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ffmpeg/libavfilter/vf_ssim360.c

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/**
* Copyright (c) 2015-2021, Facebook, Inc.
* All rights reserved.
*
* 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
*/
/* Computes the Structural Similarity Metric between two 360 video streams.
* original SSIM algorithm:
* Z. Wang, A. C. Bovik, H. R. Sheikh and E. P. Simoncelli,
* "Image quality assessment: From error visibility to structural similarity,"
* IEEE Transactions on Image Processing, vol. 13, no. 4, pp. 600-612, Apr. 2004.
*
* To improve speed, this implementation uses the standard approximation of
* overlapped 8x8 block sums, rather than the original gaussian weights.
*
* To address warping from 360 projections for videos with same
* projection and resolution, the 8x8 blocks sampled are weighted by
* their location in the image.
*
* To apply SSIM across projections and video sizes, we render the video on to
* a flat "tape" from which the 8x8 are selected and compared.
*/
/*
* @file
* Caculate the SSIM between two input 360 videos.
*/
#include <math.h>
#include "libavutil/avstring.h"
#include "libavutil/file_open.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "drawutils.h"
#include "internal.h"
#include "framesync.h"
#define RIGHT 0
#define LEFT 1
#define TOP 2
#define BOTTOM 3
#define FRONT 4
#define BACK 5
#define DEFAULT_HEATMAP_W 32
#define DEFAULT_HEATMAP_H 16
#define M_PI_F ((float)M_PI)
#define M_PI_2_F ((float)M_PI_2)
#define M_PI_4_F ((float)M_PI_4)
#define M_SQRT2_F ((float)M_SQRT2)
#define DEFAULT_EXPANSION_COEF 1.01f
#define BARREL_THETA_RANGE (DEFAULT_EXPANSION_COEF * 2.0f * M_PI_F)
#define BARREL_PHI_RANGE (DEFAULT_EXPANSION_COEF * M_PI_2_F)
// Use fixed-point with 16 bit precision for fast bilinear math
#define FIXED_POINT_PRECISION 16
// Use 1MB per channel for the histogram to get 5-digit precise SSIM value
#define SSIM360_HIST_SIZE 131072
// The last number is a marker < 0 to mark end of list
static const double PERCENTILE_LIST[] = {
1.0, 0.9, 0.8, 0.7, 0.6,
0.5, 0.4, 0.3, 0.2, 0.1, 0, -1
};
typedef enum StereoFormat {
STEREO_FORMAT_TB,
STEREO_FORMAT_LR,
STEREO_FORMAT_MONO,
STEREO_FORMAT_N
} StereoFormat;
typedef enum Projection {
PROJECTION_CUBEMAP32,
PROJECTION_CUBEMAP23,
PROJECTION_BARREL,
PROJECTION_BARREL_SPLIT,
PROJECTION_EQUIRECT,
PROJECTION_N
} Projection;
typedef struct Map2D {
int w, h;
double *value;
} Map2D;
typedef struct HeatmapList {
Map2D map;
struct HeatmapList *next;
} HeatmapList;
typedef struct SampleParams {
int stride;
int planewidth;
int planeheight;
int x_image_offset;
int y_image_offset;
int x_image_range;
int y_image_range;
int projection;
float expand_coef;
} SampleParams;
typedef struct BilinearMap {
// Indices to the 4 samples to compute bilinear
int tli;
int tri;
int bli;
int bri;
// Fixed point factors with which the above 4 sample vector's
// dot product needs to be computed for the final bilinear value
int tlf;
int trf;
int blf;
int brf;
} BilinearMap;
typedef struct SSIM360Context {
const AVClass *class;
FFFrameSync fs;
// Stats file configuration
FILE *stats_file;
char *stats_file_str;
// Component properties
int nb_components;
double coefs[4];
char comps[4];
int max;
// Channel configuration & properties
int compute_chroma;
int is_rgb;
uint8_t rgba_map[4];
// Standard SSIM computation configuration & workspace
uint64_t frame_skip_ratio;
int *temp;
uint64_t nb_ssim_frames;
uint64_t nb_net_frames;
double ssim360[4], ssim360_total;
double *ssim360_hist[4];
double ssim360_hist_net[4];
double ssim360_percentile_sum[4][256];
// 360 projection configuration & workspace
int ref_projection;
int main_projection;
int ref_stereo_format;
int main_stereo_format;
float ref_pad;
float main_pad;
int use_tape;
char *heatmap_str;
int default_heatmap_w;
int default_heatmap_h;
Map2D density;
HeatmapList *heatmaps;
int ref_planewidth[4];
int ref_planeheight[4];
int main_planewidth[4];
int main_planeheight[4];
int tape_length[4];
BilinearMap *ref_tape_map[4][2];
BilinearMap *main_tape_map[4][2];
float angular_resolution[4][2];
double (*ssim360_plane)(
uint8_t *main, int main_stride,
uint8_t *ref, int ref_stride,
int width, int height, void *temp,
int max, Map2D density);
} SSIM360Context;
#define OFFSET(x) offsetof(SSIM360Context, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption ssim360_options[] = {
{ "stats_file", "Set file where to store per-frame difference information",
OFFSET(stats_file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
{ "f", "Set file where to store per-frame difference information",
OFFSET(stats_file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
{ "compute_chroma",
"Specifies if non-luma channels must be computed",
OFFSET(compute_chroma), AV_OPT_TYPE_INT, {.i64 = 1},
0, 1, .flags = FLAGS },
{ "frame_skip_ratio",
"Specifies the number of frames to be skipped from evaluation, for every evaluated frame",
OFFSET(frame_skip_ratio), AV_OPT_TYPE_INT, {.i64 = 0},
0, 1000000, .flags = FLAGS },
{ "ref_projection", "projection of the reference video",
OFFSET(ref_projection), AV_OPT_TYPE_INT, {.i64 = PROJECTION_EQUIRECT},
0, PROJECTION_N - 1, .flags = FLAGS, .unit = "projection" },
{ "e", "equirectangular", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_EQUIRECT}, 0, 0, FLAGS, .unit = "projection" },
{ "equirect", "equirectangular", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_EQUIRECT}, 0, 0, FLAGS, .unit = "projection" },
{ "c3x2", "cubemap 3x2", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_CUBEMAP32}, 0, 0, FLAGS, .unit = "projection" },
{ "c2x3", "cubemap 2x3", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_CUBEMAP23}, 0, 0, FLAGS, .unit = "projection" },
{ "barrel", "barrel facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_BARREL}, 0, 0, FLAGS, .unit = "projection" },
{ "barrelsplit", "barrel split facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_BARREL_SPLIT}, 0, 0, FLAGS, .unit = "projection" },
{ "main_projection", "projection of the main video",
OFFSET(main_projection), AV_OPT_TYPE_INT, {.i64 = PROJECTION_N},
0, PROJECTION_N, .flags = FLAGS, .unit = "projection" },
