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avfilter/paletteuse: add atkinson dithering

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Atkinson according to
https://bisqwit.iki.fi/jutut/kuvat/ordered_dither/error_diffusion.txt:

        *   1   1    / 8
    1   1   1
        1
This commit is contained in:
Clément Bœsch 2022-12-30 11:38:13 +01:00
parent c973e8ae79
commit 68275043a0
2 changed files with 25 additions and 0 deletions
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2
doc/filters.texi
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@ -18528,6 +18528,8 @@ Frankie Sierra dithering v2 "Lite" (error diffusion)
Frankie Sierra dithering v3 (error diffusion)
@item burkes
Burkes dithering (error diffusion)
@item atkinson
Atkinson dithering by Bill Atkinson at Apple Computer (error diffusion)
@end table
Default is @var{sierra2_4a}.

23
libavfilter/vf_paletteuse.c
View File

@ -44,6 +44,7 @@ enum dithering_mode {
DITHERING_SIERRA2_4A,
DITHERING_SIERRA3,
DITHERING_BURKES,
DITHERING_ATKINSON,
NB_DITHERING
};
@ -117,6 +118,7 @@ static const AVOption paletteuse_options[] = {
{ "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" },
{ "sierra3", "Frankie Sierra dithering v3 (error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_SIERRA3}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "burkes", "Burkes dithering (error diffusion)", 0, AV_OPT_TYPE_CONST, {.i64=DITHERING_BURKES}, INT_MIN, INT_MAX, FLAGS, "dithering_mode" },
{ "atkinson", "Atkinson dithering by Bill Atkinson at Apple Computer (error diffusion)",0, AV_OPT_TYPE_CONST, {.i64=DITHERING_ATKINSON}, 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 },
{ "diff_mode", "set frame difference mode", OFFSET(diff_mode), AV_OPT_TYPE_INT, {.i64=DIFF_MODE_NONE}, 0, NB_DIFF_MODE-1, FLAGS, "diff_mode" },
{ "rectangle", "process smallest different rectangle", 0, AV_OPT_TYPE_CONST, {.i64=DIFF_MODE_RECTANGLE}, INT_MIN, INT_MAX, FLAGS, "diff_mode" },
@ -418,6 +420,25 @@ static av_always_inline int set_frame(PaletteUseContext *s, AVFrame *out, AVFram
if (right2) src[src_linesize + x + 2] = dither_color(src[src_linesize + x + 2], er, eg, eb, 2, 5);
}
} else if (dither == DITHERING_ATKINSON) {
const int right = x < w - 1, down = y < h - 1, left = x > x_start;
const int right2 = x < w - 2, down2 = y < h - 2;
const int color = get_dst_color_err(s, src[x], &er, &eg, &eb);
if (color < 0)
return color;
dst[x] = color;
if (right) src[ x + 1] = dither_color(src[ x + 1], er, eg, eb, 1, 3);
if (right2) src[ x + 2] = dither_color(src[ x + 2], er, eg, eb, 1, 3);
if (down) {
if (left) src[src_linesize + x - 1] = dither_color(src[src_linesize + x - 1], er, eg, eb, 1, 3);
if (1) src[src_linesize + x ] = dither_color(src[src_linesize + x ], er, eg, eb, 1, 3);
if (right) src[src_linesize + x + 1] = dither_color(src[src_linesize + x + 1], er, eg, eb, 1, 3);
if (down2) src[src_linesize*2 + x ] = dither_color(src[src_linesize*2 + x ], er, eg, eb, 1, 3);
}
} else {
const int color = color_get(s, src[x]);
@ -894,6 +915,7 @@ DEFINE_SET_FRAME(sierra2, DITHERING_SIERRA2)
DEFINE_SET_FRAME(sierra2_4a, DITHERING_SIERRA2_4A)
DEFINE_SET_FRAME(sierra3, DITHERING_SIERRA3)
DEFINE_SET_FRAME(burkes, DITHERING_BURKES)
DEFINE_SET_FRAME(atkinson, DITHERING_ATKINSON)
static const set_frame_func set_frame_lut[NB_DITHERING] = {
set_frame_none,
@ -904,6 +926,7 @@ static const set_frame_func set_frame_lut[NB_DITHERING] = {
set_frame_sierra2_4a,
set_frame_sierra3,
set_frame_burkes,
set_frame_atkinson,
};
static int dither_value(int p)