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avfilters/vf_v360: add equisolid projection support

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This commit is contained in:
Paul B Mahol 2020-06-22 14:39:35 +02:00
parent 3f2be5372e
commit 44ce333f03
3 changed files with 150 additions and 0 deletions
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20
doc/filters.texi
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@ -19322,6 +19322,26 @@ Truncated square pyramid projection.
@item he
@item hequirect
Half equirectangular projection.
@item equisolid
Equisolid 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
@item interp

1
libavfilter/v360.h
View File

@ -51,6 +51,7 @@ enum Projections {
BARREL_SPLIT,
TSPYRAMID,
HEQUIRECTANGULAR,
EQUISOLID,
NB_PROJECTIONS,
};

129
libavfilter/vf_v360.c
View File

@ -81,6 +81,7 @@ static const AVOption v360_options[] = {
{ "tsp", "truncated square pyramid", 0, AV_OPT_TYPE_CONST, {.i64=TSPYRAMID}, 0, 0, FLAGS, "in" },
{ "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" },
{ "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" },
@ -108,6 +109,7 @@ static const AVOption v360_options[] = {
{ "tsp", "truncated square pyramid", 0, AV_OPT_TYPE_CONST, {.i64=TSPYRAMID}, 0, 0, FLAGS, "out" },
{ "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" },
{ "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" },
@ -1819,6 +1821,112 @@ static int xyz_to_stereographic(const V360Context *s,
return visible;
}
/**
* Prepare data for processing equisolid output format.
*
* @param ctx filter context
*
* @return error code
*/
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);
return 0;
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in equisolid 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 equisolid_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) * 2.f;
const float sin_theta = sinf(theta);
vec[0] = x / r * sin_theta;
vec[1] = y / r * sin_theta;
vec[2] = cosf(theta);
normalize_vector(vec);
return 1;
}
/**
* Prepare data for processing equisolid input format.
*
* @param ctx filter context
*
* @return error code
*/
static int prepare_equisolid_in(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->iflat_range[0] = sinf(FFMIN(s->ih_fov, 359.f) * M_PI / 720.f);
s->iflat_range[1] = sinf(FFMIN(s->iv_fov, 359.f) * M_PI / 720.f);
return 0;
}
/**
* Calculate frame position in equisolid 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_equisolid(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 * 0.5f);
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 = 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.
*
@ -3644,6 +3752,15 @@ 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 EQUISOLID:
{
const float d = 0.5f * hypotf(w, h);
const float l = d / (sinf(d_fov * M_PI / 720.f));
*h_fov = 2.f * asinf(w * 0.5f / l) * 360.f / M_PI;
*v_fov = 2.f * asinf(h * 0.5f / l) * 360.f / M_PI;
}
break;
case STEREOGRAPHIC:
{
const float d = 0.5f * hypotf(w, h);
@ -4014,6 +4131,12 @@ static int config_output(AVFilterLink *outlink)
wf = w * 2.f;
hf = h;
break;
case EQUISOLID:
s->in_transform = xyz_to_equisolid;
err = prepare_equisolid_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;
@ -4150,6 +4273,12 @@ static int config_output(AVFilterLink *outlink)
w = lrintf(wf / 2.f);
h = lrintf(hf);
break;
case EQUISOLID:
s->out_transform = equisolid_to_xyz;
prepare_out = prepare_equisolid_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;