+ switch (_pixel_format) {
+ case AV_PIX_FMT_RGB24:
+ {
+ /* Going onto RGB24. First byte is red, second green, third blue */
+ int const this_bpp = 3;
+ for (int ty = start_ty, oy = start_oy; ty < size().height && oy < other->size().height; ++ty, ++oy) {
+ uint8_t* tp = data()[0] + ty * stride()[0] + start_tx * this_bpp;
+ uint8_t* op = other->data()[0] + oy * other->stride()[0];
+ for (int tx = start_tx, ox = start_ox; tx < size().width && ox < other->size().width; ++tx, ++ox) {
+ float const alpha = float (op[3]) / 255;
+ tp[0] = op[2] * alpha + tp[0] * (1 - alpha);
+ tp[1] = op[1] * alpha + tp[1] * (1 - alpha);
+ tp[2] = op[0] * alpha + tp[2] * (1 - alpha);
+
+ tp += this_bpp;
+ op += other_bpp;
+ }
+ }
+ break;
+ }
+ case AV_PIX_FMT_BGRA:
+ case AV_PIX_FMT_RGBA:
+ {
+ int const this_bpp = 4;
+ for (int ty = start_ty, oy = start_oy; ty < size().height && oy < other->size().height; ++ty, ++oy) {
+ uint8_t* tp = data()[0] + ty * stride()[0] + start_tx * this_bpp;
+ uint8_t* op = other->data()[0] + oy * other->stride()[0];
+ for (int tx = start_tx, ox = start_ox; tx < size().width && ox < other->size().width; ++tx, ++ox) {
+ float const alpha = float (op[3]) / 255;
+ tp[0] = op[0] * alpha + tp[0] * (1 - alpha);
+ tp[1] = op[1] * alpha + tp[1] * (1 - alpha);
+ tp[2] = op[2] * alpha + tp[2] * (1 - alpha);
+ tp[3] = op[3] * alpha + tp[3] * (1 - alpha);
+
+ tp += this_bpp;
+ op += other_bpp;
+ }
+ }
+ break;
+ }
+ case AV_PIX_FMT_RGB48LE:
+ {
+ int const this_bpp = 6;
+ for (int ty = start_ty, oy = start_oy; ty < size().height && oy < other->size().height; ++ty, ++oy) {
+ uint8_t* tp = data()[0] + ty * stride()[0] + start_tx * this_bpp;
+ uint8_t* op = other->data()[0] + oy * other->stride()[0];
+ for (int tx = start_tx, ox = start_ox; tx < size().width && ox < other->size().width; ++tx, ++ox) {
+ float const alpha = float (op[3]) / 255;
+ /* Blend high bytes; the RGBA in op appears to be BGRA */
+ tp[1] = op[2] * alpha + tp[1] * (1 - alpha);
+ tp[3] = op[1] * alpha + tp[3] * (1 - alpha);
+ tp[5] = op[0] * alpha + tp[5] * (1 - alpha);
+
+ tp += this_bpp;
+ op += other_bpp;
+ }
+ }
+ break;
+ }
+ case AV_PIX_FMT_XYZ12LE:
+ {
+ dcp::ColourConversion conv = dcp::ColourConversion::srgb_to_xyz();
+ double fast_matrix[9];
+ dcp::combined_rgb_to_xyz (conv, fast_matrix);
+ double const * lut_in = conv.in()->lut (8, false);
+ double const * lut_out = conv.out()->lut (16, true);
+ int const this_bpp = 6;
+ for (int ty = start_ty, oy = start_oy; ty < size().height && oy < other->size().height; ++ty, ++oy) {
+ uint16_t* tp = reinterpret_cast<uint16_t*> (data()[0] + ty * stride()[0] + start_tx * this_bpp);
+ uint8_t* op = other->data()[0] + oy * other->stride()[0];
+ for (int tx = start_tx, ox = start_ox; tx < size().width && ox < other->size().width; ++tx, ++ox) {
+ float const alpha = float (op[3]) / 255;
+
+ /* Convert sRGB to XYZ; op is BGRA. First, input gamma LUT */
+ double const r = lut_in[op[2]];
+ double const g = lut_in[op[1]];
+ double const b = lut_in[op[0]];
+
+ /* RGB to XYZ, including Bradford transform and DCI companding */
+ double const x = max (0.0, min (65535.0, r * fast_matrix[0] + g * fast_matrix[1] + b * fast_matrix[2]));
+ double const y = max (0.0, min (65535.0, r * fast_matrix[3] + g * fast_matrix[4] + b * fast_matrix[5]));
+ double const z = max (0.0, min (65535.0, r * fast_matrix[6] + g * fast_matrix[7] + b * fast_matrix[8]));
+
+ /* Out gamma LUT and blend */
+ tp[0] = lrint(lut_out[lrint(x)] * 65535) * alpha + tp[0] * (1 - alpha);
+ tp[1] = lrint(lut_out[lrint(y)] * 65535) * alpha + tp[1] * (1 - alpha);
+ tp[2] = lrint(lut_out[lrint(z)] * 65535) * alpha + tp[2] * (1 - alpha);
+
+ tp += this_bpp / 2;
+ op += other_bpp;
+ }