diff --git a/lib/image_inference_impl.h b/lib/image_inference_impl.h
index 055060c..11937d1 100644
--- a/lib/image_inference_impl.h
+++ b/lib/image_inference_impl.h
@@ -252,7 +252,7 @@ class image_inference_impl : public image_inference, base_impl {
   boost::scoped_ptr<std::thread> inference_thread_;
   boost::scoped_ptr<torchserve_client> torchserve_client_;
   boost::lockfree::spsc_queue<output_item_type> inference_q_{MAX_INFERENCE};
-  boost::lockfree::spsc_queue<std::string> json_q_{MAX_INFERENCE};
+  boost::lockfree::spsc_queue<std::string> json_q_{MAX_INFERENCE * 2};
   boost::scoped_ptr<cv::Mat> cmapped_buffer_, resized_buffer_,
       normalized_buffer_;
 
diff --git a/lib/iq_inference_impl.cc b/lib/iq_inference_impl.cc
index 62cb072..50b7a74 100644
--- a/lib/iq_inference_impl.cc
+++ b/lib/iq_inference_impl.cc
@@ -417,6 +417,7 @@ void iq_inference_impl::process_items_(COUNT_T power_in_count,
     if (background_) {
       if (!inference_q_.push(output_item)) {
         delete_output_item_(output_item);
+        --serial_;
         if (host_now_() - last_full_time_ > 5) {
           d_logger->error(
               "inference queue full (increase inference dB threshold "
diff --git a/lib/iq_inference_impl.h b/lib/iq_inference_impl.h
index 56d76ce..c18c00c 100644
--- a/lib/iq_inference_impl.h
+++ b/lib/iq_inference_impl.h
@@ -253,7 +253,7 @@ class iq_inference_impl : public iq_inference, base_impl {
                          boost::lockfree::capacity<MAX_INFERENCE>>
       inference_q_;
   boost::lockfree::queue<std::string *,
-                         boost::lockfree::capacity<MAX_INFERENCE>>
+                         boost::lockfree::capacity<MAX_INFERENCE * 2>>
       json_q_;
   boost::shared_ptr<boost::asio::io_service> io_service_;
   boost::shared_ptr<boost::asio::io_service::work> work_;