avfilter: add v360 filter

Signed-off-by: Eugene Lyapustin <unishifft@gmail.com>

3 files changed, 1859 insertions, 0 deletions

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index efc7bbb..345f7c9 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -410,6 +410,7 @@ OBJS-$(CONFIG_UNSHARP_FILTER)                += vf_unsharp.o
 OBJS-$(CONFIG_UNSHARP_OPENCL_FILTER)         += vf_unsharp_opencl.o opencl.o \
                                                 opencl/unsharp.o
 OBJS-$(CONFIG_USPP_FILTER)                   += vf_uspp.o
+OBJS-$(CONFIG_V360_FILTER)                   += vf_v360.o
 OBJS-$(CONFIG_VAGUEDENOISER_FILTER)          += vf_vaguedenoiser.o
 OBJS-$(CONFIG_VECTORSCOPE_FILTER)            += vf_vectorscope.o
 OBJS-$(CONFIG_VFLIP_FILTER)                  += vf_vflip.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index abd726d..5799fb4 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -390,6 +390,7 @@ extern AVFilter ff_vf_unpremultiply;
 extern AVFilter ff_vf_unsharp;
 extern AVFilter ff_vf_unsharp_opencl;
 extern AVFilter ff_vf_uspp;
+extern AVFilter ff_vf_v360;
 extern AVFilter ff_vf_vaguedenoiser;
 extern AVFilter ff_vf_vectorscope;
 extern AVFilter ff_vf_vflip;
diff --git a/libavfilter/vf_v360.c b/libavfilter/vf_v360.c
new file mode 100644
index 0000000..d23bcd3
--- /dev/null
+++ b/libavfilter/vf_v360.c
@@ -0,0 +1,1857 @@
+/*
+ * Copyright (c) 2019 Eugene Lyapustin
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * 360 video conversion filter.
+ * Principle of operation:
+ *
+ * (for each pixel in output frame)\n
+ * 1) Calculate OpenGL-like coordinates (x, y, z) for pixel position (i, j)\n
+ * 2) Apply 360 operations (rotation, mirror) to (x, y, z)\n
+ * 3) Calculate pixel position (u, v) in input frame\n
+ * 4) Calculate interpolation window and weight for each pixel
+ *
+ * (for each frame)\n
+ * 5) Remap input frame to output frame using precalculated data\n
+ */
+
+#include "libavutil/eval.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/pixdesc.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+enum Projections {
+    EQUIRECTANGULAR,
+    CUBEMAP_3_2,
+    CUBEMAP_6_1,
+    EQUIANGULAR,
+    FLAT,
+    NB_PROJECTIONS,
+};
+
+enum InterpMethod {
+    NEAREST,
+    BILINEAR,
+    BICUBIC,
+    LANCZOS,
+    NB_INTERP_METHODS,
+};
+
+enum Faces {
+    TOP_LEFT,
+    TOP_MIDDLE,
+    TOP_RIGHT,
+    BOTTOM_LEFT,
+    BOTTOM_MIDDLE,
+    BOTTOM_RIGHT,
+    NB_FACES,
+};
+
+enum Direction {
+    RIGHT,  ///< Axis +X
+    LEFT,   ///< Axis -X
+    UP,     ///< Axis +Y
+    DOWN,   ///< Axis -Y
+    FRONT,  ///< Axis -Z
+    BACK,   ///< Axis +Z
+    NB_DIRECTIONS,
+};
+
+enum Rotation {
+    ROT_0,
+    ROT_90,
+    ROT_180,
+    ROT_270,
+    NB_ROTATIONS,
+};
+
+typedef struct V360Context {
+    const AVClass *class;
+    int in, out;
+    int interp;
+    int width, height;
+    char* in_forder;
+    char* out_forder;
+    char* in_frot;
+    char* out_frot;
+
+    int in_cubemap_face_order[6];
+    int out_cubemap_direction_order[6];
+    int in_cubemap_face_rotation[6];
+    int out_cubemap_face_rotation[6];
+
+    float yaw, pitch, roll;
+
+    int h_flip, v_flip, d_flip;
+
+    float h_fov, v_fov;
+    float flat_range[3];
+
+    int planewidth[4], planeheight[4];
+    int inplanewidth[4], inplaneheight[4];
+    int nb_planes;
+
+    void *remap[4];
+
+    int (*remap_slice)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
+} V360Context;
+
+typedef struct ThreadData {
+    V360Context *s;
+    AVFrame *in;
+    AVFrame *out;
+    int nb_planes;
+} ThreadData;
+
+#define OFFSET(x) offsetof(V360Context, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption v360_options[] = {
+    {     "input", "set input projection",              OFFSET(in), AV_OPT_TYPE_INT,    {.i64=EQUIRECTANGULAR}, 0,    NB_PROJECTIONS-1, FLAGS, "in" },
+    {         "e", "equirectangular",                            0, AV_OPT_TYPE_CONST,  {.i64=EQUIRECTANGULAR}, 0,                   0, FLAGS, "in" },
+    {      "c3x2", "cubemap3x2",                                 0, AV_OPT_TYPE_CONST,  {.i64=CUBEMAP_3_2},     0,                   0, FLAGS, "in" },
+    {      "c6x1", "cubemap6x1",                                 0, AV_OPT_TYPE_CONST,  {.i64=CUBEMAP_6_1},     0,                   0, FLAGS, "in" },
+    {       "eac", "equi-angular",                               0, AV_OPT_TYPE_CONST,  {.i64=EQUIANGULAR},     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" },
+    {      "c3x2", "cubemap3x2",                                 0, AV_OPT_TYPE_CONST,  {.i64=CUBEMAP_3_2},     0,                   0, FLAGS, "out" },
+    {      "c6x1", "cubemap6x1",                                 0, AV_OPT_TYPE_CONST,  {.i64=CUBEMAP_6_1},     0,                   0, FLAGS, "out" },
+    {       "eac", "equi-angular",                               0, AV_OPT_TYPE_CONST,  {.i64=EQUIANGULAR},     0,                   0, FLAGS, "out" },
+    {      "flat", "regular video",                              0, AV_OPT_TYPE_CONST,  {.i64=FLAT},            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" },
+    {      "line", "bilinear interpolation",                     0, AV_OPT_TYPE_CONST,  {.i64=BILINEAR},        0,                   0, FLAGS, "interp" },
+    {    "linear", "bilinear interpolation",                     0, AV_OPT_TYPE_CONST,  {.i64=BILINEAR},        0,                   0, FLAGS, "interp" },
+    {      "cube", "bicubic interpolation",                      0, AV_OPT_TYPE_CONST,  {.i64=BICUBIC},         0,                   0, FLAGS, "interp" },
+    {     "cubic", "bicubic interpolation",                      0, AV_OPT_TYPE_CONST,  {.i64=BICUBIC},         0,                   0, FLAGS, "interp" },
+    {      "lanc", "lanczos interpolation",                      0, AV_OPT_TYPE_CONST,  {.i64=LANCZOS},         0,                   0, FLAGS, "interp" },
+    {   "lanczos", "lanczos interpolation",                      0, AV_OPT_TYPE_CONST,  {.i64=LANCZOS},         0,                   0, FLAGS, "interp" },
+    {         "w", "output width",                   OFFSET(width), AV_OPT_TYPE_INT,    {.i64=0},               0,             INT_MAX, FLAGS, "w"},
+    {         "h", "output height",                 OFFSET(height), AV_OPT_TYPE_INT,    {.i64=0},               0,             INT_MAX, FLAGS, "h"},
+    { "in_forder", "input cubemap face order",   OFFSET(in_forder), AV_OPT_TYPE_STRING, {.str="rludfb"},        0,     NB_DIRECTIONS-1, FLAGS, "in_forder"},
+    {"out_forder", "output cubemap face order", OFFSET(out_forder), AV_OPT_TYPE_STRING, {.str="rludfb"},        0,     NB_DIRECTIONS-1, FLAGS, "out_forder"},
+    {   "in_frot", "input cubemap face rotation",  OFFSET(in_frot), AV_OPT_TYPE_STRING, {.str="000000"},        0,     NB_DIRECTIONS-1, FLAGS, "in_frot"},
+    {  "out_frot", "output cubemap face rotation",OFFSET(out_frot), AV_OPT_TYPE_STRING, {.str="000000"},        0,     NB_DIRECTIONS-1, FLAGS, "out_frot"},
+    {       "yaw", "yaw rotation",                     OFFSET(yaw), AV_OPT_TYPE_FLOAT,  {.dbl=0.f},        -180.f,               180.f, FLAGS, "yaw"},
