }
 
   gfx::YUVType type = gfx::YV12;
   if (aData.mYSize.width == aData.mCbCrSize.width &&
       aData.mYSize.height == aData.mCbCrSize.height) {
-    NS_ERROR("YCbCr 4:4:4 format not supported");
+    type = gfx::YV24;
   }
   else if (aData.mYSize.width / 2 == aData.mCbCrSize.width &&
            aData.mYSize.height == aData.mCbCrSize.height) {
     type = gfx::YV16;
   }
   else if (aData.mYSize.width / 2 == aData.mCbCrSize.width &&
            aData.mYSize.height / 2 == aData.mCbCrSize.height ) {
     type = gfx::YV12;

--- a/gfx/ycbcr/README
+++ b/gfx/ycbcr/README
@@ -10,8 +10,10 @@ convert.patch: Change Chromium code to b
                Add runtime CPU detection for MMX
                Move default C implementation to work on all platforms.
 
 picture_region.patch: Change Chromium code to allow a picture region.
                       The YUV conversion will convert within this 
                       picture region only.
 
 remove_scale.patch: Removes Chromium scaling code.
+
+yv24.patch: Adds YCbCr 4:4:4 support

--- a/gfx/ycbcr/update.sh
+++ b/gfx/ycbcr/update.sh
@@ -4,8 +4,9 @@ cp $1/media/base/yuv_convert.cc yuv_conv
 cp $1/media/base/yuv_row.h .
 cp $1/media/base/yuv_row_linux.cc yuv_row_linux.cpp
 cp $1/media/base/yuv_row_mac.cc yuv_row_mac.cpp
 cp $1/media/base/yuv_row_win.cc yuv_row_win.cpp
 cp $1/media/base/yuv_row_linux.cc yuv_row_c.cpp
 patch -p3 <convert.patch
 patch -p3 <picture_region.patch
 patch -p3 <remove_scale.patch
+patch -p3 <yv24.patch

--- a/gfx/ycbcr/yuv_convert.cpp
+++ b/gfx/ycbcr/yuv_convert.cpp
@@ -6,16 +6,17 @@
 // http://www.fourcc.org/yuv.php
 // The actual conversion is best described here
 // http://en.wikipedia.org/wiki/YUV
 // An article on optimizing YUV conversion using tables instead of multiplies
 // http://lestourtereaux.free.fr/papers/data/yuvrgb.pdf
 //
 // YV12 is a full plane of Y and a half height, half width chroma planes
 // YV16 is a full plane of Y and a full height, half width chroma planes
+// YV24 is a full plane of Y and a full height, full width chroma planes
 //
 // ARGB pixel format is output, which on little endian is stored as BGRA.
 // The alpha is set to 255, allowing the application to use RGBA or RGB32.
 
 #include "yuv_convert.h"
 
 // Header for low level row functions.
 #include "yuv_row.h"
@@ -33,50 +34,55 @@ void ConvertYCbCrToRGB32(const uint8* y_
                          int pic_x,
                          int pic_y,
                          int pic_width,
                          int pic_height,
                          int y_pitch,
                          int uv_pitch,
                          int rgb_pitch,
                          YUVType yuv_type) {
-  unsigned int y_shift = yuv_type;
-  bool has_mmx = supports_mmx();
-  bool odd_pic_x = pic_x % 2 != 0;
+  unsigned int y_shift = yuv_type == YV12 ? 1 : 0;
+  unsigned int x_shift = yuv_type == YV24 ? 0 : 1;
+  // There is no optimized YV24 MMX routine so we check for this and
+  // fall back to the C code.
+  bool has_mmx = supports_mmx() && yuv_type != YV24;
+  bool odd_pic_x = yuv_type != YV24 && pic_x % 2 != 0;
   int x_width = odd_pic_x ? pic_width - 1 : pic_width;
 
