[FFmpeg-devel] [PATCH] avfilter: add exposure video filter
Paul B Mahol
onemda at gmail.com
Sun Feb 7 20:51:29 EET 2021
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
doc/filters.texi | 19 +++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_exposure.c | 144 ++++++++++++++++++++++++++++++++++++++
4 files changed, 165 insertions(+)
create mode 100644 libavfilter/vf_exposure.c
diff --git a/doc/filters.texi b/doc/filters.texi
index fd42df579c..d199ed1357 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -11361,6 +11361,25 @@ Six-point interpolation.
@subsection Commands
This filter supports same @ref{commands} as options.
+ at section exposure
+Adjust exposure of the video stream.
+
+The filter accepts the following options:
+
+ at table @option
+ at item exposure
+Set the exposure correction in EV. Allowed range is from -3.0 to 3.0 EV
+Default value is 0 EV.
+
+ at item black
+Set the black level correction. Allowed range is from -1.0 to 1.0.
+Default value is 0.
+ at end table
+
+ at subsection Commands
+
+This filter supports same @ref{commands} as options.
+
@section extractplanes
Extract color channel components from input video stream into
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index d403e2b390..5a611e7a9e 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -259,6 +259,7 @@ OBJS-$(CONFIG_EROSION_FILTER) += vf_neighbor.o
OBJS-$(CONFIG_EROSION_OPENCL_FILTER) += vf_neighbor_opencl.o opencl.o \
opencl/neighbor.o
OBJS-$(CONFIG_ESTDIF_FILTER) += vf_estdif.o
+OBJS-$(CONFIG_EXPOSURE_FILTER) += vf_exposure.o
OBJS-$(CONFIG_EXTRACTPLANES_FILTER) += vf_extractplanes.o
OBJS-$(CONFIG_FADE_FILTER) += vf_fade.o
OBJS-$(CONFIG_FFTDNOIZ_FILTER) += vf_fftdnoiz.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 8ffb2cd82e..31546c268d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -244,6 +244,7 @@ extern AVFilter ff_vf_eq;
extern AVFilter ff_vf_erosion;
extern AVFilter ff_vf_erosion_opencl;
extern AVFilter ff_vf_estdif;
+extern AVFilter ff_vf_exposure;
extern AVFilter ff_vf_extractplanes;
extern AVFilter ff_vf_fade;
extern AVFilter ff_vf_fftdnoiz;
diff --git a/libavfilter/vf_exposure.c b/libavfilter/vf_exposure.c
new file mode 100644
index 0000000000..b7ad075630
--- /dev/null
+++ b/libavfilter/vf_exposure.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2021 Paul B Mahol
+ *
+ * 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 <float.h>
+
+#include "libavutil/opt.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct ExposureContext {
+ const AVClass *class;
+
+ float exposure;
+ float black;
+
+ float scale;
+ int (*do_slice)(AVFilterContext *s, void *arg,
+ int jobnr, int nb_jobs);
+} ExposureContext;
+
+static int exposure_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+ ExposureContext *s = ctx->priv;
+ AVFrame *frame = arg;
+ const int width = frame->width;
+ const int height = frame->height;
+ const int slice_start = (height * jobnr) / nb_jobs;
+ const int slice_end = (height * (jobnr + 1)) / nb_jobs;
+ const float black = s->black;
+ const float scale = s->scale;
+
+ for (int p = 0; p < 3; p++) {
+ const int linesize = frame->linesize[p] / 4;
+ float *ptr = (float *)frame->data[p] + slice_start * linesize;
+ for (int y = slice_start; y < slice_end; y++) {
+ for (int x = 0; x < width; x++)
+ ptr[x] = (ptr[x] - black) * scale;
+
+ ptr += linesize;
+ }
+ }
+
+ return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+ AVFilterContext *ctx = inlink->dst;
+ ExposureContext *s = ctx->priv;
+
+ s->scale = 1.f / (exp2f(-s->exposure) - s->black);
+ ctx->internal->execute(ctx, s->do_slice, frame, NULL,
+ FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));
+
+ return ff_filter_frame(ctx->outputs[0], frame);
+}
+
+static av_cold int query_formats(AVFilterContext *ctx)
+{
+ static const enum AVPixelFormat pixel_fmts[] = {
+ AV_PIX_FMT_GBRPF32, AV_PIX_FMT_GBRAPF32,
+ AV_PIX_FMT_NONE
+ };
+
+ AVFilterFormats *formats = NULL;
+
+ formats = ff_make_format_list(pixel_fmts);
+ if (!formats)
+ return AVERROR(ENOMEM);
+
+ return ff_set_common_formats(ctx, formats);
+}
+
+static av_cold int config_input(AVFilterLink *inlink)
+{
+ AVFilterContext *ctx = inlink->dst;
+ ExposureContext *s = ctx->priv;
+
+ s->do_slice = exposure_slice;
+
+ return 0;
+}
+
+static const AVFilterPad exposure_inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .needs_writable = 1,
+ .filter_frame = filter_frame,
+ .config_props = config_input,
+ },
+ { NULL }
+};
+
+static const AVFilterPad exposure_outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ },
+ { NULL }
+};
+
+#define OFFSET(x) offsetof(ExposureContext, x)
+#define VF AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
+
+static const AVOption exposure_options[] = {
+ { "exposure", "set the exposure correction", OFFSET(exposure), AV_OPT_TYPE_FLOAT, {.dbl=0}, -3, 3, VF },
+ { "black", "set the black level correction", OFFSET(black), AV_OPT_TYPE_FLOAT, {.dbl=0}, -1, 1, VF },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(exposure);
+
+AVFilter ff_vf_exposure = {
+ .name = "exposure",
+ .description = NULL_IF_CONFIG_SMALL("Adjust exposure of the video stream."),
+ .priv_size = sizeof(ExposureContext),
+ .priv_class = &exposure_class,
+ .query_formats = query_formats,
+ .inputs = exposure_inputs,
+ .outputs = exposure_outputs,
+ .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+ .process_command = ff_filter_process_command,
+};
--
2.17.1
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