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avfilter: add paletteuse filter

tags/n2.6
Clément Bœsch 11 years ago
parent
9b964690e3
commit
bab4fcebb1
4 changed files with 989 additions and 0 deletions
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  1. +50
    -0
      doc/filters.texi
  2. +1
    -0
      libavfilter/Makefile
  3. +1
    -0
      libavfilter/allfilters.c
  4. +937
    -0
      libavfilter/vf_paletteuse.c

+ 50
- 0
doc/filters.texi View File

@@ -6909,6 +6909,7 @@ pad="2*iw:2*ih:ow-iw:oh-ih"
@end example
@end itemize

@anchor{palettegen}
@section palettegen

Generate one palette for a whole video stream.
@@ -6954,6 +6955,55 @@ ffmpeg -i input.mkv -vf palettegen palette.png
@end example
@end itemize

@section paletteuse

Use a palette to downsample an input video stream.

The filter takes two inputs: one video stream and a palette. The palette must
be a 256 pixels image.

It accepts the following options:

@table @option
@item dither
Select dithering mode. Available algorithms are:
@table @samp
@item bayer
Ordered 8x8 bayer dithering (deterministic)
@item heckbert
Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
Note: this dithering is sometimes considered "wrong" and is included as a
reference.
@item floyd_steinberg
Floyd and Steingberg dithering (error diffusion)
@item sierra2
Frankie Sierra dithering v2 (error diffusion)
@item sierra2_4a
Frankie Sierra dithering v2 "Lite" (error diffusion)
@end table

Default is @var{sierra2_4a}.

@item bayer_scale
When @var{bayer} dithering is selected, this option defines the scale of the
pattern (how much the crosshatch pattern is visible). A low value means more
visible pattern for less banding, and higher value means less visible pattern
at the cost of more banding.

The option must be an integer value in the range [0,5]. Default is @var{2}.
@end table

@subsection Examples

@itemize
@item
Use a palette (generated for example with @ref{palettegen}) to encode a GIF
using @command{ffmpeg}:
@example
ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
@end example
@end itemize

@section perspective

Correct perspective of video not recorded perpendicular to the screen.


+ 1
- 0
libavfilter/Makefile View File

@@ -161,6 +161,7 @@ OBJS-$(CONFIG_OVERLAY_FILTER) += vf_overlay.o dualinput.o framesy
OBJS-$(CONFIG_OWDENOISE_FILTER) += vf_owdenoise.o
OBJS-$(CONFIG_PAD_FILTER) += vf_pad.o
OBJS-$(CONFIG_PALETTEGEN_FILTER) += vf_palettegen.o
OBJS-$(CONFIG_PALETTEUSE_FILTER) += vf_paletteuse.o dualinput.o framesync.o
OBJS-$(CONFIG_PERMS_FILTER) += f_perms.o
OBJS-$(CONFIG_PERSPECTIVE_FILTER) += vf_perspective.o
OBJS-$(CONFIG_PHASE_FILTER) += vf_phase.o


+ 1
- 0
libavfilter/allfilters.c View File

@@ -176,6 +176,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(OWDENOISE, owdenoise, vf);
REGISTER_FILTER(PAD, pad, vf);
REGISTER_FILTER(PALETTEGEN, palettegen, vf);
REGISTER_FILTER(PALETTEUSE, paletteuse, vf);
REGISTER_FILTER(PERMS, perms, vf);
REGISTER_FILTER(PERSPECTIVE, perspective, vf);
REGISTER_FILTER(PHASE, phase, vf);


+ 937
- 0
libavfilter/vf_paletteuse.c View File

@@ -0,0 +1,937 @@
/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

/**
* @file
* Use a palette to downsample an input video stream.
*/

#include "libavutil/bprint.h"
#include "libavutil/opt.h"
#include "dualinput.h"
#include "avfilter.h"

enum dithering_mode {
DITHERING_NONE,
DITHERING_BAYER,
DITHERING_HECKBERT,
DITHERING_FLOYD_STEINBERG,
DITHERING_SIERRA2,
DITHERING_SIERRA2_4A,
NB_DITHERING
};

enum color_search_method {
COLOR_SEARCH_NNS_ITERATIVE,
COLOR_SEARCH_NNS_RECURSIVE,
COLOR_SEARCH_BRUTEFORCE,
NB_COLOR_SEARCHES
};

struct color_node {
uint8_t val[3];
uint8_t palette_id;
int split;
int left_id, right_id;
};