+    {     "pitch", "pitch rotation",                 OFFSET(pitch), AV_OPT_TYPE_FLOAT,  {.dbl=0.f},        -180.f,               180.f, FLAGS, "pitch"},
+    {      "roll", "roll rotation",                   OFFSET(roll), AV_OPT_TYPE_FLOAT,  {.dbl=0.f},        -180.f,               180.f, FLAGS, "roll"},
+    {     "h_fov", "horizontal field of view",       OFFSET(h_fov), AV_OPT_TYPE_FLOAT,  {.dbl=90.f},          0.f,               180.f, FLAGS, "h_fov"},
+    {     "v_fov", "vertical field of view",         OFFSET(v_fov), AV_OPT_TYPE_FLOAT,  {.dbl=45.f},          0.f,                90.f, FLAGS, "v_fov"},
+    {    "h_flip", "flip video horizontally",       OFFSET(h_flip), AV_OPT_TYPE_BOOL,   {.i64=0},               0,                   1, FLAGS, "h_flip"},
+    {    "v_flip", "flip video vertically",         OFFSET(v_flip), AV_OPT_TYPE_BOOL,   {.i64=0},               0,                   1, FLAGS, "v_flip"},
+    {    "d_flip", "flip video indepth",            OFFSET(d_flip), AV_OPT_TYPE_BOOL,   {.i64=0},               0,                   1, FLAGS, "d_flip"},
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(v360);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        // YUVA444
+        AV_PIX_FMT_YUVA444P,   AV_PIX_FMT_YUVA444P9,
+        AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA444P12,
+        AV_PIX_FMT_YUVA444P16,
+
+        // YUVA422
+        AV_PIX_FMT_YUVA422P,   AV_PIX_FMT_YUVA422P9,
+        AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA422P12,
+        AV_PIX_FMT_YUVA422P16,
+
+        // YUVA420
+        AV_PIX_FMT_YUVA420P,   AV_PIX_FMT_YUVA420P9,
+        AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA420P16,
+
+        // YUVJ
+        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
+        AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
+        AV_PIX_FMT_YUVJ411P,
+
+        // YUV444
+        AV_PIX_FMT_YUV444P,   AV_PIX_FMT_YUV444P9,
+        AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUV444P12,
+        AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV444P16,
+
+        // YUV440
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV440P10,
+        AV_PIX_FMT_YUV440P12,
+
+        // YUV422
+        AV_PIX_FMT_YUV422P,   AV_PIX_FMT_YUV422P9,
+        AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV422P12,
+        AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV422P16,
+
+        // YUV420
+        AV_PIX_FMT_YUV420P,   AV_PIX_FMT_YUV420P9,
+        AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV420P12,
+        AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV420P16,
+
+        // YUV411
+        AV_PIX_FMT_YUV411P,
+
+        // YUV410
+        AV_PIX_FMT_YUV410P,
+
+        // GBR
+        AV_PIX_FMT_GBRP,   AV_PIX_FMT_GBRP9,
+        AV_PIX_FMT_GBRP10, AV_PIX_FMT_GBRP12,
+        AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
+
+        // GBRA
+        AV_PIX_FMT_GBRAP,   AV_PIX_FMT_GBRAP10,
+        AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
+
+        // GRAY
+        AV_PIX_FMT_GRAY8,  AV_PIX_FMT_GRAY9,
+        AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12,
+        AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
+
+        AV_PIX_FMT_NONE
+    };
+
+    AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+    if (!fmts_list)
+        return AVERROR(ENOMEM);
+    return ff_set_common_formats(ctx, fmts_list);
+}
+
+typedef struct XYRemap1 {
+    uint16_t u;
+    uint16_t v;
+} XYRemap1;
+
+/**
+ * Generate no-interpolation remapping function with a given pixel depth.
+ *
+ * @param bits number of bits per pixel
+ * @param div number of bytes per pixel
+ */
+#define DEFINE_REMAP1(bits, div)                                                             \
+static int remap1_##bits##bit_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) \
+{                                                                                            \
+    ThreadData *td = (ThreadData*)arg;                                                       \
+    const V360Context *s = td->s;                                                            \
+    const AVFrame *in = td->in;                                                              \
+    AVFrame *out = td->out;                                                                  \
+                                                                                             \
+    int plane, x, y;                                                                         \
+                                                                                             \
+    for (plane = 0; plane < td->nb_planes; plane++) {                                        \
+        const int in_linesize  = in->linesize[plane]  / div;                                 \
+        const int out_linesize = out->linesize[plane] / div;                                 \
+        const uint##bits##_t *src = (const uint##bits##_t *)in->data[plane];                 \
+        uint##bits##_t *dst = (uint##bits##_t *)out->data[plane];                            \
+        const XYRemap1 *remap = s->remap[plane];                                             \
+        const int width = s->planewidth[plane];                                              \
+        const int height = s->planeheight[plane];                                            \
+                                                                                             \
+        const int slice_start = (height *  jobnr     ) / nb_jobs;                            \
+        const int slice_end   = (height * (jobnr + 1)) / nb_jobs;                            \
+                                                                                             \
+        for (y = slice_start; y < slice_end; y++) {                                          \
+            uint##bits##_t *d = dst + y * out_linesize;                                      \
+            for (x = 0; x < width; x++) {                                                    \
+                const XYRemap1 *r = &remap[y * width + x];                                   \
+                                                                                             \
+                *d++ = src[r->v * in_linesize + r->u];                                       \
+            }                                                                                \
+        }                                                                                    \
+    }                                                                                        \
+                                                                                             \
+    return 0;                                                                                \
+}
+
+DEFINE_REMAP1( 8, 1)
+DEFINE_REMAP1(16, 2)
+
+typedef struct XYRemap2 {
+    uint16_t u[2][2];
+    uint16_t v[2][2];
+    float ker[2][2];
+} XYRemap2;
+
+typedef struct XYRemap4 {
+    uint16_t u[4][4];
+    uint16_t v[4][4];
+    float ker[4][4];
+} XYRemap4;
+
+/**
+ * Generate remapping function with a given window size and pixel depth.
