avutil/frame: add new interlaced and top_field_first flags

Signed-off-by: James Almer <jamrial@gmail.com>

libavutil/frame.h

@@ -586,6 +586,15 @@ typedef struct AVFrame {
  * A flag to mark the frames which need to be decoded, but shouldn't be output.
  */
 #define AV_FRAME_FLAG_DISCARD   (1 << 2)
+/**
+ * A flag to mark frames whose content is interlaced.
+ */
+#define AV_FRAME_FLAG_INTERLACED (1 << 3)
+/**
+ * A flag to mark frames where the top field is displayed first if the content
+ * is interlaced.
+ */
+#define AV_FRAME_FLAG_TOP_FIELD_FIRST (1 << 4)
 /**
  * @}
  */