#define NBITS 4
#define CACHE_SIZE (1<<(3*NBITS))

struct cached_color {
uint32_t color;
uint8_t pal_entry;
};

struct cache_node {
struct cached_color *entries;
int nb_entries;
};

struct PaletteUseContext;

typedef int (*set_frame_func)(struct PaletteUseContext *s, AVFrame *out, AVFrame *in);

typedef struct PaletteUseContext {
const AVClass *class;
FFDualInputContext dinput;
struct cache_node cache[CACHE_SIZE]; /* lookup cache */
struct color_node map[AVPALETTE_COUNT]; /* 3D-Tree (KD-Tree with K=3) for reverse colormap */
uint32_t palette[AVPALETTE_COUNT];
int palette_loaded;
int dither;
set_frame_func set_frame;
int bayer_scale;
int ordered_dither[8*8];

/* debug options */
char *dot_filename;
int color_search_method;
int calc_mean_err;
uint64_t total_mean_err;
int debug_accuracy;
} PaletteUseContext;

#define OFFSET(x) offsetof(PaletteUseContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption paletteuse_options[] = {
{ "dither", "select dithering mode", OFFSET(dither), AV_OPT_TYPE_INT, {.i64=DITHERING_SIERRA2_4A}, 0, NB_DITHERING-1, FLAGS, "dithering_mode" },
{ "bayer", "ordered 8x8 bayer dithering (deterministic)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_BAYER}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "heckbert", "dithering as defined by Paul Heckbert in 1982 (simple error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_HECKBERT}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "floyd_steinberg", "Floyd and Steingberg dithering (error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_FLOYD_STEINBERG}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "sierra2", "Frankie Sierra dithering v2 (error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_SIERRA2}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "sierra2_4a", "Frankie Sierra dithering v2 \"Lite\" (error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_SIERRA2_4A}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "bayer_scale", "set scale for bayer dithering", OFFSET(bayer_scale), AV_OPT_TYPE_INT, {.i64=2}, 0, 5, FLAGS },

/* following are the debug options, not part of the official API */
{ "debug_kdtree", "save Graphviz graph of the kdtree in specified file", OFFSET(dot_filename), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "color_search", "set reverse colormap color search method", OFFSET(color_search_method), AV_OPT_TYPE_INT, {.i64=COLOR_SEARCH_NNS_ITERATIVE}, 0, NB_COLOR_SEARCHES-1, FLAGS, "search" },
{ "nns_iterative", "iterative search", 0, AV_OPT_TYPE_CONST, {.i64=COLOR_SEARCH_NNS_ITERATIVE}, INT_MIN, INT_MAX, FLAGS, "search" },
{ "nns_recursive", "recursive search", 0, AV_OPT_TYPE_CONST, {.i64=COLOR_SEARCH_NNS_RECURSIVE}, INT_MIN, INT_MAX, FLAGS, "search" },
{ "bruteforce", "brute-force into the palette", 0, AV_OPT_TYPE_CONST, {.i64=COLOR_SEARCH_BRUTEFORCE}, INT_MIN, INT_MAX, FLAGS, "search" },
{ "mean_err", "compute and print mean error", OFFSET(calc_mean_err), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
{ "debug_accuracy", "test color search accuracy", OFFSET(debug_accuracy), AV_OPT_TYPE_FLAGS, {.i64=0}, 0, 1, FLAGS },
{ NULL }
};

AVFILTER_DEFINE_CLASS(paletteuse);

static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat in_fmts[] = {AV_PIX_FMT_RGB32, AV_PIX_FMT_NONE};
static const enum AVPixelFormat inpal_fmts[] = {AV_PIX_FMT_RGB32, AV_PIX_FMT_NONE};
static const enum AVPixelFormat out_fmts[] = {AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE};
AVFilterFormats *in = ff_make_format_list(in_fmts);
AVFilterFormats *inpal = ff_make_format_list(inpal_fmts);
AVFilterFormats *out = ff_make_format_list(out_fmts);
if (!in || !inpal || !out)
return AVERROR(ENOMEM);
ff_formats_ref(in, &ctx->inputs[0]->out_formats);
ff_formats_ref(inpal, &ctx->inputs[1]->out_formats);
ff_formats_ref(out, &ctx->outputs[0]->in_formats);
return 0;
}

static av_always_inline int dither_color(uint32_t px, int er, int eg, int eb, int scale, int shift)
{
return av_clip_uint8((px >> 16 & 0xff) + ((er * scale) >> shift)) << 16
| av_clip_uint8((px >> 8 & 0xff) + ((eg * scale) >> shift)) << 8
| av_clip_uint8((px & 0xff) + ((eb * scale) >> shift));
}

static av_always_inline int diff(const uint8_t *c1, const uint8_t *c2)
{
// XXX: try L*a*b with CIE76 (dL*dL + da*da + db*db)
const int dr = c1[0] - c2[0];
const int dg = c1[1] - c2[1];
const int db = c1[2] - c2[2];
return dr*dr + dg*dg + db*db;
}

