fix pixel scale

README.md

@@ -2,10 +2,12 @@
 
 Shaders for Avidemux with OpenGL support
 
-## gopro_8:7 - Fisheye removal for GoPro 11+, 8:7 ratio, 60fps, HyperSmooth off
+## GoPro fisheye removal
 
 ![Sample image](https://blog.rozk.net/wp-content/uploads/2025/07/compare.png)
 
+### gopro_8:7 - Fisheye removal for GoPro 11+, 8:7 ratio, 60fps, HyperSmooth off
+
 - unfish_gopro_8:7.glsl  
 Shader for fisheye removal
 
@@ -21,15 +23,12 @@ Preset for mp4, FullHD, constant bitrate
 - preset_gopro_8:7_HD_720p.py  
 Preset for mp4, HD, constant bitrate
 
-- preset_gopro_8:7_QHD_540p.py  
-Preset for mp4, QHD, constant bitrate
-
 - compute_gopro_8:7.py  
 Script to compute output FOV and frame widening
 
 ### Installation for BSD/GNU-Linux systems:
 
-- Copy the presets to ~/.avidemux6/custom/
+- Copy the presets to ~/.avidemux6/custom/ or ~/.local/share/avidemux6/custom/
 - Copy the shader to /opt/rk/avidemux/ (or edit the preset to set the path)  
 
 Or just run the script install_gopro_8:7.sh
@@ -39,6 +38,6 @@ _For commercial OS's, figure out the paths yourself, then edit the presets to fi
 ### Usage:
 
 - Load and edit video(s)
-- Select "Custom/preset_gopro_8:7_..." in the menu
+- Select "Custom/preset_gopro..." in the menu
 - Add filters
 - Save the video

gopro_8:7/compute_gopro_8:7.py

@@ -31,7 +31,6 @@ def width_rounded_8(height):
     width = int(round(height * input_ratio))
     return ((width + 4) // 8) * 8
 
-print("QHD            = %i x 540" % width_rounded_8(540))
 print("HD             = %i x 720" % width_rounded_8(720))
 print("Full HD        = %i x 1080" % width_rounded_8(1080))
 print("4K             = %i x 2160" % width_rounded_8(2160))

gopro_8:7/preset_gopro_8:7_4K_2160p.py

@@ -93,18 +93,11 @@ adm.addVideoFilter(
     "swscale",
     "width=2472",
     "height=2160",
-    "algo=1",
+    "algo=2",
     "sourceAR=0",
     "targetAR=0",
     "lockAR=False",
     "roundup=2")
-adm.addVideoFilter(
-    "MplayerDenoise3DHQ",
-    "mode=4",
-    "luma_spatial=4.000000",
-    "chroma_spatial=3.000000",
-    "luma_temporal=6.000000",
-    "chroma_temporal=4.500000")
 adm.setContainer(
     "MP4",
     "muxerType=0",

gopro_8:7/preset_gopro_8:7_4K_youtube.py

@@ -93,18 +93,11 @@ adm.addVideoFilter(
     "swscale",
     "width=2472",
     "height=2160",
-    "algo=1",
+    "algo=2",
     "sourceAR=0",
     "targetAR=0",
     "lockAR=False",
     "roundup=2")
-adm.addVideoFilter(
-    "MplayerDenoise3DHQ",
-    "mode=4",
-    "luma_spatial=4.000000",
-    "chroma_spatial=3.000000",
-    "luma_temporal=6.000000",
-    "chroma_temporal=4.500000")
 adm.setContainer(
     "MP4",
     "muxerType=0",

gopro_8:7/preset_gopro_8:7_FullHD_1080p.py

@@ -93,18 +93,11 @@ adm.addVideoFilter(
     "swscale",
     "width=1232",
     "height=1080",
-    "algo=1",
+    "algo=2",
     "sourceAR=0",
     "targetAR=0",
     "lockAR=False",
     "roundup=2")
-adm.addVideoFilter(
-    "MplayerDenoise3DHQ",
-    "mode=4",
-    "luma_spatial=4.000000",
-    "chroma_spatial=3.000000",
-    "luma_temporal=6.000000",
-    "chroma_temporal=4.500000")
 adm.setContainer(
     "MP4",
     "muxerType=0",

gopro_8:7/preset_gopro_8:7_HD_720p.py

@@ -93,18 +93,11 @@ adm.addVideoFilter(
     "swscale",
     "width=824",
     "height=720",
-    "algo=1",
+    "algo=2",
     "sourceAR=0",
     "targetAR=0",
     "lockAR=False",
     "roundup=2")
-adm.addVideoFilter(
-    "MplayerDenoise3DHQ",
-    "mode=4",
-    "luma_spatial=4.000000",
-    "chroma_spatial=3.000000",
-    "luma_temporal=6.000000",
-    "chroma_temporal=4.500000")
 adm.setContainer(
     "MP4",
     "muxerType=0",

