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			631 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			631 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2015 Stupeflix
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|  *
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|  * This file is part of FFmpeg.
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|  *
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|  * FFmpeg is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2.1 of the License, or (at your option) any later version.
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|  *
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|  * FFmpeg is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with FFmpeg; if not, write to the Free Software
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|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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|  */
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| 
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| /**
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|  * @file
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|  * Generate one palette for a whole video stream.
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|  */
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| 
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| #include "libavutil/avassert.h"
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| #include "libavutil/internal.h"
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| #include "libavutil/opt.h"
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| #include "libavutil/qsort.h"
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| #include "libavutil/intreadwrite.h"
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| #include "avfilter.h"
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| #include "internal.h"
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| 
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| /* Reference a color and how much it's used */
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| struct color_ref {
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|     uint32_t color;
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|     uint64_t count;
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| };
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| 
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| /* Store a range of colors */
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| struct range_box {
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|     uint32_t color;     // average color
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|     int64_t variance;   // overall variance of the box (how much the colors are spread)
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|     int start;          // index in PaletteGenContext->refs
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|     int len;            // number of referenced colors
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|     int sorted_by;      // whether range of colors is sorted by red (0), green (1) or blue (2)
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| };
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| 
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| struct hist_node {
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|     struct color_ref *entries;
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|     int nb_entries;
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| };
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| 
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| enum {
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|     STATS_MODE_ALL_FRAMES,
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|     STATS_MODE_DIFF_FRAMES,
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|     STATS_MODE_SINGLE_FRAMES,
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|     NB_STATS_MODE
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| };
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| 
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| #define NBITS 5
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| #define HIST_SIZE (1<<(4*NBITS))
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| 
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| typedef struct PaletteGenContext {
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|     const AVClass *class;
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| 
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|     int max_colors;
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|     int reserve_transparent;
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|     int stats_mode;
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|     int use_alpha;
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| 
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|     AVFrame *prev_frame;                    // previous frame used for the diff stats_mode
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|     struct hist_node histogram[HIST_SIZE];  // histogram/hashtable of the colors
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|     struct color_ref **refs;                // references of all the colors used in the stream
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|     int nb_refs;                            // number of color references (or number of different colors)
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|     struct range_box boxes[256];            // define the segmentation of the colorspace (the final palette)
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|     int nb_boxes;                           // number of boxes (increase will segmenting them)
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|     int palette_pushed;                     // if the palette frame is pushed into the outlink or not
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|     uint8_t transparency_color[4];          // background color for transparency
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| } PaletteGenContext;
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| 
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| #define OFFSET(x) offsetof(PaletteGenContext, x)
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| #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
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| static const AVOption palettegen_options[] = {
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|     { "max_colors", "set the maximum number of colors to use in the palette", OFFSET(max_colors), AV_OPT_TYPE_INT, {.i64=256}, 4, 256, FLAGS },
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|     { "reserve_transparent", "reserve a palette entry for transparency", OFFSET(reserve_transparent), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },
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|     { "transparency_color", "set a background color for transparency", OFFSET(transparency_color), AV_OPT_TYPE_COLOR, {.str="lime"}, 0, 0, FLAGS },
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|     { "stats_mode", "set statistics mode", OFFSET(stats_mode), AV_OPT_TYPE_INT, {.i64=STATS_MODE_ALL_FRAMES}, 0, NB_STATS_MODE-1, FLAGS, "mode" },
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|         { "full", "compute full frame histograms", 0, AV_OPT_TYPE_CONST, {.i64=STATS_MODE_ALL_FRAMES}, INT_MIN, INT_MAX, FLAGS, "mode" },
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|         { "diff", "compute histograms only for the part that differs from previous frame", 0, AV_OPT_TYPE_CONST, {.i64=STATS_MODE_DIFF_FRAMES}, INT_MIN, INT_MAX, FLAGS, "mode" },
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|         { "single", "compute new histogram for each frame", 0, AV_OPT_TYPE_CONST, {.i64=STATS_MODE_SINGLE_FRAMES}, INT_MIN, INT_MAX, FLAGS, "mode" },
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|     { "use_alpha", "create a palette including alpha values", OFFSET(use_alpha), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS },
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|     { NULL }
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| };
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| 
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| AVFILTER_DEFINE_CLASS(palettegen);
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| 
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| static int query_formats(AVFilterContext *ctx)
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| {
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|     static const enum AVPixelFormat in_fmts[]  = {AV_PIX_FMT_RGB32, AV_PIX_FMT_NONE};
