mpeg1enc: Disable threads for resolutions too large for multi-threading

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpeg12enc.c

@@ -145,6 +145,9 @@ static av_cold int encode_init(AVCodecContext *avctx)
 {
     MpegEncContext *s = avctx->priv_data;
 
+    if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && avctx->height > 2800)
+        avctx->thread_count = 1;
+
     if(ff_MPV_encode_init(avctx) < 0)
         return -1;