diff --git a/libavcodec/mjpeg.c b/libavcodec/mjpeg.c
index 2a10934978ac7a84c494692dcb8fcb66bc77bd48..2487f613757981795a06cc7444e7b0b206a714a1 100644
--- a/libavcodec/mjpeg.c
+++ b/libavcodec/mjpeg.c
@@ -1144,7 +1144,6 @@ static int mjpeg_decode_sof(MJpegDecodeContext *s)
 
         s->width = width;
         s->height = height;
-        avcodec_set_dimensions(s->avctx, width, height);
 
         /* test interlaced mode */
         if (s->first_picture &&
@@ -1153,9 +1152,11 @@ static int mjpeg_decode_sof(MJpegDecodeContext *s)
             s->interlaced = 1;
 //            s->bottom_field = (s->interlace_polarity) ? 1 : 0;
             s->bottom_field = 0;
-            s->avctx->height *= 2;
+            height *= 2;
         }
 
+        avcodec_set_dimensions(s->avctx, width, height);
+
         s->qscale_table= av_mallocz((s->width+15)/16);
 
         s->first_picture = 0;