output_color_space[effect] = output_color_space[last_added_effect()];
}
-// Set the "use_srgb_texture_format" option on all inputs that feed into this node,
-// and update the output_gamma_curve[] map as we go.
-//
-// NOTE: We assume that the only way we could actually get GAMMA_sRGB from an
-// effect (except from GammaCompressionCurve, which should never be inserted
-// into a chain when this is called) is by pass-through from a texture.
-// Thus, we can simply feed the flag up towards all inputs.
-void EffectChain::set_use_srgb_texture_format(Effect *effect)
+void EffectChain::find_all_nonlinear_inputs(Effect *effect,
+ std::vector<Input *> *nonlinear_inputs,
+ std::vector<Effect *> *intermediates)
{
assert(output_gamma_curve.count(effect) != 0);
- assert(output_gamma_curve[effect] == GAMMA_sRGB);
+ if (output_gamma_curve[effect] == GAMMA_LINEAR) {
+ return;
+ }
if (effect->num_inputs() == 0) {
- effect->set_int("use_srgb_texture_format", 1);
+ nonlinear_inputs->push_back(static_cast<Input *>(effect));
} else {
+ intermediates->push_back(effect);
+
assert(incoming_links.count(effect) == 1);
std::vector<Effect *> deps = incoming_links[effect];
assert(effect->num_inputs() == deps.size());
for (unsigned i = 0; i < deps.size(); ++i) {
- set_use_srgb_texture_format(deps[i]);
- assert(output_gamma_curve[deps[i]] == GAMMA_LINEAR);
+ find_all_nonlinear_inputs(deps[i], nonlinear_inputs, intermediates);
}
}
- output_gamma_curve[effect] = GAMMA_LINEAR;
}
Effect *EffectChain::normalize_to_linear_gamma(Effect *input)
{
- assert(output_gamma_curve.count(input) != 0);
- if (output_gamma_curve[input] == GAMMA_sRGB) {
- // TODO: check if the extension exists
- set_use_srgb_texture_format(input);
- output_gamma_curve[input] = GAMMA_LINEAR;
+ // Find out if all the inputs can be set to deliver sRGB inputs.
+ // If so, we can just ask them to do that instead of inserting a
+ // (possibly expensive) conversion operation.
+ //
+ // NOTE: We assume that effects generally don't mess with the gamma
+ // curve (except GammaCompressionEffect, which should never be
+ // inserted into a chain when this is called), so that we can just
+ // update the output gamma as we go.
+ //
+ // TODO: Setting this flag for one source might confuse a different
+ // part of the pipeline using the same source.
+ std::vector<Input *> nonlinear_inputs;
+ std::vector<Effect *> intermediates;
+ find_all_nonlinear_inputs(input, &nonlinear_inputs, &intermediates);
+
+ bool all_ok = true;
+ for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
+ all_ok &= nonlinear_inputs[i]->can_output_linear_gamma();
+ }
+
+ if (all_ok) {
+ for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
+ bool ok = nonlinear_inputs[i]->set_int("output_linear_gamma", 1);
+ assert(ok);
+ output_gamma_curve[nonlinear_inputs[i]] = GAMMA_LINEAR;
+ }
+ for (unsigned i = 0; i < intermediates.size(); ++i) {
+ output_gamma_curve[intermediates[i]] = GAMMA_LINEAR;
+ }
return input;
- } else {
- GammaExpansionEffect *gamma_conversion = new GammaExpansionEffect();
- gamma_conversion->set_int("source_curve", output_gamma_curve[input]);
- std::vector<Effect *> inputs;
- inputs.push_back(input);
- gamma_conversion->add_self_to_effect_chain(this, inputs);
- output_gamma_curve[gamma_conversion] = GAMMA_LINEAR;
- return gamma_conversion;
}
+
+ // OK, that didn't work. Insert a conversion effect.
+ GammaExpansionEffect *gamma_conversion = new GammaExpansionEffect();
+ gamma_conversion->set_int("source_curve", output_gamma_curve[input]);
+ std::vector<Effect *> inputs;
+ inputs.push_back(input);
+ gamma_conversion->add_self_to_effect_chain(this, inputs);
+ output_gamma_curve[gamma_conversion] = GAMMA_LINEAR;
+ return gamma_conversion;
}
Effect *EffectChain::normalize_to_srgb(Effect *input)
std::vector<Effect *> effects; // In order.
