avfilter/vf_v360: add initial barrel split format input support

1 files changed, 128 insertions, 20 deletions

diff --git a/libavfilter/vf_v360.c b/libavfilter/vf_v360.c
index 1dae2a3e4c..eedf4fe8b2 100644
--- a/libavfilter/vf_v360.c
+++ b/libavfilter/vf_v360.c
@@ -76,6 +76,7 @@ static const AVOption v360_options[] = {
     {   "fisheye", "fisheye",                                    0, AV_OPT_TYPE_CONST,  {.i64=FISHEYE},         0,                   0, FLAGS, "in" },
     {"cylindrical", "cylindrical",                               0, AV_OPT_TYPE_CONST,  {.i64=CYLINDRICAL},     0,                   0, FLAGS, "in" },
     {"tetrahedron", "tetrahedron",                               0, AV_OPT_TYPE_CONST,  {.i64=TETRAHEDRON},     0,                   0, FLAGS, "in" },
+    {"barrelsplit", "barrel split facebook's 360 format",        0, AV_OPT_TYPE_CONST,  {.i64=BARREL_SPLIT},    0,                   0, FLAGS, "in" },
     {    "output", "set output projection",            OFFSET(out), AV_OPT_TYPE_INT,    {.i64=CUBEMAP_3_2},     0,    NB_PROJECTIONS-1, FLAGS, "out" },
     {         "e", "equirectangular",                            0, AV_OPT_TYPE_CONST,  {.i64=EQUIRECTANGULAR}, 0,                   0, FLAGS, "out" },
     {  "equirect", "equirectangular",                            0, AV_OPT_TYPE_CONST,  {.i64=EQUIRECTANGULAR}, 0,                   0, FLAGS, "out" },
@@ -2892,7 +2893,7 @@ static int barrel_to_xyz(const V360Context *s,
         float uf, vf;
 
         if (j < eh) {   // UP
-            uf = 2.f * (i - 4 * ew) / ew  - 1.f;
+            uf = 2.f * (i - 4 * ew) / ew - 1.f;
             vf = 2.f * (j         ) / eh - 1.f;
 
             uf /= scale;
@@ -2999,6 +3000,105 @@ static int xyz_to_barrel(const V360Context *s,
 }
 
 /**
+ * Calculate frame position in barrel split facebook's format for corresponding 3D coordinates on sphere.
+ *
+ * @param s filter private context
+ * @param vec coordinates on sphere
+ * @param width frame width
+ * @param height frame height
+ * @param us horizontal coordinates for interpolation window
+ * @param vs vertical coordinates for interpolation window
+ * @param du horizontal relative coordinate
+ * @param dv vertical relative coordinate
+ */
+static int xyz_to_barrelsplit(const V360Context *s,
+                              const float *vec, int width, int height,
+                              int16_t us[4][4], int16_t vs[4][4], float *du, float *dv)
+{
+    const float phi   = atan2f(vec[0], -vec[2]) * s->input_mirror_modifier[0];
+    const float theta = asinf(-vec[1]) * s->input_mirror_modifier[1];
+
+    const float theta_range = M_PI_4;
+
+    int ew, eh;
+    int u_shift, v_shift;
+    float uf, vf;
+    int ui, vi;
+
+    if (theta >= -theta_range && theta <= theta_range) {
+        const float scalew = s->fin_pad > 0 ? 1.f - s->fin_pad / (width * 2.f / 3.f) : 1.f - s->in_pad;
+        const float scaleh = s->fin_pad > 0 ? 1.f - s->fin_pad / (height / 2.f) : 1.f - s->in_pad;
+
+        ew = width / 3 * 2;
+        eh = height / 2;
+
+        u_shift = s->ih_flip ? width / 3 : 0;
+        v_shift = phi >= M_PI_2 || phi < -M_PI_2 ? eh : 0;
+
+        uf = fmodf(phi, M_PI_2) / M_PI_2;
+        vf = theta / M_PI_4;
+
+        if (v_shift)
+            uf = uf >= 0.f ? fmodf(uf - 1.f, 1.f) : fmodf(uf + 1.f, 1.f);
+
+        uf = (uf * scalew + 1.f) * width  / 3.f;
+        vf = (vf * scaleh + 1.f) * height / 4.f;
+    } else {
+        const float scalew = s->fin_pad > 0 ? 1.f - s->fin_pad / (width  / 3.f) : 1.f - s->in_pad;
+        const float scaleh = s->fin_pad > 0 ? 1.f - s->fin_pad / (height / 4.f) : 1.f - s->in_pad;
+        int v_offset = 0;
+
+        ew = width  / 3;
+        eh = height / 4;
+
+        u_shift = s->ih_flip ? 0 : 2 * ew;
+
+        if (theta <= 0.f && theta >= -M_PI_2 &&
+            phi <= M_PI_2 && phi >= -M_PI_2) {
+            uf =  vec[0] / vec[1];
+            vf = -vec[2] / vec[1];
+            v_shift = 0;
+            v_offset = -eh;
+        } else if (theta >= 0.f && theta <= M_PI_2 &&
+                   phi <= M_PI_2 && phi >= -M_PI_2) {
+            uf = -vec[0] / vec[1];
+            vf = -vec[2] / vec[1];
+            v_shift = height * 0.25f;
+        } else if (theta <= 0.f && theta >= -M_PI_2) {
+            uf = -vec[0] / vec[1];
+            vf =  vec[2] / vec[1];
+            v_shift = height * 0.5f;
+            v_offset = -eh;
+        } else {
+            uf = vec[0] / vec[1];
+            vf = vec[2] / vec[1];
+            v_shift = height * 0.75f;
+        }
+
+        uf *= s->input_mirror_modifier[0] * s->input_mirror_modifier[1];
+        vf *= s->input_mirror_modifier[1];
+
+        uf = 0.5f * width / 3.f * (uf * scalew + 1.f);
+        vf = height * 0.25f * (vf * scaleh + 1.f) + v_offset;
+    }
+
+    ui = floorf(uf);
+    vi = floorf(vf);
+
+    *du = uf - ui;
+    *dv = vf - vi;
+
+    for (int i = -1; i < 3; i++) {
+        for (int j = -1; j < 3; j++) {
+            us[i + 1][j + 1] = u_shift + av_clip(ui + j, 0, ew - 1);
+            vs[i + 1][j + 1] = v_shift + av_clip(vi + i, 0, eh - 1);
+        }
+    }
+
+    return 1;
+}
+
+/**
  * Calculate 3D coordinates on sphere for corresponding frame position in barrel split facebook's format.
  *
  * @param s filter private context
@@ -3012,16 +3112,18 @@ static int barrelsplit_to_xyz(const V360Context *s,
                               int i, int j, int width, int height,
                               float *vec)
 {
-    const float scale = 1.01f;
     const float x = (i + 0.5f) / width;
     const float y = (j + 0.5f) / height;
     float l_x, l_y, l_z;
 
