[FFmpeg-devel] [PATCH] avfilter: add epx pixel art scaler
Paul B Mahol
onemda at gmail.com
Fri Jan 22 22:20:27 EET 2021
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
doc/filters.texi | 12 ++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_epx.c | 287 +++++++++++++++++++++++++++++++++++++++
4 files changed, 301 insertions(+)
create mode 100644 libavfilter/vf_epx.c
diff --git a/doc/filters.texi b/doc/filters.texi
index d75a1f5a78..7cb0d868d0 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -10940,6 +10940,18 @@ Can be either @var{normal} or @var{diff}. Default is @var{normal}.
between neighbour histogram values.
@end table
+ at section epx
+Apply the EPX magnification filter which is designed for pixel art.
+
+It accepts the following option:
+
+ at table @option
+ at item n
+Set the scaling dimension: @code{2} for @code{2xEPX}, @code{3} for
+ at code{3xEPX}.
+Default is @code{3}.
+ at end table
+
@section eq
Set brightness, contrast, saturation and approximate gamma adjustment.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 44afa79963..fb7bc8f140 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -248,6 +248,7 @@ OBJS-$(CONFIG_DRAWTEXT_FILTER) += vf_drawtext.o
OBJS-$(CONFIG_EDGEDETECT_FILTER) += vf_edgedetect.o
OBJS-$(CONFIG_ELBG_FILTER) += vf_elbg.o
OBJS-$(CONFIG_ENTROPY_FILTER) += vf_entropy.o
+OBJS-$(CONFIG_EPX_FILTER) += vf_epx.o
OBJS-$(CONFIG_EQ_FILTER) += vf_eq.o
OBJS-$(CONFIG_EROSION_FILTER) += vf_neighbor.o
OBJS-$(CONFIG_EROSION_OPENCL_FILTER) += vf_neighbor_opencl.o opencl.o \
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 471844a603..139ba15f7c 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -234,6 +234,7 @@ extern AVFilter ff_vf_drawtext;
extern AVFilter ff_vf_edgedetect;
extern AVFilter ff_vf_elbg;
extern AVFilter ff_vf_entropy;
+extern AVFilter ff_vf_epx;
extern AVFilter ff_vf_eq;
extern AVFilter ff_vf_erosion;
extern AVFilter ff_vf_erosion_opencl;
diff --git a/libavfilter/vf_epx.c b/libavfilter/vf_epx.c
new file mode 100644
index 0000000000..65b8975c23
--- /dev/null
+++ b/libavfilter/vf_epx.c
@@ -0,0 +1,287 @@
+/*
+ * 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
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/avassert.h"
+#include "libavutil/pixdesc.h"
+#include "internal.h"
+
+typedef struct EPXContext {
+ const AVClass *class;
+
+ int n;
+
+ int (*epx_slice)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
+} EPXContext;
+
+typedef struct ThreadData {
+ AVFrame *in, *out;
+} ThreadData;
+
+#define OFFSET(x) offsetof(EPXContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+static const AVOption epx_options[] = {
+ { "n", "set scale factor", OFFSET(n), AV_OPT_TYPE_INT, {.i64 = 3}, 2, 3, .flags = FLAGS },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(epx);
+
+static int epx2_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+ ThreadData *td = arg;
+ const AVFrame *in = td->in;
+ AVFrame *out = td->out;
+ const int slice_start = (in->height * jobnr ) / nb_jobs;
+ const int slice_end = (in->height * (jobnr+1)) / nb_jobs;
+
+ for (int p = 0; p < 1; p++) {
+ const int width = in->width;
+ const int height = in->height;
+ const int src_linesize = in->linesize[p] / 4;
+ const int dst_linesize = out->linesize[p] / 4;
+ const uint32_t *src = (const uint32_t *)in->data[p];
+ uint32_t *dst = (uint32_t *)out->data[p];
+ const uint32_t *src_line[3];
+
+ src_line[0] = src + src_linesize * FFMAX(slice_start - 1, 0);
+ src_line[1] = src + src_linesize * slice_start;
+ src_line[2] = src + src_linesize * FFMIN(slice_start + 1, height-1);
+
+ for (int y = slice_start; y < slice_end; y++) {
+ uint32_t *dst_line[2];
+
+ dst_line[0] = dst + dst_linesize*2*y;
+ dst_line[1] = dst + dst_linesize*(2*y+1);
+
+ for (int x = 0; x < width; x++) {
+ uint32_t E0, E1, E2, E3;
+ uint32_t B, D, E, F, H;
+
+ B = src_line[0][x];
+ D = src_line[1][FFMAX(x-1, 0)];
+ E = src_line[1][x];
+ F = src_line[1][FFMIN(x+1, width - 1)];
+ H = src_line[2][x];
+
+ if (B != H && D != F) {
+ E0 = D == B ? D : E;
+ E1 = B == F ? F : E;
+ E2 = D == H ? D : E;
+ E3 = H == F ? F : E;
+ } else {
+ E0 = E;
+ E1 = E;
+ E2 = E;
+ E3 = E;
+ }
+
+ dst_line[0][x*2] = E0;
+ dst_line[0][x*2+1] = E1;
+ dst_line[1][x*2] = E2;
+ dst_line[1][x*2+1] = E3;
+ }
+
+ src_line[0] = src_line[1];
+ src_line[1] = src_line[2];
+ src_line[2] = src_line[1];