};
- void set_use_srgb_texture_format(Effect *effect);
+ void find_all_nonlinear_inputs(Effect *effect,
+ std::vector<Input *> *nonlinear_inputs,
+ std::vector<Effect *> *intermediates);
Effect *normalize_to_linear_gamma(Effect *input);
Effect *normalize_to_srgb(Effect *input);
: image_format(image_format),
needs_update(false),
finalized(false),
- use_srgb_texture_format(false),
+ output_linear_gamma(false),
needs_mipmaps(false),
width(width),
height(height),
pitch(width)
{
- register_int("use_srgb_texture_format", &use_srgb_texture_format);
+ register_int("output_linear_gamma", &output_linear_gamma);
register_int("needs_mipmaps", &needs_mipmaps);
}
{
// Translate the input format to OpenGL's enums.
GLenum internal_format;
- if (use_srgb_texture_format) {
+ if (output_linear_gamma) {
internal_format = GL_SRGB8;
} else {
internal_format = GL_RGBA8;
// mipmap generation) at that point.
void finalize();
+ // TODO: Check that we actually have the required extension.
+ virtual bool can_output_linear_gamma() const { return true; }
+
std::string output_fragment_shader();
// Uploads the texture if it has changed since last time.
void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
- ColorSpace get_color_space() { return image_format.color_space; }
- GammaCurve get_gamma_curve() { return image_format.gamma_curve; }
+ ColorSpace get_color_space() const { return image_format.color_space; }
+ GammaCurve get_gamma_curve() const { return image_format.gamma_curve; }
// Tells the input where to fetch the actual pixel data. Note that if you change
// this data, you must either call set_pixel_data() again (using the same pointer
GLenum format;
GLuint pbo, texture_num;
bool needs_update, finalized;
- int use_srgb_texture_format, needs_mipmaps;
+ int output_linear_gamma, needs_mipmaps;
unsigned width, height, pitch, bytes_per_pixel;
const unsigned char *pixel_data;
};
GAMMA_REC_709 = 2, // Same as Rec. 601.
};
+enum YCbCrLumaCoefficients {
+ YCBCR_REC_601 = 0,
+ YCBCR_REC_709 = 1,
+};
+
struct ImageFormat {
MovitPixelFormat pixel_format;
ColorSpace color_space;
// mipmap generation) at that point.
virtual void finalize() = 0;
- virtual ColorSpace get_color_space() = 0;
- virtual GammaCurve get_gamma_curve() = 0;
+ // Whether this input can deliver linear gamma directly if it's
+ // asked to. (If so, set the parameter “output_linear_gamma”
+ // to activate it.)
+ virtual bool can_output_linear_gamma() const = 0;
+
+ virtual ColorSpace get_color_space() const = 0;
+ virtual GammaCurve get_gamma_curve() const = 0;
};
#endif // !defined(_INPUT_H)
--- /dev/null
+#define GL_GLEXT_PROTOTYPES 1
+
+#include <string.h>
+#include <GL/gl.h>
+#include <GL/glext.h>
+#include <assert.h>
+
+#include "ycbcr_input.h"
+#include "util.h"
+
+YCbCrInput::YCbCrInput(const ImageFormat &image_format,
+ const YCbCrFormat &ycbcr_format,
+ unsigned width, unsigned height)
+ : image_format(image_format),
+ ycbcr_format(ycbcr_format),
+ needs_update(false),
+ finalized(false),
+ needs_mipmaps(false),
+ width(width),
+ height(height)
+{
+ pitch[0] = pitch[1] = pitch[2] = width;
+
+ assert(width % ycbcr_format.chroma_subsampling_x == 0);
+ widths[0] = width;
+ widths[1] = width / ycbcr_format.chroma_subsampling_x;
+ widths[2] = width / ycbcr_format.chroma_subsampling_x;
+
+ assert(height % ycbcr_format.chroma_subsampling_y == 0);
+ heights[0] = height;
+ heights[1] = height / ycbcr_format.chroma_subsampling_y;
+ heights[2] = height / ycbcr_format.chroma_subsampling_y;
+
+ register_int("needs_mipmaps", &needs_mipmaps);
+}
+
+void YCbCrInput::finalize()
+{
+ // Create PBOs to hold the textures holding the input image, and then the texture itself.