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|     static const enum AVPixelFormat out_fmts[] = {AV_PIX_FMT_RGB32, AV_PIX_FMT_NONE};
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|     int ret;
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| 
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|     if ((ret = ff_formats_ref(ff_make_format_list(in_fmts) , &ctx->inputs[0]->outcfg.formats)) < 0)
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|         return ret;
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|     if ((ret = ff_formats_ref(ff_make_format_list(out_fmts), &ctx->outputs[0]->incfg.formats)) < 0)
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|         return ret;
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|     return 0;
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| }
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| 
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| typedef int (*cmp_func)(const void *, const void *);
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| 
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| #define DECLARE_CMP_FUNC(name, pos)                     \
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| static int cmp_##name(const void *pa, const void *pb)   \
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| {                                                       \
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|     const struct color_ref * const *a = pa;             \
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|     const struct color_ref * const *b = pb;             \
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|     return   (int)((*a)->color >> (8 * (3 - (pos))) & 0xff)  \
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|            - (int)((*b)->color >> (8 * (3 - (pos))) & 0xff); \
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| }
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| 
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| DECLARE_CMP_FUNC(a, 0)
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| DECLARE_CMP_FUNC(r, 1)
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| DECLARE_CMP_FUNC(g, 2)
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| DECLARE_CMP_FUNC(b, 3)
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| 
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| static const cmp_func cmp_funcs[] = {cmp_a, cmp_r, cmp_g, cmp_b};
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| 
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| /**
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|  * Simple color comparison for sorting the final palette
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|  */
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| static int cmp_color(const void *a, const void *b)
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| {
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|     const struct range_box *box1 = a;
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|     const struct range_box *box2 = b;
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|     return FFDIFFSIGN(box1->color , box2->color);
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| }
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| 
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| static av_always_inline int diff(const uint32_t a, const uint32_t b)
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| {
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|     const uint8_t c1[] = {a >> 16 & 0xff, a >> 8 & 0xff, a & 0xff};
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|     const uint8_t c2[] = {b >> 16 & 0xff, b >> 8 & 0xff, b & 0xff};
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|     const int dr = c1[0] - c2[0];
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|     const int dg = c1[1] - c2[1];
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|     const int db = c1[2] - c2[2];
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|     return dr*dr + dg*dg + db*db;
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| }
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| 
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| static av_always_inline int diff_alpha(const uint32_t a, const uint32_t b)
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| {
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|     const uint8_t c1[] = {a >> 24 & 0xff, a >> 16 & 0xff, a >> 8 & 0xff, a & 0xff};
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|     const uint8_t c2[] = {b >> 24 & 0xff, b >> 16 & 0xff, b >> 8 & 0xff, b & 0xff};
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|     const int da = c1[0] - c2[0];
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|     const int dr = c1[1] - c2[1];
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|     const int dg = c1[2] - c2[2];
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|     const int db = c1[3] - c2[3];
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|     return da*da + dr*dr + dg*dg + db*db;
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| }
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| 
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| /**
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|  * Find the next box to split: pick the one with the highest variance
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|  */
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| static int get_next_box_id_to_split(PaletteGenContext *s)
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| {
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|     int box_id, i, best_box_id = -1;
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|     int64_t max_variance = -1;
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| 
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|     if (s->nb_boxes == s->max_colors - s->reserve_transparent)
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|         return -1;
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| 
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|     for (box_id = 0; box_id < s->nb_boxes; box_id++) {
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|         struct range_box *box = &s->boxes[box_id];
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| 
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|         if (s->boxes[box_id].len >= 2) {
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| 
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|             if (box->variance == -1) {
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|                 int64_t variance = 0;
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| 
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|                 for (i = 0; i < box->len; i++) {
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|                     const struct color_ref *ref = s->refs[box->start + i];
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|                     if (s->use_alpha)
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|                         variance += (int64_t)diff_alpha(ref->color, box->color) * ref->count;
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|                     else
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|                         variance += (int64_t)diff(ref->color, box->color) * ref->count;
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|                 }
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|                 box->variance = variance;
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|             }
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|             if (box->variance > max_variance) {
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|                 best_box_id = box_id;
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|                 max_variance = box->variance;
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|             }
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|         } else {
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|             box->variance = -1;
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|         }
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|     }
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|     return best_box_id;
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| }
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| 
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| /**
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|  * Get the 32-bit average color for the range of RGB colors enclosed in the
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|  * specified box. Takes into account the weight of each color.
