/** * 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 #include "libavutil/avstring.h" #include "libavutil/file_open.h" #include "libavutil/opt.h" #include "libavutil/pixdesc.h" #include "avfilter.h" #include "drawutils.h" #include "formats.h" #include "internal.h" #include "video.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, "projection" }, { "e", "equirectangular", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_EQUIRECT}, 0, 0, FLAGS, "projection" }, { "equirect", "equirectangular", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_EQUIRECT}, 0, 0, FLAGS, "projection" }, { "c3x2", "cubemap 3x2", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_CUBEMAP32}, 0, 0, FLAGS, "projection" }, { "c2x3", "cubemap 2x3", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_CUBEMAP23}, 0, 0, FLAGS, "projection" }, { "barrel", "barrel facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_BARREL}, 0, 0, FLAGS, "projection" }, { "barrelsplit", "barrel split facebook's 360 format", 0, AV_OPT_TYPE_CONST, {.i64 = PROJECTION_BARREL_SPLIT}, 0, 0, FLAGS, "projection" }, { "main_projection", "projection of the main video", OFFSET(main_projection), AV_OPT_TYPE_INT, {.i64 = PROJECTION_N}, 0, PROJECTION_N, .flags = FLAGS, "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, "stereo_format" }, { "mono", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = STEREO_FORMAT_MONO }, 0, 0, FLAGS, "stereo_format" }, { "tb", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = STEREO_FORMAT_TB }, 0, 0, FLAGS, "stereo_format" }, { "lr", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = STEREO_FORMAT_LR }, 0, 0, FLAGS, "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, "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), };