Bug 551277 - Implement software YCbCr conversion in layers, replacing liboggplay color conversion code - r=roc

gfx/layers/ImageLayers.h

@@ -206,7 +206,22 @@ protected:
 /**
  * We assume that the image data is in the REC 470M color space (see
  * Theora specification, section 4.3.1).
- * XXX Eventually we should some color space parameter(s) here.
+ *
+ * The YCbCr format can be:
+ *
+ * 4:4:4 - CbCr width/height are the same as Y.
+ * 4:2:2 - CbCr width is half that of Y. Height is the same.
+ * 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:
@@ -220,16 +235,12 @@ public:
     PRUint8* mCrChannel;
     PRInt32 mCbCrStride;
     gfxIntSize mCbCrSize;
+    // Picture region
+    PRUint32 mPicX;
+    PRUint32 mPicY;
+    gfxIntSize mPicSize;
   };
 
-  typedef void (* ToARGBHook)(const Data& aData, PRUint8* aOutput);
-  /**
-   * XXX this is just a hack until we can get YCbCr conversion code into
-   * gfx
-   * This must be called before SetData().
-   */
-  virtual void SetRGBConverter(ToARGBHook aHook) {}
-
   /**
    * This makes a copy of the data buffers.
    * XXX Eventually we will change this to not make a copy of the data,