-static const double ycgco_matrix[3][3] =
-{
- { 0.25, 0.5, 0.25 },
- { -0.25, 0.5, -0.25 },
- { 0.5, 0, -0.5 },
-};
-
-static const double gbr_matrix[3][3] =
-{
- { 0, 1, 0 },
- { 0, -0.5, 0.5 },
- { 0.5, -0.5, 0 },
-};
-
-/*
- * All constants explained in e.g. https://linuxtv.org/downloads/v4l-dvb-apis/ch02s06.html
- * The older ones (bt470bg/m) are also explained in their respective ITU docs
- * (e.g. https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.470-5-199802-S!!PDF-E.pdf)
- * whereas the newer ones can typically be copied directly from wikipedia :)
- */
-static const struct LumaCoefficients luma_coefficients[AVCOL_SPC_NB] = {
- [AVCOL_SPC_FCC] = { 0.30, 0.59, 0.11 },
- [AVCOL_SPC_BT470BG] = { 0.299, 0.587, 0.114 },
- [AVCOL_SPC_SMPTE170M] = { 0.299, 0.587, 0.114 },
- [AVCOL_SPC_BT709] = { 0.2126, 0.7152, 0.0722 },
- [AVCOL_SPC_SMPTE240M] = { 0.212, 0.701, 0.087 },
- [AVCOL_SPC_YCOCG] = { 0.25, 0.5, 0.25 },
- [AVCOL_SPC_RGB] = { 1, 1, 1 },
- [AVCOL_SPC_BT2020_NCL] = { 0.2627, 0.6780, 0.0593 },
- [AVCOL_SPC_BT2020_CL] = { 0.2627, 0.6780, 0.0593 },
-};
-
-static const struct LumaCoefficients *get_luma_coefficients(enum AVColorSpace csp)
-{
- const struct LumaCoefficients *coeffs;
-
- if (csp >= AVCOL_SPC_NB)
- return NULL;
- coeffs = &luma_coefficients[csp];
- if (!coeffs->cr)
- return NULL;
-
- return coeffs;
-}
-
-static void fill_rgb2yuv_table(const struct LumaCoefficients *coeffs,
- double rgb2yuv[3][3])
-{
- double bscale, rscale;
-
- // special ycgco matrix
- if (coeffs->cr == 0.25 && coeffs->cg == 0.5 && coeffs->cb == 0.25) {
- memcpy(rgb2yuv, ycgco_matrix, sizeof(double) * 9);
- return;
- } else if (coeffs->cr == 1 && coeffs->cg == 1 && coeffs->cb == 1) {
- memcpy(rgb2yuv, gbr_matrix, sizeof(double) * 9);
- return;
- }
-
- rgb2yuv[0][0] = coeffs->cr;
- rgb2yuv[0][1] = coeffs->cg;
- rgb2yuv[0][2] = coeffs->cb;
- bscale = 0.5 / (coeffs->cb - 1.0);
- rscale = 0.5 / (coeffs->cr - 1.0);
- rgb2yuv[1][0] = bscale * coeffs->cr;
- rgb2yuv[1][1] = bscale * coeffs->cg;
- rgb2yuv[1][2] = 0.5;
- rgb2yuv[2][0] = 0.5;
- rgb2yuv[2][1] = rscale * coeffs->cg;
- rgb2yuv[2][2] = rscale * coeffs->cb;
-}
-