diff --git a/src/beauty/beauty-demo.cpp b/src/beauty/beauty-demo.cpp
index 82a4fe49b..ec665abe1 100644
--- a/src/beauty/beauty-demo.cpp
+++ b/src/beauty/beauty-demo.cpp
@@ -15,7 +15,9 @@ constexpr unsigned long HEIGHT = 1080;
 constexpr double SCALE = 0.125;
 constexpr bool OFFSCREEN = false;
 constexpr int VA_HW_DEVICE_INDEX = 0;
-constexpr int BLUR_KERNEL_SIZE = WIDTH / 360 % 2 == 0 ? WIDTH / 360 + 1 : WIDTH / 360;
+constexpr unsigned long DIAG = hypot(double(WIDTH), double(HEIGHT));
+
+constexpr int BLUR_KERNEL_SIZE = DIAG / 413 % 2 == 0 ? DIAG / 413 + 1 : DIAG / 413;
 
 using std::cerr;
 using std::endl;
diff --git a/src/tetra/tetra-demo.cpp b/src/tetra/tetra-demo.cpp
index f21dbe143..b3c30568e 100644
--- a/src/tetra/tetra-demo.cpp
+++ b/src/tetra/tetra-demo.cpp
@@ -8,8 +8,9 @@ constexpr double FPS = 60;
 constexpr bool OFFSCREEN = false;
 constexpr const char* OUTPUT_FILENAME = "tetra-demo.mkv";
 constexpr const int VA_HW_DEVICE_INDEX = 0;
+constexpr unsigned long DIAG = hypot(double(WIDTH), double(HEIGHT));
 
-constexpr int GLOW_KERNEL_SIZE = WIDTH / 120 % 2 == 0 ? WIDTH / 120  + 1 : WIDTH / 120;
+constexpr int GLOW_KERNEL_SIZE = DIAG / 138 % 2 == 0 ? DIAG / 138 + 1 : DIAG / 138;
 
 using std::cerr;
 using std::endl;
diff --git a/src/video/video-demo.cpp b/src/video/video-demo.cpp
index e08fdee5e..ecfa4631a 100644
--- a/src/video/video-demo.cpp
+++ b/src/video/video-demo.cpp
@@ -8,8 +8,10 @@ constexpr long unsigned int HEIGHT = 1080;
 constexpr const int VA_HW_DEVICE_INDEX = 0;
 constexpr bool OFFSCREEN = false;
 constexpr const char *OUTPUT_FILENAME = "video-demo.mkv";
+constexpr unsigned long DIAG = hypot(double(WIDTH), double(HEIGHT));
+
+constexpr int GLOW_KERNEL_SIZE = DIAG / 138 % 2 == 0 ? DIAG / 138 + 1 : DIAG / 138;
 
-constexpr int GLOW_KERNEL_SIZE = WIDTH / 120 % 2 == 0 ? WIDTH / 120  + 1 : WIDTH / 120;
 
 using std::cerr;
 using std::endl;