@@ -3356,6 +3356,7 @@ static int check_keyboard_interaction(int64_t cur_time)

 static void *input_thread(void *arg)

 {

     InputFile *f = arg;

+    unsigned flags = f->non_blocking ? AV_THREAD_MESSAGE_NONBLOCK : 0;

     int ret = 0;

     while (1) {

@@ -3371,7 +3372,15 @@ static void *input_thread(void *arg)

             break;

         }

         av_dup_packet(&pkt);

-        ret = av_thread_message_queue_send(f->in_thread_queue, &pkt, 0);

+        ret = av_thread_message_queue_send(f->in_thread_queue, &pkt, flags);

+        if (flags && ret == AVERROR(EAGAIN)) {

+            flags = 0;

+            ret = av_thread_message_queue_send(f->in_thread_queue, &pkt, flags);

+            av_log(f->ctx, AV_LOG_WARNING,

+                   "Thread message queue blocking; consider raising the "

+                   "thread_queue_size option (current value: %d)\n",

+                   f->thread_queue_size);

+        }

         if (ret < 0) {

             if (ret != AVERROR_EOF)

                 av_log(f->ctx, AV_LOG_ERROR,