{ "ref_stereo", "stereo format of the reference video",
OFFSET(ref_stereo_format), AV_OPT_TYPE_INT, {.i64 = STEREO_FORMAT_MONO},
0, STEREO_FORMAT_N - 1, .flags = FLAGS, .unit = "stereo_format" },
{ "mono", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = STEREO_FORMAT_MONO }, 0, 0, FLAGS, .unit = "stereo_format" },
{ "tb", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = STEREO_FORMAT_TB }, 0, 0, FLAGS, .unit = "stereo_format" },
{ "lr", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = STEREO_FORMAT_LR }, 0, 0, FLAGS, .unit = "stereo_format" },
{ "main_stereo", "stereo format of main video",
OFFSET(main_stereo_format), AV_OPT_TYPE_INT, {.i64 = STEREO_FORMAT_N},
0, STEREO_FORMAT_N, .flags = FLAGS, .unit = "stereo_format" },
{ "ref_pad",
"Expansion (padding) coefficient for each cube face of the reference video",
OFFSET(ref_pad), AV_OPT_TYPE_FLOAT, {.dbl = .0f}, 0, 10, .flags = FLAGS },
{ "main_pad",
"Expansion (padding) coeffiecient for each cube face of the main video",
OFFSET(main_pad), AV_OPT_TYPE_FLOAT, {.dbl = .0f}, 0, 10, .flags = FLAGS },
{ "use_tape",
"Specifies if the tape based SSIM 360 algorithm must be used independent of the input video types",
OFFSET(use_tape), AV_OPT_TYPE_INT, {.i64 = 0},
0, 1, .flags = FLAGS },
{ "heatmap_str",
"Heatmap data for view-based evaluation. For heatmap file format, please refer to EntSphericalVideoHeatmapData.",
OFFSET(heatmap_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, .flags = FLAGS },
{ "default_heatmap_width",
"Default heatmap dimension. Will be used when dimension is not specified in heatmap data.",
OFFSET(default_heatmap_w), AV_OPT_TYPE_INT, {.i64 = 32}, 1, 4096, .flags = FLAGS },
{ "default_heatmap_height",
"Default heatmap dimension. Will be used when dimension is not specified in heatmap data.",
OFFSET(default_heatmap_h), AV_OPT_TYPE_INT, {.i64 = 16}, 1, 4096, .flags = FLAGS },
{ NULL }
};
FRAMESYNC_DEFINE_CLASS(ssim360, SSIM360Context, fs);
static void set_meta(AVDictionary **metadata, const char *key, char comp, float d)
{
char value[128];
snprintf(value, sizeof(value), "%0.2f", d);
if (comp) {
char key2[128];
snprintf(key2, sizeof(key2), "%s%c", key, comp);
av_dict_set(metadata, key2, value, 0);
} else {
av_dict_set(metadata, key, value, 0);
}
}
static void map_uninit(Map2D *map)
{
av_freep(&map->value);
}
static int map_init(Map2D *map, int w, int h)
{
map->value = av_calloc(h * w, sizeof(*map->value));
if (!map->value)
return AVERROR(ENOMEM);
map->h = h;
map->w = w;
return 0;
}
static void map_list_free(HeatmapList **pl)
{
HeatmapList *l = *pl;
while (l) {
HeatmapList *next = l->next;
map_uninit(&l->map);
av_freep(&l);
l = next;
}
*pl = NULL;
}
static int map_alloc(HeatmapList **pl, int w, int h)
{
HeatmapList *l;
int ret;
l = av_mallocz(sizeof(*l));
if (!l)
return AVERROR(ENOMEM);
ret = map_init(&l->map, w, h);
if (ret < 0) {
av_freep(&l);
return ret;
}
*pl = l;
return 0;
}
static void
ssim360_4x4xn_16bit(const uint8_t *main8, ptrdiff_t main_stride,
const uint8_t *ref8, ptrdiff_t ref_stride,
int64_t (*sums)[4], int width)
{
const uint16_t *main16 = (const uint16_t *)main8;
const uint16_t *ref16 = (const uint16_t *)ref8;
main_stride >>= 1;
ref_stride >>= 1;
for (int z = 0; z < width; z++) {
uint64_t s1 = 0, s2 = 0, ss = 0, s12 = 0;
for (int y = 0; y < 4; y++) {
for (int x = 0; x < 4; x++) {
unsigned a = main16[x + y * main_stride];
unsigned b = ref16[x + y * ref_stride];
s1 += a;
s2 += b;
ss += a*a;
ss += b*b;
s12 += a*b;
}
}
sums[z][0] = s1;
sums[z][1] = s2;
sums[z][2] = ss;
sums[z][3] = s12;
main16 += 4;
ref16 += 4;
}
}
static void
ssim360_4x4xn_8bit(const uint8_t *main, ptrdiff_t main_stride,
const uint8_t *ref, ptrdiff_t ref_stride,
int (*sums)[4], int width)
{
for (int z = 0; z < width; z++) {
uint32_t s1 = 0, s2 = 0, ss = 0, s12 = 0;
for (int y = 0; y < 4; y++) {
for (int x = 0; x < 4; x++) {
int a = main[x + y * main_stride];
int b = ref[x + y * ref_stride];
s1 += a;
s2 += b;
ss += a*a;
ss += b*b;
s12 += a*b;
}
}
sums[z][0] = s1;
sums[z][1] = s2;
sums[z][2] = ss;
sums[z][3] = s12;
main += 4;
ref += 4;
}
}
static float ssim360_end1x(int64_t s1, int64_t s2, int64_t ss, int64_t s12, int max)
{
int64_t ssim_c1 = (int64_t)(.01 * .01 * max * max * 64 + .5);
int64_t ssim_c2 = (int64_t)(.03 * .03 * max * max * 64 * 63 + .5);
int64_t fs1 = s1;
int64_t fs2 = s2;
int64_t fss = ss;
int64_t fs12 = s12;
int64_t vars = fss * 64 - fs1 * fs1 - fs2 * fs2;
int64_t covar = fs12 * 64 - fs1 * fs2;
return (float)(2 * fs1 * fs2 + ssim_c1) * (float)(2 * covar + ssim_c2)
/ ((float)(fs1 * fs1 + fs2 * fs2 + ssim_c1) * (float)(vars + ssim_c2));
}
static float ssim360_end1(int s1, int s2, int ss, int s12)
{
static const int ssim_c1 = (int)(.01*.01*255*255*64 + .5);
static const int ssim_c2 = (int)(.03*.03*255*255*64*63 + .5);
int fs1 = s1;
int fs2 = s2;
int fss = ss;
int fs12 = s12;
int vars = fss * 64 - fs1 * fs1 - fs2 * fs2;
int covar = fs12 * 64 - fs1 * fs2;
return (float)(2 * fs1 * fs2 + ssim_c1) * (float)(2 * covar + ssim_c2)
/ ((float)(fs1 * fs1 + fs2 * fs2 + ssim_c1) * (float)(vars + ssim_c2));
}
static double
ssim360_endn_16bit(const int64_t (*sum0)[4], const int64_t (*sum1)[4],
int width, int max,
double *density_map, int map_width, double *total_weight)
{
double ssim360 = 0.0, weight;
for (int i = 0; i < width; i++) {
weight = density_map ? density_map[(int) ((0.5 + i) / width * map_width)] : 1.0;
ssim360 += weight * ssim360_end1x(
sum0[i][0] + sum0[i + 1][0] + sum1[i][0] + sum1[i + 1][0],
sum0[i][1] + sum0[i + 1][1] + sum1[i][1] + sum1[i + 1][1],
sum0[i][2] + sum0[i + 1][2] + sum1[i][2] + sum1[i + 1][2],
sum0[i][3] + sum0[i + 1][3] + sum1[i][3] + sum1[i + 1][3],
max);
*total_weight += weight;
}
return ssim360;
}
static double
ssim360_endn_8bit(const int (*sum0)[4], const int (*sum1)[4], int width,
double *density_map, int map_width, double *total_weight)
{
double ssim360 = 0.0, weight;
for (int i = 0; i < width; i++) {
weight = density_map ? density_map[(int) ((0.5 + i) / width * map_width)] : 1.0;
ssim360 += weight * ssim360_end1(
sum0[i][0] + sum0[i + 1][0] + sum1[i][0] + sum1[i + 1][0],
sum0[i][1] + sum0[i + 1][1] + sum1[i][1] + sum1[i + 1][1],
sum0[i][2] + sum0[i + 1][2] + sum1[i][2] + sum1[i + 1][2],
