add "is_first_field" into VAPictureParameterBufferMPEG2

diff --git a/src/va.h b/src/va.h
index 0d61518..8125a26 100755 (executable)
--- a/src/va.h
+++ b/src/va.h
@@ -427,6 +427,7 @@ typedef struct _VAPictureParameterBufferMPEG2
             unsigned char alternate_scan               : 1;
             unsigned char repeat_first_field           : 1;
             unsigned char progressive_frame            : 1;
+            unsigned char is_first_field               : 1;/* indicate whether the current field is the first field for field picture */
         };
         unsigned int picture_coding_extension;
     };