-    if (x <= 2.f / 3.f) {
+    if (x < 2.f / 3.f) {
+        const float scalew = s->fout_pad > 0 ? 1.f - s->fout_pad / (width * 2.f / 3.f) : 1.f - s->out_pad;
+        const float scaleh = s->fout_pad > 0 ? 1.f - s->fout_pad / (height / 2.f) : 1.f - s->out_pad;
+
         const float back = floorf(y * 2.f);
 
-        const float phi   = ((3.f / 2.f * x - 0.5f) * scale - back + 1.f) * M_PI;
-        const float theta = (y - 0.25f - 0.5f * back) * scale * M_PI;
+        const float phi   = ((3.f / 2.f * x - 0.5f) / scalew - back + 1.f) * M_PI;
+        const float theta = (y - 0.25f - 0.5f * back) / scaleh * M_PI;
 
         const float sin_phi   = sinf(phi);
         const float cos_phi   = cosf(phi);
@@ -3032,46 +3134,47 @@ static int barrelsplit_to_xyz(const V360Context *s,
         l_y = -sin_theta;
         l_z =  cos_theta * cos_phi;
     } else {
+        const float scalew = s->fout_pad > 0 ? 1.f - s->fout_pad / (width  / 3.f) : 1.f - s->out_pad;
+        const float scaleh = s->fout_pad > 0 ? 1.f - s->fout_pad / (height / 4.f) : 1.f - s->out_pad;
+
         const int face = floorf(y * 4.f);
         float uf, vf;
 
         uf = x * 3.f - 2.f;
-        uf = (uf - 0.5f) * scale + 0.5f;
 
         switch (face) {
         case 0:
             vf = y * 2.f;
             uf = 1.f - uf;
-            vf = (0.5f - vf) * scale;
+            vf = 0.5f - vf;
 
-            l_x =  0.5f - uf;
+            l_x = (0.5f - uf) / scalew;
             l_y =  0.5f;
-            l_z = -0.5f + vf;
+            l_z = (-0.5f + vf) / scaleh;
             break;
         case 1:
             vf = y * 2.f;
             uf = 1.f - uf;
-            vf = 1.f - (vf - 0.5f) * scale;
+            vf = 1.f - (vf - 0.5f);
 
-            l_x =  0.5f - uf;
+            l_x = (0.5f - uf) / scalew;
             l_y = -0.5f;
-            l_z =  0.5f - vf;
+            l_z = (0.5f - vf) / scaleh;
             break;
         case 2:
             vf = y * 2.f - 0.5f;
-            vf = 1.f - (1.f - vf) * scale;
+            vf = 1.f - (1.f - vf);
 
-            l_x =  0.5f - uf;
-            l_y =  0.5f;
-            l_z = -0.5f + vf;
+            l_x = (0.5f - uf) / scalew;
+            l_y = 0.5f;
+            l_z = (-0.5f + vf) / scaleh;
             break;
         case 3:
             vf = y * 2.f - 1.5f;
-            vf = vf * scale;
 
-            l_x =  0.5f - uf;
+            l_x = (0.5f - uf) / scalew;
             l_y = -0.5f;
-            l_z =  0.5f - vf;
+            l_z = (0.5f - vf) / scaleh;
             break;
         }
     }
@@ -3456,7 +3559,6 @@ static int config_output(AVFilterLink *outlink)
         wf = w;
         hf = h;
         break;
-    case BARREL_SPLIT:
     case PERSPECTIVE:
     case PANNINI:
         av_log(ctx, AV_LOG_ERROR, "Supplied format is not accepted as input.\n");
@@ -3521,6 +3623,12 @@ static int config_output(AVFilterLink *outlink)
         wf = w;
         hf = h;
         break;
+    case BARREL_SPLIT:
+        s->in_transform = xyz_to_barrelsplit;
+        err = 0;
+        wf = w * 4.f / 3.f;
+        hf = h;
+        break;
     default:
         av_log(ctx, AV_LOG_ERROR, "Specified input format is not handled.\n");
         return AVERROR_BUG;