+ glGenBuffers(3, pbos);
+ check_error();
+ glGenTextures(3, texture_num);
+ check_error();
+
+ for (unsigned channel = 0; channel < 3; ++channel) {
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbos[channel]);
+ check_error();
+ glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, pitch[channel] * heights[channel], NULL, GL_STREAM_DRAW);
+ check_error();
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
+ check_error();
+
+ glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
+ check_error();
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+ check_error();
+ glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch[channel]);
+ check_error();
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE8, widths[channel], heights[channel], 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, NULL);
+ check_error();
+ glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+ check_error();
+ }
+
+ needs_update = false;
+ finalized = true;
+}
+
+void YCbCrInput::set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num)
+{
+ for (unsigned channel = 0; channel < 3; ++channel) {
+ glActiveTexture(GL_TEXTURE0 + *sampler_num + channel);
+ check_error();
+ glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
+ check_error();
+
+ if (needs_update) {
+ // Copy the pixel data into the PBO.
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbos[channel]);
+ check_error();
+ void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
+ memcpy(mapped_pbo, pixel_data[channel], pitch[channel] * heights[channel]);
+ glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
+ check_error();
+
+ // Re-upload the texture from the PBO.
+ glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch[channel]);
+ check_error();
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, widths[channel], heights[channel], GL_LUMINANCE, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
+ check_error();
+ glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+ check_error();
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+ check_error();
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+ check_error();
+ glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
+ 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);
+
+ *sampler_num += 3;
+ needs_update = false;
+}
+
+std::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;
+ 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.
+ 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.
+ Matrix3x3 rgb_to_ycbcr;
+ rgb_to_ycbcr[0] = coeff[0];
+ rgb_to_ycbcr[3] = coeff[1];
+ rgb_to_ycbcr[6] = coeff[2];
+
+ float cb_fac = (224.0 / 219.0) / (coeff[0] + coeff[1] + 1.0f - coeff[2]);
+ rgb_to_ycbcr[1] = -coeff[0] * cb_fac;
+ rgb_to_ycbcr[4] = -coeff[1] * cb_fac;
+ rgb_to_ycbcr[7] = (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] = (1.0f - coeff[0]) * cr_fac;
+ rgb_to_ycbcr[5] = -coeff[1] * cr_fac;
+ rgb_to_ycbcr[8] = -coeff[2] * cr_fac;
+
+ // Inverting the matrix gives us what we need to go from YCbCr back to RGB.
+ Matrix3x3 ycbcr_to_rgb;
+ invert_3x3_matrix(rgb_to_ycbcr, ycbcr_to_rgb);
+
+ std::string frag_shader;
+
+ char buf[1024];
+ sprintf(buf,
+ "const mat3 PREFIX(inv_ycbcr_matrix) = mat3(\n"
+ " %.8f, %.8f, %.8f,\n"
+ " %.8f, %.8f, %.8f,\n"
+ " %.8f, %.8f, %.8f);\n",
+ ycbcr_to_rgb[0], ycbcr_to_rgb[1], ycbcr_to_rgb[2],
+ ycbcr_to_rgb[3], ycbcr_to_rgb[4], ycbcr_to_rgb[5],
+ ycbcr_to_rgb[6], ycbcr_to_rgb[7], ycbcr_to_rgb[8]);
+ frag_shader = buf;
+
+ 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;
+
+ // 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
+ //
+ // Obviously, the chroma plane here needs to be moved to the left,
+ // which means _adding_ 0.5 to the texture coordinates when sampling
+ // chroma.
+ float chroma_offset_x = (0.5f - ycbcr_format.chroma_x_position) / widths[1];
+ float chroma_offset_y = (0.5f - ycbcr_format.chroma_y_position) / heights[1];
+ sprintf(buf, "const vec2 PREFIX(chroma_offset) = vec2(%.8f, %.8f);\n",
+ chroma_offset_x, chroma_offset_y);
+ frag_shader += buf;
+
+ frag_shader += read_file("ycbcr_input.frag");
+ return frag_shader;
+}
--- /dev/null
+uniform sampler2D PREFIX(tex_y);
+uniform sampler2D PREFIX(tex_cb);
+uniform sampler2D PREFIX(tex_cr);
+
+vec4 FUNCNAME(vec2 tc) {
+ // OpenGL's origin is bottom-left, but most graphics software assumes
+ // a top-left origin. Thus, for inputs that come from the user,
+ // we flip the y coordinate.