   for (int y = pic_y; y < pic_height + pic_y; ++y) {
     uint8* rgb_row = rgb_buf + (y - pic_y) * rgb_pitch;
     const uint8* y_ptr = y_buf + y * y_pitch + pic_x;
-    const uint8* u_ptr = u_buf + (y >> y_shift) * uv_pitch + (pic_x >> 1);
-    const uint8* v_ptr = v_buf + (y >> y_shift) * uv_pitch + (pic_x >> 1);
+    const uint8* u_ptr = u_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
+    const uint8* v_ptr = v_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
 
     if (odd_pic_x) {
       // Handle the single odd pixel manually and use the
       // fast routines for the remaining.
       FastConvertYUVToRGB32Row_C(y_ptr++,
                                  u_ptr++,
                                  v_ptr++,
                                  rgb_row,
-                                 1);
+                                 1,
+                                 x_shift);
       rgb_row += 4;
     }
 
     if (has_mmx)
       FastConvertYUVToRGB32Row(y_ptr,
                                u_ptr,
                                v_ptr,
                                rgb_row,
                                x_width);
     else
       FastConvertYUVToRGB32Row_C(y_ptr,
                                  u_ptr,
                                  v_ptr,
                                  rgb_row,
-                                 x_width);
+                                 x_width,
+                                 x_shift);
   }
 
   // MMX used for FastConvertYUVToRGB32Row requires emms instruction.
   if (has_mmx)
     EMMS();
 }
 
 }  // namespace gfx

--- a/gfx/ycbcr/yuv_convert.h
+++ b/gfx/ycbcr/yuv_convert.h
@@ -9,18 +9,19 @@
 
 namespace mozilla {
 
 namespace gfx {
 
 // Type of YUV surface.
 // The value of these enums matter as they are used to shift vertical indices.
 enum YUVType {
-  YV16 = 0,           // YV16 is half width and full height chroma channels.
-  YV12 = 1            // YV12 is half width and half height chroma channels.
+  YV12 = 0,           // YV12 is half width and half height chroma channels.
+  YV16 = 1,           // YV16 is half width and full height chroma channels.
+  YV24 = 2            // YV24 is full width and full height chroma channels.
 };
 
 // Convert a frame of YUV to 32 bit ARGB.
 // Pass in YV16/YV12 depending on source format
 void ConvertYCbCrToRGB32(const uint8* yplane,
                          const uint8* uplane,
                          const uint8* vplane,
                          uint8* rgbframe,

--- a/gfx/ycbcr/yuv_row.h
+++ b/gfx/ycbcr/yuv_row.h
@@ -20,17 +20,18 @@ void FastConvertYUVToRGB32Row(const uint
                               const uint8* v_buf,
                               uint8* rgb_buf,
                               int width);
 
 void FastConvertYUVToRGB32Row_C(const uint8* y_buf,
                                 const uint8* u_buf,
                                 const uint8* v_buf,
                                 uint8* rgb_buf,
-                                int width);
+                                int width,
+                                unsigned int x_shift);
 
 
 }  // extern "C"
 
 // x64 uses MMX2 (SSE) so emms is not required.
 #if !defined(ARCH_CPU_X86_64) && !defined(ARCH_CPU_PPC)
 #if defined(_MSC_VER)
 #define EMMS() __asm emms

--- a/gfx/ycbcr/yuv_row_c.cpp
+++ b/gfx/ycbcr/yuv_row_c.cpp
@@ -153,24 +153,29 @@ static inline void YuvPixel(uint8 y,
                                         (clip(C298a + cr) << 16) |
                                         (0xff000000);
 }
 
 void FastConvertYUVToRGB32Row_C(const uint8* y_buf,
                               const uint8* u_buf,
                               const uint8* v_buf,
                               uint8* rgb_buf,
-                              int width) {
+                              int width,
+                              unsigned int x_shift) {
   for (int x = 0; x < width; x += 2) {
-    uint8 u = u_buf[x >> 1];
-    uint8 v = v_buf[x >> 1];
+    uint8 u = u_buf[x >> x_shift];
+    uint8 v = v_buf[x >> x_shift];
     uint8 y0 = y_buf[x];
     YuvPixel(y0, u, v, rgb_buf);
     if ((x + 1) < width) {
       uint8 y1 = y_buf[x + 1];
+      if (x_shift == 0) {
+        u = u_buf[x + 1];
+        v = v_buf[x + 1];
+      }
       YuvPixel(y1, u, v, rgb_buf + 4);
     }
     rgb_buf += 8;  // Advance 2 pixels.
   }
 }
 