gopro_8:7/preset_gopro_8:7_QHD_540p.py

@@ -1,116 +0,0 @@
-#PY  <- Needed to identify #
-# RozK
-# Custom preset for GoPro, 8:7 ratio, without hypersmooth, output widened scaled to QHD (540p)
-
-adm = Avidemux()
-adm.videoCodec(
-    "x264",
-    "useAdvancedConfiguration=False",
-    "general.params=CBR=8192",
-    "general.threads=0",
-    "general.preset=slow",
-    "general.tuning=film",
-    "general.profile=high",
-    "general.fast_decode=False",
-    "general.zero_latency=False",
-    "general.fast_first_pass=True",
-    "general.blueray_compatibility=False",
-    "general.fake_interlaced=False",
-    "level=-1",
-    "vui.sar_height=1",
-    "vui.sar_width=1",
-    "vui.overscan=0",
-    "vui.vidformat=5",
-    "vui.fullrange=False",
-    "vui.colorprim=2",
-    "vui.transfer=2",
-    "vui.colmatrix=2",
-    "vui.chroma_loc=0",
-    "MaxRefFrames=3",
-    "MinIdr=25",
-    "MaxIdr=250",
-    "i_scenecut_threshold=40",
-    "intra_refresh=False",
-    "MaxBFrame=3",
-    "i_bframe_adaptive=1",
-    "i_bframe_bias=0",
-    "i_bframe_pyramid=2",
-    "b_deblocking_filter=True",
-    "i_deblocking_filter_alphac0=0",
-    "i_deblocking_filter_beta=0",
-    "cabac=True",
-    "interlaced=False",
-    "constrained_intra=False",
-    "tff=True",
-    "fake_interlaced=False",
-    "analyze.b_8x8=True",
-    "analyze.b_i4x4=True",
-    "analyze.b_i8x8=True",
-    "analyze.b_p8x8=True",
-    "analyze.b_p16x16=False",
-    "analyze.b_b16x16=False",
-    "analyze.weighted_pred=2",
-    "analyze.weighted_bipred=True",
-    "analyze.direct_mv_pred=1",
-    "analyze.chroma_offset=0",
-    "analyze.me_method=1",
-    "analyze.me_range=16",
-    "analyze.mv_range=-1",
-    "analyze.mv_range_thread=-1",
-    "analyze.subpel_refine=7",
-    "analyze.chroma_me=True",
-    "analyze.mixed_references=True",
-    "analyze.trellis=1",
-    "analyze.psy_rd=1.000000",
-    "analyze.psy_trellis=0.000000",
-    "analyze.fast_pskip=True",
-    "analyze.dct_decimate=True",
-    "analyze.noise_reduction=0",
-    "analyze.psy=True",
-    "analyze.intra_luma=11",
-    "analyze.inter_luma=21",
-    "ratecontrol.rc_method=0",
-    "ratecontrol.qp_constant=0",
-    "ratecontrol.qp_min=10",
-    "ratecontrol.qp_max=51",
-    "ratecontrol.qp_step=4",
-    "ratecontrol.bitrate=0",
-    "ratecontrol.rate_tolerance=1.000000",
-    "ratecontrol.vbv_max_bitrate=0",
-    "ratecontrol.vbv_buffer_size=0",
-    "ratecontrol.vbv_buffer_init=1",
-    "ratecontrol.ip_factor=1.400000",
-    "ratecontrol.pb_factor=1.300000",
-    "ratecontrol.aq_mode=1",
-    "ratecontrol.aq_strength=1.000000",
-    "ratecontrol.mb_tree=True",
-    "ratecontrol.lookahead=40")
-adm.clearVideoFilters()
-adm.addVideoFilter(
-    "shaderLoader",
-    "shaderFile=/opt/rk/avidemux/unfish_gopro_8:7.glsl")
-adm.addVideoFilter(
-    "swscale",
-    "width=616",
-    "height=540",
-    "algo=1",
-    "sourceAR=0",
-    "targetAR=0",
-    "lockAR=False",
-    "roundup=2")
-adm.addVideoFilter(
-    "MplayerDenoise3DHQ",
-    "mode=4",
-    "luma_spatial=4.000000",
-    "chroma_spatial=3.000000",
-    "luma_temporal=6.000000",
-    "chroma_temporal=4.500000")
-adm.setContainer(
-    "MP4",
-    "muxerType=0",
-    "optimize=1",
-    "forceAspectRatio=False",
-    "aspectRatio=1",
-    "displayWidth=1280",
-    "rotation=0",
-    "clockfreq=0")