+ tc.y = 1.0 - tc.y;
+
+ vec3 ycbcr;
+ ycbcr.x = texture2D(PREFIX(tex_y), tc).x;
+ ycbcr.y = texture2D(PREFIX(tex_cb), tc + PREFIX(chroma_offset)).x;
+ ycbcr.z = texture2D(PREFIX(tex_cr), tc + PREFIX(chroma_offset)).x;
+
+ ycbcr -= PREFIX(offset);
+ ycbcr *= PREFIX(scale);
+
+ vec4 rgba;
+ rgba.rgb = PREFIX(inv_ycbcr_matrix) * ycbcr;
+ rgba.a = 1.0;
+ return rgba;
+}
--- /dev/null
+#ifndef _YCBCR_INPUT_H
+#define _YCBCR_INPUT_H 1
+
+// YCbCrInput is for handling planar 8-bit Y'CbCr (also sometimes, usually rather
+// imprecisely, called “YUV”), which is typically what you get from a video decoder.
+// It upsamples planes as needed, using the default linear upsampling OpenGL gives you.
+
+#include "input.h"
+
+struct YCbCrFormat {
+ // Which formula for Y' to use.
+ YCbCrLumaCoefficients luma_coefficients;
+
+ // If true, assume Y'CbCr coefficients are full-range, ie. go from 0 to 255
+ // instead of the limited 220/225 steps in classic MPEG. For instance,
+ // JPEG uses the Rec. 601 luma coefficients, but full range.
+ bool full_range;
+
+ // Sampling factors for chroma components. For no subsampling (4:4:4),
+ // set both to 1.
+ unsigned chroma_subsampling_x, chroma_subsampling_y;
+
+ // Positioning of the chroma samples. MPEG-1 and JPEG is (0.5, 0.5);
+ // MPEG-2 and newer typically are (0.0, 0.5).
+ float chroma_x_position, chroma_y_position;
+};
+
+class YCbCrInput : public Input {
+public:
+ YCbCrInput(const ImageFormat &image_format,
+ const YCbCrFormat &ycbcr_format,
+ unsigned width, unsigned height);
+
+ // Create the texture itself. We cannot do this in the constructor,
+ // because we don't necessarily know all the settings (sRGB texture,
+ // mipmap generation) at that point.
+ void finalize();
+
+ virtual bool can_output_linear_gamma() const { return false; }
+
+ std::string output_fragment_shader();
+
+ // Uploads the texture if it has changed since last time.
+ void set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num);
+
+ ColorSpace get_color_space() const { return image_format.color_space; }
+ GammaCurve get_gamma_curve() const { return image_format.gamma_curve; }
+
+ // Tells the input where to fetch the actual pixel data. Note that if you change
+ // this data, you must either call set_pixel_data() again (using the same pointer
+ // is fine), or invalidate_pixel_data(). Otherwise, the texture won't be re-uploaded
+ // on subsequent frames.
+ void set_pixel_data(unsigned channel, const unsigned char *pixel_data)
+ {
+ assert(channel >= 0 && channel < 3);
+ this->pixel_data[channel] = pixel_data;
+ invalidate_pixel_data();
+ }
+
+ void invalidate_pixel_data()
+ {
+ needs_update = true;
+ }
+
+ const unsigned char *get_pixel_data(unsigned channel) const
+ {
+ assert(channel >= 0 && channel < 3);
+ return pixel_data[channel];
+ }
+
+ void set_pitch(unsigned channel, unsigned pitch) {
+ assert(!finalized);
+ assert(channel >= 0 && channel < 3);
+ this->pitch[channel] = pitch;
+ }
+
+ unsigned get_pitch(unsigned channel) {
+ assert(channel >= 0 && channel < 3);
+ return pitch[channel];
+ }
+
+private:
+ ImageFormat image_format;
+ YCbCrFormat ycbcr_format;
+ GLuint pbos[3], texture_num[3];
+ bool needs_update, finalized;
+
+ int needs_mipmaps;
+
+ unsigned width, height, widths[3], heights[3];
+ const unsigned char *pixel_data[3];
+ unsigned pitch[3];
+};
+
+#endif // !defined(_YCBCR_INPUT_H)
projects / movit / commitdiff