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|  */
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| static uint32_t get_avg_color(struct color_ref * const *refs,
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|                               const struct range_box *box, int use_alpha)
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| {
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|     int i;
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|     const int n = box->len;
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|     uint64_t a = 0, r = 0, g = 0, b = 0, div = 0;
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| 
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|     for (i = 0; i < n; i++) {
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|         const struct color_ref *ref = refs[box->start + i];
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|         if (use_alpha)
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|             a += (ref->color >> 24 & 0xff) * ref->count;
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|         r += (ref->color     >> 16 & 0xff) * ref->count;
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|         g += (ref->color     >>  8 & 0xff) * ref->count;
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|         b += (ref->color           & 0xff) * ref->count;
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|         div += ref->count;
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|     }
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| 
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|     if (use_alpha)
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|         a = a / div;
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|     r = r / div;
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|     g = g / div;
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|     b = b / div;
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| 
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|     if (use_alpha)
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|         return a<<24 | r<<16 | g<<8 | b;
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| 
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|     return 0xffU<<24 | r<<16 | g<<8 | b;
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| }
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| 
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| /**
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|  * Split given box in two at position n. The original box becomes the left part
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|  * of the split, and the new index box is the right part.
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|  */
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| static void split_box(PaletteGenContext *s, struct range_box *box, int n)
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| {
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|     struct range_box *new_box = &s->boxes[s->nb_boxes++];
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|     new_box->start     = n + 1;
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|     new_box->len       = box->start + box->len - new_box->start;
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|     new_box->sorted_by = box->sorted_by;
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|     box->len -= new_box->len;
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| 
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|     av_assert0(box->len     >= 1);
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|     av_assert0(new_box->len >= 1);
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| 
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|     box->color     = get_avg_color(s->refs, box, s->use_alpha);
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|     new_box->color = get_avg_color(s->refs, new_box, s->use_alpha);
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|     box->variance     = -1;
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|     new_box->variance = -1;
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| }
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| 
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| /**
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|  * Write the palette into the output frame.
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|  */
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| static void write_palette(AVFilterContext *ctx, AVFrame *out)
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| {
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|     const PaletteGenContext *s = ctx->priv;
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|     int x, y, box_id = 0;
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|     uint32_t *pal = (uint32_t *)out->data[0];
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|     const int pal_linesize = out->linesize[0] >> 2;
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|     uint32_t last_color = 0;
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| 
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|     for (y = 0; y < out->height; y++) {
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|         for (x = 0; x < out->width; x++) {
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|             if (box_id < s->nb_boxes) {
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|                 pal[x] = s->boxes[box_id++].color;
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|                 if ((x || y) && pal[x] == last_color)
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|                     av_log(ctx, AV_LOG_WARNING, "Duped color: %08"PRIX32"\n", pal[x]);
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|                 last_color = pal[x];
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|             } else {
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|                 pal[x] = last_color; // pad with last color
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|             }
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|         }
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|         pal += pal_linesize;
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|     }
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| 
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|     if (s->reserve_transparent && !s->use_alpha) {
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|         av_assert0(s->nb_boxes < 256);
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|         pal[out->width - pal_linesize - 1] = AV_RB32(&s->transparency_color) >> 8;
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|     }
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| }
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| 
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| /**
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|  * Crawl the histogram to get all the defined colors, and create a linear list
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|  * of them (each color reference entry is a pointer to the value in the
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|  * histogram/hash table).