sum0[i][3] + sum0[i + 1][3] + sum1[i][3] + sum1[i + 1][3]);
*total_weight += weight;
}
return ssim360;
}
static double
ssim360_plane_16bit(uint8_t *main, int main_stride,
uint8_t *ref, int ref_stride,
int width, int height, void *temp,
int max, Map2D density)
{
int z = 0;
double ssim360 = 0.0;
int64_t (*sum0)[4] = temp;
int64_t (*sum1)[4] = sum0 + (width >> 2) + 3;
double total_weight = 0.0;
width >>= 2;
height >>= 2;
for (int y = 1; y < height; y++) {
for (; z <= y; z++) {
FFSWAP(void*, sum0, sum1);
ssim360_4x4xn_16bit(&main[4 * z * main_stride], main_stride,
&ref[4 * z * ref_stride], ref_stride,
sum0, width);
}
ssim360 += ssim360_endn_16bit(
(const int64_t (*)[4])sum0, (const int64_t (*)[4])sum1,
width - 1, max,
density.value ? density.value + density.w * ((int) ((z - 1.0) / height * density.h)) : NULL,
density.w, &total_weight);
}
return (double) (ssim360 / total_weight);
}
static double
ssim360_plane_8bit(uint8_t *main, int main_stride,
uint8_t *ref, int ref_stride,
int width, int height, void *temp,
int max, Map2D density)
{
int z = 0;
double ssim360 = 0.0;
int (*sum0)[4] = temp;
int (*sum1)[4] = sum0 + (width >> 2) + 3;
double total_weight = 0.0;
width >>= 2;
height >>= 2;
for (int y = 1; y < height; y++) {
for (; z <= y; z++) {
FFSWAP(void*, sum0, sum1);
ssim360_4x4xn_8bit(
&main[4 * z * main_stride], main_stride,
&ref[4 * z * ref_stride], ref_stride,
sum0, width);
}
ssim360 += ssim360_endn_8bit(
(const int (*)[4])sum0, (const int (*)[4])sum1, width - 1,
density.value ? density.value + density.w * ((int) ((z - 1.0) / height * density.h)) : NULL,
density.w, &total_weight);
}
return (double) (ssim360 / total_weight);
}
static double ssim360_db(double ssim360, double weight)
{
return 10 * log10(weight / (weight - ssim360));
}
static int get_bilinear_sample(const uint8_t *data, BilinearMap *m, int max_value)
{
static const int fixed_point_half = 1 << (FIXED_POINT_PRECISION - 1);
static const int inv_byte_mask = UINT_MAX << 8;
int tl, tr, bl, br, v;
if (max_value & inv_byte_mask) {
uint16_t *data16 = (uint16_t *)data;
tl = data16[m->tli];
tr = data16[m->tri];
bl = data16[m->bli];
br = data16[m->bri];
} else {
tl = data[m->tli];
tr = data[m->tri];
bl = data[m->bli];
br = data[m->bri];
}
v = m->tlf * tl +
m->trf * tr +
m->blf * bl +
m->brf * br;
// Round by half, and revert the fixed-point offset
return ((v + fixed_point_half) >> FIXED_POINT_PRECISION) & max_value;
}
static void
ssim360_4x4x2_tape(const uint8_t *main, BilinearMap *main_maps,
const uint8_t *ref, BilinearMap *ref_maps,
int offset_y, int max_value, int (*sums)[4])
{
int offset_x = 0;
// Two blocks along the width
for (int z = 0; z < 2; z++) {
int s1 = 0, s2 = 0, ss = 0, s12 = 0;
// 4 pixel block from (offset_x, offset_y)
for (int y = offset_y; y < offset_y + 4; y++) {
int y_stride = y << 3;
for (int x = offset_x; x < offset_x + 4; x++) {
int map_index = x + y_stride;
int a = get_bilinear_sample(main, main_maps + map_index, max_value);
int b = get_bilinear_sample(ref, ref_maps + map_index, max_value);
s1 += a;
s2 += b;
ss += a*a;
ss += b*b;
s12 += a*b;
}
}
sums[z][0] = s1;
sums[z][1] = s2;
sums[z][2] = ss;
sums[z][3] = s12;
offset_x += 4;
}
}
static float get_radius_between_negative_and_positive_pi(float theta)
{
int floor_theta_by_2pi, floor_theta_by_pi;
// Convert theta to range [0, 2*pi]
floor_theta_by_2pi = (int)(theta / (2.0f * M_PI_F)) - (theta < 0.0f);
theta -= 2.0f * M_PI_F * floor_theta_by_2pi;
// Convert theta to range [-pi, pi]
floor_theta_by_pi = theta / M_PI_F;
theta -= 2.0f * M_PI_F * floor_theta_by_pi;
return FFMIN(M_PI_F, FFMAX(-M_PI_F, theta));
}
static float get_heat(HeatmapList *heatmaps, float angular_resoluation, float norm_tape_pos)
{
float pitch, yaw, norm_pitch, norm_yaw;
int w, h;
if (!heatmaps)
return 1.0f;
pitch = asinf(norm_tape_pos*2);
yaw = M_PI_2_F * pitch / angular_resoluation;
yaw = get_radius_between_negative_and_positive_pi(yaw);
// normalize into [0,1]
norm_pitch = 1.0f - (pitch / M_PI_F + 0.5f);
norm_yaw = yaw / 2.0f / M_PI_F + 0.5f;
// get heat on map
w = FFMIN(heatmaps->map.w - 1, FFMAX(0, heatmaps->map.w * norm_yaw));
h = FFMIN(heatmaps->map.h - 1, FFMAX(0, heatmaps->map.h * norm_pitch));
return heatmaps->map.value[h * heatmaps->map.w + w];
}
static double
ssim360_tape(uint8_t *main, BilinearMap *main_maps,
uint8_t *ref, BilinearMap *ref_maps,
int tape_length, int max_value, void *temp,
double *ssim360_hist, double *ssim360_hist_net,
float angular_resolution, HeatmapList *heatmaps)
{
int horizontal_block_count = 2;
int vertical_block_count = tape_length >> 2;
int z = 0, y;
// Since the tape will be very long and we need to average over all 8x8 blocks, use double
double ssim360 = 0.0;
double sum_weight = 0.0;
int (*sum0)[4] = temp;
int (*sum1)[4] = sum0 + horizontal_block_count + 3;
for (y = 1; y < vertical_block_count; y++) {
int fs1, fs2, fss, fs12, hist_index;
float norm_tape_pos, weight;
double sample_ssim360;
for (; z <= y; z++) {
FFSWAP(void*, sum0, sum1);
ssim360_4x4x2_tape(main, main_maps, ref, ref_maps, z*4, max_value, sum0);
}
// Given we have only one 8x8 block, following sums fit within 26 bits even for 10bit videos
fs1 = sum0[0][0] + sum0[1][0] + sum1[0][0] + sum1[1][0];
fs2 = sum0[0][1] + sum0[1][1] + sum1[0][1] + sum1[1][1];
fss = sum0[0][2] + sum0[1][2] + sum1[0][2] + sum1[1][2];
fs12 = sum0[0][3] + sum0[1][3] + sum1[0][3] + sum1[1][3];
if (max_value > 255) {
// Since we need high precision to multiply fss / fs12 by 64, use double
double ssim_c1_d = .01*.01*64*max_value*max_value;
double ssim_c2_d = .03*.03*64*63*max_value*max_value;
double vars = 64. * fss - 1. * fs1 * fs1 - 1. * fs2 * fs2;
double covar = 64. * fs12 - 1.*fs1 * fs2;
sample_ssim360 = (2. * fs1 * fs2 + ssim_c1_d) * (2. * covar + ssim_c2_d)
/ ((1. * fs1 * fs1 + 1. * fs2 * fs2 + ssim_c1_d) * (1. * vars + ssim_c2_d));
} else {
static const int ssim_c1 = (int)(.01*.01*255*255*64 + .5);
static const int ssim_c2 = (int)(.03*.03*255*255*64*63 + .5);
int vars = fss * 64 - fs1 * fs1 - fs2 * fs2;
int covar = fs12 * 64 - fs1 * fs2;
sample_ssim360 = (double)(2 * fs1 * fs2 + ssim_c1) * (double)(2 * covar + ssim_c2)
/ ((double)(fs1 * fs1 + fs2 * fs2 + ssim_c1) * (double)(vars + ssim_c2));
}
