avutil/csp: create public API for colorspace structs

This commit moves some of the functionality from avfilter/colorspace
into avutil/csp and exposes it as a public API so it can be used by
libavcodec and/or libavformat. It also converts those structs from
double values to AVRational to make regression testing easier and
more consistent.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>

1 files changed, 30 insertions, 113 deletions

diff --git a/libavfilter/colorspace.c b/libavfilter/colorspace.c
index 8d7b882375..7f74fe5113 100644
--- a/libavfilter/colorspace.c
+++ b/libavfilter/colorspace.c
@@ -65,24 +65,28 @@ void ff_matrix_mul_3x3(double dst[3][3],
 /*
  * see e.g. http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
  */
-void ff_fill_rgb2xyz_table(const struct PrimaryCoefficients *coeffs,
-                           const struct WhitepointCoefficients *wp,
+void ff_fill_rgb2xyz_table(const AVPrimaryCoefficients *coeffs,
+                           const AVWhitepointCoefficients *wp,
                            double rgb2xyz[3][3])
 {
     double i[3][3], sr, sg, sb, zw;
-
-    rgb2xyz[0][0] = coeffs->xr / coeffs->yr;
-    rgb2xyz[0][1] = coeffs->xg / coeffs->yg;
-    rgb2xyz[0][2] = coeffs->xb / coeffs->yb;
+    double xr = av_q2d(coeffs->r.x), yr = av_q2d(coeffs->r.y);
+    double xg = av_q2d(coeffs->g.x), yg = av_q2d(coeffs->g.y);
+    double xb = av_q2d(coeffs->b.x), yb = av_q2d(coeffs->b.y);
+    double xw = av_q2d(wp->x), yw = av_q2d(wp->y);
+
+    rgb2xyz[0][0] = xr / yr;
+    rgb2xyz[0][1] = xg / yg;
+    rgb2xyz[0][2] = xb / yb;
     rgb2xyz[1][0] = rgb2xyz[1][1] = rgb2xyz[1][2] = 1.0;
-    rgb2xyz[2][0] = (1.0 - coeffs->xr - coeffs->yr) / coeffs->yr;
-    rgb2xyz[2][1] = (1.0 - coeffs->xg - coeffs->yg) / coeffs->yg;
-    rgb2xyz[2][2] = (1.0 - coeffs->xb - coeffs->yb) / coeffs->yb;
+    rgb2xyz[2][0] = (1.0 - xr - yr) / yr;
+    rgb2xyz[2][1] = (1.0 - xg - yg) / yg;
+    rgb2xyz[2][2] = (1.0 - xb - yb) / yb;
     ff_matrix_invert_3x3(rgb2xyz, i);
-    zw = 1.0 - wp->xw - wp->yw;
-    sr = i[0][0] * wp->xw + i[0][1] * wp->yw + i[0][2] * zw;
-    sg = i[1][0] * wp->xw + i[1][1] * wp->yw + i[1][2] * zw;
-    sb = i[2][0] * wp->xw + i[2][1] * wp->yw + i[2][2] * zw;
+    zw = 1.0 - xw - yw;
+    sr = i[0][0] * xw + i[0][1] * yw + i[0][2] * zw;
+    sg = i[1][0] * xw + i[1][1] * yw + i[1][2] * zw;
+    sb = i[2][0] * xw + i[2][1] * yw + i[2][2] * zw;
     rgb2xyz[0][0] *= sr;
     rgb2xyz[0][1] *= sg;
     rgb2xyz[0][2] *= sb;
@@ -107,119 +111,32 @@ static const double gbr_matrix[3][3] =
     { 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 },
-};
-
-const struct LumaCoefficients *ff_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;
-}
-
-#define WP_D65 { 0.3127, 0.3290 }
-#define WP_C   { 0.3100, 0.3160 }
-#define WP_DCI { 0.3140, 0.3510 }
-#define WP_E   { 1/3.0f, 1/3.0f }
-
-static const struct ColorPrimaries color_primaries[AVCOL_PRI_NB] = {
-    [AVCOL_PRI_BT709]     = { WP_D65, { 0.640, 0.330, 0.300, 0.600, 0.150, 0.060 } },
