Give nice error message to fix codecs that call it this way.
Originally committed as revision 17452 to svn://svn.ffmpeg.org/ffmpeg/trunk
s->mb_height = (s->height + 15) / 16;
+ if(s->avctx->pix_fmt == PIX_FMT_NONE){
+ av_log(s->avctx, AV_LOG_ERROR, "decoding to PIX_FMT_NONE is not supported.\n");
+ return -1;
+ }
+
if(s->avctx->thread_count > MAX_THREADS || (s->avctx->thread_count > s->mb_height && s->mb_height)){
av_log(s->avctx, AV_LOG_ERROR, "too many threads\n");
return -1;