return (0.5 - local_chroma_pos) / resolution;
}
+// Given <ycbcr_format>, compute the values needed to turn Y'CbCr into R'G'B';
+// first subtract the returned offset, then left-multiply the returned matrix
+// (the scaling is already folded into it).
+void compute_ycbcr_matrix(YCbCrFormat ycbcr_format, float* offset, Matrix3d* ycbcr_to_rgb)
+{
+ double coeff[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.
+ *ycbcr_to_rgb = rgb_to_ycbcr.inverse();
+
+ // Fold in the scaling.
+ *ycbcr_to_rgb *= Map<const Vector3d>(scale).asDiagonal();
+}
+
} // namespace
YCbCrInput::YCbCrInput(const ImageFormat &image_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