diff --git a/libavcodec/dnxhdenc.c b/libavcodec/dnxhdenc.c
index f206b72d60..54ccec4296 100644
--- a/libavcodec/dnxhdenc.c
+++ b/libavcodec/dnxhdenc.c
@@ -711,7 +711,7 @@ static void dnxhd_load_picture(DNXHDEncContext *ctx, const AVFrame *frame)
     ctx->cur_field = frame->interlaced_frame && !frame->top_field_first;
 }
 
-static int dnxhd_encode_picture(AVCodecContext *avctx, unsigned char *buf, int buf_size, const void *data)
+static int dnxhd_encode_picture(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data)
 {
     DNXHDEncContext *ctx = avctx->priv_data;
     int first_field = 1;