static av_always_inline uint8_t colormap_nearest_bruteforce(const uint32_t *palette, const uint8_t *rgb)
{
int i, pal_id = -1, min_dist = INT_MAX;

for (i = 0; i < AVPALETTE_COUNT; i++) {
const uint32_t c = palette[i];

if ((c & 0xff000000) == 0xff000000) { // ignore transparent entry
const uint8_t palrgb[] = {
palette[i]>>16 & 0xff,
palette[i]>> 8 & 0xff,
palette[i] & 0xff,
};
const int d = diff(palrgb, rgb);
if (d < min_dist) {
pal_id = i;
min_dist = d;
}
}
}
return pal_id;
}

/* Recursive form, simpler but a bit slower. Kept for reference. */
struct nearest_color {
int node_pos;
int dist_sqd;
};

static void colormap_nearest_node(const struct color_node *map,
const int node_pos,
const uint8_t *target,
struct nearest_color *nearest)
{
const struct color_node *kd = map + node_pos;
const int s = kd->split;
int dx, nearer_kd_id, further_kd_id;
const uint8_t *current = kd->val;
const int current_to_target = diff(target, current);

if (current_to_target < nearest->dist_sqd) {
nearest->node_pos = node_pos;
nearest->dist_sqd = current_to_target;
}

if (kd->left_id != -1 || kd->right_id != -1) {
dx = target[s] - current[s];

if (dx <= 0) nearer_kd_id = kd->left_id, further_kd_id = kd->right_id;
else nearer_kd_id = kd->right_id, further_kd_id = kd->left_id;

if (nearer_kd_id != -1)
colormap_nearest_node(map, nearer_kd_id, target, nearest);

if (further_kd_id != -1 && dx*dx < nearest->dist_sqd)
colormap_nearest_node(map, further_kd_id, target, nearest);
}
}

static av_always_inline uint8_t colormap_nearest_recursive(const struct color_node *node, const uint8_t *rgb)
{
struct nearest_color res = {.dist_sqd = INT_MAX, .node_pos = -1};
colormap_nearest_node(node, 0, rgb, &res);
return node[res.node_pos].palette_id;
}

struct stack_node {
int color_id;
int dx2;
};

static av_always_inline uint8_t colormap_nearest_iterative(const struct color_node *root, const uint8_t *target)
{
int pos = 0, best_node_id = -1, best_dist = INT_MAX, cur_color_id = 0;
struct stack_node nodes[16];
struct stack_node *node = &nodes[0];

for (;;) {

const struct color_node *kd = &root[cur_color_id];
const uint8_t *current = kd->val;
const int current_to_target = diff(target, current);

/* Compare current color node to the target and update our best node if
* it's actually better. */
if (current_to_target < best_dist) {
best_node_id = cur_color_id;
if (!current_to_target)
goto end; // exact match, we can return immediately
best_dist = current_to_target;
}

/* Check if it's not a leaf */
if (kd->left_id != -1 || kd->right_id != -1) {
const int split = kd->split;
const int dx = target[split] - current[split];
int nearer_kd_id, further_kd_id;

/* Define which side is the most interesting. */
if (dx <= 0) nearer_kd_id = kd->left_id, further_kd_id = kd->right_id;
else nearer_kd_id = kd->right_id, further_kd_id = kd->left_id;

if (nearer_kd_id != -1) {
if (further_kd_id != -1) {
/* Here, both paths are defined, so we push a state for
* when we are going back. */
node->color_id = further_kd_id;
node->dx2 = dx*dx;
pos++;
node++;
}
/* We can now update current color with the most probable path
* (no need to create a state since there is nothing to save
* anymore). */
cur_color_id = nearer_kd_id;
continue;
} else if (dx*dx < best_dist) {
/* The nearest path isn't available, so there is only one path
* possible and it's the least probable. We enter it only if the
* distance from the current point to the hyper rectangle is
* less than our best distance. */
cur_color_id = further_kd_id;
continue;
}
}

/* Unstack as much as we can, typically as long as the least probable
* branch aren't actually probable. */
do {
if (--pos < 0)
goto end;
node--;
} while (node->dx2 >= best_dist);

/* We got a node where the least probable branch might actually contain
* a relevant color. */
cur_color_id = node->color_id;
}

end:
return root[best_node_id].palette_id;
}

#define COLORMAP_NEAREST(search, palette, root, target) \
search == COLOR_SEARCH_NNS_ITERATIVE ? colormap_nearest_iterative(root, target) : \
search == COLOR_SEARCH_NNS_RECURSIVE ? colormap_nearest_recursive(root, target) : \
colormap_nearest_bruteforce(palette, target)