gopro_8:7/unfish_gopro_8:7.glsl

@@ -5,34 +5,61 @@
 
 #extension GL_ARB_texture_rectangle: enable
 
+// TODO: investigate
+// precision highp float;
+
+// uniforms
 uniform sampler2DRect myTextureY;
 uniform sampler2DRect myTextureU;
 uniform sampler2DRect myTextureV;
 uniform vec2 myResolution;
 uniform float pts;
 
-const vec2 half_pixel = vec2(0.5, 0.5);
+// parameters
-
-const vec2 input_scale = vec2(0.652485, 1.0);
 const float input_fov = 156.0;
-const float output_fov = 119.789529;
+const float output_fov = 124.45;
+const vec2 pixel_scale = vec2(0.652485, 1.0);
+const int subsampling = 4;
 
-vec2 unfish(vec2 coord) {
+// subsampling constants
-    float diameter = sqrt(dot(myResolution, myResolution));
+const float substep = 1.0 / float(subsampling);
-    vec2 center = myResolution * 0.5;
+const float substart = substep * 0.5 - 0.5;
-    vec2 input_position = (coord - center) * input_scale;
+const float subscale = 1.0 / float(subsampling * subsampling);
-    float input_distance = length(input_position);
+
-    float input_len = diameter / radians(input_fov);
+// variables
-    float output_len = diameter / (2.0 * tan(radians(output_fov) * 0.5));
+vec2 center;
-    float unfish_ratio = input_len * atan(input_distance / output_len) / input_distance;
+float diameter;
-    return center + input_position * unfish_ratio;
+float input_len;
+float inv_output_len;
+
+vec4 unfish(const in vec2 coord) {
+    float len = max(0.001, length(coord));
+    vec2 y_coord = center + coord * ((input_len / len) * atan(len * inv_output_len));
+    vec2 uv_coord = y_coord * 0.5;
+    return vec4(
+        texture2DRect(myTextureY, y_coord).r,
+        texture2DRect(myTextureU, uv_coord).r,
+        texture2DRect(myTextureV, uv_coord).r,
+        1.0
+    );
 }
 
 void main() {
-    vec2 y_coord = unfish(gl_TexCoord[0].xy + half_pixel);
+    center = myResolution * 0.5;
-    vec2 uv_coord = y_coord * 0.5;
+    diameter = length(myResolution);
-    vec4 y = texture2DRect(myTextureY, y_coord);
+    input_len = diameter / radians(input_fov);
-    vec4 u = texture2DRect(myTextureU, uv_coord);
+    inv_output_len = (2.0 * tan(radians(output_fov * 0.5))) / diameter;
-    vec4 v = texture2DRect(myTextureV, uv_coord);
+
-    gl_FragColor = vec4(y.r, u.r, v.r, 1.0);
+    vec2 coord = gl_TexCoord[0].xy - center;
+    vec4 pixel = vec4(0.0, 0.0, 0.0, 0.0);
+
+    float x, y = substart;
+    for (int column = 0; column < subsampling; column++, y += substep) {
+        x = substart;
+        for (int row = 0; row < subsampling; row++, x += substep) {
+            pixel += unfish((coord + vec2(x, y)) * pixel_scale);
+        }
+    }
+
+    gl_FragColor = pixel * subscale;
 }

install_gopro_8:7.sh

@@ -1,6 +1,18 @@
 #!/bin/sh
 # RozK
-rm -f ~/.avidemux6/custom/preset_gopro_*
+
-cp gopro_8:7/preset_gopro_* ~/.avidemux6/custom/
+if [ -d ~/.local/share/avidemux6 ]; then
+  mkdir -p ~/.local/share/avidemux6/custom
+  rm -f ~/.local/share/avidemux6/custom/preset_gopro*
+  cp gopro_8:7/preset_gopro* ~/.local/share/avidemux6/custom/
+fi
+
+if [ -d ~/.avidemux6 ]; then
+  mkdir -p ~/.avidemux6/custom
+  rm -f ~/.avidemux6/custom/preset_gopro*
+  cp gopro_8:7/preset_gopro* ~/.avidemux6/custom/
+fi
+
 sudo mkdir -p /opt/rk/avidemux
+sudo rm -f /opt/rk/avidemux/*
 sudo cp gopro_8:7/unfish_gopro_8:7.glsl /opt/rk/avidemux