update readme and add installation instructions

README.md

@@ -2,5 +2,20 @@
 
 Shaders for Avidemux with OpenGL support
 
-```unfish_gopro_8-7_wide_hypersmooth-off.glsl```  
+## gopro_8:7 - Fisheye removal for GoPro 11+, 8:7 ratio
-Fisheye removal for GoPro, 8:7 aspect ratio, wide FOV, HyperSmooth off
+- unfish_gopro_8:7.glsl  
+Shader for fisheye removal
+
+- preset_gopro_8:7_1080.py  
+Preset for mp4, 1656x1080, constant bitrate
+
+- compute_gopro_8:7.py  
+Script to compute output FOV and frame widening
+
+### Installation for BSD/GNU-Linux systems:
+- Copy the preset to ~/.avidemux6/custom/
+- Copy the shader to /opt/rk/avidemux/ (or edit the preset to set the path)  
+
+_For commercial OS's, figure out the paths yourself :)_
+### Usage:
+Load and edit video(s), select "Custom/preset_gopro_8:7_1080" in the menu and save the video.

gopro_8:7/compute_gopro_8:7.py

@@ -0,0 +1,34 @@
+# RozK
+# Computes fisheye removal parameters for GoPro 11+, 8:7 ratio, without hypersmooth,
+# keeping the vertical FOV and widening the frame to preserve the diagonal FOV
+
+# https://community.gopro.com/s/article/HERO11-Black-Mini-Digital-Lenses-FOV-Information?language=fr
+
+import math
+
+frame_width = 8
+frame_height = 7
+
+input_vertical_fov = 108.0
+input_diagonal_fov = 156.0
+
+input_vertical_length = math.radians(input_vertical_fov * 0.5)
+input_diagonal_length = math.radians(input_diagonal_fov * 0.5)
+
+output_horizontal_length = math.sqrt((input_diagonal_length ** 2) / (input_vertical_length ** 2))
+output_diagonal_length = math.hypot(output_horizontal_length, input_vertical_length)
+output_diagonal_fov = math.degrees(math.atan(output_diagonal_length)) * 2.0
+
+output_ratio = output_horizontal_length / input_vertical_length
+
+print("Output FOV   = %f" % output_diagonal_fov)
+print("Output Ratio = %f" % output_ratio)
+print("= Resolutions =====================")
+
+def width_rounded_8(height):
+    width = int(round(height * output_ratio))
+    return ((width + 4) // 8) * 8
+
+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_1080.py

@@ -0,0 +1,18 @@
+#PY  <- Needed to identify #
+
+# Custom preset for GoPro, 8:7 ratio, without hypersmooth, output widened scaled to Full HD (1080p)
+
+adm = Avidemux()
+adm.videoCodec("x264", "useAdvancedConfiguration=False", "general.params=CBR=16384", "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.addVideoFilter("shaderLoader", "shaderFile=/opt/rk/avidemux/unfish_gopro_8:7.glsl")
+adm.addVideoFilter("swscale", "width=1656", "height=1080", "algo=1", "sourceAR=0", "targetAR=0", "lockAR=False", "roundup=2")
+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

@@ -1,5 +1,6 @@
 // RozK
-// Adapted from https://github.com/duducosmos/defisheye,
+// Fisheye removal for GoPro 11+, 8:7 ratio, without hypersmooth
+// Adapted from https://github.com/duducosmos/defisheye
 // itself based on http://www.fmwconcepts.com/imagemagick/defisheye/index.php
 
 #extension GL_ARB_texture_rectangle: enable
@@ -11,18 +12,17 @@ uniform vec2 myResolution;
 uniform float pts;
 
 const vec2 half_pixel = vec2(0.5, 0.5);
-const float pi = 3.1415927;
 
 const float input_fov = 156.0;
-const float output_fov = 120.0;
+const float output_fov = 119.789529;
 
 vec2 unfish(vec2 coord) {
     float diameter = sqrt(dot(myResolution, myResolution));
     vec2 center = myResolution * 0.5;
     vec2 position = coord - center;
     float input_distance = length(position);
-    float input_foc = diameter * 180.0 / (input_fov * pi);
+    float input_foc = diameter / radians(input_fov);
-    float output_foc = diameter / (2.0 * tan(output_fov * pi / 360.0));
+    float output_foc = diameter / (2.0 * tan(radians(output_fov) * 0.5));
     return center + position * (input_foc * atan(input_distance / output_foc) / input_distance);
 }