diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index f6011c76f9..befbb0a25a 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -686,7 +686,7 @@ static int decode_block(MJpegDecodeContext *s, int16_t *block, int component,
         av_log(s->avctx, AV_LOG_ERROR, "error dc\n");
         return AVERROR_INVALIDDATA;
     }
-    val = val * quant_matrix[0] + s->last_dc[component];
+    val = val * (unsigned)quant_matrix[0] + s->last_dc[component];
     val = av_clip_int16(val);
     s->last_dc[component] = val;
     block[0] = val;