+ *
+ * @param window_size size of interpolation window
+ * @param bits number of bits per pixel
+ * @param div number of bytes per pixel
+ */
+#define DEFINE_REMAP(window_size, bits, div)                                                               \
+static int remap##window_size##_##bits##bit_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) \
+{                                                                                                          \
+    ThreadData *td = (ThreadData*)arg;                                                                     \
+    const V360Context *s = td->s;                                                                          \
+    const AVFrame *in = td->in;                                                                            \
+    AVFrame *out = td->out;                                                                                \
+                                                                                                           \
+    int plane, x, y, i, j;                                                                                 \
+                                                                                                           \
+    for (plane = 0; plane < td->nb_planes; plane++) {                                                      \
+        const int in_linesize  = in->linesize[plane]  / div;                                               \
+        const int out_linesize = out->linesize[plane] / div;                                               \
+        const uint##bits##_t *src = (const uint##bits##_t *)in->data[plane];                               \
+        uint##bits##_t *dst = (uint##bits##_t *)out->data[plane];                                          \
+        const XYRemap##window_size *remap = s->remap[plane];                                               \
+        const int width = s->planewidth[plane];                                                            \
+        const int height = s->planeheight[plane];                                                          \
+                                                                                                           \
+        const int slice_start = (height *  jobnr     ) / nb_jobs;                                          \
+        const int slice_end   = (height * (jobnr + 1)) / nb_jobs;                                          \
+                                                                                                           \
+        for (y = slice_start; y < slice_end; y++) {                                                        \
+            uint##bits##_t *d = dst + y * out_linesize;                                                    \
+            for (x = 0; x < width; x++) {                                                                  \
+                const XYRemap##window_size *r = &remap[y * width + x];                                     \
+                float tmp = 0.f;                                                                           \
+                                                                                                           \
+                for (i = 0; i < window_size; i++) {                                                        \
+                    for (j = 0; j < window_size; j++) {                                                    \
+                        tmp += r->ker[i][j] * src[r->v[i][j] * in_linesize + r->u[i][j]];                  \
+                    }                                                                                      \
+                }                                                                                          \
+                                                                                                           \
+                *d++ = av_clip_uint##bits(roundf(tmp));                                                    \
+            }                                                                                              \
+        }                                                                                                  \
+    }                                                                                                      \
+                                                                                                           \
+    return 0;                                                                                              \
+}
+
+DEFINE_REMAP(2,  8, 1)
+DEFINE_REMAP(4,  8, 1)
+DEFINE_REMAP(2, 16, 2)
+DEFINE_REMAP(4, 16, 2)
+
+/**
+ * Save nearest pixel coordinates for remapping.
+ *
+ * @param du horizontal relative coordinate
+ * @param dv vertical relative coordinate
+ * @param shift shift for remap array
+ * @param r_tmp calculated 4x4 window
+ * @param r_void remap data
+ */
+static void nearest_kernel(float du, float dv, int shift, const XYRemap4 *r_tmp, void *r_void)
+{
+    XYRemap1 *r = (XYRemap1*)r_void + shift;
+    const int i = roundf(dv) + 1;
+    const int j = roundf(du) + 1;
+
+    r->u = r_tmp->u[i][j];
+    r->v = r_tmp->v[i][j];
+}
+
+/**
+ * Calculate kernel for bilinear interpolation.
+ *
+ * @param du horizontal relative coordinate
+ * @param dv vertical relative coordinate
+ * @param shift shift for remap array
+ * @param r_tmp calculated 4x4 window
+ * @param r_void remap data
+ */
+static void bilinear_kernel(float du, float dv, int shift, const XYRemap4 *r_tmp, void *r_void)
+{
+    XYRemap2 *r = (XYRemap2*)r_void + shift;
+    int i, j;
+
+    for (i = 0; i < 2; i++) {
+        for (j = 0; j < 2; j++) {
+            r->u[i][j] = r_tmp->u[i + 1][j + 1];
+            r->v[i][j] = r_tmp->v[i + 1][j + 1];
+        }
+    }
+
+    r->ker[0][0] = (1.f - du) * (1.f - dv);
+    r->ker[0][1] =        du  * (1.f - dv);
+    r->ker[1][0] = (1.f - du) *        dv;
+    r->ker[1][1] =        du  *        dv;
+}
+
+/**
+ * Calculate 1-dimensional cubic coefficients.
+ *
+ * @param t relative coordinate
+ * @param coeffs coefficients
+ */
+static inline void calculate_bicubic_coeffs(float t, float *coeffs)
+{
+    const float tt  = t * t;
+    const float ttt = t * t * t;
+
+    coeffs[0] =     - t / 3.f + tt / 2.f - ttt / 6.f;
+    coeffs[1] = 1.f - t / 2.f - tt       + ttt / 2.f;
+    coeffs[2] =       t       + tt / 2.f - ttt / 2.f;
+    coeffs[3] =     - t / 6.f            + ttt / 6.f;
+}
+
+/**
+ * Calculate kernel for bicubic interpolation.
+ *
+ * @param du horizontal relative coordinate
+ * @param dv vertical relative coordinate
+ * @param shift shift for remap array
+ * @param r_tmp calculated 4x4 window
+ * @param r_void remap data
+ */
+static void bicubic_kernel(float du, float dv, int shift, const XYRemap4 *r_tmp, void *r_void)
+{
+    XYRemap4 *r = (XYRemap4*)r_void + shift;
+    int i, j;
+    float du_coeffs[4];
+    float dv_coeffs[4];
+
+    calculate_bicubic_coeffs(du, du_coeffs);
+    calculate_bicubic_coeffs(dv, dv_coeffs);
+
+    for (i = 0; i < 4; i++) {
+        for (j = 0; j < 4; j++) {
+            r->u[i][j] = r_tmp->u[i][j];
+            r->v[i][j] = r_tmp->v[i][j];
+            r->ker[i][j] = du_coeffs[j] * dv_coeffs[i];
+        }
+    }
+}
+
+/**
+ * Calculate 1-dimensional lanczos coefficients.
+ *
+ * @param t relative coordinate
+ * @param coeffs coefficients
+ */
+static inline void calculate_lanczos_coeffs(float t, float *coeffs)
+{
+    int i;
+    float sum = 0.f;
+
+    for (i = 0; i < 4; i++) {
+        const float x = M_PI * (t - i + 1);
+        if (x == 0.f) {
+            coeffs[i] = 1.f;
+        } else {
+            coeffs[i] = sinf(x) * sinf(x / 2.f) / (x * x / 2.f);
+        }
+        sum += coeffs[i];
+    }
+
+    for (i = 0; i < 4; i++) {
+        coeffs[i] /= sum;
+    }
+}
+
+/**
+ * Calculate kernel for lanczos interpolation.
+ *
+ * @param du horizontal relative coordinate
+ * @param dv vertical relative coordinate
+ * @param shift shift for remap array
+ * @param r_tmp calculated 4x4 window
+ * @param r_void remap data
+ */
+static void lanczos_kernel(float du, float dv, int shift, const XYRemap4 *r_tmp, void *r_void)
+{
+    XYRemap4 *r = (XYRemap4*)r_void + shift;
+    int i, j;
+    float du_coeffs[4];
+    float dv_coeffs[4];
+
+    calculate_lanczos_coeffs(du, du_coeffs);
+    calculate_lanczos_coeffs(dv, dv_coeffs);
+
+    for (i = 0; i < 4; i++) {
+        for (j = 0; j < 4; j++) {
+            r->u[i][j] = r_tmp->u[i][j];
+            r->v[i][j] = r_tmp->v[i][j];
+            r->ker[i][j] = du_coeffs[j] * dv_coeffs[i];
+        }
+    }
+}
+
+/**
+ * Modulo operation with only positive remainders.
+ *
+ * @param a dividend
+ * @param b divisor
+ *
+ * @return positive remainder of (a / b)
+ */
+static inline int mod(int a, int b)
+{
+    const int res = a % b;
+    if (res < 0) {
+        return res + b;
+    } else {
+        return res;
+    }
+}
+
+/**
+ * Convert char to corresponding direction.
+ * Used for cubemap options.
+ */
+static int get_direction(char c)
+{
+    switch (c) {
+    case 'r':
+        return RIGHT;
+    case 'l':
+        return LEFT;
+    case 'u':
+        return UP;
+    case 'd':
+        return DOWN;
+    case 'f':
+        return FRONT;
+    case 'b':
+        return BACK;
+    default:
+        return -1;
+    }
+}
+
+/**
+ * Convert char to corresponding rotation angle.
+ * Used for cubemap options.