/**
* Check if the requested color is in the cache already. If not, find it in the
* color tree and cache it.
* Note: r, g, and b are the component of c but are passed as well to avoid
* recomputing them (they are generally computed by the caller for other uses).
*/
static av_always_inline uint8_t color_get(struct cache_node *cache, uint32_t color,
uint8_t r, uint8_t g, uint8_t b,
const struct color_node *map,
const uint32_t *palette,
const enum color_search_method search_method)
{
int i;
const uint8_t rgb[] = {r, g, b};
const uint8_t rhash = r & ((1<<NBITS)-1);
const uint8_t ghash = g & ((1<<NBITS)-1);
const uint8_t bhash = b & ((1<<NBITS)-1);
const unsigned hash = rhash<<(NBITS*2) | ghash<<NBITS | bhash;
struct cache_node *node = &cache[hash];
struct cached_color *e;

for (i = 0; i < node->nb_entries; i++) {
e = &node->entries[i];
if (e->color == color)
return e->pal_entry;
}

e = av_dynarray2_add((void**)&node->entries, &node->nb_entries,
sizeof(*node->entries), NULL);
if (!e)
return AVERROR(ENOMEM);
e->color = color;
e->pal_entry = COLORMAP_NEAREST(search_method, palette, map, rgb);
return e->pal_entry;
}

static av_always_inline uint8_t get_dst_color_err(struct cache_node *cache,
uint32_t c, const struct color_node *map,
const uint32_t *palette,
int *er, int *eg, int *eb,
const enum color_search_method search_method)
{
const uint8_t r = c >> 16 & 0xff;
const uint8_t g = c >> 8 & 0xff;
const uint8_t b = c & 0xff;
const uint8_t dstx = color_get(cache, c, r, g, b, map, palette, search_method);
const uint32_t dstc = palette[dstx];
*er = r - (dstc >> 16 & 0xff);
*eg = g - (dstc >> 8 & 0xff);
*eb = b - (dstc & 0xff);
return dstx;
}

static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFrame *in,
enum dithering_mode dither,
const enum color_search_method search_method)
{
int x, y;
const struct color_node *map = s->map;
struct cache_node *cache = s->cache;
const uint32_t *palette = s->palette;
uint32_t *src = (uint32_t *)in ->data[0];
uint8_t *dst = out->data[0];
const int src_linesize = in ->linesize[0] >> 2;
const int dst_linesize = out->linesize[0];

for (y = 0; y < in->height; y++) {
for (x = 0; x < in->width; x++) {
int er, eg, eb;

if (dither == DITHERING_BAYER) {
const int d = s->ordered_dither[(y & 7)<<3 | (x & 7)];
const uint8_t r8 = src[x] >> 16 & 0xff;
const uint8_t g8 = src[x] >> 8 & 0xff;
const uint8_t b8 = src[x] & 0xff;
const uint8_t r = av_clip_uint8(r8 + d);
const uint8_t g = av_clip_uint8(g8 + d);
const uint8_t b = av_clip_uint8(b8 + d);
const uint32_t c = r<<16 | g<<8 | b;
const int color = color_get(cache, c, r, g, b, map, palette, search_method);

if (color < 0)
return color;
dst[x] = color;

} else if (dither == DITHERING_HECKBERT) {
const int right = x < in->width - 1, down = y < in->height - 1;
const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);

if (color < 0)
return color;
dst[x] = color;

if (right) src[ x + 1] = dither_color(src[ x + 1], er, eg, eb, 3, 3);
if ( down) src[src_linesize + x ] = dither_color(src[src_linesize + x ], er, eg, eb, 3, 3);
if (right && down) src[src_linesize + x + 1] = dither_color(src[src_linesize + x + 1], er, eg, eb, 2, 3);

} else if (dither == DITHERING_FLOYD_STEINBERG) {
const int right = x < in->width - 1, down = y < in->height - 1, left = x > 0;
const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);

if (color < 0)
return color;
dst[x] = color;

if (right) src[ x + 1] = dither_color(src[ x + 1], er, eg, eb, 7, 4);
if (left && down) src[src_linesize + x - 1] = dither_color(src[src_linesize + x - 1], er, eg, eb, 3, 4);
if ( down) src[src_linesize + x ] = dither_color(src[src_linesize + x ], er, eg, eb, 5, 4);
if (right && down) src[src_linesize + x + 1] = dither_color(src[src_linesize + x + 1], er, eg, eb, 1, 4);

