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avfilter/vf_v360: add facebook's format

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Eugene Lyapustin 2019-08-18 20:26:36 +03:00 committed by Paul B Mahol
parent 95780f4dcb
commit 20a12448aa
2 changed files with 165 additions and 0 deletions
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3
doc/filters.texi
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@ -18024,6 +18024,9 @@ No padding.
Default value is @b{@samp{0}}.
@end table
@item fb
Facebook's 360 format.
@end table
@item interp

162
libavfilter/vf_v360.c
View File

@ -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" },
@ -1646,6 +1649,153 @@ 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.
*/
@ -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;