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author | Paul B Mahol <onemda@gmail.com> | 2019-09-17 22:15:07 +0200 |
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committer | Paul B Mahol <onemda@gmail.com> | 2019-09-17 22:18:30 +0200 |
commit | 251284e44aa568f344e973d4d0b8f03d2b3734aa (patch) | |
tree | b41d403a3158351d08b162f953b3907ccc407863 | |
parent | 65589ad55349b49fc3e877394249c9291cd3da4a (diff) | |
download | ffmpeg-251284e44aa568f344e973d4d0b8f03d2b3734aa.tar.gz |
avfilter/vf_v360: add mercator projection
-rw-r--r-- | doc/filters.texi | 3 | ||||
-rw-r--r-- | libavfilter/v360.h | 1 | ||||
-rw-r--r-- | libavfilter/vf_v360.c | 78 |
3 files changed, 82 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index bbfdad4d4d..4888869473 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -18057,6 +18057,9 @@ 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 +@item mercator +Mercator format. + @end table @item interp diff --git a/libavfilter/v360.h b/libavfilter/v360.h index a15ff7dbc4..cb968dab46 100644 --- a/libavfilter/v360.h +++ b/libavfilter/v360.h @@ -39,6 +39,7 @@ enum Projections { BARREL, CUBEMAP_1_6, STEREOGRAPHIC, + MERCATOR, NB_PROJECTIONS, }; diff --git a/libavfilter/vf_v360.c b/libavfilter/vf_v360.c index d5b94cf747..f8d3be80a5 100644 --- a/libavfilter/vf_v360.c +++ b/libavfilter/vf_v360.c @@ -65,6 +65,7 @@ static const AVOption v360_options[] = { { "fb", "barrel facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64=BARREL}, 0, 0, FLAGS, "in" }, { "c1x6", "cubemap 1x6", 0, AV_OPT_TYPE_CONST, {.i64=CUBEMAP_1_6}, 0, 0, FLAGS, "in" }, { "sg", "stereographic", 0, AV_OPT_TYPE_CONST, {.i64=STEREOGRAPHIC}, 0, 0, FLAGS, "in" }, + { "mercator", "mercator", 0, AV_OPT_TYPE_CONST, {.i64=MERCATOR}, 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" }, @@ -79,6 +80,7 @@ static const AVOption v360_options[] = { { "fb", "barrel facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64=BARREL}, 0, 0, FLAGS, "out" }, { "c1x6", "cubemap 1x6", 0, AV_OPT_TYPE_CONST, {.i64=CUBEMAP_1_6}, 0, 0, FLAGS, "out" }, { "sg", "stereographic", 0, AV_OPT_TYPE_CONST, {.i64=STEREOGRAPHIC}, 0, 0, FLAGS, "out" }, + { "mercator", "mercator", 0, AV_OPT_TYPE_CONST, {.i64=MERCATOR}, 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" }, @@ -1517,6 +1519,70 @@ static void xyz_to_equirect(const V360Context *s, } /** + * Calculate frame position in mercator format for corresponding 3D coordinates on sphere. + * + * @param s filter 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_mercator(const V360Context *s, + const float *vec, int width, int height, + uint16_t us[4][4], uint16_t vs[4][4], float *du, float *dv) +{ + const float phi = atan2f(vec[0], -vec[2]) * s->input_mirror_modifier[0]; + const float theta = 0.5f * asinhf(vec[1] / sqrtf(1.f - vec[1] * vec[1])) * s->input_mirror_modifier[1]; + float uf, vf; + int ui, vi; + + uf = (phi / M_PI + 1.f) * width / 2.f; + vf = (theta / M_PI + 1.f) * height / 2.f; + ui = floorf(uf); + vi = floorf(vf); + + *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] = mod(ui + j, width); + vs[i + 1][j + 1] = av_clip(vi + i, 0, height - 1); + } + } +} + +/** + * Calculate 3D coordinates on sphere for corresponding frame position in mercator format. + * + * @param s filter 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 mercator_to_xyz(const V360Context *s, + int i, int j, int width, int height, + float *vec) +{ + const float phi = ((2.f * i) / width - 1.f) * M_PI; + const float theta = atanf(sinhf(((2.f * j) / height - 1.f) * 2.f * M_PI)); + + 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; +} + +/** * Prepare data for processing equi-angular cubemap input format. * * @param ctx filter context @@ -2357,6 +2423,12 @@ static int config_output(AVFilterLink *outlink) wf = w; hf = h / 2.f; break; + case MERCATOR: + s->in_transform = xyz_to_mercator; + err = 0; + wf = w; + hf = h; + break; default: av_log(ctx, AV_LOG_ERROR, "Specified input format is not handled.\n"); return AVERROR_BUG; @@ -2421,6 +2493,12 @@ static int config_output(AVFilterLink *outlink) w = roundf(wf); h = roundf(hf * 2.f); break; + case MERCATOR: + s->out_transform = mercator_to_xyz; + prepare_out = NULL; + w = roundf(wf); + h = roundf(hf); + break; default: av_log(ctx, AV_LOG_ERROR, "Specified output format is not handled.\n"); return AVERROR_BUG; |