diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index 440e398a2c28a3e96b508aed02fefb6d4c1a7baa..dde5928920d52acc017f8722d7385f4ec6804c9f 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -2428,6 +2428,7 @@ static inline void copy_context_after_encode(MpegEncContext *d, MpegEncContext *
     d->block= s->block;
     for(i=0; i<6; i++)
         d->block_last_index[i]= s->block_last_index[i];
+    d->interlaced_dct= s->interlaced_dct;
 }
 
 static inline void encode_mb_hq(MpegEncContext *s, MpegEncContext *backup, MpegEncContext *best, int type,