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avfilter/vf_v360: add half equirectangular output format

This commit is contained in:
Paul B Mahol 2020-03-03 12:03:42 +01:00
parent f9cb7cf424
commit ca04231983
2 changed files with 38 additions and 0 deletions
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1
libavfilter/v360.h
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@ -50,6 +50,7 @@ enum Projections {
TETRAHEDRON,
BARREL_SPLIT,
TSPYRAMID,
HEQUIRECTANGULAR,
NB_PROJECTIONS,
};

37
libavfilter/vf_v360.c
View File

@ -103,6 +103,8 @@ static const AVOption v360_options[] = {
{"tetrahedron", "tetrahedron", 0, AV_OPT_TYPE_CONST, {.i64=TETRAHEDRON}, 0, 0, FLAGS, "out" },
{"barrelsplit", "barrel split facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64=BARREL_SPLIT}, 0, 0, FLAGS, "out" },
{ "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" },
{ "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" },
@ -1630,6 +1632,35 @@ static int equirect_to_xyz(const V360Context *s,
return 1;
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in half equirectangular 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 hequirect_to_xyz(const V360Context *s,
int i, int j, int width, int height,
float *vec)
{
const float phi = ((2.f * i + 0.5f) / width - 1.f) * M_PI_2;
const float theta = ((2.f * j + 0.5f) / height - 1.f) * M_PI_2;
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;
return 1;
}
/**
* Prepare data for processing stereographic output format.
*
@ -3934,6 +3965,12 @@ static int config_output(AVFilterLink *outlink)
w = lrintf(wf);
h = lrintf(hf);
break;
case HEQUIRECTANGULAR:
s->out_transform = hequirect_to_xyz;
prepare_out = NULL;
w = lrintf(wf / 2.f);
h = lrintf(hf);
break;
default:
av_log(ctx, AV_LOG_ERROR, "Specified output format is not handled.\n");
return AVERROR_BUG;