+ */
+static int get_rotation(char c)
+{
+    switch (c) {
+    case '0':
+        return ROT_0;
+    case '1':
+        return ROT_90;
+    case '2':
+        return ROT_180;
+    case '3':
+        return ROT_270;
+    default:
+        return -1;
+    }
+}
+
+/**
+ * Prepare data for processing cubemap input format.
+ *
+ * @param ctx filter context
+ *
+ * @return error code
+ */
+static int prepare_cube_in(AVFilterContext *ctx)
+{
+    V360Context *s = ctx->priv;
+
+    for (int face = 0; face < NB_FACES; face++) {
+        const char c = s->in_forder[face];
+        int direction;
+
+        if (c == '\0') {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incomplete in_forder option. Direction for all 6 faces should be specified.\n");
+            return AVERROR(EINVAL);
+        }
+
+        direction = get_direction(c);
+        if (direction == -1) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incorrect direction symbol '%c' in in_forder option.\n", c);
+            return AVERROR(EINVAL);
+        }
+
+        s->in_cubemap_face_order[direction] = face;
+    }
+
+    for (int face = 0; face < NB_FACES; face++) {
+        const char c = s->in_frot[face];
+        int rotation;
+
+        if (c == '\0') {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incomplete in_frot option. Rotation for all 6 faces should be specified.\n");
+            return AVERROR(EINVAL);
+        }
+
+        rotation = get_rotation(c);
+        if (rotation == -1) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incorrect rotation symbol '%c' in in_frot option.\n", c);
+            return AVERROR(EINVAL);
+        }
+
+        s->in_cubemap_face_rotation[face] = rotation;
+    }
+
+    return 0;
+}
+
+/**
+ * Prepare data for processing cubemap output format.
+ *
+ * @param ctx filter context
+ *
+ * @return error code
+ */
+static int prepare_cube_out(AVFilterContext *ctx)
+{
+    V360Context *s = ctx->priv;
+
+    for (int face = 0; face < NB_FACES; face++) {
+        const char c = s->out_forder[face];
+        int direction;
+
+        if (c == '\0') {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incomplete out_forder option. Direction for all 6 faces should be specified.\n");
+            return AVERROR(EINVAL);
+        }
+
+        direction = get_direction(c);
+        if (direction == -1) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incorrect direction symbol '%c' in out_forder option.\n", c);
+            return AVERROR(EINVAL);
+        }
+
+        s->out_cubemap_direction_order[face] = direction;
+    }
+
+    for (int face = 0; face < NB_FACES; face++) {
+        const char c = s->out_frot[face];
+        int rotation;
+
+        if (c == '\0') {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incomplete out_frot option. Rotation for all 6 faces should be specified.\n");
+            return AVERROR(EINVAL);
+        }
+
+        rotation = get_rotation(c);
+        if (rotation == -1) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Incorrect rotation symbol '%c' in out_frot option.\n", c);
+            return AVERROR(EINVAL);
+        }
+
+        s->out_cubemap_face_rotation[face] = rotation;
+    }
+
+    return 0;
+}
+
+static inline void rotate_cube_face(float *uf, float *vf, int rotation)
+{
+    float tmp;
+
+    switch (rotation) {
+    case ROT_0:
+        break;
+    case ROT_90:
+        tmp =  *uf;
+        *uf = -*vf;
+        *vf =  tmp;
+        break;
+    case ROT_180:
+        *uf = -*uf;
+        *vf = -*vf;
+        break;
+    case ROT_270:
+        tmp = -*uf;
+        *uf =  *vf;
+        *vf =  tmp;
+        break;
+    }
+}
+
+static inline void rotate_cube_face_inverse(float *uf, float *vf, int rotation)
+{
+    float tmp;
+
+    switch (rotation) {
+    case ROT_0:
+        break;
+    case ROT_90:
+        tmp = -*uf;
+        *uf =  *vf;
+        *vf =  tmp;
+        break;
+    case ROT_180:
+        *uf = -*uf;
+        *vf = -*vf;
+        break;
+    case ROT_270:
+        tmp =  *uf;
+        *uf = -*vf;
+        *vf =  tmp;
+        break;
+    }
+}
+
+/**
+ * Calculate 3D coordinates on sphere for corresponding cubemap position.
+ * Common operation for every cubemap.
+ *
+ * @param s filter context
+ * @param uf horizontal cubemap coordinate [0, 1)
+ * @param vf vertical cubemap coordinate [0, 1)
+ * @param face face of cubemap
+ * @param vec coordinates on sphere
+ */
+static void cube_to_xyz(const V360Context *s,
+                        float uf, float vf, int face,
+                        float *vec)
+{
+    const int direction = s->out_cubemap_direction_order[face];
+    float norm;
+    float l_x, l_y, l_z;
+
+    rotate_cube_face_inverse(&uf, &vf, s->out_cubemap_face_rotation[face]);
+
+    switch (direction) {
+    case RIGHT:
+        l_x =  1.f;
+        l_y = -vf;
+        l_z =  uf;
+        break;
+    case LEFT:
+        l_x = -1.f;
+        l_y = -vf;
+        l_z = -uf;
+        break;
+    case UP:
+        l_x =  uf;
+        l_y =  1.f;
+        l_z = -vf;
+        break;
+    case DOWN:
+        l_x =  uf;
+        l_y = -1.f;
+        l_z =  vf;
+        break;
+    case FRONT:
+        l_x =  uf;
+        l_y = -vf;
+        l_z = -1.f;
+        break;
+    case BACK:
+        l_x = -uf;
+        l_y = -vf;
+        l_z =  1.f;
+        break;
+    }
+
+    norm = sqrtf(l_x * l_x + l_y * l_y + l_z * l_z);
+    vec[0] = l_x / norm;
+    vec[1] = l_y / norm;
+    vec[2] = l_z / norm;
+}
+
+/**
+ * Calculate cubemap position for corresponding 3D coordinates on sphere.
+ * Common operation for every cubemap.
+ *
+ * @param s filter context
+ * @param vec coordinated on sphere
+ * @param uf horizontal cubemap coordinate [0, 1)
+ * @param vf vertical cubemap coordinate [0, 1)
+ * @param direction direction of view
+ */
+static void xyz_to_cube(const V360Context *s,
+                        const float *vec,
+                        float *uf, float *vf, int *direction)
+{
+    const float phi   = atan2f(vec[0], -vec[2]);
+    const float theta = asinf(-vec[1]);
+    float phi_norm, theta_threshold;
+    int face;
+
+    if (phi >= -M_PI_4 && phi < M_PI_4) {
+        *direction = FRONT;
+        phi_norm = phi;
+    } else if (phi >= -(M_PI_2 + M_PI_4) && phi < -M_PI_4) {
+        *direction = LEFT;
+        phi_norm = phi + M_PI_2;
+    } else if (phi >= M_PI_4 && phi < M_PI_2 + M_PI_4) {
+        *direction = RIGHT;
+        phi_norm = phi - M_PI_2;
+    } else {
+        *direction = BACK;
+        phi_norm = phi + ((phi > 0.f) ? -M_PI : M_PI);
+    }
+
+    theta_threshold = atanf(cosf(phi_norm));
+    if (theta > theta_threshold) {
+        *direction = DOWN;
+    } else if (theta < -theta_threshold) {
+        *direction = UP;
+    }
+
+    switch (*direction) {
+    case RIGHT:
+        *uf =  vec[2] / vec[0];
+        *vf = -vec[1] / vec[0];
+        break;
+    case LEFT:
+        *uf =  vec[2] / vec[0];
+        *vf =  vec[1] / vec[0];
+        break;
+    case UP:
+        *uf =  vec[0] / vec[1];
+        *vf = -vec[2] / vec[1];
+        break;
+    case DOWN:
+        *uf = -vec[0] / vec[1];
+        *vf = -vec[2] / vec[1];
+        break;
+    case FRONT:
+        *uf = -vec[0] / vec[2];
+        *vf =  vec[1] / vec[2];
+        break;
+    case BACK:
+        *uf = -vec[0] / vec[2];
+        *vf = -vec[1] / vec[2];
+        break;
+    }
+
+    face = s->in_cubemap_face_order[*direction];
+    rotate_cube_face(uf, vf, s->in_cubemap_face_rotation[face]);
+}
+
+/**
+ * Find position on another cube face in case of overflow/underflow.
