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avfilter/vf_v360: add support for cylindrical input format

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This commit is contained in:
Paul B Mahol 2020-01-20 23:29:14 +01:00
parent e57b9aa8b1
commit 19f75e7787
2 changed files with 72 additions and 1 deletions
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7
doc/filters.texi
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@ -19010,6 +19010,13 @@ Format specific options:
@item d_fov
Set horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of view.
@item ih_fov
@item iv_fov
@item id_fov
Set input horizontal/vertical/diagonal field of view. Values in degrees.
If diagonal field of view is set it overrides horizontal and vertical field of view.
@end table

66
libavfilter/vf_v360.c
View File

@ -72,6 +72,7 @@ static const AVOption v360_options[] = {
{ "ball", "ball", 0, AV_OPT_TYPE_CONST, {.i64=BALL}, 0, 0, FLAGS, "in" },
{ "hammer", "hammer", 0, AV_OPT_TYPE_CONST, {.i64=HAMMER}, 0, 0, FLAGS, "in" },
{"sinusoidal", "sinusoidal", 0, AV_OPT_TYPE_CONST, {.i64=SINUSOIDAL}, 0, 0, FLAGS, "in" },
{"cylindrical", "cylindrical", 0, AV_OPT_TYPE_CONST, {.i64=CYLINDRICAL}, 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" },
@ -2406,6 +2407,64 @@ static void cylindrical_to_xyz(const V360Context *s,
normalize_vector(vec);
}
/**
* Prepare data for processing cylindrical input format.
*
* @param ctx filter context
*
* @return error code
*/
static int prepare_cylindrical_in(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->iflat_range[0] = M_PI * s->ih_fov / 360.f;
s->iflat_range[1] = tanf(0.5f * s->iv_fov * M_PI / 180.f);
return 0;
}
/**
* Calculate frame position in cylindrical 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 void xyz_to_cylindrical(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] / s->iflat_range[0];
const float theta = atan2f(-vec[1], hypotf(vec[0], vec[2])) * s->input_mirror_modifier[1] / s->iflat_range[1];
int visible, ui, vi;
float uf, vf;
uf = (phi + 1.f) * (width - 1) / 2.f;
vf = (tanf(theta) + 1.f) * height / 2.f;
ui = floorf(uf);
vi = floorf(vf);
visible = vi >= 0 && vi < height && ui >= 0 && ui < width &&
theta <= M_PI * s->iv_fov / 180.f &&
theta >= -M_PI * s->iv_fov / 180.f;
*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] = visible ? av_clip(ui + j, 0, width - 1) : 0;
vs[i + 1][j + 1] = visible ? av_clip(vi + i, 0, height - 1) : 0;
}
}
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in perspective format.
*
@ -3011,7 +3070,6 @@ static int config_output(AVFilterLink *outlink)
hf = h;
break;
case PERSPECTIVE:
case CYLINDRICAL:
case PANNINI:
case FISHEYE:
av_log(ctx, AV_LOG_ERROR, "Supplied format is not accepted as input.\n");
@ -3058,6 +3116,12 @@ static int config_output(AVFilterLink *outlink)
wf = w;
hf = h;
break;
case CYLINDRICAL:
s->in_transform = xyz_to_cylindrical;
err = prepare_cylindrical_in(ctx);
wf = w;
hf = h * 2.f;
break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified input format is not handled.\n");
return AVERROR_BUG;