Unbreak YCbCrInput (it needs to still support setting the "needs_mipmaps" int to...
[movit] / ycbcr_input.cpp
1 #include <Eigen/Core>
2 #include <Eigen/LU>
3 #include <epoxy/gl.h>
4 #include <assert.h>
5 #include <stdio.h>
6 #include <string.h>
7
8 #include "effect_util.h"
9 #include "resource_pool.h"
10 #include "util.h"
11 #include "ycbcr_input.h"
12
13 using namespace Eigen;
14 using namespace std;
15
16 namespace movit {
17
18 namespace {
19
20 // OpenGL has texel center in (0.5, 0.5), but different formats have
21 // chroma in various other places. If luma samples are X, the chroma
22 // sample is *, and subsampling is 3x3, the situation with chroma
23 // center in (0.5, 0.5) looks approximately like this:
24 //
25 //   X   X
26 //     *   
27 //   X   X
28 //
29 // If, on the other hand, chroma center is in (0.0, 0.5) (common
30 // for e.g. MPEG-4), the figure changes to:
31 //
32 //   X   X
33 //   *      
34 //   X   X
35 //
36 // In other words, (0.0, 0.0) means that the chroma sample is exactly
37 // co-sited on top of the top-left luma sample. Note, however, that
38 // this is _not_ 0.5 texels to the left, since the OpenGL's texel center
39 // is in (0.5, 0.5); it is in (0.25, 0.25). In a sense, the four luma samples
40 // define a square where chroma position (0.0, 0.0) is in texel position
41 // (0.25, 0.25) and chroma position (1.0, 1.0) is in texel position (0.75, 0.75)
42 // (the outer border shows the borders of the texel itself, ie. from
43 // (0, 0) to (1, 1)):
44 //
45 //  ---------
46 // |         |
47 // |  X---X  |
48 // |  | * |  |
49 // |  X---X  |
50 // |         |
51 //  ---------
52 //
53 // Also note that if we have no subsampling, the square will have zero
54 // area and the chroma position does not matter at all.
55 float compute_chroma_offset(float pos, unsigned subsampling_factor, unsigned resolution)
56 {
57         float local_chroma_pos = (0.5 + pos * (subsampling_factor - 1)) / subsampling_factor;
58         return (0.5 - local_chroma_pos) / resolution;
59 }
60
61 }  // namespace
62
63 YCbCrInput::YCbCrInput(const ImageFormat &image_format,
64                        const YCbCrFormat &ycbcr_format,
65                        unsigned width, unsigned height)
66         : image_format(image_format),
67           ycbcr_format(ycbcr_format),
68           width(width),
69           height(height),
70           resource_pool(NULL)
71 {
72         pbos[0] = pbos[1] = pbos[2] = 0;
73         texture_num[0] = texture_num[1] = texture_num[2] = 0;
74
75         assert(width % ycbcr_format.chroma_subsampling_x == 0);
76         pitch[0] = widths[0] = width;
77         pitch[1] = widths[1] = width / ycbcr_format.chroma_subsampling_x;
78         pitch[2] = widths[2] = width / ycbcr_format.chroma_subsampling_x;
79
80         assert(height % ycbcr_format.chroma_subsampling_y == 0);
81         heights[0] = height;
82         heights[1] = height / ycbcr_format.chroma_subsampling_y;
83         heights[2] = height / ycbcr_format.chroma_subsampling_y;
84
85         pixel_data[0] = pixel_data[1] = pixel_data[2] = NULL;
86 }
87
88 YCbCrInput::~YCbCrInput()
89 {
90         for (unsigned channel = 0; channel < 3; ++channel) {
91                 if (texture_num[channel] != 0) {
92                         resource_pool->release_2d_texture(texture_num[channel]);
93                 }
94         }
95 }
96
97 void YCbCrInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
98 {
99         for (unsigned channel = 0; channel < 3; ++channel) {
100                 glActiveTexture(GL_TEXTURE0 + *sampler_num + channel);
101                 check_error();
102
103                 if (texture_num[channel] == 0) {
104                         // (Re-)upload the texture.
105                         texture_num[channel] = resource_pool->create_2d_texture(GL_R8, widths[channel], heights[channel]);
106                         glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
107                         check_error();
108                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
109                         check_error();
110                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbos[channel]);
111                         check_error();
112                         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
113                         check_error();
114                         glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch[channel]);
115                         check_error();
116                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, widths[channel], heights[channel], GL_RED, GL_UNSIGNED_BYTE, pixel_data[channel]);
117                         check_error();
118                         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
119                         check_error();
120                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
121                         check_error();
122                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
123                         check_error();
124                 } else {
125                         glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
126                         check_error();
127                 }
128         }
129
130         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
131         check_error();
132
133         // Bind samplers.