+ * Used for calculation of interpolation window.
+ *
+ * @param s filter context
+ * @param uf horizontal cubemap coordinate
+ * @param vf vertical cubemap coordinate
+ * @param direction direction of view
+ * @param new_uf new horizontal cubemap coordinate
+ * @param new_vf new vertical cubemap coordinate
+ * @param face face position on cubemap
+ */
+static void process_cube_coordinates(const V360Context *s,
+                                float uf, float vf, int direction,
+                                float *new_uf, float *new_vf, int *face)
+{
+    /*
+     *  Cubemap orientation
+     *
+     *           width
+     *         <------->
+     *         +-------+
+     *         |       |                              U
+     *         | up    |                   h       ------->
+     * +-------+-------+-------+-------+ ^ e      |
+     * |       |       |       |       | | i    V |
+     * | left  | front | right | back  | | g      |
+     * +-------+-------+-------+-------+ v h      v
+     *         |       |                   t
+     *         | down  |
+     *         +-------+
+     */
+
+    *face = s->in_cubemap_face_order[direction];
+    rotate_cube_face_inverse(&uf, &vf, s->in_cubemap_face_rotation[*face]);
+
+    if ((uf < -1.f || uf >= 1.f) && (vf < -1.f || vf >= 1.f)) {
+        // There are no pixels to use in this case
+        *new_uf = uf;
+        *new_vf = vf;
+    } else if (uf < -1.f) {
+        uf += 2.f;
+        switch (direction) {
+        case RIGHT:
+            direction = FRONT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case LEFT:
+            direction = BACK;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case UP:
+            direction = LEFT;
+            *new_uf =  vf;
+            *new_vf = -uf;
+            break;
+        case DOWN:
+            direction = LEFT;
+            *new_uf = -vf;
+            *new_vf =  uf;
+            break;
+        case FRONT:
+            direction = LEFT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case BACK:
+            direction = RIGHT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        }
+    } else if (uf >= 1.f) {
+        uf -= 2.f;
+        switch (direction) {
+        case RIGHT:
+            direction = BACK;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case LEFT:
+            direction = FRONT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case UP:
+            direction = RIGHT;
+            *new_uf = -vf;
+            *new_vf =  uf;
+            break;
+        case DOWN:
+            direction = RIGHT;
+            *new_uf =  vf;
+            *new_vf = -uf;
+            break;
+        case FRONT:
+            direction = RIGHT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case BACK:
+            direction = LEFT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        }
+    } else if (vf < -1.f) {
+        vf += 2.f;
+        switch (direction) {
+        case RIGHT:
+            direction = UP;
+            *new_uf =  vf;
+            *new_vf = -uf;
+            break;
+        case LEFT:
+            direction = UP;
+            *new_uf = -vf;
+            *new_vf =  uf;
+            break;
+        case UP:
+            direction = BACK;
+            *new_uf = -uf;
+            *new_vf = -vf;
+            break;
+        case DOWN:
+            direction = FRONT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case FRONT:
+            direction = UP;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case BACK:
+            direction = UP;
+            *new_uf = -uf;
+            *new_vf = -vf;
+            break;
+        }
+    } else if (vf >= 1.f) {
+        vf -= 2.f;
+        switch (direction) {
+        case RIGHT:
+            direction = DOWN;
+            *new_uf = -vf;
+            *new_vf =  uf;
+            break;
+        case LEFT:
+            direction = DOWN;
+            *new_uf =  vf;
+            *new_vf = -uf;
+            break;
+        case UP:
+            direction = FRONT;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case DOWN:
+            direction = BACK;
+            *new_uf = -uf;
+            *new_vf = -vf;
+            break;
+        case FRONT:
+            direction = DOWN;
+            *new_uf =  uf;
+            *new_vf =  vf;
+            break;
+        case BACK:
+            direction = DOWN;
+            *new_uf = -uf;
+            *new_vf = -vf;
+            break;
+        }
+    } else {
+        // Inside cube face
+        *new_uf = uf;
+        *new_vf = vf;
+    }
+
+    *face = s->in_cubemap_face_order[direction];
+    rotate_cube_face(new_uf, new_vf, s->in_cubemap_face_rotation[*face]);
+}
+
+/**
+ * Calculate 3D coordinates on sphere for corresponding frame position in cubemap3x2 format.
+ *
+ * @param s filter context
+ * @param i horizontal position on frame [0, height)
+ * @param j vertical position on frame [0, width)
+ * @param width frame width
+ * @param height frame height
+ * @param vec coordinates on sphere
+ */
+static void cube3x2_to_xyz(const V360Context *s,
+                           int i, int j, int width, int height,
+                           float *vec)
+{
+    const float ew = width  / 3.f;
+    const float eh = height / 2.f;
+
+    const int u_face = floorf(i / ew);
+    const int v_face = floorf(j / eh);
+    const int face = u_face + 3 * v_face;
+
+    const int u_shift = ceilf(ew * u_face);
+    const int v_shift = ceilf(eh * v_face);
+    const int ewi = ceilf(ew * (u_face + 1)) - u_shift;
+    const int ehi = ceilf(eh * (v_face + 1)) - v_shift;
+
+    const float uf = 2.f * (i - u_shift) / ewi - 1.f;
+    const float vf = 2.f * (j - v_shift) / ehi - 1.f;
+
+    cube_to_xyz(s, uf, vf, face, vec);
+}
+
+/**
+ * Calculate frame position in cubemap3x2 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_cube3x2(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 ew = width  / 3.f;
+    const float eh = height / 2.f;
+    float uf, vf;
+    int ui, vi;
+    int ewi, ehi;
+    int i, j;
+    int direction, face;
+    int u_face, v_face;
+
+    xyz_to_cube(s, vec, &uf, &vf, &direction);
+
+    face = s->in_cubemap_face_order[direction];
+    u_face = face % 3;
+    v_face = face / 3;
+    ewi = ceilf(ew * (u_face + 1)) - ceilf(ew * u_face);
+    ehi = ceilf(eh * (v_face + 1)) - ceilf(eh * v_face);
+
+    uf = 0.5f * ewi * (uf + 1.f);
+    vf = 0.5f * ehi * (vf + 1.f);
+
+    ui = floorf(uf);
+    vi = floorf(vf);
+
+    *du = uf - ui;
+    *dv = vf - vi;
+
+    for (i = -1; i < 3; i++) {
+        for (j = -1; j < 3; j++) {
+            float u, v;
+            int u_shift, v_shift;
+            int new_ewi, new_ehi;
+
+            process_cube_coordinates(s, 2.f * (ui + j) / ewi - 1.f,
+                                        2.f * (vi + i) / ehi - 1.f,
+                                        direction, &u, &v, &face);
+            u_face = face % 3;
+            v_face = face / 3;
+            u_shift = ceilf(ew * u_face);
+            v_shift = ceilf(eh * v_face);
+            new_ewi = ceilf(ew * (u_face + 1)) - u_shift;
+            new_ehi = ceilf(eh * (v_face + 1)) - v_shift;
+
+            us[i + 1][j + 1] = u_shift + av_clip(roundf(0.5f * new_ewi * (u + 1.f)), 0, new_ewi - 1);
+            vs[i + 1][j + 1] = v_shift + av_clip(roundf(0.5f * new_ehi * (v + 1.f)), 0, new_ehi - 1);
+        }
+    }
+}
+
+/**
+ * Calculate 3D coordinates on sphere for corresponding frame position in cubemap6x1 format.
