Merge "Set the maximum decode threads to be 8."

vp9/common/vp9_thread.h

@@ -22,6 +22,10 @@
 extern "C" {
 #endif
 
+// Set maximum decode threads to be 8 due to the limit of frame buffers
+// and not enough semaphores in the emulation layer on windows.
+#define MAX_DECODE_THREADS 8
+
 #if CONFIG_MULTITHREAD
 
 #if defined(_WIN32)
@@ -103,8 +107,8 @@ static INLINE int pthread_cond_destroy(pthread_cond_t *const condition) {
 static INLINE int pthread_cond_init(pthread_cond_t *const condition,
                                     void* cond_attr) {
   (void)cond_attr;
-  condition->waiting_sem_ = CreateSemaphore(NULL, 0, 1, NULL);
-  condition->received_sem_ = CreateSemaphore(NULL, 0, 1, NULL);
+  condition->waiting_sem_ = CreateSemaphore(NULL, 0, MAX_DECODE_THREADS, NULL);
+  condition->received_sem_ = CreateSemaphore(NULL, 0, MAX_DECODE_THREADS, NULL);
   condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL);
   if (condition->waiting_sem_ == NULL ||
       condition->received_sem_ == NULL ||

vp9/vp9_dx_iface.c

@@ -363,6 +363,8 @@ static vpx_codec_err_t init_decoder(vpx_codec_alg_priv_t *ctx) {
   ctx->num_cache_frames = 0;
   ctx->num_frame_workers =
       (ctx->frame_parallel_decode == 1) ? ctx->cfg.threads: 1;
+  if (ctx->num_frame_workers > MAX_DECODE_THREADS)
+    ctx->num_frame_workers = MAX_DECODE_THREADS;
   ctx->available_threads = ctx->num_frame_workers;
   ctx->flushed = 0;