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|  */
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| static struct color_ref **load_color_refs(const struct hist_node *hist, int nb_refs)
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| {
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|     int i, j, k = 0;
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|     struct color_ref **refs = av_malloc_array(nb_refs, sizeof(*refs));
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| 
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|     if (!refs)
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|         return NULL;
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| 
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|     for (j = 0; j < HIST_SIZE; j++) {
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|         const struct hist_node *node = &hist[j];
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| 
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|         for (i = 0; i < node->nb_entries; i++)
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|             refs[k++] = &node->entries[i];
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|     }
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| 
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|     return refs;
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| }
 | |
| 
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| static double set_colorquant_ratio_meta(AVFrame *out, int nb_out, int nb_in)
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| {
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|     char buf[32];
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|     const double ratio = (double)nb_out / nb_in;
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|     snprintf(buf, sizeof(buf), "%f", ratio);
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|     av_dict_set(&out->metadata, "lavfi.color_quant_ratio", buf, 0);
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|     return ratio;
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| }
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| 
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| /**
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|  * Main function implementing the Median Cut Algorithm defined by Paul Heckbert
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|  * in Color Image Quantization for Frame Buffer Display (1982)
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|  */
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| static AVFrame *get_palette_frame(AVFilterContext *ctx)
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| {
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|     AVFrame *out;
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|     PaletteGenContext *s = ctx->priv;
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|     AVFilterLink *outlink = ctx->outputs[0];
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|     double ratio;
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|     int box_id = 0;
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|     struct range_box *box;
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| 
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|     /* reference only the used colors from histogram */
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|     s->refs = load_color_refs(s->histogram, s->nb_refs);
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|     if (!s->refs) {
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|         av_log(ctx, AV_LOG_ERROR, "Unable to allocate references for %d different colors\n", s->nb_refs);
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|         return NULL;
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|     }
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| 
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|     /* create the palette frame */
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|     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
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|     if (!out)
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|         return NULL;
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|     out->pts = 0;
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| 
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|     /* set first box for 0..nb_refs */
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|     box = &s->boxes[box_id];
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|     box->len = s->nb_refs;
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|     box->sorted_by = -1;
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|     box->color = get_avg_color(s->refs, box, s->use_alpha);
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|     box->variance = -1;
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|     s->nb_boxes = 1;
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| 
