[FFmpeg-cvslog] avfilter/vf_v360: add facebook's format
Eugene Lyapustin
git at videolan.org
Fri Aug 30 12:45:10 EEST 2019
ffmpeg | branch: master | Eugene Lyapustin <unishifft at gmail.com> | Sun Aug 18 20:26:36 2019 +0300| [20a12448aaf140cf1ec06ee22e1ab4ebaea5c9ba] | committer: Paul B Mahol
avfilter/vf_v360: add facebook's format
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=20a12448aaf140cf1ec06ee22e1ab4ebaea5c9ba
---
doc/filters.texi | 3 +
libavfilter/vf_v360.c | 162 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 165 insertions(+)
diff --git a/doc/filters.texi b/doc/filters.texi
index 7759fe177b..2271749e49 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -18024,6 +18024,9 @@ No padding.
Default value is @b{@samp{0}}.
@end table
+ at item fb
+Facebook's 360 format.
+
@end table
@item interp
diff --git a/libavfilter/vf_v360.c b/libavfilter/vf_v360.c
index aad1afd129..9b7f0c109e 100644
--- a/libavfilter/vf_v360.c
+++ b/libavfilter/vf_v360.c
@@ -48,6 +48,7 @@ enum Projections {
EQUIANGULAR,
FLAT,
DUAL_FISHEYE,
+ FACEBOOK,
NB_PROJECTIONS,
};
@@ -137,12 +138,14 @@ static const AVOption v360_options[] = {
{ "c6x1", "cubemap6x1", 0, AV_OPT_TYPE_CONST, {.i64=CUBEMAP_6_1}, 0, 0, FLAGS, "in" },
{ "eac", "equi-angular", 0, AV_OPT_TYPE_CONST, {.i64=EQUIANGULAR}, 0, 0, FLAGS, "in" },
{ "dfisheye", "dual fisheye", 0, AV_OPT_TYPE_CONST, {.i64=DUAL_FISHEYE}, 0, 0, FLAGS, "in" },
+ { "fb", "facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64=FACEBOOK}, 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" },
{ "c3x2", "cubemap3x2", 0, AV_OPT_TYPE_CONST, {.i64=CUBEMAP_3_2}, 0, 0, FLAGS, "out" },
{ "c6x1", "cubemap6x1", 0, AV_OPT_TYPE_CONST, {.i64=CUBEMAP_6_1}, 0, 0, FLAGS, "out" },
{ "eac", "equi-angular", 0, AV_OPT_TYPE_CONST, {.i64=EQUIANGULAR}, 0, 0, FLAGS, "out" },
{ "flat", "regular video", 0, AV_OPT_TYPE_CONST, {.i64=FLAT}, 0, 0, FLAGS, "out" },
+ { "fb", "facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64=FACEBOOK}, 0, 0, FLAGS, "out" },
{ "interp", "set interpolation method", OFFSET(interp), AV_OPT_TYPE_INT, {.i64=BILINEAR}, 0, NB_INTERP_METHODS-1, FLAGS, "interp" },
{ "near", "nearest neighbour", 0, AV_OPT_TYPE_CONST, {.i64=NEAREST}, 0, 0, FLAGS, "interp" },
{ "nearest", "nearest neighbour", 0, AV_OPT_TYPE_CONST, {.i64=NEAREST}, 0, 0, FLAGS, "interp" },
@@ -1647,6 +1650,153 @@ static void xyz_to_dfisheye(const V360Context *s,
}
/**
+ * Calculate 3D coordinates on sphere for corresponding frame position in facebook's format.
