From 1f8cb47a111340cf47e9e456975c248d757afac2 Mon Sep 17 00:00:00 2001
From: Roz K <roz@rozk.net>
Date: Sat, 7 Jun 2025 19:02:17 +0200
Subject: [PATCH] un-fisheye filter for gopro 8:7 ratio, wide fov, without
 hypersmooth

---
 README.md                                  |  7 +++--
 unfish_gopro_8-7_wide_hypersmooth-off.glsl | 33 ++++++++++++++++++++++
 2 files changed, 38 insertions(+), 2 deletions(-)
 create mode 100644 unfish_gopro_8-7_wide_hypersmooth-off.glsl

diff --git a/README.md b/README.md
index 3c74400..fcd709c 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
-# avidemux_shaders
+# Avidemux Shaders
 
-Shaders for avidemux
\ No newline at end of file
+Shaders for Avidemux with OpenGL support
+
+```unfish_gopro_8-7_wide_hypersmooth-off.glsl```
+Fisheye removal for GoPro, 8:7 aspect ratio, wide FOV, HyperSmooth off
diff --git a/unfish_gopro_8-7_wide_hypersmooth-off.glsl b/unfish_gopro_8-7_wide_hypersmooth-off.glsl
new file mode 100644
index 0000000..a89ddb0
--- /dev/null
+++ b/unfish_gopro_8-7_wide_hypersmooth-off.glsl
@@ -0,0 +1,33 @@
+// Adapted from https://github.com/duducosmos/defisheye
+// (then resize to 1568x1080)
+
+#extension GL_ARB_texture_rectangle: enable
+
+uniform sampler2DRect myTextureY;
+uniform sampler2DRect myTextureU;
+uniform sampler2DRect myTextureV;
+uniform vec2 myResolution;
+uniform float pts;
+
+const vec2 half_pixel = vec2(0.5, 0.5);
+const float pi = 3.1415927;
+
+const float input_fov = 150.0 * pi / 720.0;
+const float output_fov = 116.0 * pi / 360.0;
+
+vec2 unfish(vec2 coord) {
+    vec2 center = myResolution * 0.5;
+    vec2 pos = coord - center;
+    float rd = length(pos);
+    float diameter = sqrt(dot(myResolution, myResolution));
+    return center + pos * ((diameter / (2.0 * sin(input_fov))) * sin(atan(rd / (diameter / (2.0 * tan(output_fov)))) * 0.5) / rd);
+}
+
+void main() {
+    vec2 y_coord = unfish(gl_TexCoord[0].xy + half_pixel);
+    vec2 uv_coord = y_coord * 0.5;
+    vec4 y = texture2DRect(myTextureY, y_coord);
+    vec4 u = texture2DRect(myTextureU, uv_coord);
+    vec4 v = texture2DRect(myTextureV, uv_coord);
+    gl_FragColor = vec4(y.r, u.r, v.r, 1.0);
+}