From 9026d92c137fab532e86da101fb939c1f79ff18f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= Date: Tue, 27 Dec 2022 15:33:15 +0100 Subject: [PATCH] avfilter/palettegen: base box split decision on a perceptual model Similar to the change in paletteuse, we rely on a perceptual model to decide how and where to split the box. --- libavfilter/Makefile | 2 +- libavfilter/vf_palettegen.c | 48 ++++++++++++++++-------------- tests/ref/fate/filter-palettegen-1 | 2 +- tests/ref/fate/filter-palettegen-2 | 2 +- 4 files changed, 29 insertions(+), 25 deletions(-) diff --git a/libavfilter/Makefile b/libavfilter/Makefile index c3d13e5a26..5783be281d 100644 --- a/libavfilter/Makefile +++ b/libavfilter/Makefile @@ -403,7 +403,7 @@ OBJS-$(CONFIG_OVERLAY_VULKAN_FILTER) += vf_overlay_vulkan.o vulkan.o vul OBJS-$(CONFIG_OWDENOISE_FILTER) += vf_owdenoise.o OBJS-$(CONFIG_PAD_FILTER) += vf_pad.o OBJS-$(CONFIG_PAD_OPENCL_FILTER) += vf_pad_opencl.o opencl.o opencl/pad.o -OBJS-$(CONFIG_PALETTEGEN_FILTER) += vf_palettegen.o +OBJS-$(CONFIG_PALETTEGEN_FILTER) += vf_palettegen.o palette.o OBJS-$(CONFIG_PALETTEUSE_FILTER) += vf_paletteuse.o framesync.o palette.o OBJS-$(CONFIG_PERMS_FILTER) += f_perms.o OBJS-$(CONFIG_PERSPECTIVE_FILTER) += vf_perspective.o diff --git a/libavfilter/vf_palettegen.c b/libavfilter/vf_palettegen.c index 99e4512e52..3178c43ab9 100644 --- a/libavfilter/vf_palettegen.c +++ b/libavfilter/vf_palettegen.c @@ -30,16 +30,19 @@ #include "libavutil/intreadwrite.h" #include "avfilter.h" #include "internal.h" +#include "palette.h" /* Reference a color and how much it's used */ struct color_ref { uint32_t color; + struct Lab lab; int64_t count; }; /* Store a range of colors */ struct range_box { uint32_t color; // average color + struct Lab avg; // average color in perceptual OkLab space int major_axis; // best axis candidate for cutting the box int64_t weight; // sum of all the weights of the colors int64_t cut_score; // how likely the box is to be cut down (higher implying more likely) @@ -115,15 +118,14 @@ static int cmp_##name(const void *pa, const void *pb) \ { \ const struct color_ref * const *a = pa; \ const struct color_ref * const *b = pb; \ - return (int)((*a)->color >> (8 * (2 - (pos))) & 0xff) \ - - (int)((*b)->color >> (8 * (2 - (pos))) & 0xff); \ + return FFDIFFSIGN((*a)->lab.name, (*b)->lab.name); \ } -DECLARE_CMP_FUNC(r, 0) -DECLARE_CMP_FUNC(g, 1) +DECLARE_CMP_FUNC(L, 0) +DECLARE_CMP_FUNC(a, 1) DECLARE_CMP_FUNC(b, 2) -static const cmp_func cmp_funcs[] = {cmp_r, cmp_g, cmp_b}; +static const cmp_func cmp_funcs[] = {cmp_L, cmp_a, cmp_b}; /** * Simple color comparison for sorting the final palette @@ -137,40 +139,38 @@ static int cmp_color(const void *a, const void *b) static void compute_box_stats(PaletteGenContext *s, struct range_box *box) { - int avg[3]; int64_t er2[3] = {0}; /* Compute average color */ - int64_t sr = 0, sg = 0, sb = 0; + int64_t sL = 0, sa = 0, sb = 0; box->weight = 0; for (int i = box->start; i < box->start + box->len; i++) { const struct color_ref *ref = s->refs[i]; - sr += (ref->color >> 16 & 0xff) * ref->count; - sg += (ref->color >> 8 & 0xff) * ref->count; - sb += (ref->color & 0xff) * ref->count; + sL += ref->lab.L * ref->count; + sa += ref->lab.a * ref->count; + sb += ref->lab.b * ref->count; box->weight += ref->count; } - avg[0] = sr / box->weight; - avg[1] = sg / box->weight; - avg[2] = sb / box->weight; - box->color = 0xffU<<24 | avg[0]<<16 | avg[1]<<8 | avg[2]; + box->avg.L = sL / box->weight; + box->avg.a = sa / box->weight; + box->avg.b = sb / box->weight; /* Compute squared error of each color channel */ for (int i = box->start; i < box->start + box->len; i++) { const struct color_ref *ref = s->refs[i]; - const int64_t dr = (int)(ref->color >> 16 & 0xff) - avg[0]; - const int64_t dg = (int)(ref->color >> 8 & 0xff) - avg[1]; - const int64_t db = (int)(ref->color & 0xff) - avg[2]; - er2[0] += dr * dr * ref->count; - er2[1] += dg * dg * ref->count; + const int64_t dL = ref->lab.L - box->avg.L; + const int64_t da = ref->lab.a - box->avg.a; + const int64_t db = ref->lab.b - box->avg.b; + er2[0] += dL * dL * ref->count; + er2[1] += da * da * ref->count; er2[2] += db * db * ref->count; } /* Define the best axis candidate for cutting the box */ - box->major_axis = 1; // pick green by default (the color the eye is the most sensitive to) + box->major_axis = 0; if (er2[2] >= er2[0] && er2[2] >= er2[1]) box->major_axis = 2; + if (er2[1] >= er2[0] && er2[1] >= er2[2]) box->major_axis = 1; if (er2[0] >= er2[1] && er2[0] >= er2[2]) box->major_axis = 0; - if (er2[1] >= er2[0] && er2[1] >= er2[2]) box->major_axis = 1; // prefer green again /* The box that has the axis with the biggest error amongst all boxes will but cut down */ box->cut_score = FFMAX3(er2[0], er2[1], er2[2]); @@ -318,7 +318,7 @@ static AVFrame *get_palette_frame(AVFilterContext *ctx) ff_dlog(ctx, "box #%02X [%6d..%-6d] (%6d) w:%-6"PRIu64" sort by %c (already sorted:%c) ", box_id, box->start, box->start + box->len - 1, box->len, box->weight, - "rgb"[box->major_axis], box->sorted_by == box->major_axis ? 'y':'n'); + "Lab"[box->major_axis], box->sorted_by == box->major_axis ? 'y':'n'); /* sort the range by its major axis if it's not already sorted */ if (box->sorted_by != box->major_axis) { @@ -348,6 +348,9 @@ static AVFrame *get_palette_frame(AVFilterContext *ctx) av_log(ctx, AV_LOG_INFO, "%d%s colors generated out of %d colors; ratio=%f\n", s->nb_boxes, s->reserve_transparent ? "(+1)" : "", s->nb_refs, ratio); + for (int i = 0; i < s->nb_boxes; i++) + s->boxes[i].color = 0xffU<<24 | ff_oklab_int_to_srgb_u8(s->boxes[i].avg); + qsort(s->boxes, s->nb_boxes, sizeof(*s->boxes), cmp_color); write_palette(ctx, out); @@ -392,6 +395,7 @@ static int color_inc(struct hist_node *hist, uint32_t color) if (!e) return AVERROR(ENOMEM); e->color = color; + e->lab = ff_srgb_u8_to_oklab_int(color); e->count = 1; return 1; } diff --git a/tests/ref/fate/filter-palettegen-1 b/tests/ref/fate/filter-palettegen-1 index 57be338b42..bae6b7064b 100644 --- a/tests/ref/fate/filter-palettegen-1 +++ b/tests/ref/fate/filter-palettegen-1 @@ -3,4 +3,4 @@ #codec_id 0: rawvideo #dimensions 0: 16x16 #sar 0: 1/1 -0, 0, 0, 1, 1024, 0x21c6e6c4 +0, 0, 0, 1, 1024, 0xbb5cde01 diff --git a/tests/ref/fate/filter-palettegen-2 b/tests/ref/fate/filter-palettegen-2 index bcdf54af95..7217de3a92 100644 --- a/tests/ref/fate/filter-palettegen-2 +++ b/tests/ref/fate/filter-palettegen-2 @@ -3,4 +3,4 @@ #codec_id 0: rawvideo #dimensions 0: 16x16 #sar 0: 1/1 -0, 0, 0, 1, 1024, 0x630d76b1 +0, 0, 0, 1, 1024, 0xfbf66e70