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avfilter/vf_v360: add truncated square pyramid input format

This commit is contained in:
Paul B Mahol 2020-03-02 19:05:13 +01:00
parent 3dd81be866
commit 6e1913a02e
2 changed files with 78 additions and 1 deletions
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2
doc/filters.texi
View File

@ -19029,7 +19029,7 @@ Set perspective parameter.
Tetrahedron projection.
@item tsp
Truncated square pyramid projection. @i{(output only)}
Truncated square pyramid projection.
@end table

77
libavfilter/vf_v360.c
View File

@ -77,6 +77,7 @@ static const AVOption v360_options[] = {
{"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" },
{ "tsp", "truncated square pyramid", 0, AV_OPT_TYPE_CONST, {.i64=TSPYRAMID}, 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" },
@ -3286,6 +3287,76 @@ static int tspyramid_to_xyz(const V360Context *s,
return 1;
}
/**
* Calculate frame position in tspyramid 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_tspyramid(const V360Context *s,
const float *vec, int width, int height,
int16_t us[4][4], int16_t vs[4][4], float *du, float *dv)
{
float uf, vf;
int ui, vi;
int face;
xyz_to_cube(s, vec, &uf, &vf, &face);
uf = (uf + 1.f) * 0.5f;
vf = (vf + 1.f) * 0.5f;
switch (face) {
case UP:
uf = 0.1875f * vf - 0.375f * uf * vf - 0.125f * uf + 0.8125f;
vf = 0.375f - 0.375f * vf;
break;
case FRONT:
uf = 0.5f * uf;
break;
case DOWN:
uf = 1.f - 0.1875f * vf - 0.5f * uf + 0.375f * uf * vf;
vf = 1.f - 0.375f * vf;
break;
case LEFT:
vf = 0.25f * vf + 0.75f * uf * vf - 0.375f * uf + 0.375f;
uf = 0.1875f * uf + 0.8125f;
break;
case RIGHT:
vf = 0.375f * uf - 0.75f * uf * vf + vf;
uf = 0.1875f * uf + 0.5f;
break;
case BACK:
uf = 0.125f * uf + 0.6875f;
vf = 0.25f * vf + 0.375f;
break;
}
uf *= width;
vf *= height;
ui = floorf(uf);
vi = floorf(vf);
*du = uf - ui;
*dv = vf - vi;
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
us[i][j] = reflectx(ui + j - 1, vi + i - 1, width, height);
vs[i][j] = reflecty(vi + i - 1, height);
}
}
return 1;
}
static void multiply_matrix(float c[3][3], const float a[3][3], const float b[3][3])
{
for (int i = 0; i < 3; i++) {
@ -3727,6 +3798,12 @@ static int config_output(AVFilterLink *outlink)
wf = w * 4.f / 3.f;
hf = h;
break;
case TSPYRAMID:
s->in_transform = xyz_to_tspyramid;
err = 0;
wf = w;
hf = h;
break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified input format is not handled.\n");
return AVERROR_BUG;