diff --git a/libavcodec/snow.h b/libavcodec/snow.h
index 0f75419b36..b6a8bf4d7f 100644
--- a/libavcodec/snow.h
+++ b/libavcodec/snow.h
@@ -117,7 +117,7 @@ typedef struct SnowContext{
     H264QpelContext h264qpel;
     MpegvideoEncDSPContext mpvencdsp;
     SnowDWTContext dwt;
-    AVFrame *new_picture;
+    const AVFrame *new_picture;
     AVFrame *input_picture;              ///< new_picture with the internal linesizes
     AVFrame *current_picture;
     AVFrame *last_picture[MAX_REF_FRAMES];