} else if (dither == DITHERING_SIERRA2) {
const int right = x < in->width - 1, down = y < in->height - 1, left = x > 0;
const int right2 = x < in->width - 2, left2 = x > 1;
const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);

if (color < 0)
return color;
dst[x] = color;

if (right) src[ x + 1] = dither_color(src[ x + 1], er, eg, eb, 4, 4);
if (right2) src[ x + 2] = dither_color(src[ x + 2], er, eg, eb, 3, 4);

if (down) {
if (left2) src[ src_linesize + x - 2] = dither_color(src[ src_linesize + x - 2], er, eg, eb, 1, 4);
if (left) src[ src_linesize + x - 1] = dither_color(src[ src_linesize + x - 1], er, eg, eb, 2, 4);
src[ src_linesize + x ] = dither_color(src[ src_linesize + x ], er, eg, eb, 3, 4);
if (right) src[ src_linesize + x + 1] = dither_color(src[ src_linesize + x + 1], er, eg, eb, 2, 4);
if (right2) src[ src_linesize + x + 2] = dither_color(src[ src_linesize + x + 2], er, eg, eb, 1, 4);
}

} else if (dither == DITHERING_SIERRA2_4A) {
const int right = x < in->width - 1, down = y < in->height - 1, left = x > 0;
const int color = get_dst_color_err(cache, src[x], map, palette, &er, &eg, &eb, search_method);

if (color < 0)
return color;
dst[x] = color;

if (right) src[ x + 1] = dither_color(src[ x + 1], er, eg, eb, 2, 2);
if (left && down) src[src_linesize + x - 1] = dither_color(src[src_linesize + x - 1], er, eg, eb, 1, 2);
if ( down) src[src_linesize + x ] = dither_color(src[src_linesize + x ], er, eg, eb, 1, 2);

} else {
const uint8_t r = src[x] >> 16 & 0xff;
const uint8_t g = src[x] >> 8 & 0xff;
const uint8_t b = src[x] & 0xff;
const int color = color_get(cache, src[x] & 0xffffff, r, g, b, map, palette, search_method);

if (color < 0)
return color;
dst[x] = color;
}
}
src += src_linesize;
dst += dst_linesize;
}
return 0;
}

#define INDENT 4
static void disp_node(AVBPrint *buf,
const struct color_node *map,
int parent_id, int node_id,
int depth)
{
const struct color_node *node = &map[node_id];
const uint32_t fontcolor = node->val[0] > 0x50 &&
node->val[1] > 0x50 &&
node->val[2] > 0x50 ? 0 : 0xffffff;
av_bprintf(buf, "%*cnode%d ["
"label=\"%c%02X%c%02X%c%02X%c\" "
"fillcolor=\"#%02x%02x%02x\" "
"fontcolor=\"#%06X\"]\n",
depth*INDENT, ' ', node->palette_id,
"[ "[node->split], node->val[0],
"][ "[node->split], node->val[1],
" ]["[node->split], node->val[2],
" ]"[node->split],
node->val[0], node->val[1], node->val[2],
fontcolor);
if (parent_id != -1)
av_bprintf(buf, "%*cnode%d -> node%d\n", depth*INDENT, ' ',
map[parent_id].palette_id, node->palette_id);
if (node->left_id != -1) disp_node(buf, map, node_id, node->left_id, depth + 1);
if (node->right_id != -1) disp_node(buf, map, node_id, node->right_id, depth + 1);
}

// debug_kdtree=kdtree.dot -> dot -Tpng kdtree.dot > kdtree.png
static int disp_tree(const struct color_node *node, const char *fname)
{
AVBPrint buf;
FILE *f = av_fopen_utf8(fname, "w");

if (!f) {
int ret = AVERROR(errno);
av_log(NULL, AV_LOG_ERROR, "Cannot open file '%s' for writing: %s\n",
fname, av_err2str(ret));
return ret;
}

av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);

av_bprintf(&buf, "digraph {\n");
av_bprintf(&buf, " node [style=filled fontsize=10 shape=box]\n");
disp_node(&buf, node, -1, 0, 0);
av_bprintf(&buf, "}\n");

fwrite(buf.str, 1, buf.len, f);
fclose(f);
av_bprint_finalize(&buf, NULL);
return 0;
}

static int debug_accuracy(const struct color_node *node, const uint32_t *palette,
const enum color_search_method search_method)
{
int r, g, b, ret = 0;

