ffmpeg.c: check for interlaced flag in the correct place.

In the corresponding codec context, not global options storage.

ffmpeg.c

@@ -1186,7 +1186,7 @@ static void do_video_out(AVFormatContext *s,
             /* better than nothing: use input picture interlaced
                settings */
             big_picture.interlaced_frame = in_picture->interlaced_frame;
-            if(avcodec_opts[AVMEDIA_TYPE_VIDEO]->flags & (CODEC_FLAG_INTERLACED_DCT|CODEC_FLAG_INTERLACED_ME)){
+            if (ost->st->codec->flags & (CODEC_FLAG_INTERLACED_DCT|CODEC_FLAG_INTERLACED_ME)) {
                 if(top_field_first == -1)
                     big_picture.top_field_first = in_picture->top_field_first;
                 else