diff --git a/libavcodec/xvmc.h b/libavcodec/xvmc.h
index cb1b6f10d7..975b93a3eb 100644
--- a/libavcodec/xvmc.h
+++ b/libavcodec/xvmc.h
@@ -42,7 +42,7 @@ struct xvmc_render_state {
     int total_number_of_data_blocks;
     int mc_type; //XVMC_MPEG1/2/4,XVMC_H263 without XVMC_IDCT
     int idct;    //< indicate that IDCT acceleration level is used
-    int chroma_format; //420, 422, 444
+    int chroma_format;  ///< XVMC_CHROMA_FORMAT_420/422/444
     int unsigned_intra; //+-128 for intra pictures after clipping
     XvMCSurface* p_surface; //pointer to rendered surface, never changed