+ *
+ * @param s filter context
+ * @param i horizontal position on frame [0, height)
+ * @param j vertical position on frame [0, width)
+ * @param width frame width
+ * @param height frame height
+ * @param vec coordinates on sphere
+ */
+static void cube6x1_to_xyz(const V360Context *s,
+                           int i, int j, int width, int height,
+                           float *vec)
+{
+    const float ew = width / 6.f;
+    const float eh = height;
+
+    const int face = floorf(i / ew);
+
+    const int u_shift = ceilf(ew * face);
+    const int ewi = ceilf(ew * (face + 1)) - u_shift;
+
+    const float uf = 2.f * (i - u_shift) / ewi - 1.f;
+    const float vf = 2.f *  j            / eh  - 1.f;
+
+    cube_to_xyz(s, uf, vf, face, vec);
+}
+
+/**
+ * Calculate frame position in cubemap6x1 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_cube6x1(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 ew = width / 6.f;
+    const float eh = height;
+    float uf, vf;
+    int ui, vi;
+    int ewi;
+    int i, j;
+    int direction, face;
+
+    xyz_to_cube(s, vec, &uf, &vf, &direction);
+
+    face = s->in_cubemap_face_order[direction];
+    ewi = ceilf(ew * (face + 1)) - ceilf(ew * face);
+
+    uf = 0.5f * ewi * (uf + 1.f);
+    vf = 0.5f * eh  * (vf + 1.f);
+
+    ui = floorf(uf);
+    vi = floorf(vf);
+
+    *du = uf - ui;
+    *dv = vf - vi;
+
+    for (i = -1; i < 3; i++) {
+        for (j = -1; j < 3; j++) {
+            float u, v;
+            int u_shift;
+            int new_ewi;
+
+            process_cube_coordinates(s, 2.f * (ui + j) / ewi - 1.f,
+                                        2.f * (vi + i) / eh  - 1.f,
+                                        direction, &u, &v, &face);
+            u_shift = ceilf(ew * face);
+            new_ewi = ceilf(ew * (face + 1)) - u_shift;
+
+            us[i + 1][j + 1] = u_shift + av_clip(roundf(0.5f * new_ewi * (u + 1.f)), 0, new_ewi - 1);
+            vs[i + 1][j + 1] =           av_clip(roundf(0.5f * eh      * (v + 1.f)), 0, eh      - 1);
+        }
+    }
+}
+
+/**
+ * Calculate 3D coordinates on sphere for corresponding frame position in equirectangular format.
+ *
+ * @param s filter context
+ * @param i horizontal position on frame [0, height)
+ * @param j vertical position on frame [0, width)
+ * @param width frame width
+ * @param height frame height
+ * @param vec coordinates on sphere
+ */
+static void equirect_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 = ((2.f * j) / 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;
+}
+
+/**
+ * Calculate frame position in equirectangular 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_equirect(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]);
+    const float theta = asinf(-vec[1]);
+    float uf, vf;
+    int ui, vi;
+    int i, j;
+
+    uf = (phi   / M_PI   + 1.f) * width  / 2.f;
+    vf = (theta / M_PI_2 + 1.f) * height / 2.f;
+    ui = floorf(uf);
+    vi = floorf(vf);
+
+    *du = uf - ui;
+    *dv = vf - vi;
+
+    for (i = -1; i < 3; i++) {
+        for (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);
+        }
+    }
+}
+
+/**
+ * Prepare data for processing equi-angular cubemap input format.
+ *
+ * @param ctx filter context
+
+ * @return error code
+ */
+static int prepare_eac_in(AVFilterContext *ctx)
+{
+    V360Context *s = ctx->priv;
+
+    s->in_cubemap_face_order[RIGHT] = TOP_RIGHT;
+    s->in_cubemap_face_order[LEFT]  = TOP_LEFT;
+    s->in_cubemap_face_order[UP]    = BOTTOM_RIGHT;
+    s->in_cubemap_face_order[DOWN]  = BOTTOM_LEFT;
+    s->in_cubemap_face_order[FRONT] = TOP_MIDDLE;
+    s->in_cubemap_face_order[BACK]  = BOTTOM_MIDDLE;
+
+    s->in_cubemap_face_rotation[TOP_LEFT]      = ROT_0;
+    s->in_cubemap_face_rotation[TOP_MIDDLE]    = ROT_0;
+    s->in_cubemap_face_rotation[TOP_RIGHT]     = ROT_0;
+    s->in_cubemap_face_rotation[BOTTOM_LEFT]   = ROT_270;
+    s->in_cubemap_face_rotation[BOTTOM_MIDDLE] = ROT_90;
+    s->in_cubemap_face_rotation[BOTTOM_RIGHT]  = ROT_270;
+
+    return 0;
+}
+
+/**
+ * Prepare data for processing equi-angular cubemap output format.
+ *
+ * @param ctx filter context
+ *
+ * @return error code
+ */
+static int prepare_eac_out(AVFilterContext *ctx)
+{
+    V360Context *s = ctx->priv;
+
+    s->out_cubemap_direction_order[TOP_LEFT]      = LEFT;
+    s->out_cubemap_direction_order[TOP_MIDDLE]    = FRONT;
+    s->out_cubemap_direction_order[TOP_RIGHT]     = RIGHT;
+    s->out_cubemap_direction_order[BOTTOM_LEFT]   = DOWN;
+    s->out_cubemap_direction_order[BOTTOM_MIDDLE] = BACK;
+    s->out_cubemap_direction_order[BOTTOM_RIGHT]  = UP;
+
+    s->out_cubemap_face_rotation[TOP_LEFT]      = ROT_0;
+    s->out_cubemap_face_rotation[TOP_MIDDLE]    = ROT_0;
+    s->out_cubemap_face_rotation[TOP_RIGHT]     = ROT_0;
+    s->out_cubemap_face_rotation[BOTTOM_LEFT]   = ROT_270;
+    s->out_cubemap_face_rotation[BOTTOM_MIDDLE] = ROT_90;
+    s->out_cubemap_face_rotation[BOTTOM_RIGHT]  = ROT_270;
+
+    return 0;
+}
+
+/**
+ * Calculate 3D coordinates on sphere for corresponding frame position in equi-angular cubemap format.