 | |
|     while (box && box->len > 1) {
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|         int i, ar, rr, gr, br, longest;
 | |
|         uint64_t median, box_weight = 0;
 | |
| 
 | |
|         /* compute the box weight (sum all the weights of the colors in the
 | |
|          * range) and its boundings */
 | |
|         uint8_t min[4] = {0xff, 0xff, 0xff, 0xff};
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|         uint8_t max[4] = {0x00, 0x00, 0x00, 0x00};
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|         for (i = box->start; i < box->start + box->len; i++) {
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|             const struct color_ref *ref = s->refs[i];
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|             const uint32_t rgb = ref->color;
 | |
|             const uint8_t a = rgb >> 24 & 0xff, r = rgb >> 16 & 0xff, g = rgb >> 8 & 0xff, b = rgb & 0xff;
 | |
|             min[0] = FFMIN(a, min[0]); max[0] = FFMAX(a, max[0]);
 | |
|             min[1] = FFMIN(r, min[1]); max[1] = FFMAX(r, max[1]);
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|             min[2] = FFMIN(g, min[2]); max[2] = FFMAX(g, max[2]);
 | |
|             min[3] = FFMIN(b, min[3]); max[3] = FFMAX(b, max[3]);
 | |
|             box_weight += ref->count;
 | |
|         }
 | |
| 
 | |
|         /* define the axis to sort by according to the widest range of colors */
 | |
|         ar = max[0] - min[0];
 | |
|         rr = max[1] - min[1];
 | |
|         gr = max[2] - min[2];
 | |
|         br = max[3] - min[3];
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|         longest = 2; // pick green by default (the color the eye is the most sensitive to)
 | |
|         if (s->use_alpha) {
 | |
|             if (ar >= rr && ar >= br && ar >= gr) longest = 0;
 | |
|             if (br >= rr && br >= gr && br >= ar) longest = 3;
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|             if (rr >= gr && rr >= br && rr >= ar) longest = 1;
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|             if (gr >= rr && gr >= br && gr >= ar) longest = 2; // prefer green again
 | |
|         } else {
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|             if (br >= rr && br >= gr) longest = 3;
 | |
|             if (rr >= gr && rr >= br) longest = 1;
 | |
|             if (gr >= rr && gr >= br) longest = 2; // prefer green again
 | |
|         }
 | |
| 
 | |
|         ff_dlog(ctx, "box #%02X [%6d..%-6d] (%6d) w:%-6"PRIu64" ranges:[%2x %2x %2x %2x] sort by %c (already sorted:%c) ",
 | |
|                 box_id, box->start, box->start + box->len - 1, box->len, box_weight,
 | |
|                 ar, rr, gr, br, "argb"[longest], box->sorted_by == longest ? 'y' : 'n');
 | |
| 
 | |
|         /* sort the range by its longest axis if it's not already sorted */
 | |
|         if (box->sorted_by != longest) {
 | |
|             cmp_func cmpf = cmp_funcs[longest];
 | |
|             AV_QSORT(&s->refs[box->start], box->len, const struct color_ref *, cmpf);
 | |
|             box->sorted_by = longest;
 | |
|         }
 | |
| 
 | |
|         /* locate the median where to split */
 | |
|         median = (box_weight + 1) >> 1;
 | |
|         box_weight = 0;
 | |
|         /* if you have 2 boxes, the maximum is actually #0: you must have at
 | |
|          * least 1 color on each side of the split, hence the -2 */
 | |
|         for (i = box->start; i < box->start + box->len - 2; i++) {
 | |
|             box_weight += s->refs[i]->count;
 | |
|             if (box_weight > median)
 | |
|                 break;
 | |
|         }
 | |
|         ff_dlog(ctx, "split @ i=%-6d with w=%-6"PRIu64" (target=%6"PRIu64")\n", i, box_weight, median);
 | |
|         split_box(s, box, i);
 | |
| 
 | |
|         box_id = get_next_box_id_to_split(s);
 | |
|         box = box_id >= 0 ? &s->boxes[box_id] : NULL;
 | |
|     }
 | |
| 
 | |
|     ratio = set_colorquant_ratio_meta(out, s->nb_boxes, s->nb_refs);
 | |
|     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);
 | |
| 
 | |
|     qsort(s->boxes, s->nb_boxes, sizeof(*s->boxes), cmp_color);
 | |
| 
 | |
|     write_palette(ctx, out);
 | |
| 
 | |
|     return out;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Hashing function for the color.
 | |
|  * It keeps the NBITS least significant bit of each component to make it
 | |
|  * "random" even if the scene doesn't have much different colors.
 | |
|  */
 | |
| static inline unsigned color_hash(uint32_t color, int use_alpha)
 | |
| {
 | |
|     const uint8_t r = color >> 16 & ((1<<NBITS)-1);
 | |
|     const uint8_t g = color >>  8 & ((1<<NBITS)-1);
 | |
|     const uint8_t b = color       & ((1<<NBITS)-1);
 | |
| 
 | |
|     if (use_alpha) {
 | |
|         const uint8_t a = color >> 24 & ((1 << NBITS) - 1);
 | |
|         return a << (NBITS * 3) | r << (NBITS * 2) | g << NBITS | b;
 | |
|     }
 | |
| 
 | |
|     return r << (NBITS * 2) | g << NBITS | b;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Locate the color in the hash table and increment its counter.
