Fix color

src/decoders/gl_render.c

@@ -17,17 +17,19 @@ static const char *fragment_shader_string = "\
 uniform lowp sampler2D ymap;\n\
 uniform lowp sampler2D umap;\n\
 uniform lowp sampler2D vmap;\n\
+uniform mat3 yuvmat;\n\
+uniform vec3 offset;\n\
 in mediump vec2 tex_position;\n\
 out vec4 FragColor;\n\
 \
 void main() {\n\
-    mediump float y = texture(ymap, tex_position).r;\n\
-    mediump float u = texture(umap, tex_position).r - 0.5;\n\
-    mediump float v = texture(vmap, tex_position).r - 0.5;\n\
-    lowp float r = y + 1.28033 * v;\n\
-    lowp float g = y - 0.21482 * u - 0.38059 * v;\n\
-    lowp float b = y + 2.12798 * u;\n\
-    FragColor = vec4(r, g, b, 1.0);\n\
+    vec3 YCbCr = vec3(\n\
+        texture(ymap, tex_position).r,\n\
+        texture(umap, tex_position).r - 0.0,\n\
+        texture(vmap, tex_position).r - 0.0\n\
+    );\n\
+    YCbCr -= offset;\n\
+    FragColor = vec4(clamp(yuvmat * YCbCr, 0.0, 1.0), 1.0);\n\
 }";
 
 static const float vertices[] = {
@@ -42,6 +44,7 @@ static GLuint texture_id[3], texture_uniform[3];
 static GLuint shader_program;
 static GLuint vbo, vao;
 static int gl_render_width = 0, gl_render_height = 0;
+static int yuvmat_location, offset_location;
 
 void gl_render_init() {
     shader_program = glCreateProgram();
@@ -73,9 +76,12 @@ void gl_render_init() {
     
     glUseProgram(shader_program);
     
-    int position = glGetAttribLocation(shader_program, "position");
-    glEnableVertexAttribArray(position);
+    int position_location = glGetAttribLocation(shader_program, "position");
+    glEnableVertexAttribArray(position_location);
     glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, NULL);
+    
+    yuvmat_location = glGetUniformLocation(shader_program, "yuvmat");
+    offset_location = glGetUniformLocation(shader_program, "offset");
 }
 
 void gl_render_setup(int width, int height) {
@@ -98,12 +104,67 @@ void gl_render_setup(int width, int height) {
     }
 }
 
-void gl_render_draw(uint8_t* image[3]) {
+const float* gl_color_offset(bool color_full) {
+    static const float limitedOffsets[] = { 16.0f / 255.0f, 128.0f / 255.0f, 128.0f / 255.0f };
+    static const float fullOffsets[] = { 0.0f, 128.0f / 255.0f, 128.0f / 255.0f };
+    return color_full ? fullOffsets : limitedOffsets;
+}
+
+const float* gl_color_matrix(enum AVColorSpace color_space, bool color_full) {
+    static const float bt601Lim[] = {
+        1.1644f, 1.1644f, 1.1644f,
+        0.0f, -0.3917f, 2.0172f,
+        1.5960f, -0.8129f, 0.0f
+    };
+    static const float bt601Full[] = {
+        1.0f, 1.0f, 1.0f,
+        0.0f, -0.3441f, 1.7720f,
+        1.4020f, -0.7141f, 0.0f
+    };
+    static const float bt709Lim[] = {
+        1.1644f, 1.1644f, 1.1644f,
+        0.0f, -0.2132f, 2.1124f,
+        1.7927f, -0.5329f, 0.0f
+    };
+    static const float bt709Full[] = {
+        1.0f, 1.0f, 1.0f,
+        0.0f, -0.1873f, 1.8556f,
+        1.5748f, -0.4681f, 0.0f
+    };
+    static const float bt2020Lim[] = {
+        1.1644f, 1.1644f, 1.1644f,
+        0.0f, -0.1874f, 2.1418f,
+        1.6781f, -0.6505f, 0.0f
+    };
+    static const float bt2020Full[] = {
+        1.0f, 1.0f, 1.0f,
+        0.0f, -0.1646f, 1.8814f,
+        1.4746f, -0.5714f, 0.0f
+    };
+    
+    switch (color_space) {
+        case AVCOL_SPC_SMPTE170M:
+        case AVCOL_SPC_BT470BG:
+            return color_full ? bt601Full : bt601Lim;
+        case AVCOL_SPC_BT709:
+            return color_full ? bt709Full : bt709Lim;
+        case AVCOL_SPC_BT2020_NCL:
+        case AVCOL_SPC_BT2020_CL:
+            return color_full ? bt2020Full : bt2020Lim;
+        default:
+            return bt601Lim;
+    };
+}
+
+void gl_render_draw(uint8_t* image[3], enum AVColorSpace color_space, enum AVColorRange color_range) {
     glClearColor(0, 0, 0, 1);
     glClear(GL_COLOR_BUFFER_BIT);
     
     glUseProgram(shader_program);
     
+    glUniform3fv(offset_location, 1, gl_color_offset(color_range == AVCOL_RANGE_JPEG));
+    glUniformMatrix3fv(yuvmat_location, 1, GL_FALSE, gl_color_matrix(color_space, color_range == AVCOL_RANGE_JPEG));
+    
     for (int i = 0; i < 3; i++) {
         glActiveTexture(GL_TEXTURE0 + i);
         glBindTexture(GL_TEXTURE_2D, texture_id[i]);

src/decoders/gl_render.h

@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdint.h>
+#include <libavcodec/avcodec.h>
 
 #ifdef __cplusplus
 #define EXTERN extern "C"
@@ -9,4 +10,4 @@
 
 EXTERN void gl_render_init();
 EXTERN void gl_render_setup(int width, int height);
-EXTERN void gl_render_draw(uint8_t* image[3]);
+EXTERN void gl_render_draw(uint8_t* image[3], enum AVColorSpace color_space, enum AVColorRange color_range);

src/ui/windows/StreamWindow.cpp

@@ -106,7 +106,7 @@ void StreamWindow::draw(NVGcontext *ctx) {
     gl_render_setup(m_config.width, m_config.height);
     
     if (frame != NULL) {
-        gl_render_draw(frame->data);
+        gl_render_draw(frame->data, frame->colorspace, frame->color_range);
     }
     
     nvgRestore(ctx);