 }  // extern "C"
 

new file mode 100644
--- /dev/null
+++ b/gfx/ycbcr/yv24.patch
@@ -0,0 +1,172 @@
+diff --git a/gfx/ycbcr/yuv_convert.cpp b/gfx/ycbcr/yuv_convert.cpp
+index b22e778..cdbb040 100644
+--- a/gfx/ycbcr/yuv_convert.cpp
++++ b/gfx/ycbcr/yuv_convert.cpp
+@@ -6,16 +6,17 @@
+ // http://www.fourcc.org/yuv.php
+ // The actual conversion is best described here
+ // http://en.wikipedia.org/wiki/YUV
+ // An article on optimizing YUV conversion using tables instead of multiplies
+ // http://lestourtereaux.free.fr/papers/data/yuvrgb.pdf
+ //
+ // YV12 is a full plane of Y and a half height, half width chroma planes
+ // YV16 is a full plane of Y and a full height, half width chroma planes
++// YV24 is a full plane of Y and a full height, full width chroma planes
+ //
+ // ARGB pixel format is output, which on little endian is stored as BGRA.
+ // The alpha is set to 255, allowing the application to use RGBA or RGB32.
+ 
+ #include "yuv_convert.h"
+ 
+ // Header for low level row functions.
+ #include "yuv_row.h"
+@@ -33,50 +34,55 @@ void ConvertYCbCrToRGB32(const uint8* y_buf,
+                          int pic_x,
+                          int pic_y,
+                          int pic_width,
+                          int pic_height,
+                          int y_pitch,
+                          int uv_pitch,
+                          int rgb_pitch,
+                          YUVType yuv_type) {
+-  unsigned int y_shift = yuv_type;
+-  bool has_mmx = supports_mmx();
+-  bool odd_pic_x = pic_x % 2 != 0;
++  unsigned int y_shift = yuv_type == YV12 ? 1 : 0;
++  unsigned int x_shift = yuv_type == YV24 ? 0 : 1;
++  // There is no optimized YV24 MMX routine so we check for this and
++  // fall back to the C code.
++  bool has_mmx = supports_mmx() && yuv_type != YV24;
++  bool odd_pic_x = yuv_type != YV24 && pic_x % 2 != 0;
+   int x_width = odd_pic_x ? pic_width - 1 : pic_width;
+ 
+   for (int y = pic_y; y < pic_height + pic_y; ++y) {
+     uint8* rgb_row = rgb_buf + (y - pic_y) * rgb_pitch;
+     const uint8* y_ptr = y_buf + y * y_pitch + pic_x;
+-    const uint8* u_ptr = u_buf + (y >> y_shift) * uv_pitch + (pic_x >> 1);
+-    const uint8* v_ptr = v_buf + (y >> y_shift) * uv_pitch + (pic_x >> 1);
++    const uint8* u_ptr = u_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
++    const uint8* v_ptr = v_buf + (y >> y_shift) * uv_pitch + (pic_x >> x_shift);
+ 
+     if (odd_pic_x) {
+       // Handle the single odd pixel manually and use the
+       // fast routines for the remaining.
+       FastConvertYUVToRGB32Row_C(y_ptr++,
+                                  u_ptr++,
+                                  v_ptr++,
+                                  rgb_row,
+-                                 1);
++                                 1,
++                                 x_shift);
+       rgb_row += 4;
+     }
+ 
+     if (has_mmx)
+       FastConvertYUVToRGB32Row(y_ptr,
+                                u_ptr,
+                                v_ptr,
+                                rgb_row,
+                                x_width);
+     else
+       FastConvertYUVToRGB32Row_C(y_ptr,
+                                  u_ptr,
+                                  v_ptr,
+                                  rgb_row,
+-                                 x_width);
++                                 x_width,