for (r = 0; r < 256; r++) {
for (g = 0; g < 256; g++) {
for (b = 0; b < 256; b++) {
const uint8_t rgb[] = {r, g, b};
const int r1 = COLORMAP_NEAREST(search_method, palette, node, rgb);
const int r2 = colormap_nearest_bruteforce(palette, rgb);
if (r1 != r2) {
const uint32_t c1 = palette[r1];
const uint32_t c2 = palette[r2];
const uint8_t palrgb1[] = { c1>>16 & 0xff, c1>> 8 & 0xff, c1 & 0xff };
const uint8_t palrgb2[] = { c2>>16 & 0xff, c2>> 8 & 0xff, c2 & 0xff };
const int d1 = diff(palrgb1, rgb);
const int d2 = diff(palrgb2, rgb);
if (d1 != d2) {
av_log(NULL, AV_LOG_ERROR,
"/!\\ %02X%02X%02X: %d ! %d (%06X ! %06X) / dist: %d ! %d\n",
r, g, b, r1, r2, c1 & 0xffffff, c2 & 0xffffff, d1, d2);
ret = 1;
}
}
}
}
}
return ret;
}

struct color {
uint32_t value;
uint8_t pal_id;
};

struct color_rect {
uint8_t min[3];
uint8_t max[3];
};

typedef int (*cmp_func)(const void *, const void *);

#define DECLARE_CMP_FUNC(name, pos) \
static int cmp_##name(const void *pa, const void *pb) \
{ \
const struct color *a = pa; \
const struct color *b = pb; \
return (a->value >> (8 * (2 - (pos))) & 0xff) \
- (b->value >> (8 * (2 - (pos))) & 0xff); \
}

DECLARE_CMP_FUNC(r, 0)
DECLARE_CMP_FUNC(g, 1)
DECLARE_CMP_FUNC(b, 2)

static const cmp_func cmp_funcs[] = {cmp_r, cmp_g, cmp_b};

static int get_next_color(const uint8_t *color_used, const uint32_t *palette,
int *component, const struct color_rect *box)
{
int wr, wg, wb;
int i, longest = 0;
unsigned nb_color = 0;
struct color_rect ranges;
struct color tmp_pal[256];

ranges.min[0] = ranges.min[1] = ranges.min[2] = 0xff;
ranges.max[0] = ranges.max[1] = ranges.max[2] = 0x00;

for (i = 0; i < AVPALETTE_COUNT; i++) {
const uint32_t c = palette[i];
const uint8_t r = c >> 16 & 0xff;
const uint8_t g = c >> 8 & 0xff;
const uint8_t b = c & 0xff;

if (color_used[i] ||
r < box->min[0] || g < box->min[1] || b < box->min[2] ||
r > box->max[0] || g > box->max[1] || b > box->max[2])
continue;

if (r < ranges.min[0]) ranges.min[0] = r;
if (g < ranges.min[1]) ranges.min[1] = g;
if (b < ranges.min[2]) ranges.min[2] = b;

if (r > ranges.max[0]) ranges.max[0] = r;
if (g > ranges.max[1]) ranges.max[1] = g;
if (b > ranges.max[2]) ranges.max[2] = b;

tmp_pal[nb_color].value = c;
tmp_pal[nb_color].pal_id = i;

nb_color++;
}

if (!nb_color)
return -1;

/* define longest axis that will be the split component */
wr = ranges.max[0] - ranges.min[0];
wg = ranges.max[1] - ranges.min[1];
wb = ranges.max[2] - ranges.min[2];
if (wr >= wg && wr >= wb) longest = 0;
if (wg >= wr && wg >= wb) longest = 1;
if (wb >= wr && wb >= wg) longest = 2;
*component = longest;

/* sort along this axis to get median */
qsort(tmp_pal, nb_color, sizeof(*tmp_pal), cmp_funcs[longest]);

return tmp_pal[nb_color >> 1].pal_id;
}

static int colormap_insert(struct color_node *map,
uint8_t *color_used,
int *nb_used,
const uint32_t *palette,
const struct color_rect *box)
{
uint32_t c;
int component, cur_id;
int node_left_id = -1, node_right_id = -1;
struct color_node *node;
struct color_rect box1, box2;
const int pal_id = get_next_color(color_used, palette, &component, box);

if (pal_id < 0)
return -1;

/* create new node with that color */
cur_id = (*nb_used)++;
c = palette[pal_id];
node = &map[cur_id];
node->split = component;
node->palette_id = pal_id;
node->val[0] = c>>16 & 0xff;
node->val[1] = c>> 8 & 0xff;
node->val[2] = c & 0xff;

color_used[pal_id] = 1;