+ *
+ * @param s filter context
+ * @param i horizontal position on frame [0, height)
+ * @param j vertical position on frame [0, width)
+ * @param width frame width
+ * @param height frame height
+ * @param vec coordinates on sphere
+ */
+static void eac_to_xyz(const V360Context *s,
+                       int i, int j, int width, int height,
+                       float *vec)
+{
+    const float pixel_pad = 2;
+    const float u_pad = pixel_pad / width;
+    const float v_pad = pixel_pad / height;
+
+    int u_face, v_face, face;
+
+    float l_x, l_y, l_z;
+    float norm;
+
+    float uf = (float)i / width;
+    float vf = (float)j / height;
+
+    // EAC has 2-pixel padding on faces except between faces on the same row
+    // Padding pixels seems not to be stretched with tangent as regular pixels
+    // Formulas below approximate original padding as close as I could get experimentally
+
+    // Horizontal padding
+    uf = 3.f * (uf - u_pad) / (1.f - 2.f * u_pad);
+    if (uf < 0.f) {
+        u_face = 0;
+        uf -= 0.5f;
+    } else if (uf >= 3.f) {
+        u_face = 2;
+        uf -= 2.5f;
+    } else {
+        u_face = floorf(uf);
+        uf = fmodf(uf, 1.f) - 0.5f;
+    }
+
+    // Vertical padding
+    v_face = floorf(vf * 2.f);
+    vf = (vf - v_pad - 0.5f * v_face) / (0.5f - 2.f * v_pad) - 0.5f;
+
+    if (uf >= -0.5f && uf < 0.5f) {
+        uf = tanf(M_PI_2 * uf);
+    } else {
+        uf = 2.f * uf;
+    }
+    if (vf >= -0.5f && vf < 0.5f) {
+        vf = tanf(M_PI_2 * vf);
+    } else {
+        vf = 2.f * vf;
+    }
+
+    face = u_face + 3 * v_face;
+
+    switch (face) {
+    case TOP_LEFT:
+        l_x = -1.f;
+        l_y = -vf;
+        l_z = -uf;
+        break;
+    case TOP_MIDDLE:
+        l_x =  uf;
+        l_y = -vf;
+        l_z = -1.f;
+        break;
+    case TOP_RIGHT:
+        l_x =  1.f;
+        l_y = -vf;
+        l_z =  uf;
+        break;
+    case BOTTOM_LEFT:
+        l_x = -vf;
+        l_y = -1.f;
+        l_z =  uf;
+        break;
+    case BOTTOM_MIDDLE:
+        l_x = -vf;
+        l_y =  uf;
+        l_z =  1.f;
+        break;
+    case BOTTOM_RIGHT:
+        l_x = -vf;
+        l_y =  1.f;
+        l_z = -uf;
+        break;
+    }
+
+    norm = sqrtf(l_x * l_x + l_y * l_y + l_z * l_z);
+    vec[0] = l_x / norm;
+    vec[1] = l_y / norm;
+    vec[2] = l_z / norm;
+}
+
+/**
+ * Calculate frame position in equi-angular cubemap 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_eac(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 pixel_pad = 2;
+    const float u_pad = pixel_pad / width;
+    const float v_pad = pixel_pad / height;
+
+    float uf, vf;
+    int ui, vi;
+    int i, j;
+    int direction, face;
+    int u_face, v_face;
+
+    xyz_to_cube(s, vec, &uf, &vf, &direction);
+
+    face = s->in_cubemap_face_order[direction];
+    u_face = face % 3;
+    v_face = face / 3;
+
+    uf = M_2_PI * atanf(uf) + 0.5f;
+    vf = M_2_PI * atanf(vf) + 0.5f;
+
+    // These formulas are inversed from eac_to_xyz ones
+    uf = (uf + u_face) * (1.f - 2.f * u_pad) / 3.f + u_pad;
+    vf = vf * (0.5f - 2.f * v_pad) + v_pad + 0.5f * v_face;
+
+    uf *= width;
+    vf *= height;
+
+    ui = floorf(uf);
+    vi = floorf(vf);
+
+    *du = uf - ui;
+    *dv = vf - vi;
+
+    for (i = -1; i < 3; i++) {
+        for (j = -1; j < 3; j++) {
+            us[i + 1][j + 1] = av_clip(ui + j, 0, width  - 1);
+            vs[i + 1][j + 1] = av_clip(vi + i, 0, height - 1);
+        }
+    }
+}
+
+/**
+ * Prepare data for processing flat output format.
+ *
+ * @param ctx filter context
+ *
+ * @return error code
+ */
+static int prepare_flat_out(AVFilterContext *ctx)
+{
+    V360Context *s = ctx->priv;
+
+    const float h_angle = 0.5f * s->h_fov * M_PI / 180.f;
+    const float v_angle = 0.5f * s->v_fov * M_PI / 180.f;
+
+    const float sin_phi   = sinf(h_angle);
+    const float cos_phi   = cosf(h_angle);
+    const float sin_theta = sinf(v_angle);
+    const float cos_theta = cosf(v_angle);
+
+    s->flat_range[0] =  cos_theta * sin_phi;
+    s->flat_range[1] =  sin_theta;
+    s->flat_range[2] = -cos_theta * cos_phi;
+
+    return 0;
+}
+
+/**
+ * Calculate 3D coordinates on sphere for corresponding frame position in flat format.
+ *
+ * @param s filter context
+ * @param i horizontal position on frame [0, height)
+ * @param j vertical position on frame [0, width)
+ * @param width frame width
+ * @param height frame height
+ * @param vec coordinates on sphere
+ */
+static void flat_to_xyz(const V360Context *s,
+                        int i, int j, int width, int height,
+                        float *vec)
+{
+    const float l_x =  s->flat_range[0] * (2.f * i / width  - 1.f);
+    const float l_y = -s->flat_range[1] * (2.f * j / height - 1.f);
+    const float l_z =  s->flat_range[2];
+
+    const float norm = sqrtf(l_x * l_x + l_y * l_y + l_z * l_z);
+
+    vec[0] = l_x / norm;
+    vec[1] = l_y / norm;
+    vec[2] = l_z / norm;
+}
+
+/**
+ * Calculate rotation matrix for yaw/pitch/roll angles.
+ */
+static inline void calculate_rotation_matrix(float yaw, float pitch, float roll,
+                                             float rot_mat[3][3])
+{
+    const float yaw_rad   = yaw   * M_PI / 180.f;
+    const float pitch_rad = pitch * M_PI / 180.f;
+    const float roll_rad  = roll  * M_PI / 180.f;
+
+    const float sin_yaw   = sinf(-yaw_rad);
+    const float cos_yaw   = cosf(-yaw_rad);
+    const float sin_pitch = sinf(pitch_rad);
+    const float cos_pitch = cosf(pitch_rad);
+    const float sin_roll  = sinf(roll_rad);
+    const float cos_roll  = cosf(roll_rad);
+
+    rot_mat[0][0] = sin_yaw * sin_pitch * sin_roll + cos_yaw * cos_roll;
+    rot_mat[0][1] = sin_yaw * sin_pitch * cos_roll - cos_yaw * sin_roll;
+    rot_mat[0][2] = sin_yaw * cos_pitch;
+
+    rot_mat[1][0] = cos_pitch * sin_roll;
+    rot_mat[1][1] = cos_pitch * cos_roll;
+    rot_mat[1][2] = -sin_pitch;
+
+    rot_mat[2][0] = cos_yaw * sin_pitch * sin_roll - sin_yaw * cos_roll;
+    rot_mat[2][1] = cos_yaw * sin_pitch * cos_roll + sin_yaw * sin_roll;
+    rot_mat[2][2] = cos_yaw * cos_pitch;
+}
+
+/**
+ * Rotate vector with given rotation matrix.