hist_index = (int)(sample_ssim360 * ((double)SSIM360_HIST_SIZE - .5));
hist_index = av_clip(hist_index, 0, SSIM360_HIST_SIZE - 1);
norm_tape_pos = (y - 0.5f) / (vertical_block_count - 1.0f) - 0.5f;
// weight from an input heatmap if available, otherwise weight = 1.0
weight = get_heat(heatmaps, angular_resolution, norm_tape_pos);
ssim360_hist[hist_index] += weight;
*ssim360_hist_net += weight;
ssim360 += (sample_ssim360 * weight);
sum_weight += weight;
}
return ssim360 / sum_weight;
}
static void compute_bilinear_map(SampleParams *p, BilinearMap *m, float x, float y)
{
float fixed_point_scale = (float)(1 << FIXED_POINT_PRECISION);
// All operations in here will fit in the 22 bit mantissa of floating point,
// since the fixed point precision is well under 22 bits
float x_image = av_clipf(x * p->x_image_range, 0, p->x_image_range) + p->x_image_offset;
float y_image = av_clipf(y * p->y_image_range, 0, p->y_image_range) + p->y_image_offset;
int x_floor = x_image;
int y_floor = y_image;
float x_diff = x_image - x_floor;
float y_diff = y_image - y_floor;
int x_ceil = x_floor + (x_diff > 1e-6);
int y_ceil = y_floor + (y_diff > 1e-6);
float x_inv_diff = 1.0f - x_diff;
float y_inv_diff = 1.0f - y_diff;
// Indices of the 4 samples from source frame
m->tli = x_floor + y_floor * p->stride;
m->tri = x_ceil + y_floor * p->stride;
m->bli = x_floor + y_ceil * p->stride;
m->bri = x_ceil + y_ceil * p->stride;
// Scale to be applied to each of the 4 samples from source frame
m->tlf = x_inv_diff * y_inv_diff * fixed_point_scale;
m->trf = x_diff * y_inv_diff * fixed_point_scale;
m->blf = x_inv_diff * y_diff * fixed_point_scale;
m->brf = x_diff * y_diff * fixed_point_scale;
}
static void get_equirect_map(float phi, float theta, float *x, float *y)
{
*x = 0.5f + theta / (2.0f * M_PI_F);
// y increases downwards
*y = 0.5f - phi / M_PI_F;
}
static void get_barrel_map(float phi, float theta, float *x, float *y)
{
float abs_phi = FFABS(phi);
if (abs_phi <= M_PI_4_F) {
// Equirect region
*x = 0.8f * (0.5f + theta / BARREL_THETA_RANGE);
// y increases downwards
*y = 0.5f - phi / BARREL_PHI_RANGE;
} else {
// Radial ratio on a unit circle = cot(abs_phi) / (expansion_cefficient).
// Using cos(abs_phi)/sin(abs_phi) explicitly to avoid division by zero
float radial_ratio = cosf(abs_phi) / (sinf(abs_phi) * DEFAULT_EXPANSION_COEF);
float circle_x = radial_ratio * sinf(theta);
float circle_y = radial_ratio * cosf(theta);
float offset_y = 0.25f;
if (phi < 0) {
// Bottom circle: theta increases clockwise, and front is upward
circle_y *= -1.0f;
offset_y += 0.5f;
}
*x = 0.8f + 0.1f * (1.0f + circle_x);
*y = offset_y + 0.25f * circle_y;
}
}
static void get_barrel_split_map(float phi, float theta, float expand_coef, float *x, float *y)
{
float abs_phi = FFABS(phi);
// Front Face [-PI/2, PI/2] -> [0,1].
// Back Face [PI/2, PI] and [-PI, -PI/2] -> [1, 2]
float radian_pi_theta = theta / M_PI_F + 0.5f;
int vFace;
if (radian_pi_theta < 0.0f)
radian_pi_theta += 2.0f;
// Front face at top (= 0), back face at bottom (= 1).
vFace = radian_pi_theta >= 1.0f;
if (abs_phi <= M_PI_4_F) {
// Equirect region
*x = 2.0f / 3.0f * (0.5f + (radian_pi_theta - vFace - 0.5f) / expand_coef);
// y increases downwards
*y = 0.25f + 0.5f * vFace - phi / (M_PI_F * expand_coef);
} else {
// Radial ratio on a unit circle = cot(abs_phi) / (expansion_cefficient).
// Using cos(abs_phi)/sin(abs_phi) explicitly to avoid division by zero
float radial_ratio = cosf(abs_phi) / (sinf(abs_phi) * expand_coef);
float circle_x = radial_ratio * sinf(theta);
float circle_y = radial_ratio * cosf(theta);
float offset_y = 0.25f;
if (vFace == 1) {
// Back Face: Flip
circle_x *= -1.0f;
circle_y = (circle_y >= 0.0f) ? (1 - circle_y) : (-1 - circle_y);
offset_y += 0.5f;
// Bottom circle: theta increases clockwise
if (phi < 0)
circle_y *= -1.0f;
} else {
// Front Face
// Bottom circle: theta increases clockwise
if (phi < 0)
circle_y *= -1.0f;
}
*x = 2.0f / 3.0f + 0.5f / 3.0f * (1.0f + circle_x);
*y = offset_y + 0.25f * circle_y / expand_coef; // y direction of expand_coeff (margin)
}
}
// Returns cube face, and provided face_x & face_y will range from [0, 1]
static int get_cubemap_face_map(float axis_vec_x, float axis_vec_y, float axis_vec_z, float *face_x, float *face_y)
{
// To check if phi, theta hits the top / bottom faces, we check the hit point of
// the axis vector on planes y = 1 and y = -1, and see if x & z are within [-1, 1]
// 0.577 < 1 / sqrt(3), which is less than the smallest sin(phi) falling on top/bottom faces
// This angle check will save computation from unnecessarily checking the top/bottom faces
if (FFABS(axis_vec_y) > 0.577f) {
float x_hit = axis_vec_x / FFABS(axis_vec_y);
float z_hit = axis_vec_z / axis_vec_y;
if (FFABS(x_hit) <= 1.f && FFABS(z_hit) <= 1.f) {
*face_x = x_hit;
// y increases downwards
*face_y = z_hit;
return axis_vec_y > 0 ? TOP : BOTTOM;
}
}
// Check for left / right faces
if (FFABS(axis_vec_x) > 0.577f) {
float z_hit = -axis_vec_z / axis_vec_x;
float y_hit = axis_vec_y / FFABS(axis_vec_x);
if (FFABS(z_hit) <= 1.f && FFABS(y_hit) <= 1.f) {
*face_x = z_hit;
// y increases downwards
*face_y = -y_hit;
return axis_vec_x > 0 ? RIGHT : LEFT;
}
}
// Front / back faces
*face_x = axis_vec_x / axis_vec_z;
// y increases downwards
*face_y = -axis_vec_y / FFABS(axis_vec_z);
return axis_vec_z > 0 ? FRONT : BACK;
}
static void get_cubemap32_map(float phi, float theta, float *x, float *y)
{
// face_projection_map maps each cube face to an index representing the face on the projection
// The indices 0->5 for cubemap 32 goes as:
// [0, 1, 2] as row 1, left to right
// [3, 4, 5] as row 2, left to right
static const int face_projection_map[] = {
[RIGHT] = 0, [LEFT] = 1, [TOP] = 2,
[BOTTOM] = 3, [FRONT] = 4, [BACK] = 5,
};
float axis_vec_x = cosf(phi) * sinf(theta);
float axis_vec_y = sinf(phi);
float axis_vec_z = cosf(phi) * cosf(theta);
float face_x = 0, face_y = 0;
int face_index = get_cubemap_face_map(axis_vec_x, axis_vec_y, axis_vec_z, &face_x, &face_y);
float x_offset = 1.f / 3.f * (face_projection_map[face_index] % 3);
float y_offset = .5f * (face_projection_map[face_index] / 3);
*x = x_offset + (face_x / DEFAULT_EXPANSION_COEF + 1.f) / 6.f;
