diff --git a/host/platform/Windows/capture/D12/backend.h b/host/platform/Windows/capture/D12/backend.h
index 7e7b7c80..e9dc4b80 100644
--- a/host/platform/Windows/capture/D12/backend.h
+++ b/host/platform/Windows/capture/D12/backend.h
@@ -58,10 +58,11 @@ struct D12Backend
   CaptureResult (*sync)(D12Backend * instance,
     ID3D12CommandQueue * commandQueue);
 
-  ID3D12Resource * (*fetch)(D12Backend * instance,
-    unsigned frameBufferIndex,
-    const RECT ** dirtyRects,
-    unsigned * nbDirtyRects);
+  ID3D12Resource * (*fetch)(
+    D12Backend * instance,
+    unsigned     frameBufferIndex,
+    RECT      ** dirtyRects,
+    unsigned   * nbDirtyRects);
 };
 
 static inline bool d12_backendCreate(const D12Backend * backend,
@@ -96,8 +97,7 @@ static inline CaptureResult d12_backendSync(D12Backend * instance,
   { return instance->sync(instance, commandQueue); }
 
 static inline ID3D12Resource * d12_backendFetch(D12Backend * instance,
-  unsigned frameBufferIndex, const RECT ** dirtyRects,
-  unsigned * nbDirtyRects)
+  unsigned frameBufferIndex, RECT ** dirtyRects, unsigned * nbDirtyRects)
   { return instance->fetch(instance, frameBufferIndex, dirtyRects,
       nbDirtyRects); }
 
diff --git a/host/platform/Windows/capture/D12/backend/dd.c b/host/platform/Windows/capture/D12/backend/dd.c
index a07f107d..e874f351 100644
--- a/host/platform/Windows/capture/D12/backend/dd.c
+++ b/host/platform/Windows/capture/D12/backend/dd.c
@@ -419,7 +419,7 @@ static CaptureResult d12_dd_sync(D12Backend * instance,
 }
 
 static ID3D12Resource * d12_dd_fetch(D12Backend * instance,
-  unsigned frameBufferIndex, const RECT * dirtyRects[static D12_MAX_DIRTY_RECTS],
+  unsigned frameBufferIndex, RECT * dirtyRects[static D12_MAX_DIRTY_RECTS],
   unsigned * nbDirtyRects)
 {
   DDInstance * this = UPCAST(DDInstance, instance);
diff --git a/host/platform/Windows/capture/D12/d12.c b/host/platform/Windows/capture/D12/d12.c
index ac1c438b..ee959f8f 100644
--- a/host/platform/Windows/capture/D12/d12.c
+++ b/host/platform/Windows/capture/D12/d12.c
@@ -428,7 +428,7 @@ static CaptureResult d12_waitFrame(unsigned frameBufferIndex,
   CaptureResult result = CAPTURE_RESULT_ERROR;
   comRef_scopePush(1);
 
-  const RECT * dirtyRects;
+  RECT * dirtyRects;
   unsigned nbDirtyRects;
 
   comRef_defineLocal(ID3D12Resource, src);
@@ -543,7 +543,7 @@ static CaptureResult d12_getFrame(unsigned frameBufferIndex,
   CaptureResult result = CAPTURE_RESULT_ERROR;
   comRef_scopePush(3);
 
-  const RECT * dirtyRects;
+  RECT * dirtyRects;
   unsigned nbDirtyRects;
 
   comRef_defineLocal(ID3D12Resource, src);
@@ -572,7 +572,8 @@ static CaptureResult d12_getFrame(unsigned frameBufferIndex,
   if (this->allowRGB24)
   {
     next = d12_effectRun(
-      this->effectRGB24, *this->device, *this->computeCommand.gfxList, next);
+      this->effectRGB24, *this->device, *this->computeCommand.gfxList, next,
+      dirtyRects, &nbDirtyRects);
   }
 
   // copy into the framebuffer resource
diff --git a/host/platform/Windows/capture/D12/effect.h b/host/platform/Windows/capture/D12/effect.h
index f9357ffd..64ae4898 100644
--- a/host/platform/Windows/capture/D12/effect.h
+++ b/host/platform/Windows/capture/D12/effect.h
@@ -41,8 +41,11 @@ struct D12Effect
           D3D12_RESOURCE_DESC * dst);
 
   ID3D12Resource * (*run)(D12Effect * effect,
-    ID3D12Device3 * device, ID3D12GraphicsCommandList * commandList,
-    ID3D12Resource * src);
+    ID3D12Device3             * device,
+    ID3D12GraphicsCommandList * commandList,
+    ID3D12Resource            * src,
+    RECT                        dirtyRects[],
+    unsigned                  * nbDirtyRects);
 };
 
 static inline bool d12_effectCreate(const D12Effect * effect,
@@ -68,9 +71,13 @@ static inline bool d12_effectSetFormat(D12Effect * effect,
   { return effect->setFormat(effect, device, src, dst); }
 
 static inline ID3D12Resource * d12_effectRun(D12Effect * effect,
-  ID3D12Device3 * device, ID3D12GraphicsCommandList  * commandList,
-  ID3D12Resource * src)
-  { return effect->run(effect, device, commandList, src); }
+  ID3D12Device3              * device,
+  ID3D12GraphicsCommandList  * commandList,
+  ID3D12Resource             * src,
+  RECT                         dirtyRects[],
+  unsigned                   * nbDirtyRects)
+  { return effect->run(effect, device, commandList, src,
+    dirtyRects, nbDirtyRects); }
 
 // effect defines
 
diff --git a/host/platform/Windows/capture/D12/effect/rgb24.c b/host/platform/Windows/capture/D12/effect/rgb24.c
index d325b20a..7f32ca25 100644
--- a/host/platform/Windows/capture/D12/effect/rgb24.c
+++ b/host/platform/Windows/capture/D12/effect/rgb24.c
@@ -278,7 +278,7 @@ exit:
 
 static ID3D12Resource * d12_effect_rgb24Run(D12Effect * effect,
   ID3D12Device3 * device, ID3D12GraphicsCommandList * commandList,
-  ID3D12Resource * src)
+  ID3D12Resource * src, RECT dirtyRects[], unsigned * nbDirtyRects)
 {
   TestInstance * this = UPCAST(TestInstance, effect);
 
@@ -365,6 +365,14 @@ static ID3D12Resource * d12_effect_rgb24Run(D12Effect * effect,
     ID3D12GraphicsCommandList_ResourceBarrier(commandList, 1, &barrier);
   }
 
+  // adjust the dirty rects
+  for(RECT * rect = dirtyRects; rect < dirtyRects + *nbDirtyRects; ++rect)
+  {
+    unsigned width = rect->right - rect->left;
+    rect->left  = (rect->left * 3) / 4;
+    rect->right = rect->left + (width * 3 + 3) / 4;
+  }
+
   // return the output buffer
   return *this->dst;
 }