avcodec/mpeg12enc: Move high resolution thread check to before initializing threads

Cleaner solution is welcome!

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/pthread_slice.c

@@ -186,6 +186,12 @@ int ff_slice_thread_init(AVCodecContext *avctx)
     w32thread_init();
 #endif
 
+    // We cannot do this in the encoder init as the threads are created before
+    if (av_codec_is_encoder(avctx->codec) &&
+        avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO &&
+        avctx->height > 2800)
+        thread_count = avctx->thread_count = 1;
+
     if (!thread_count) {
         int nb_cpus = av_cpu_count();
         if  (avctx->height)