*y = y_offset + (face_y / DEFAULT_EXPANSION_COEF + 1.f) / 4.f;
}
static void get_rotated_cubemap_map(float phi, float theta, float expand_coef, float *x, float *y)
{
// face_projection_map maps each cube face to an index representing the face on the projection
// The indices 0->5 for rotated cubemap goes as:
// [0, 1] as row 1, left to right
// [2, 3] as row 2, left to right
// [4, 5] as row 3, left to right
static const int face_projection_map[] = {
[LEFT] = 0, [TOP] = 1,
[FRONT] = 2, [BACK] = 3,
[RIGHT] = 4, [BOTTOM] = 5,
};
float axis_yaw_vec_x, axis_yaw_vec_y, axis_yaw_vec_z;
float axis_pitch_vec_z, axis_pitch_vec_y;
float x_offset, y_offset;
float face_x = 0, face_y = 0;
int face_index;
// Unrotate the cube and fix the face map:
// First undo the 45 degree yaw
theta += M_PI_4_F;
// Now we are looking at the middle of an edge. So convert to axis vector & undo the pitch
axis_yaw_vec_x = cosf(phi) * sinf(theta);
axis_yaw_vec_y = sinf(phi);
axis_yaw_vec_z = cosf(phi) * cosf(theta);
// The pitch axis is along +x, and has value of -45 degree. So, only y and z components change
axis_pitch_vec_z = (axis_yaw_vec_z - axis_yaw_vec_y) / M_SQRT2_F;
axis_pitch_vec_y = (axis_yaw_vec_y + axis_yaw_vec_z) / M_SQRT2_F;
face_index = get_cubemap_face_map(axis_yaw_vec_x, axis_pitch_vec_y, axis_pitch_vec_z, &face_x, &face_y);
// Correct for the orientation of the axes on the faces
if (face_index == LEFT || face_index == FRONT || face_index == RIGHT) {
// x increases downwards & y increases towards left
float upright_y = face_y;
face_y = face_x;
face_x = -upright_y;
} else if (face_index == TOP || face_index == BOTTOM) {
// turn the face upside-down for top and bottom
face_x *= -1.f;
face_y *= -1.f;
}
x_offset = .5f * (face_projection_map[face_index] & 1);
y_offset = 1.f / 3.f * (face_projection_map[face_index] >> 1);
*x = x_offset + (face_x / expand_coef + 1.f) / 4.f;
*y = y_offset + (face_y / expand_coef + 1.f) / 6.f;
}
static void get_projected_map(float phi, float theta, SampleParams *p, BilinearMap *m)
{
float x = 0, y = 0;
switch(p->projection) {
// TODO: Calculate for CDS
case PROJECTION_CUBEMAP23:
get_rotated_cubemap_map(phi, theta, p->expand_coef, &x, &y);
break;
case PROJECTION_CUBEMAP32:
get_cubemap32_map(phi, theta, &x, &y);
break;
case PROJECTION_BARREL:
get_barrel_map(phi, theta, &x, &y);
break;
case PROJECTION_BARREL_SPLIT:
get_barrel_split_map(phi, theta, p->expand_coef, &x, &y);
break;
// Assume PROJECTION_EQUIRECT as the default
case PROJECTION_EQUIRECT:
default:
get_equirect_map(phi, theta, &x, &y);
break;
}
compute_bilinear_map(p, m, x, y);
}
static int tape_supports_projection(int projection)
{
switch(projection) {
case PROJECTION_CUBEMAP23:
case PROJECTION_CUBEMAP32:
case PROJECTION_BARREL:
case PROJECTION_BARREL_SPLIT:
case PROJECTION_EQUIRECT:
return 1;
default:
return 0;
}
}
static float get_tape_angular_resolution(int projection, float expand_coef, int image_width, int image_height)
{
// NOTE: The angular resolution of a projected sphere is defined as
// the maximum possible horizontal angle of a pixel on the equator.
// We apply an intentional bias to the horizon as opposed to the meridian,
// since the view direction of most content is rarely closer to the poles
switch(projection) {
// TODO: Calculate for CDS
case PROJECTION_CUBEMAP23:
// Approximating atanf(pixel_width / (half_edge_width * sqrt2)) = pixel_width / (half_face_width * sqrt2)
return expand_coef / (M_SQRT2_F * image_width / 4.f);
case PROJECTION_CUBEMAP32:
// Approximating atanf(pixel_width / half_face_width) = pixel_width / half_face_width
return DEFAULT_EXPANSION_COEF / (image_width / 6.f);
case PROJECTION_BARREL:
return FFMAX(BARREL_THETA_RANGE / (0.8f * image_width), BARREL_PHI_RANGE / image_height);
case PROJECTION_BARREL_SPLIT:
return FFMAX((expand_coef * M_PI_F) / (2.0f / 3.0f * image_width),
expand_coef * M_PI_2_F / (image_height / 2.0f));
// Assume PROJECTION_EQUIRECT as the default
case PROJECTION_EQUIRECT:
default:
return FFMAX(2.0f * M_PI_F / image_width, M_PI_F / image_height);
}
}
static int
generate_eye_tape_map(SSIM360Context *s,
int plane, int eye,
SampleParams *ref_sample_params,
SampleParams *main_sample_params)
{
int ref_image_width = ref_sample_params->x_image_range + 1;
int ref_image_height = ref_sample_params->y_image_range + 1;
float angular_resolution =
get_tape_angular_resolution(s->ref_projection, 1.f + s->ref_pad,
ref_image_width, ref_image_height);
float conversion_factor = M_PI_2_F / (angular_resolution * angular_resolution);
float start_phi = -M_PI_2_F + 4.0f * angular_resolution;
float start_x = conversion_factor * sinf(start_phi);
float end_phi = M_PI_2_F - 3.0f * angular_resolution;
float end_x = conversion_factor * sinf(end_phi);
float x_range = end_x - start_x;
// Ensure tape length is a multiple of 4, for full SSIM block coverage
int tape_length = s->tape_length[plane] = ((int)ROUNDED_DIV(x_range, 4)) << 2;
s->ref_tape_map[plane][eye] = av_malloc_array(tape_length * 8, sizeof(BilinearMap));
s->main_tape_map[plane][eye] = av_malloc_array(tape_length * 8, sizeof(BilinearMap));
if (!s->ref_tape_map[plane][eye] || !s->main_tape_map[plane][eye])
return AVERROR(ENOMEM);
s->angular_resolution[plane][eye] = angular_resolution;
// For easy memory access, we navigate the tape lengthwise on y
for (int y_index = 0; y_index < tape_length; y_index ++) {
int y_stride = y_index << 3;
float x = start_x + x_range * (y_index / (tape_length - 1.0f));
// phi will be in range [-pi/2, pi/2]
float mid_phi = asinf(x / conversion_factor);
float theta = mid_phi * M_PI_2_F / angular_resolution;
theta = get_radius_between_negative_and_positive_pi(theta);
for (int x_index = 0; x_index < 8; x_index ++) {
float phi = mid_phi + angular_resolution * (3.0f - x_index);
int tape_index = y_stride + x_index;
get_projected_map(phi, theta, ref_sample_params, &s->ref_tape_map [plane][eye][tape_index]);
get_projected_map(phi, theta, main_sample_params, &s->main_tape_map[plane][eye][tape_index]);
}
}
return 0;
}
static int generate_tape_maps(SSIM360Context *s, AVFrame *main, const AVFrame *ref)
{
// A tape is a long segment with 8 pixels thickness, with the angular center at the middle (below 4th pixel).
