[FFmpeg-devel] [PATCH v2 1/3] avfilter: add v360 filter

Paul B Mahol onemda at gmail.com
Wed Aug 14 12:37:40 EEST 2019


On Wed, Aug 14, 2019 at 9:01 AM Li, Zhong <zhong.li at intel.com> wrote:

> > From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> > Of Eugene Lyapustin
> > Sent: Wednesday, August 14, 2019 9:14 AM
> > To: ffmpeg-devel at ffmpeg.org
> > Subject: [FFmpeg-devel] [PATCH v2 1/3] avfilter: add v360 filter
> >
> > Signed-off-by: Eugene Lyapustin <unishifft at gmail.com>
> > ---
> >  doc/filters.texi         |  137 +++
> >  libavfilter/Makefile     |    1 +
> >  libavfilter/allfilters.c |    1 +
> >  libavfilter/vf_v360.c    | 1847
> > ++++++++++++++++++++++++++++++++++++++
>
> Probably you also want to update the Changelog?
>

That is job for comitter.


>
> >  4 files changed, 1986 insertions(+)
> >  create mode 100644 libavfilter/vf_v360.c
> >
> > diff --git a/doc/filters.texi b/doc/filters.texi
> > index e081cdc7bc..6168a3502a 100644
> > --- a/doc/filters.texi
> > +++ b/doc/filters.texi
> > @@ -17879,6 +17879,143 @@ Force a constant quantization parameter. If
> > not set, the filter will use the QP
> >  from the video stream (if available).
> >  @end table
> >
> > + at section v360
> > +
> > +Convert 360 videos between various formats.
> > +
> > +The filter accepts the following options:
> > +
> > + at table @option
> > +
> > + at item input
> > + at item output
> > +Set format of the input/output video.
> > +
> > +Available formats:
> > +
> > + at table @samp
> > +
> > + at item e
> > +Equirectangular projection.
> > +
> > + at item c3x2
> > + at item c6x1
> > +Cubemap with 3x2/6x1 layout.
> > +
> > +Format specific options:
> > +
> > + at table @option
> > + at item in_forder
> > + at item out_forder
> > +Set order of faces for the input/output cubemap. Choose one direction
> for
> > each position.
> > +
> > +Designation of directions:
> > + at table @samp
> > + at item r
> > +right
> > + at item l
> > +left
> > + at item u
> > +up
> > + at item d
> > +down
> > + at item f
> > +forward
> > + at item b
> > +back
> > + at end table
> > +
> > +Default value is @b{@samp{rludfb}}.
> > +
> > + at item in_frot
> > + at item out_frot
> > +Set rotation of faces for the input/output cubemap. Choose one angle for
> > each position.
> > +
> > +Designation of angles:
> > + at table @samp
> > + at item 0
> > +0 degrees clockwise
> > + at item 1
> > +90 degrees clockwise
> > + at item 2
> > +180 degrees clockwise
> > + at item 4
> > +270 degrees clockwise
> > + at end table
> > +
> > +Default value is @b{@samp{000000}}.
> > + at end table
> > +
> > + at item eac
> > +Equi-Angular Cubemap.
> > +
> > + at item flat
> > +Regular video. @i{(output only)}
> > +
> > +Format specific options:
> > + at table @option
> > + at item h_fov
> > + at item v_fov
> > +Set horizontal/vertical field of view. Values in degrees.
> > + at end table
> > + at end table
> > +
> > + at item interp
> > +Set interpolation method.@*
> > + at i{Note: more complex interpolation methods require much more memory
> > to run.}
> > +
> > +Available methods:
> > +
> > + at table @samp
> > + at item near
> > + at item nearest
> > +Nearest neighbour.
> > + at item line
> > + at item linear
> > +Bilinear interpolation.
> > + at item cube
> > + at item cubic
> > +Bicubic interpolation.
> > + at item lanc
> > + at item lanczos
> > +Lanczos interpolation.
> > + at end table
> > +
> > +Default value is @b{@samp{line}}.
> > +
> > + at item w
> > + at item h
> > +Set the output video resolution.
> > +
> > +Default resolution depends on formats.
> > +
> > + at item yaw
> > + at item pitch
> > + at item roll
> > +Set rotation for the output video. Values in degrees.
> > +
> > + at item hflip
> > + at item vflip
> > + at item dflip
> > +Flip the output video horizontally/vertically/in-depth. Boolean values.
> > +
> > + at end table
> > +
> > + at subsection Examples
> > +
> > + at itemize
> > + at item
> > +Convert equirectangular video to cubemap with 3x2 layout using bicubic
> > interpolation:
> > + at example
> > +ffmpeg -i input.mkv -vf v360=e:c3x2:cubic output.mkv
> > + at end example
> > + at item
> > +Extract back view of Equi-Angular Cubemap:
> > + at example
> > +ffmpeg -i input.mkv -vf v360=eac:flat:yaw=180 output.mkv
> > + at end example
> > + at end itemize
> > +
> >  @section vaguedenoiser
> >
> >  Apply a wavelet based denoiser.
> > diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> > index efc7bbb153..345f7c95cd 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 abd726d616..5799fb4b3c 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 0000000000..5c377827b0
> > --- /dev/null
> > +++ b/libavfilter/vf_v360.c
> > @@ -0,0 +1,1847 @@
> > +/*
> > + * 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;
> > +    }
> > +}
>
> "case” should be kept alignment as "swicth", remove the blanks.
>
> > +/**
> > + * 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++) {
>
> Moving "int face" as the beginning of function can avoid int twice.
>

Please no, I like current style.


>
> > +        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++) {
>
> Same.
>
> > +        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);
> > +    }
> > +
> > +    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;
> > +    }
> > +
> > +    if (err != 0) {
> > +        return err;
> > +    }
> > +
> > +    if (s->width > 0 && s->height > 0) {
> > +        w = s->width;
> > +        h = s->height;
> > +    }
>
> If s->width/height are checked, should handle the case of no ture,
> Else w/h may be used but not initialized.
>

Please try more hard to write english. I do not understand what is typed
above.


>
> > +    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,
> > +};
> > --
> > 2.22.0
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