Assuming that you have a linux distribution:
- flash image as usual on a SD card
- mount first partition of sd card on your linux machine
# mount /dev/mmcblk0p1 /some_mountpoints
- explode libreelec filesystem with squashfs tools
# mkdir tmp_dir
# cd tmp_dir
# unsquashfs /some_mountpoints/SYSTEM
at this point under squashfs-root you can find the exploded filesystem of libreelec.
- replace file squashfs-root/usr/share/kodi/system/shaders/GLES/2.0/gles_yuv2rgb_basic.frag
/*
* Copyright (C) 2010-2013 Team XBMC
* http://xbmc.org
*
* This Program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This Program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNES FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with XBMC; see the file COPYING. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#version 100
precision mediump float;
uniform sampler2D m_sampY;
uniform sampler2D m_sampU;
uniform sampler2D m_sampV;
varying vec2 m_cordY;
varying vec2 m_cordU;
varying vec2 m_cordV;
uniform vec2 m_step;
uniform mat4 m_yuvmat;
uniform mat3 m_primMat;
uniform float m_gammaDstInv;
uniform float m_gammaSrc;
uniform float m_toneP1;
uniform vec3 m_coefsDst;
uniform float m_alpha;
void main()
{
vec4 rgb;
vec4 yuv;
#if defined(XBMC_YV12) || defined(XBMC_NV12)
yuv = vec4(texture2D(m_sampY, m_cordY).r,
texture2D(m_sampU, m_cordU).g,
texture2D(m_sampV, m_cordV).a,
1.0);
#elif defined(XBMC_NV12_RRG)
yuv = vec4(texture2D(m_sampY, m_cordY).r,
texture2D(m_sampU, m_cordU).r,
texture2D(m_sampV, m_cordV).g,
1.0);
#endif
/* START PATCH: DISABLE BT.709 colorspace conversion
rgb = m_yuvmat * yuv;
rgb.a = m_alpha;
#if defined(XBMC_COL_CONVERSION)
rgb.rgb = pow(max(vec3(0), rgb.rgb), vec3(m_gammaSrc));
rgb.rgb = max(vec3(0), m_primMat * rgb.rgb);
rgb.rgb = pow(rgb.rgb, vec3(m_gammaDstInv));
#if defined(XBMC_TONE_MAPPING)
float luma = dot(rgb.rgb, m_coefsDst);
rgb.rgb *= tonemap(luma) / luma;
#endif
#endif
END PATCH: DISABLE BT.709 colorspace conversion */
gl_FragColor = vec4(vec3(m_yuvmat * yuv),m_alpha);
}
Display More
- replace file squashfs-root/usr/share/kodi/system/shaders/GLES/2.0/gles_yuv2rgb_bob.frag
/*
* Copyright (C) 2010-2013 Team XBMC
* http://xbmc.org
*
* This Program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This Program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNES FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with XBMC; see the file COPYING. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#version 100
precision highp float;
uniform sampler2D m_sampY;
uniform sampler2D m_sampU;
uniform sampler2D m_sampV;
varying vec2 m_cordY;
varying vec2 m_cordU;
varying vec2 m_cordV;
uniform float m_alpha;
uniform mat4 m_yuvmat;
uniform float m_stepX;
uniform float m_stepY;
uniform int m_field;
uniform mat3 m_primMat;
uniform float m_gammaDstInv;
uniform float m_gammaSrc;
uniform float m_toneP1;
uniform vec3 m_coefsDst;
void main()
{
vec4 rgb;
vec2 offsetY;
vec2 offsetU;
vec2 offsetV;
float temp1 = mod(m_cordY.y, 2.0 * m_stepY);
offsetY = m_cordY;
offsetU = m_cordU;
offsetV = m_cordV;
offsetY.y -= (temp1 - m_stepY / 2.0 + float(m_field) * m_stepY);
offsetU.y -= (temp1 - m_stepY / 2.0 + float(m_field) * m_stepY) / 2.0;
offsetV.y -= (temp1 - m_stepY / 2.0 + float(m_field) * m_stepY) / 2.0;
float bstep = step(m_stepY, temp1);
// Blend missing line
vec2 below, below, below;
belowY.x = offsetY.x;
belowY.y = offsetY.y + (2.0 * m_stepY * bstep);
belowU.x = offsetU.x;
belowU.y = offsetU.y + (m_stepY * bstep);
belowV.x = offsetV.x;
belowV.y = offsetV.y + (m_stepY * bstep);
vec4 rgbAbove;
vec4 rgbBelow;
vec4 yuvAbove;
vec4 yuvBelow;
yuvAbove = vec4(texture2D(m_sampY, offsetY).r, texture2D(m_sampU, offsetU).g, texture2D(m_sampV, offsetV).a, 1.0);
rgbAbove = m_yuvmat * yuvAbove;
rgbAbove.a = m_alpha;
yuvBelow = vec4(texture2D(m_sampY, belowY).r, texture2D(m_sampU, belowU).g, texture2D(m_sampV, belowV).a, 1.0);
rgbBelow = m_yuvmat * yuvBelow;
rgbBelow.a = m_alpha;
rgb = mix(rgb, rgbBelow, 0.5);
/* START PATCH: DISABLE BT.709 COLOR CONVERSION
#if defined(XBMC_COL_CONVERSION)
rgb.rgb = pow(max(vec3(0), rgb.rgb), vec3(m_gammaSrc));
rgb.rgb = max(vec3(0), m_primMat * rgb.rgb);
rgb.rgb = pow(rgb.rgb, vec3(m_gammaDstInv));
#if defined(XBMC_TONE_MAPPING)
float luma = dot(rgb.rgb, m_coefsDst);
rgb.rgb *= tonemap(luma) / luma;
#endif
#endif
END PATCH: DISABLE BT.709 COLOR CONVERSION */
gl_FragColor = rgb;
}
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- repackage squash filesystem, copy to sd card and umount
# mksquashfs squashfs-root/ SYSTEM -comp gzip
# cp SYSTEM /some_mountpoints/SYSTEM
# umount /dev/mmcblk0p1
that's all.
NB: This patch disables BT.709 color conversion that is slow on my mali 400 because it's using the pow math function.