// When it takes a full loop around a sphere, it will overlap the starting point at half the width from above.
int ref_stereo_format = s->ref_stereo_format;
int main_stereo_format = s->main_stereo_format;
int are_both_stereo = (main_stereo_format != STEREO_FORMAT_MONO) && (ref_stereo_format != STEREO_FORMAT_MONO);
int min_eye_count = 1 + are_both_stereo;
int ret;
for (int i = 0; i < s->nb_components; i ++) {
int ref_width = s->ref_planewidth[i];
int ref_height = s->ref_planeheight[i];
int main_width = s->main_planewidth[i];
int main_height = s->main_planeheight[i];
int is_ref_LR = (ref_stereo_format == STEREO_FORMAT_LR);
int is_ref_TB = (ref_stereo_format == STEREO_FORMAT_TB);
int is_main_LR = (main_stereo_format == STEREO_FORMAT_LR);
int is_main_TB = (main_stereo_format == STEREO_FORMAT_TB);
int ref_image_width = is_ref_LR ? ref_width >> 1 : ref_width;
int ref_image_height = is_ref_TB ? ref_height >> 1 : ref_height;
int main_image_width = is_main_LR ? main_width >> 1 : main_width;
int main_image_height = is_main_TB ? main_height >> 1 : main_height;
for (int eye = 0; eye < min_eye_count; eye ++) {
SampleParams ref_sample_params = {
.stride = ref->linesize[i],
.planewidth = ref_width,
.planeheight = ref_height,
.x_image_range = ref_image_width - 1,
.y_image_range = ref_image_height - 1,
.x_image_offset = is_ref_LR * eye * ref_image_width,
.y_image_offset = is_ref_TB * eye * ref_image_height,
.projection = s->ref_projection,
.expand_coef = 1.f + s->ref_pad,
};
SampleParams main_sample_params = {
.stride = main->linesize[i],
.planewidth = main_width,
.planeheight = main_height,
.x_image_range = main_image_width - 1,
.y_image_range = main_image_height - 1,
.x_image_offset = is_main_LR * eye * main_image_width,
.y_image_offset = is_main_TB * eye * main_image_height,
.projection = s->main_projection,
.expand_coef = 1.f + s->main_pad,
};
ret = generate_eye_tape_map(s, i, eye, &ref_sample_params, &main_sample_params);
if (ret < 0)
return ret;
}
}
return 0;
}
static int do_ssim360(FFFrameSync *fs)
{
AVFilterContext *ctx = fs->parent;
SSIM360Context *s = ctx->priv;
AVFrame *master, *ref;
AVDictionary **metadata;
double c[4], ssim360v = 0.0, ssim360p50 = 0.0;
int i, ret;
int need_frame_skip = s->nb_net_frames % (s->frame_skip_ratio + 1);
HeatmapList* h_ptr = NULL;
ret = ff_framesync_dualinput_get(fs, &master, &ref);
if (ret < 0)
return ret;
s->nb_net_frames++;
if (need_frame_skip)
return ff_filter_frame(ctx->outputs[0], master);
metadata = &master->metadata;
if (s->use_tape && !s->tape_length[0]) {
ret = generate_tape_maps(s, master, ref);
if (ret < 0)
return ret;
}
for (i = 0; i < s->nb_components; i++) {
if (s->use_tape) {
c[i] = ssim360_tape(master->data[i], s->main_tape_map[i][0],
ref->data[i], s->ref_tape_map [i][0],
s->tape_length[i], s->max, s->temp,
s->ssim360_hist[i], &s->ssim360_hist_net[i],
s->angular_resolution[i][0], s->heatmaps);
if (s->ref_tape_map[i][1]) {
c[i] += ssim360_tape(master->data[i], s->main_tape_map[i][1],
ref->data[i], s->ref_tape_map[i][1],
s->tape_length[i], s->max, s->temp,
s->ssim360_hist[i], &s->ssim360_hist_net[i],
s->angular_resolution[i][1], s->heatmaps);
c[i] /= 2.f;
}
} else {
c[i] = s->ssim360_plane(master->data[i], master->linesize[i],
ref->data[i], ref->linesize[i],
s->ref_planewidth[i], s->ref_planeheight[i],
s->temp, s->max, s->density);
}
s->ssim360[i] += c[i];
ssim360v += s->coefs[i] * c[i];
}
s->nb_ssim_frames++;
if (s->heatmaps) {
map_uninit(&s->heatmaps->map);
h_ptr = s->heatmaps;
s->heatmaps = s->heatmaps->next;
av_freep(&h_ptr);
}
s->ssim360_total += ssim360v;
// Record percentiles from histogram and attach metadata when using tape
if (s->use_tape) {
int i, p, hist_indices[4];
double hist_weight[4];
for (i = 0; i < s->nb_components; i++) {
hist_indices[i] = SSIM360_HIST_SIZE - 1;
hist_weight[i] = 0;
}
for (p = 0; PERCENTILE_LIST[p] >= 0.0; p ++) {
for (i = 0; i < s->nb_components; i++) {
double target_weight, ssim360p;
// Target weight = total number of samples above the specified percentile
target_weight = (1. - PERCENTILE_LIST[p]) * s->ssim360_hist_net[i];
target_weight = FFMAX(target_weight, 1);
while(hist_indices[i] >= 0 && hist_weight[i] < target_weight) {
hist_weight[i] += s->ssim360_hist[i][hist_indices[i]];
hist_indices[i] --;
}
ssim360p = (double)(hist_indices[i] + 1) / (double)(SSIM360_HIST_SIZE - 1);
if (PERCENTILE_LIST[p] == 0.5)
ssim360p50 += s->coefs[i] * ssim360p;
s->ssim360_percentile_sum[i][p] += ssim360p;
}
}
for (i = 0; i < s->nb_components; i++) {
memset(s->ssim360_hist[i], 0, SSIM360_HIST_SIZE * sizeof(double));
s->ssim360_hist_net[i] = 0;
}
for (i = 0; i < s->nb_components; i++) {
int cidx = s->is_rgb ? s->rgba_map[i] : i;
set_meta(metadata, "lavfi.ssim360.", s->comps[i], c[cidx]);
}
// Use p50 as the aggregated value
set_meta(metadata, "lavfi.ssim360.All", 0, ssim360p50);
set_meta(metadata, "lavfi.ssim360.dB", 0, ssim360_db(ssim360p50, 1.0));
if (s->stats_file) {
fprintf(s->stats_file, "n:%"PRId64" ", s->nb_ssim_frames);
for (i = 0; i < s->nb_components; i++) {
int cidx = s->is_rgb ? s->rgba_map[i] : i;
fprintf(s->stats_file, "%c:%f ", s->comps[i], c[cidx]);
}
fprintf(s->stats_file, "All:%f (%f)\n", ssim360p50, ssim360_db(ssim360p50, 1.0));
}
}
return ff_filter_frame(ctx->outputs[0], master);
}
static int parse_heatmaps(void *logctx, HeatmapList **proot,
const char *data, int w, int h)
{
HeatmapList *root = NULL;
HeatmapList **next = &root;
int ret;
// skip video id line
data = strchr(data, '\n');
if (!data) {
av_log(logctx, AV_LOG_ERROR, "Invalid heatmap syntax\n");
return AVERROR(EINVAL);
}
data++;
while (*data) {
HeatmapList *cur;
char *line = av_get_token(&data, "\n");
char *saveptr, *val;
int i;
if (!line) {
ret = AVERROR(ENOMEM);
goto fail;
}
// first value is frame id
av_strtok(line, ",", &saveptr);
ret = map_alloc(next, w, h);
if (ret < 0)
