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avfilter/vf_v360: add orthographic projection support

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This commit is contained in:
Paul B Mahol 2020-06-22 20:16:22 +02:00
parent 44ce333f03
commit 00a5df71ad
3 changed files with 156 additions and 2 deletions
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20
doc/filters.texi
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@ -19340,6 +19340,26 @@ If diagonal field of view is set it overrides horizontal and vertical field of v
@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
@item og
Orthographic format.
Format specific options:
@table @option
@item h_fov
@item v_fov
@item d_fov
Set output 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
@end table

1
libavfilter/v360.h
View File

@ -52,6 +52,7 @@ enum Projections {
TSPYRAMID,
HEQUIRECTANGULAR,
EQUISOLID,
ORTHOGRAPHIC,
NB_PROJECTIONS,
};

137
libavfilter/vf_v360.c
View File

@ -82,6 +82,7 @@ static const AVOption v360_options[] = {
{ "hequirect", "half equirectangular", 0, AV_OPT_TYPE_CONST, {.i64=HEQUIRECTANGULAR},0, 0, FLAGS, "in" },
{ "he", "half equirectangular", 0, AV_OPT_TYPE_CONST, {.i64=HEQUIRECTANGULAR},0, 0, FLAGS, "in" },
{ "equisolid", "equisolid", 0, AV_OPT_TYPE_CONST, {.i64=EQUISOLID}, 0, 0, FLAGS, "in" },
{ "og", "orthographic", 0, AV_OPT_TYPE_CONST, {.i64=ORTHOGRAPHIC}, 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" },
@ -110,6 +111,7 @@ static const AVOption v360_options[] = {
{ "hequirect", "half equirectangular", 0, AV_OPT_TYPE_CONST, {.i64=HEQUIRECTANGULAR},0, 0, FLAGS, "out" },
{ "he", "half equirectangular", 0, AV_OPT_TYPE_CONST, {.i64=HEQUIRECTANGULAR},0, 0, FLAGS, "out" },
{ "equisolid", "equisolid", 0, AV_OPT_TYPE_CONST, {.i64=EQUISOLID}, 0, 0, FLAGS, "out" },
{ "og", "orthographic", 0, AV_OPT_TYPE_CONST, {.i64=ORTHOGRAPHIC}, 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" },
@ -1832,8 +1834,8 @@ static int prepare_equisolid_out(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->flat_range[0] = sinf(FFMIN(s->h_fov, 359.f) * M_PI / 720.f);
s->flat_range[1] = sinf(FFMIN(s->v_fov, 359.f) * M_PI / 720.f);
s->flat_range[0] = sinf(s->h_fov * M_PI / 720.f);
s->flat_range[1] = sinf(s->v_fov * M_PI / 720.f);
return 0;
}
@ -1927,6 +1929,111 @@ static int xyz_to_equisolid(const V360Context *s,
return visible;
}
/**
* Prepare data for processing orthographic output format.
*
* @param ctx filter context
*
* @return error code
*/
static int prepare_orthographic_out(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->flat_range[0] = sinf(FFMIN(s->h_fov, 180.f) * M_PI / 360.f);
s->flat_range[1] = sinf(FFMIN(s->v_fov, 180.f) * M_PI / 360.f);
return 0;
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in orthographic format.
*
* @param s filter private context
* @param i horizontal position on frame [0, width)
* @param j vertical position on frame [0, height)
* @param width frame width
* @param height frame height
* @param vec coordinates on sphere
*/
static int orthographic_to_xyz(const V360Context *s,
int i, int j, int width, int height,
float *vec)
{
const float x = ((2.f * i + 1.f) / width - 1.f) * s->flat_range[0];
const float y = ((2.f * j + 1.f) / height - 1.f) * s->flat_range[1];
const float r = hypotf(x, y);
const float theta = asinf(r);
vec[0] = x;
vec[1] = y;
vec[2] = cosf(theta);
normalize_vector(vec);
return 1;
}
/**
* Prepare data for processing orthographic input format.
*
* @param ctx filter context
*
* @return error code
*/
static int prepare_orthographic_in(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->iflat_range[0] = sinf(FFMIN(s->ih_fov, 180.f) * M_PI / 360.f);
s->iflat_range[1] = sinf(FFMIN(s->iv_fov, 180.f) * M_PI / 360.f);
return 0;
}
/**
* Calculate frame position in orthographic 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_orthographic(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 theta = acosf(vec[2]);
const float r = sinf(theta);
const float c = r / hypotf(vec[0], vec[1]);
const float x = vec[0] * c / s->iflat_range[0] * s->input_mirror_modifier[0];
const float y = vec[1] * c / s->iflat_range[1] * s->input_mirror_modifier[1];
const float uf = (x + 1.f) * width / 2.f;
const float vf = (y + 1.f) * height / 2.f;
const int ui = floorf(uf);
const int vi = floorf(vf);
const int visible = vec[2] >= 0.f && isfinite(x) && isfinite(y) && vi >= 0 && vi < height && ui >= 0 && ui < width;
*du = visible ? uf - ui : 0.f;
*dv = visible ? vf - vi : 0.f;
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
us[i][j] = visible ? av_clip(ui + j - 1, 0, width - 1) : 0;
vs[i][j] = visible ? av_clip(vi + i - 1, 0, height - 1) : 0;
}
}
return visible;
}
/**
* Calculate frame position in equirectangular format for corresponding 3D coordinates on sphere.
*
@ -3752,6 +3859,20 @@ static int allocate_plane(V360Context *s, int sizeof_uv, int sizeof_ker, int siz
static void fov_from_dfov(int format, float d_fov, float w, float h, float *h_fov, float *v_fov)
{
switch (format) {
case ORTHOGRAPHIC:
{
const float d = 0.5f * hypotf(w, h);
const float l = sinf(d_fov * M_PI / 360.f) / d;
*h_fov = asinf(w * 0.5 * l) * 360.f / M_PI;
*v_fov = asinf(h * 0.5 * l) * 360.f / M_PI;
if (d_fov > 180.f) {
*h_fov = 180.f - *h_fov;
*v_fov = 180.f - *v_fov;
}
}
break;
case EQUISOLID:
{
const float d = 0.5f * hypotf(w, h);
@ -4137,6 +4258,12 @@ static int config_output(AVFilterLink *outlink)
wf = w;
hf = h / 2.f;
break;
case ORTHOGRAPHIC:
s->in_transform = xyz_to_orthographic;
err = prepare_orthographic_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;
@ -4279,6 +4406,12 @@ static int config_output(AVFilterLink *outlink)
w = lrintf(wf);
h = lrintf(hf * 2.f);
break;
case ORTHOGRAPHIC:
s->out_transform = orthographic_to_xyz;
prepare_out = prepare_orthographic_out;
w = lrintf(wf);
h = lrintf(hf * 2.f);
break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified output format is not handled.\n");
return AVERROR_BUG;