134         set_uniform_int(glsl_program_num, prefix, "tex_y", *sampler_num + 0);
135         set_uniform_int(glsl_program_num, prefix, "tex_cb", *sampler_num + 1);
136         set_uniform_int(glsl_program_num, prefix, "tex_cr", *sampler_num + 2);
137
138         *sampler_num += 3;
139 }
140
141 string YCbCrInput::output_fragment_shader()
142 {
143         float coeff[3], offset[3];
144         double scale[3];
145
146         switch (ycbcr_format.luma_coefficients) {
147         case YCBCR_REC_601:
148                 // Rec. 601, page 2.
149                 coeff[0] = 0.299;
150                 coeff[1] = 0.587;
151                 coeff[2] = 0.114;
152                 break;
153
154         case YCBCR_REC_709:
155                 // Rec. 709, page 19.
156                 coeff[0] = 0.2126;
157                 coeff[1] = 0.7152;
158                 coeff[2] = 0.0722;
159                 break;
160
161         case YCBCR_REC_2020:
162                 // Rec. 2020, page 4.
163                 coeff[0] = 0.2627;
164                 coeff[1] = 0.6780;
165                 coeff[2] = 0.0593;
166                 break;
167
168         default:
169                 assert(false);
170         }
171
172         if (ycbcr_format.full_range) {
173                 offset[0] = 0.0 / 255.0;
174                 offset[1] = 128.0 / 255.0;
175                 offset[2] = 128.0 / 255.0;
176
177                 scale[0] = 1.0;
178                 scale[1] = 1.0;
179                 scale[2] = 1.0;
180         } else {
181                 // Rec. 601, page 4; Rec. 709, page 19; Rec. 2020, page 4.
182                 offset[0] = 16.0 / 255.0;
183                 offset[1] = 128.0 / 255.0;
184                 offset[2] = 128.0 / 255.0;
185
186                 scale[0] = 255.0 / 219.0;
187                 scale[1] = 255.0 / 224.0;
188                 scale[2] = 255.0 / 224.0;
189         }
190
191         // Matrix to convert RGB to YCbCr. See e.g. Rec. 601.
192         Matrix3d rgb_to_ycbcr;
193         rgb_to_ycbcr(0,0) = coeff[0];
194         rgb_to_ycbcr(0,1) = coeff[1];
195         rgb_to_ycbcr(0,2) = coeff[2];
196
197         float cb_fac = (224.0 / 219.0) / (coeff[0] + coeff[1] + 1.0f - coeff[2]);
198         rgb_to_ycbcr(1,0) = -coeff[0] * cb_fac;
199         rgb_to_ycbcr(1,1) = -coeff[1] * cb_fac;
200         rgb_to_ycbcr(1,2) = (1.0f - coeff[2]) * cb_fac;
201
202         float cr_fac = (224.0 / 219.0) / (1.0f - coeff[0] + coeff[1] + coeff[2]);
203         rgb_to_ycbcr(2,0) = (1.0f - coeff[0]) * cr_fac;
204         rgb_to_ycbcr(2,1) = -coeff[1] * cr_fac;
205         rgb_to_ycbcr(2,2) = -coeff[2] * cr_fac;
206
207         // Inverting the matrix gives us what we need to go from YCbCr back to RGB.
208         Matrix3d ycbcr_to_rgb = rgb_to_ycbcr.inverse();
209
210         // Fold in the scaling.
211         ycbcr_to_rgb *= Map<const Vector3d>(scale).asDiagonal();
212
213         string frag_shader;
214
215         frag_shader = output_glsl_mat3("PREFIX(inv_ycbcr_matrix)", ycbcr_to_rgb);
216         frag_shader += output_glsl_vec3("PREFIX(offset)", offset[0], offset[1], offset[2]);
217
218         float cb_offset_x = compute_chroma_offset(
219                 ycbcr_format.cb_x_position, ycbcr_format.chroma_subsampling_x, widths[1]);
220         float cb_offset_y = compute_chroma_offset(
221                 ycbcr_format.cb_y_position, ycbcr_format.chroma_subsampling_y, heights[1]);
222         frag_shader += output_glsl_vec2("PREFIX(cb_offset)", cb_offset_x, cb_offset_y);
223
224         float cr_offset_x = compute_chroma_offset(
225                 ycbcr_format.cr_x_position, ycbcr_format.chroma_subsampling_x, widths[2]);
226         float cr_offset_y = compute_chroma_offset(
227                 ycbcr_format.cr_y_position, ycbcr_format.chroma_subsampling_y, heights[2]);
228         frag_shader += output_glsl_vec2("PREFIX(cr_offset)", cr_offset_x, cr_offset_y);
229
230         frag_shader += read_file("ycbcr_input.frag");
231         return frag_shader;
232 }
233
234 void YCbCrInput::invalidate_pixel_data()
235 {
236         for (unsigned channel = 0; channel < 3; ++channel) {
237                 if (texture_num[channel] != 0) {
238                         resource_pool->release_2d_texture(texture_num[channel]);
239                         texture_num[channel] = 0;
240                 }
241         }
242 }
243
244 bool YCbCrInput::set_int(const std::string& key, int value)
245 {
246         if (key == "needs_mipmaps") {
247                 // We currently do not support this.
248                 return (value == 0);
249         }
250         return Effect::set_int(key, value);
251 }
252
253 }  // namespace movit