In ResampleEffect, precompute the Lanczos function into a table.
[movit] / ycbcr_input.cpp
index dc5e4d9..7f58f3f 100644 (file)
@@ -8,6 +8,7 @@
 #include "effect_util.h"
 #include "resource_pool.h"
 #include "util.h"
+#include "ycbcr.h"
 #include "ycbcr_input.h"
 
 using namespace Eigen;
@@ -15,57 +16,13 @@ using namespace std;
 
 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)
+                       unsigned width, unsigned height,
+                       YCbCrInputSplitting ycbcr_input_splitting)
        : image_format(image_format),
          ycbcr_format(ycbcr_format),
-         needs_mipmaps(false),
+         ycbcr_input_splitting(ycbcr_input_splitting),
          width(width),
          height(height),
          resource_pool(NULL)
@@ -85,12 +42,22 @@ YCbCrInput::YCbCrInput(const ImageFormat &image_format,
 
        pixel_data[0] = pixel_data[1] = pixel_data[2] = NULL;
 
-       register_int("needs_mipmaps", &needs_mipmaps);
+       register_uniform_sampler2d("tex_y", &uniform_tex_y);
+
+       if (ycbcr_input_splitting == YCBCR_INPUT_SPLIT_Y_AND_CBCR) {
+               num_channels = 2;
+               register_uniform_sampler2d("tex_cbcr", &uniform_tex_cb);
+       } else {
+               assert(ycbcr_input_splitting == YCBCR_INPUT_PLANAR);
+               num_channels = 3;
+               register_uniform_sampler2d("tex_cb", &uniform_tex_cb);
+               register_uniform_sampler2d("tex_cr", &uniform_tex_cr);
+       }
 }
 
 YCbCrInput::~YCbCrInput()
 {
-       for (unsigned channel = 0; channel < 3; ++channel) {
+       for (unsigned channel = 0; channel < num_channels; ++channel) {
                if (texture_num[channel] != 0) {
                        resource_pool->release_2d_texture(texture_num[channel]);
                }
@@ -99,13 +66,22 @@ YCbCrInput::~YCbCrInput()
 
 void YCbCrInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
 {
-       for (unsigned channel = 0; channel < 3; ++channel) {
+       for (unsigned channel = 0; channel < num_channels; ++channel) {
                glActiveTexture(GL_TEXTURE0 + *sampler_num + channel);
                check_error();
 
                if (texture_num[channel] == 0) {
+                       GLenum format, internal_format;
+                       if (channel == 1 && ycbcr_input_splitting == YCBCR_INPUT_SPLIT_Y_AND_CBCR) {
+                               format = GL_RG;
+                               internal_format = GL_RG8;
+                       } else {
+                               format = GL_RED;
+                               internal_format = GL_R8;
+                       }
+
                        // (Re-)upload the texture.
-                       texture_num[channel] = resource_pool->create_2d_texture(GL_R8, widths[channel], heights[channel]);
+                       texture_num[channel] = resource_pool->create_2d_texture(internal_format, widths[channel], heights[channel]);
                        glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
                        check_error();
                        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -116,7 +92,7 @@ void YCbCrInput::set_gl_state(GLuint glsl_program_num, const string& prefix, uns
                        check_error();
                        glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch[channel]);
                        check_error();
-                       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, widths[channel], heights[channel], GL_RED, GL_UNSIGNED_BYTE, pixel_data[channel]);
+                       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, widths[channel], heights[channel], format, GL_UNSIGNED_BYTE, pixel_data[channel]);
                        check_error();
                        glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
                        check_error();
@@ -134,109 +110,46 @@ void YCbCrInput::set_gl_state(GLuint glsl_program_num, const string& prefix, uns
        check_error();
 
        // Bind samplers.
-       set_uniform_int(glsl_program_num, prefix, "tex_y", *sampler_num + 0);
-       set_uniform_int(glsl_program_num, prefix, "tex_cb", *sampler_num + 1);
-       set_uniform_int(glsl_program_num, prefix, "tex_cr", *sampler_num + 2);
+       uniform_tex_y = *sampler_num + 0;
+       uniform_tex_cb = *sampler_num + 1;
+       if (ycbcr_input_splitting == YCBCR_INPUT_PLANAR) {
+               uniform_tex_cr = *sampler_num + 2;
+       }
 
-       *sampler_num += 3;
+       *sampler_num += num_channels;
 }
 
 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);
+
+       if (ycbcr_input_splitting == YCBCR_INPUT_SPLIT_Y_AND_CBCR) {
+               char buf[256];
+               snprintf(buf, sizeof(buf), "#define CB_CR_SAME_TEXTURE 1\n#define CB_CR_OFFSETS_EQUAL %d\n",
+                       (fabs(ycbcr_format.cb_x_position - ycbcr_format.cr_x_position) < 1e-6));
+               frag_shader += buf;
+       } else {
+               frag_shader += "#define CB_CR_SAME_TEXTURE 0\n";
+       }
 
        frag_shader += read_file("ycbcr_input.frag");
        return frag_shader;
@@ -252,4 +165,13 @@ void YCbCrInput::invalidate_pixel_data()
        }
 }
 
+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