/* get the two boxes this node creates */
box1 = box2 = *box;
box1.max[component] = node->val[component];
box2.min[component] = node->val[component] + 1;

node_left_id = colormap_insert(map, color_used, nb_used, palette, &box1);

if (box2.min[component] <= box2.max[component])
node_right_id = colormap_insert(map, color_used, nb_used, palette, &box2);

node->left_id = node_left_id;
node->right_id = node_right_id;

return cur_id;
}

static int cmp_pal_entry(const void *a, const void *b)
{
const int c1 = *(const uint32_t *)a & 0xffffff;
const int c2 = *(const uint32_t *)b & 0xffffff;
return c1 - c2;
}

static void load_colormap(PaletteUseContext *s)
{
int i, nb_used = 0;
uint8_t color_used[AVPALETTE_COUNT] = {0};
uint32_t last_color = 0;
struct color_rect box;

/* disable transparent colors and dups */
qsort(s->palette, AVPALETTE_COUNT, sizeof(*s->palette), cmp_pal_entry);
for (i = 0; i < AVPALETTE_COUNT; i++) {
const uint32_t c = s->palette[i];
if (i != 0 && c == last_color) {
color_used[i] = 1;
continue;
}
last_color = c;
if ((c & 0xff000000) != 0xff000000) {
color_used[i] = 1; // ignore transparent color(s)
continue;
}
}

box.min[0] = box.min[1] = box.min[2] = 0x00;
box.max[0] = box.max[1] = box.max[2] = 0xff;

colormap_insert(s->map, color_used, &nb_used, s->palette, &box);

if (s->dot_filename)
disp_tree(s->map, s->dot_filename);

if (s->debug_accuracy) {
if (!debug_accuracy(s->map, s->palette, s->color_search_method))
av_log(NULL, AV_LOG_INFO, "Accuracy check passed\n");
}
}

static void debug_mean_error(PaletteUseContext *s, const AVFrame *in1,
const AVFrame *in2, int frame_count)
{
int x, y;
const uint32_t *palette = s->palette;
uint32_t *src1 = (uint32_t *)in1->data[0];
uint8_t *src2 = in2->data[0];
const int src1_linesize = in1->linesize[0] >> 2;
const int src2_linesize = in2->linesize[0];
const float div = in1->width * in1->height * 3;
unsigned mean_err = 0;

for (y = 0; y < in1->height; y++) {
for (x = 0; x < in1->width; x++) {
const uint32_t c1 = src1[x];
const uint32_t c2 = palette[src2[x]];
const uint8_t rgb1[] = {c1 >> 16 & 0xff, c1 >> 8 & 0xff, c1 & 0xff};
const uint8_t rgb2[] = {c2 >> 16 & 0xff, c2 >> 8 & 0xff, c2 & 0xff};
mean_err += diff(rgb1, rgb2);
}
src1 += src1_linesize;
src2 += src2_linesize;
}

s->total_mean_err += mean_err;

av_log(NULL, AV_LOG_INFO, "MEP:%.3f TotalMEP:%.3f\n",
mean_err / div, s->total_mean_err / (div * frame_count));
}

static AVFrame *apply_palette(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
PaletteUseContext *s = ctx->priv;
AVFilterLink *outlink = inlink->dst->outputs[0];

AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!out) {
av_frame_free(&in);
return NULL;
}
av_frame_copy_props(out, in);
if (s->set_frame(s, out, in) < 0) {
av_frame_free(&in);
av_frame_free(&out);
return NULL;
}
memcpy(out->data[1], s->palette, AVPALETTE_SIZE);
if (s->calc_mean_err)
debug_mean_error(s, in, out, inlink->frame_count);
av_frame_free(&in);
return out;
}

static int config_output(AVFilterLink *outlink)
{
int ret;
AVFilterContext *ctx = outlink->src;
PaletteUseContext *s = ctx->priv;

outlink->w = ctx->inputs[0]->w;
outlink->h = ctx->inputs[0]->h;

outlink->time_base = ctx->inputs[0]->time_base;
if ((ret = ff_dualinput_init(ctx, &s->dinput)) < 0)
return ret;
return 0;
}

static int config_input_palette(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;

if (inlink->w * inlink->h != AVPALETTE_COUNT) {
av_log(ctx, AV_LOG_ERROR,
"Palette input must contain exactly %d pixels. "
"Specified input has %dx%d=%d pixels\n",
AVPALETTE_COUNT, inlink->w, inlink->h,
inlink->w * inlink->h);
return AVERROR(EINVAL);
}
return 0;
}

static void load_palette(PaletteUseContext *s, const AVFrame *palette_frame)
{
int i, x, y;
const uint32_t *p = (const uint32_t *)palette_frame->data[0];
const int p_linesize = palette_frame->linesize[0] >> 2;

i = 0;
for (y = 0; y < palette_frame->height; y++) {
for (x = 0; x < palette_frame->width; x++)
s->palette[i++] = p[x];
p += p_linesize;
}

load_colormap(s);

s->palette_loaded = 1;
}

static AVFrame *load_apply_palette(AVFilterContext *ctx, AVFrame *main,
const AVFrame *second)
{
AVFilterLink *inlink = ctx->inputs[0];
PaletteUseContext *s = ctx->priv;
if (!s->palette_loaded) {
load_palette(s, second);
}
return apply_palette(inlink, main);
}

static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
PaletteUseContext *s = inlink->dst->priv;
return ff_dualinput_filter_frame(&s->dinput, inlink, in);
}

