-uniform sampler2D PREFIX(tex_y);
-uniform sampler2D PREFIX(tex_cb);
-uniform sampler2D PREFIX(tex_cr);
+// Implicit uniforms:
+// uniform sampler2D PREFIX(tex_y);
+// uniform sampler2D PREFIX(tex_cbcr); // If CB_CR_SAME_TEXTURE.
+// uniform sampler2D PREFIX(tex_cb); // If not CB_CR_SAME_TEXTURE.
+// uniform sampler2D PREFIX(tex_cr); // If not CB_CR_SAME_TEXTURE.
+// uniform mat3 PREFIX(ycbcr_matrix);
+// uniform vec3 PREFIX(offset);
+// uniform vec2 PREFIX(cb_offset);
+// uniform vec2 PREFIX(cr_offset);