Improve performance by bypass libavfilter when we are not doing any filtering.

diff --git a/modules/ffmpeg/producer/filter/filter.cpp b/modules/ffmpeg/producer/filter/filter.cpp
index ab4e259e5520d1a1440f77295721fb16d3163035..537f2fb59b334cb7660230f549b853c267383a07 100644 (file)
--- a/modules/ffmpeg/producer/filter/filter.cpp
+++ b/modules/ffmpeg/producer/filter/filter.cpp
@@ -37,6 +37,7 @@
 #include <cstdio>
 #include <sstream>
 #include <string>
+#include <queue>
 
 #if defined(_MSC_VER)
 #pragma warning (push)
@@ -60,11 +61,13 @@ namespace caspar { namespace ffmpeg {
        
 struct filter::implementation
 {
-       std::string                                             filtergraph_;
+       std::string                                                             filtergraph_;
 
-       std::shared_ptr<AVFilterGraph>  video_graph_;   
-    AVFilterContext*                           video_graph_in_;  
-    AVFilterContext*                           video_graph_out_; 
+       std::shared_ptr<AVFilterGraph>                  video_graph_;
+    AVFilterContext*                                           video_graph_in_;
+    AVFilterContext*                                           video_graph_out_;
+
+       std::queue<std::shared_ptr<AVFrame>>    fast_path_;
                
        implementation(
                        int in_width,
@@ -221,15 +224,33 @@ struct filter::implementation
                }
        }
 
+       bool fast_path() const
+       {
+               return filtergraph_.empty();
+       }
+
        void push(const std::shared_ptr<AVFrame>& src_av_frame)
-       {               
-               FF(av_buffersrc_add_frame(
-                       video_graph_in_, 
-                       src_av_frame.get()));
+       {
+               if (fast_path())
+                       fast_path_.push(src_av_frame);
+               else
+                       FF(av_buffersrc_add_frame(
+                               video_graph_in_, 
+                               src_av_frame.get()));
        }
 
        std::shared_ptr<AVFrame> poll()
        {
+               if (fast_path())
+               {
+                       if (fast_path_.empty())
+                               return nullptr;
+
+                       auto result = fast_path_.front();
+                       fast_path_.pop();
+                       return result;
+               }
+
                std::shared_ptr<AVFrame> filt_frame(
                        av_frame_alloc(), 
                        [](AVFrame* p)