#include "effect_util.h"
#include "resource_pool.h"
#include "util.h"
+#include "ycbcr.h"
#include "ycbcr_input.h"
using namespace Eigen;
namespace movit {
-namespace {
-
-// OpenGL has texel center in (0.5, 0.5), but different formats have
-// chroma in various other places. If luma samples are X, the chroma
-// sample is *, and subsampling is 3x3, the situation with chroma
-// center in (0.5, 0.5) looks approximately like this:
-//
-// X X
-// *
-// X X
-//
-// If, on the other hand, chroma center is in (0.0, 0.5) (common
-// for e.g. MPEG-4), the figure changes to:
-//
-// X X
-// *
-// X X
-//
-// In other words, (0.0, 0.0) means that the chroma sample is exactly
-// co-sited on top of the top-left luma sample. Note, however, that
-// this is _not_ 0.5 texels to the left, since the OpenGL's texel center
-// is in (0.5, 0.5); it is in (0.25, 0.25). In a sense, the four luma samples
-// define a square where chroma position (0.0, 0.0) is in texel position
-// (0.25, 0.25) and chroma position (1.0, 1.0) is in texel position (0.75, 0.75)
-// (the outer border shows the borders of the texel itself, ie. from
-// (0, 0) to (1, 1)):
-//
-// ---------
-// | |
-// | X---X |
-// | | * | |
-// | X---X |
-// | |
-// ---------
-//
-// Also note that if we have no subsampling, the square will have zero
-// area and the chroma position does not matter at all.
-float compute_chroma_offset(float pos, unsigned subsampling_factor, unsigned resolution)
-{
- float local_chroma_pos = (0.5 + pos * (subsampling_factor - 1)) / subsampling_factor;
- return (0.5 - local_chroma_pos) / resolution;
-}
-
-} // namespace
-
YCbCrInput::YCbCrInput(const ImageFormat &image_format,
const YCbCrFormat &ycbcr_format,
unsigned width, unsigned height)
: image_format(image_format),
ycbcr_format(ycbcr_format),
- needs_mipmaps(false),
width(width),
height(height),
resource_pool(NULL)
heights[2] = height / ycbcr_format.chroma_subsampling_y;
pixel_data[0] = pixel_data[1] = pixel_data[2] = NULL;
-
- register_int("needs_mipmaps", &needs_mipmaps);
}
YCbCrInput::~YCbCrInput()
string YCbCrInput::output_fragment_shader()
{
- float coeff[3], offset[3], scale[3];
-
- switch (ycbcr_format.luma_coefficients) {
- case YCBCR_REC_601:
- // Rec. 601, page 2.
- coeff[0] = 0.299;
- coeff[1] = 0.587;
- coeff[2] = 0.114;
- break;
-
- case YCBCR_REC_709:
- // Rec. 709, page 19.
- coeff[0] = 0.2126;
- coeff[1] = 0.7152;
- coeff[2] = 0.0722;
- break;
-
- case YCBCR_REC_2020:
- // Rec. 2020, page 4.
- coeff[0] = 0.2627;
- coeff[1] = 0.6780;
- coeff[2] = 0.0593;
- break;
-
- default:
- assert(false);
- }
-
- if (ycbcr_format.full_range) {
- offset[0] = 0.0 / 255.0;
- offset[1] = 128.0 / 255.0;
- offset[2] = 128.0 / 255.0;
-
- scale[0] = 1.0;
- scale[1] = 1.0;
- scale[2] = 1.0;
- } else {
- // Rec. 601, page 4; Rec. 709, page 19; Rec. 2020, page 4.
- offset[0] = 16.0 / 255.0;
- offset[1] = 128.0 / 255.0;
- offset[2] = 128.0 / 255.0;
-
- scale[0] = 255.0 / 219.0;
- scale[1] = 255.0 / 224.0;
- scale[2] = 255.0 / 224.0;
- }
-
- // Matrix to convert RGB to YCbCr. See e.g. Rec. 601.
- Matrix3d rgb_to_ycbcr;
- rgb_to_ycbcr(0,0) = coeff[0];
- rgb_to_ycbcr(0,1) = coeff[1];
- rgb_to_ycbcr(0,2) = coeff[2];
-
- float cb_fac = (224.0 / 219.0) / (coeff[0] + coeff[1] + 1.0f - coeff[2]);
- rgb_to_ycbcr(1,0) = -coeff[0] * cb_fac;
- rgb_to_ycbcr(1,1) = -coeff[1] * cb_fac;
- rgb_to_ycbcr(1,2) = (1.0f - coeff[2]) * cb_fac;
-
- float cr_fac = (224.0 / 219.0) / (1.0f - coeff[0] + coeff[1] + coeff[2]);
- rgb_to_ycbcr(2,0) = (1.0f - coeff[0]) * cr_fac;
- rgb_to_ycbcr(2,1) = -coeff[1] * cr_fac;
- rgb_to_ycbcr(2,2) = -coeff[2] * cr_fac;
-
- // Inverting the matrix gives us what we need to go from YCbCr back to RGB.
- Matrix3d ycbcr_to_rgb = rgb_to_ycbcr.inverse();
+ float offset[3];
+ Matrix3d ycbcr_to_rgb;
+ compute_ycbcr_matrix(ycbcr_format, offset, &ycbcr_to_rgb);
string frag_shader;
frag_shader = output_glsl_mat3("PREFIX(inv_ycbcr_matrix)", ycbcr_to_rgb);
-
- char buf[256];
- sprintf(buf, "const vec3 PREFIX(offset) = vec3(%.8f, %.8f, %.8f);\n",
- offset[0], offset[1], offset[2]);
- frag_shader += buf;
-
- sprintf(buf, "const vec3 PREFIX(scale) = vec3(%.8f, %.8f, %.8f);\n",
- scale[0], scale[1], scale[2]);
- frag_shader += buf;
+ frag_shader += output_glsl_vec3("PREFIX(offset)", offset[0], offset[1], offset[2]);
float cb_offset_x = compute_chroma_offset(
ycbcr_format.cb_x_position, ycbcr_format.chroma_subsampling_x, widths[1]);
float cb_offset_y = compute_chroma_offset(
ycbcr_format.cb_y_position, ycbcr_format.chroma_subsampling_y, heights[1]);
- sprintf(buf, "const vec2 PREFIX(cb_offset) = vec2(%.8f, %.8f);\n",
- cb_offset_x, cb_offset_y);
- frag_shader += buf;
+ frag_shader += output_glsl_vec2("PREFIX(cb_offset)", cb_offset_x, cb_offset_y);
float cr_offset_x = compute_chroma_offset(
ycbcr_format.cr_x_position, ycbcr_format.chroma_subsampling_x, widths[2]);
float cr_offset_y = compute_chroma_offset(
ycbcr_format.cr_y_position, ycbcr_format.chroma_subsampling_y, heights[2]);
- sprintf(buf, "const vec2 PREFIX(cr_offset) = vec2(%.8f, %.8f);\n",
- cr_offset_x, cr_offset_y);
- frag_shader += buf;
+ frag_shader += output_glsl_vec2("PREFIX(cr_offset)", cr_offset_x, cr_offset_y);
frag_shader += read_file("ycbcr_input.frag");
return frag_shader;
}
}
+bool YCbCrInput::set_int(const std::string& key, int value)
+{
+ if (key == "needs_mipmaps") {
+ // We currently do not support this.
+ return (value == 0);
+ }
+ return Effect::set_int(key, value);
+}
+
} // namespace movit
projects / movit / blobdiff