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/**************************************************************************
*
* Copyright 2009 Younes Manton.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
#include "util/u_math.h"
#include "util/u_debug.h"
#include "vl_csc.h"
/*
* Color space conversion formulas
*
* To convert YCbCr to RGB,
* vec4 ycbcr, rgb
* mat44 csc
* rgb = csc * ycbcr
*
* To calculate the color space conversion matrix csc with ProcAmp adjustments,
* mat44 csc, cstd, procamp, bias
* csc = cstd * (procamp * bias)
*
* Where cstd is a matrix corresponding to one of the color standards (BT.601, BT.709, etc)
* adjusted for the kind of YCbCr -> RGB mapping wanted (1:1, full),
* bias is a matrix corresponding to the kind of YCbCr -> RGB mapping wanted (1:1, full)
*
* To calculate procamp,
* mat44 procamp, hue, saturation, brightness, contrast
* procamp = brightness * (saturation * (contrast * hue))
* Alternatively,
* procamp = saturation * (brightness * (contrast * hue))
*
* contrast
* [ c, 0, 0, 0]
* [ 0, c, 0, 0]
* [ 0, 0, c, 0]
* [ 0, 0, 0, 1]
*
* brightness
* [ 1, 0, 0, b/c]
* [ 0, 1, 0, 0]
* [ 0, 0, 1, 0]
* [ 0, 0, 0, 1]
*
* saturation
* [ 1, 0, 0, 0]
* [ 0, s, 0, 0]
* [ 0, 0, s, 0]
* [ 0, 0, 0, 1]
*
* hue
* [ 1, 0, 0, 0]
* [ 0, cos(h), sin(h), 0]
* [ 0, -sin(h), cos(h), 0]
* [ 0, 0, 0, 1]
*
* procamp
* [ c, 0, 0, b]
* [ 0, c*s*cos(h), c*s*sin(h), 0]
* [ 0, -c*s*sin(h), c*s*cos(h), 0]
* [ 0, 0, 0, 1]
*
* bias
* [ 1, 0, 0, ybias]
* [ 0, 1, 0, cbbias]
* [ 0, 0, 1, crbias]
* [ 0, 0, 0, 1]
*
* csc
* [ c*cstd[ 0], c*cstd[ 1]*s*cos(h) - c*cstd[ 2]*s*sin(h), c*cstd[ 2]*s*cos(h) + c*cstd[ 1]*s*sin(h), cstd[ 3] + cstd[ 0]*(b + c*ybias) + cstd[ 1]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[ 2]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
* [ c*cstd[ 4], c*cstd[ 5]*s*cos(h) - c*cstd[ 6]*s*sin(h), c*cstd[ 6]*s*cos(h) + c*cstd[ 5]*s*sin(h), cstd[ 7] + cstd[ 4]*(b + c*ybias) + cstd[ 5]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[ 6]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
* [ c*cstd[ 8], c*cstd[ 9]*s*cos(h) - c*cstd[10]*s*sin(h), c*cstd[10]*s*cos(h) + c*cstd[ 9]*s*sin(h), cstd[11] + cstd[ 8]*(b + c*ybias) + cstd[ 9]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[10]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
* [ c*cstd[12], c*cstd[13]*s*cos(h) - c*cstd[14]*s*sin(h), c*cstd[14]*s*cos(h) + c*cstd[13]*s*sin(h), cstd[15] + cstd[12]*(b + c*ybias) + cstd[13]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[14]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
*/
/*
* Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
* Y is in [16,235], Cb and Cr are in [16,240]
* R, G, and B are in [16,235]
*/
static const vl_csc_matrix bt_601 =
{
{ 1.0f, 0.0f, 1.371f, 0.0f, },
{ 1.0f, -0.336f, -0.698f, 0.0f, },
{ 1.0f, 1.732f, 0.0f, 0.0f, }
};
/*
* Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
* Y is in [16,235], Cb and Cr are in [16,240]
* R, G, and B are in [0,255]
*/
static const vl_csc_matrix bt_601_full =
{
{ 1.164f, 0.0f, 1.596f, 0.0f, },
{ 1.164f, -0.391f, -0.813f, 0.0f, },
{ 1.164f, 2.018f, 0.0f, 0.0f, }
};
/*
* Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