+ *
+ * @param s filter context
+ * @param i horizontal position on frame [0, height)
+ * @param j vertical position on frame [0, width)
+ * @param width frame width
+ * @param height frame height
+ * @param vec coordinates on sphere
+ */
+static void fb_to_xyz(const V360Context *s,
+ int i, int j, int width, int height,
+ float *vec)
+{
+ const float scale = 0.99f;
+ float l_x, l_y, l_z;
+
+ if (i < 4 * width / 5) {
+ const float theta_range = M_PI / 4.f;
+
+ const int ew = 4 * width / 5;
+ const int eh = height;
+
+ const float phi = ((2.f * i) / ew - 1.f) * M_PI / scale;
+ const float theta = ((2.f * j) / eh - 1.f) * theta_range / scale;
+
+ const float sin_phi = sinf(phi);
+ const float cos_phi = cosf(phi);
+ const float sin_theta = sinf(theta);
+ const float cos_theta = cosf(theta);
+
+ l_x = cos_theta * sin_phi;
+ l_y = -sin_theta;
+ l_z = -cos_theta * cos_phi;
+ } else {
+ const int ew = width / 5;
+ const int eh = height / 2;
+
+ float uf, vf;
+ float norm;
+
+ if (j < eh) { // UP
+ uf = 2.f * (i - 4 * ew) / ew - 1.f;
+ vf = 2.f * (j ) / eh - 1.f;
+
+ uf /= scale;
+ vf /= scale;
+
+ l_x = uf;
+ l_y = 1.f;
+ l_z = -vf;
+ } else { // DOWN
+ uf = 2.f * (i - 4 * ew) / ew - 1.f;
+ vf = 2.f * (j - eh) / eh - 1.f;
+
+ uf /= scale;
+ vf /= scale;
+
+ l_x = uf;
+ l_y = -1.f;
+ l_z = vf;
+ }
+
+ norm = sqrtf(l_x * l_x + l_y * l_y + l_z * l_z);
+
+ l_x /= norm;
+ l_y /= norm;
+ l_z /= norm;
+ }
+
+ vec[0] = l_x;
+ vec[1] = l_y;
+ vec[2] = l_z;
+}
+
+/**
+ * Calculate frame position in facebook's format for corresponding 3D coordinates on sphere.
+ *
+ * @param s filter 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 void xyz_to_fb(const V360Context *s,
+ const float *vec, int width, int height,
+ uint16_t us[4][4], uint16_t vs[4][4], float *du, float *dv)
+{
+ const float scale = 0.99f;
+
+ const float phi = atan2f(vec[0], -vec[2]);
+ const float theta = asinf(-vec[1]);
+ const float theta_range = M_PI / 4.f;
+
+ int ew, eh;
+ int u_shift, v_shift;
+ float uf, vf;
+ int ui, vi;
+ int i, j;
+
+ if (theta > -theta_range && theta < theta_range) {
+ ew = 4 * width / 5;
+ eh = height;
+
+ u_shift = 0;
+ v_shift = 0;
+
+ uf = (phi / M_PI * scale + 1.f) * ew / 2.f;
+ vf = (theta / theta_range * scale + 1.f) * eh / 2.f;
+ } else {
+ ew = width / 5;
+ eh = height / 2;
+
+ u_shift = 4 * ew;
+
+ if (theta < 0.f) { // UP
+ uf = vec[0] / vec[1];
+ vf = -vec[2] / vec[1];
+ v_shift = 0;
+ } else { // DOWN
+ uf = -vec[0] / vec[1];
+ vf = -vec[2] / vec[1];
+ v_shift = eh;
+ }
+
+ uf = 0.5f * ew * (uf * scale + 1.f);
+ vf = 0.5f * eh * (vf * scale + 1.f);
+ }
+
+ ui = floorf(uf);
+ vi = floorf(vf);
+
+ *du = uf - ui;
+ *dv = vf - vi;
+
+ for (i = -1; i < 3; i++) {
+ for (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);
+ }
+ }
+
+}
+
+/**
* Calculate rotation matrix for yaw/pitch/roll angles.
*/
static inline void calculate_rotation_matrix(float yaw, float pitch, float roll,
@@ -1789,6 +1939,12 @@ static int config_output(AVFilterLink *outlink)
wf = inlink->w;
hf = inlink->h;
break;
+ case FACEBOOK:
+ in_transform = xyz_to_fb;
+ err = 0;
+ wf = inlink->w / 5.f * 4.f;
+ hf = inlink->h;
+ break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified input format is not handled.\n");
return AVERROR_BUG;
@@ -1832,6 +1988,12 @@ static int config_output(AVFilterLink *outlink)
case DUAL_FISHEYE:
av_log(ctx, AV_LOG_ERROR, "Dual fisheye format is not accepted as output.\n");
return AVERROR(EINVAL);
+ case FACEBOOK:
+ out_transform = fb_to_xyz;
+ err = 0;
+ w = roundf(wf / 4.f * 5.f);
+ h = roundf(hf);
+ break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified output format is not handled.\n");
return AVERROR_BUG;
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