+ *
+ * @param rot_mat rotation matrix
+ * @param vec vector
+ */
+static inline void rotate(const float rot_mat[3][3],
+                          float *vec)
+{
+    const float x_tmp = vec[0] * rot_mat[0][0] + vec[1] * rot_mat[0][1] + vec[2] * rot_mat[0][2];
+    const float y_tmp = vec[0] * rot_mat[1][0] + vec[1] * rot_mat[1][1] + vec[2] * rot_mat[1][2];
+    const float z_tmp = vec[0] * rot_mat[2][0] + vec[1] * rot_mat[2][1] + vec[2] * rot_mat[2][2];
+
+    vec[0] = x_tmp;
+    vec[1] = y_tmp;
+    vec[2] = z_tmp;
+}
+
+static inline void set_mirror_modifier(int h_flip, int v_flip, int d_flip,
+                                       float *modifier)
+{
+    modifier[0] = h_flip ? -1.f : 1.f;
+    modifier[1] = v_flip ? -1.f : 1.f;
+    modifier[2] = d_flip ? -1.f : 1.f;
+}
+
+static inline void mirror(const float *modifier,
+                          float *vec)
+{
+    vec[0] *= modifier[0];
+    vec[1] *= modifier[1];
+    vec[2] *= modifier[2];
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    AVFilterLink *inlink = ctx->inputs[0];
+    V360Context *s = ctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    const int depth = desc->comp[0].depth;
+    float remap_data_size = 0.f;
+    int sizeof_remap;
+    int err;
+    int p, h, w;
+    float hf, wf;
+    float mirror_modifier[3];
+    void (*in_transform)(const V360Context *s,
+                         const float *vec, int width, int height,
+                         uint16_t us[4][4], uint16_t vs[4][4], float *du, float *dv);
+    void (*out_transform)(const V360Context *s,
+                          int i, int j, int width, int height,
+                          float *vec);
+    void (*calculate_kernel)(float du, float dv, int shift, const XYRemap4 *r_tmp, void *r);
+    float rot_mat[3][3];
+
+    switch (s->interp) {
+    case NEAREST:
+        calculate_kernel = nearest_kernel;
+        s->remap_slice = depth <= 8 ? remap1_8bit_slice : remap1_16bit_slice;
+        sizeof_remap = sizeof(XYRemap1);
+        break;
+    case BILINEAR:
+        calculate_kernel = bilinear_kernel;
+        s->remap_slice = depth <= 8 ? remap2_8bit_slice : remap2_16bit_slice;
+        sizeof_remap = sizeof(XYRemap2);
+        break;
+    case BICUBIC:
+        calculate_kernel = bicubic_kernel;
+        s->remap_slice = depth <= 8 ? remap4_8bit_slice : remap4_16bit_slice;
+        sizeof_remap = sizeof(XYRemap4);
+        break;
+    case LANCZOS:
+        calculate_kernel = lanczos_kernel;
+        s->remap_slice = depth <= 8 ? remap4_8bit_slice : remap4_16bit_slice;
+        sizeof_remap = sizeof(XYRemap4);
+        break;
+    }
+
+    switch (s->in) {
+    case EQUIRECTANGULAR:
+        in_transform = xyz_to_equirect;
+        err = 0;
+        wf = inlink->w;
+        hf = inlink->h;
+        break;
+    case CUBEMAP_3_2:
+        in_transform = xyz_to_cube3x2;
+        err = prepare_cube_in(ctx);
+        wf = inlink->w / 3.f * 4.f;
+        hf = inlink->h;
+        break;
+    case CUBEMAP_6_1:
+        in_transform = xyz_to_cube6x1;
+        err = prepare_cube_in(ctx);
+        wf = inlink->w / 3.f * 2.f;
+        hf = inlink->h * 2.f;
+        break;
+    case EQUIANGULAR:
+        in_transform = xyz_to_eac;
+        err = prepare_eac_in(ctx);
+        wf = inlink->w;
+        hf = inlink->h / 9.f * 8.f;
+        break;
+    case FLAT:
+        av_log(ctx, AV_LOG_ERROR, "Flat format is not accepted as input.\n");
+        return AVERROR(EINVAL);
+    default:
+        av_log(ctx, AV_LOG_ERROR, "Specified input format is not handled.\n");
+        return AVERROR_BUG;
+    }
+
+    if (err != 0) {
+        return err;
+    }
+
+    switch (s->out) {
+    case EQUIRECTANGULAR:
+        out_transform = equirect_to_xyz;
+        err = 0;
+        w = roundf(wf);
+        h = roundf(hf);
+        break;
+    case CUBEMAP_3_2:
+        out_transform = cube3x2_to_xyz;
+        err = prepare_cube_out(ctx);
+        w = roundf(wf / 4.f * 3.f);
+        h = roundf(hf);
+        break;
+    case CUBEMAP_6_1:
+        out_transform = cube6x1_to_xyz;
+        err = prepare_cube_out(ctx);
+        w = roundf(wf / 2.f * 3.f);
+        h = roundf(hf / 2.f);
+        break;
+    case EQUIANGULAR:
+        out_transform = eac_to_xyz;
+        err = prepare_eac_out(ctx);
+        w = roundf(wf);
+        h = roundf(hf / 8.f * 9.f);
+        break;
+    case FLAT:
+        out_transform = flat_to_xyz;
+        err = prepare_flat_out(ctx);
+        w = roundf(wf * s->flat_range[0] / s->flat_range[1] / 2.f);
+        h = roundf(hf);
+        break;
+    default:
+        av_log(ctx, AV_LOG_ERROR, "Specified output format is not handled.\n");
+        return AVERROR_BUG;
+    }
+
+    if (err != 0) {
+        return err;
+    }
+
+    // Override resolution with user values if specified
+    if (s->width > 0 && s->height > 0) {
+        w = s->width;
+        h = s->height;
+    } else if (s->width > 0 || s->height > 0) {
+        av_log(ctx, AV_LOG_ERROR, "Both width and height values should be specified.\n");
+        return AVERROR(EINVAL);
+    }
+
+    s->planeheight[1] = s->planeheight[2] = FF_CEIL_RSHIFT(h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = h;
+    s->planewidth[1]  = s->planewidth[2] = FF_CEIL_RSHIFT(w, desc->log2_chroma_w);
+    s->planewidth[0]  = s->planewidth[3] = w;
+
+    outlink->h = h;
+    outlink->w = w;
+
+    s->inplaneheight[1] = s->inplaneheight[2] = FF_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->inplaneheight[0] = s->inplaneheight[3] = inlink->h;
+    s->inplanewidth[1]  = s->inplanewidth[2]  = FF_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
+    s->inplanewidth[0]  = s->inplanewidth[3]  = inlink->w;
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    for (p = 0; p < s->nb_planes; p++) {
+        remap_data_size += (float)s->planewidth[p] * s->planeheight[p] * sizeof_remap;
+    }
+
+    for (p = 0; p < s->nb_planes; p++) {
+        s->remap[p] = av_calloc(s->planewidth[p] * s->planeheight[p], sizeof_remap);
+        if (!s->remap[p]) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Not enough memory to allocate remap data. Need at least %.3f GiB.\n",
+                   remap_data_size / (1024 * 1024 * 1024));
+            return AVERROR(ENOMEM);
+        }
+    }
+
+    calculate_rotation_matrix(s->yaw, s->pitch, s->roll, rot_mat);
+    set_mirror_modifier(s->h_flip, s->v_flip, s->d_flip, mirror_modifier);
+
+    // Calculate remap data
+    for (p = 0; p < s->nb_planes; p++) {
+        const int width = s->planewidth[p];
+        const int height = s->planeheight[p];
+        const int in_width = s->inplanewidth[p];
+        const int in_height = s->inplaneheight[p];
+        void *r = s->remap[p];
+        float du, dv;
+        float vec[3];
+        XYRemap4 r_tmp;
+        int i, j;
+
+        for (i = 0; i < width; i++) {
+            for (j = 0; j < height; j++) {
+                out_transform(s, i, j, width, height, vec);
+                rotate(rot_mat, vec);
+                mirror(mirror_modifier, vec);
+                in_transform(s, vec, in_width, in_height, r_tmp.u, r_tmp.v, &du, &dv);
+                calculate_kernel(du, dv, j * width + i, &r_tmp, r);
+            }
+        }
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    V360Context *s = ctx->priv;
+    AVFrame *out;
+    ThreadData td;
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+
+    td.s = s;
+    td.in = in;
+    td.out = out;
+    td.nb_planes = s->nb_planes;
+
+    ctx->internal->execute(ctx, s->remap_slice, &td, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    V360Context *s = ctx->priv;
+    int p;
+
+    for (p = 0; p < s->nb_planes; p++)
+        av_freep(&s->remap[p]);
+}
+
+static const AVFilterPad inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_v360 = {
+    .name          = "v360",
+    .description   = NULL_IF_CONFIG_SMALL("Convert 360 projection of video."),
+    .priv_size     = sizeof(V360Context),
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = inputs,
+    .outputs       = outputs,
+    .priv_class    = &v360_class,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
+};