 | |
|  */
 | |
| static int color_inc(struct hist_node *hist, uint32_t color, int use_alpha)
 | |
| {
 | |
|     int i;
 | |
|     const unsigned hash = color_hash(color, use_alpha);
 | |
|     struct hist_node *node = &hist[hash];
 | |
|     struct color_ref *e;
 | |
| 
 | |
|     for (i = 0; i < node->nb_entries; i++) {
 | |
|         e = &node->entries[i];
 | |
|         if (e->color == color) {
 | |
|             e->count++;
 | |
|             return 0;
 | |
|         }
 | |
|     }
 | |
| 
 | |
|     e = av_dynarray2_add((void**)&node->entries, &node->nb_entries,
 | |
|                          sizeof(*node->entries), NULL);
 | |
|     if (!e)
 | |
|         return AVERROR(ENOMEM);
 | |
|     e->color = color;
 | |
|     e->count = 1;
 | |
|     return 1;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Update histogram when pixels differ from previous frame.
 | |
|  */
 | |
| static int update_histogram_diff(struct hist_node *hist,
 | |
|                                  const AVFrame *f1, const AVFrame *f2, int use_alpha)
 | |
| {
 | |
|     int x, y, ret, nb_diff_colors = 0;
 | |
| 
 | |
|     for (y = 0; y < f1->height; y++) {
 | |
|         const uint32_t *p = (const uint32_t *)(f1->data[0] + y*f1->linesize[0]);
 | |
|         const uint32_t *q = (const uint32_t *)(f2->data[0] + y*f2->linesize[0]);
 | |
| 
 | |
|         for (x = 0; x < f1->width; x++) {
 | |
|             if (p[x] == q[x])
 | |
|                 continue;
 | |
|             ret = color_inc(hist, p[x], use_alpha);
 | |
|             if (ret < 0)
 | |
|                 return ret;
 | |
|             nb_diff_colors += ret;
 | |
|         }
 | |
|     }
 | |
|     return nb_diff_colors;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Simple histogram of the frame.
 | |
|  */
 | |
| static int update_histogram_frame(struct hist_node *hist, const AVFrame *f, int use_alpha)
 | |
| {
 | |
|     int x, y, ret, nb_diff_colors = 0;
 | |
| 
 | |
|     for (y = 0; y < f->height; y++) {
 | |
|         const uint32_t *p = (const uint32_t *)(f->data[0] + y*f->linesize[0]);
 | |
| 
 | |
|         for (x = 0; x < f->width; x++) {
 | |
|             ret = color_inc(hist, p[x], use_alpha);
 | |
|             if (ret < 0)
 | |
|                 return ret;
 | |
|             nb_diff_colors += ret;
 | |
|         }
 | |
|     }
 | |
|     return nb_diff_colors;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Update the histogram for each passing frame. No frame will be pushed here.
