Atkinson according to
https://bisqwit.iki.fi/jutut/kuvat/ordered_dither/error_diffusion.txt:
* 1 1 / 8
1 1 1
1
---
doc/filters.texi | 2 ++
libavfilter/vf_paletteuse.c | 23 +++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/doc/filters.texi b/doc/filters.texi
index 16a8dde4f3..2672ae6ee7 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -18520,6 +18520,8 @@ 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}.
diff --git a/libavfilter/vf_paletteuse.c b/libavfilter/vf_paletteuse.c
index 3c3b6b3ef8..252ad746f0 100644
--- a/libavfilter/vf_paletteuse.c
+++ b/libavfilter/vf_paletteuse.c
@@ -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)
--
2.39.0
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