Merge: if an output channel is checked, do not be identity if the B c…

…hannel is unchecked

Merge/Merge.cpp

@@ -1295,15 +1295,28 @@ MergePlugin::isIdentity(const IsIdentityArguments &args,
     }
 
     bool outputChannels[4];
+    bool srcBChannels[4];
     for (int c = 0; c < 4; ++c) {
         _outputChannels[c]->getValueAtTime(time, outputChannels[c]);
+        _bChannels[c]->getValueAtTime(time, srcBChannels[c]);
     }
     if (!outputChannels[0] && !outputChannels[1] && !outputChannels[2] && !outputChannels[3] && plane == kFnOfxImagePlaneColour) {
         identityClip = _srcClipB;
 
         return true;
     }
 
+    // For each checked output channels, if srcB channel is unchecked, we are not identity
+    for (int i = 0; i < 4; ++i) {
+        if (!outputChannels[i]) {
+            continue;
+        }
+        if (!srcBChannels[i]) {
+            return false;
+        }
+    }
+
+
     OfxRectI maskRoD;
     bool maskRoDValid = false;
     bool doMasking = ( ( !_maskApply || _maskApply->getValueAtTime(time) ) && _maskClip && _maskClip->isConnected() );
@@ -1329,6 +1342,10 @@ MergePlugin::isIdentity(const IsIdentityArguments &args,
         return false;
     }
 
+    if (Coords::rectIsInfinite(args.renderWindow)) {
+        return false;
+    }
+
     // The region of effect is only the set of the intersections between the A inputs and the mask.
     // If at least one of these regions intersects the renderwindow, the effect is not identity.