threads: introduce CODEC_CAP_AUTO_THREADS and add it to libx264

Some external codecs have their own code to determine the best number
of threads. This number is not necessary the number of cpu cores.
Thread_count will be only 0 if the codec has CODEC_CAP_AUTO_THREADS.

1 files changed, 3 insertions, 0 deletions

diff --git a/libavcodec/pthread.c b/libavcodec/pthread.c
index 400abf4f6c..54a0eb3ab7 100644
--- a/libavcodec/pthread.c
+++ b/libavcodec/pthread.c
@@ -982,6 +982,9 @@ static void validate_thread_parameters(AVCodecContext *avctx)
     } else if (avctx->codec->capabilities & CODEC_CAP_SLICE_THREADS &&
                avctx->thread_type & FF_THREAD_SLICE) {
         avctx->active_thread_type = FF_THREAD_SLICE;
+    } else if (!(avctx->codec->capabilities & CODEC_CAP_AUTO_THREADS)) {
+        avctx->thread_count       = 1;
+        avctx->active_thread_type = 0;
     }
 }