#define DEFINE_SET_FRAME(color_search, name, value) \
static int set_frame_##name(PaletteUseContext *s, AVFrame *out, AVFrame *in) \
{ \
return set_frame(s, out, in, value, color_search); \
}

#define DEFINE_SET_FRAME_COLOR_SEARCH(color_search, color_search_macro) \
DEFINE_SET_FRAME(color_search_macro, color_search##_##none, DITHERING_NONE) \
DEFINE_SET_FRAME(color_search_macro, color_search##_##bayer, DITHERING_BAYER) \
DEFINE_SET_FRAME(color_search_macro, color_search##_##heckbert, DITHERING_HECKBERT) \
DEFINE_SET_FRAME(color_search_macro, color_search##_##floyd_steinberg, DITHERING_FLOYD_STEINBERG) \
DEFINE_SET_FRAME(color_search_macro, color_search##_##sierra2, DITHERING_SIERRA2) \
DEFINE_SET_FRAME(color_search_macro, color_search##_##sierra2_4a, DITHERING_SIERRA2_4A) \

DEFINE_SET_FRAME_COLOR_SEARCH(nns_iterative, COLOR_SEARCH_NNS_ITERATIVE)
DEFINE_SET_FRAME_COLOR_SEARCH(nns_recursive, COLOR_SEARCH_NNS_RECURSIVE)
DEFINE_SET_FRAME_COLOR_SEARCH(bruteforce, COLOR_SEARCH_BRUTEFORCE)

#define DITHERING_ENTRIES(color_search) { \
set_frame_##color_search##_none, \
set_frame_##color_search##_bayer, \
set_frame_##color_search##_heckbert, \
set_frame_##color_search##_floyd_steinberg, \
set_frame_##color_search##_sierra2, \
set_frame_##color_search##_sierra2_4a, \
}

static const set_frame_func set_frame_lut[NB_COLOR_SEARCHES][NB_DITHERING] = {
DITHERING_ENTRIES(nns_iterative),
DITHERING_ENTRIES(nns_recursive),
DITHERING_ENTRIES(bruteforce),
};

static int dither_value(int p)
{
const int q = p ^ (p >> 3);
return (p & 4) >> 2 | (q & 4) >> 1 \
| (p & 2) << 1 | (q & 2) << 2 \
| (p & 1) << 4 | (q & 1) << 5;
}

static av_cold int init(AVFilterContext *ctx)
{
PaletteUseContext *s = ctx->priv;
s->dinput.repeatlast = 1; // only 1 frame in the palette
s->dinput.process = load_apply_palette;

s->set_frame = set_frame_lut[s->color_search_method][s->dither];

if (s->dither == DITHERING_BAYER) {
int i;
const int delta = 1 << (5 - s->bayer_scale); // to avoid too much luma

for (i = 0; i < FF_ARRAY_ELEMS(s->ordered_dither); i++)
s->ordered_dither[i] = (dither_value(i) >> s->bayer_scale) - delta;
}

return 0;
}

static int request_frame(AVFilterLink *outlink)
{
PaletteUseContext *s = outlink->src->priv;
return ff_dualinput_request_frame(&s->dinput, outlink);
}

static av_cold void uninit(AVFilterContext *ctx)
{
int i;
PaletteUseContext *s = ctx->priv;

ff_dualinput_uninit(&s->dinput);
for (i = 0; i < CACHE_SIZE; i++)
av_freep(&s->cache[i].entries);
}

static const AVFilterPad paletteuse_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.needs_writable = 1, // for error diffusal dithering
},{
.name = "palette",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_input_palette,
.filter_frame = filter_frame,
},
{ NULL }
};

static const AVFilterPad paletteuse_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_output,
.request_frame = request_frame,
},
{ NULL }
};

AVFilter ff_vf_paletteuse = {
.name = "paletteuse",
.description = NULL_IF_CONFIG_SMALL("Use a palette to downsample an input video stream."),
.priv_size = sizeof(PaletteUseContext),
.query_formats = query_formats,
.init = init,
.uninit = uninit,
.inputs = paletteuse_inputs,
.outputs = paletteuse_outputs,
.priv_class = &paletteuse_class,
};

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