 | |
|  */
 | |
| static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 | |
| {
 | |
|     AVFilterContext *ctx = inlink->dst;
 | |
|     PaletteGenContext *s = ctx->priv;
 | |
|     int ret = s->prev_frame ? update_histogram_diff(s->histogram, s->prev_frame, in, s->use_alpha)
 | |
|                             : update_histogram_frame(s->histogram, in, s->use_alpha);
 | |
| 
 | |
|     if (ret > 0)
 | |
|         s->nb_refs += ret;
 | |
| 
 | |
|     if (s->stats_mode == STATS_MODE_DIFF_FRAMES) {
 | |
|         av_frame_free(&s->prev_frame);
 | |
|         s->prev_frame = in;
 | |
|     } else if (s->stats_mode == STATS_MODE_SINGLE_FRAMES) {
 | |
|         AVFrame *out;
 | |
|         int i;
 | |
| 
 | |
|         out = get_palette_frame(ctx);
 | |
|         out->pts = in->pts;
 | |
|         av_frame_free(&in);
 | |
|         ret = ff_filter_frame(ctx->outputs[0], out);
 | |
|         for (i = 0; i < HIST_SIZE; i++)
 | |
|             av_freep(&s->histogram[i].entries);
 | |
|         av_freep(&s->refs);
 | |
|         s->nb_refs = 0;
 | |
|         s->nb_boxes = 0;
 | |
|         memset(s->boxes, 0, sizeof(s->boxes));
 | |
|         memset(s->histogram, 0, sizeof(s->histogram));
 | |
|     } else {
 | |
|         av_frame_free(&in);
 | |
|     }
 | |
| 
 | |
|     return ret;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Returns only one frame at the end containing the full palette.
 | |
|  */
 | |
| static int request_frame(AVFilterLink *outlink)
 | |
| {
 | |
|     AVFilterContext *ctx = outlink->src;
 | |
|     AVFilterLink *inlink = ctx->inputs[0];
 | |
|     PaletteGenContext *s = ctx->priv;
 | |
|     int r;
 | |
| 
 | |
|     r = ff_request_frame(inlink);
 | |
|     if (r == AVERROR_EOF && !s->palette_pushed && s->nb_refs && s->stats_mode != STATS_MODE_SINGLE_FRAMES) {
 | |
|         r = ff_filter_frame(outlink, get_palette_frame(ctx));
 | |
|         s->palette_pushed = 1;
 | |
|         return r;
 | |
|     }
 | |
|     return r;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * The output is one simple 16x16 squared-pixels palette.
 | |
|  */
 | |
| static int config_output(AVFilterLink *outlink)
 | |
| {
 | |
|     outlink->w = outlink->h = 16;
 | |
|     outlink->sample_aspect_ratio = av_make_q(1, 1);
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| static int init(AVFilterContext *ctx)
 | |
| {
 | |
|     PaletteGenContext* s = ctx->priv;
 | |
| 
 | |
|     if (s->use_alpha && s->reserve_transparent)
 | |
|         s->reserve_transparent = 0;
 | |
| 
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| static av_cold void uninit(AVFilterContext *ctx)
 | |
| {
 | |
|     int i;
 | |
|     PaletteGenContext *s = ctx->priv;
 | |
| 
 | |
|     for (i = 0; i < HIST_SIZE; i++)
 | |
|         av_freep(&s->histogram[i].entries);
 | |
|     av_freep(&s->refs);
 | |
|     av_frame_free(&s->prev_frame);
 | |
| }
 | |
| 
 | |
| static const AVFilterPad palettegen_inputs[] = {
 | |
|     {
 | |
|         .name         = "default",
 | |
|         .type         = AVMEDIA_TYPE_VIDEO,
 | |
|         .filter_frame = filter_frame,
 | |
|     },
 | |
| };
 | |
| 
 | |
| static const AVFilterPad palettegen_outputs[] = {
 | |
|     {
 | |
|         .name          = "default",
 | |
|         .type          = AVMEDIA_TYPE_VIDEO,
 | |
|         .config_props  = config_output,
 | |
|         .request_frame = request_frame,
 | |
|     },
 | |
| };
 | |
| 
 | |
| const AVFilter ff_vf_palettegen = {
 | |
|     .name          = "palettegen",
 | |
|     .description   = NULL_IF_CONFIG_SMALL("Find the optimal palette for a given stream."),
 | |
|     .priv_size     = sizeof(PaletteGenContext),
 | |
|     .init          = init,
 | |
|     .uninit        = uninit,
 | |
|     FILTER_INPUTS(palettegen_inputs),
 | |
|     FILTER_OUTPUTS(palettegen_outputs),
 | |
|     FILTER_QUERY_FUNC(query_formats),
 | |
|     .priv_class    = &palettegen_class,
 | |
| };
 | 