goto line_fail;
cur = *next;
next = &cur->next;
i = 0;
while ((val = av_strtok(NULL, ",", &saveptr))) {
if (i >= w * h) {
av_log(logctx, AV_LOG_ERROR, "Too many entries in a heat map\n");
ret = AVERROR(EINVAL);
goto line_fail;
}
cur->map.value[i++] = atof(val);
}
line_fail:
av_freep(&line);
if (ret < 0)
goto fail;
}
*proot = root;
return 0;
fail:
map_list_free(&root);
return ret;
}
static av_cold int init(AVFilterContext *ctx)
{
SSIM360Context *s = ctx->priv;
int err;
if (s->stats_file_str) {
if (!strcmp(s->stats_file_str, "-")) {
s->stats_file = stdout;
} else {
s->stats_file = avpriv_fopen_utf8(s->stats_file_str, "w");
if (!s->stats_file) {
char buf[128];
err = AVERROR(errno);
av_strerror(err, buf, sizeof(buf));
av_log(ctx, AV_LOG_ERROR, "Could not open stats file %s: %s\n",
s->stats_file_str, buf);
return err;
}
}
}
if (s->use_tape && s->heatmap_str) {
err = parse_heatmaps(ctx, &s->heatmaps, s->heatmap_str,
s->default_heatmap_w, s->default_heatmap_h);
if (err < 0)
return err;
}
s->fs.on_event = do_ssim360;
return 0;
}
static int config_input_main(AVFilterLink *inlink)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
AVFilterContext *ctx = inlink->dst;
SSIM360Context *s = ctx->priv;
s->main_planeheight[0] = inlink->h;
s->main_planeheight[3] = inlink->h;
s->main_planeheight[1] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->main_planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->main_planewidth[0] = inlink->w;
s->main_planewidth[3] = inlink->w;
s->main_planewidth[1] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
s->main_planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
// If main projection is unindentified, assume it is same as reference
if (s->main_projection == PROJECTION_N)
s->main_projection = s->ref_projection;
// If main stereo format is unindentified, assume it is same as reference
if (s->main_stereo_format == STEREO_FORMAT_N)
s->main_stereo_format = s->ref_stereo_format;
return 0;
}
static int generate_density_map(SSIM360Context *s, int w, int h)
{
double d, r_square, cos_square;
int ow, oh, ret;
ret = map_init(&s->density, w, h);
if (ret < 0)
return ret;
switch (s->ref_stereo_format) {
case STEREO_FORMAT_TB:
h >>= 1;
break;
case STEREO_FORMAT_LR:
w >>= 1;
break;
}
switch (s->ref_projection) {
case PROJECTION_EQUIRECT:
for (int i = 0; i < h; i++) {
d = cos(((0.5 + i) / h - 0.5) * M_PI);
for (int j = 0; j < w; j++)
s->density.value[i * w + j] = d;
}
break;
case PROJECTION_CUBEMAP32:
// for one quater of a face
for (int i = 0; i < h / 4; i++) {
for (int j = 0; j < w / 6; j++) {
// r = normalized distance to the face center
r_square =
(0.5 + i) / (h / 2) * (0.5 + i) / (h / 2) +
(0.5 + j) / (w / 3) * (0.5 + j) / (w / 3);
r_square /= DEFAULT_EXPANSION_COEF * DEFAULT_EXPANSION_COEF;
cos_square = 0.25 / (r_square + 0.25);
d = pow(cos_square, 1.5);
for (int face = 0; face < 6; face++) {
// center of a face
switch (face) {
case 0:
oh = h / 4;
ow = w / 6;
break;
case 1:
oh = h / 4;
ow = w / 6 + w / 3;
break;
case 2:
oh = h / 4;
ow = w / 6 + 2 * w / 3;
break;
case 3:
oh = h / 4 + h / 2;
ow = w / 6;
break;
case 4:
oh = h / 4 + h / 2;
ow = w / 6 + w / 3;
break;
case 5:
oh = h / 4 + h / 2;
ow = w / 6 + 2 * w / 3;
break;
}
s->density.value[(oh - 1 - i) * w + ow - 1 - j] = d;
s->density.value[(oh - 1 - i) * w + ow + j] = d;
s->density.value[(oh + i) * w + ow - 1 - j] = d;
s->density.value[(oh + i) * w + ow + j] = d;
}
}
}
break;
case PROJECTION_CUBEMAP23:
// for one quater of a face
for (int i = 0; i < h / 6; i++) {
for (int j = 0; j < w / 4; j++) {
// r = normalized distance to the face center
r_square =
(0.5 + i) / (h / 3) * (0.5 + i) / (h / 3) +
(0.5 + j) / (w / 2) * (0.5 + j) / (w / 2);
r_square /= (1.f + s->ref_pad) * (1.f + s->ref_pad);
cos_square = 0.25 / (r_square + 0.25);
d = pow(cos_square, 1.5);
for (int face = 0; face < 6; face++) {
// center of a face
switch (face) {
case 0:
ow = w / 4;
oh = h / 6;
break;
case 1:
ow = w / 4;
oh = h / 6 + h / 3;
break;
case 2:
ow = w / 4;
oh = h / 6 + 2 * h / 3;
break;
case 3:
ow = w / 4 + w / 2;
oh = h / 6;
break;
case 4:
ow = w / 4 + w / 2;
oh = h / 6 + h / 3;
break;
case 5:
ow = w / 4 + w / 2;
oh = h / 6 + 2 * h / 3;
break;
}
s->density.value[(oh - 1 - i) * w + ow - 1 - j] = d;
s->density.value[(oh - 1 - i) * w + ow + j] = d;
s->density.value[(oh + i) * w + ow - 1 - j] = d;
s->density.value[(oh + i) * w + ow + j] = d;
}
}
}
break;
case PROJECTION_BARREL:
// side face
for (int i = 0; i < h; i++) {
for (int j = 0; j < w * 4 / 5; j++) {
d = cos(((0.5 + i) / h - 0.5) * DEFAULT_EXPANSION_COEF * M_PI_2);
s->density.value[i * w + j] = d * d * d;
}
}
// top and bottom
for (int i = 0; i < h; i++) {
for (int j = w * 4 / 5; j < w; j++) {
double dx = DEFAULT_EXPANSION_COEF * (0.5 + j - w * 0.90) / (w * 0.10);
double dx_squared = dx * dx;
double top_dy = DEFAULT_EXPANSION_COEF * (0.5 + i - h * 0.25) / (h * 0.25);
double top_dy_squared = top_dy * top_dy;
double bottom_dy = DEFAULT_EXPANSION_COEF * (0.5 + i - h * 0.75) / (h * 0.25);
double bottom_dy_squared = bottom_dy * bottom_dy;
// normalized distance to the circle center
r_square = (i < h / 2 ? top_dy_squared : bottom_dy_squared) + dx_squared;
if (r_square > 1.0)
continue;
cos_square = 1.0 / (r_square + 1.0);
d = pow(cos_square, 1.5);
s->density.value[i * w + j] = d;
}
}
break;
default:
// TODO: SSIM360_v1
for (int i = 0; i < h; i++) {
for (int j = 0; j < w; j++)
s->density.value[i * w + j] = 0;
}
}
switch (s->ref_stereo_format) {
case STEREO_FORMAT_TB:
for (int i = 0; i < h; i++) {
for (int j = 0; j < w; j++)
s->density.value[(i + h) * w + j] = s->density.value[i * w + j];
}
break;
case STEREO_FORMAT_LR:
for (int i = 0; i < h; i++) {
for (int j = 0; j < w; j++)
s->density.value[i * w + j + w] = s->density.value[i * w + j];
}
}
return 0;
}
static int config_input_ref(AVFilterLink *inlink)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