++                                 x_shift);
+   }
+ 
+   // MMX used for FastConvertYUVToRGB32Row requires emms instruction.
+   if (has_mmx)
+     EMMS();
+ }
+ 
+ }  // namespace gfx
+diff --git a/gfx/ycbcr/yuv_convert.h b/gfx/ycbcr/yuv_convert.h
+index 6735b77..15fe381 100644
+--- a/gfx/ycbcr/yuv_convert.h
++++ b/gfx/ycbcr/yuv_convert.h
+@@ -9,18 +9,19 @@
+ 
+ namespace mozilla {
+ 
+ namespace gfx {
+ 
+ // Type of YUV surface.
+ // The value of these enums matter as they are used to shift vertical indices.
+ enum YUVType {
+-  YV16 = 0,           // YV16 is half width and full height chroma channels.
+-  YV12 = 1            // YV12 is half width and half height chroma channels.
++  YV12 = 0,           // YV12 is half width and half height chroma channels.
++  YV16 = 1,           // YV16 is half width and full height chroma channels.
++  YV24 = 2            // YV24 is full width and full height chroma channels.
+ };
+ 
+ // Convert a frame of YUV to 32 bit ARGB.
+ // Pass in YV16/YV12 depending on source format
+ void ConvertYCbCrToRGB32(const uint8* yplane,
+                          const uint8* uplane,
+                          const uint8* vplane,
+                          uint8* rgbframe,
+diff --git a/gfx/ycbcr/yuv_row.h b/gfx/ycbcr/yuv_row.h
+index 2a82972..d776dac 100644
+--- a/gfx/ycbcr/yuv_row.h
++++ b/gfx/ycbcr/yuv_row.h
+@@ -20,17 +20,18 @@ void FastConvertYUVToRGB32Row(const uint8* y_buf,
+                               const uint8* v_buf,
+                               uint8* rgb_buf,
+                               int width);
+ 
+ void FastConvertYUVToRGB32Row_C(const uint8* y_buf,
+                                 const uint8* u_buf,
+                                 const uint8* v_buf,
+                                 uint8* rgb_buf,
+-                                int width);
++                                int width,
++                                unsigned int x_shift);
+ 
+ 
+ }  // extern "C"
+ 
+ // x64 uses MMX2 (SSE) so emms is not required.
+ #if !defined(ARCH_CPU_X86_64) && !defined(ARCH_CPU_PPC)
+ #if defined(_MSC_VER)
+ #define EMMS() __asm emms
+diff --git a/gfx/ycbcr/yuv_row_c.cpp b/gfx/ycbcr/yuv_row_c.cpp
+index d3bdab4..36d9bda 100644
+--- a/gfx/ycbcr/yuv_row_c.cpp
++++ b/gfx/ycbcr/yuv_row_c.cpp
+@@ -153,24 +153,29 @@ static inline void YuvPixel(uint8 y,
+                                         (clip(C298a + cr) << 16) |
+                                         (0xff000000);
+ }
+ 
+ void FastConvertYUVToRGB32Row_C(const uint8* y_buf,
+                               const uint8* u_buf,
+                               const uint8* v_buf,
+                               uint8* rgb_buf,
+-                              int width) {
++                              int width,
++                              unsigned int x_shift) {
+   for (int x = 0; x < width; x += 2) {
+-    uint8 u = u_buf[x >> 1];
+-    uint8 v = v_buf[x >> 1];
++    uint8 u = u_buf[x >> x_shift];
++    uint8 v = v_buf[x >> x_shift];
+     uint8 y0 = y_buf[x];
+     YuvPixel(y0, u, v, rgb_buf);
+     if ((x + 1) < width) {
+       uint8 y1 = y_buf[x + 1];
++      if (x_shift == 0) {
++        u = u_buf[x + 1];
++        v = v_buf[x + 1];
++      }
+       YuvPixel(y1, u, v, rgb_buf + 4);
+     }
+     rgb_buf += 8;  // Advance 2 pixels.
+   }
+ }
+ 
+ }  // extern "C"
+