dec/VC1: Update the comment for b_picture_fraction

b_picture_fraction is used as an index in practice, so I updated the
comments to reduce the confusion to user

Signed-off-by: Xiang, Haihao <haihao.xiang@intel.com>

diff --git a/va/va.h b/va/va.h
index c5542a7..ed451b5 100644 (file)
--- a/va/va.h
+++ b/va/va.h
@@ -1877,7 +1877,7 @@ typedef struct _VAPictureParameterBufferVC1
         unsigned int value;
     } range_mapping_fields;
 
-    unsigned char b_picture_fraction;  /* PICTURE_LAYER::BFRACTION */
+    unsigned char b_picture_fraction;  /* Index for PICTURE_LAYER::BFRACTION value in Table 40 (7.1.1.14) */
     unsigned char cbp_table;           /* PICTURE_LAYER::CBPTAB/ICBPTAB */
     unsigned char mb_mode_table;       /* PICTURE_LAYER::MBMODETAB */
     unsigned char range_reduction_frame;/* PICTURE_LAYER::RANGEREDFRM */