* Y is in [16,235], Cb and Cr are in [16,240]
* R, G, and B are in [16,235]
*/
static const vl_csc_matrix bt_709 =
{
{ 1.0f, 0.0f, 1.540f, 0.0f, },
{ 1.0f, -0.183f, -0.459f, 0.0f, },
{ 1.0f, 1.816f, 0.0f, 0.0f, }
};
/*
* Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
* Y is in [16,235], Cb and Cr are in [16,240]
* R, G, and B are in [0,255]
*/
static const vl_csc_matrix bt_709_full =
{
{ 1.164f, 0.0f, 1.793f, 0.0f, },
{ 1.164f, -0.213f, -0.534f, 0.0f, },
{ 1.164f, 2.115f, 0.0f, 0.0f, }
};
static const vl_csc_matrix smpte240m =
{
{ 1.0f, 0.0f, 1.582f, 0.0f, },
{ 1.0f, -0.228f, -0.478f, 0.0f, },
{ 1.0f, 1.833f, 0.0f, 0.0f, }
};
static const vl_csc_matrix smpte240m_full =
{
{ 1.164f, 0.0f, 1.794f, 0.0f, },
{ 1.164f, -0.258f, -0.543f, 0.0f, },
{ 1.164f, 2.079f, 0.0f, 0.0f, }
};
static const vl_csc_matrix identity =
{
{ 1.0f, 0.0f, 0.0f, 0.0f, },
{ 0.0f, 1.0f, 0.0f, 0.0f, },
{ 0.0f, 0.0f, 1.0f, 0.0f, }
};
const struct vl_procamp vl_default_procamp = {
0.0f, /* brightness */
1.0f, /* contrast */
1.0f, /* saturation */
0.0f /* hue */
};
void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
struct vl_procamp *procamp,
bool full_range,
vl_csc_matrix *matrix)
{
float ybias = full_range ? -16.0f/255.0f : 0.0f;
float cbbias = -128.0f/255.0f;
float crbias = -128.0f/255.0f;
const struct vl_procamp *p = procamp ? procamp : &vl_default_procamp;
float c = p->contrast;
float s = p->saturation;
float b = p->brightness;
float h = p->hue;
const vl_csc_matrix *cstd;
assert(matrix);
switch (cs) {
case VL_CSC_COLOR_STANDARD_BT_601:
cstd = full_range ? &bt_601_full : &bt_601;
break;
case VL_CSC_COLOR_STANDARD_BT_709:
cstd = full_range ? &bt_709_full : &bt_709;
break;
case VL_CSC_COLOR_STANDARD_SMPTE_240M:
cstd = full_range ? &smpte240m_full : &smpte240m;
break;
case VL_CSC_COLOR_STANDARD_IDENTITY:
default:
assert(cs == VL_CSC_COLOR_STANDARD_IDENTITY);
memcpy(matrix, identity, sizeof(vl_csc_matrix));
return;
}
(*matrix)[0][0] = c * (*cstd)[0][0];
(*matrix)[0][1] = c * (*cstd)[0][1] * s * cosf(h) - c * (*cstd)[0][2] * s * sinf(h);
(*matrix)[0][2] = c * (*cstd)[0][2] * s * cosf(h) + c * (*cstd)[0][1] * s * sinf(h);
(*matrix)[0][3] = (*cstd)[0][3] + (*cstd)[0][0] * (b + c * ybias) +
(*cstd)[0][1] * (c * cbbias * s * cosf(h) + c * crbias * s * sinf(h)) +
(*cstd)[0][2] * (c * crbias * s * cosf(h) - c * cbbias * s * sinf(h));
(*matrix)[1][0] = c * (*cstd)[1][0];
(*matrix)[1][1] = c * (*cstd)[1][1] * s * cosf(h) - c * (*cstd)[1][2] * s * sinf(h);
(*matrix)[1][2] = c * (*cstd)[1][2] * s * cosf(h) + c * (*cstd)[1][1] * s * sinf(h);
(*matrix)[1][3] = (*cstd)[1][3] + (*cstd)[1][0] * (b + c * ybias) +
(*cstd)[1][1] * (c * cbbias * s * cosf(h) + c * crbias * s * sinf(h)) +
(*cstd)[1][2] * (c * crbias * s * cosf(h) - c * cbbias * s * sinf(h));
(*matrix)[2][0] = c * (*cstd)[2][0];
(*matrix)[2][1] = c * (*cstd)[2][1] * s * cosf(h) - c * (*cstd)[2][2] * s * sinf(h);
(*matrix)[2][2] = c * (*cstd)[2][2] * s * cosf(h) + c * (*cstd)[2][1] * s * sinf(h);
(*matrix)[2][3] = (*cstd)[2][3] + (*cstd)[2][0] * (b + c * ybias) +
(*cstd)[2][1] * (c * cbbias * s * cosf(h) + c * crbias * s * sinf(h)) +
(*cstd)[2][2] * (c * crbias * s * cosf(h) - c * cbbias * s * sinf(h));
}
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