AVFilterContext *ctx = inlink->dst;
SSIM360Context *s = ctx->priv;
int sum = 0;
s->nb_components = desc->nb_components;
s->ref_planeheight[0] = inlink->h;
s->ref_planeheight[3] = inlink->h;
s->ref_planeheight[1] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->ref_planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
s->ref_planewidth[0] = inlink->w;
s->ref_planewidth[3] = inlink->w;
s->ref_planewidth[1] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
s->ref_planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
s->is_rgb = ff_fill_rgba_map(s->rgba_map, inlink->format) >= 0;
s->comps[0] = s->is_rgb ? 'R' : 'Y';
s->comps[1] = s->is_rgb ? 'G' : 'U';
s->comps[2] = s->is_rgb ? 'B' : 'V';
s->comps[3] = 'A';
// If chroma computation is disabled, and the format is YUV, skip U & V channels
if (!s->is_rgb && !s->compute_chroma)
s->nb_components = 1;
s->max = (1 << desc->comp[0].depth) - 1;
s->ssim360_plane = desc->comp[0].depth > 8 ? ssim360_plane_16bit : ssim360_plane_8bit;
for (int i = 0; i < s->nb_components; i++)
sum += s->ref_planeheight[i] * s->ref_planewidth[i];
for (int i = 0; i < s->nb_components; i++)
s->coefs[i] = (double) s->ref_planeheight[i] * s->ref_planewidth[i] / sum;
return 0;
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
SSIM360Context *s = ctx->priv;
AVFilterLink *mainlink = ctx->inputs[0];
AVFilterLink *reflink = ctx->inputs[0];
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
int ret;
// Use tape algorithm if any of frame sizes, projections or stereo format are not equal
if (ctx->inputs[0]->w != ctx->inputs[1]->w || ctx->inputs[0]->h != ctx->inputs[1]->h ||
s->ref_projection != s->main_projection || s->ref_stereo_format != s->main_stereo_format)
s->use_tape = 1;
// Finally, if we have decided to / forced to use tape, check if tape supports both input and output projection
if (s->use_tape &&
!(tape_supports_projection(s->main_projection) &&
tape_supports_projection(s->ref_projection))) {
av_log(ctx, AV_LOG_ERROR, "Projection is unsupported for the tape based algorithm\n");
return AVERROR(EINVAL);
}
if (s->use_tape) {
// s->temp will be allocated for the tape width = 8. The tape is long downwards
s->temp = av_malloc_array((2 * 8 + 12), sizeof(*s->temp));
if (!s->temp)
return AVERROR(ENOMEM);
memset(s->ssim360_percentile_sum, 0, sizeof(s->ssim360_percentile_sum));
for (int i = 0; i < s->nb_components; i++) {
FF_ALLOCZ_TYPED_ARRAY(s->ssim360_hist[i], SSIM360_HIST_SIZE);
if (!s->ssim360_hist[i])
return AVERROR(ENOMEM);
}
} else {
s->temp = av_malloc_array((2 * reflink->w + 12), sizeof(*s->temp) * (1 + (desc->comp[0].depth > 8)));
if (!s->temp)
return AVERROR(ENOMEM);
if (!s->density.value) {
ret = generate_density_map(s, reflink->w, reflink->h);
if (ret < 0)
return ret;
}
}
ret = ff_framesync_init_dualinput(&s->fs, ctx);
if (ret < 0)
return ret;
outlink->w = mainlink->w;
outlink->h = mainlink->h;
outlink->time_base = mainlink->time_base;
outlink->sample_aspect_ratio = mainlink->sample_aspect_ratio;
outlink->frame_rate = mainlink->frame_rate;
s->fs.opt_shortest = 1;
s->fs.opt_repeatlast = 1;
ret = ff_framesync_configure(&s->fs);
if (ret < 0)
return ret;
return 0;
}
static int activate(AVFilterContext *ctx)
{
SSIM360Context *s = ctx->priv;
return ff_framesync_activate(&s->fs);
}
static av_cold void uninit(AVFilterContext *ctx)
{
SSIM360Context *s = ctx->priv;
if (s->nb_ssim_frames > 0) {
char buf[256];
buf[0] = 0;
// Log average SSIM360 values
for (int i = 0; i < s->nb_components; i++) {
int c = s->is_rgb ? s->rgba_map[i] : i;
av_strlcatf(buf, sizeof(buf), " %c:%f (%f)", s->comps[i], s->ssim360[c] / s->nb_ssim_frames,
ssim360_db(s->ssim360[c], s->nb_ssim_frames));
}
av_log(ctx, AV_LOG_INFO, "SSIM360%s All:%f (%f)\n", buf,
s->ssim360_total / s->nb_ssim_frames, ssim360_db(s->ssim360_total, s->nb_ssim_frames));
// Log percentiles from histogram when using tape
if (s->use_tape) {
for (int p = 0; PERCENTILE_LIST[p] >= 0.0; p++) {
buf[0] = 0;
for (int i = 0; i < s->nb_components; i++) {
int c = s->is_rgb ? s->rgba_map[i] : i;
double ssim360p = s->ssim360_percentile_sum[i][p] / (double)(s->nb_ssim_frames);
av_strlcatf(buf, sizeof(buf), " %c:%f (%f)", s->comps[c], ssim360p, ssim360_db(ssim360p, 1));
}
av_log(ctx, AV_LOG_INFO, "SSIM360_p%d%s\n", (int)(PERCENTILE_LIST[p] * 100.), buf);
}
}
}
// free density map
map_uninit(&s->density);
map_list_free(&s->heatmaps);
for (int i = 0; i < s->nb_components; i++) {
for (int eye = 0; eye < 2; eye++) {
av_freep(&s->ref_tape_map[i][eye]);
av_freep(&s->main_tape_map[i][eye]);
}
av_freep(&s->ssim360_hist[i]);
}
ff_framesync_uninit(&s->fs);
if (s->stats_file && s->stats_file != stdout)
fclose(s->stats_file);
av_freep(&s->temp);
}
#define PF(suf) AV_PIX_FMT_YUV420##suf, AV_PIX_FMT_YUV422##suf, AV_PIX_FMT_YUV444##suf, AV_PIX_FMT_GBR##suf
static const enum AVPixelFormat ssim360_pixfmts[] = {
AV_PIX_FMT_GRAY8,
AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
AV_PIX_FMT_GBRP,
PF(P9), PF(P10), PF(P12), PF(P14), PF(P16),
AV_PIX_FMT_NONE
};
#undef PF
static const AVFilterPad ssim360_inputs[] = {
{
.name = "main",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input_main,
},
{
.name = "reference",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input_ref,
},
};
static const AVFilterPad ssim360_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output,
},
};
const AVFilter ff_vf_ssim360 = {
.name = "ssim360",
.description = NULL_IF_CONFIG_SMALL("Calculate the SSIM between two 360 video streams."),
.preinit = ssim360_framesync_preinit,
.init = init,
.uninit = uninit,
.activate = activate,
.priv_size = sizeof(SSIM360Context),
.priv_class = &ssim360_class,
FILTER_INPUTS(ssim360_inputs),
FILTER_OUTPUTS(ssim360_outputs),
FILTER_PIXFMTS_ARRAY(ssim360_pixfmts),
};
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