diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 524bbb3de75c57971f597e9149a119b33f953fcb..de37dc423c5f8903d7fea474b1d2127b19f680f3 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -321,8 +321,8 @@ typedef struct MpegEncContext {
 
     int qscale;                 ///< QP
     int chroma_qscale;          ///< chroma QP
-    int lambda;                 ///< lagrange multipler used in rate distortion
-    int lambda2;                ///< (lambda*lambda) >> FF_LAMBDA_SHIFT
+    unsigned int lambda;        ///< lagrange multipler used in rate distortion
+    unsigned int lambda2;       ///< (lambda*lambda) >> FF_LAMBDA_SHIFT
     int *lambda_table;
     int adaptive_quant;         ///< use adaptive quantization
     int dquant;                 ///< qscale difference to prev qscale