-    [AVCOL_PRI_BT470M]    = { WP_C,   { 0.670, 0.330, 0.210, 0.710, 0.140, 0.080 } },
-    [AVCOL_PRI_BT470BG]   = { WP_D65, { 0.640, 0.330, 0.290, 0.600, 0.150, 0.060 } },
-    [AVCOL_PRI_SMPTE170M] = { WP_D65, { 0.630, 0.340, 0.310, 0.595, 0.155, 0.070 } },
-    [AVCOL_PRI_SMPTE240M] = { WP_D65, { 0.630, 0.340, 0.310, 0.595, 0.155, 0.070 } },
-    [AVCOL_PRI_SMPTE428]  = { WP_E,   { 0.735, 0.265, 0.274, 0.718, 0.167, 0.009 } },
-    [AVCOL_PRI_SMPTE431]  = { WP_DCI, { 0.680, 0.320, 0.265, 0.690, 0.150, 0.060 } },
-    [AVCOL_PRI_SMPTE432]  = { WP_D65, { 0.680, 0.320, 0.265, 0.690, 0.150, 0.060 } },
-    [AVCOL_PRI_FILM]      = { WP_C,   { 0.681, 0.319, 0.243, 0.692, 0.145, 0.049 } },
-    [AVCOL_PRI_BT2020]    = { WP_D65, { 0.708, 0.292, 0.170, 0.797, 0.131, 0.046 } },
-    [AVCOL_PRI_JEDEC_P22] = { WP_D65, { 0.630, 0.340, 0.295, 0.605, 0.155, 0.077 } },
-};
-
-const struct ColorPrimaries *ff_get_color_primaries(enum AVColorPrimaries prm)
-{
-    const struct ColorPrimaries *p;
-
-    if (prm >= AVCOL_PRI_NB)
-        return NULL;
-    p = &color_primaries[prm];
-    if (!p->prim.xr)
-        return NULL;
-
-    return p;
-}
-
-enum AVColorPrimaries ff_detect_color_primaries(const struct ColorPrimaries *prm)
-{
-    double delta;
-
-    for (enum AVColorPrimaries p = 0; p < AVCOL_PRI_NB; p++) {
-        const struct ColorPrimaries *ref = &color_primaries[p];
-        if (!ref->prim.xr)
-            continue;
-
-        delta = fabs(prm->prim.xr - ref->prim.xr) +
-                fabs(prm->prim.yr - ref->prim.yr) +
-                fabs(prm->prim.yg - ref->prim.yg) +
-                fabs(prm->prim.yg - ref->prim.yg) +
-                fabs(prm->prim.yb - ref->prim.yb) +
-                fabs(prm->prim.yb - ref->prim.yb) +
-                fabs(prm->wp.xw - ref->wp.xw) +
-                fabs(prm->wp.yw - ref->wp.yw);
-
-        if (delta < 0.001)
-            return p;
-    }
-
-    return AVCOL_PRI_UNSPECIFIED;
-}
-
-void ff_fill_rgb2yuv_table(const struct LumaCoefficients *coeffs,
+void ff_fill_rgb2yuv_table(const AVLumaCoefficients *coeffs,
                            double rgb2yuv[3][3])
 {
     double bscale, rscale;
+    double cr = av_q2d(coeffs->cr), cg = av_q2d(coeffs->cg), cb = av_q2d(coeffs->cb);
 
     // special ycgco matrix
-    if (coeffs->cr == 0.25 && coeffs->cg == 0.5 && coeffs->cb == 0.25) {
+    if (cr == 0.25 && cg == 0.5 && cb == 0.25) {
         memcpy(rgb2yuv, ycgco_matrix, sizeof(double) * 9);
         return;
-    } else if (coeffs->cr == 1 && coeffs->cg == 1 && coeffs->cb == 1) {
+    } else if (cr == 1 && cg == 1 && 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[0][0] = cr;
+    rgb2yuv[0][1] = cg;
+    rgb2yuv[0][2] = cb;
+    bscale = 0.5 / (cb - 1.0);
+    rscale = 0.5 / (cr - 1.0);
+    rgb2yuv[1][0] = bscale * cr;
+    rgb2yuv[1][1] = bscale * cg;
     rgb2yuv[1][2] = 0.5;
     rgb2yuv[2][0] = 0.5;
-    rgb2yuv[2][1] = rscale * coeffs->cg;
-    rgb2yuv[2][2] = rscale * coeffs->cb;
+    rgb2yuv[2][1] = rscale * cg;
+    rgb2yuv[2][2] = rscale * cb;
 }
 
 double ff_determine_signal_peak(AVFrame *in)