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avfilter/vf_v360: add cylindrical output projection

This commit is contained in:
Paul B Mahol 2020-01-17 10:46:31 +01:00
parent ab9627223e
commit 7fc28465df
3 changed files with 74 additions and 3 deletions
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13
doc/filters.texi
View File

@ -18990,6 +18990,19 @@ Format specific options:
Set pannini parameter.
@end table
@item cylindrical
Cylindrical projection. @i{(output only)}
Format specific options:
@table @option
@item h_fov
@item v_fov
@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.
@end table
@end table
@item interp

1
libavfilter/v360.h
View File

@ -45,6 +45,7 @@ enum Projections {
SINUSOIDAL,
FISHEYE,
PANNINI,
CYLINDRICAL,
NB_PROJECTIONS,
};

63
libavfilter/vf_v360.c
View File

@ -89,6 +89,7 @@ static const AVOption v360_options[] = {
{"sinusoidal", "sinusoidal", 0, AV_OPT_TYPE_CONST, {.i64=SINUSOIDAL}, 0, 0, FLAGS, "out" },
{ "fisheye", "fisheye", 0, AV_OPT_TYPE_CONST, {.i64=FISHEYE}, 0, 0, FLAGS, "out" },
{ "pannini", "pannini", 0, AV_OPT_TYPE_CONST, {.i64=PANNINI}, 0, 0, FLAGS, "out" },
{"cylindrical", "cylindrical", 0, AV_OPT_TYPE_CONST, {.i64=CYLINDRICAL}, 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" },
@ -2118,8 +2119,8 @@ static int prepare_fisheye_out(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->flat_range[0] = FFMIN(s->h_fov, 359.f) / 180.f;
s->flat_range[1] = FFMIN(s->v_fov, 359.f) / 180.f;
s->flat_range[0] = s->h_fov / 180.f;
s->flat_range[1] = s->v_fov / 180.f;
return 0;
}
@ -2183,6 +2184,55 @@ static void pannini_to_xyz(const V360Context *s,
normalize_vector(vec);
}
/**
* Prepare data for processing cylindrical output format.
*
* @param ctx filter context
*
* @return error code
*/
static int prepare_cylindrical_out(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
s->flat_range[0] = M_PI * s->h_fov / 360.f;
s->flat_range[1] = tanf(0.5f * s->v_fov * M_PI / 180.f);
return 0;
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in cylindrical 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 void cylindrical_to_xyz(const V360Context *s,
int i, int j, int width, int height,
float *vec)
{
const float uf = s->flat_range[0] * ((2.f * i) / width - 1.f);
const float vf = s->flat_range[1] * ((2.f * j) / height - 1.f);
const float phi = uf;
const float theta = atanf(vf);
const float sin_phi = sinf(phi);
const float cos_phi = cosf(phi);
const float sin_theta = sinf(theta);
const float cos_theta = cosf(theta);
vec[0] = cos_theta * sin_phi;
vec[1] = -sin_theta;
vec[2] = -cos_theta * cos_phi;
normalize_vector(vec);
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in dual fisheye format.
*
@ -2719,6 +2769,7 @@ static int config_output(AVFilterLink *outlink)
wf = w;
hf = h / 9.f * 8.f;
break;
case CYLINDRICAL:
case PANNINI:
case FISHEYE:
case FLAT:
@ -2862,10 +2913,16 @@ static int config_output(AVFilterLink *outlink)
break;
case PANNINI:
s->out_transform = pannini_to_xyz;
prepare_out = prepare_fisheye_out;
prepare_out = NULL;
w = roundf(wf);
h = roundf(hf);
break;
case CYLINDRICAL:
s->out_transform = cylindrical_to_xyz;
prepare_out = prepare_cylindrical_out;
w = roundf(wf);
h = roundf(hf * 0.5f);
break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified output format is not handled.\n");
return AVERROR_BUG;