Slow OpenFX temporal frames

I've noticed that OpenFX plugins in Resolve that access many frames are extremely slow (perhaps around 3x slower than other hosts like Premiere and Final Cut, in our experience). This seems to date back a while judging by a couple posts in the forums, especially with temporal Sapphire plugins. I can demonstrate this easily with the example plugins, if you modify TemporalBlurPlugin to require more than just 3 frames, and this can drop playback down to around 1 FPS at times.

Hopefully this can be improved in Resolve 18

Code: Select all

diff -ur /Library/Application Support/Blackmagic Design/DaVinci Resolve/Developer/OpenFX/TemporalBlurPlugin/TemporalBlurPlugin.cpp ./TemporalBlurPlugin/TemporalBlurPlugin.cpp
--- /Library/Application Support/Blackmagic Design/DaVinci Resolve/Developer/OpenFX/TemporalBlurPlugin/TemporalBlurPlugin.cpp   2021-03-30 08:54:11.000000000 -0700
+++ ./TemporalBlurPlugin/TemporalBlurPlugin.cpp   2021-04-24 15:03:24.000000000 -0700
@@ -211,6 +211,10 @@
     const int interval = m_IntervalParam->getValueAtTime(currFrameNum);
 
     // Get the src images
+    for (int i = currFrameNum - interval; i <= currFrameNum + interval; i++)
+    {
+        std::auto_ptr<OFX::Image> prevSrc(m_SrcClip->fetchImage(i));
+    }
     std::auto_ptr<OFX::Image> prevSrc(m_SrcClip->fetchImage(currFrameNum - interval));
     std::auto_ptr<OFX::Image> src(m_SrcClip->fetchImage(currFrameNum));
     std::auto_ptr<OFX::Image> nextSrc(m_SrcClip->fetchImage(currFrameNum + interval));
@@ -315,8 +319,8 @@
     param->setScriptName(p_Name);
     param->setHint(p_Hint);
     param->setDefault(2);
-    param->setRange(0, 5);
-    param->setDisplayRange(0, 5);
+    param->setRange(0, 10);
+    param->setDisplayRange(0, 10);
 
     if (p_Parent)
     {