+
+ if (y < height - 1)
+ src_line[2] += src_linesize;
+ }
+ }
+
+ return 0;
+}
+
+static int epx3_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+ ThreadData *td = arg;
+ const AVFrame *in = td->in;
+ AVFrame *out = td->out;
+ const int slice_start = (in->height * jobnr ) / nb_jobs;
+ const int slice_end = (in->height * (jobnr+1)) / nb_jobs;
+
+ for (int p = 0; p < 1; p++) {
+ const int width = in->width;
+ const int height = in->height;
+ const int src_linesize = in->linesize[p] / 4;
+ const int dst_linesize = out->linesize[p] / 4;
+ const uint32_t *src = (const uint32_t *)in->data[p];
+ uint32_t *dst = (uint32_t *)out->data[p];
+ const uint32_t *src_line[3];
+
+ src_line[0] = src + src_linesize * FFMAX(slice_start - 1, 0);
+ src_line[1] = src + src_linesize * slice_start;
+ src_line[2] = src + src_linesize * FFMIN(slice_start + 1, height-1);
+
+ for (int y = slice_start; y < slice_end; y++) {
+ uint32_t *dst_line[3];
+
+ dst_line[0] = dst + dst_linesize*3*y;
+ dst_line[1] = dst + dst_linesize*(3*y+1);
+ dst_line[2] = dst + dst_linesize*(3*y+2);
+
+ for (int x = 0; x < width; x++) {
+ uint32_t E0, E1, E2, E3, E4, E5, E6, E7, E8;
+ uint32_t A, B, C, D, E, F, G, H, I;
+
+ A = src_line[0][FFMAX(x-1, 0)];
+ B = src_line[0][x];
+ C = src_line[0][FFMIN(x+1, width - 1)];
+ D = src_line[1][FFMAX(x-1, 0)];
+ E = src_line[1][x];
+ F = src_line[1][FFMIN(x+1, width - 1)];
+ G = src_line[2][FFMAX(x-1, 0)];
+ H = src_line[2][x];
+ I = src_line[2][FFMIN(x+1, width - 1)];
+
+ if (B != H && D != F) {
+ E0 = D == B ? D : E;
+ E1 = (D == B && E != C) || (B == F && E != A) ? B : E;
+ E2 = B == F ? F : E;
+ E3 = (D == B && E != G) || (D == H && E != A) ? D : E;
+ E4 = E;
+ E5 = (B == F && E != I) || (H == F && E != C) ? F : E;
+ E6 = D == H ? D : E;
+ E7 = (D == H && E != I) || (H == F && E != G) ? H : E;
+ E8 = H == F ? F : E;
+ } else {
+ E0 = E;
+ E1 = E;
+ E2 = E;
+ E3 = E;
+ E4 = E;
+ E5 = E;
+ E6 = E;
+ E7 = E;
+ E8 = E;
+ }
+
+ dst_line[0][x*3] = E0;
+ dst_line[0][x*3+1] = E1;
+ dst_line[0][x*3+2] = E2;
+ dst_line[1][x*3] = E3;
+ dst_line[1][x*3+1] = E4;
+ dst_line[1][x*3+2] = E5;
+ dst_line[2][x*3] = E6;
+ dst_line[2][x*3+1] = E7;
+ dst_line[2][x*3+2] = E8;
+ }
+
+ src_line[0] = src_line[1];
+ src_line[1] = src_line[2];
+ src_line[2] = src_line[1];
+
+ if (y < height - 1)
+ src_line[2] += src_linesize;
+ }
+ }
+
+ return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+ AVFilterContext *ctx = outlink->src;
+ EPXContext *s = ctx->priv;
+ AVFilterLink *inlink = ctx->inputs[0];
+ const AVPixFmtDescriptor *desc;
+
+ desc = av_pix_fmt_desc_get(outlink->format);
+ if (!desc)
+ return AVERROR_BUG;
+
+ outlink->w = inlink->w * s->n;
+ outlink->h = inlink->h * s->n;
+
+ switch (s->n) {
+ case 2:
+ s->epx_slice = epx2_slice;
+ break;
+ case 3:
+ s->epx_slice = epx3_slice;
+ break;
+ }
+
+ return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+ static const enum AVPixelFormat pix_fmts[] = {
+ AV_PIX_FMT_RGBA, AV_PIX_FMT_BGRA, AV_PIX_FMT_ARGB, AV_PIX_FMT_ABGR,
+ AV_PIX_FMT_NONE,
+ };
+
+ AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
+ if (!fmts_list)
+ return AVERROR(ENOMEM);
+ return ff_set_common_formats(ctx, fmts_list);
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+ AVFilterContext *ctx = inlink->dst;
+ AVFilterLink *outlink = ctx->outputs[0];
+ EPXContext *s = ctx->priv;
+ ThreadData td;
+
+ AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+ if (!out) {
+ av_frame_free(&in);
+ return AVERROR(ENOMEM);
+ }
+
+ av_frame_copy_props(out, in);
+
+ td.in = in, td.out = out;
+ ctx->internal->execute(ctx, s->epx_slice, &td, NULL, FFMIN(inlink->h, ff_filter_get_nb_threads(ctx)));
+
+ av_frame_free(&in);
+ return ff_filter_frame(outlink, out);
+}
+
+static const AVFilterPad inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .filter_frame = filter_frame,
+ },
+ { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .config_props = config_output,
+ },
+ { NULL }
+};
+
+AVFilter ff_vf_epx = {
+ .name = "epx",
+ .description = NULL_IF_CONFIG_SMALL("Scale the input using EPX algorithm."),
+ .inputs = inputs,
+ .outputs = outputs,
+ .query_formats = query_formats,
+ .priv_size = sizeof(EPXContext),
+ .priv_class = &epx_class,
+ .flags = AVFILTER_FLAG_SLICE_THREADS,
+};
--
2.17.1
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